T39690: Modifications to Blender's 'temp dir' system.

Current temporary data of Blender suffers one major issue - default 'temp' dir on Windows is never
automatically cleaned up, and can end being quite big when used by Blender, especially when we have
to store per-process data (using getpid() in file names).

To address this, this patch:
* Divides tempdir paths in two, one for 'base' temp dir (the same as previous unique tempdir path),
  the other is a mkdtemp-generated sub-dir, specific to each Blender instance.
* Only uses base tempdir when we need some shallow persistance accross Blender sessions - and we always
  reuse the same filename (quit.blend...) or generate small file (crash reports...).
* Uses temp sub-dir for heavy files like pointcache or renderEXRs (Save Buffer option).
* Erases temp sub-dir on quit or crash.

To get this working it also adds a working 'recursive delete' to BLI_delete() under Windows.

Note that, as in current code, the 'recover render result' hack-feature that was possible
with SaveBuffer option is still removed. A real renderresult cache feature will be added
soon, though.

Reviewers: campbellbarton, brecht, sergey

Reviewed By: campbellbarton, sergey

CC: sergey

Differential Revision: https://developer.blender.org/D531

1 files changed, 66 insertions, 12 deletions

diff --git a/source/blender/blenlib/intern/path_util.c b/source/blender/blenlib/intern/path_util.c
index e00631fe996..d95cb5e5ee1 100644
--- a/source/blender/blenlib/intern/path_util.c
+++ b/source/blender/blenlib/intern/path_util.c
@@ -49,9 +49,9 @@
 
 #include "GHOST_Path-api.h"
 
-#ifdef WIN32
-#  include "MEM_guardedalloc.h"
+#include "MEM_guardedalloc.h"
 
+#ifdef WIN32
 #  include "utf_winfunc.h"
 #  include "utfconv.h"
 #  include <io.h>
@@ -73,7 +73,8 @@
 
 static char bprogname[FILE_MAX];    /* full path to program executable */
 static char bprogdir[FILE_MAX];     /* full path to directory in which executable is located */
-static char btempdir[FILE_MAX];     /* temporary directory */
+static char btempdir_base[FILE_MAX];          /* persistent temporary directory */
+static char btempdir_session[FILE_MAX] = "";  /* volatile temporary directory */
 
 /* implementation */
 
@@ -2319,14 +2320,21 @@ const char *BLI_program_dir(void)
  * 
  * Also make sure the temp dir has a trailing slash
  *
- * \param fullname The full path to the temp directory
+ * \param fullname The full path to the temporary temp directory
+ * \param basename The full path to the persistent temp directory (may be NULL)
  * \param maxlen The size of the fullname buffer
  * \param userdir Directory specified in user preferences 
  */
-static void BLI_where_is_temp(char *fullname, const size_t maxlen, char *userdir)
+static void BLI_where_is_temp(char *fullname, char *basename, const size_t maxlen, char *userdir)
 {
+	/* Clear existing temp dir, if needed. */
+	BLI_temp_dir_session_purge();
+
 	fullname[0] = '\0';
-	
+	if (basename) {
+		basename[0] = '\0';
+	}
+
 	if (userdir && BLI_is_dir(userdir)) {
 		BLI_strncpy(fullname, userdir, maxlen);
 	}
@@ -2368,23 +2376,59 @@ static void BLI_where_is_temp(char *fullname, const size_t maxlen, char *userdir
 		}
 #endif
 	}
+
+	/* Now that we have a valid temp dir, add system-generated unique sub-dir. */
+	if (basename) {
+		/* 'XXXXXX' is kind of tag to be replaced by mktemp-familly by an uuid. */
+		char *tmp_name = BLI_strdupcat(fullname, "blender_XXXXXX");
+		const size_t ln = strlen(tmp_name) + 1;
+		if (ln <= maxlen) {
+#ifdef WIN32
+			if (_mktemp_s(tmp_name, ln) == 0) {
+				BLI_dir_create_recursive(tmp_name);
+			}
+#else
+			mkdtemp(tmp_name);
+#endif
+		}
+		if (BLI_is_dir(tmp_name)) {
+			BLI_strncpy(basename, fullname, maxlen);
+			BLI_strncpy(fullname, tmp_name, maxlen);
+			BLI_add_slash(fullname);
+		}
+		else {
+			printf("Warning! Could not generate a temp file name for '%s', falling back to '%s'\n", tmp_name, fullname);
+		}
+
+		MEM_freeN(tmp_name);
+	}
 }
 
 /**
- * Sets btempdir to userdir if specified and is a valid directory, otherwise
+ * Sets btempdir_base to userdir if specified and is a valid directory, otherwise
  * chooses a suitable OS-specific temporary directory.
+ * Sets btempdir_session to a mkdtemp-generated sub-dir of btempdir_base.
  */
-void BLI_init_temporary_dir(char *userdir)
+void BLI_temp_dir_init(char *userdir)
 {
-	BLI_where_is_temp(btempdir, FILE_MAX, userdir);
+	BLI_where_is_temp(btempdir_session, btempdir_base, FILE_MAX, userdir);
+;
 }
 
 /**
  * Path to temporary directory (with trailing slash)
  */
-const char *BLI_temporary_dir(void)
+const char *BLI_temp_dir_session(void)
+{
+	return btempdir_session[0] ? btempdir_session : BLI_temp_dir_base();
+}
+
+/**
+ * Path to persistent temporary directory (with trailing slash)
+ */
+const char *BLI_temp_dir_base(void)
 {
-	return btempdir;
+	return btempdir_base;
 }
 
 /**
@@ -2392,7 +2436,17 @@ const char *BLI_temporary_dir(void)
  */
 void BLI_system_temporary_dir(char *dir)
 {
-	BLI_where_is_temp(dir, FILE_MAX, NULL);
+	BLI_where_is_temp(dir, NULL, FILE_MAX, NULL);
+}
+
+/**
+ * Delete content of this instance's temp dir.
+ */
+void BLI_temp_dir_session_purge(void)
+{
+	if (btempdir_session[0] && BLI_is_dir(btempdir_session)) {
+		BLI_delete(btempdir_session, true, true);
+	}
 }
 
 #ifdef WITH_ICONV