Final 'FileBrowser First Stage' merge.

It basically rewrites most of filelist.c, with some more limited changes in other areas of filebrowser.

From user perspective, it:
* Removes some info in 'long' drawing mode (owner, permissions) - OS-specific data that do not really matter in Blender!
* Makes short/long display 'fixed' size (among four choices, like thumbnails mode).
* Allows to list several layers of dirtree at once, in a flat way (inside .blend files and/or real directories).
* Consequently, adds datablocks types filtering.
* Uses way less RAM when listing big directories, especially in thumbnail mode (we are talking of several hundred of MiB spared).
* Generates thumbnails way faster.

From code perspective, it:
* Is ready for asset engine needs (on data structure level in filebrowser's listing).
* Simplifies and makes 'generic' file listing much lighter.
* Separates file listing in three different aspects:
** 'generic' filelisting (in BLI), which becomes a shallow wrapper around stat struct.
** 'filebrowser drawing' filelisting, which only contains current visible subset of the whole list (sliding window), with extra drawing data (strings for size, date/time, preview, etc.).
** 'asset-ready' filelisting, which is used for operations common to 'basic' filehandling and future asset-related one.
* Uses uuid's to handle file selection/state in the browser, instead of using flags in filelisting items.
* Uses much lighter BLI_task handling for previews, instead of heavy 'job' system (using the new 'notifier' timer to handle UI refresh, in similar way to jobs).
* Moves .blend datablocks preview handling to IMB_thumbnail (necessary to avoid storing all datablock previews at once, and gives better consistency and performances too).

Revision: https://developer.blender.org/D1316

Thanks to Campbell & Sergey for the reviews. :)

21 files changed, 2743 insertions, 1067 deletions

diff --git a/release/scripts/startup/bl_ui/space_filebrowser.py b/release/scripts/startup/bl_ui/space_filebrowser.py
index 0d900a41f25..0b9c8474dd9 100644
--- a/release/scripts/startup/bl_ui/space_filebrowser.py
+++ b/release/scripts/startup/bl_ui/space_filebrowser.py
@@ -40,22 +40,23 @@ class FILEBROWSER_HT_header(Header):
         row.operator("file.parent", text="", icon='FILE_PARENT')
         row.operator("file.refresh", text="", icon='FILE_REFRESH')
 
-        row = layout.row()
-        row.separator()
-
-        row = layout.row(align=True)
+        layout.separator()
         layout.operator_context = 'EXEC_DEFAULT'
-        row.operator("file.directory_new", icon='NEWFOLDER')
+        layout.operator("file.directory_new", icon='NEWFOLDER', text="")
+        layout.separator()
 
         layout.operator_context = 'INVOKE_DEFAULT'
         params = st.params
 
         # can be None when save/reload with a file selector open
         if params:
+            is_lib_browser = params.use_library_browsing
+
+            layout.prop(params, "recursion_level", text="")
+
             layout.prop(params, "display_type", expand=True, text="")
 
-            if params.display_type == 'FILE_IMGDISPLAY':
-                layout.prop(params, "thumbnail_size", text="")
+            layout.prop(params, "thumbnail_size", text="")
 
             layout.prop(params, "sort_method", expand=True, text="")
 
@@ -81,9 +82,17 @@ class FILEBROWSER_HT_header(Header):
                 row.prop(params, "use_filter_sound", text="")
                 row.prop(params, "use_filter_text", text="")
 
+            if is_lib_browser:
+                row.prop(params, "use_filter_blendid", text="")
+                if params.use_filter_blendid:
+                    row.separator()
+                    row.prop(params, "filter_id_category", text="")
+
             row.separator()
             row.prop(params, "filter_search", text="", icon='VIEWZOOM')
 
+        layout.template_running_jobs()
+
 
 class FILEBROWSER_UL_dir(bpy.types.UIList):
     def draw_item(self, context, layout, data, item, icon, active_data, active_propname, index):
@@ -214,5 +223,24 @@ class FILEBROWSER_PT_recent_folders(Panel):
             col.operator("file.reset_recent", icon='X', text="")
 
 
+class FILEBROWSER_PT_advanced_filter(Panel):
+    bl_space_type = 'FILE_BROWSER'
+    bl_region_type = 'TOOLS'
+    bl_category = "Filter"
+    bl_label = "Advanced Filter"
+
+    def draw(self, context):
+        layout = self.layout
+        space = context.space_data
+        params = space.params
+
+        if params and params.use_library_browsing:
+            layout.prop(params, "use_filter_blendid")
+            if params.use_filter_blendid:
+                layout.separator()
+                col = layout.column()
+                col.prop(params, "filter_id")
+
+
 if __name__ == "__main__":  # only for live edit.
     bpy.utils.register_module(__name__)
diff --git a/source/blender/blenlib/BLI_fileops.h b/source/blender/blenlib/BLI_fileops.h
index 93842731ab7..ba59c412c3a 100644
--- a/source/blender/blenlib/BLI_fileops.h
+++ b/source/blender/blenlib/BLI_fileops.h
@@ -91,11 +91,19 @@ char  *BLI_current_working_dir(char *dir, const size_t maxlen) ATTR_NONNULL();
 
 /* Filelist */
 
-unsigned int BLI_filelist_dir_contents(const char *dir, struct direntry **filelist);
+unsigned int BLI_filelist_dir_contents(const char *dir, struct direntry **r_filelist);
+void BLI_filelist_entry_duplicate(struct direntry *dst, const struct direntry *src);
 void BLI_filelist_duplicate(
-        struct direntry **dest_filelist, struct direntry *src_filelist, unsigned int nrentries,
-        void *(*dup_poin)(void *));
-void BLI_filelist_free(struct direntry *filelist, unsigned int nrentries, void (*free_poin)(void *));
+        struct direntry **dest_filelist, struct direntry * const src_filelist, const unsigned int nrentries);
+void BLI_filelist_entry_free(struct direntry *entry);
+void BLI_filelist_free(struct direntry *filelist, const unsigned int nrentries);
+
+void BLI_filelist_entry_size_to_string(const struct stat *st, const uint64_t sz, const bool compact, char r_size[]);
+void BLI_filelist_entry_mode_to_string(
+        const struct stat *st, const bool compact, char r_mode1[], char r_mode2[], char r_mode3[]);
+void BLI_filelist_entry_owner_to_string(const struct stat *st, const bool compact, char r_owner[]);
+void BLI_filelist_entry_datetime_to_string(
+        const struct stat *st, const int64_t ts, const bool compact, char r_time[], char r_date[]);
 
 /* Files */
 
diff --git a/source/blender/blenlib/BLI_fileops_types.h b/source/blender/blenlib/BLI_fileops_types.h
index 5a1126b05d2..0cf8c8ddb4a 100644
--- a/source/blender/blenlib/BLI_fileops_types.h
+++ b/source/blender/blenlib/BLI_fileops_types.h
@@ -39,7 +39,11 @@
 typedef unsigned int mode_t;
 #endif
 
-struct ImBuf;
+#define FILELIST_DIRENTRY_SIZE_LEN  16
+#define FILELIST_DIRENTRY_MODE_LEN  4
+#define FILELIST_DIRENTRY_OWNER_LEN 16
+#define FILELIST_DIRENTRY_TIME_LEN  8
+#define FILELIST_DIRENTRY_DATE_LEN  16
 
 struct direntry {
 	mode_t  type;
@@ -56,19 +60,6 @@ struct direntry {
 #else
 	struct stat s;
 #endif
-	unsigned int flags;
-	char    size[16];
-	char    mode1[4];
-	char    mode2[4];
-	char    mode3[4];
-	char    owner[16];
-	char    time[8];
-	char    date[16];
-	char    extra[16];
-	void   *poin;
-	int     nr;
-	struct ImBuf *image;
-	unsigned int selflag; /* selection flag */
 };
 
 struct dirlink {
diff --git a/source/blender/blenlib/intern/BLI_filelist.c b/source/blender/blenlib/intern/BLI_filelist.c
index 38a6781c159..62690ff4f3c 100644
--- a/source/blender/blenlib/intern/BLI_filelist.c
+++ b/source/blender/blenlib/intern/BLI_filelist.c
@@ -182,7 +182,6 @@ static void bli_builddir(struct BuildDirCtx *dir_ctx, const char *dirname)
 						/* Hack around for UNC paths on windows - does not support stat on '\\SERVER\foo\..', sigh... */
 						file->type |= S_IFDIR;
 					}
-					file->flags = 0;
 					dir_ctx->nrfiles++;
 					file++;
 					dlink = dlink->next;
@@ -210,130 +209,160 @@ static void bli_builddir(struct BuildDirCtx *dir_ctx, const char *dirname)
 }
 
 /**
- * Fills in the "mode[123]", "size" and "string" fields in the elements of the files
- * array with descriptive details about each item. "string" will have a format similar to "ls -l".
+ * Scans the contents of the directory named *dirname, and allocates and fills in an
+ * array of entries describing them in *filelist.
+ *
+ * \return The length of filelist array.
  */
-static void bli_adddirstrings(struct BuildDirCtx *dir_ctx)
+unsigned int BLI_filelist_dir_contents(const char *dirname,  struct direntry **r_filelist)
 {
-	const char *types[8] = {"---", "--x", "-w-", "-wx", "r--", "r-x", "rw-", "rwx"};
-	/* symbolic display, indexed by mode field value */
-	int num;
-	double size;
-	struct direntry *file;
-	struct tm *tm;
-	time_t zero = 0;
-
-#ifndef WIN32
-	int mode;
-#endif
-
-	for (num = 0, file = dir_ctx->files; num < dir_ctx->nrfiles; num++, file++) {
+	struct BuildDirCtx dir_ctx;
 
-		/* Mode */
-#ifdef WIN32
-		BLI_strncpy(file->mode1, types[0], sizeof(file->mode1));
-		BLI_strncpy(file->mode2, types[0], sizeof(file->mode2));
-		BLI_strncpy(file->mode3, types[0], sizeof(file->mode3));
-#else
-		mode = file->s.st_mode;
+	dir_ctx.nrfiles = 0;
+	dir_ctx.files = NULL;
 
-		BLI_strncpy(file->mode1, types[(mode & 0700) >> 6], sizeof(file->mode1));
-		BLI_strncpy(file->mode2, types[(mode & 0070) >> 3], sizeof(file->mode2));
-		BLI_strncpy(file->mode3, types[(mode & 0007)],      sizeof(file->mode3));
+	bli_builddir(&dir_ctx, dirname);
 
-		if (((mode & S_ISGID) == S_ISGID) && (file->mode2[2] == '-')) file->mode2[2] = 'l';
+	if (dir_ctx.files) {
+		*r_filelist = dir_ctx.files;
+	}
+	else {
+		// keep blender happy. Blender stores this in a variable
+		// where 0 has special meaning.....
+		*r_filelist = MEM_mallocN(sizeof(**r_filelist), __func__);
+	}
 
-		if (mode & (S_ISUID | S_ISGID)) {
-			if (file->mode1[2] == 'x') file->mode1[2] = 's';
-			else file->mode1[2] = 'S';
+	return dir_ctx.nrfiles;
+}
 
-			if (file->mode2[2] == 'x') file->mode2[2] = 's';
-		}
+/**
+ * Convert given entry's size into human-readable strings.
+ *
+ */
+void BLI_filelist_entry_size_to_string(
+        const struct stat *st, const uint64_t sz, const bool compact, char r_size[FILELIST_DIRENTRY_SIZE_LEN])
+{
+	double size;
+	const char *fmt;
+	const char *units[] = {"KiB", "MiB", "GiB", "TiB", NULL};
+	const char *units_compact[] = {"K", "M", "G", "T", NULL};
+	const char *unit = "B";
+
+	/*
+	 * Seems st_size is signed 32-bit value in *nix and Windows.  This
+	 * will buy us some time until files get bigger than 4GB or until
+	 * everyone starts using __USE_FILE_OFFSET64 or equivalent.
+	 */
+	size = (double)(st ? st->st_size : sz);
+
+	if (size > 1024.0) {
+		const char **u;
+		for (u = compact ? units_compact : units, size /= 1024.0; size > 1024.0 && *(u + 1); u++, size /= 1024.0);
+		fmt =  size > 100.0 ? "%.0f %s" : (size > 10.0 ? "%.1f %s" : "%.2f %s");
+		unit = *u;
+	}
+	else {
+		fmt = "%.0f %s";
+	}
 
-		if (mode & S_ISVTX) {
-			if (file->mode3[2] == 'x') file->mode3[2] = 't';
-			else file->mode3[2] = 'T';
-		}
-#endif
+	BLI_snprintf(r_size, sizeof(*r_size) * FILELIST_DIRENTRY_SIZE_LEN, fmt, size, unit);
+}
 
+/**
+ * Convert given entry's modes into human-readable strings.
+ *
+ */
+void BLI_filelist_entry_mode_to_string(
+        const struct stat *st, const bool UNUSED(compact), char r_mode1[FILELIST_DIRENTRY_MODE_LEN],
+        char r_mode2[FILELIST_DIRENTRY_MODE_LEN], char r_mode3[FILELIST_DIRENTRY_MODE_LEN])
+{
+	const char *types[8] = {"---", "--x", "-w-", "-wx", "r--", "r-x", "rw-", "rwx"};
 
-		/* User */
 #ifdef WIN32
-		strcpy(file->owner, "user");
+	BLI_strncpy(r_mode1, types[0], sizeof(*r_mode1) * FILELIST_DIRENTRY_MODE_LEN);
+	BLI_strncpy(r_mode2, types[0], sizeof(*r_mode2) * FILELIST_DIRENTRY_MODE_LEN);
+	BLI_strncpy(r_mode3, types[0], sizeof(*r_mode3) * FILELIST_DIRENTRY_MODE_LEN);
 #else
-		{
-			struct passwd *pwuser;
-			pwuser = getpwuid(file->s.st_uid);
-			if (pwuser) {
-				BLI_strncpy(file->owner, pwuser->pw_name, sizeof(file->owner));
-			}
-			else {
-				BLI_snprintf(file->owner, sizeof(file->owner), "%u", file->s.st_uid);
-			}
-		}
-#endif
+	const int mode = st->st_mode;
 
+	BLI_strncpy(r_mode1, types[(mode & 0700) >> 6], sizeof(*r_mode1) * FILELIST_DIRENTRY_MODE_LEN);
+	BLI_strncpy(r_mode2, types[(mode & 0070) >> 3], sizeof(*r_mode2) * FILELIST_DIRENTRY_MODE_LEN);
+	BLI_strncpy(r_mode3, types[(mode & 0007)],      sizeof(*r_mode3) * FILELIST_DIRENTRY_MODE_LEN);
 
-		/* Time */
-		tm = localtime(&file->s.st_mtime);
-		// prevent impossible dates in windows
-		if (tm == NULL) tm = localtime(&zero);
-		strftime(file->time, sizeof(file->time), "%H:%M", tm);
-		strftime(file->date, sizeof(file->date), "%d-%b-%y", tm);
+	if (((mode & S_ISGID) == S_ISGID) && (r_mode2[2] == '-')) r_mode2[2] = 'l';
 
+	if (mode & (S_ISUID | S_ISGID)) {
+		if (r_mode1[2] == 'x') r_mode1[2] = 's';
+		else r_mode1[2] = 'S';
 
-		/* Size */
-		/*
-		 * Seems st_size is signed 32-bit value in *nix and Windows.  This
-		 * will buy us some time until files get bigger than 4GB or until
-		 * everyone starts using __USE_FILE_OFFSET64 or equivalent.
-		 */
-		size = (double)file->s.st_size;
+		if (r_mode2[2] == 'x') r_mode2[2] = 's';
+	}
 
-		if (size > 1024.0 * 1024.0 * 1024.0 * 1024.0) {
-			BLI_snprintf(file->size, sizeof(file->size), "%.1f TiB", size / (1024.0 * 1024.0 * 1024.0 * 1024.0));
-		}
-		else if (size > 1024.0 * 1024.0 * 1024.0) {
-			BLI_snprintf(file->size, sizeof(file->size), "%.1f GiB", size / (1024.0 * 1024.0 * 1024.0));
-		}
-		else if (size > 1024.0 * 1024.0) {
-			BLI_snprintf(file->size, sizeof(file->size), "%.1f MiB", size / (1024.0 * 1024.0));
-		}
-		else if (size > 1024.0) {
-			BLI_snprintf(file->size, sizeof(file->size), "%.1f KiB", size / 1024.0);
-		}
-		else {
-			BLI_snprintf(file->size, sizeof(file->size), "%d B", (int)size);
-		}
+	if (mode & S_ISVTX) {
+		if (r_mode3[2] == 'x') r_mode3[2] = 't';
+		else r_mode3[2] = 'T';
 	}
+#endif
 }
 
 /**
- * Scans the contents of the directory named *dirname, and allocates and fills in an
- * array of entries describing them in *filelist.
+ * Convert given entry's owner into human-readable strings.
  *
- * \return The length of filelist array.
  */
-unsigned int BLI_filelist_dir_contents(const char *dirname,  struct direntry **filelist)
+void BLI_filelist_entry_owner_to_string(
+        const struct stat *st, const bool UNUSED(compact), char r_owner[FILELIST_DIRENTRY_OWNER_LEN])
 {
-	struct BuildDirCtx dir_ctx;
+#ifdef WIN32
+	strcpy(r_owner, "unknown");
+#else
+	struct passwd *pwuser = getpwuid(st->st_uid);
 
-	dir_ctx.nrfiles = 0;
-	dir_ctx.files = NULL;
+	if (pwuser) {
+		BLI_strncpy(r_owner, pwuser->pw_name, sizeof(*r_owner) * FILELIST_DIRENTRY_OWNER_LEN);
+	}
+	else {
+		BLI_snprintf(r_owner, sizeof(*r_owner) * FILELIST_DIRENTRY_OWNER_LEN, "%u", st->st_uid);
+	}
+#endif
+}
 
-	bli_builddir(&dir_ctx, dirname);
-	bli_adddirstrings(&dir_ctx);
+/**
+ * Convert given entry's time into human-readable strings.
+ */
+void BLI_filelist_entry_datetime_to_string(
+        const struct stat *st, const int64_t ts, const bool compact,
+        char r_time[FILELIST_DIRENTRY_TIME_LEN], char r_date[FILELIST_DIRENTRY_DATE_LEN])
+{
+	const struct tm *tm = localtime(st ? &st->st_mtime : &ts);
+	const time_t zero = 0;
 
-	if (dir_ctx.files) {
-		*filelist = dir_ctx.files;
+	/* Prevent impossible dates in windows. */
+	if (tm == NULL) {
+		tm = localtime(&zero);
 	}
-	else {
-		// keep blender happy. Blender stores this in a variable
-		// where 0 has special meaning.....
-		*filelist = MEM_mallocN(sizeof(**filelist), __func__);
+
+	if (r_time) {
+		strftime(r_time, sizeof(*r_time) * FILELIST_DIRENTRY_TIME_LEN, "%H:%M", tm);
+	}
+	if (r_date) {
+		strftime(r_date, sizeof(*r_date) * FILELIST_DIRENTRY_DATE_LEN, compact ? "%d/%m/%y" : "%d-%b-%y", tm);
 	}
+}
 
-	return dir_ctx.nrfiles;
+/**
+ * Deep-duplicate of a single direntry.
+ *
+ * \param dup_poin If given, called for each non-NULL direntry->poin. Otherwise, pointer is always simply copied over.
+ */
+void BLI_filelist_entry_duplicate(struct direntry *dst, const struct direntry *src)
+{
+	*dst = *src;
+	if (dst->relname) {
+		dst->relname = MEM_dupallocN(src->relname);
+	}
+	if (dst->path) {
+		dst->path = MEM_dupallocN(src->path);
+	}
 }
 
 /**
@@ -342,48 +371,39 @@ unsigned int BLI_filelist_dir_contents(const char *dirname,  struct direntry **f
  * \param dup_poin If given, called for each non-NULL direntry->poin. Otherwise, pointer is always simply copied over.
  */
 void BLI_filelist_duplicate(
-        struct direntry **dest_filelist, struct direntry *src_filelist, unsigned int nrentries,
-        void *(*dup_poin)(void *))
+        struct direntry **dest_filelist, struct direntry * const src_filelist, const unsigned int nrentries)
 {
 	unsigned int i;
 
 	*dest_filelist = MEM_mallocN(sizeof(**dest_filelist) * (size_t)(nrentries), __func__);
 	for (i = 0; i < nrentries; ++i) {
 		struct direntry * const src = &src_filelist[i];
-		struct direntry *dest = &(*dest_filelist)[i];
-		*dest = *src;
-		if (dest->image) {
-			dest->image = IMB_dupImBuf(src->image);
-		}
-		if (dest->relname) {
-			dest->relname = MEM_dupallocN(src->relname);
-		}
-		if (dest->path) {
-			dest->path = MEM_dupallocN(src->path);
-		}
-		if (dest->poin && dup_poin) {
-			dest->poin = dup_poin(src->poin);
-		}
+		struct direntry *dst = &(*dest_filelist)[i];
+		BLI_filelist_entry_duplicate(dst, src);
+	}
+}
+
+/**
+ * frees storage for a single direntry, not the direntry itself.
+ */
+void BLI_filelist_entry_free(struct direntry *entry)
+{
+	if (entry->relname) {
+		MEM_freeN((void *)entry->relname);
+	}
+	if (entry->path) {
+		MEM_freeN((void *)entry->path);
 	}
 }
 
 /**
  * frees storage for an array of direntries, including the array itself.
  */
-void BLI_filelist_free(struct direntry *filelist, unsigned int nrentries, void (*free_poin)(void *))
+void BLI_filelist_free(struct direntry *filelist, const unsigned int nrentries)
 {
 	unsigned int i;
 	for (i = 0; i < nrentries; ++i) {
-		struct direntry *entry = filelist + i;
-		if (entry->image) {
-			IMB_freeImBuf(entry->image);
-		}
-		if (entry->relname)
-			MEM_freeN((void *)entry->relname);
-		if (entry->path)
-			MEM_freeN((void *)entry->path);
-		if (entry->poin && free_poin)
-			free_poin(entry->poin);
+		BLI_filelist_entry_free(&filelist[i]);
 	}
 
 	if (filelist != NULL) {
diff --git a/source/blender/editors/include/ED_fileselect.h b/source/blender/editors/include/ED_fileselect.h
index b81ea55cca8..186a2a26825 100644
--- a/source/blender/editors/include/ED_fileselect.h
+++ b/source/blender/editors/include/ED_fileselect.h
@@ -33,6 +33,7 @@
 
 struct ARegion;
 struct FileSelectParams;
+struct ScrArea;
 struct SpaceFile;
 struct bContext;
 struct wmWindowManager;
@@ -40,17 +41,13 @@ struct wmWindowManager;
 #define FILE_LAYOUT_HOR 1
 #define FILE_LAYOUT_VER 2
 
-#define MAX_FILE_COLUMN 8
+#define MAX_FILE_COLUMN 4
 
 typedef enum FileListColumns {
 	COLUMN_NAME = 0,
 	COLUMN_DATE,
 	COLUMN_TIME,
 	COLUMN_SIZE,
-	COLUMN_MODE1,
-	COLUMN_MODE2,
-	COLUMN_MODE3,
-	COLUMN_OWNER
 } FileListColumns;
 
 typedef struct FileLayout {
@@ -71,6 +68,9 @@ typedef struct FileLayout {
 	int dirty;
 	int textheight;
 	float column_widths[MAX_FILE_COLUMN];
+
+	/* When we change display size, we may have to update static strings like size of files... */
+	short curr_size;
 } FileLayout;
 
 typedef struct FileSelection {
@@ -100,9 +100,9 @@ void ED_fileselect_layout_tilepos(FileLayout *layout, int tile, int *x, int *y);
 
 void ED_operatormacros_file(void);
 
-void ED_fileselect_clear(struct wmWindowManager *wm, struct SpaceFile *sfile);
+void ED_fileselect_clear(struct wmWindowManager *wm, struct ScrArea *sa, struct SpaceFile *sfile);
 
-void ED_fileselect_exit(struct wmWindowManager *wm, struct SpaceFile *sfile);
+void ED_fileselect_exit(struct wmWindowManager *wm, struct ScrArea *sa, struct SpaceFile *sfile);
 
 int ED_file_extension_icon(const char *relname);
 
diff --git a/source/blender/editors/interface/interface_icons.c b/source/blender/editors/interface/interface_icons.c
index 95139c5656e..5ef3b69c851 100644
--- a/source/blender/editors/interface/interface_icons.c
+++ b/source/blender/editors/interface/interface_icons.c
@@ -757,7 +757,7 @@ static void init_iconfile_list(struct ListBase *list)
 		}
 	}
 
-	BLI_filelist_free(dir, totfile, NULL);
+	BLI_filelist_free(dir, totfile);
 	dir = NULL;
 }
 
diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index 6b2f12eef45..44e130ed896 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -3343,7 +3343,8 @@ void uiTemplateOperatorSearch(uiLayout *layout)
 #define B_STOPCOMPO     4
 #define B_STOPSEQ       5
 #define B_STOPCLIP      6
-#define B_STOPOTHER     7
+#define B_STOPFILE      7
+#define B_STOPOTHER     8
 
 static void do_running_jobs(bContext *C, void *UNUSED(arg), int event)
 {
@@ -3366,6 +3367,9 @@ static void do_running_jobs(bContext *C, void *UNUSED(arg), int event)
 		case B_STOPCLIP:
 			WM_jobs_stop(CTX_wm_manager(C), CTX_wm_area(C), NULL);
 			break;
+		case B_STOPFILE:
+			WM_jobs_stop(CTX_wm_manager(C), CTX_wm_area(C), NULL);
+			break;
 		case B_STOPOTHER:
 			G.is_break = true;
 			break;
@@ -3396,6 +3400,12 @@ void uiTemplateRunningJobs(uiLayout *layout, bContext *C)
 			owner = sa;
 		handle_event = B_STOPCLIP;
 	}
+	else if (sa->spacetype == SPACE_FILE) {
+		if (WM_jobs_test(wm, sa, WM_JOB_TYPE_FILESEL_READDIR)) {
+			owner = sa;
+		}
+		handle_event = B_STOPFILE;
+	}
 	else {
 		Scene *scene;
 		/* another scene can be rendering too, for example via compositor */
diff --git a/source/blender/editors/space_file/CMakeLists.txt b/source/blender/editors/space_file/CMakeLists.txt
index 185ba24eac7..fd701a8be4c 100644
--- a/source/blender/editors/space_file/CMakeLists.txt
+++ b/source/blender/editors/space_file/CMakeLists.txt
@@ -31,6 +31,7 @@ set(INC
 	../../makesrna
 	../../render/extern/include
 	../../windowmanager
+	../../../../intern/atomic
 	../../../../intern/guardedalloc
 	../../../../intern/glew-mx
 )
diff --git a/source/blender/editors/space_file/SConscript b/source/blender/editors/space_file/SConscript
index 6cb7c5a69d4..a66a14a32de 100644
--- a/source/blender/editors/space_file/SConscript
+++ b/source/blender/editors/space_file/SConscript
@@ -29,6 +29,7 @@ Import ('env')
 
 sources = env.Glob('*.c')
 incs = [
+    '#/intern/atomic',
     '#/intern/guardedalloc',
     env['BF_GLEW_INC'],
     '#/intern/glew-mx',
diff --git a/source/blender/editors/space_file/file_draw.c b/source/blender/editors/space_file/file_draw.c
index 9922290bf6f..c809b79bd61 100644
--- a/source/blender/editors/space_file/file_draw.c
+++ b/source/blender/editors/space_file/file_draw.c
@@ -35,6 +35,7 @@
 #include "BLI_blenlib.h"
 #include "BLI_utildefines.h"
 #include "BLI_fileops_types.h"
+#include "BLI_math.h"
 
 #ifdef WIN32
 #  include "BLI_winstuff.h"
@@ -47,6 +48,8 @@
 #include "BKE_global.h"
 #include "BKE_main.h"
 
+#include "BLO_readfile.h"
+
 #include "BLT_translation.h"
 
 #include "IMB_imbuf_types.h"
@@ -64,12 +67,20 @@
 #include "UI_resources.h"
 #include "UI_view2d.h"
 
+#include "WM_api.h"
 #include "WM_types.h"
 
 #include "filelist.h"
 
 #include "file_intern.h"    // own include
 
+/* Dummy helper - we need dynamic tooltips here. */
+static char *file_draw_tooltip_func(bContext *UNUSED(C), void *argN, const char *UNUSED(tip))
+{
+	char *dyn_tooltip = argN;
+	return BLI_strdup(dyn_tooltip);
+}
+
 /* Note: This function uses pixelspace (0, 0, winx, winy), not view2d. 
  * The controls are laid out as follows:
  *
@@ -157,9 +168,9 @@ void file_draw_buttons(const bContext *C, ARegion *ar)
 
 	/* Text input fields for directory and file. */
 	if (available_w > 0) {
-		const struct direntry *file = sfile->files ? filelist_file(sfile->files, params->active_file) : NULL;
+		const struct FileDirEntry *file = sfile->files ? filelist_file(sfile->files, params->active_file) : NULL;
 		int overwrite_alert = file_draw_check_exists(sfile);
-		const bool is_active_dir = file && file->path && BLI_is_dir(file->path);
+		const bool is_active_dir = file && (file->typeflag & FILE_TYPE_FOLDER);
 
 		/* callbacks for operator check functions */
 		UI_block_func_set(block, file_draw_check_cb, NULL, NULL);
@@ -220,8 +231,8 @@ void file_draw_buttons(const bContext *C, ARegion *ar)
 	
 	/* Execute / cancel buttons. */
 	if (loadbutton) {
-		const struct direntry *file = filelist_file(sfile->files, params->active_file);
-		const char *str_exec = (file && file->path && BLI_is_dir(file->path)) ?
+		const struct FileDirEntry *file = sfile->files ? filelist_file(sfile->files, params->active_file) : NULL;
+		const char *str_exec = (file && (file->typeflag & FILE_TYPE_FOLDER)) ?
 		                        /* params->title is already translated! */
 		                        IFACE_("Open Directory") : params->title;
 
@@ -244,44 +255,6 @@ static void draw_tile(int sx, int sy, int width, int height, int colorid, int sh
 }
 
