IMB_metadata improvements

- Metadata handling is now separate from `ImBuf *`, allowing it to be
  used with a generic `IDProperty *`.
- Merged `IMB_metadata_add_field()` and `IMB_metadata_change_field()`
  into a more robust `IMB_metadata_set_field()`. This new function
  doesn't return any status (it now always succeeds, and the previously
  existing return value was never checked anyway).
- Removed `IMB_metadata_del_field()` as it was never actually used
  anywhere.
- Use `IMB_metadata_ensure()` instead of having
  `IMB_metadata_set_field()` create the containing `IDProperty` for
  you.
- Deduplicated function declarations, moved `intern/IMB_metadata.h` out
  of `intern/`. Note that this does mean that we have some extra
  `#include "IMB_metadata.h"` lines now, as the metadata functions are
  no longer declared in `IMB_imbuf.h`.
- Deduplicated function declarations, all metadata-related declarations
  are now in imbuf/IMB_metadata.h.

Part of: https://developer.blender.org/D2273

Reviewed by: @campbellbarton

1 files changed, 10 insertions, 9 deletions

diff --git a/source/blender/imbuf/intern/thumbs.c b/source/blender/imbuf/intern/thumbs.c
index 3c587684641..2fa5b5a0170 100644
--- a/source/blender/imbuf/intern/thumbs.c
+++ b/source/blender/imbuf/intern/thumbs.c
@@ -430,16 +430,17 @@ static ImBuf *thumb_create_ex(
 			IMB_scaleImBuf(img, ex, ey);
 		}
 		BLI_snprintf(desc, sizeof(desc), "Thumbnail for %s", uri);
-		IMB_metadata_change_field(img, "Description", desc);
-		IMB_metadata_change_field(img, "Software", "Blender");
-		IMB_metadata_change_field(img, "Thumb::URI", uri);
-		IMB_metadata_change_field(img, "Thumb::MTime", mtime);
+		IMB_metadata_ensure(&img->metadata);
+		IMB_metadata_set_field(img->metadata, "Software", "Blender");
+		IMB_metadata_set_field(img->metadata, "Thumb::URI", uri);
+		IMB_metadata_set_field(img->metadata, "Description", desc);
+		IMB_metadata_set_field(img->metadata, "Thumb::MTime", mtime);
 		if (use_hash) {
-			IMB_metadata_change_field(img, "X-Blender::Hash", hash);
+			IMB_metadata_set_field(img->metadata, "X-Blender::Hash", hash);
 		}
 		if (ELEM(source, THB_SOURCE_IMAGE, THB_SOURCE_BLEND, THB_SOURCE_FONT)) {
-			IMB_metadata_change_field(img, "Thumb::Image::Width", cwidth);
-			IMB_metadata_change_field(img, "Thumb::Image::Height", cheight);
+			IMB_metadata_set_field(img->metadata, "Thumb::Image::Width", cwidth);
+			IMB_metadata_set_field(img->metadata, "Thumb::Image::Height", cheight);
 		}
 		img->ftype = IMB_FTYPE_PNG;
 		img->planes = 32;
@@ -589,7 +590,7 @@ ImBuf *IMB_thumb_manage(const char *org_path, ThumbSize size, ThumbSource source
 
 				const bool use_hash = thumbhash_from_path(file_path, source, thumb_hash);
 
-				if (IMB_metadata_get_field(img, "Thumb::MTime", mtime, sizeof(mtime))) {
+				if (IMB_metadata_get_field(img->metadata, "Thumb::MTime", mtime, sizeof(mtime))) {
 					regenerate = (st.st_mtime != atol(mtime));
 				}
 				else {
@@ -598,7 +599,7 @@ ImBuf *IMB_thumb_manage(const char *org_path, ThumbSize size, ThumbSource source
 				}
 
 				if (use_hash && !regenerate) {
-					if (IMB_metadata_get_field(img, "X-Blender::Hash", thumb_hash_curr, sizeof(thumb_hash_curr))) {
+					if (IMB_metadata_get_field(img->metadata, "X-Blender::Hash", thumb_hash_curr, sizeof(thumb_hash_curr))) {
 						regenerate = !STREQ(thumb_hash, thumb_hash_curr);
 					}
 					else {