Image cache rewrite to using generic movie cache

Summary:
Behaves very much the same as cache for Movie Clip datablock:

- Image now have `MovieCache *cache` field which replaced
  legacy `ListBase ibufs`.

  This allows image datablock to easily keep of image
  buffers which are owned by itself. This field isn't
  saved to the file and getting restored on undo steps.

  However, cache limit is global for movies, sequences
  and image datablocks now. So overall cached image buffers
  size will not go above cache limit size in user
  preferences.

- Image buffers which are marked as BITMAPDIRTY will never
  be freed from the cache.

- Added utility function to iterate over image buffers
  saved in movie cache.

- Movie cache cleanup check callback now have ImBuf argument
  which can be used in a condition of cleanup.

- Added some utility functions which replaces legacy ibufs
  iterations with image cache iteration which happens from
  inside a lock.

- Fixed `image_mem_size()` which was only counting one of
  the buffers if both float and byte buffer present.

Additional notes:

- `BKE_image_get_first_ibuf()` is rather stupid, but direct
  access to ibufs->first was also the same stupid idea.

  Would consider avoid this function is another project.

- There are some places which doesn't look threadsafe, but
  they already were not so much threadsafe anyway before.

  So think not a big deal with solving this later.

Finally solves infinite memory usage by image sequences! :)

Reviewers: brecht, campbellbarton

Reviewed By: brecht

CC: sebastian_k

Differential Revision: http://developer.blender.org/D95

2 files changed, 11 insertions, 4 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image.c b/source/blender/editors/sculpt_paint/paint_image.c
index 47ca3e5ce0c..5b323a0a396 100644
--- a/source/blender/editors/sculpt_paint/paint_image.c
+++ b/source/blender/editors/sculpt_paint/paint_image.c
@@ -250,6 +250,7 @@ void ED_image_undo_restore(bContext *C, ListBase *lb)
 
 	for (tile = lb->first; tile; tile = tile->next) {
 		short use_float;
+		bool need_release = true;
 
 		/* find image based on name, pointer becomes invalid with global undo */
 		if (ima && strcmp(tile->idname, ima->id.name) == 0) {
@@ -268,8 +269,9 @@ void ED_image_undo_restore(bContext *C, ListBase *lb)
 			 * matched file name in list of already loaded images */
 
 			BKE_image_release_ibuf(ima, ibuf, NULL);
+			need_release = false;
 
-			ibuf = BLI_findstring(&ima->ibufs, tile->ibufname, offsetof(ImBuf, name));
+			ibuf = BKE_image_get_ibuf_with_name(ima, tile->ibufname);
 		}
 
 		if (!ima || !ibuf || !(ibuf->rect || ibuf->rect_float)) {
@@ -298,7 +300,12 @@ void ED_image_undo_restore(bContext *C, ListBase *lb)
 			ibuf->userflags |= IB_MIPMAP_INVALID;  /* force mipmap recreatiom */
 		ibuf->userflags |= IB_DISPLAY_BUFFER_INVALID;
 
-		BKE_image_release_ibuf(ima, ibuf, NULL);
+		if (need_release) {
+			BKE_image_release_ibuf(ima, ibuf, NULL);
+		}
+		else {
+			IMB_freeImBuf(ibuf);
+		}
 	}
 
 	IMB_freeImBuf(tmpibuf);
diff --git a/source/blender/editors/sculpt_paint/paint_image_proj.c b/source/blender/editors/sculpt_paint/paint_image_proj.c
index d6989c082a1..4b402bc1741 100644
--- a/source/blender/editors/sculpt_paint/paint_image_proj.c
+++ b/source/blender/editors/sculpt_paint/paint_image_proj.c
@@ -542,8 +542,7 @@ static bool project_paint_PickColor(const ProjPaintState *ps, const float pt[2],
 	}
 
 	ima = project_paint_face_image(ps, ps->dm_mtface, face_index);
-	ibuf = ima->ibufs.first; /* we must have got the imbuf before getting here */
-	if (!ibuf) return 0;
+	ibuf = BKE_image_get_first_ibuf(ima); /* we must have got the imbuf before getting here */
 
 	if (interp) {
 		float x, y;
@@ -599,6 +598,7 @@ static bool project_paint_PickColor(const ProjPaintState *ps, const float pt[2],
 			}
 		}
 	}
+	IMB_freeImBuf(ibuf);
 	return 1;
 }