 
-static int get_file_icon(struct direntry *file)
-{
-	if (file->type & S_IFDIR) {
-		if (FILENAME_IS_PARENT(file->relname)) {
-			return ICON_FILE_PARENT;
-		}
-		if (file->flags & FILE_TYPE_APPLICATIONBUNDLE) {
-			return ICON_UGLYPACKAGE;
-		}
-		if (file->flags & FILE_TYPE_BLENDER) {
-			return ICON_FILE_BLEND;
-		}
-		return ICON_FILE_FOLDER;
-	}
-	else if (file->flags & FILE_TYPE_BLENDER)
-		return ICON_FILE_BLEND;
-	else if (file->flags & FILE_TYPE_BLENDER_BACKUP)
-		return ICON_FILE_BACKUP;
-	else if (file->flags & FILE_TYPE_IMAGE)
-		return ICON_FILE_IMAGE;
-	else if (file->flags & FILE_TYPE_MOVIE)
-		return ICON_FILE_MOVIE;
-	else if (file->flags & FILE_TYPE_PYSCRIPT)
-		return ICON_FILE_SCRIPT;
-	else if (file->flags & FILE_TYPE_SOUND)
-		return ICON_FILE_SOUND;
-	else if (file->flags & FILE_TYPE_FTFONT)
-		return ICON_FILE_FONT;
-	else if (file->flags & FILE_TYPE_BTX)
-		return ICON_FILE_BLANK;
-	else if (file->flags & FILE_TYPE_COLLADA)
-		return ICON_FILE_BLANK;
-	else if (file->flags & FILE_TYPE_TEXT)
-		return ICON_FILE_TEXT;
-	else
-		return ICON_FILE_BLANK;
-}
-
 static void file_draw_icon(uiBlock *block, const char *path, int sx, int sy, int icon, int width, int height, bool drag)
 {
 	uiBut *but;
@@ -293,10 +266,12 @@ static void file_draw_icon(uiBlock *block, const char *path, int sx, int sy, int
 	
 	/*if (icon == ICON_FILE_BLANK) alpha = 0.375f;*/
 
-	but = uiDefIconBut(block, UI_BTYPE_LABEL, 0, icon, x, y, width, height, NULL, 0.0f, 0.0f, 0.0f, 0.0f, "");
+	but = uiDefIconBut(block, UI_BTYPE_LABEL, 0, icon, x, y, width, height, NULL, 0.0f, 0.0f, 0.0f, 0.0f, NULL);
+	UI_but_func_tooltip_set(but, file_draw_tooltip_func, BLI_strdup(path));
 
 	if (drag) {
-		UI_but_drag_set_path(but, path, false);
+		/* path is no more static, cannot give it directly to but... */
+		UI_but_drag_set_path(but, BLI_strdup(path), true);
 	}
 }
 
@@ -338,7 +313,9 @@ void file_calc_previews(const bContext *C, ARegion *ar)
 	UI_view2d_totRect_set(v2d, sfile->layout->width, sfile->layout->height);
 }
 
-static void file_draw_preview(uiBlock *block, struct direntry *file, int sx, int sy, ImBuf *imb, FileLayout *layout, bool is_icon, bool drag)
+static void file_draw_preview(
+        uiBlock *block, const char *path, int sx, int sy, const float icon_aspect,
+        ImBuf *imb, const int icon, FileLayout *layout, const bool is_icon, const int typeflags, const bool drag)
 {
 	uiBut *but;
 	float fx, fy;
@@ -348,7 +325,7 @@ static void file_draw_preview(uiBlock *block, struct direntry *file, int sx, int
 	float scaledx, scaledy;
 	float scale;
 	int ex, ey;
-	bool use_dropshadow = !is_icon && (file->flags & FILE_TYPE_IMAGE);
+	bool use_dropshadow = !is_icon && (typeflags & FILE_TYPE_IMAGE);
 
 	BLI_assert(imb != NULL);
 
@@ -394,7 +371,7 @@ static void file_draw_preview(uiBlock *block, struct direntry *file, int sx, int
 	glEnable(GL_BLEND);
 
 	/* the image */
-	if (!is_icon && file->flags & FILE_TYPE_FTFONT) {
+	if (!is_icon && typeflags & FILE_TYPE_FTFONT) {
 		UI_ThemeColor(TH_TEXT);
 	}
 	else {
@@ -402,16 +379,23 @@ static void file_draw_preview(uiBlock *block, struct direntry *file, int sx, int
 	}
 	glaDrawPixelsTexScaled((float)xco, (float)yco, imb->x, imb->y, GL_RGBA, GL_UNSIGNED_BYTE, GL_NEAREST, imb->rect, scale, scale);
 
+	if (icon) {
+		UI_icon_draw_aspect((float)xco, (float)yco, icon, icon_aspect, 1.0f);
+	}
+
 	/* border */
 	if (use_dropshadow) {
 		glColor4f(0.0f, 0.0f, 0.0f, 0.4f);
 		fdrawbox((float)xco, (float)yco, (float)(xco + ex), (float)(yco + ey));
 	}
 
+	but = uiDefBut(block, UI_BTYPE_LABEL, 0, "", xco, yco, ex, ey, NULL, 0.0, 0.0, 0, 0, NULL);
+	UI_but_func_tooltip_set(but, file_draw_tooltip_func, BLI_strdup(path));
+
 	/* dragregion */
 	if (drag) {
-		but = uiDefBut(block, UI_BTYPE_LABEL, 0, "", xco, yco, ex, ey, NULL, 0.0, 0.0, 0, 0, "");
-		UI_but_drag_set_image(but, file->path, get_file_icon(file), imb, scale, false);
+		/* path is no more static, cannot give it directly to but... */
+		UI_but_drag_set_image(but, BLI_strdup(path), icon, imb, scale, true);
 	}
 
 	glDisable(GL_BLEND);
@@ -424,6 +408,7 @@ static void renamebutton_cb(bContext *C, void *UNUSED(arg1), char *oldname)
 	char filename[FILE_MAX + 12];
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = (SpaceFile *)CTX_wm_space_data(C);
+	ScrArea *sa = CTX_wm_area(C);
 	ARegion *ar = CTX_wm_region(C);
 
 	BLI_make_file_string(G.main->name, orgname, sfile->params->dir, oldname);
@@ -435,7 +420,7 @@ static void renamebutton_cb(bContext *C, void *UNUSED(arg1), char *oldname)
 		if (!BLI_exists(newname)) {
 			BLI_rename(orgname, newname);
 			/* to make sure we show what is on disk */
-			ED_fileselect_clear(wm, sfile);
+			ED_fileselect_clear(wm, sa, sfile);
 		}
 
 		ED_region_tag_redraw(ar);
@@ -500,7 +485,8 @@ void file_draw_list(const bContext *C, ARegion *ar)
 	FileLayout *layout = ED_fileselect_get_layout(sfile, ar);
 	View2D *v2d = &ar->v2d;
 	struct FileList *files = sfile->files;
-	struct direntry *file;
+	struct FileDirEntry *file;
+	const char *root = filelist_dir(files);
 	ImBuf *imb;
 	uiBlock *block = UI_block_begin(C, ar, __func__, UI_EMBOSS);
 	int numfiles;
@@ -513,8 +499,11 @@ void file_draw_list(const bContext *C, ARegion *ar)
 	short align;
 	bool do_drag;
 	int column_space = 0.6f * UI_UNIT_X;
+	const bool small_size = SMALL_SIZE_CHECK(params->thumbnail_size);
+	const bool update_stat_strings = small_size != SMALL_SIZE_CHECK(layout->curr_size);
+	const float thumb_icon_aspect = sqrtf(64.0f / (float)(params->thumbnail_size));
 
-	numfiles = filelist_numfiles(files);
+	numfiles = filelist_files_ensure(files);
 	
 	if (params->display != FILE_IMGDISPLAY) {
 
@@ -536,27 +525,61 @@ void file_draw_list(const bContext *C, ARegion *ar)
 		numfiles_layout += layout->columns;
 	}
 
+	filelist_file_cache_slidingwindow_set(files, numfiles_layout);
+
 	textwidth = (FILE_IMGDISPLAY == params->display) ? layout->tile_w : (int)layout->column_widths[COLUMN_NAME];
 	textheight = (int)(layout->textheight * 3.0 / 2.0 + 0.5);
 
 	align = (FILE_IMGDISPLAY == params->display) ? UI_STYLE_TEXT_CENTER : UI_STYLE_TEXT_LEFT;
 
+	if (numfiles > 0) {
+		const bool success = filelist_file_cache_block(files, min_ii(offset + (numfiles_layout / 2), numfiles - 1));
+		BLI_assert(success);
+		UNUSED_VARS_NDEBUG(success);
+
+		filelist_cache_previews_update(files);
+
+		/* Handle preview timer here, since it's filelist_file_cache_block() and filelist_cache_previews_update()
+		 * which controlls previews task. */
+		{
+			const bool previews_running = filelist_cache_previews_running(files);
+//			printf("%s: preview task: %d\n", __func__, previews_running);
+			if (previews_running && !sfile->previews_timer) {
+				sfile->previews_timer = WM_event_add_timer_notifier(CTX_wm_manager(C), CTX_wm_window(C),
+																	NC_SPACE | ND_SPACE_FILE_PREVIEW, 0.01);
+			}
+			if (!previews_running && sfile->previews_timer) {
+				/* Preview is not running, no need to keep generating update events! */
+//				printf("%s: Inactive preview task, sleeping!\n", __func__);
+				WM_event_remove_timer_notifier(CTX_wm_manager(C), CTX_wm_window(C), sfile->previews_timer);
+				sfile->previews_timer = NULL;
+			}
+		}
+	}
+
 	for (i = offset; (i < numfiles) && (i < offset + numfiles_layout); i++) {
+		unsigned int file_selflag;
+		char path[FILE_MAX_LIBEXTRA];
 		ED_fileselect_layout_tilepos(layout, i, &sx, &sy);
 		sx += (int)(v2d->tot.xmin + 0.1f * UI_UNIT_X);
 		sy = (int)(v2d->tot.ymax - sy);
 
 		file = filelist_file(files, i);
+		file_selflag = filelist_entry_select_get(sfile->files, file, CHECK_ALL);
+
+		BLI_join_dirfile(path, sizeof(path), root, file->relpath);
 
 		UI_ThemeColor4(TH_TEXT);
 
 
-		if (!(file->selflag & FILE_SEL_EDITING)) {
-			if ((params->highlight_file == i) || (file->selflag & FILE_SEL_HIGHLIGHTED) || (file->selflag & FILE_SEL_SELECTED)) {
-				int colorid = (file->selflag & FILE_SEL_SELECTED) ? TH_HILITE : TH_BACK;
-				int shade = (params->highlight_file == i) || (file->selflag & FILE_SEL_HIGHLIGHTED) ? 35 : 0;
+		if (!(file_selflag & FILE_SEL_EDITING)) {
+			if ((params->highlight_file == i) || (file_selflag & FILE_SEL_HIGHLIGHTED) ||
+			    (file_selflag & FILE_SEL_SELECTED))
+			{
+				int colorid = (file_selflag & FILE_SEL_SELECTED) ? TH_HILITE : TH_BACK;
+				int shade = (params->highlight_file == i) || (file_selflag & FILE_SEL_HIGHLIGHTED) ? 35 : 0;
 
-				BLI_assert(i > 0 || FILENAME_IS_CURRPAR(file->relname));
+				BLI_assert(i > 0 || FILENAME_IS_CURRPAR(file->relpath));
 
 				draw_tile(sx, sy - 1, layout->tile_w + 4, sfile->layout->tile_h + layout->tile_border_y, colorid, shade);
 			}
@@ -564,26 +587,29 @@ void file_draw_list(const bContext *C, ARegion *ar)
 		UI_draw_roundbox_corner_set(UI_CNR_NONE);
 
 		/* don't drag parent or refresh items */
-		do_drag = !(FILENAME_IS_CURRPAR(file->relname));
+		do_drag = !(FILENAME_IS_CURRPAR(file->relpath));
 
 		if (FILE_IMGDISPLAY == params->display) {
+			const int icon = filelist_geticon(files, i, false);
 			is_icon = 0;
 			imb = filelist_getimage(files, i);
 			if (!imb) {
-				imb = filelist_geticon(files, i);
+				imb = filelist_geticon_image(files, i);
 				is_icon = 1;
 			}
 
-			file_draw_preview(block, file, sx, sy, imb, layout, is_icon, do_drag);
+			file_draw_preview(block, path, sx, sy, thumb_icon_aspect,
+			                  imb, icon, layout, is_icon, file->typeflag, do_drag);
 		}
 		else {
-			file_draw_icon(block, file->path, sx, sy - (UI_UNIT_Y / 6), get_file_icon(file), ICON_DEFAULT_WIDTH_SCALE, ICON_DEFAULT_HEIGHT_SCALE, do_drag);
+			file_draw_icon(block, path, sx, sy - (UI_UNIT_Y / 6), filelist_geticon(files, i, true),
+			               ICON_DEFAULT_WIDTH_SCALE, ICON_DEFAULT_HEIGHT_SCALE, do_drag);
 			sx += ICON_DEFAULT_WIDTH_SCALE + 0.2f * UI_UNIT_X;
 		}
 
 		UI_ThemeColor4(TH_TEXT);
 
-		if (file->selflag & FILE_SEL_EDITING) {
+		if (file_selflag & FILE_SEL_EDITING) {
 			uiBut *but;
 			short width;
 
@@ -591,9 +617,7 @@ void file_draw_list(const bContext *C, ARegion *ar)
 				width = layout->tile_w - (ICON_DEFAULT_WIDTH_SCALE + 0.2f * UI_UNIT_X);
 			}
 			else if (params->display == FILE_LONGDISPLAY) {
-				width = layout->column_widths[COLUMN_NAME]  + layout->column_widths[COLUMN_MODE1] +
-				        layout->column_widths[COLUMN_MODE2] + layout->column_widths[COLUMN_MODE3] +
-				        (column_space * 3.5f);
+				width = layout->column_widths[COLUMN_NAME] + (column_space * 3.5f);
 			}
 			else {
 				BLI_assert(params->display == FILE_IMGDISPLAY);
@@ -601,53 +625,51 @@ void file_draw_list(const bContext *C, ARegion *ar)
 			}
 
 			but = uiDefBut(block, UI_BTYPE_TEXT, 1, "", sx, sy - layout->tile_h - 0.15f * UI_UNIT_X,
-			               width, textheight, sfile->params->renameedit, 1.0f, (float)sizeof(sfile->params->renameedit), 0, 0, "");
+			               width, textheight, sfile->params->renameedit, 1.0f,
+			               (float)sizeof(sfile->params->renameedit), 0, 0, "");
 			UI_but_func_rename_set(but, renamebutton_cb, file);
 			UI_but_flag_enable(but, UI_BUT_NO_UTF8); /* allow non utf8 names */
 			UI_but_flag_disable(but, UI_BUT_UNDO);
 			if (false == UI_but_active_only(C, ar, block, but)) {
-				file->selflag &= ~FILE_SEL_EDITING;
+				file_selflag = filelist_entry_select_set(
+				                   sfile->files, file, FILE_SEL_REMOVE, FILE_SEL_EDITING, CHECK_ALL);
 			}
 		}
 
-		if (!(file->selflag & FILE_SEL_EDITING)) {
+		if (!(file_selflag& FILE_SEL_EDITING)) {
 			int tpos = (FILE_IMGDISPLAY == params->display) ? sy - layout->tile_h + layout->textheight : sy;
-			file_draw_string(sx + 1, tpos, file->relname, (float)textwidth, textheight, align);
+			file_draw_string(sx + 1, tpos, file->name, (float)textwidth, textheight, align);
 		}
 
 		if (params->display == FILE_SHORTDISPLAY) {
 			sx += (int)layout->column_widths[COLUMN_NAME] + column_space;
-			if (!(file->type & S_IFDIR)) {
-				file_draw_string(sx, sy, file->size, layout->column_widths[COLUMN_SIZE], layout->tile_h, align);
+			if (!(file->typeflag & FILE_TYPE_DIR)) {
+				if ((file->entry->size_str[0] == '\0') || update_stat_strings) {
+					BLI_filelist_entry_size_to_string(NULL, file->entry->size, small_size, file->entry->size_str);
+				}
+				file_draw_string(
+				            sx, sy, file->entry->size_str, layout->column_widths[COLUMN_SIZE], layout->tile_h, align);
 				sx += (int)layout->column_widths[COLUMN_SIZE] + column_space;
 			}
 		}
 		else if (params->display == FILE_LONGDISPLAY) {
 			sx += (int)layout->column_widths[COLUMN_NAME] + column_space;
 
-#ifndef WIN32
-			/* rwx rwx rwx */
-			file_draw_string(sx, sy, file->mode1, layout->column_widths[COLUMN_MODE1], layout->tile_h, align); 
-			sx += layout->column_widths[COLUMN_MODE1] + column_space;
-
-			file_draw_string(sx, sy, file->mode2, layout->column_widths[COLUMN_MODE2], layout->tile_h, align);
-			sx += layout->column_widths[COLUMN_MODE2] + column_space;
-
-			file_draw_string(sx, sy, file->mode3, layout->column_widths[COLUMN_MODE3], layout->tile_h, align);
-			sx += layout->column_widths[COLUMN_MODE3] + column_space;
-
-			file_draw_string(sx, sy, file->owner, layout->column_widths[COLUMN_OWNER], layout->tile_h, align);
-			sx += layout->column_widths[COLUMN_OWNER] + column_space;
-#endif
-
-			file_draw_string(sx, sy, file->date, layout->column_widths[COLUMN_DATE], layout->tile_h, align);
+			if ((file->entry->date_str[0] == '\0') || update_stat_strings) {
+				BLI_filelist_entry_datetime_to_string(
+				            NULL, file->entry->time, small_size, file->entry->time_str, file->entry->date_str);
+			}
+			file_draw_string(sx, sy, file->entry->date_str, layout->column_widths[COLUMN_DATE], layout->tile_h, align);
 			sx += (int)layout->column_widths[COLUMN_DATE] + column_space;
-
-			file_draw_string(sx, sy, file->time, layout->column_widths[COLUMN_TIME], layout->tile_h, align);
+			file_draw_string(sx, sy, file->entry->time_str, layout->column_widths[COLUMN_TIME], layout->tile_h, align);
 			sx += (int)layout->column_widths[COLUMN_TIME] + column_space;
 
-			if (!(file->type & S_IFDIR)) {
-				file_draw_string(sx, sy, file->size, layout->column_widths[COLUMN_SIZE], layout->tile_h, align);
+			if (!(file->typeflag & FILE_TYPE_DIR)) {
+				if ((file->entry->size_str[0] == '\0') || update_stat_strings) {
+					BLI_filelist_entry_size_to_string(NULL, file->entry->size, small_size, file->entry->size_str);
+				}
+				file_draw_string(
+				            sx, sy, file->entry->size_str, layout->column_widths[COLUMN_SIZE], layout->tile_h, align);
 				sx += (int)layout->column_widths[COLUMN_SIZE] + column_space;
 			}
 		}
@@ -656,4 +678,5 @@ void file_draw_list(const bContext *C, ARegion *ar)
 	UI_block_end(C, block);
 	UI_block_draw(C, block);
 
+	layout->curr_size = params->thumbnail_size;
 }
diff --git a/source/blender/editors/space_file/file_intern.h b/source/blender/editors/space_file/file_intern.h
index b24780c6e05..baafefab1f6 100644
--- a/source/blender/editors/space_file/file_intern.h
+++ b/source/blender/editors/space_file/file_intern.h
@@ -48,6 +48,8 @@ struct ARegion *file_tools_region(struct ScrArea *sa);
 #define IMASEL_BUTTONS_HEIGHT (UI_UNIT_Y * 2)
 #define IMASEL_BUTTONS_MARGIN (UI_UNIT_Y / 6)
 
+#define SMALL_SIZE_CHECK(_size) ((_size) < 64)  /* Related to FileSelectParams.thumbnail_size. */
+
 void file_draw_buttons(const bContext *C, ARegion *ar);
 void file_calc_previews(const bContext *C, ARegion *ar);
 void file_draw_list(const bContext *C, ARegion *ar);
diff --git a/source/blender/editors/space_file/file_ops.c b/source/blender/editors/space_file/file_ops.c
index 6bbde1e1c17..4e56b5b2d7d 100644
--- a/source/blender/editors/space_file/file_ops.c
+++ b/source/blender/editors/space_file/file_ops.c
@@ -99,9 +99,9 @@ static void file_deselect_all(SpaceFile *sfile, unsigned int flag)
 {
 	FileSelection sel;
 	sel.first = 0;
-	sel.last = filelist_numfiles(sfile->files) - 1;
+	sel.last = filelist_files_ensure(sfile->files) - 1;
 	
-	filelist_select(sfile->files, &sel, FILE_SEL_REMOVE, flag, CHECK_ALL);
+	filelist_entries_select_index_range_set(sfile->files, &sel, FILE_SEL_REMOVE, flag, CHECK_ALL);
 }
 
 typedef enum FileSelect { 
@@ -139,7 +139,7 @@ static FileSelection file_selection_get(bContext *C, const rcti *rect, bool fill
 {
 	ARegion *ar = CTX_wm_region(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
-	int numfiles = filelist_numfiles(sfile->files);
+	int numfiles = filelist_files_ensure(sfile->files);
 	FileSelection sel;
 
 	sel = find_file_mouse_rect(sfile, ar, rect);
@@ -152,7 +152,7 @@ static FileSelection file_selection_get(bContext *C, const rcti *rect, bool fill
 	if (fill && (sel.last >= 0) && (sel.last < numfiles) ) {
 		int f = sel.last;
 		while (f >= 0) {
-			if (filelist_is_selected(sfile->files, f, CHECK_ALL) )
+			if (filelist_entry_select_index_get(sfile->files, f, CHECK_ALL) )
 				break;
 			f--;
 		}
@@ -168,8 +168,8 @@ static FileSelect file_select_do(bContext *C, int selected_idx, bool do_diropen)
 	FileSelect retval = FILE_SELECT_NOTHING;
 	SpaceFile *sfile = CTX_wm_space_file(C);
 	FileSelectParams *params = ED_fileselect_get_params(sfile);
-	int numfiles = filelist_numfiles(sfile->files);
-	struct direntry *file;
+	int numfiles = filelist_files_ensure(sfile->files);
+	const FileDirEntry *file;
 
 	/* make the selected file active */
 	if ((selected_idx >= 0) &&
@@ -177,27 +177,33 @@ static FileSelect file_select_do(bContext *C, int selected_idx, bool do_diropen)
 	    (file = filelist_file(sfile->files, selected_idx)))
 	{
 		params->highlight_file = selected_idx;
-		sfile->params->active_file = selected_idx;
+		params->active_file = selected_idx;
 
-		if (S_ISDIR(file->type)) {
-			const bool is_parent_dir = FILENAME_IS_PARENT(file->relname);
+		if (file->typeflag & FILE_TYPE_DIR) {
+			const bool is_parent_dir = FILENAME_IS_PARENT(file->relpath);
 
 			if (do_diropen == false) {
 				params->file[0] = '\0';
 				retval = FILE_SELECT_DIR;
 			}
 			/* the path is too long and we are not going up! */
-			else if (!is_parent_dir && strlen(params->dir) + strlen(file->relname) >= FILE_MAX) {
+			else if (!is_parent_dir && strlen(params->dir) + strlen(file->relpath) >= FILE_MAX) {
 				// XXX error("Path too long, cannot enter this directory");
 			}
 			else {
 				if (is_parent_dir) {
 					/* avoids /../../ */
 					BLI_parent_dir(params->dir);
+
+					if (params->recursion_level > 1) {
+						/* Disable 'dirtree' recursion when going up in tree. */
+						params->recursion_level = 0;
+						filelist_setrecursion(sfile->files, params->recursion_level);
+					}
 				}
 				else {
 					BLI_cleanup_dir(G.main->name, params->dir);
-					strcat(params->dir, file->relname);
+					strcat(params->dir, file->relpath);
 					BLI_add_slash(params->dir);
 				}
 
@@ -218,11 +224,12 @@ static FileSelect file_select_do(bContext *C, int selected_idx, bool do_diropen)
  */
 static bool file_is_any_selected(struct FileList *files)
 {
-	const int numfiles = filelist_numfiles(files);
+	const int numfiles = filelist_files_ensure(files);
 	int i;
 
+	/* Is any file selected ? */
 	for (i = 0; i < numfiles; ++i) {
-		if (filelist_is_selected(files, i, CHECK_ALL)) {
+		if (filelist_entry_select_index_get(files, i, CHECK_ALL)) {
 			return true;
 		}
 	}
@@ -239,7 +246,7 @@ static FileSelect file_select(bContext *C, const rcti *rect, FileSelType select,
 	const FileCheckType check_type = (sfile->params->flag & FILE_DIRSEL_ONLY) ? CHECK_DIRS : CHECK_ALL;
 	
 	/* flag the files as selected in the filelist */
-	filelist_select(sfile->files, &sel, select, FILE_SEL_SELECTED, check_type);
+	filelist_entries_select_index_range_set(sfile->files, &sel, select, FILE_SEL_SELECTED, check_type);
 	
 	/* Don't act on multiple selected files */
 	if (sel.first != sel.last) select = 0;
@@ -247,7 +254,7 @@ static FileSelect file_select(bContext *C, const rcti *rect, FileSelType select,
 	/* Do we have a valid selection and are we actually selecting */
 	if ((sel.last >= 0) && (select != FILE_SEL_REMOVE)) {
 		/* Check last selection, if selected, act on the file or dir */
-		if (filelist_is_selected(sfile->files, sel.last, check_type)) {
+		if (filelist_entry_select_index_get(sfile->files, sel.last, check_type)) {
 			retval = file_select_do(C, sel.last, do_diropen);
 		}
 	}
@@ -305,25 +312,24 @@ static int file_border_select_modal(bContext *C, wmOperator *op, const wmEvent *
 	result = WM_border_select_modal(C, op, event);
 
 	if (result == OPERATOR_RUNNING_MODAL) {
-
 		WM_operator_properties_border_to_rcti(op, &rect);
 
 		BLI_rcti_isect(&(ar->v2d.mask), &rect, &rect);
 
 		sel = file_selection_get(C, &rect, 0);
-		if ( (sel.first != params->sel_first) || (sel.last != params->sel_last) ) {
+		if ((sel.first != params->sel_first) || (sel.last != params->sel_last)) {
 			int idx;
 
 			file_deselect_all(sfile, FILE_SEL_HIGHLIGHTED);
-			filelist_select(sfile->files, &sel, FILE_SEL_ADD, FILE_SEL_HIGHLIGHTED, CHECK_ALL);
+			filelist_entries_select_index_range_set(sfile->files, &sel, FILE_SEL_ADD, FILE_SEL_HIGHLIGHTED, CHECK_ALL);
 			WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
 
 			for (idx = sel.last; idx >= 0; idx--) {
-				struct direntry *file = filelist_file(sfile->files, idx);
+				const FileDirEntry *file = filelist_file(sfile->files, idx);
 
 				/* dont highlight readonly file (".." or ".") on border select */
-				if (FILENAME_IS_CURRPAR(file->relname)) {
-					file->selflag &= ~FILE_SEL_HIGHLIGHTED;
+				if (FILENAME_IS_CURRPAR(file->relpath)) {
+					filelist_entry_select_set(sfile->files, file, FILE_SEL_REMOVE, FILE_SEL_HIGHLIGHTED, CHECK_ALL);
 				}
 
 				/* make sure highlight_file is no readonly file */
@@ -366,7 +372,7 @@ static int file_border_select_exec(bContext *C, wmOperator *op)
 	ret = file_select(C, &rect, select ? FILE_SEL_ADD : FILE_SEL_REMOVE, false, false);
 
 	/* unselect '..' parent entry - it's not supposed to be selected if more than one file is selected */
-	filelist_select_file(sfile->files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
+	filelist_entry_select_index_set(sfile->files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
 
 	if (FILE_SELECT_DIR == ret) {
 		WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
@@ -416,8 +422,9 @@ static int file_select_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 
 	if (sfile && sfile->params) {
 		int idx = sfile->params->highlight_file;
+		int numfiles = filelist_files_ensure(sfile->files);
 
-		if (idx >= 0) {
+		if ((idx >= 0) && (idx < numfiles)) {
 			/* single select, deselect all selected first */
 			if (!extend) {
 				file_deselect_all(sfile, FILE_SEL_SELECTED);
@@ -429,7 +436,7 @@ static int file_select_invoke(bContext *C, wmOperator *op, const wmEvent *event)
 
 	if (extend) {
 		/* unselect '..' parent entry - it's not supposed to be selected if more than one file is selected */
-		filelist_select_file(sfile->files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
+		filelist_entry_select_index_set(sfile->files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
 	}
 
 	if (FILE_SELECT_DIR == ret)
@@ -484,12 +491,13 @@ static bool file_walk_select_selection_set(
 
 	if (has_selection) {
 		if (extend &&
-		    filelist_is_selected(files, active_old, FILE_SEL_SELECTED) &&
-		    filelist_is_selected(files, active_new, FILE_SEL_SELECTED))
+		    filelist_entry_select_index_get(files, active_old, FILE_SEL_SELECTED) &&
+		    filelist_entry_select_index_get(files, active_new, FILE_SEL_SELECTED))
 		{
 			/* conditions for deselecting: initial file is selected, new file is
 			 * selected and either other_side isn't selected/found or we use fill */
-			deselect = (fill || other_site == -1 || !filelist_is_selected(files, other_site, FILE_SEL_SELECTED));
+				deselect = (fill || other_site == -1 ||
+				            !filelist_entry_select_index_get(files, other_site, FILE_SEL_SELECTED));
 
 			/* don't change highlight_file here since we either want to deselect active or we want to
 			 * walk through a block of selected files without selecting/deselecting anything */
@@ -527,7 +535,7 @@ static bool file_walk_select_selection_set(
 		params->highlight_file = params->active_file;
 
 		/* unselect '..' parent entry - it's not supposed to be selected if more than one file is selected */
-		filelist_select_file(files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
+		filelist_entry_select_index_set(files, 0, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
 	}
 	else {
 		/* deselect all first */
@@ -548,15 +556,15 @@ static bool file_walk_select_selection_set(
 		}
 
 		/* fill selection between last and first selected file */
-		filelist_select(
+		filelist_entries_select_index_range_set(
 		            files, &sel, deselect ? FILE_SEL_REMOVE : FILE_SEL_ADD, FILE_SEL_SELECTED, CHECK_ALL);
 		/* entire sel is cleared here, so select active again */
 		if (deselect) {
-			filelist_select_file(files, active, FILE_SEL_ADD, FILE_SEL_SELECTED, CHECK_ALL);
+			filelist_entry_select_index_set(files, active, FILE_SEL_ADD, FILE_SEL_SELECTED, CHECK_ALL);
 		}
 	}
 	else {
-		filelist_select_file(
+		filelist_entry_select_index_set(
 		            files, active, deselect ? FILE_SEL_REMOVE : FILE_SEL_ADD, FILE_SEL_SELECTED, CHECK_ALL);
 	}
 
@@ -576,7 +584,7 @@ static bool file_walk_select_do(
         const bool extend, const bool fill)
 {
 	struct FileList *files = sfile->files;
-	const int numfiles = filelist_numfiles(files);
+	const int numfiles = filelist_files_ensure(files);
 	const bool has_selection = file_is_any_selected(files);
 	const int active_old = params->active_file;
 	int active_new = -1;
@@ -692,7 +700,7 @@ static int file_select_all_exec(bContext *C, wmOperator *UNUSED(op))
 	ScrArea *sa = CTX_wm_area(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
 	FileSelection sel;
-	const int numfiles = filelist_numfiles(sfile->files);
+	const int numfiles = filelist_files_ensure(sfile->files);
 	const bool has_selection = file_is_any_selected(sfile->files);
 
 	sel.first = 0; 
@@ -700,18 +708,18 @@ static int file_select_all_exec(bContext *C, wmOperator *UNUSED(op))
 
