LibOverride: Make diffing several times faster.

Diffing on undo steps is a critical performance point of override
system, although not required for override itself, it gives user
immediate feedback ove what is overridden.

Profiling showed that rna path text search over overrides operations was
by far the most costly thing here, so now using a runtime temp ghash
mapping for this search instead.

Seems to give at least 5 times speedup on big production rig.

4 files changed, 42 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/library_override.c b/source/blender/blenkernel/intern/library_override.c
index 4f10a5bca6b..ae6d1c26a2b 100644
--- a/source/blender/blenkernel/intern/library_override.c
+++ b/source/blender/blenkernel/intern/library_override.c
@@ -36,6 +36,7 @@
 #include "BKE_main.h"
 
 #include "BLI_utildefines.h"
+#include "BLI_ghash.h"
 #include "BLI_listbase.h"
 #include "BLI_string.h"
 
@@ -148,6 +149,10 @@ void BKE_override_library_clear(IDOverrideLibrary *override, const bool do_id_us
 {
   BLI_assert(override != NULL);
 
+  if (override->runtime != NULL) {
+    BLI_ghash_clear(override->runtime, NULL, NULL);
+  }
+
   for (IDOverrideLibraryProperty *op = override->properties.first; op; op = op->next) {
     bke_override_property_clear(op);
   }
@@ -164,6 +169,11 @@ void BKE_override_library_free(struct IDOverrideLibrary **override, const bool d
 {
   BLI_assert(*override != NULL);
 
+  if ((*override)->runtime != NULL) {
+    BLI_ghash_free((*override)->runtime, NULL, NULL);
+    (*override)->runtime = NULL;
+  }
+
   BKE_override_library_clear(*override, do_id_user);
   MEM_freeN(*override);
   *override = NULL;
@@ -285,15 +295,28 @@ bool BKE_override_library_create_from_tag(Main *bmain)
   return ret;
 }
 
+/* We only build override GHash on request. */
+BLI_INLINE IDOverrideLibraryRuntime *override_library_rna_path_mapping_ensure(
+    IDOverrideLibrary *override)
+{
+  if (override->runtime == NULL) {
+    override->runtime = BLI_ghash_new(BLI_ghashutil_strhash_p, BLI_ghashutil_strcmp, __func__);
+    for (IDOverrideLibraryProperty *op = override->properties.first; op != NULL; op = op->next) {
+      BLI_ghash_insert(override->runtime, op->rna_path, op);
+    }
+  }
+
+  return override->runtime;
+}
+
 /**
  * Find override property from given RNA path, if it exists.
  */
 IDOverrideLibraryProperty *BKE_override_library_property_find(IDOverrideLibrary *override,
                                                               const char *rna_path)
 {
-  /* XXX TODO we'll most likely want a runtime ghash to store that mapping at some point. */
-  return BLI_findstring_ptr(
-      &override->properties, rna_path, offsetof(IDOverrideLibraryProperty, rna_path));
+  IDOverrideLibraryRuntime *override_runtime = override_library_rna_path_mapping_ensure(override);
+  return BLI_ghash_lookup(override_runtime, rna_path);
 }
 
 /**
@@ -303,7 +326,6 @@ IDOverrideLibraryProperty *BKE_override_library_property_get(IDOverrideLibrary *
                                                              const char *rna_path,
                                                              bool *r_created)
 {
-  /* XXX TODO we'll most likely want a runtime ghash to store that mapping at some point. */
   IDOverrideLibraryProperty *op = BKE_override_library_property_find(override, rna_path);
 
   if (op == NULL) {
@@ -311,6 +333,10 @@ IDOverrideLibraryProperty *BKE_override_library_property_get(IDOverrideLibrary *
     op->rna_path = BLI_strdup(rna_path);
     BLI_addtail(&override->properties, op);
 
+    IDOverrideLibraryRuntime *override_runtime = override_library_rna_path_mapping_ensure(
+        override);
+    BLI_ghash_insert(override_runtime, op->rna_path, op);
+
     if (r_created) {
       *r_created = true;
     }
@@ -355,6 +381,9 @@ void BKE_override_library_property_delete(IDOverrideLibrary *override,
                                           IDOverrideLibraryProperty *override_property)
 {
   bke_override_property_clear(override_property);
+  if (override->runtime != NULL) {
+    BLI_ghash_remove(override->runtime, override_property->rna_path, NULL, NULL);
+  }
   BLI_freelinkN(&override->properties, override_property);
 }
 
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index f6c1cd0380a..145d36626c1 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -2668,6 +2668,7 @@ static void direct_link_id(FileData *fd, ID *id)
   if (id->override_library) {
     id->override_library = newdataadr(fd, id->override_library);
     link_list_ex(fd, &id->override_library->properties, direct_link_id_override_property_cb);
+    id->override_library->runtime = NULL;
   }
 
   DrawDataList *drawdata = DRW_drawdatalist_from_id(id);
diff --git a/source/blender/makesdna/DNA_ID.h b/source/blender/makesdna/DNA_ID.h
index f303f7720c3..fce68b11fe4 100644
--- a/source/blender/makesdna/DNA_ID.h
+++ b/source/blender/makesdna/DNA_ID.h
@@ -32,6 +32,7 @@ extern "C" {
 #endif
 
 struct FileData;
+struct GHash;
 struct GPUTexture;
 struct ID;
 struct Library;
@@ -206,6 +207,9 @@ typedef struct IDOverrideLibraryProperty {
   ListBase operations;
 } IDOverrideLibraryProperty;
 
+/* We do not need a full struct for that currently, just a GHash. */
+typedef struct GHash IDOverrideLibraryRuntime;
+
 /* Main container for all overriding data info of a data-block. */
 typedef struct IDOverrideLibrary {
   /** Reference linked ID which this one overrides. */
@@ -220,6 +224,8 @@ typedef struct IDOverrideLibrary {
   /* Temp ID storing extra override data (used for differential operations only currently).
    * Always NULL outside of read/write context. */
   struct ID *storage;
+
+  IDOverrideLibraryRuntime *runtime;
 } IDOverrideLibrary;
 
 enum eOverrideLibrary_Flag {
diff --git a/source/blender/makesrna/intern/rna_access_compare_override.c b/source/blender/makesrna/intern/rna_access_compare_override.c
index 7dae3cbf339..c3a81f0c6e1 100644
--- a/source/blender/makesrna/intern/rna_access_compare_override.c
+++ b/source/blender/makesrna/intern/rna_access_compare_override.c
@@ -27,6 +27,8 @@
 #include "BLI_utildefines.h"
 #include "BLI_string.h"
 
+#define DEBUG_OVERRIDE_TIMEIT
+
 #ifdef DEBUG_OVERRIDE_TIMEIT
 #  include "PIL_time_utildefines.h"
 #endif