 	/* select all only if previously no file was selected */
 	if (has_selection) {
-		filelist_select(sfile->files, &sel, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
+		filelist_entries_select_index_range_set(sfile->files, &sel, FILE_SEL_REMOVE, FILE_SEL_SELECTED, CHECK_ALL);
 		sfile->params->active_file = -1;
 	}
 	else {
 		const FileCheckType check_type = (sfile->params->flag & FILE_DIRSEL_ONLY) ? CHECK_DIRS : CHECK_FILES;
 		int i;
 
-		filelist_select(sfile->files, &sel, FILE_SEL_ADD, FILE_SEL_SELECTED, check_type);
+		filelist_entries_select_index_range_set(sfile->files, &sel, FILE_SEL_ADD, FILE_SEL_SELECTED, check_type);
 
 		/* set active_file to first selected */
 		for (i = 0; i < numfiles; i++) {
-			if (filelist_is_selected(sfile->files, i, check_type)) {
+			if (filelist_entry_select_index_get(sfile->files, i, check_type)) {
 				sfile->params->active_file = i;
 				break;
 			}
@@ -1029,7 +1037,7 @@ int file_highlight_set(SpaceFile *sfile, ARegion *ar, int mx, int my)
 
 	if (sfile == NULL || sfile->files == NULL) return 0;
 
-	numfiles = filelist_numfiles(sfile->files);
+	numfiles = filelist_files_ensure(sfile->files);
 	params = ED_fileselect_get_params(sfile);
 
 	origfile = params->highlight_file;
@@ -1143,17 +1151,17 @@ void file_sfile_to_operator(wmOperator *op, SpaceFile *sfile, char *filepath)
 	/* this is called on operators check() so clear collections first since
 	 * they may be already set. */
 	{
-		int i, numfiles = filelist_numfiles(sfile->files);
+		int i, numfiles = filelist_files_ensure(sfile->files);
 
 		if ((prop = RNA_struct_find_property(op->ptr, "files"))) {
 			PointerRNA itemptr;
 			int num_files = 0;
 			RNA_property_collection_clear(op->ptr, prop);
 			for (i = 0; i < numfiles; i++) {
-				if (filelist_is_selected(sfile->files, i, CHECK_FILES)) {
-					struct direntry *file = filelist_file(sfile->files, i);
+				if (filelist_entry_select_index_get(sfile->files, i, CHECK_FILES)) {
+					FileDirEntry *file = filelist_file(sfile->files, i);
 					RNA_property_collection_add(op->ptr, prop, &itemptr);
-					RNA_string_set(&itemptr, "name", file->relname);
+					RNA_string_set(&itemptr, "name", file->relpath);
 					num_files++;
 				}
 			}
@@ -1169,10 +1177,10 @@ void file_sfile_to_operator(wmOperator *op, SpaceFile *sfile, char *filepath)
 			int num_dirs = 0;
 			RNA_property_collection_clear(op->ptr, prop);
 			for (i = 0; i < numfiles; i++) {
-				if (filelist_is_selected(sfile->files, i, CHECK_DIRS)) {
-					struct direntry *file = filelist_file(sfile->files, i);
+				if (filelist_entry_select_index_get(sfile->files, i, CHECK_DIRS)) {
+					FileDirEntry *file = filelist_file(sfile->files, i);
 					RNA_property_collection_add(op->ptr, prop, &itemptr);
-					RNA_string_set(&itemptr, "name", file->relname);
+					RNA_string_set(&itemptr, "name", file->relpath);
 					num_dirs++;
 				}
 			}
@@ -1262,19 +1270,17 @@ int file_exec(bContext *C, wmOperator *exec_op)
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
-	const struct direntry *file = filelist_file(sfile->files, sfile->params->active_file);
+	const struct FileDirEntry *file = filelist_file(sfile->files, sfile->params->active_file);
 	char filepath[FILE_MAX];
 
 	/* directory change */
-	if (file && S_ISDIR(file->type)) {
-		BLI_assert(file->path == NULL || STRPREFIX(file->path, sfile->params->dir));
-
-		if (FILENAME_IS_PARENT(file->relname)) {
+	if (file && (file->typeflag & FILE_TYPE_DIR)) {
+		if (FILENAME_IS_PARENT(file->relpath)) {
 			BLI_parent_dir(sfile->params->dir);
 		}
-		else if (file->relname) {
+		else if (file->relpath) {
 			BLI_cleanup_dir(G.main->name, sfile->params->dir);
-			strcat(sfile->params->dir, file->relname);
+			strcat(sfile->params->dir, file->relpath);
 			BLI_add_slash(sfile->params->dir);
 		}
 
@@ -1287,10 +1293,11 @@ int file_exec(bContext *C, wmOperator *exec_op)
 		/* when used as a macro, for doubleclick, 
 		 * to prevent closing when doubleclicking on .. item */
 		if (RNA_boolean_get(exec_op->ptr, "need_active")) {
+			const int numfiles = filelist_files_ensure(sfile->files);
 			int i, active = 0;
 			
-			for (i = 0; i < filelist_numfiles(sfile->files); i++) {
-				if (filelist_is_selected(sfile->files, i, CHECK_ALL)) {
+			for (i = 0; i < numfiles; i++) {
+				if (filelist_entry_select_index_get(sfile->files, i, CHECK_ALL)) {
 					active = 1;
 					break;
 				}
@@ -1358,6 +1365,11 @@ int file_parent_exec(bContext *C, wmOperator *UNUSED(unused))
 			else {
 				ED_file_change_dir(C, true);
 			}
+			if (sfile->params->recursion_level > 1) {
+				/* Disable 'dirtree' recursion when going up in tree. */
+				sfile->params->recursion_level = 0;
+				filelist_setrecursion(sfile->files, sfile->params->recursion_level);
+			}
 			WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
 		}
 	}
@@ -1384,9 +1396,10 @@ static int file_refresh_exec(bContext *C, wmOperator *UNUSED(unused))
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
+	ScrArea *sa = CTX_wm_area(C);
 	struct FSMenu *fsmenu = ED_fsmenu_get();
 
-	ED_fileselect_clear(wm, sfile);
+	ED_fileselect_clear(wm, sa, sfile);
 
 	/* refresh system directory menu */
 	fsmenu_refresh_system_category(fsmenu);
@@ -1476,11 +1489,11 @@ static int file_smoothscroll_invoke(bContext *C, wmOperator *UNUSED(op), const w
 	if (sfile->smoothscroll_timer == NULL || sfile->smoothscroll_timer != event->customdata)
 		return OPERATOR_PASS_THROUGH;
 	
-	numfiles = filelist_numfiles(sfile->files);
+	numfiles = filelist_files_ensure(sfile->files);
 
 	/* check if we are editing a name */
 	for (i = 0; i < numfiles; ++i) {
-		if (filelist_is_selected(sfile->files, i, CHECK_ALL) ) {
+		if (filelist_entry_select_index_get(sfile->files, i, CHECK_ALL) ) {
 			edit_idx = i;
 			break;
 		}
@@ -1603,6 +1616,7 @@ int file_directory_new_exec(bContext *C, wmOperator *op)
 
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
+	ScrArea *sa = CTX_wm_area(C);
 	
 	if (!sfile->params) {
 		BKE_report(op->reports, RPT_WARNING, "No parent directory given");
@@ -1655,7 +1669,7 @@ int file_directory_new_exec(bContext *C, wmOperator *op)
 	sfile->scroll_offset = 0;
 
 	/* reload dir to make sure we're seeing what's in the directory */
-	ED_fileselect_clear(wm, sfile);
+	ED_fileselect_clear(wm, sa, sfile);
 
 	if (RNA_boolean_get(op->ptr, "open")) {
 		BLI_strncpy(sfile->params->dir, path, sizeof(sfile->params->dir));
@@ -1876,10 +1890,11 @@ static int file_hidedot_exec(bContext *C, wmOperator *UNUSED(unused))
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
+	ScrArea *sa = CTX_wm_area(C);
 	
 	if (sfile->params) {
 		sfile->params->flag ^= FILE_HIDE_DOT;
-		ED_fileselect_clear(wm, sfile);
+		ED_fileselect_clear(wm, sa, sfile);
 		WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
 	}
 	
@@ -1989,11 +2004,11 @@ static int file_rename_exec(bContext *C, wmOperator *UNUSED(op))
 	
 	if (sfile->params) {
 		int idx = sfile->params->highlight_file;
-		int numfiles = filelist_numfiles(sfile->files);
+		int numfiles = filelist_files_ensure(sfile->files);
 		if ((0 <= idx) && (idx < numfiles)) {
-			struct direntry *file = filelist_file(sfile->files, idx);
-			filelist_select_file(sfile->files, idx, FILE_SEL_ADD, FILE_SEL_EDITING, CHECK_ALL);
-			BLI_strncpy(sfile->params->renameedit, file->relname, FILE_MAXFILE);
+			FileDirEntry *file = filelist_file(sfile->files, idx);
+			filelist_entry_select_index_set(sfile->files, idx, FILE_SEL_ADD, FILE_SEL_EDITING, CHECK_ALL);
+			BLI_strncpy(sfile->params->renameedit, file->relpath, FILE_MAXFILE);
 			sfile->params->renamefile[0] = '\0';
 		}
 		ED_area_tag_redraw(sa);
@@ -2005,29 +2020,34 @@ static int file_rename_exec(bContext *C, wmOperator *UNUSED(op))
 
 static int file_rename_poll(bContext *C)
 {
-	int poll = ED_operator_file_active(C);
+	bool poll = ED_operator_file_active(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
 
 	if (sfile && sfile->params) {
 		int idx = sfile->params->highlight_file;
+		int numfiles = filelist_files_ensure(sfile->files);
 
-		if (idx >= 0) {
-			struct direntry *file = filelist_file(sfile->files, idx);
-			if (FILENAME_IS_CURRPAR(file->relname)) {
-				poll = 0;
+		if ((0 <= idx) && (idx < numfiles)) {
+			FileDirEntry *file = filelist_file(sfile->files, idx);
+			if (FILENAME_IS_CURRPAR(file->relpath)) {
+				poll = false;
 			}
 		}
 
 		if (sfile->params->highlight_file < 0) {
-			poll = 0;
+			poll = false;
 		}
 		else {
 			char dir[FILE_MAX];
-			if (filelist_islibrary(sfile->files, dir, NULL)) poll = 0;
+			if (filelist_islibrary(sfile->files, dir, NULL)) {
+				poll = false;
+			}
 		}
 	}
-	else
-		poll = 0;
+	else {
+		poll = false;
+	}
+
 	return poll;
 }
 
@@ -2051,13 +2071,13 @@ static int file_delete_poll(bContext *C)
 
 	if (sfile && sfile->params) {
 		char dir[FILE_MAX];
-		int numfiles = filelist_numfiles(sfile->files);
+		int numfiles = filelist_files_ensure(sfile->files);
 		int i;
 		int num_selected = 0;
 
 		if (filelist_islibrary(sfile->files, dir, NULL)) poll = 0;
 		for (i = 0; i < numfiles; i++) {
-			if (filelist_is_selected(sfile->files, i, CHECK_FILES)) {
+			if (filelist_entry_select_index_get(sfile->files, i, CHECK_FILES)) {
 				num_selected++;
 			}
 		}
@@ -2076,19 +2096,20 @@ int file_delete_exec(bContext *C, wmOperator *UNUSED(op))
 	char str[FILE_MAX];
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
-	struct direntry *file;	
-	int numfiles = filelist_numfiles(sfile->files);
+	ScrArea *sa = CTX_wm_area(C);
+	FileDirEntry *file;
+	int numfiles = filelist_files_ensure(sfile->files);
 	int i;
 
 	for (i = 0; i < numfiles; i++) {
-		if (filelist_is_selected(sfile->files, i, CHECK_FILES)) {
+		if (filelist_entry_select_index_get(sfile->files, i, CHECK_FILES)) {
 			file = filelist_file(sfile->files, i);
-			BLI_make_file_string(G.main->name, str, sfile->params->dir, file->relname);
+			BLI_make_file_string(G.main->name, str, sfile->params->dir, file->relpath);
 			BLI_delete(str, false, false);
 		}
 	}
 	
-	ED_fileselect_clear(wm, sfile);
+	ED_fileselect_clear(wm, sa, sfile);
 	WM_event_add_notifier(C, NC_SPACE | ND_SPACE_FILE_LIST, NULL);
 	
 	return OPERATOR_FINISHED;
diff --git a/source/blender/editors/space_file/filelist.c b/source/blender/editors/space_file/filelist.c
index 21a072d0adf..02b31b494c2 100644
--- a/source/blender/editors/space_file/filelist.c
+++ b/source/blender/editors/space_file/filelist.c
@@ -35,6 +35,8 @@
 #include <stdlib.h>
 #include <math.h>
 #include <string.h>
+#include <sys/stat.h>
+#include <time.h>
 
 #ifndef WIN32
 #  include <unistd.h>
@@ -45,9 +47,16 @@
 #include "MEM_guardedalloc.h"
 
 #include "BLI_blenlib.h"
+#include "BLI_fileops.h"
 #include "BLI_fileops_types.h"
 #include "BLI_fnmatch.h"
+#include "BLI_ghash.h"
+#include "BLI_hash_md5.h"
 #include "BLI_linklist.h"
+#include "BLI_math.h"
+#include "BLI_stack.h"
+#include "BLI_task.h"
+#include "BLI_threads.h"
 #include "BLI_utildefines.h"
 
 #ifdef WIN32
@@ -60,13 +69,13 @@
 #include "BKE_icons.h"
 #include "BKE_idcode.h"
 #include "BKE_main.h"
-#include "BKE_report.h"
 #include "BLO_readfile.h"
 
 #include "DNA_space_types.h"
 
 #include "ED_datafiles.h"
 #include "ED_fileselect.h"
+#include "ED_screen.h"
 
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
@@ -78,6 +87,9 @@
 #include "WM_types.h"
 
 #include "UI_resources.h"
+#include "UI_interface_icons.h"
+
+#include "atomic_ops.h"
 
 #include "filelist.h"
 
@@ -194,49 +206,128 @@ ListBase *folderlist_duplicate(ListBase *folderlist)
 
 /* ------------------FILELIST------------------------ */
 
-struct FileList;
+typedef struct FileListInternEntry {
+	struct FileListInternEntry *next, *prev;
+
+	char uuid[16];  /* ASSET_UUID_LENGTH */
+
+	int typeflag;  /* eFileSel_File_Types */
+	int blentype;  /* ID type, in case typeflag has FILE_TYPE_BLENDERLIB set. */
+
+	char *relpath;
+	char *name;  /* not striclty needed, but used during sorting, avoids to have to recompute it there... */
+
+	BLI_stat_t st;
+} FileListInternEntry;
+
+typedef struct FileListIntern {
+	ListBase entries;  /* FileListInternEntry items. */
+	FileListInternEntry **filtered;
+
+	char curr_uuid[16];  /* Used to generate uuid during internal listing. */
+} FileListIntern;
+
+#define FILELIST_ENTRYCACHESIZE_DEFAULT 1024  /* Keep it a power of two! */
+typedef struct FileListEntryCache {
+	size_t size;  /* The size of the cache... */
+
+	int flags;
+
+	/* Block cache: all entries between start and end index. used for part of the list on diplay. */
+	FileDirEntry **block_entries;
+	int block_start_index, block_end_index, block_center_index, block_cursor;
+
+	/* Misc cache: random indices, FIFO behavior.
+	 * Note: Not 100% sure we actually need that, time will say. */
+	int misc_cursor;
+	int *misc_entries_indices;
+	GHash *misc_entries;
+
+	/* Allows to quickly get a cached entry from its UUID. */
+	GHash *uuids;
 
-typedef struct FileImage {
-	struct FileImage *next, *prev;
+	/* Previews handling. */
+	TaskPool *previews_pool;
+	ThreadQueue *previews_todo;
+	ThreadQueue *previews_done;
+	double previews_timestamp;
+	int previews_pending;
+} FileListEntryCache;
+
+/* FileListCache.flags */
+enum {
+	FLC_IS_INIT              = 1 << 0,
+	FLC_PREVIEWS_ACTIVE      = 1 << 1,
+};
+
+typedef struct FileListEntryPreview {
 	char path[FILE_MAX];
 	unsigned int flags;
 	int index;
-	short done;
 	ImBuf *img;
-} FileImage;
+} FileListEntryPreview;
 
 typedef struct FileListFilter {
-	bool hide_dot;
-	bool hide_parent;
 	unsigned int filter;
+	unsigned int filter_id;
 	char filter_glob[64];
 	char filter_search[66];  /* + 2 for heading/trailing implicit '*' wildcards. */
+	short flags;
 } FileListFilter;
 
+/* FileListFilter.flags */
+enum {
+	FLF_HIDE_DOT     = 1 << 0,
+	FLF_HIDE_PARENT  = 1 << 1,
+	FLF_HIDE_LIB_DIR = 1 << 2,
+};
+
 typedef struct FileList {
-	struct direntry *filelist;
-	int numfiles;
-	char dir[FILE_MAX];
+	FileDirEntryArr filelist;
+
 	short prv_w;
 	short prv_h;
 
-	bool changed;
+	short flags;
 
 	short sort;
-	bool need_sorting;
 
 	FileListFilter filter_data;
-	int *fidx;  /* Also used to detect when we need to filter! */
-	int numfiltered;
 
-	bool need_thumbnails;
+	struct FileListIntern filelist_intern;
+
+	struct FileListEntryCache filelist_cache;
+
+	/* We need to keep those info outside of actual filelist items, because those are no more persistent
+	 * (only generated on demand, and freed as soon as possible).
+	 * Persistent part (mere list of paths + stat info) is kept as small as possible, and filebrowser-agnostic.
+	 */
+	GHash *selection_state;
+
+	short max_recursion;
+	short recursion_level;
 
 	struct BlendHandle *libfiledata;
 
-	void (*readf)(struct FileList *);
-	bool (*filterf)(struct direntry *, const char *, FileListFilter *);
+	/* Set given path as root directory, may change given string in place to a valid value. */
+	void (*checkdirf)(struct FileList *, char *);
+
+	/* Fill filelist (to be called by read job). */
+	void (*read_jobf)(struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
+
+	/* Filter an entry of current filelist. */
+	bool (*filterf)(struct FileListInternEntry *, const char *, FileListFilter *);
 } FileList;
 
+/* FileList.flags */
+enum {
+	FL_FORCE_RESET    = 1 << 0,
+	FL_IS_READY       = 1 << 1,
+	FL_IS_PENDING     = 1 << 2,
+	FL_NEED_SORTING   = 1 << 3,
+	FL_NEED_FILTERING = 1 << 4,
+};
+
 #define SPECIAL_IMG_SIZE 48
 #define SPECIAL_IMG_ROWS 4
 #define SPECIAL_IMG_COLS 4
@@ -260,153 +351,187 @@ enum {
 static ImBuf *gSpecialFileImages[SPECIAL_IMG_MAX];
 
 
-static void filelist_from_main(struct FileList *filelist);
-static void filelist_from_library(struct FileList *filelist);
+static void filelist_readjob_main(struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
+static void filelist_readjob_lib(struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
+static void filelist_readjob_dir(struct FileList *, const char *, short *, short *, float *, ThreadMutex *);
 
-static void filelist_read_main(struct FileList *filelist);
-static void filelist_read_library(struct FileList *filelist);
-static void filelist_read_dir(struct FileList *filelist);
+/* helper, could probably go in BKE actually? */
+static int groupname_to_code(const char *group);
+static unsigned int groupname_to_filter_id(const char *group);
 
 static void filelist_filter_clear(FileList *filelist);
+static void filelist_cache_clear(FileListEntryCache *cache, size_t new_size);
 
 /* ********** Sort helpers ********** */
 
-static bool compare_is_directory(const struct direntry *entry)
-{
-	/* for library browse .blend files may be treated as directories, but
-	 * for sorting purposes they should be considered regular files */
-	if (S_ISDIR(entry->type))
-		return !(entry->flags & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP));
-	
-	return false;
-}
-
-static int compare_direntry_generic(const struct direntry *entry1, const struct direntry *entry2)
+static int compare_direntry_generic(const FileListInternEntry *entry1, const FileListInternEntry *entry2)
 {
 	/* type is equal to stat.st_mode */
 
-	if (compare_is_directory(entry1)) {
-		if (compare_is_directory(entry2) == 0) {
-			return -1;
+	if (entry1->typeflag & FILE_TYPE_DIR) {
+	    if (entry2->typeflag & FILE_TYPE_DIR) {
+			/* If both entries are tagged as dirs, we make a 'sub filter' that shows first the real dirs,
+			 * then libs (.blend files), then categories in libs. */
+			if (entry1->typeflag & FILE_TYPE_BLENDERLIB) {
+				if (!(entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
+					return 1;
+				}
+			}
+			else if (entry2->typeflag & FILE_TYPE_BLENDERLIB) {
+				return -1;
+			}
+			else if (entry1->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
+				if (!(entry2->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
+					return 1;
+				}
+			}
+			else if (entry2->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
+				return -1;
+			}
 		}
-	}
-	else if (compare_is_directory(entry2)) {
-		return 1;
-	}
-
-	if (S_ISREG(entry1->type)) {
-		if (!S_ISREG(entry2->type)) {
+		else {
 			return -1;
 		}
 	}
-	else if (S_ISREG(entry2->type)) {
-		return 1;
+	else if (entry2->typeflag & FILE_TYPE_DIR) {
+	    return 1;
 	}
-	if ((entry1->type & S_IFMT) < (entry2->type & S_IFMT)) return -1;
-	if ((entry1->type & S_IFMT) > (entry2->type & S_IFMT)) return 1;
-	
+
 	/* make sure "." and ".." are always first */
-	if (FILENAME_IS_CURRENT(entry1->relname)) return -1;
-	if (FILENAME_IS_CURRENT(entry2->relname)) return 1;
-	if (FILENAME_IS_PARENT(entry1->relname)) return -1;
-	if (FILENAME_IS_PARENT(entry2->relname)) return 1;
+	if (FILENAME_IS_CURRENT(entry1->relpath)) return -1;
+	if (FILENAME_IS_CURRENT(entry2->relpath)) return 1;
+	if (FILENAME_IS_PARENT(entry1->relpath)) return -1;
+	if (FILENAME_IS_PARENT(entry2->relpath)) return 1;
 	
 	return 0;
 }
 
-static int compare_name(const void *a1, const void *a2)
+static int compare_name(void *UNUSED(user_data), const void *a1, const void *a2)
 {
-	const struct direntry *entry1 = a1, *entry2 = a2;
+	const FileListInternEntry *entry1 = a1;
+	const FileListInternEntry *entry2 = a2;
+	char *name1, *name2;
 	int ret;
 
 	if ((ret = compare_direntry_generic(entry1, entry2))) {
 		return ret;
 	}
 
-	return (BLI_natstrcmp(entry1->relname, entry2->relname));
+	name1 = entry1->name;
+	name2 = entry2->name;
+
+	return BLI_natstrcmp(name1, name2);
 }
 
-static int compare_date(const void *a1, const void *a2)	
+static int compare_date(void *UNUSED(user_data), const void *a1, const void *a2)
 {
-	const struct direntry *entry1 = a1, *entry2 = a2;
+	const FileListInternEntry *entry1 = a1;
+	const FileListInternEntry *entry2 = a2;
+	char *name1, *name2;
+	int64_t time1, time2;
 	int ret;
 
 	if ((ret = compare_direntry_generic(entry1, entry2))) {
 		return ret;
 	}
 	
-	if (entry1->s.st_mtime < entry2->s.st_mtime) return 1;
-	if (entry1->s.st_mtime > entry2->s.st_mtime) return -1;
+	time1 = (int64_t)entry1->st.st_mtime;
+	time2 = (int64_t)entry2->st.st_mtime;
+	if (time1 < time2) return 1;
+	if (time1 > time2) return -1;
+
+	name1 = entry1->name;
+	name2 = entry2->name;
 
-	return BLI_natstrcmp(entry1->relname, entry2->relname);
+	return BLI_natstrcmp(name1, name2);
 }
 
-static int compare_size(const void *a1, const void *a2)	
+static int compare_size(void *UNUSED(user_data), const void *a1, const void *a2)
 {
-	const struct direntry *entry1 = a1, *entry2 = a2;
+	const FileListInternEntry *entry1 = a1;
+	const FileListInternEntry *entry2 = a2;
+	char *name1, *name2;
+	uint64_t size1, size2;
 	int ret;
 
 	if ((ret = compare_direntry_generic(entry1, entry2))) {
 		return ret;
 	}
 	
-	if (entry1->s.st_size < entry2->s.st_size) return 1;
-	if (entry1->s.st_size > entry2->s.st_size) return -1;
+	size1 = entry1->st.st_size;
+	size2 = entry2->st.st_size;
+	if (size1 < size2) return 1;
+	if (size1 > size2) return -1;
 
-	return BLI_natstrcmp(entry1->relname, entry2->relname);
+	name1 = entry1->name;
+	name2 = entry2->name;
+
+	return BLI_natstrcmp(name1, name2);
 }
 
-static int compare_extension(const void *a1, const void *a2)
+static int compare_extension(void *UNUSED(user_data), const void *a1, const void *a2)
 {
-	const struct direntry *entry1 = a1, *entry2 = a2;
-	const char *sufix1, *sufix2;
-	const char *nil = "";
+	const FileListInternEntry *entry1 = a1;
+	const FileListInternEntry *entry2 = a2;
+	char *name1, *name2;
 	int ret;
 
 	if ((ret = compare_direntry_generic(entry1, entry2))) {
 		return ret;
 	}
 
-	if (!(sufix1 = strstr(entry1->relname, ".blend.gz")))
-		sufix1 = strrchr(entry1->relname, '.');
-	if (!(sufix2 = strstr(entry2->relname, ".blend.gz")))
-		sufix2 = strrchr(entry2->relname, '.');
-	if (!sufix1) sufix1 = nil;
-	if (!sufix2) sufix2 = nil;
+	if ((entry1->typeflag & FILE_TYPE_BLENDERLIB) && !(entry2->typeflag & FILE_TYPE_BLENDERLIB)) return -1;
+	if (!(entry1->typeflag & FILE_TYPE_BLENDERLIB) && (entry2->typeflag & FILE_TYPE_BLENDERLIB)) return 1;
+	if ((entry1->typeflag & FILE_TYPE_BLENDERLIB) && (entry2->typeflag & FILE_TYPE_BLENDERLIB)) {
+		if ((entry1->typeflag & FILE_TYPE_DIR) && !(entry2->typeflag & FILE_TYPE_DIR)) return 1;
+		if (!(entry1->typeflag & FILE_TYPE_DIR) && (entry2->typeflag & FILE_TYPE_DIR)) return -1;
+		if (entry1->blentype < entry2->blentype) return -1;
+		if (entry1->blentype > entry2->blentype) return 1;
+	}
+	else {
+		const char *sufix1, *sufix2;
 
-	return BLI_strcasecmp(sufix1, sufix2);
-}
+		if (!(sufix1 = strstr(entry1->relpath, ".blend.gz")))
+			sufix1 = strrchr(entry1->relpath, '.');
+		if (!(sufix2 = strstr(entry2->relpath, ".blend.gz")))
+			sufix2 = strrchr(entry2->relpath, '.');
+		if (!sufix1) sufix1 = "";
+		if (!sufix2) sufix2 = "";
 
-bool filelist_need_sorting(struct FileList *filelist)
-{
-	return filelist->need_sorting && (filelist->sort != FILE_SORT_NONE);
+		if ((ret = BLI_strcasecmp(sufix1, sufix2))) {
+			return ret;
+		}
+	}
+
+	name1 = entry1->name;
+	name2 = entry2->name;
+
+	return BLI_natstrcmp(name1, name2);
 }
 
 void filelist_sort(struct FileList *filelist)
 {
-	if (filelist_need_sorting(filelist)) {
-		filelist->need_sorting = false;
-
+	if ((filelist->flags & FL_NEED_SORTING) && (filelist->sort != FILE_SORT_NONE)) {
 		switch (filelist->sort) {
 			case FILE_SORT_ALPHA:
-				qsort(filelist->filelist, filelist->numfiles, sizeof(struct direntry), compare_name);
+				BLI_listbase_sort_r(&filelist->filelist_intern.entries, compare_name, NULL);
 				break;
 			case FILE_SORT_TIME:
-				qsort(filelist->filelist, filelist->numfiles, sizeof(struct direntry), compare_date);
+				BLI_listbase_sort_r(&filelist->filelist_intern.entries, compare_date, NULL);
 				break;
 			case FILE_SORT_SIZE:
-				qsort(filelist->filelist, filelist->numfiles, sizeof(struct direntry), compare_size);
+				BLI_listbase_sort_r(&filelist->filelist_intern.entries, compare_size, NULL);
 				break;
 			case FILE_SORT_EXTENSION:
-				qsort(filelist->filelist, filelist->numfiles, sizeof(struct direntry), compare_extension);
+				BLI_listbase_sort_r(&filelist->filelist_intern.entries, compare_extension, NULL);
 				break;
 			case FILE_SORT_NONE:  /* Should never reach this point! */
 			default:
 				BLI_assert(0);
-				return;
 		}
 
 		filelist_filter_clear(filelist);
+		filelist->flags &= ~FL_NEED_SORTING;
 	}
 }
 
@@ -414,7 +539,7 @@ void filelist_setsorting(struct FileList *filelist, const short sort)
 {
 	if (filelist->sort != sort) {
 		filelist->sort = sort;
-		filelist->need_sorting = true;
+		filelist->flags |= FL_NEED_SORTING;
 	}
 }
 
@@ -422,9 +547,10 @@ void filelist_setsorting(struct FileList *filelist, const short sort)
 
 static bool is_hidden_file(const char *filename, FileListFilter *filter)
 {
+	char *sep = (char *)BLI_last_slash(filename);
 	bool is_hidden = false;
 
-	if (filter->hide_dot) {
+	if (filter->flags & FLF_HIDE_DOT) {
 		if (filename[0] == '.' && filename[1] != '.' && filename[1] != '\0') {
 			is_hidden = true; /* ignore .file */
 		}
@@ -435,7 +561,7 @@ static bool is_hidden_file(const char *filename, FileListFilter *filter)
 			}
 		}
 	}
-	if (!is_hidden && filter->hide_parent) {
+	if (!is_hidden && (filter->flags & FLF_HIDE_PARENT)) {
 		if (filename[0] == '.' && filename[1] == '.' && filename[2] == '\0') {
 			is_hidden = true; /* ignore .. */
 		}
@@ -443,22 +569,49 @@ static bool is_hidden_file(const char *filename, FileListFilter *filter)
 	if (!is_hidden && ((filename[0] == '.') && (filename[1] == '\0'))) {
 		is_hidden = true; /* ignore . */
 	}
+	/* filename might actually be a piece of path, in which case we have to check all its parts. */
+	if (!is_hidden && sep) {
+		char tmp_filename[FILE_MAX_LIBEXTRA];
+
+		BLI_strncpy(tmp_filename, filename, sizeof(tmp_filename));
+		sep = tmp_filename + (sep - filename);
+		while (sep) {
+			BLI_assert(sep[1] != '\0');
+			if (is_hidden_file(sep + 1, filter)) {
+				is_hidden = true;
+				break;
+			}
+			*sep = '\0';
+			sep = (char *)BLI_last_slash(tmp_filename);
+		}
+	}
 	return is_hidden;
 }
 
-static bool is_filtered_file(struct direntry *file, const char *UNUSED(root), FileListFilter *filter)
+static bool is_filtered_file(FileListInternEntry *file, const char *UNUSED(root), FileListFilter *filter)
 {
-	bool is_filtered = !is_hidden_file(file->relname, filter);
+	bool is_filtered = !is_hidden_file(file->relpath, filter);
 
-	if (is_filtered && filter->filter && !FILENAME_IS_CURRPAR(file->relname)) {
-		if ((file->type & S_IFDIR) && !(filter->filter & FILE_TYPE_FOLDER)) {
-			is_filtered = false;
+	if (is_filtered && filter->filter && !FILENAME_IS_CURRPAR(file->relpath)) {
+		if (file->typeflag & FILE_TYPE_DIR) {
+			if (file->typeflag & (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
+				if (!(filter->filter & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
+					is_filtered = false;
+				}
+			}
+			else {
+				if (!(filter->filter & FILE_TYPE_FOLDER)) {
+					is_filtered = false;
+				}
+			}
 		}
-		if (!(file->type & S_IFDIR) && !(file->flags & filter->filter)) {
-			is_filtered = false;
+		else {
+			if (!(file->typeflag & filter->filter)) {
+				is_filtered = false;
+			}
 		}
 		if (is_filtered && (filter->filter_search[0] != '\0')) {
-			if (fnmatch(filter->filter_search, file->relname, FNM_CASEFOLD) != 0) {
+			if (fnmatch(filter->filter_search, file->relpath, FNM_CASEFOLD) != 0) {
 				is_filtered = false;
 			}
 		}
@@ -467,16 +620,41 @@ static bool is_filtered_file(struct direntry *file, const char *UNUSED(root), Fi
 	return is_filtered;
 }
 
-static bool is_filtered_lib(struct direntry *file, const char *root, FileListFilter *filter)
+static bool is_filtered_lib(FileListInternEntry *file, const char *root, FileListFilter *filter)
 {
-	bool is_filtered = !is_hidden_file(file->relname, filter);
-	char dir[FILE_MAXDIR];
+	bool is_filtered;
+	char path[FILE_MAX_LIBEXTRA], dir[FILE_MAXDIR], *group, *name;
 
-	if (BLO_library_path_explode(root, dir, NULL, NULL)) {
-		is_filtered = !is_hidden_file(file->relname, filter);
-		if (is_filtered && filter->filter && !FILENAME_IS_CURRPAR(file->relname)) {
+	BLI_join_dirfile(path, sizeof(path), root, file->relpath);
+
+	if (BLO_library_path_explode(path, dir, &group, &name)) {
+		is_filtered = !is_hidden_file(file->relpath, filter);
+		if (is_filtered && filter->filter && !FILENAME_IS_CURRPAR(file->relpath)) {
+			if (file->typeflag & FILE_TYPE_DIR) {
+				if (file->typeflag & (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
+					if (!(filter->filter & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))) {
+						is_filtered = false;
+					}
+				}
+				else {
+					if (!(filter->filter & FILE_TYPE_FOLDER)) {
+						is_filtered = false;
+					}
+				}
+			}
+			if (is_filtered && group) {
+				if (!name && (filter->flags & FLF_HIDE_LIB_DIR)) {
+					is_filtered = false;
+				}
+				else {
+					unsigned int filter_id = groupname_to_filter_id(group);
+					if (!(filter_id & filter->filter_id)) {
+						is_filtered = false;
+					}
+				}
+			}
 			if (is_filtered && (filter->filter_search[0] != '\0')) {
-				if (fnmatch(filter->filter_search, file->relname, FNM_CASEFOLD) != 0) {
+				if (fnmatch(filter->filter_search, file->relpath, FNM_CASEFOLD) != 0) {
 					is_filtered = false;
 				}
 			}
@@ -489,70 +667,97 @@ static bool is_filtered_lib(struct direntry *file, const char *root, FileListFil
 	return is_filtered;
 }
 
-static bool is_filtered_main(struct direntry *file, const char *UNUSED(dir), FileListFilter *filter)
+static bool is_filtered_main(FileListInternEntry *file, const char *UNUSED(dir), FileListFilter *filter)
 {
-	return !is_hidden_file(file->relname, filter);
+	return !is_hidden_file(file->relpath, filter);
 }
 
 static void filelist_filter_clear(FileList *filelist)
 {
-	MEM_SAFE_FREE(filelist->fidx);
-	filelist->numfiltered = 0;
+	filelist->flags |= FL_NEED_FILTERING;
 }
 
 void filelist_filter(FileList *filelist)
 {
 	int num_filtered = 0;
-	int *fidx_tmp;
-	int i;
+	const int num_files = filelist->filelist.nbr_entries;
+	FileListInternEntry **filtered_tmp, *file;
 
-	if (!filelist->filelist) {
+	if (filelist->filelist.nbr_entries == 0) {
 		return;
 	}
 
-	if (filelist->fidx) {
+	if (!(filelist->flags & FL_NEED_FILTERING)) {
 		/* Assume it has already been filtered, nothing else to do! */
 		return;
 	}
 
-	fidx_tmp = MEM_mallocN(sizeof(*fidx_tmp) * (size_t)filelist->numfiles, __func__);
+	filelist->filter_data.flags &= ~FLF_HIDE_LIB_DIR;
+	if (filelist->max_recursion) {
+		/* Never show lib ID 'categories' directories when we are in 'flat' mode, unless
+		 * root path is a blend file. */
+		char dir[FILE_MAXDIR];
+		if (!filelist_islibrary(filelist, dir, NULL)) {
+			filelist->filter_data.flags |= FLF_HIDE_LIB_DIR;
+		}
+	}
 
-	/* Filter remap & count how many files are left after filter in a single loop. */
-	for (i = 0; i < filelist->numfiles; ++i) {
-		struct direntry *file = &filelist->filelist[i];
+	filtered_tmp = MEM_mallocN(sizeof(*filtered_tmp) * (size_t)num_files, __func__);
 
-		if (filelist->filterf(file, filelist->dir, &filelist->filter_data)) {
-			fidx_tmp[num_filtered++] = i;
+	/* Filter remap & count how many files are left after filter in a single loop. */
+	for (file = filelist->filelist_intern.entries.first; file; file = file->next) {
+		if (filelist->filterf(file, filelist->filelist.root, &filelist->filter_data)) {
+			filtered_tmp[num_filtered++] = file;
 		}
 	}
 
-	/* Note: maybe we could even accept filelist->fidx to be filelist->numfiles -len allocated? */
-	filelist->fidx = MEM_mallocN(sizeof(*filelist->fidx) * (size_t)num_filtered, __func__);
-	memcpy(filelist->fidx, fidx_tmp, sizeof(*filelist->fidx) * (size_t)num_filtered);
-	filelist->numfiltered = num_filtered;
+	if (filelist->filelist_intern.filtered) {
+		MEM_freeN(filelist->filelist_intern.filtered);
+	}
+	filelist->filelist_intern.filtered = MEM_mallocN(sizeof(*filelist->filelist_intern.filtered) * (size_t)num_filtered,
+	                                                 __func__);
+	memcpy(filelist->filelist_intern.filtered, filtered_tmp,
+	       sizeof(*filelist->filelist_intern.filtered) * (size_t)num_filtered);
+	filelist->filelist.nbr_entries_filtered = num_filtered;
+//	printf("Filetered: %d over %d entries\n", num_filtered, filelist->filelist.nbr_entries);
+
+	filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
+	filelist->flags &= ~FL_NEED_FILTERING;
 
-	MEM_freeN(fidx_tmp);
+	MEM_freeN(filtered_tmp);
 }
 
 void filelist_setfilter_options(FileList *filelist, const bool hide_dot, const bool hide_parent,
-                                const unsigned int filter,
+                                const unsigned int filter, const unsigned int filter_id,
                                 const char *filter_glob, const char *filter_search)
 {
-	if ((filelist->filter_data.hide_dot != hide_dot) ||
-	    (filelist->filter_data.hide_parent != hide_parent) ||
-	    (filelist->filter_data.filter != filter) ||
-	    !STREQ(filelist->filter_data.filter_glob, filter_glob) ||
-	    (BLI_strcmp_ignore_pad(filelist->filter_data.filter_search, filter_search, '*') != 0))
-	{
-		filelist->filter_data.hide_dot = hide_dot;
-		filelist->filter_data.hide_parent = hide_parent;
+	bool update = false;
 
+	if (((filelist->filter_data.flags & FLF_HIDE_DOT) != 0) != (hide_dot != 0)) {
+		filelist->filter_data.flags ^= FLF_HIDE_DOT;
+		update = true;
+	}
+	if (((filelist->filter_data.flags & FLF_HIDE_PARENT) != 0) != (hide_parent != 0)) {
+		filelist->filter_data.flags ^= FLF_HIDE_PARENT;
+		update = true;
+	}
+	if ((filelist->filter_data.filter != filter) || (filelist->filter_data.filter_id != filter_id)) {
 		filelist->filter_data.filter = filter;
+		filelist->filter_data.filter_id = filter_id;
+		update = true;
+	}
+	if (!STREQ(filelist->filter_data.filter_glob, filter_glob)) {
 		BLI_strncpy(filelist->filter_data.filter_glob, filter_glob, sizeof(filelist->filter_data.filter_glob));
+		update = true;
+	}
+	if ((BLI_strcmp_ignore_pad(filelist->filter_data.filter_search, filter_search, '*') != 0)) {
 		BLI_strncpy_ensure_pad(filelist->filter_data.filter_search, filter_search, '*',
 		                       sizeof(filelist->filter_data.filter_search));
+		update = true;
+	}
 
-		/* And now, free filtered data so that we now we have to filter again. */
+	if (update) {
+		/* And now, free filtered data so that we know we have to filter again. */
 		filelist_filter_clear(filelist);
 	}
 }
@@ -607,101 +812,489 @@ void filelist_imgsize(struct FileList *filelist, short w, short h)
 	filelist->prv_h = h;
 }
 
-ImBuf *filelist_getimage(struct FileList *filelist, const int index)
+static FileDirEntry *filelist_geticon_get_file(struct FileList *filelist, const int index)
 {
-	ImBuf *ibuf = NULL;
-	int fidx = 0;
-
 	BLI_assert(G.background == false);
 
-	if ((index < 0) || (index >= filelist->numfiltered)) {
-		return NULL;
-	}
-	fidx = filelist->fidx[index];
-	ibuf = filelist->filelist[fidx].image;
+	return filelist_file(filelist, index);
+}
 
-	return ibuf;
+ImBuf *filelist_getimage(struct FileList *filelist, const int index)
+{
+	FileDirEntry *file = filelist_geticon_get_file(filelist, index);
+
+	return file->image;
 }
 
-ImBuf *filelist_geticon(struct FileList *filelist, const int index)
+static ImBuf *filelist_geticon_image_ex(const unsigned int typeflag, const char *relpath)
 {
 	ImBuf *ibuf = NULL;
-	struct direntry *file = NULL;
-	int fidx = 0;
-
-	BLI_assert(G.background == false);
 
-	if ((index < 0) || (index >= filelist->numfiltered)) {
-		return NULL;
-	}
-	fidx = filelist->fidx[index];
-	file = &filelist->filelist[fidx];
-	if (file->type & S_IFDIR) {
-		if (FILENAME_IS_PARENT(filelist->filelist[fidx].relname)) {
+	if (typeflag & FILE_TYPE_DIR) {
+		if (FILENAME_IS_PARENT(relpath)) {
 			ibuf = gSpecialFileImages[SPECIAL_IMG_PARENT];
 		}
-		else if (FILENAME_IS_CURRENT(filelist->filelist[fidx].relname)) {
+		else if (FILENAME_IS_CURRENT(relpath)) {
 			ibuf = gSpecialFileImages[SPECIAL_IMG_REFRESH];
 		}
 		else {
 			ibuf = gSpecialFileImages[SPECIAL_IMG_FOLDER];
 		}
 	}
-	else {
-		ibuf = gSpecialFileImages[SPECIAL_IMG_UNKNOWNFILE];
-	}
-
-	if (file->flags & FILE_TYPE_BLENDER) {
+	else if (typeflag & FILE_TYPE_BLENDER) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_BLENDFILE];
 	}
-	else if (file->flags & FILE_TYPE_MOVIE) {
+	else if (typeflag & FILE_TYPE_BLENDERLIB) {
+		ibuf = gSpecialFileImages[SPECIAL_IMG_UNKNOWNFILE];
+	}
+	else if (typeflag & (FILE_TYPE_MOVIE)) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_MOVIEFILE];
 	}
-	else if (file->flags & FILE_TYPE_SOUND) {
+	else if (typeflag & FILE_TYPE_SOUND) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_SOUNDFILE];
 	}
-	else if (file->flags & FILE_TYPE_PYSCRIPT) {
+	else if (typeflag & FILE_TYPE_PYSCRIPT) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_PYTHONFILE];
 	}
-	else if (file->flags & FILE_TYPE_FTFONT) {
+	else if (typeflag & FILE_TYPE_FTFONT) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_FONTFILE];
 	}
-	else if (file->flags & FILE_TYPE_TEXT) {
+	else if (typeflag & FILE_TYPE_TEXT) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_TEXTFILE];
 	}
-	else if (file->flags & FILE_TYPE_IMAGE) {
+	else if (typeflag & FILE_TYPE_IMAGE) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_LOADING];
 	}
-	else if (file->flags & FILE_TYPE_BLENDER_BACKUP) {
+	else if (typeflag & FILE_TYPE_BLENDER_BACKUP) {
 		ibuf = gSpecialFileImages[SPECIAL_IMG_BACKUP];
 	}
+	else {
+		ibuf = gSpecialFileImages[SPECIAL_IMG_UNKNOWNFILE];
+	}
 
 	return ibuf;
 }
 
+ImBuf *filelist_geticon_image(struct FileList *filelist, const int index)
+{
+	FileDirEntry *file = filelist_geticon_get_file(filelist, index);
+
+	return filelist_geticon_image_ex(file->typeflag, file->relpath);
+}
+
+static int filelist_geticon_ex(
+        const int typeflag, const int blentype, const char *relpath, const bool is_main, const bool ignore_libdir)
+{
+	if ((typeflag & FILE_TYPE_DIR) && !(ignore_libdir && (typeflag & (FILE_TYPE_BLENDERLIB | FILE_TYPE_BLENDER)))) {
+		if (FILENAME_IS_PARENT(relpath)) {
+			return is_main ? ICON_FILE_PARENT : ICON_NONE;
+		}
+		else if (typeflag & FILE_TYPE_APPLICATIONBUNDLE) {
+			return ICON_UGLYPACKAGE;
+		}
+		else if (typeflag & FILE_TYPE_BLENDER) {
+			return ICON_FILE_BLEND;
+		}
+		else if (is_main) {
+			/* Do not return icon for folders if icons are not 'main' draw type (e.g. when used over previews). */
+			return ICON_FILE_FOLDER;
+		}
+	}
+
+	if (typeflag & FILE_TYPE_BLENDER)
+		return ICON_FILE_BLEND;
+	else if (typeflag & FILE_TYPE_BLENDER_BACKUP)
+		return ICON_FILE_BACKUP;
+	else if (typeflag & FILE_TYPE_IMAGE)
+		return ICON_FILE_IMAGE;
+	else if (typeflag & FILE_TYPE_MOVIE)
+		return ICON_FILE_MOVIE;
+	else if (typeflag & FILE_TYPE_PYSCRIPT)
+		return ICON_FILE_SCRIPT;
+	else if (typeflag & FILE_TYPE_SOUND)
+		return ICON_FILE_SOUND;
+	else if (typeflag & FILE_TYPE_FTFONT)
+		return ICON_FILE_FONT;
+	else if (typeflag & FILE_TYPE_BTX)
+		return ICON_FILE_BLANK;
+	else if (typeflag & FILE_TYPE_COLLADA)
+		return ICON_FILE_BLANK;
+	else if (typeflag & FILE_TYPE_TEXT)
+		return ICON_FILE_TEXT;
+	else if (typeflag & FILE_TYPE_BLENDERLIB) {
+		const int ret = UI_idcode_icon_get(blentype);
+		if (ret != ICON_NONE) {
+			return ret;
+		}
+	}
+	return is_main ? ICON_FILE_BLANK : ICON_NONE;
+}
+
+int filelist_geticon(struct FileList *filelist, const int index, const bool is_main)
+{
+	FileDirEntry *file = filelist_geticon_get_file(filelist, index);
+
+	return filelist_geticon_ex(file->typeflag, file->blentype, file->relpath, is_main, false);
+}
+
 /* ********** Main ********** */
 
+static void filelist_checkdir_dir(struct FileList *UNUSED(filelist), char *r_dir)
+{
+	BLI_make_exist(r_dir);
+}
+
+static void filelist_checkdir_lib(struct FileList *UNUSED(filelist), char *r_dir)
+{
+	char dir[FILE_MAXDIR];
+	if (!BLO_library_path_explode(r_dir, dir, NULL, NULL)) {
+		/* if not a valid library, we need it to be a valid directory! */
+		BLI_make_exist(r_dir);
+	}
+}
+
+static void filelist_checkdir_main(struct FileList *filelist, char *r_dir)
+{
+	/* TODO */
+	filelist_checkdir_lib(filelist, r_dir);
+}
+
+static void filelist_entry_clear(FileDirEntry *entry)
+{
+	if (entry->name) {
+		MEM_freeN(entry->name);
+	}
+	if (entry->description) {
+		MEM_freeN(entry->description);
+	}
+	if (entry->relpath) {
+		MEM_freeN(entry->relpath);
+	}
+	if (entry->image) {
+		IMB_freeImBuf(entry->image);
+	}
+	/* For now, consider FileDirEntryRevision::poin as not owned here, so no need to do anything about it */
+
+	if (!BLI_listbase_is_empty(&entry->variants)) {
+		FileDirEntryVariant *var;
+
+		for (var = entry->variants.first; var; var = var->next) {
+			if (var->name) {
+				MEM_freeN(var->name);
+			}
+			if (var->description) {
+				MEM_freeN(var->description);
+			}
+
+			if (!BLI_listbase_is_empty(&var->revisions)) {
+				FileDirEntryRevision *rev;
+
+				for (rev = var->revisions.first; rev; rev = rev->next) {
+					if (rev->comment) {
+						MEM_freeN(rev->comment);
+					}
+				}
+
+				BLI_freelistN(&var->revisions);
+			}
+		}
+
+		/* TODO: tags! */
+
+		BLI_freelistN(&entry->variants);
+	}
+	else if (entry->entry){
+		MEM_freeN(entry->entry);
+	}
+}
+
+static void filelist_entry_free(FileDirEntry *entry)
+{
+	filelist_entry_clear(entry);
+	MEM_freeN(entry);
+}
+
+static void filelist_direntryarr_free(FileDirEntryArr *array)
+{
+	FileDirEntry *entry, *entry_next;
+
+	for (entry = array->entries.first; entry; entry = entry_next) {
+		entry_next = entry->next;
+		filelist_entry_free(entry);
+	}
+	BLI_listbase_clear(&array->entries);
+	array->nbr_entries = 0;
+	array->nbr_entries_filtered = -1;
+	array->entry_idx_start = -1;
+	array->entry_idx_end = -1;
+}
+
+static void filelist_intern_entry_free(FileListInternEntry *entry)
+{
+	if (entry->relpath) {
+		MEM_freeN(entry->relpath);
+	}
+	if (entry->name) {
+		MEM_freeN(entry->name);
+	}
+	MEM_freeN(entry);
+}
+
+static void filelist_intern_free(FileListIntern *filelist_intern)
+{
+	FileListInternEntry *entry, *entry_next;
+
+	for (entry = filelist_intern->entries.first; entry; entry = entry_next) {
+		entry_next = entry->next;
+		filelist_intern_entry_free(entry);
+	}
+	BLI_listbase_clear(&filelist_intern->entries);
+
+	MEM_SAFE_FREE(filelist_intern->filtered);
+}
+
+static void filelist_cache_previewf(TaskPool *pool, void *taskdata, int UNUSED(threadid))
+{
+	FileListEntryCache *cache = taskdata;
+	FileListEntryPreview *preview;
+
+//	printf("%s: Start (%d)...\n", __func__, threadid);
+
+	/* Note we wait on queue here. */
+	while (!BLI_task_pool_canceled(pool) && (preview = BLI_thread_queue_pop(cache->previews_todo))) {
+		ThumbSource source = 0;
+
+//		printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+		BLI_assert(preview->flags & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
+		                             FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB));
+		if (preview->flags & FILE_TYPE_IMAGE) {
+			source = THB_SOURCE_IMAGE;
+		}
+		else if (preview->flags & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB)) {
+			source = THB_SOURCE_BLEND;
+		}
+		else if (preview->flags & FILE_TYPE_MOVIE) {
+			source = THB_SOURCE_MOVIE;
+		}
+		else if (preview->flags & FILE_TYPE_FTFONT) {
+			source = THB_SOURCE_FONT;
+		}
+
+		IMB_thumb_path_lock(preview->path);
+		preview->img = IMB_thumb_manage(preview->path, THB_LARGE, source);
+		IMB_thumb_path_unlock(preview->path);
+
+		BLI_thread_queue_push(cache->previews_done, preview);
+	}
+
+//	printf("%s: End (%d)...\n", __func__, threadid);
+}
+
+static void filelist_cache_preview_ensure_running(FileListEntryCache *cache)
+{
+	if (!cache->previews_pool) {
+		TaskScheduler *scheduler = BLI_task_scheduler_get();
+		TaskPool *pool;
+		int num_tasks = max_ii(2, BLI_system_thread_count() / 2);
+
+		pool = cache->previews_pool = BLI_task_pool_create(scheduler, NULL);
+		cache->previews_todo = BLI_thread_queue_init();
+		cache->previews_done = BLI_thread_queue_init();
+
+		while (num_tasks--) {
+			BLI_task_pool_push(pool, filelist_cache_previewf, cache, false, TASK_PRIORITY_HIGH);
+		}
+		IMB_thumb_locks_acquire();
+	}
+	cache->previews_timestamp = 0.0;
+}
+
+static void filelist_cache_previews_clear(FileListEntryCache *cache)
+{
+	FileListEntryPreview *preview;
+
+	if (cache->previews_pool) {
+		while ((preview = BLI_thread_queue_pop_timeout(cache->previews_todo, 0))) {
+//			printf("%s: TODO %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+			MEM_freeN(preview);
+			cache->previews_pending--;
+		}
+		while ((preview = BLI_thread_queue_pop_timeout(cache->previews_done, 0))) {
+//			printf("%s: DONE %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+			if (preview->img) {
+				IMB_freeImBuf(preview->img);
+			}
+			MEM_freeN(preview);
+			cache->previews_pending--;
+		}
+	}
+//	printf("%s: remaining pending previews: %d\n", __func__, cache->previews_pending);
+}
+
+static void filelist_cache_previews_free(FileListEntryCache *cache, const bool set_inactive)
+{
+	if (cache->previews_pool) {
+		BLI_thread_queue_nowait(cache->previews_todo);
+		BLI_thread_queue_nowait(cache->previews_done);
+		BLI_task_pool_cancel(cache->previews_pool);
+
+		filelist_cache_previews_clear(cache);
+
+		BLI_thread_queue_free(cache->previews_done);
+		BLI_thread_queue_free(cache->previews_todo);
+		BLI_task_pool_free(cache->previews_pool);
+		cache->previews_pool = NULL;
+		cache->previews_todo = NULL;
+		cache->previews_done = NULL;
+
+		IMB_thumb_locks_release();
+	}
+	if (set_inactive) {
+		cache->flags &= ~FLC_PREVIEWS_ACTIVE;
+	}
+	BLI_assert(cache->previews_pending == 0);
+	cache->previews_timestamp = 0.0;
+}
+
+static void filelist_cache_previews_push(FileList *filelist, FileDirEntry *entry, const int index)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+
+	BLI_assert(cache->flags & FLC_PREVIEWS_ACTIVE);
+
+	if (!entry->image &&
+	    !(entry->flags & FILE_ENTRY_INVALID_PREVIEW) &&
+		(entry->typeflag & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
+	                        FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP | FILE_TYPE_BLENDERLIB)))
+	{
+		FileListEntryPreview *preview = MEM_mallocN(sizeof(*preview), __func__);
+		BLI_join_dirfile(preview->path, sizeof(preview->path), filelist->filelist.root, entry->relpath);
+		preview->index = index;
+		preview->flags = entry->typeflag;
+		preview->img = NULL;
+//		printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+
+		filelist_cache_preview_ensure_running(cache);
+		BLI_thread_queue_push(cache->previews_todo, preview);
+		cache->previews_pending++;
+	}
+}
+
+static void filelist_cache_init(FileListEntryCache *cache, size_t cache_size)
+{
+	cache->block_cursor = cache->block_start_index = cache->block_center_index = cache->block_end_index = 0;
+	cache->block_entries = MEM_mallocN(sizeof(*cache->block_entries) * cache_size, __func__);
+
+	cache->misc_entries = BLI_ghash_ptr_new_ex(__func__, cache_size);
+	cache->misc_entries_indices = MEM_mallocN(sizeof(*cache->misc_entries_indices) * cache_size, __func__);
+	copy_vn_i(cache->misc_entries_indices, cache_size, -1);
+	cache->misc_cursor = 0;
+
+	/* XXX This assumes uint is 32 bits and uuid is 128 bits (char[16]), be careful! */
+	cache->uuids = BLI_ghash_new_ex(
+	                   BLI_ghashutil_uinthash_v4_p, BLI_ghashutil_uinthash_v4_cmp, __func__, cache_size * 2);
+
+	cache->size = cache_size;
+	cache->flags = FLC_IS_INIT;
+}
+
+static void filelist_cache_free(FileListEntryCache *cache)
+{
+	if (!(cache->flags & FLC_IS_INIT)) {
+		return;
+	}
+
+	filelist_cache_previews_free(cache, true);
+
+	/* Note we nearly have nothing to do here, entries are just 'borrowed', not owned by cache... */
+	MEM_freeN(cache->block_entries);
+
+	BLI_ghash_free(cache->misc_entries, NULL, NULL);
+	MEM_freeN(cache->misc_entries_indices);
+
+	BLI_ghash_free(cache->uuids, NULL, NULL);
+}
+
+static void filelist_cache_clear(FileListEntryCache *cache, size_t new_size)
+{
+	if (!(cache->flags & FLC_IS_INIT)) {
+		return;
+	}
+
+	filelist_cache_previews_clear(cache);
+
+	/* Note we nearly have nothing to do here, entries are just 'borrowed', not owned by cache... */
+	cache->block_cursor = cache->block_start_index = cache->block_center_index = cache->block_end_index = 0;
+	if (new_size != cache->size) {
+		cache->block_entries = MEM_reallocN(cache->block_entries, sizeof(*cache->block_entries) * new_size);
+	}
+
+	BLI_ghash_clear_ex(cache->misc_entries, NULL, NULL, new_size);
+	if (new_size != cache->size) {
+		cache->misc_entries_indices = MEM_reallocN(cache->misc_entries_indices,
+												   sizeof(*cache->misc_entries_indices) * new_size);
+	}
+	copy_vn_i(cache->misc_entries_indices, new_size, -1);
+
+	BLI_ghash_clear_ex(cache->uuids, NULL, NULL, new_size * 2);
+
+	cache->size = new_size;
+}
+
 FileList *filelist_new(short type)
 {
 	FileList *p = MEM_callocN(sizeof(*p), __func__);
 
+	filelist_cache_init(&p->filelist_cache, FILELIST_ENTRYCACHESIZE_DEFAULT);
+
+	p->selection_state = BLI_ghash_new(BLI_ghashutil_uinthash_v4_p, BLI_ghashutil_uinthash_v4_cmp, __func__);
+
 	switch (type) {
 		case FILE_MAIN:
-			p->readf = filelist_read_main;
+			p->checkdirf = filelist_checkdir_main;
+			p->read_jobf = filelist_readjob_main;
 			p->filterf = is_filtered_main;
 			break;
 		case FILE_LOADLIB:
-			p->readf = filelist_read_library;
+			p->checkdirf = filelist_checkdir_lib;
+			p->read_jobf = filelist_readjob_lib;
 			p->filterf = is_filtered_lib;
 			break;
 		default:
-			p->readf = filelist_read_dir;
+			p->checkdirf = filelist_checkdir_dir;
+			p->read_jobf = filelist_readjob_dir;
 			p->filterf = is_filtered_file;
 			break;
 	}
 	return p;
 }
 
+void filelist_clear_ex(struct FileList *filelist, const bool do_cache, const bool do_selection)
+{
+	if (!filelist) {
+		return;
+	}
+
+	filelist_filter_clear(filelist);
+
+	if (do_cache) {
+		filelist_cache_clear(&filelist->filelist_cache, filelist->filelist_cache.size);
+	}
+
+	filelist_intern_free(&filelist->filelist_intern);
+
+	filelist_direntryarr_free(&filelist->filelist);
+
+	if (do_selection && filelist->selection_state) {
+		BLI_ghash_clear(filelist->selection_state, MEM_freeN, NULL);
+	}
+}
+
+void filelist_clear(struct FileList *filelist)
+{
+	filelist_clear_ex(filelist, true, true);
+}
+
 void filelist_free(struct FileList *filelist)
 {
 	if (!filelist) {
@@ -709,16 +1302,18 @@ void filelist_free(struct FileList *filelist)
 		return;
 	}
 	
-	MEM_SAFE_FREE(filelist->fidx);
-	filelist->numfiltered = 0;
+	filelist_clear_ex(filelist, false, false);  /* No need to clear cache & selection_state, we free them anyway. */
+	filelist_cache_free(&filelist->filelist_cache);
+
+	if (filelist->selection_state) {
+		BLI_ghash_free(filelist->selection_state, MEM_freeN, NULL);
+		filelist->selection_state = NULL;
+	}
+
 	memset(&filelist->filter_data, 0, sizeof(filelist->filter_data));
 
-	filelist->need_sorting = false;
+	filelist->flags &= ~(FL_NEED_SORTING | FL_NEED_FILTERING);
 	filelist->sort = FILE_SORT_NONE;
-
-	BLI_filelist_free(filelist->filelist, filelist->numfiles, NULL);
-	filelist->numfiles = 0;
-	filelist->filelist = NULL;
 }
 
 void filelist_freelib(struct FileList *filelist)
@@ -733,49 +1328,194 @@ BlendHandle *filelist_lib(struct FileList *filelist)
 	return filelist->libfiledata;
 }
 
-int filelist_numfiles(struct FileList *filelist)
+static const char *fileentry_uiname(const char *root, const char *relpath, const int typeflag, char *buff)
 {
-	return filelist->numfiltered;
+	char *name = NULL;
+
+	if (typeflag & FILE_TYPE_BLENDERLIB) {
+		char abspath[FILE_MAX_LIBEXTRA];
+		char *group;
+
+		BLI_join_dirfile(abspath, sizeof(abspath), root, relpath);
+		BLO_library_path_explode(abspath, buff, &group, &name);
+		if (!name) {
+			name = group;
+		}
+	}
+	/* Depending on platforms, 'my_file.blend/..' might be viewed as dir or not... */
+	if (!name) {
+		if (typeflag & FILE_TYPE_DIR) {
+			name = (char *)relpath;
+		}
+		else {
+			name = (char *)BLI_path_basename(relpath);
+		}
+	}
+	BLI_assert(name);
+
+	return name;
 }
 
 const char *filelist_dir(struct FileList *filelist)
 {
-	return filelist->dir;
+	return filelist->filelist.root;
 }
 
-void filelist_setdir(struct FileList *filelist, const char *dir)
+/**
+ * May modify in place given r_dir, which is expected to be FILE_MAX_LIBEXTRA length.
+ */
+void filelist_setdir(struct FileList *filelist, char *r_dir)
 {
-	BLI_strncpy(filelist->dir, dir, sizeof(filelist->dir));
+#ifndef NDEBUG
+	size_t len = strlen(r_dir);
+	BLI_assert((len < FILE_MAX_LIBEXTRA) && ELEM(r_dir[len - 1], SEP, ALTSEP));
+#endif
+
+	BLI_cleanup_dir(G.main->name, r_dir);
+	BLI_add_slash(r_dir);
+	filelist->checkdirf(filelist, r_dir);
+
+	if (!STREQ(filelist->filelist.root, r_dir)) {
+		BLI_strncpy(filelist->filelist.root, r_dir, sizeof(filelist->filelist.root));
+		filelist->flags |= FL_FORCE_RESET;
+	}
 }
 
-short filelist_changed(struct FileList *filelist)
+void filelist_setrecursion(struct FileList *filelist, const int recursion_level)
 {
-	return filelist->changed;
+	if (filelist->max_recursion != recursion_level) {
+		filelist->max_recursion = recursion_level;
+		filelist->flags |= FL_FORCE_RESET;
+	}
 }
 
-struct direntry *filelist_file(struct FileList *filelist, int index)
+bool filelist_force_reset(struct FileList *filelist)
 {
-	int fidx = 0;
-	
-	if ((index < 0) || (index >= filelist->numfiltered)) {
+	return (filelist->flags & FL_FORCE_RESET) != 0;
+}
+
+bool filelist_is_ready(struct FileList *filelist)
+{
+	return (filelist->flags & FL_IS_READY) != 0;
+}
+
+bool filelist_pending(struct FileList *filelist)
+{
+	return (filelist->flags & FL_IS_PENDING) != 0;
+}
+
+/**
+ * Limited version of full update done by space_file's file_refresh(), to be used by operators and such.
+ * Ensures given filelist is ready to be used (i.e. it is filtered and sorted), unless it is tagged for a full refresh.
+ */
+int filelist_files_ensure(FileList *filelist)
+{
+	if (!filelist_force_reset(filelist) || !filelist_empty(filelist)) {
+		filelist_sort(filelist);
+		filelist_filter(filelist);
+	}
+
+	return filelist->filelist.nbr_entries_filtered;;
+}
+
+static FileDirEntry *filelist_file_create_entry(FileList *filelist, const int index)
+{
+	FileListInternEntry *entry = filelist->filelist_intern.filtered[index];
+	FileDirEntry *ret;
+	FileDirEntryRevision *rev;
+
+	ret = MEM_callocN(sizeof(*ret), __func__);
+	rev = MEM_callocN(sizeof(*rev), __func__);
+
+	rev->size = (uint64_t)entry->st.st_size;
+
+	rev->time = (int64_t)entry->st.st_mtime;
+
+	ret->entry = rev;
+	ret->relpath = BLI_strdup(entry->relpath);
+	ret->name = BLI_strdup(entry->name);
+	ret->description = BLI_strdupcat(filelist->filelist.root, entry->relpath);
+	memcpy(ret->uuid, entry->uuid, sizeof(ret->uuid));
+	ret->blentype = entry->blentype;
+	ret->typeflag = entry->typeflag;
+
+	BLI_addtail(&filelist->filelist.entries, ret);
+	return ret;
+}
+
+static void filelist_file_release_entry(FileList *filelist, FileDirEntry *entry)
+{
+	BLI_remlink(&filelist->filelist.entries, entry);
+	filelist_entry_free(entry);
+}
+
+static FileDirEntry *filelist_file_ex(struct FileList *filelist, const int index, const bool use_request)
+{
+	FileDirEntry *ret = NULL, *old;
+	FileListEntryCache *cache = &filelist->filelist_cache;
+	const size_t cache_size = cache->size;
+	int old_index;
+
+	if ((index < 0) || (index >= filelist->filelist.nbr_entries_filtered)) {
+		return ret;
+	}
+
+	if (index >= cache->block_start_index && index < cache->block_end_index) {
+		const int idx = (index - cache->block_start_index + cache->block_cursor) % cache_size;
+		return cache->block_entries[idx];
+	}
+
+	if ((ret = BLI_ghash_lookup(cache->misc_entries, SET_INT_IN_POINTER(index)))) {
+		return ret;
+	}
+
+	if (!use_request) {
 		return NULL;
 	}
-	fidx = filelist->fidx[index];
 
-	return &filelist->filelist[fidx];
+//	printf("requesting file %d (not yet cached)\n", index);
+
+	/* Else, we have to add new entry to 'misc' cache - and possibly make room for it first! */
+	ret = filelist_file_create_entry(filelist, index);
+	old_index = cache->misc_entries_indices[cache->misc_cursor];
+	if ((old = BLI_ghash_popkey(cache->misc_entries, SET_INT_IN_POINTER(old_index), NULL))) {
+		BLI_ghash_remove(cache->uuids, old->uuid, NULL, NULL);
+		filelist_file_release_entry(filelist, old);
+	}
+	BLI_ghash_insert(cache->misc_entries, SET_INT_IN_POINTER(index), ret);
+	BLI_ghash_insert(cache->uuids, ret->uuid, ret);
+
+	cache->misc_entries_indices[cache->misc_cursor] = index;
+	cache->misc_cursor = (cache->misc_cursor + 1) % cache_size;
+
+#if 0  /* Actually no, only block cached entries should have preview imho. */
+	if (cache->previews_pool) {
+		filelist_cache_previews_push(filelist, ret, index);
+	}
+#endif
+
+	return ret;
+}
+
+FileDirEntry *filelist_file(struct FileList *filelist, int index)
+{
+	return filelist_file_ex(filelist, index, true);
 }
 
-int filelist_find(struct FileList *filelist, const char *filename)
+int filelist_file_findpath(struct FileList *filelist, const char *filename)
 {
 	int fidx = -1;
 	
-	if (!filelist->fidx) 
+	if (filelist->filelist.nbr_entries_filtered < 0) {
 		return fidx;
+	}
 
-	for (fidx = 0; fidx < filelist->numfiltered; fidx++) {
-		int index = filelist->fidx[fidx];
+	/* XXX TODO Cache could probably use a ghash on paths too? Not really urgent though.
+     *          This is only used to find again renamed entry, annoying but looks hairy to get rid of it currently. */
 
-		if (STREQ(filelist->filelist[index].relname, filename)) {
+	for (fidx = 0; fidx < filelist->filelist.nbr_entries_filtered; fidx++) {
+		FileListInternEntry *entry = filelist->filelist_intern.filtered[fidx];
+		if (STREQ(entry->relpath, filename)) {
 			return fidx;
 		}
 	}
@@ -783,6 +1523,375 @@ int filelist_find(struct FileList *filelist, const char *filename)
 	return -1;
 }
 
+FileDirEntry *filelist_entry_find_uuid(struct FileList *filelist, const int uuid[4])
+{
+	if (filelist->filelist.nbr_entries_filtered < 0) {
+		return NULL;
+	}
+
+	if (filelist->filelist_cache.uuids) {
+		FileDirEntry *entry = BLI_ghash_lookup(filelist->filelist_cache.uuids, uuid);
+		if (entry) {
+			return entry;
+		}
+	}
+
+	{
+		int fidx;
+
+		for (fidx = 0; fidx < filelist->filelist.nbr_entries_filtered; fidx++) {
+			FileListInternEntry *entry = filelist->filelist_intern.filtered[fidx];
+			if (memcmp(entry->uuid, uuid, sizeof(entry->uuid)) == 0) {
+				return filelist_file(filelist, fidx);
+			}
+		}
+	}
+
+	return NULL;
+}
+
+void filelist_file_cache_slidingwindow_set(FileList *filelist, size_t window_size)
+{
+	/* Always keep it power of 2, in [256, 8192] range for now, cache being app. twice bigger than requested window. */
+	size_t size = 256;
+	window_size *= 2;
+
+	while (size < window_size && size < 8192) {
+		size *= 2;
+	}
+
+	if (size != filelist->filelist_cache.size) {
+		filelist_cache_clear(&filelist->filelist_cache, size);
+	}
+}
+
+/* Helpers, low-level, they assume cursor + size <= cache_size */
+static bool filelist_file_cache_block_create(FileList *filelist, const int start_index, const int size, int cursor)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+
+	{
+		int i, idx;
+
+		for (i = 0, idx = start_index; i < size; i++, idx++, cursor++) {
+			FileDirEntry *entry = filelist_file_create_entry(filelist, idx);
+			cache->block_entries[cursor] = entry;
+			BLI_ghash_insert(cache->uuids, entry->uuid, entry);
+		}
+		return true;
+	}
+
+	return false;
+}
+
+static void filelist_file_cache_block_release(struct FileList *filelist, const int size, int cursor)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+
+	{
+		int i;
+
+		for (i = 0; i < size; i++, cursor++) {
+			FileDirEntry *entry = cache->block_entries[cursor];
+//			printf("%s: release cacheidx %d (%%p %%s)\n", __func__, cursor/*, cache->block_entries[cursor], cache->block_entries[cursor]->relpath*/);
+			BLI_ghash_remove(cache->uuids, entry->uuid, NULL, NULL);
+			filelist_file_release_entry(filelist, entry);
+#ifndef NDEBUG
+			cache->block_entries[cursor] = NULL;
+#endif
+		}
+	}
+}
+
+/* Load in cache all entries "around" given index (as much as block cache may hold). */
+bool filelist_file_cache_block(struct FileList *filelist, const int index)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+	const size_t cache_size = cache->size;
+
+	const int nbr_entries = filelist->filelist.nbr_entries_filtered;
+	int start_index = max_ii(0, index - (cache_size / 2));
+	int end_index = min_ii(nbr_entries, index + (cache_size / 2));
+	int i;
+
+	if ((index < 0) || (index >= nbr_entries)) {
+//		printf("Wrong index %d ([%d:%d])", index, 0, nbr_entries);
+		return false;
+	}
+
+	/* Maximize cached range! */
+	if ((end_index - start_index) < cache_size) {
+		if (start_index == 0) {
+			end_index = min_ii(nbr_entries, start_index + cache_size);
+		}
+		else if (end_index == nbr_entries) {
+			start_index = max_ii(0, end_index - cache_size);
+		}
+	}
+
+	BLI_assert((end_index - start_index) <= cache_size) ;
+
+//	printf("%s: [%d:%d] around index %d (current cache: [%d:%d])\n", __func__,
+//	       start_index, end_index, index, cache->block_start_index, cache->block_end_index);
+
+	/* If we have something to (re)cache... */
+	if ((start_index != cache->block_start_index) || (end_index != cache->block_end_index)) {
+		if ((start_index >= cache->block_end_index) || (end_index <= cache->block_start_index)) {
+			int size1 = cache->block_end_index - cache->block_start_index;
+			int size2 = 0;
+			int idx1 = cache->block_cursor, idx2 = 0;
+
+//			printf("Full Recaching!\n");
+
+			if (cache->flags & FLC_PREVIEWS_ACTIVE) {
+				filelist_cache_previews_clear(cache);
+			}
+
+			if (idx1 + size1 > cache_size) {
+				size2 = idx1 + size1 - cache_size;
+				size1 -= size2;
+				filelist_file_cache_block_release(filelist, size2, idx2);
+			}
+			filelist_file_cache_block_release(filelist, size1, idx1);
+
+			cache->block_start_index = cache->block_end_index = cache->block_cursor = 0;
+
+			/* New cached block does not overlap existing one, simple. */
+			if (!filelist_file_cache_block_create(filelist, start_index, end_index - start_index, 0)) {
+				return false;
+			}
+
+			cache->block_start_index = start_index;
+			cache->block_end_index = end_index;
+		}
+		else {
+//			printf("Partial Recaching!\n");
+
+			/* At this point, we know we keep part of currently cached entries, so update previews if needed,
+			 * and remove everything from working queue - we'll add all newly needed entries at the end. */
+			if (cache->flags & FLC_PREVIEWS_ACTIVE) {
+				filelist_cache_previews_update(filelist);
+				filelist_cache_previews_clear(cache);
+			}
+
+//			printf("\tpreview cleaned up...\n");
+
+			if (start_index > cache->block_start_index) {
+				int size1 = start_index - cache->block_start_index;
+				int size2 = 0;
+				int idx1 = cache->block_cursor, idx2 = 0;
+
+//				printf("\tcache releasing: [%d:%d] (%d, %d)\n", cache->block_start_index, cache->block_start_index + size1, cache->block_cursor, size1);
+
+				if (idx1 + size1 > cache_size) {
+					size2 = idx1 + size1 - cache_size;
+					size1 -= size2;
+					filelist_file_cache_block_release(filelist, size2, idx2);
+				}
+				filelist_file_cache_block_release(filelist, size1, idx1);
+
+				cache->block_cursor = (idx1 + size1 + size2) % cache_size;
+				cache->block_start_index = start_index;
+			}
+			if (end_index < cache->block_end_index) {
+				int size1 = cache->block_end_index - end_index;
+				int size2 = 0;
+				int idx1, idx2 = 0;
+
+//				printf("\tcache releasing: [%d:%d] (%d)\n", cache->block_end_index - size1, cache->block_end_index, cache->block_cursor);
+
+				idx1 = (cache->block_cursor + end_index - cache->block_start_index) % cache_size;
+				if (idx1 + size1 > cache_size) {
+					size2 = idx1 + size1 - cache_size;
+					size1 -= size2;
+					filelist_file_cache_block_release(filelist, size2, idx2);
+				}
+				filelist_file_cache_block_release(filelist, size1, idx1);
+
+				cache->block_end_index = end_index;
+			}
+
+//			printf("\tcache cleaned up...\n");
+
+			if (start_index < cache->block_start_index) {
+				/* Add (request) needed entries before already cached ones. */
+				/* Note: We need some index black magic to wrap around (cycle) inside our cache_size array... */
+				int size1 = cache->block_start_index - start_index;
+				int size2 = 0;
+				int idx1, idx2;
+
+				if (size1 > cache->block_cursor) {
+					size2 = size1;
+					size1 -= cache->block_cursor;
+					size2 -= size1;
+					idx2 = 0;
+					idx1 = cache_size - size1;
+				}
+				else {
+					idx1 = cache->block_cursor - size1;
+				}
+
+				if (size2) {
+					if (!filelist_file_cache_block_create(filelist, start_index + size1, size2, idx2)) {
+						return false;
+					}
+				}
+				if (!filelist_file_cache_block_create(filelist, start_index, size1, idx1)) {
+					return false;
+				}
+
+				cache->block_cursor = idx1;
+				cache->block_start_index = start_index;
+			}
+//			printf("\tstart-extended...\n");
+			if (end_index > cache->block_end_index) {
+				/* Add (request) needed entries after already cached ones. */
+				/* Note: We need some index black magic to wrap around (cycle) inside our cache_size array... */
+				int size1 = end_index - cache->block_end_index;
+				int size2 = 0;
+				int idx1, idx2;
+
+				idx1 = (cache->block_cursor + end_index - cache->block_start_index - size1) % cache_size;
+				if ((idx1 + size1) > cache_size) {
+					size2 = size1;
+					size1 = cache_size - idx1;
+					size2 -= size1;
+					idx2 = 0;
+				}
+
+				if (size2) {
+					if (!filelist_file_cache_block_create(filelist, end_index - size2, size2, idx2)) {
+						return false;
+					}
+				}
+				if (!filelist_file_cache_block_create(filelist, end_index - size1 - size2, size1, idx1)) {
+					return false;
+				}
+
+				cache->block_end_index = end_index;
+			}
+
+//			printf("\tend-extended...\n");
+		}
+	}
+	else if ((cache->block_center_index != index) && (cache->flags & FLC_PREVIEWS_ACTIVE)) {
+		/* We try to always preview visible entries first, so 'restart' preview background task. */
+		filelist_cache_previews_update(filelist);
+		filelist_cache_previews_clear(cache);
+	}
+
+//	printf("Re-queueing previews...\n");
+
+	/* Note we try to preview first images around given index - i.e. assumed visible ones. */
+	if (cache->flags & FLC_PREVIEWS_ACTIVE) {
+		for (i = 0; ((index + i) < end_index) || ((index - i) >= start_index); i++) {
+			if ((index - i) >= start_index) {
+				const int idx = (cache->block_cursor + (index - start_index) - i) % cache_size;
+				filelist_cache_previews_push(filelist, cache->block_entries[idx], index - i);
+			}
+			if ((index + i) < end_index) {
+				const int idx = (cache->block_cursor + (index - start_index) + i) % cache_size;
+				filelist_cache_previews_push(filelist, cache->block_entries[idx], index + i);
+			}
+		}
+	}
+
+	cache->block_center_index = index;
+
+//	printf("%s Finished!\n", __func__);
+
+	return true;
+}
+
+void filelist_cache_previews_set(FileList *filelist, const bool use_previews)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+
+	if (use_previews == ((cache->flags & FLC_PREVIEWS_ACTIVE) != 0)) {
+		return;
+	}
+	/* Do not start preview work while listing, gives nasty flickering! */
+	else if (use_previews && (filelist->flags & FL_IS_READY)) {
+		cache->flags |= FLC_PREVIEWS_ACTIVE;
+
+		BLI_assert((cache->previews_pool == NULL) && (cache->previews_todo == NULL) && (cache->previews_done == NULL));
+
+//		printf("%s: Init Previews...\n", __func__);
+
+		/* No need to populate preview queue here, filelist_file_cache_block() handles this. */
+	}
+	else {
+//		printf("%s: Clear Previews...\n", __func__);
+
+		filelist_cache_previews_free(cache, true);
+	}
+}
+
+bool filelist_cache_previews_update(FileList *filelist)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+	TaskPool *pool = cache->previews_pool;
+	bool changed = false;
+
+	if (!pool) {
+		return changed;
+	}
+
+//	printf("%s: Update Previews...\n", __func__);
+
+	while (!BLI_thread_queue_is_empty(cache->previews_done)) {
+		FileListEntryPreview *preview = BLI_thread_queue_pop(cache->previews_done);
+
+		/* entry might have been removed from cache in the mean while, we do not want to cache it again here. */
+		FileDirEntry *entry = filelist_file_ex(filelist, preview->index, false);
+
+//		printf("%s: %d - %s - %p\n", __func__, preview->index, preview->path, preview->img);
+
+		if (preview->img) {
+			/* Due to asynchronous process, a preview for a given image may be generated several times, i.e.
+			 * entry->image may already be set at this point. */
+			if (entry && !entry->image) {
+				entry->image = preview->img;
+				changed = true;
+			}
+			else {
+				IMB_freeImBuf(preview->img);
+			}
+		}
+		else if (entry) {
+			/* We want to avoid re-processing this entry continuously!
+			 * Note that, since entries only live in cache, preview will be retried quite often anyway. */
+			entry->flags |= FILE_ENTRY_INVALID_PREVIEW;
+		}
+
+		MEM_freeN(preview);
+		cache->previews_pending--;
+		BLI_assert(cache->previews_pending >= 0);
+	}
+
+//	printf("%s: Previews pending: %d\n", __func__, cache->previews_pending);
+	if (cache->previews_pending == 0) {
+		if (cache->previews_timestamp == 0.0) {
+			cache->previews_timestamp = PIL_check_seconds_timer();
+		}
+		else if (PIL_check_seconds_timer() - cache->previews_timestamp > 1.0) {
+			/* Preview task is IDLE since more than (approximatively) 1000ms,
+			 * kill workers & task for now - they will be automatically restarted when needed. */
+//			printf("%s: Inactive preview task, sleeping (%f vs %f)!\n", __func__, PIL_check_seconds_timer(), cache->previews_timestamp);
+			filelist_cache_previews_free(cache, false);
+		}
+	}
+
+	return changed;
+}
+
+bool filelist_cache_previews_running(FileList *filelist)
+{
+	FileListEntryCache *cache = &filelist->filelist_cache;
+
+	return (cache->previews_pool != NULL);
+}
+
 /* would recognize .blend as well */
 static bool file_is_blend_backup(const char *str)
 {
@@ -857,10 +1966,10 @@ static int path_extension_type(const char *path)
 	return 0;
 }
 
-static int file_extension_type(const char *dir, const char *relname)
+static int file_extension_type(const char *dir, const char *relpath)
 {
 	char path[FILE_MAX];
-	BLI_join_dirfile(path, sizeof(path), dir, relname);
+	BLI_join_dirfile(path, sizeof(path), dir, relpath);
 	return path_extension_type(path);
 }
 
@@ -868,185 +1977,137 @@ int ED_file_extension_icon(const char *path)
 {
 	int type = path_extension_type(path);
 	
-	if (type == FILE_TYPE_BLENDER)
-		return ICON_FILE_BLEND;
-	else if (type == FILE_TYPE_BLENDER_BACKUP)
-		return ICON_FILE_BACKUP;
-	else if (type == FILE_TYPE_IMAGE)
-		return ICON_FILE_IMAGE;
-	else if (type == FILE_TYPE_MOVIE)
-		return ICON_FILE_MOVIE;
-	else if (type == FILE_TYPE_PYSCRIPT)
-		return ICON_FILE_SCRIPT;
-	else if (type == FILE_TYPE_SOUND)
-		return ICON_FILE_SOUND;
-	else if (type == FILE_TYPE_FTFONT)
-		return ICON_FILE_FONT;
-	else if (type == FILE_TYPE_BTX)
-		return ICON_FILE_BLANK;
-	else if (type == FILE_TYPE_COLLADA)
-		return ICON_FILE_BLANK;
-	else if (type == FILE_TYPE_TEXT)
-		return ICON_FILE_TEXT;
-	
-	return ICON_FILE_BLANK;
-}
-
-static void filelist_setfiletypes(struct FileList *filelist)
-{
-	struct direntry *file;
-	int num;
-
-	file = filelist->filelist;
-
-	for (num = 0; num < filelist->numfiles; num++, file++) {
-#ifndef __APPLE__
-		/* Don't check extensions for directories, allow in OSX cause bundles have extensions*/
-		if (file->type & S_IFDIR) {
-			continue;
-		}
-#endif
-		if (filelist->filter_data.filter_glob[0] &&
-		    BLI_testextensie_glob(file->relname, filelist->filter_data.filter_glob))
-		{
-			file->flags = FILE_TYPE_OPERATOR;
-		}
-		else {
-			file->flags = file_extension_type(filelist->dir, file->relname);
-		}
+	switch (type) {
+		case FILE_TYPE_BLENDER:
+			return ICON_FILE_BLEND;
+		case FILE_TYPE_BLENDER_BACKUP:
+			return ICON_FILE_BACKUP;
+		case FILE_TYPE_IMAGE:
+			return ICON_FILE_IMAGE;
+		case FILE_TYPE_MOVIE:
+			return ICON_FILE_MOVIE;
+		case FILE_TYPE_PYSCRIPT:
+			return ICON_FILE_SCRIPT;
+		case FILE_TYPE_SOUND:
+			return ICON_FILE_SOUND;
+		case FILE_TYPE_FTFONT:
+			return ICON_FILE_FONT;
+		case FILE_TYPE_BTX:
+			return ICON_FILE_BLANK;
+		case FILE_TYPE_COLLADA:
+			return ICON_FILE_BLANK;
+		case FILE_TYPE_TEXT:
+			return ICON_FILE_TEXT;
+		default:
+			return ICON_FILE_BLANK;
 	}
 }
 
-static void filelist_read_dir(struct FileList *filelist)
-{
-	if (!filelist) return;
-
-	filelist->fidx = NULL;
-	filelist->filelist = NULL;
-
-	BLI_make_exist(filelist->dir);
-	BLI_cleanup_dir(G.main->name, filelist->dir);
-	filelist->numfiles = BLI_filelist_dir_contents(filelist->dir, &(filelist->filelist));
-
-	/* We shall *never* get an empty list here, since we now the dir exists and is readable
-	 * (ensured by BLI_make_exist()). So we expect at the very least the parent '..' entry. */
-	BLI_assert(filelist->numfiles != 0);
-
-	filelist_setfiletypes(filelist);
-}
-
-static void filelist_read_main(struct FileList *filelist)
+int filelist_empty(struct FileList *filelist)
 {
-	if (!filelist) return;
-	filelist_from_main(filelist);
+	return (filelist->filelist.nbr_entries == 0);
 }
 
-static void filelist_read_library(struct FileList *filelist)
+unsigned int filelist_entry_select_set(
+        const FileList *filelist, const FileDirEntry *entry, FileSelType select, unsigned int flag, FileCheckType check)
 {
-	if (!filelist) return;
-	BLI_cleanup_dir(G.main->name, filelist->dir);
-	filelist_from_library(filelist);
-	if (!filelist->libfiledata) {
-		int num;
-		struct direntry *file;
+	/* Default NULL pointer if not found is fine here! */
+	void **es_p = BLI_ghash_lookup_p(filelist->selection_state, entry->uuid);
+	unsigned int entry_flag = es_p ? GET_UINT_FROM_POINTER(*es_p) : 0;
+	const unsigned int org_entry_flag = entry_flag;
 
-		filelist_read_dir(filelist);
-		file = filelist->filelist;
-		for (num = 0; num < filelist->numfiles; num++, file++) {
-			if (BLO_has_bfile_extension(file->relname)) {
-				char name[FILE_MAX];
+	BLI_assert(entry);
+	BLI_assert(ELEM(check, CHECK_DIRS, CHECK_FILES, CHECK_ALL));
 
-				BLI_join_dirfile(name, sizeof(name), filelist->dir, file->relname);
+	if (((check == CHECK_ALL)) ||
+	    ((check == CHECK_DIRS) && (entry->typeflag & FILE_TYPE_DIR)) ||
+	    ((check == CHECK_FILES) && !(entry->typeflag & FILE_TYPE_DIR)))
+	{
+		switch (select) {
+			case FILE_SEL_REMOVE:
+				entry_flag &= ~flag;
+				break;
+			case FILE_SEL_ADD:
+				entry_flag |= flag;
+				break;
+			case FILE_SEL_TOGGLE:
+				entry_flag ^= flag;
+				break;
+		}
+	}
 
-				/* prevent current file being used as acceptable dir */
-				if (BLI_path_cmp(G.main->name, name) != 0) {
-					file->type &= ~S_IFMT;
-					file->type |= S_IFDIR;
-				}
+	if (entry_flag != org_entry_flag) {
+		if (es_p) {
+			if (entry_flag) {
+				*es_p = SET_UINT_IN_POINTER(entry_flag);
+			}
+			else {
+				BLI_ghash_remove(filelist->selection_state, entry->uuid, MEM_freeN, NULL);
 			}
 		}
+		else if (entry_flag) {
+			void *key = MEM_mallocN(sizeof(entry->uuid), __func__);
+			memcpy(key, entry->uuid, sizeof(entry->uuid));
+			BLI_ghash_insert(filelist->selection_state, key, SET_UINT_IN_POINTER(entry_flag));
+		}
 	}
-}
 
-void filelist_readdir(struct FileList *filelist)
-{
-	filelist->readf(filelist);
-
-	filelist->need_sorting = true;
-	filelist->need_thumbnails = true;
-	filelist_filter_clear(filelist);
+	return entry_flag;
 }
 
-int filelist_empty(struct FileList *filelist)
+void filelist_entry_select_index_set(FileList *filelist, const int index, FileSelType select, unsigned int flag, FileCheckType check)
 {
-	return filelist->filelist == NULL;
-}
+	FileDirEntry *entry = filelist_file(filelist, index);
 
-void filelist_select_file(struct FileList *filelist, int index, FileSelType select, unsigned int flag, FileCheckType check)
-{
-	struct direntry *file = filelist_file(filelist, index);
-	if (file != NULL) {
-		int check_ok = 0; 
-		switch (check) {
-			case CHECK_DIRS:
-				check_ok = S_ISDIR(file->type);
-				break;
-			case CHECK_ALL:
-				check_ok = 1;
-				break;
-			case CHECK_FILES:
-			default:
-				check_ok = !S_ISDIR(file->type);
-				break;
-		}
-		if (check_ok) {
-			switch (select) {
-				case FILE_SEL_REMOVE:
-					file->selflag &= ~flag;
-					break;
-				case FILE_SEL_ADD:
-					file->selflag |= flag;
-					break;
-				case FILE_SEL_TOGGLE:
-					file->selflag ^= flag;
-					break;
-			}
-		}
+	if (entry) {
+		filelist_entry_select_set(filelist, entry, select, flag, check);
 	}
 }
 
-void filelist_select(struct FileList *filelist, FileSelection *sel, FileSelType select, unsigned int flag, FileCheckType check)
+void filelist_entries_select_index_range_set(
+        FileList *filelist, FileSelection *sel, FileSelType select, unsigned int flag, FileCheckType check)
 {
 	/* select all valid files between first and last indicated */
-	if ((sel->first >= 0) && (sel->first < filelist->numfiltered) && (sel->last >= 0) && (sel->last < filelist->numfiltered)) {
+	if ((sel->first >= 0) && (sel->first < filelist->filelist.nbr_entries_filtered) &&
+	    (sel->last >= 0) && (sel->last < filelist->filelist.nbr_entries_filtered))
+	{
 		int current_file;
 		for (current_file = sel->first; current_file <= sel->last; current_file++) {
-			filelist_select_file(filelist, current_file, select, flag, check);
+			filelist_entry_select_index_set(filelist, current_file, select, flag, check);
 		}
 	}
 }
 
-bool filelist_is_selected(struct FileList *filelist, int index, FileCheckType check)
+unsigned int filelist_entry_select_get(FileList *filelist, FileDirEntry *entry, FileCheckType check)
 {
-	struct direntry *file = filelist_file(filelist, index);
-	if (!file) {
-		return 0;
-	}
-	switch (check) {
-		case CHECK_DIRS:
-			return S_ISDIR(file->type) && (file->selflag & FILE_SEL_SELECTED);
-		case CHECK_FILES:
-			return S_ISREG(file->type) && (file->selflag & FILE_SEL_SELECTED);
-		case CHECK_ALL:
-		default:
-			return (file->selflag & FILE_SEL_SELECTED) != 0;
+	BLI_assert(entry);
+	BLI_assert(ELEM(check, CHECK_DIRS, CHECK_FILES, CHECK_ALL));
+
+	if (((check == CHECK_ALL)) ||
+	    ((check == CHECK_DIRS) && (entry->typeflag & FILE_TYPE_DIR)) ||
+	    ((check == CHECK_FILES) && !(entry->typeflag & FILE_TYPE_DIR)))
+	{
+		/* Default NULL pointer if not found is fine here! */
+		return GET_UINT_FROM_POINTER(BLI_ghash_lookup(filelist->selection_state, entry->uuid));
 	}
+
+	return 0;
 }
 
+unsigned int filelist_entry_select_index_get(FileList *filelist, const int index, FileCheckType check)
+{
+	FileDirEntry *entry = filelist_file(filelist, index);
+
+	if (entry) {
+		return filelist_entry_select_get(filelist, entry, check);
+	}
+
+	return 0;
+}
 
 bool filelist_islibrary(struct FileList *filelist, char *dir, char **group)
 {
-	return BLO_library_path_explode(filelist->dir, dir, group, NULL);
+	return BLO_library_path_explode(filelist->filelist.root, dir, group, NULL);
 }
 
 static int groupname_to_code(const char *group)
@@ -1054,6 +2115,8 @@ static int groupname_to_code(const char *group)
 	char buf[BLO_GROUP_MAX];
 	char *lslash;
 
+	BLI_assert(group);
+
 	BLI_strncpy(buf, group, sizeof(buf));
 	lslash = (char *)BLI_last_slash(buf);
 	if (lslash)
@@ -1062,182 +2125,231 @@ static int groupname_to_code(const char *group)
 	return buf[0] ? BKE_idcode_from_name(buf) : 0;
 }
 
-static void filelist_from_library(struct FileList *filelist)
+static unsigned int groupname_to_filter_id(const char *group)
+{
+	int id_code = groupname_to_code(group);
+
+	return BKE_idcode_to_idfilter(id_code);
+}
+
+/*
+ * From here, we are in 'Job Context', i.e. have to be careful about sharing stuff between bacground working thread
+ * and main one (used by UI among other things).
+ */
+
+typedef struct TodoDir {
+	int level;
+	char *dir;
+} TodoDir;
+
+static int filelist_readjob_list_dir(
+        const char *root, ListBase *entries, const char *filter_glob,
+        const bool do_lib, const char *main_name, const bool skip_currpar)
+{
+	struct direntry *files;
+	int nbr_files, nbr_entries = 0;
+
+	nbr_files = BLI_filelist_dir_contents(root, &files);
+	if (files) {
+		int i = nbr_files;
+		while (i--) {
+			FileListInternEntry *entry;
+
+			if (skip_currpar && FILENAME_IS_CURRPAR(files[i].relname)) {
+				continue;
+			}
+
+			entry = MEM_callocN(sizeof(*entry), __func__);
+			entry->relpath = MEM_dupallocN(files[i].relname);
+			if (S_ISDIR(files[i].s.st_mode)) {
+				entry->typeflag |= FILE_TYPE_DIR;
+			}
+			entry->st = files[i].s;
+
+			/* Set file type. */
+			/* If we are considering .blend files as libs, promote them to directory status! */
+			if (do_lib && BLO_has_bfile_extension(entry->relpath)) {
+				char name[FILE_MAX];
+
+				entry->typeflag = FILE_TYPE_BLENDER;
+
+				BLI_join_dirfile(name, sizeof(name), root, entry->relpath);
+
+				/* prevent current file being used as acceptable dir */
+				if (BLI_path_cmp(main_name, name) != 0) {
+					entry->typeflag |= FILE_TYPE_DIR;
+				}
+			}
+			/* Otherwise, do not check extensions for directories! */
+			else if (!(entry->typeflag & FILE_TYPE_DIR)) {
+				if (filter_glob[0] && BLI_testextensie_glob(entry->relpath, filter_glob)) {
+					entry->typeflag = FILE_TYPE_OPERATOR;
+				}
+				else {
+					entry->typeflag = file_extension_type(root, entry->relpath);
+				}
+			}
+
+			BLI_addtail(entries, entry);
+			nbr_entries++;
+		}
+		BLI_filelist_free(files, nbr_files);
+	}
+	return nbr_entries;
+}
+
+static int filelist_readjob_list_lib(const char *root, ListBase *entries, const bool skip_currpar)
 {
-	LinkNode *l, *names, *previews;
-	struct ImBuf *ima;
-	int ok, i, nprevs, nnames, idcode;
-	char filename[FILE_MAX];
+	FileListInternEntry *entry;
+	LinkNode *ln, *names;
+	int i, nnames, idcode = 0, nbr_entries = 0;
 	char dir[FILE_MAX], *group;
+	bool ok;
+
+	struct BlendHandle *libfiledata = NULL;
 
 	/* name test */
-	ok = filelist_islibrary(filelist, dir, &group);
+	ok = BLO_library_path_explode(root, dir, &group, NULL);
 	if (!ok) {
-		/* free */
-		if (filelist->libfiledata) BLO_blendhandle_close(filelist->libfiledata);
-		filelist->libfiledata = NULL;
-		return;
+		return nbr_entries;
 	}
-	
-	BLI_strncpy(filename, G.main->name, sizeof(filename));
 
 	/* there we go */
-	/* for the time being only read filedata when libfiledata==0 */
-	if (filelist->libfiledata == NULL) {
-		filelist->libfiledata = BLO_blendhandle_from_file(dir, NULL);
-		if (filelist->libfiledata == NULL) return;
+	libfiledata = BLO_blendhandle_from_file(dir, NULL);
+	if (libfiledata == NULL) {
+		return nbr_entries;
 	}
-	
-	idcode = group ? groupname_to_code(group) : 0;
-
-	/* memory for strings is passed into filelist[i].relname
-	 * and freed in freefilelist */
-	if (idcode) {
-		previews = BLO_blendhandle_get_previews(filelist->libfiledata, idcode, &nprevs);
-		names = BLO_blendhandle_get_datablock_names(filelist->libfiledata, idcode, &nnames);
-		/* ugh, no rewind, need to reopen */
-		BLO_blendhandle_close(filelist->libfiledata);
-		filelist->libfiledata = BLO_blendhandle_from_file(dir, NULL);
-		
+
+	/* memory for strings is passed into filelist[i].entry->relpath and freed in filelist_entry_free. */
+	if (group) {
+		idcode = groupname_to_code(group);
+		names = BLO_blendhandle_get_datablock_names(libfiledata, idcode, &nnames);
 	}
 	else {
-		previews = NULL;
-		nprevs = 0;
-		names = BLO_blendhandle_get_linkable_groups(filelist->libfiledata);
+		names = BLO_blendhandle_get_linkable_groups(libfiledata);
 		nnames = BLI_linklist_count(names);
 	}
 
-	filelist->numfiles = nnames + 1;
-	filelist->filelist = MEM_mallocN(filelist->numfiles * sizeof(*filelist->filelist), __func__);
-	memset(filelist->filelist, 0, filelist->numfiles * sizeof(*filelist->filelist));
-
-	filelist->filelist[0].relname = BLI_strdup(FILENAME_PARENT);
-	filelist->filelist[0].type |= S_IFDIR;
-		
-	for (i = 0, l = names; i < nnames; i++, l = l->next) {
-		const char *blockname = l->link;
+	BLO_blendhandle_close(libfiledata);
 
-		filelist->filelist[i + 1].relname = BLI_strdup(blockname);
-		if (idcode) {
-			filelist->filelist[i + 1].type |= S_IFREG;
-		}
-		else {
-			filelist->filelist[i + 1].type |= S_IFDIR;
-		}
-	}
-
-	if (previews && (nnames != nprevs)) {
-		printf("filelist_from_library: error, found %d items, %d previews\n", nnames, nprevs);
+	if (!skip_currpar) {
+		entry = MEM_callocN(sizeof(*entry), __func__);
+		entry->relpath = BLI_strdup(FILENAME_PARENT);
+		entry->typeflag |= (FILE_TYPE_BLENDERLIB | FILE_TYPE_DIR);
+		BLI_addtail(entries, entry);
+		nbr_entries++;
 	}
-	else if (previews) {
-		for (i = 0, l = previews; i < nnames; i++, l = l->next) {
-			PreviewImage *img = l->link;
 
-			if (img) {
-				unsigned int w = img->w[ICON_SIZE_PREVIEW];
-				unsigned int h = img->h[ICON_SIZE_PREVIEW];
-				unsigned int *rect = img->rect[ICON_SIZE_PREVIEW];
+	for (i = 0, ln = names; i < nnames; i++, ln = ln->next) {
+		const char *blockname = ln->link;
 
-				/* first allocate imbuf for copying preview into it */
-				if (w > 0 && h > 0 && rect) {
-					ima = IMB_allocImBuf(w, h, 32, IB_rect);
-					memcpy(ima->rect, rect, w * h * sizeof(unsigned int));
-					filelist->filelist[i + 1].image = ima;
-					filelist->filelist[i + 1].flags = FILE_TYPE_IMAGE;
-				}
-			}
+		entry = MEM_callocN(sizeof(*entry), __func__);
+		entry->relpath = BLI_strdup(blockname);
+		entry->typeflag |= FILE_TYPE_BLENDERLIB;
+		if (!(group && idcode)) {
+			entry->typeflag |= FILE_TYPE_DIR;
+			entry->blentype = groupname_to_code(blockname);
 		}
+		else {
+			entry->blentype = idcode;
+		}
+		BLI_addtail(entries, entry);
+		nbr_entries++;
 	}
 
 	BLI_linklist_free(names, free);
-	if (previews) {
-		BLI_linklist_free(previews, BKE_previewimg_freefunc);
-	}
 
-	BLI_strncpy(G.main->name, filename, sizeof(filename));  /* prevent G.main->name to change */
+	return nbr_entries;
 }
 
-static void filelist_from_main(struct FileList *filelist)
+#if 0
+/* Kept for reference here, in case we want to add back that feature later. We do not need it currently. */
+/* Code ***NOT*** updated for job stuff! */
+static void filelist_readjob_main_rec(struct FileList *filelist)
 {
 	ID *id;
-	struct direntry *files, *firstlib = NULL;
+	FileDirEntry *files, *firstlib = NULL;
 	ListBase *lb;
 	int a, fake, idcode, ok, totlib, totbl;
+	
+	// filelist->type = FILE_MAIN; // XXX TODO: add modes to filebrowser
 
-	// filelist->type = FILE_MAIN; // XXXXX TODO: add modes to filebrowser
+	BLI_assert(filelist->filelist.entries == NULL);
 
-	if (filelist->dir[0] == '/') filelist->dir[0] = 0;
+	if (filelist->filelist.root[0] == '/') filelist->filelist.root[0] = '\0';
 
-	if (filelist->dir[0]) {
-		idcode = groupname_to_code(filelist->dir);
-		if (idcode == 0) filelist->dir[0] = 0;
+	if (filelist->filelist.root[0]) {
+		idcode = groupname_to_code(filelist->filelist.root);
+		if (idcode == 0) filelist->filelist.root[0] = '\0';
 	}
 
 	if (filelist->dir[0] == 0) {
 		/* make directories */
 #ifdef WITH_FREESTYLE
-		filelist->numfiles = 24;
+		filelist->filelist.nbr_entries = 24;
 #else
-		filelist->numfiles = 23;
+		filelist->filelist.nbr_entries = 23;
 #endif
-		filelist->filelist = MEM_mallocN(sizeof(*filelist->filelist) * filelist->numfiles, __func__);
-
-		for (a = 0; a < filelist->numfiles; a++) {
-			memset(&(filelist->filelist[a]), 0, sizeof(struct direntry));
-			filelist->filelist[a].type |= S_IFDIR;
-		}
-
-		filelist->filelist[0].relname = BLI_strdup(FILENAME_PARENT);
-		filelist->filelist[1].relname = BLI_strdup("Scene");
-		filelist->filelist[2].relname = BLI_strdup("Object");
-		filelist->filelist[3].relname = BLI_strdup("Mesh");
-		filelist->filelist[4].relname = BLI_strdup("Curve");
-		filelist->filelist[5].relname = BLI_strdup("Metaball");
-		filelist->filelist[6].relname = BLI_strdup("Material");
-		filelist->filelist[7].relname = BLI_strdup("Texture");
-		filelist->filelist[8].relname = BLI_strdup("Image");
-		filelist->filelist[9].relname = BLI_strdup("Ika");
-		filelist->filelist[10].relname = BLI_strdup("Wave");
-		filelist->filelist[11].relname = BLI_strdup("Lattice");
-		filelist->filelist[12].relname = BLI_strdup("Lamp");
-		filelist->filelist[13].relname = BLI_strdup("Camera");
-		filelist->filelist[14].relname = BLI_strdup("Ipo");
-		filelist->filelist[15].relname = BLI_strdup("World");
-		filelist->filelist[16].relname = BLI_strdup("Screen");
-		filelist->filelist[17].relname = BLI_strdup("VFont");
-		filelist->filelist[18].relname = BLI_strdup("Text");
-		filelist->filelist[19].relname = BLI_strdup("Armature");
-		filelist->filelist[20].relname = BLI_strdup("Action");
-		filelist->filelist[21].relname = BLI_strdup("NodeTree");
-		filelist->filelist[22].relname = BLI_strdup("Speaker");
+		filelist_resize(filelist, filelist->filelist.nbr_entries);
+
+		for (a = 0; a < filelist->filelist.nbr_entries; a++) {
+			filelist->filelist.entries[a].typeflag |= FILE_TYPE_DIR;
+		}
+
+		filelist->filelist.entries[0].entry->relpath = BLI_strdup(FILENAME_PARENT);
+		filelist->filelist.entries[1].entry->relpath = BLI_strdup("Scene");
+		filelist->filelist.entries[2].entry->relpath = BLI_strdup("Object");
+		filelist->filelist.entries[3].entry->relpath = BLI_strdup("Mesh");
+		filelist->filelist.entries[4].entry->relpath = BLI_strdup("Curve");
+		filelist->filelist.entries[5].entry->relpath = BLI_strdup("Metaball");
+		filelist->filelist.entries[6].entry->relpath = BLI_strdup("Material");
+		filelist->filelist.entries[7].entry->relpath = BLI_strdup("Texture");
+		filelist->filelist.entries[8].entry->relpath = BLI_strdup("Image");
+		filelist->filelist.entries[9].entry->relpath = BLI_strdup("Ika");
+		filelist->filelist.entries[10].entry->relpath = BLI_strdup("Wave");
+		filelist->filelist.entries[11].entry->relpath = BLI_strdup("Lattice");
+		filelist->filelist.entries[12].entry->relpath = BLI_strdup("Lamp");
+		filelist->filelist.entries[13].entry->relpath = BLI_strdup("Camera");
+		filelist->filelist.entries[14].entry->relpath = BLI_strdup("Ipo");
+		filelist->filelist.entries[15].entry->relpath = BLI_strdup("World");
+		filelist->filelist.entries[16].entry->relpath = BLI_strdup("Screen");
+		filelist->filelist.entries[17].entry->relpath = BLI_strdup("VFont");
+		filelist->filelist.entries[18].entry->relpath = BLI_strdup("Text");
+		filelist->filelist.entries[19].entry->relpath = BLI_strdup("Armature");
+		filelist->filelist.entries[20].entry->relpath = BLI_strdup("Action");
+		filelist->filelist.entries[21].entry->relpath = BLI_strdup("NodeTree");
+		filelist->filelist.entries[22].entry->relpath = BLI_strdup("Speaker");
 #ifdef WITH_FREESTYLE
-		filelist->filelist[23].relname = BLI_strdup("FreestyleLineStyle");
+		filelist->filelist.entries[23].entry->relpath = BLI_strdup("FreestyleLineStyle");
 #endif
 	}
 	else {
 		/* make files */
-		idcode = groupname_to_code(filelist->dir);
+		idcode = groupname_to_code(filelist->filelist.root);
 
 		lb = which_libbase(G.main, idcode);
 		if (lb == NULL) return;
 
-		filelist->numfiles = 0;
+		filelist->filelist.nbr_entries = 0;
 		for (id = lb->first; id; id = id->next) {
-			if (!filelist->filter_data.hide_dot || id->name[2] != '.') {
-				filelist->numfiles++;
+			if (!(filelist->filter_data.flags & FLF_HIDE_DOT) || id->name[2] != '.') {
+				filelist->filelist.nbr_entries++;
 			}
 		}
 
-		/* XXXXX TODO: if databrowse F4 or append/link filelist->hide_parent has to be set */
-		if (!filelist->filter_data.hide_parent) filelist->numfiles += 1;
-		filelist->filelist = filelist->numfiles > 0 ? MEM_mallocN(sizeof(*filelist->filelist) * filelist->numfiles, __func__) : NULL;
+		/* XXX TODO: if databrowse F4 or append/link filelist->flags & FLF_HIDE_PARENT has to be set */
+		if (!(filelist->filter_data.flags & FLF_HIDE_PARENT))
+			filelist->filelist.nbr_entries++;
 
-		files = filelist->filelist;
+		if (filelist->filelist.nbr_entries > 0) {
+			filelist_resize(filelist, filelist->filelist.nbr_entries);
+		}
 
-		if (files && !filelist->filter_data.hide_parent) {
-			memset(&(filelist->filelist[0]), 0, sizeof(struct direntry));
-			filelist->filelist[0].relname = BLI_strdup(FILENAME_PARENT);
-			filelist->filelist[0].type |= S_IFDIR;
+		files = filelist->filelist.entries;
+		
+		if (!(filelist->filter_data.flags & FLF_HIDE_PARENT)) {
+			files->entry->relpath = BLI_strdup(FILENAME_PARENT);
+			files->typeflag |= FILE_TYPE_DIR;
 
 			files++;
 		}
@@ -1246,37 +2358,36 @@ static void filelist_from_main(struct FileList *filelist)
 		for (id = lb->first; id; id = id->next) {
 			ok = 1;
 			if (ok) {
-				if (files && (!filelist->filter_data.hide_dot || id->name[2] != '.')) {
-					memset(files, 0, sizeof(struct direntry));
+				if (!(filelist->filter_data.flags & FLF_HIDE_DOT) || id->name[2] != '.') {
 					if (id->lib == NULL) {
-						files->relname = BLI_strdup(id->name + 2);
+						files->entry->relpath = BLI_strdup(id->name + 2);
 					}
 					else {
-						char relname[FILE_MAX + (MAX_ID_NAME - 2) + 3];
+				        char relname[FILE_MAX + (MAX_ID_NAME - 2) + 3];
 						BLI_snprintf(relname, sizeof(relname), "%s | %s", id->lib->name, id->name + 2);
-						files->relname = BLI_strdup(relname);
+						files->entry->relpath = BLI_strdup(relname);
 					}
-					files->type |= S_IFREG;
-#if 0               /* XXXXX TODO show the selection status of the objects */
+//					files->type |= S_IFREG;
+#if 0               /* XXX TODO show the selection status of the objects */
 					if (!filelist->has_func) { /* F4 DATA BROWSE */
 						if (idcode == ID_OB) {
-							if ( ((Object *)id)->flag & SELECT) files->selflag |= FILE_SEL_SELECTED;
+							if ( ((Object *)id)->flag & SELECT) files->entry->selflag |= FILE_SEL_SELECTED;
 						}
 						else if (idcode == ID_SCE) {
-							if ( ((Scene *)id)->r.scemode & R_BG_RENDER) files->selflag |= FILE_SEL_SELECTED;
+							if ( ((Scene *)id)->r.scemode & R_BG_RENDER) files->entry->selflag |= FILE_SEL_SELECTED;
 						}
 					}
 #endif
-					files->nr = totbl + 1;
-					files->poin = id;
+//					files->entry->nr = totbl + 1;
+					files->entry->poin = id;
 					fake = id->flag & LIB_FAKEUSER;
 					if (idcode == ID_MA || idcode == ID_TE || idcode == ID_LA || idcode == ID_WO || idcode == ID_IM) {
-						files->flags |= FILE_TYPE_IMAGE;
+						files->typeflag |= FILE_TYPE_IMAGE;
 					}
-					if      (id->lib && fake) BLI_snprintf(files->extra, sizeof(files->extra), "LF %d",    id->us);
-					else if (id->lib)         BLI_snprintf(files->extra, sizeof(files->extra), "L    %d",  id->us);
-					else if (fake)            BLI_snprintf(files->extra, sizeof(files->extra), "F    %d",  id->us);
-					else                      BLI_snprintf(files->extra, sizeof(files->extra), "      %d", id->us);
+//					if      (id->lib && fake) BLI_snprintf(files->extra, sizeof(files->entry->extra), "LF %d",    id->us);
+//					else if (id->lib)         BLI_snprintf(files->extra, sizeof(files->entry->extra), "L    %d",  id->us);
+//					else if (fake)            BLI_snprintf(files->extra, sizeof(files->entry->extra), "F    %d",  id->us);
+//					else                      BLI_snprintf(files->extra, sizeof(files->entry->extra), "      %d", id->us);
 
 					if (id->lib) {
 						if (totlib == 0) firstlib = files;
@@ -1291,152 +2402,279 @@ static void filelist_from_main(struct FileList *filelist)
 
 		/* only qsort of library blocks */
 		if (totlib > 1) {
-			qsort(firstlib, totlib, sizeof(struct direntry), compare_name);
+			qsort(firstlib, totlib, sizeof(*files), compare_name);
 		}
 	}
 }
+#endif
 
-/* ********** Thumbnails job ********** */
+static void filelist_readjob_do(
+        const bool do_lib,
+        FileList *filelist, const char *main_name, short *stop, short *do_update, float *progress, ThreadMutex *lock)
+{
+	ListBase entries = {0};
+	BLI_Stack *todo_dirs;
+	TodoDir *td_dir;
+	char dir[FILE_MAX_LIBEXTRA];
+	char filter_glob[64];  /* TODO should be define! */
+	const char *root = filelist->filelist.root;
+	const int max_recursion = filelist->max_recursion;
+	int nbr_done_dirs = 0, nbr_todo_dirs = 1;
 
-typedef struct ThumbnailJob {
-	ListBase loadimages;
-	ImBuf *static_icons_buffers[BIFICONID_LAST];
-	const short *stop;
-	const short *do_update;
-	struct FileList *filelist;
-	ReportList reports;
-} ThumbnailJob;
+//	BLI_assert(filelist->filtered == NULL);
+	BLI_assert(BLI_listbase_is_empty(&filelist->filelist.entries) && (filelist->filelist.nbr_entries == 0));
 
-bool filelist_need_thumbnails(FileList *filelist)
-{
-	return filelist->need_thumbnails;
-}
+	todo_dirs = BLI_stack_new(sizeof(*td_dir), __func__);
+	td_dir = BLI_stack_push_r(todo_dirs);
+	td_dir->level = 1;
 
-static void thumbnail_joblist_free(ThumbnailJob *tj)
-{
-	FileImage *limg = tj->loadimages.first;
-	
-	/* free the images not yet copied to the filelist -> these will get freed with the filelist */
-	for (; limg; limg = limg->next) {
-		if ((limg->img) && (!limg->done)) {
-			IMB_freeImBuf(limg->img);
-		}
-	}
-	BLI_freelistN(&tj->loadimages);
-}
+	BLI_strncpy(dir, filelist->filelist.root, sizeof(dir));
+	BLI_strncpy(filter_glob, filelist->filter_data.filter_glob, sizeof(filter_glob));
 
-static void thumbnails_startjob(void *tjv, short *stop, short *do_update, float *UNUSED(progress))
-{
-	ThumbnailJob *tj = tjv;
-	FileImage *limg = tj->loadimages.first;
+	BLI_cleanup_dir(main_name, dir);
+	td_dir->dir = BLI_strdup(dir);
 
-	tj->stop = stop;
-	tj->do_update = do_update;
+	while (!BLI_stack_is_empty(todo_dirs) && !(*stop)) {
+		FileListInternEntry *entry;
+		int nbr_entries = 0;
+		bool is_lib = do_lib;
 
-	while ((*stop == 0) && (limg)) {
-		ThumbSource source = 0;
+		char *subdir;
+		int recursion_level;
+		bool skip_currpar;
 
-		BLI_assert(limg->flags & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
-		                          FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP));
-		if (limg->flags & FILE_TYPE_IMAGE) {
-			source = THB_SOURCE_IMAGE;
+		td_dir = BLI_stack_peek(todo_dirs);
+		subdir = td_dir->dir;
+		recursion_level = td_dir->level;
+		skip_currpar = (recursion_level > 1);
+
+		BLI_stack_discard(todo_dirs);
+
+		if (do_lib) {
+			nbr_entries = filelist_readjob_list_lib(subdir, &entries, skip_currpar);
 		}
-		else if (limg->flags & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) {
-			source = THB_SOURCE_BLEND;
+		if (!nbr_entries) {
+			is_lib = false;
+			nbr_entries = filelist_readjob_list_dir(subdir, &entries, filter_glob, do_lib, main_name, skip_currpar);
 		}
-		else if (limg->flags & FILE_TYPE_MOVIE) {
-			source = THB_SOURCE_MOVIE;
+
+		for (entry = entries.first; entry; entry = entry->next) {
+			BLI_join_dirfile(dir, sizeof(dir), subdir, entry->relpath);
+			BLI_cleanup_file(root, dir);
+
+			/* Generate our entry uuid. Abusing uuid as an uint64, shall be more than enough here,
+			 * things would crash way before we overflow that counter!
+			 * Using an atomic operation to avoid having to lock thread...
+			 * Note that we do not really need this here currently, since there is a single listing thread, but better
+             * remain consistent about threading! */
+			*((uint64_t *)entry->uuid) = atomic_add_uint64((uint64_t *)filelist->filelist_intern.curr_uuid, 1);
+
+			BLI_path_rel(dir, root);
+			/* Only thing we change in direntry here, so we need to free it first. */
+			MEM_freeN(entry->relpath);
+			entry->relpath = BLI_strdup(dir + 2);  /* + 2 to remove '//' added by BLI_path_rel */
+			entry->name = BLI_strdup(fileentry_uiname(root, entry->relpath, entry->typeflag, dir));
+
+			/* Here we decide whether current filedirentry is to be listed too, or not. */
+			if (max_recursion && (is_lib || (recursion_level <= max_recursion))) {
+				if (((entry->typeflag & FILE_TYPE_DIR) == 0) || FILENAME_IS_CURRPAR(entry->relpath)) {
+					/* Skip... */
+				}
+				else if (!is_lib && (recursion_level >= max_recursion) &&
+						 ((entry->typeflag & (FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP)) == 0))
+				{
+					/* Do not recurse in real directories in this case, only in .blend libs. */
+				}
+				else {
+					/* We have a directory we want to list, add it to todo list! */
+					BLI_join_dirfile(dir, sizeof(dir), root, entry->relpath);
+					BLI_cleanup_dir(main_name, dir);
+					td_dir = BLI_stack_push_r(todo_dirs);
+					td_dir->level = recursion_level + 1;
+					td_dir->dir = BLI_strdup(dir);
+					nbr_todo_dirs++;
+				}
+			}
 		}
-		else if (limg->flags & FILE_TYPE_FTFONT) {
-			source = THB_SOURCE_FONT;
+
+		if (nbr_entries) {
+			BLI_mutex_lock(lock);
+
+			*do_update = true;
+
+			BLI_movelisttolist(&filelist->filelist.entries, &entries);
+			filelist->filelist.nbr_entries += nbr_entries;
+
+			BLI_mutex_unlock(lock);
 		}
-		limg->img = IMB_thumb_manage(limg->path, THB_LARGE, source);
-		*do_update = true;
-		PIL_sleep_ms(10);
-		limg = limg->next;
+
+		nbr_done_dirs++;
+		*progress = (float)nbr_done_dirs / (float)nbr_todo_dirs;
+		MEM_freeN(subdir);
+	}
+
+	/* If we were interrupted by stop, stack may not be empty and we need to free pending dir paths. */
+	while (!BLI_stack_is_empty(todo_dirs)) {
+		td_dir = BLI_stack_peek(todo_dirs);
+		MEM_freeN(td_dir->dir);
+		BLI_stack_discard(todo_dirs);
 	}
+	BLI_stack_free(todo_dirs);
 }
 
-static void thumbnails_update(void *tjv)
+static void filelist_readjob_dir(
+        FileList *filelist, const char *main_name, short *stop, short *do_update, float *progress, ThreadMutex *lock)
 {
-	ThumbnailJob *tj = tjv;
+	filelist_readjob_do(false, filelist, main_name, stop, do_update, progress, lock);
+}
 
-	if (tj->filelist && tj->filelist->filelist) {
-		FileImage *limg = tj->loadimages.first;
-		while (limg) {
-			if (!limg->done && limg->img) {
-				tj->filelist->filelist[limg->index].image = IMB_dupImBuf(limg->img);
-				limg->done = true;
-				IMB_freeImBuf(limg->img);
-				limg->img = NULL;
-			}
-			limg = limg->next;
-		}
-	}
+static void filelist_readjob_lib(
+        FileList *filelist, const char *main_name, short *stop, short *do_update, float *progress, ThreadMutex *lock)
+{
+	filelist_readjob_do(true, filelist, main_name, stop, do_update, progress, lock);
+}
+
+static void filelist_readjob_main(
+        FileList *filelist, const char *main_name, short *stop, short *do_update, float *progress, ThreadMutex *lock)
+{
+	/* TODO! */
+	filelist_readjob_dir(filelist, main_name, stop, do_update, progress, lock);
+}
+
+
+typedef struct FileListReadJob {
+	ThreadMutex lock;
+	char main_name[FILE_MAX];
+	struct FileList *filelist;
+	struct FileList *tmp_filelist;  /* XXX We may use a simpler struct here... just a linked list and root path? */
+} FileListReadJob;
+
+static void filelist_readjob_startjob(void *flrjv, short *stop, short *do_update, float *progress)
+{
+	FileListReadJob *flrj = flrjv;
+
+//	printf("START filelist reading (%d files, main thread: %d)\n",
+//	       flrj->filelist->filelist.nbr_entries, BLI_thread_is_main());
+
+	BLI_mutex_lock(&flrj->lock);
+
+	BLI_assert((flrj->tmp_filelist == NULL) && flrj->filelist);
+
+	flrj->tmp_filelist = MEM_dupallocN(flrj->filelist);
+
+	BLI_listbase_clear(&flrj->tmp_filelist->filelist.entries);
+	flrj->tmp_filelist->filelist.nbr_entries = 0;
+
+	flrj->tmp_filelist->filelist_intern.filtered = NULL;
+	BLI_listbase_clear(&flrj->tmp_filelist->filelist_intern.entries);
+	memset(flrj->tmp_filelist->filelist_intern.curr_uuid, 0, sizeof(flrj->tmp_filelist->filelist_intern.curr_uuid));
+
+	flrj->tmp_filelist->libfiledata = NULL;
+	memset(&flrj->tmp_filelist->filelist_cache, 0, sizeof(flrj->tmp_filelist->filelist_cache));
+	flrj->tmp_filelist->selection_state = NULL;
+
+	BLI_mutex_unlock(&flrj->lock);
+
+	flrj->tmp_filelist->read_jobf(flrj->tmp_filelist, flrj->main_name, stop, do_update, progress, &flrj->lock);
 }
 
-static void thumbnails_endjob(void *tjv)
+static void filelist_readjob_update(void *flrjv)
 {
-	ThumbnailJob *tj = tjv;
+	FileListReadJob *flrj = flrjv;
+	FileListIntern *fl_intern = &flrj->filelist->filelist_intern;
+	ListBase new_entries = {NULL};
+	int nbr_entries, new_nbr_entries = 0;
+
+	BLI_movelisttolist(&new_entries, &fl_intern->entries);
+	nbr_entries = flrj->filelist->filelist.nbr_entries;
+
+	BLI_mutex_lock(&flrj->lock);
 
-	if (!*tj->stop) {
-		tj->filelist->need_thumbnails = false;
+	if (flrj->tmp_filelist->filelist.nbr_entries) {
+		/* We just move everything out of 'thread context' into final list. */
+		new_nbr_entries = flrj->tmp_filelist->filelist.nbr_entries;
+		BLI_movelisttolist(&new_entries, &flrj->tmp_filelist->filelist.entries);
+		flrj->tmp_filelist->filelist.nbr_entries = 0;
 	}
+
+	BLI_mutex_unlock(&flrj->lock);
+
+	if (new_nbr_entries) {
+		/* Do not clear selection cache, we can assume already 'selected' uuids are still valid! */
+		filelist_clear_ex(flrj->filelist, true, false);
+
+		flrj->filelist->flags |= (FL_NEED_SORTING | FL_NEED_FILTERING);
+	}
+
+	/* if no new_nbr_entries, this is NOP */
+	BLI_movelisttolist(&fl_intern->entries, &new_entries);
+	flrj->filelist->filelist.nbr_entries = nbr_entries + new_nbr_entries;
 }
 
-static void thumbnails_free(void *tjv)
+static void filelist_readjob_endjob(void *flrjv)
 {
-	ThumbnailJob *tj = tjv;
-	thumbnail_joblist_free(tj);
-	MEM_freeN(tj);
+	FileListReadJob *flrj = flrjv;
+
+	/* In case there would be some dangling update... */
+	filelist_readjob_update(flrjv);
+
+	flrj->filelist->flags &= ~FL_IS_PENDING;
+	flrj->filelist->flags |= FL_IS_READY;
 }
 
+static void filelist_readjob_free(void *flrjv)
+{
+	FileListReadJob *flrj = flrjv;
+
+//	printf("END filelist reading (%d files)\n", flrj->filelist->filelist.nbr_entries);
+
+	if (flrj->tmp_filelist) {
+		/* tmp_filelist shall never ever be filtered! */
+		BLI_assert(flrj->tmp_filelist->filelist.nbr_entries == 0);
+		BLI_assert(BLI_listbase_is_empty(&flrj->tmp_filelist->filelist.entries));
+
+		filelist_freelib(flrj->tmp_filelist);
+		filelist_free(flrj->tmp_filelist);
+		MEM_freeN(flrj->tmp_filelist);
+	}
+
+	BLI_mutex_end(&flrj->lock);
 
-void thumbnails_start(FileList *filelist, const bContext *C)
+	MEM_freeN(flrj);
+}
+
+void filelist_readjob_start(FileList *filelist, const bContext *C)
 {
 	wmJob *wm_job;
-	ThumbnailJob *tj;
-	int idx;
+	FileListReadJob *flrj;
 
 	/* prepare job data */
-	tj = MEM_callocN(sizeof(*tj), __func__);
-	tj->filelist = filelist;
-	for (idx = 0; idx < filelist->numfiles; idx++) {
-		if (!filelist->filelist[idx].path) {
-			continue;
-		}
-		if (!filelist->filelist[idx].image) {
-			if (filelist->filelist[idx].flags & (FILE_TYPE_IMAGE | FILE_TYPE_MOVIE | FILE_TYPE_FTFONT |
-			                                     FILE_TYPE_BLENDER | FILE_TYPE_BLENDER_BACKUP))
-			{
-				FileImage *limg = MEM_callocN(sizeof(*limg), __func__);
-				BLI_strncpy(limg->path, filelist->filelist[idx].path, sizeof(limg->path));
-				limg->index = idx;
-				limg->flags = filelist->filelist[idx].flags;
-				BLI_addtail(&tj->loadimages, limg);
-			}
-		}
-	}
+	flrj = MEM_callocN(sizeof(*flrj), __func__);
+	flrj->filelist = filelist;
+	BLI_strncpy(flrj->main_name, G.main->name, sizeof(flrj->main_name));
+
+	filelist->flags &= ~(FL_FORCE_RESET | FL_IS_READY);
+	filelist->flags |= FL_IS_PENDING;
 
-	BKE_reports_init(&tj->reports, RPT_PRINT);
+	BLI_mutex_init(&flrj->lock);
 
 	/* setup job */
-	wm_job = WM_jobs_get(CTX_wm_manager(C), CTX_wm_window(C), filelist, "Thumbnails",
-	                     0, WM_JOB_TYPE_FILESEL_THUMBNAIL);
-	WM_jobs_customdata_set(wm_job, tj, thumbnails_free);
-	WM_jobs_timer(wm_job, 0.5, NC_WINDOW, NC_WINDOW);
-	WM_jobs_callbacks(wm_job, thumbnails_startjob, NULL, thumbnails_update, thumbnails_endjob);
+	wm_job = WM_jobs_get(CTX_wm_manager(C), CTX_wm_window(C), CTX_wm_area(C), "Listing Dirs...",
+	                     WM_JOB_PROGRESS, WM_JOB_TYPE_FILESEL_READDIR);
+	WM_jobs_customdata_set(wm_job, flrj, filelist_readjob_free);
+	WM_jobs_timer(wm_job, 0.01, NC_SPACE | ND_SPACE_FILE_LIST, NC_SPACE | ND_SPACE_FILE_LIST);
+	WM_jobs_callbacks(wm_job, filelist_readjob_startjob, NULL, filelist_readjob_update, filelist_readjob_endjob);
 
 	/* start the job */
 	WM_jobs_start(CTX_wm_manager(C), wm_job);
 }
 
-void thumbnails_stop(wmWindowManager *wm, FileList *filelist)
+void filelist_readjob_stop(wmWindowManager *wm, ScrArea *sa)
 {
-	WM_jobs_kill_type(wm, filelist, WM_JOB_TYPE_FILESEL_THUMBNAIL);
+	WM_jobs_kill_type(wm, sa, WM_JOB_TYPE_FILESEL_READDIR);
 }
 
-int thumbnails_running(wmWindowManager *wm, FileList *filelist)
+int filelist_readjob_running(wmWindowManager *wm, ScrArea *sa)
 {
-	return WM_jobs_test(wm, filelist, WM_JOB_TYPE_FILESEL_THUMBNAIL);
+	return WM_jobs_test(wm, sa, WM_JOB_TYPE_FILESEL_READDIR);
 }
diff --git a/source/blender/editors/space_file/filelist.h b/source/blender/editors/space_file/filelist.h
index 83f7718f0de..d70faab1d6a 100644
--- a/source/blender/editors/space_file/filelist.h
+++ b/source/blender/editors/space_file/filelist.h
@@ -40,9 +40,10 @@ extern "C" {
 struct BlendHandle;
 struct FileList;
 struct FileSelection;
-struct direntry;
 struct wmWindowManager;
 
+struct FileDirEntry;
+
 typedef enum FileSelType {
 	FILE_SEL_REMOVE = 0,
 	FILE_SEL_ADD    = 1,
@@ -65,11 +66,10 @@ int                 folderlist_clear_next(struct SpaceFile *sfile);
 
 
 void                filelist_setsorting(struct FileList *filelist, const short sort);
-bool                filelist_need_sorting(struct FileList *filelist);
 void                filelist_sort(struct FileList *filelist);
 
 void                filelist_setfilter_options(struct FileList *filelist, const bool hide_dot, const bool hide_parent,
-                                               const unsigned int filter,
+                                               const unsigned int filter, const unsigned int filter_id,
                                                const char *filter_glob, const char *filter_search);
 void                filelist_filter(struct FileList *filelist);
 
@@ -77,34 +77,48 @@ void                filelist_init_icons(void);
 void                filelist_free_icons(void);
 void                filelist_imgsize(struct FileList *filelist, short w, short h);
 struct ImBuf *      filelist_getimage(struct FileList *filelist, const int index);
-struct ImBuf *      filelist_geticon(struct FileList *filelist, const int index);
+struct ImBuf *      filelist_geticon_image(struct FileList *filelist, const int index);
+int                 filelist_geticon(struct FileList *filelist, const int index, const bool is_main);
 
 struct FileList *   filelist_new(short type);
+void                filelist_clear(struct FileList *filelist);
+void                filelist_clear_ex(struct FileList *filelist, const bool do_cache, const bool do_selection);
 void                filelist_free(struct FileList *filelist);
 
 const char *        filelist_dir(struct FileList *filelist);
-void                filelist_readdir(struct FileList *filelist);
-void                filelist_setdir(struct FileList *filelist, const char *dir);
+void                filelist_setdir(struct FileList *filelist, char *r_dir);
 
+int                 filelist_files_ensure(struct FileList *filelist);
 int                 filelist_empty(struct FileList *filelist);
-int                 filelist_numfiles(struct FileList *filelist);
-struct direntry *   filelist_file(struct FileList *filelist, int index);
-int                 filelist_find(struct FileList *filelist, const char *file);
+FileDirEntry *      filelist_file(struct FileList *filelist, int index);
+int                 filelist_file_findpath(struct FileList *filelist, const char *file);
+FileDirEntry *      filelist_entry_find_uuid(struct FileList *filelist, const int uuid[4]);
+void                filelist_file_cache_slidingwindow_set(struct FileList *filelist, size_t window_size);
+bool                filelist_file_cache_block(struct FileList *filelist, const int index);
+
+bool                filelist_force_reset(struct FileList *filelist);
+bool                filelist_pending(struct FileList *filelist);
+bool                filelist_is_ready(struct FileList *filelist);
 
-short               filelist_changed(struct FileList *filelist);
+unsigned int        filelist_entry_select_set(const struct FileList *filelist, const struct FileDirEntry *entry, FileSelType select, unsigned int flag, FileCheckType check);
+void                filelist_entry_select_index_set(struct FileList *filelist, const int index, FileSelType select, unsigned int flag, FileCheckType check);
+void                filelist_entries_select_index_range_set(struct FileList *filelist, FileSelection *sel, FileSelType select, unsigned int flag, FileCheckType check);
+unsigned int        filelist_entry_select_get(struct FileList *filelist, struct FileDirEntry *entry, FileCheckType check);
+unsigned int        filelist_entry_select_index_get(struct FileList *filelist, const int index, FileCheckType check);
 
-void                filelist_select(struct FileList *filelist, FileSelection *sel, FileSelType select, unsigned int flag, FileCheckType check);
-void                filelist_select_file(struct FileList *filelist, int index, FileSelType select, unsigned int flag, FileCheckType check);
-bool                filelist_is_selected(struct FileList *filelist, int index, FileCheckType check);
+void                filelist_setrecursion(struct FileList *filelist, const int recursion_level);
 
 struct BlendHandle *filelist_lib(struct FileList *filelist);
 bool                filelist_islibrary(struct FileList *filelist, char *dir, char **group);
 void                filelist_freelib(struct FileList *filelist);
 
-bool                filelist_need_thumbnails(struct FileList *filelist);
-void                thumbnails_start(struct FileList *filelist, const struct bContext *C);
-void                thumbnails_stop(struct wmWindowManager *wm, struct FileList *filelist);
-int                 thumbnails_running(struct wmWindowManager *wm, struct FileList *filelist);
+void                filelist_readjob_start(struct FileList *filelist, const struct bContext *C);
+void                filelist_readjob_stop(struct wmWindowManager *wm, struct ScrArea *sa);
+int                 filelist_readjob_running(struct wmWindowManager *wm, struct ScrArea *sa);
+
+bool                filelist_cache_previews_update(struct FileList *filelist);
+void                filelist_cache_previews_set(struct FileList *filelist, const bool use_previews);
+bool                filelist_cache_previews_running(struct FileList *filelist);
 
 #ifdef __cplusplus
 }
diff --git a/source/blender/editors/space_file/filesel.c b/source/blender/editors/space_file/filesel.c
index 21db41b27a5..f1f202159be 100644
--- a/source/blender/editors/space_file/filesel.c
+++ b/source/blender/editors/space_file/filesel.c
@@ -163,6 +163,8 @@ short ED_fileselect_set_params(SpaceFile *sfile)
 		params->filter = 0;
 		if ((prop = RNA_struct_find_property(op->ptr, "filter_blender")))
 			params->filter |= RNA_property_boolean_get(op->ptr, prop) ? FILE_TYPE_BLENDER : 0;
+		if ((prop = RNA_struct_find_property(op->ptr, "filter_blenlib")))
+			params->filter |= RNA_property_boolean_get(op->ptr, prop) ? FILE_TYPE_BLENDERLIB : 0;
 		if ((prop = RNA_struct_find_property(op->ptr, "filter_backup")))
 			params->filter |= RNA_property_boolean_get(op->ptr, prop) ? FILE_TYPE_BLENDER_BACKUP : 0;
 		if ((prop = RNA_struct_find_property(op->ptr, "filter_image")))
@@ -200,6 +202,13 @@ short ED_fileselect_set_params(SpaceFile *sfile)
 			}
 		}
 
+		/* For now, always init filterid to 'all true' */
+		params->filter_id = FILTER_ID_AC | FILTER_ID_AR | FILTER_ID_BR | FILTER_ID_CA | FILTER_ID_CU | FILTER_ID_GD |
+		                    FILTER_ID_GR | FILTER_ID_IM | FILTER_ID_LA | FILTER_ID_LS | FILTER_ID_LT | FILTER_ID_MA |
+		                    FILTER_ID_MB | FILTER_ID_MC | FILTER_ID_ME | FILTER_ID_MSK | FILTER_ID_NT | FILTER_ID_OB |
+		                    FILTER_ID_PAL | FILTER_ID_PC | FILTER_ID_SCE | FILTER_ID_SPK | FILTER_ID_SO | FILTER_ID_TE |
+		                    FILTER_ID_TXT | FILTER_ID_VF | FILTER_ID_WO;
+
 		if (U.uiflag & USER_HIDE_DOT) {
 			params->flag |= FILE_HIDE_DOT;
 		}
@@ -292,9 +301,9 @@ void ED_fileselect_reset_params(SpaceFile *sfile)
  */
 void fileselect_file_set(SpaceFile *sfile, const int index)
 {
-	const struct direntry *file = filelist_file(sfile->files, index);
-	if (file && file->relname[0] && file->path && !BLI_is_dir(file->path)) {
-		BLI_strncpy(sfile->params->file, file->relname, FILE_MAXFILE);
+	const struct FileDirEntry *file = filelist_file(sfile->files, index);
+	if (file && file->relpath && file->relpath[0] && !(file->typeflag & FILE_TYPE_FOLDER)) {
+		BLI_strncpy(sfile->params->file, file->relpath, FILE_MAXFILE);
 	}
 }
 
@@ -446,37 +455,20 @@ float file_font_pointsize(void)
 #endif
 }
 
-static void column_widths(struct FileList *files, struct FileLayout *layout)
+static void column_widths(FileSelectParams *params, struct FileLayout *layout)
 {
 	int i;
-	int numfiles = filelist_numfiles(files);
+	const bool small_size = SMALL_SIZE_CHECK(params->thumbnail_size);
 
 	for (i = 0; i < MAX_FILE_COLUMN; ++i) {
 		layout->column_widths[i] = 0;
 	}
 
-	for (i = 0; (i < numfiles); ++i) {
-		struct direntry *file = filelist_file(files, i);
-		if (file) {
-			float len;
-			len = file_string_width(file->relname);
-			if (len > layout->column_widths[COLUMN_NAME]) layout->column_widths[COLUMN_NAME] = len;
-			len = file_string_width(file->date);
-			if (len > layout->column_widths[COLUMN_DATE]) layout->column_widths[COLUMN_DATE] = len;
-			len = file_string_width(file->time);
-			if (len > layout->column_widths[COLUMN_TIME]) layout->column_widths[COLUMN_TIME] = len;
-			len = file_string_width(file->size);
-			if (len > layout->column_widths[COLUMN_SIZE]) layout->column_widths[COLUMN_SIZE] = len;
-			len = file_string_width(file->mode1);
-			if (len > layout->column_widths[COLUMN_MODE1]) layout->column_widths[COLUMN_MODE1] = len;
-			len = file_string_width(file->mode2);
-			if (len > layout->column_widths[COLUMN_MODE2]) layout->column_widths[COLUMN_MODE2] = len;
-			len = file_string_width(file->mode3);
-			if (len > layout->column_widths[COLUMN_MODE3]) layout->column_widths[COLUMN_MODE3] = len;
-			len = file_string_width(file->owner);
-			if (len > layout->column_widths[COLUMN_OWNER]) layout->column_widths[COLUMN_OWNER] = len;
-		}
-	}
+	layout->column_widths[COLUMN_NAME] = ((float)params->thumbnail_size / 8.0f) * UI_UNIT_X;;
+	/* Biggest possible reasonable values... */
+	layout->column_widths[COLUMN_DATE] = file_string_width(small_size ? "23/08/89" : "23-Dec-89");
+	layout->column_widths[COLUMN_TIME] = file_string_width("23:59");
+	layout->column_widths[COLUMN_SIZE] = file_string_width(small_size ? "98.7 M" : "98.7 MiB");
 }
 
 void ED_fileselect_init_layout(struct SpaceFile *sfile, ARegion *ar)
@@ -496,7 +488,7 @@ void ED_fileselect_init_layout(struct SpaceFile *sfile, ARegion *ar)
 		return;
 	}
 
-	numfiles = filelist_numfiles(sfile->files);
+	numfiles = filelist_files_ensure(sfile->files);
 	textheight = (int)file_font_pointsize();
 	layout = sfile->layout;
 	layout->textheight = textheight;
@@ -535,7 +527,7 @@ void ED_fileselect_init_layout(struct SpaceFile *sfile, ARegion *ar)
 		layout->height = (int)(BLI_rctf_size_y(&v2d->cur) - 2 * layout->tile_border_y);
 		layout->rows = layout->height / (layout->tile_h + 2 * layout->tile_border_y);
 
-		column_widths(sfile->files, layout);
+		column_widths(params, layout);
 
 		if (params->display == FILE_SHORTDISPLAY) {
 			maxlen = ICON_DEFAULT_WIDTH_SCALE + column_icon_space +
@@ -545,12 +537,6 @@ void ED_fileselect_init_layout(struct SpaceFile *sfile, ARegion *ar)
 		else {
 			maxlen = ICON_DEFAULT_WIDTH_SCALE + column_icon_space +
 			         (int)layout->column_widths[COLUMN_NAME] + column_space +
-#ifndef WIN32
-			         (int)layout->column_widths[COLUMN_MODE1] + column_space +
-			         (int)layout->column_widths[COLUMN_MODE2] + column_space +
-			         (int)layout->column_widths[COLUMN_MODE3] + column_space +
-			         (int)layout->column_widths[COLUMN_OWNER] + column_space +
-#endif
 			         (int)layout->column_widths[COLUMN_DATE] + column_space +
 			         (int)layout->column_widths[COLUMN_TIME] + column_space +
 			         (int)layout->column_widths[COLUMN_SIZE] + column_space;
@@ -581,9 +567,10 @@ void ED_file_change_dir(bContext *C, const bool checkdir)
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
 	SpaceFile *sfile = CTX_wm_space_file(C);
+	ScrArea *sa = CTX_wm_area(C);
 
 	if (sfile->params) {
-		ED_fileselect_clear(wm, sfile);
+		ED_fileselect_clear(wm, sa, sfile);
 
 		/* Clear search string, it is very rare to want to keep that filter while changing dir,
 		 * and usually very annoying to keep it actually! */
@@ -610,8 +597,8 @@ int file_select_match(struct SpaceFile *sfile, const char *pattern, char *matche
 	int match = 0;
 	
 	int i;
-	struct direntry *file;
-	int n = filelist_numfiles(sfile->files);
+	FileDirEntry *file;
+	int n = filelist_files_ensure(sfile->files);
 
 	/* select any file that matches the pattern, this includes exact match 
 	 * if the user selects a single file by entering the filename
@@ -619,10 +606,10 @@ int file_select_match(struct SpaceFile *sfile, const char *pattern, char *matche
 	for (i = 0; i < n; i++) {
 		file = filelist_file(sfile->files, i);
 		/* Do not check wether file is a file or dir here! Causes T44243 (we do accept dirs at this stage). */
-		if (fnmatch(pattern, file->relname, 0) == 0) {
-			file->selflag |= FILE_SEL_SELECTED;
+		if (fnmatch(pattern, file->relpath, 0) == 0) {
+			filelist_entry_select_set(sfile->files, file, FILE_SEL_ADD, FILE_SEL_SELECTED, CHECK_ALL);
 			if (!match) {
-				BLI_strncpy(matched_file, file->relname, FILE_MAX);
+				BLI_strncpy(matched_file, file->relpath, FILE_MAX);
 			}
 			match++;
 		}
@@ -687,14 +674,12 @@ int autocomplete_file(struct bContext *C, char *str, void *UNUSED(arg_v))
 	/* search if str matches the beginning of name */
 	if (str[0] && sfile->files) {
 		AutoComplete *autocpl = UI_autocomplete_begin(str, FILE_MAX);
-		int nentries = filelist_numfiles(sfile->files);
+		int nentries = filelist_files_ensure(sfile->files);
 		int i;
 
 		for (i = 0; i < nentries; ++i) {
-			struct direntry *file = filelist_file(sfile->files, i);
-			if (file && (S_ISREG(file->type) || S_ISDIR(file->type))) {
-				UI_autocomplete_update_name(autocpl, file->relname);
-			}
+			FileDirEntry *file = filelist_file(sfile->files, i);
+			UI_autocomplete_update_name(autocpl, file->relpath);
 		}
 		match = UI_autocomplete_end(autocpl, str);
 	}
@@ -702,20 +687,20 @@ int autocomplete_file(struct bContext *C, char *str, void *UNUSED(arg_v))
 	return match;
 }
 
-void ED_fileselect_clear(struct wmWindowManager *wm, struct SpaceFile *sfile)
+void ED_fileselect_clear(wmWindowManager *wm, ScrArea *sa, SpaceFile *sfile)
 {
 	/* only NULL in rare cases - [#29734] */
 	if (sfile->files) {
-		thumbnails_stop(wm, sfile->files);
+		filelist_readjob_stop(wm, sa);
 		filelist_freelib(sfile->files);
-		filelist_free(sfile->files);
+		filelist_clear(sfile->files);
 	}
 
 	sfile->params->highlight_file = -1;
 	WM_main_add_notifier(NC_SPACE | ND_SPACE_FILE_LIST, NULL);
 }
 
-void ED_fileselect_exit(struct wmWindowManager *wm, struct SpaceFile *sfile)
+void ED_fileselect_exit(wmWindowManager *wm, ScrArea *sa, SpaceFile *sfile)
 {
 	if (!sfile) return;
 	if (sfile->op) {
@@ -727,7 +712,8 @@ void ED_fileselect_exit(struct wmWindowManager *wm, struct SpaceFile *sfile)
 	folderlist_free(sfile->folders_next);
 	
 	if (sfile->files) {
-		ED_fileselect_clear(wm, sfile);
+		ED_fileselect_clear(wm, sa, sfile);
+		filelist_free(sfile->files);
 		MEM_freeN(sfile->files);
 		sfile->files = NULL;
 	}
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index a8b71238e14..eca573c27f0 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -117,6 +117,8 @@ static void file_free(SpaceLink *sl)
 {	
 	SpaceFile *sfile = (SpaceFile *) sl;
 	
+	BLI_assert(sfile->previews_timer == NULL);
+
 	if (sfile->files) {
 		// XXXXX would need to do thumbnails_stop here, but no context available
 		filelist_freelib(sfile->files);
@@ -170,7 +172,12 @@ static void file_exit(wmWindowManager *wm, ScrArea *sa)
 {
 	SpaceFile *sfile = (SpaceFile *)sa->spacedata.first;
 
-	ED_fileselect_exit(wm, sfile);
+	if (sfile->previews_timer) {
+		WM_event_remove_timer_notifier(wm, NULL, sfile->previews_timer);
+		sfile->previews_timer = NULL;
+	}
+
+	ED_fileselect_exit(wm, sa, sfile);
 }
 
 static SpaceLink *file_duplicate(SpaceLink *sl)
@@ -211,13 +218,15 @@ static void file_refresh(const bContext *C, ScrArea *sa)
 	}
 	if (!sfile->files) {
 		sfile->files = filelist_new(params->type);
-		filelist_setdir(sfile->files, params->dir);
 		params->highlight_file = -1; /* added this so it opens nicer (ton) */
 	}
+	filelist_setdir(sfile->files, params->dir);
+	filelist_setrecursion(sfile->files, params->recursion_level);
 	filelist_setsorting(sfile->files, params->sort);
-	filelist_setfilter_options(sfile->files, params->flag & FILE_HIDE_DOT,
+	filelist_setfilter_options(sfile->files, (params->flag & FILE_HIDE_DOT) != 0,
 	                                         false, /* TODO hide_parent, should be controllable? */
 	                                         params->flag & FILE_FILTER ? params->filter : 0,
+	                                         params->filter_id,
 	                                         params->filter_glob,
 	                                         params->filter_search);
 
@@ -227,39 +236,45 @@ static void file_refresh(const bContext *C, ScrArea *sa)
 	sfile->bookmarknr = fsmenu_get_active_indices(fsmenu, FS_CATEGORY_BOOKMARKS, params->dir);
 	sfile->recentnr = fsmenu_get_active_indices(fsmenu, FS_CATEGORY_RECENT, params->dir);
 
-	if (filelist_empty(sfile->files)) {
-		thumbnails_stop(wm, sfile->files);
-		filelist_readdir(sfile->files);
-		filelist_sort(sfile->files);
-		BLI_strncpy(params->dir, filelist_dir(sfile->files), FILE_MAX);
-	}
-	else if (filelist_need_sorting(sfile->files)) {
-		thumbnails_stop(wm, sfile->files);
-		filelist_sort(sfile->files);
+	if (filelist_force_reset(sfile->files)) {
+		filelist_readjob_stop(wm, sa);
+		filelist_clear(sfile->files);
 	}
 
-	if ((params->display == FILE_IMGDISPLAY) && filelist_need_thumbnails(sfile->files)) {
-		if (!thumbnails_running(wm, sfile->files)) {
-			thumbnails_start(sfile->files, C);
+	if (filelist_empty(sfile->files)) {
+		if (!filelist_pending(sfile->files)) {
+			filelist_readjob_start(sfile->files, C);
 		}
 	}
-	else {
-		/* stop any running thumbnail jobs if we're not displaying them - speedup for NFS */
-		thumbnails_stop(wm, sfile->files);
-	}
 
+	filelist_sort(sfile->files);
 	filelist_filter(sfile->files);
 
+	if (params->display == FILE_IMGDISPLAY) {
+		filelist_cache_previews_set(sfile->files, true);
+	}
+	else {
+		filelist_cache_previews_set(sfile->files, false);
+		if (sfile->previews_timer) {
+			WM_event_remove_timer_notifier(wm, CTX_wm_window(C), sfile->previews_timer);
+			sfile->previews_timer = NULL;
+		}
+	}
+
 	if (params->renamefile[0] != '\0') {
-		int idx = filelist_find(sfile->files, params->renamefile);
+		int idx = filelist_file_findpath(sfile->files, params->renamefile);
 		if (idx >= 0) {
-			struct direntry *file = filelist_file(sfile->files, idx);
+			FileDirEntry *file = filelist_file(sfile->files, idx);
 			if (file) {
-				file->selflag |= FILE_SEL_EDITING;
+				filelist_entry_select_set(sfile->files, file, FILE_SEL_ADD, FILE_SEL_EDITING, CHECK_ALL);
 			}
 		}
 		BLI_strncpy(sfile->params->renameedit, sfile->params->renamefile, sizeof(sfile->params->renameedit));
-		params->renamefile[0] = '\0';
+		/* File listing is now async, do not clear renamefile if matching entry not found
+		 * and dirlist is not finished! */
+		if (idx >= 0 || filelist_is_ready(sfile->files)) {
+			params->renamefile[0] = '\0';
+		}
 	}
 
 	if (sfile->layout) {
@@ -278,7 +293,7 @@ static void file_refresh(const bContext *C, ScrArea *sa)
 
 static void file_listener(bScreen *UNUSED(sc), ScrArea *sa, wmNotifier *wmn)
 {
-	/* SpaceFile *sfile = (SpaceFile *)sa->spacedata.first; */
+	SpaceFile *sfile = (SpaceFile *)sa->spacedata.first;
 
 	/* context changes */
 	switch (wmn->category) {
@@ -292,6 +307,12 @@ static void file_listener(bScreen *UNUSED(sc), ScrArea *sa, wmNotifier *wmn)
 					ED_area_tag_refresh(sa);
 					ED_area_tag_redraw(sa);
 					break;
+				case ND_SPACE_FILE_PREVIEW:
+					if (filelist_cache_previews_update(sfile->files)) {
+						ED_area_tag_refresh(sa);
+						ED_area_tag_redraw(sa);
+					}
+					break;
 			}
 			break;
 	}
diff --git a/source/blender/makesdna/DNA_space_types.h b/source/blender/makesdna/DNA_space_types.h
index 2a066726d96..02a36eaef37 100644
--- a/source/blender/makesdna/DNA_space_types.h
+++ b/source/blender/makesdna/DNA_space_types.h
@@ -590,6 +590,7 @@ typedef struct FileSelectParams {
 	char filter_glob[64]; /* list of filetypes to filter */
 
 	char filter_search[64];  /* text items' name must match to be shown. */
+	int filter_id;  /* same as filter, but for ID types (aka library groups). */
 
 	int active_file;    /* active file used for keyboard navigation */
 	int highlight_file; /* file under cursor */
@@ -603,7 +604,9 @@ typedef struct FileSelectParams {
 	short flag; /* settings for filter, hiding dots files,...  */
 	short sort; /* sort order */
 	short display; /* display mode flag */
-	short filter; /* filter when (flags & FILE_FILTER) is true */
+	int filter; /* filter when (flags & FILE_FILTER) is true */
+
+	short recursion_level;  /* max number of levels in dirtree to show at once, 0 to disable recursion. */
 
 	/* XXX --- still unused -- */
 	short f_fp; /* show font preview */
@@ -635,6 +638,7 @@ typedef struct SpaceFile {
 	struct wmOperator *op; 
 
 	struct wmTimer *smoothscroll_timer;
+	struct wmTimer *previews_timer;
 
 	struct FileLayout *layout;
 	
@@ -709,7 +713,10 @@ typedef enum eFileSel_Params_Flag {
 } eFileSel_Params_Flag;
 
 
-/* files in filesel list: file types */
+/* files in filesel list: file types
+ * Note we could use mere values (instead of bitflags) for file types themselves,
+ * but since we do not lack of bytes currently...
+ */
 typedef enum eFileSel_File_Types {
 	FILE_TYPE_BLENDER           = (1 << 2),
 	FILE_TYPE_BLENDER_BACKUP    = (1 << 3),
@@ -725,6 +732,9 @@ typedef enum eFileSel_File_Types {
 	FILE_TYPE_COLLADA           = (1 << 13),
 	FILE_TYPE_OPERATOR          = (1 << 14), /* from filter_glob operator property */
 	FILE_TYPE_APPLICATIONBUNDLE = (1 << 15),
+
+	FILE_TYPE_DIR               = (1 << 30),  /* An FS directory (i.e. S_ISDIR on its path is true). */
+	FILE_TYPE_BLENDERLIB        = (1 << 31),
 } eFileSel_File_Types;
 
 /* Selection Flags in filesel: struct direntry, unsigned char selflag */
@@ -735,6 +745,117 @@ typedef enum eDirEntry_SelectFlag {
 	FILE_SEL_EDITING        = (1 << 4),
 } eDirEntry_SelectFlag;
 
+#define FILE_LIST_MAX_RECURSION 4
+
+/* ***** Related to file browser, but never saved in DNA, only here to help with RNA. ***** */
+
+/* About Unique identifier.
+ * Stored in a CustomProps once imported.
+ * Each engine is free to use it as it likes - it will be the only thing passed to it by blender to identify
+ * asset/variant/version (concatenating the three into a single 48 bytes one).
+ * Assumed to be 128bits, handled as four integers due to lack of real bytes proptype in RNA :|.
+ */
+#define ASSET_UUID_LENGTH     16
+
+/* Used to communicate with asset engines outside of 'import' context. */
+typedef struct AssetUUID {
+	int uuid_asset[4];
+	int uuid_variant[4];
+	int uuid_revision[4];
+} AssetUUID;
+
+typedef struct AssetUUIDList {
+	AssetUUID *uuids;
+	int nbr_uuids, pad;
+} AssetUUIDList;
+
+/* Container for a revision, only relevant in asset context. */
+typedef struct FileDirEntryRevision {
+	struct FileDirEntryRevision *next, *prev;
+
+	int uuid[4];
+	char *comment;
+
+	uint64_t size;
+	int64_t time;
+	/* Temp caching of UI-generated strings... */
+	char    size_str[16];
+	char    time_str[8];
+	char    date_str[16];
+} FileDirEntryRevision;
+
+/* Container for a variant, only relevant in asset context.
+ * In case there are no variants, a single one shall exist, with NULL name/description. */
+typedef struct FileDirEntryVariant {
+	struct FileDirEntryVariant *next, *prev;
+
+	int uuid[4];
+	char *name;
+	char *description;
+
+	ListBase revisions;
+	int nbr_revisions;
+	int act_revision;
+} FileDirEntryVariant;
+
+/* Container for mere direntry, with additional asset-related data. */
+typedef struct FileDirEntry {
+	struct FileDirEntry *next, *prev;
+
+	int uuid[4];
+	char *name;
+	char *description;
+
+	/* Either point to active variant/revision if available, or own entry (in mere filebrowser case). */
+	FileDirEntryRevision *entry;
+
+	int typeflag;  /* eFileSel_File_Types */
+	int blentype;  /* ID type, in case typeflag has FILE_TYPE_BLENDERLIB set. */
+
+	char *relpath;
+
+	void *poin;  /* TODO: make this a real ID pointer? */
+	struct ImBuf *image;
+
+	/* Tags are for info only, most of filtering is done in asset engine. */
+	char **tags;
+	int nbr_tags;
+
+	short status;
+	short flags;
+
+	ListBase variants;
+	int nbr_variants;
+	int act_variant;
+} FileDirEntry;
+
+/* Array of direntries. */
+/* This struct is used in various, different contexts.
+ * In Filebrowser UI, it stores the total number of available entries, the number of visible (filtered) entries,
+ *                    and a subset of those in 'entries' ListBase, from idx_start (included) to idx_end (excluded).
+ * In AssetEngine context (i.e. outside of 'browsing' context), entries contain all needed data, there is no filtering,
+ *                        so nbr_entries_filtered, entry_idx_start and entry_idx_end should all be set to -1.
+ */
+typedef struct FileDirEntryArr {
+	ListBase entries;
+	int nbr_entries;
+	int nbr_entries_filtered;
+	int entry_idx_start, entry_idx_end;
+
+	char root[1024];	 /* FILE_MAX */
+} FileDirEntryArr;
+
+/* FileDirEntry.status */
+enum {
+	ASSET_STATUS_LOCAL  = 1 << 0,  /* If active uuid is available localy/immediately. */
+	ASSET_STATUS_LATEST = 1 << 1,  /* If active uuid is latest available version. */
+};
+
+/* FileDirEntry.flags */
+enum {
+	FILE_ENTRY_INVALID_PREVIEW = 1 << 0,  /* The preview for this entry could not be generated. */
+};
+
 /* Image/UV Editor ======================================== */
 
 /* Image/UV Editor */
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index 261644c739a..864544aaddd 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -219,6 +219,16 @@ static EnumPropertyItem buttons_texture_context_items[] = {
 	{0, NULL, 0, NULL, NULL}
 };
 
+
+static EnumPropertyItem fileselectparams_recursion_level_items[] = {
+	{0, "NONE",  0, "None", "Only list current directory's content, with no recursion"},
+	{1, "BLEND", 0, "Blend File", "List .blend files' content"},
+	{2, "ALL_1", 0, "One Level", "List all sub-directories' content, one level of recursion"},
+	{3, "ALL_2", 0, "Two Levels", "List all sub-directories' content, two levels of recursion"},
+	{4, "ALL_3", 0, "Three Levels", "List all sub-directories' content, three levels of recursion"},
+	{0, NULL, 0, NULL, NULL}
+};
+
 #ifdef RNA_RUNTIME
 
 #include "DNA_anim_types.h"
@@ -1522,6 +1532,37 @@ static void rna_SpaceClipEditor_view_type_update(Main *UNUSED(bmain), Scene *UNU
 
 /* File browser. */
 
+static int rna_FileSelectParams_use_lib_get(PointerRNA *ptr)
+{
+	FileSelectParams *params = ptr->data;
+
+	return params && (params->type == FILE_LOADLIB);
+}
+
+static EnumPropertyItem *rna_FileSelectParams_recursion_level_itemf(
+        bContext *UNUSED(C), PointerRNA *ptr, PropertyRNA *UNUSED(prop), bool *r_free)
+{
+	FileSelectParams *params = ptr->data;
+
+	if (params && params->type != FILE_LOADLIB) {
+		EnumPropertyItem *item = NULL;
+		int totitem = 0;
+
+		RNA_enum_items_add_value(&item, &totitem, fileselectparams_recursion_level_items, 0);
+		RNA_enum_items_add_value(&item, &totitem, fileselectparams_recursion_level_items, 2);
+		RNA_enum_items_add_value(&item, &totitem, fileselectparams_recursion_level_items, 3);
+		RNA_enum_items_add_value(&item, &totitem, fileselectparams_recursion_level_items, 4);
+
+		RNA_enum_item_end(&item, &totitem);
+		*r_free = true;
+
+		return item;
+	}
+
+	*r_free = false;
+	return fileselectparams_recursion_level_items;
+}
+
 static void rna_FileBrowser_FSMenuEntry_path_get(PointerRNA *ptr, char *value)
 {
 	char *path = ED_fsmenu_entry_get_path(ptr->data);
@@ -3710,6 +3751,58 @@ static void rna_def_fileselect_params(BlenderRNA *brna)
 	    {0, NULL, 0, NULL, NULL}
 	};
 
+	static EnumPropertyItem file_filter_idtypes_items[] = {
+		{FILTER_ID_AC, "ACTION", ICON_ANIM_DATA, "Actions", "Show/hide Action datablocks"},
+		{FILTER_ID_AR, "ARMATURE", ICON_ARMATURE_DATA, "Armatures", "Show/hide Armature datablocks"},
+		{FILTER_ID_BR, "BRUSH", ICON_BRUSH_DATA, "Brushes", "Show/hide Brushes datablocks"},
+		{FILTER_ID_CA, "CAMERA", ICON_CAMERA_DATA, "Cameras", "Show/hide Camera datablocks"},
+		{FILTER_ID_CU, "CURVE", ICON_CURVE_DATA, "Curves", "Show/hide Curve datablocks"},
+		{FILTER_ID_GD, "GREASE_PENCIL", ICON_GREASEPENCIL, "Grease Pencil", "Show/hide Grease pencil datablocks"},
+		{FILTER_ID_GR, "GROUP", ICON_GROUP, "Groups", "Show/hide Group datablocks"},
+		{FILTER_ID_IM, "IMAGE", ICON_IMAGE_DATA, "Images", "Show/hide Image datablocks"},
+		{FILTER_ID_LA, "LAMP", ICON_LAMP_DATA, "Lamps", "Show/hide Lamp datablocks"},
+		{FILTER_ID_LS, "LINESTYLE", ICON_LINE_DATA, "Freestyle Linestyles", "Show/hide Freestyle's Line Style datablocks"},
+		{FILTER_ID_LT, "LATTICE", ICON_LATTICE_DATA, "Lattices", "Show/hide Lattice datablocks"},
+		{FILTER_ID_MA, "MATERIAL", ICON_MATERIAL_DATA, "Materials", "Show/hide Material datablocks"},
+		{FILTER_ID_MB, "METABALL", ICON_META_DATA, "Metaballs", "Show/hide Mateball datablocks"},
+		{FILTER_ID_MC, "MOVIE_CLIP", ICON_CLIP, "Movie Clips", "Show/hide Movie Clip datablocks"},
+		{FILTER_ID_ME, "MESH", ICON_MESH_DATA, "Meshes", "Show/hide Mesh datablocks"},
+		{FILTER_ID_MSK, "MASK", ICON_MOD_MASK, "Masks", "Show/hide Mask datablocks"},
+		{FILTER_ID_NT, "NODE_TREE", ICON_NODETREE, "Node Trees", "Show/hide Node Tree datablocks"},
+		{FILTER_ID_OB, "OBJECT", ICON_OBJECT_DATA, "Objects", "Show/hide Object datablocks"},
+		{FILTER_ID_PAL, "PALETTE", ICON_COLOR, "Palettes", "Show/hide Palette datablocks"},
+		{FILTER_ID_PC, "PAINT_CURVE", ICON_CURVE_BEZCURVE, "Paint Curves", "Show/hide Paint Curve datablocks"},
+		{FILTER_ID_SCE, "SCENE", ICON_SCENE_DATA, "Scenes", "Show/hide Scene datablocks"},
+		{FILTER_ID_SPK, "SPEAKER", ICON_SPEAKER, "Speakers", "Show/hide Speaker datablocks"},
+		{FILTER_ID_SO, "SOUND", ICON_SOUND, "Sounds", "Show/hide Sound datablocks"},
+		{FILTER_ID_TE, "TEXTURE", ICON_TEXTURE_DATA, "Textures", "Show/hide Texture datablocks"},
+		{FILTER_ID_TXT, "TEXT", ICON_TEXT, "Texts", "Show/hide Text datablocks"},
+		{FILTER_ID_VF, "FONT", ICON_FONT_DATA, "Fonts", "Show/hide Font datablocks"},
+		{FILTER_ID_WO, "WORLD", ICON_WORLD_DATA, "Worlds", "Show/hide World datablocks"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
+	static EnumPropertyItem file_filter_idcategories_items[] = {
+	    {FILTER_ID_SCE,
+	     "SCENE", ICON_SCENE_DATA, "Scenes", "Show/hide scenes"},
+	    {FILTER_ID_AC,
+	     "ANIMATION", ICON_ANIM_DATA, "Animations", "Show/hide animation data"},
+		{FILTER_ID_OB | FILTER_ID_GR,
+	     "OBJECT", ICON_GROUP, "Objects & Groups", "Show/hide objects and groups"},
+		{FILTER_ID_AR | FILTER_ID_CU | FILTER_ID_LT | FILTER_ID_MB | FILTER_ID_ME,
+	     "GEOMETRY", ICON_MESH_DATA, "Geometry", "Show/hide meshes, curves, lattice, armatures and metaballs data"},
+		{FILTER_ID_LS | FILTER_ID_MA | FILTER_ID_NT | FILTER_ID_TE,
+	     "SHADING", ICON_MATERIAL_DATA, "Shading",
+	     "Show/hide materials, nodetrees, textures and Freestyle's linestyles"},
+		{FILTER_ID_IM | FILTER_ID_MC | FILTER_ID_MSK | FILTER_ID_SO,
+	     "IMAGE", ICON_IMAGE_DATA, "Images & Sounds", "Show/hide images, movie clips, sounds and masks"},
+		{FILTER_ID_CA | FILTER_ID_LA | FILTER_ID_SPK | FILTER_ID_WO,
+	     "ENVIRONMENT", ICON_WORLD_DATA, "Environment", "Show/hide worlds, lamps, cameras and speakers"},
+		{FILTER_ID_BR | FILTER_ID_GD | FILTER_ID_PAL | FILTER_ID_PC | FILTER_ID_TXT | FILTER_ID_VF,
+	     "MISC", ICON_GREASEPENCIL, "Miscellaneous", "Show/hide other data types"},
+	    {0, NULL, 0, NULL, NULL}
+	};
+
 	srna = RNA_def_struct(brna, "FileSelectParams", NULL);
 	RNA_def_struct_ui_text(srna, "File Select Parameters", "File Select Parameters");
 
@@ -3728,12 +3821,23 @@ static void rna_def_fileselect_params(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "File Name", "Active file in the file browser");
 	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
 
+	prop = RNA_def_property(srna, "use_library_browsing", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_ui_text(prop, "Library Browser", "Whether we may browse blender files' content or not");
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_boolean_funcs(prop, "rna_FileSelectParams_use_lib_get", NULL);
+
 	prop = RNA_def_property(srna, "display_type", PROP_ENUM, PROP_NONE);
 	RNA_def_property_enum_sdna(prop, NULL, "display");
 	RNA_def_property_enum_items(prop, file_display_items);
 	RNA_def_property_ui_text(prop, "Display Mode", "Display mode for the file list");
 	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
 
+	prop = RNA_def_property(srna, "recursion_level", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_items(prop, fileselectparams_recursion_level_items);
+	RNA_def_property_enum_funcs(prop, NULL, NULL, "rna_FileSelectParams_recursion_level_itemf");
+	RNA_def_property_ui_text(prop, "Recursion", "Numbers of dirtree levels to show simultaneously");
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+
 	prop = RNA_def_property(srna, "use_filter", PROP_BOOLEAN, PROP_NONE);
 	RNA_def_property_boolean_sdna(prop, NULL, "flag", FILE_FILTER);
 	RNA_def_property_ui_text(prop, "Filter Files", "Enable filtering of files");
@@ -3803,7 +3907,27 @@ static void rna_def_fileselect_params(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Filter Folder", "Show folders");
 	RNA_def_property_ui_icon(prop, ICON_FILE_FOLDER, 0);
 	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
-	
+
+	prop = RNA_def_property(srna, "use_filter_blendid", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "filter", FILE_TYPE_BLENDERLIB);
+	RNA_def_property_ui_text(prop, "Filter Blender IDs", "Show .blend files items (objects, materials, etc.)");
+	RNA_def_property_ui_icon(prop, ICON_BLENDER, 0);
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+
+	prop = RNA_def_property(srna, "filter_id", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "filter_id");
+	RNA_def_property_enum_items(prop, file_filter_idtypes_items);
+	RNA_def_property_flag(prop, PROP_ENUM_FLAG);
+	RNA_def_property_ui_text(prop, "Filter ID types", "Which ID types to show/hide, when browsing a library");
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+
+	prop = RNA_def_property(srna, "filter_id_category", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "filter_id");
+	RNA_def_property_enum_items(prop, file_filter_idcategories_items);
+	RNA_def_property_flag(prop, PROP_ENUM_FLAG);
+	RNA_def_property_ui_text(prop, "Filter ID categories", "Which ID categories to show/hide, when browsing a library");
+	RNA_def_property_update(prop, NC_SPACE | ND_SPACE_FILE_PARAMS, NULL);
+
 	prop = RNA_def_property(srna, "filter_glob", PROP_STRING, PROP_NONE);
 	RNA_def_property_string_sdna(prop, NULL, "filter_glob");
 	RNA_def_property_ui_text(prop, "Extension Filter", "");
diff --git a/source/blender/windowmanager/WM_api.h b/source/blender/windowmanager/WM_api.h
index 274265773a4..745f211a0da 100644
--- a/source/blender/windowmanager/WM_api.h
+++ b/source/blender/windowmanager/WM_api.h
@@ -417,7 +417,7 @@ enum {
 	WM_JOB_TYPE_OBJECT_SIM_FLUID,
 	WM_JOB_TYPE_OBJECT_BAKE_TEXTURE,
 	WM_JOB_TYPE_OBJECT_BAKE,
-	WM_JOB_TYPE_FILESEL_THUMBNAIL,
+	WM_JOB_TYPE_FILESEL_READDIR,
 	WM_JOB_TYPE_CLIP_BUILD_PROXY,
 	WM_JOB_TYPE_CLIP_TRACK_MARKERS,
 	WM_JOB_TYPE_CLIP_SOLVE_CAMERA,
diff --git a/source/blender/windowmanager/WM_types.h b/source/blender/windowmanager/WM_types.h
index 109ccc27d79..3c0e99bddd0 100644
--- a/source/blender/windowmanager/WM_types.h
+++ b/source/blender/windowmanager/WM_types.h
@@ -361,6 +361,7 @@ typedef struct wmNotifier {
 #define ND_SPACE_NODE_VIEW		(17<<16)
 #define ND_SPACE_CHANGED		(18<<16) /*sent to a new editor type after it's replaced an old one*/
 #define ND_SPACE_CLIP			(19<<16)
+#define ND_SPACE_FILE_PREVIEW   (20<<16)
 
 /* subtype, 256 entries too */
 #define NOTE_SUBTYPE		0x0000FF00
diff --git a/source/blender/windowmanager/intern/wm_operators.c b/source/blender/windowmanager/intern/wm_operators.c
index 15aab9faa00..516164b540a 100644
--- a/source/blender/windowmanager/intern/wm_operators.c
+++ b/source/blender/windowmanager/intern/wm_operators.c
@@ -1262,6 +1262,8 @@ void WM_operator_properties_filesel(wmOperatorType *ot, int filter, short type,
 	RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 	prop = RNA_def_boolean(ot->srna, "filter_folder", (filter & FILE_TYPE_FOLDER) != 0, "Filter folders", "");
 	RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
+	prop = RNA_def_boolean(ot->srna, "filter_blenlib", (filter & FILE_TYPE_BLENDERLIB) != 0, "Filter Blender IDs", "");
+	RNA_def_property_flag(prop, PROP_HIDDEN | PROP_SKIP_SAVE);
 
 	prop = RNA_def_int(ot->srna, "filemode", type, FILE_LOADLIB, FILE_SPECIAL,
 	                   "File Browser Mode", "The setting for the file browser mode to load a .blend file, a library or a special file",
@@ -2594,28 +2596,121 @@ static short wm_link_append_flag(wmOperator *op)
 	return flag;
 }
 
-static int wm_link_append_exec(bContext *C, wmOperator *op)
+/* Helper.
+ *     if `name` is non-NULL, we assume a single-item link/append.
+ *     else if `*todo_libraries` is NULL we assume first-run.
+ */
+static void wm_link_append_do_libgroup(
+        bContext *C, wmOperator *op, const char *root, const char *libname, char *group, char *name,
+        const short flag, GSet **todo_libraries)
 {
 	Main *bmain = CTX_data_main(C);
-	Scene *scene = CTX_data_scene(C);
-	Main *mainl = NULL;
+	Main *mainl;
 	BlendHandle *bh;
 	Library *lib;
+
+	char path[FILE_MAX_LIBEXTRA], relname[FILE_MAX];
+	int idcode;
+	const bool is_first_run = (*todo_libraries == NULL);
+
+	BLI_assert(group);
+	idcode = BKE_idcode_from_name(group);
+
+	bh = BLO_blendhandle_from_file(libname, op->reports);
+
+	if (bh == NULL) {
+		/* unlikely since we just browsed it, but possible
+		 * error reports will have been made by BLO_blendhandle_from_file() */
+		return;
+	}
+
+	/* here appending/linking starts */
+	mainl = BLO_library_append_begin(bmain, &bh, libname);
+	lib = mainl->curlib;
+	BLI_assert(lib);
+
+	if (mainl->versionfile < 250) {
+		BKE_reportf(op->reports, RPT_WARNING,
+		            "Linking or appending from a very old .blend file format (%d.%d), no animation conversion will "
+		            "be done! You may want to re-save your lib file with current Blender",
+		            mainl->versionfile, mainl->subversionfile);
+	}
+
+	if (name) {
+		BLO_library_append_named_part_ex(C, mainl, &bh, name, idcode, flag);
+	}
+	else {
+		if (is_first_run) {
+			*todo_libraries = BLI_gset_new(BLI_ghashutil_strhash_p, BLI_ghashutil_strcmp, __func__);
+		}
+
+		RNA_BEGIN (op->ptr, itemptr, "files")
+		{
+			char curr_libname[FILE_MAX];
+			int curr_idcode;
+
+			RNA_string_get(&itemptr, "name", relname);
+
+			BLI_join_dirfile(path, sizeof(path), root, relname);
+
+			if (BLO_library_path_explode(path, curr_libname, &group, &name)) {
+				if (!group || !name) {
+					continue;
+				}
+
+				curr_idcode = BKE_idcode_from_name(group);
+
+				if ((idcode == curr_idcode) && (BLI_path_cmp(curr_libname, libname) == 0)) {
+					BLO_library_append_named_part_ex(C, mainl, &bh, name, idcode, flag);
+				}
+				else if (is_first_run) {
+					BLI_join_dirfile(path, sizeof(path), curr_libname, group);
+					if (!BLI_gset_haskey(*todo_libraries, path)) {
+						BLI_gset_insert(*todo_libraries, BLI_strdup(path));
+					}
+				}
+			}
+		}
+		RNA_END;
+	}
+	BLO_library_append_end(C, mainl, &bh, idcode, flag);
+
+	BLO_blendhandle_close(bh);
+
+	/* mark all library linked objects to be updated */
+	BKE_main_lib_objects_recalc_all(bmain);
+	IMB_colormanagement_check_file_config(bmain);
+
+	/* append, rather than linking */
+	if ((flag & FILE_LINK) == 0) {
+		BLI_assert(BLI_findindex(&bmain->library, lib) != -1);
+		BKE_library_make_local(bmain, lib, true);
+	}
+}
+
+static int wm_link_append_exec(bContext *C, wmOperator *op)
+{
+	Main *bmain = CTX_data_main(C);
+	Scene *scene = CTX_data_scene(C);
 	PropertyRNA *prop;
-	char name[FILE_MAX], dir[FILE_MAX], libname[FILE_MAX];
-	char *group;
-	int idcode, totfiles = 0;
+	char path[FILE_MAX_LIBEXTRA], root[FILE_MAXDIR], libname[FILE_MAX], relname[FILE_MAX];
+	char *group, *name;
+	int totfiles = 0;
 	short flag;
 
-	RNA_string_get(op->ptr, "filename", name);
-	RNA_string_get(op->ptr, "directory", dir);
+	GSet *todo_libraries = NULL;
+
+	RNA_string_get(op->ptr, "filename", relname);
+	RNA_string_get(op->ptr, "directory", root);
+
+	BLI_join_dirfile(path, sizeof(path), root, relname);
 
 	/* test if we have a valid data */
-	if (BLO_library_path_explode(dir, libname, &group, NULL) == 0) {
+	if (!BLO_library_path_explode(path, libname, &group, &name)) {
 		BKE_report(op->reports, RPT_ERROR, "Not a library");
 		return OPERATOR_CANCELLED;
 	}
-	else if ((group == NULL) || (group[0] == '\0')) {
+	else if (!group) {
 		BKE_report(op->reports, RPT_ERROR, "Nothing indicated");
 		return OPERATOR_CANCELLED;
 	}
@@ -2629,35 +2724,17 @@ static int wm_link_append_exec(bContext *C, wmOperator *op)
 	if (prop) {
 		totfiles = RNA_property_collection_length(op->ptr, prop);
 		if (totfiles == 0) {
-			if (name[0] == '\0') {
+			if (!name) {
 				BKE_report(op->reports, RPT_ERROR, "Nothing indicated");
 				return OPERATOR_CANCELLED;
 			}
 		}
 	}
-	else if (name[0] == '\0') {
+	else if (!name) {
 		BKE_report(op->reports, RPT_ERROR, "Nothing indicated");
 		return OPERATOR_CANCELLED;
 	}
 
-	bh = BLO_blendhandle_from_file(libname, op->reports);
-
-	if (bh == NULL) {
-		/* unlikely since we just browsed it, but possible
-		 * error reports will have been made by BLO_blendhandle_from_file() */
-		return OPERATOR_CANCELLED;
-	}
-
-
-	/* from here down, no error returns */
-
-	idcode = BKE_idcode_from_name(group);
-
-	/* now we have or selected, or an indicated file */
-	if (RNA_boolean_get(op->ptr, "autoselect"))
-		BKE_scene_base_deselect_all(scene);
-
-	
 	flag = wm_link_append_flag(op);
 
 	/* sanity checks for flag */
@@ -2667,46 +2744,36 @@ static int wm_link_append_exec(bContext *C, wmOperator *op)
 		flag &= ~FILE_GROUP_INSTANCE;
 	}
 
+	/* from here down, no error returns */
 
+	/* now we have or selected, or an indicated file */
+	if (RNA_boolean_get(op->ptr, "autoselect"))
+		BKE_scene_base_deselect_all(scene);
+	
 	/* tag everything, all untagged data can be made local
 	 * its also generally useful to know what is new
 	 *
 	 * take extra care BKE_main_id_flag_all(LIB_LINK_TAG, false) is called after! */
 	BKE_main_id_flag_all(bmain, LIB_PRE_EXISTING, 1);
 
-	/* here appending/linking starts */
-	mainl = BLO_library_append_begin(bmain, &bh, libname);
-	lib = mainl->curlib;
-	BLI_assert(lib);
-
-	if (mainl->versionfile < 250) {
-		BKE_reportf(op->reports, RPT_WARNING,
-		            "Linking or appending from a very old .blend file format (%d.%d), no animation conversion will "
-		            "be done! You may want to re-save your lib file with current Blender",
-		            mainl->versionfile, mainl->subversionfile);
+	if (totfiles != 0) {
+		name = NULL;
 	}
 
-	if (totfiles == 0) {
-		BLO_library_append_named_part_ex(C, mainl, &bh, name, idcode, flag);
-	}
-	else {
-		RNA_BEGIN (op->ptr, itemptr, "files")
-		{
-			RNA_string_get(&itemptr, "name", name);
-			BLO_library_append_named_part_ex(C, mainl, &bh, name, idcode, flag);
+	wm_link_append_do_libgroup(C, op, root, libname, group, name, flag, &todo_libraries);
+
+	if (todo_libraries) {
+		GSetIterator libs_it;
+
+		GSET_ITER(libs_it, todo_libraries) {
+			char *libpath = (char *)BLI_gsetIterator_getKey(&libs_it);
+
+			BLO_library_path_explode(libpath, libname, &group, NULL);
+
+			wm_link_append_do_libgroup(C, op, root, libname, group, NULL, flag, &todo_libraries);
 		}
-		RNA_END;
-	}
-	BLO_library_append_end(C, mainl, &bh, idcode, flag);
-	
-	/* mark all library linked objects to be updated */
-	BKE_main_lib_objects_recalc_all(bmain);
-	IMB_colormanagement_check_file_config(bmain);
 
-	/* append, rather than linking */
-	if ((flag & FILE_LINK) == 0) {
-		BLI_assert(BLI_findindex(&bmain->library, lib) != -1);
-		BKE_library_make_local(bmain, lib, true);
+		BLI_gset_free(todo_libraries, MEM_freeN);
 	}
 
 	/* important we unset, otherwise these object wont
@@ -2718,10 +2785,9 @@ static int wm_link_append_exec(bContext *C, wmOperator *op)
 	
 	/* free gpu materials, some materials depend on existing objects, such as lamps so freeing correctly refreshes */
 	GPU_materials_free();
-	BLO_blendhandle_close(bh);
 
 	/* XXX TODO: align G.lib with other directory storage (like last opened image etc...) */
-	BLI_strncpy(G.lib, dir, FILE_MAX);
+	BLI_strncpy(G.lib, root, FILE_MAX);
 
 	WM_event_add_notifier(C, NC_WINDOW, NULL);
 
@@ -2761,7 +2827,7 @@ static void WM_OT_link(wmOperatorType *ot)
 	ot->flag |= OPTYPE_UNDO;
 
 	WM_operator_properties_filesel(
-	        ot, FILE_TYPE_FOLDER | FILE_TYPE_BLENDER, FILE_LOADLIB, FILE_OPENFILE,
+	        ot, FILE_TYPE_FOLDER | FILE_TYPE_BLENDER | FILE_TYPE_BLENDERLIB, FILE_LOADLIB, FILE_OPENFILE,
 	        WM_FILESEL_FILEPATH | WM_FILESEL_DIRECTORY | WM_FILESEL_FILENAME | WM_FILESEL_RELPATH | WM_FILESEL_FILES,
 	        FILE_DEFAULTDISPLAY);
 	
@@ -2781,7 +2847,7 @@ static void WM_OT_append(wmOperatorType *ot)
 	ot->flag |= OPTYPE_UNDO;
 
 	WM_operator_properties_filesel(
-		ot, FILE_TYPE_FOLDER | FILE_TYPE_BLENDER, FILE_LOADLIB, FILE_OPENFILE,
+		ot, FILE_TYPE_FOLDER | FILE_TYPE_BLENDER | FILE_TYPE_BLENDERLIB, FILE_LOADLIB, FILE_OPENFILE,
 		WM_FILESEL_FILEPATH | WM_FILESEL_DIRECTORY | WM_FILESEL_FILENAME | WM_FILESEL_FILES,
 		FILE_DEFAULTDISPLAY);