Refactor ID copying (and to some extent, ID freeing).

This will allow much finer controll over how we copy data-blocks, from
full copy in Main database, to "lighter" ones (out of Main, inside an
already allocated datablock, etc.).

This commit also transfers a llot of what was previously handled by
per-ID-type custom code to generic ID handling code in BKE_library.
Hopefully will avoid in future inconsistencies and missing bits we had
all over the codebase in the past.

It also adds missing copying handling for a few types, most notably
Scene (which where using a fully customized handling previously).

Note that the type of allocation used during copying (regular in Main,
allocated but outside of Main, or not allocated by ID handling code at
all) is stored in ID's, which allows to handle them correctly when
freeing. This needs to be taken care of with caution when doing 'weird'
unusual things with ID copying and/or allocation!

As a final note, while rather noisy, this commit will hopefully not
break too much existing branches, old 'API' has been kept for the main
part, as a wrapper around new code. Cleaning it up will happen later.

Design task : T51804
Phab Diff: D2714

1 files changed, 41 insertions, 24 deletions

diff --git a/source/blender/blenkernel/intern/paint.c b/source/blender/blenkernel/intern/paint.c
index c7cfe55f659..9fc2136df86 100644
--- a/source/blender/blenkernel/intern/paint.c
+++ b/source/blender/blenkernel/intern/paint.c
@@ -309,24 +309,31 @@ PaintCurve *BKE_paint_curve_add(Main *bmain, const char *name)
 {
 	PaintCurve *pc;
 
-	pc = BKE_libblock_alloc(bmain, ID_PC, name);
+	pc = BKE_libblock_alloc(bmain, ID_PC, name, 0);
 
 	return pc;
 }
 
-PaintCurve *BKE_paint_curve_copy(Main *bmain, const PaintCurve *pc)
+/**
+ * Only copy internal data of PaintCurve ID from source to already allocated/initialized destination.
+ * You probably nerver want to use that directly, use id_copy or BKE_id_copy_ex for typical needs.
+ *
+ * WARNING! This function will not handle ID user count!
+ *
+ * \param flag  Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
+ */
+void BKE_paint_curve_copy_data(Main *UNUSED(bmain), PaintCurve *pc_dst, const PaintCurve *pc_src, const int UNUSED(flag))
 {
-	PaintCurve *pc_new;
-
-	pc_new = BKE_libblock_copy(bmain, &pc->id);
-
-	if (pc->tot_points != 0) {
-		pc_new->points = MEM_dupallocN(pc->points);
+	if (pc_src->tot_points != 0) {
+		pc_dst->points = MEM_dupallocN(pc_src->points);
 	}
+}
 
-	BKE_id_copy_ensure_local(bmain, &pc->id, &pc_new->id);
-
-	return pc_new;
+PaintCurve *BKE_paint_curve_copy(Main *bmain, const PaintCurve *pc)
+{
+	PaintCurve *pc_copy;
+	BKE_id_copy_ex(bmain, &pc->id, (ID **)&pc_copy, 0, false);
+	return pc_copy;
 }
 
 void BKE_paint_curve_make_local(Main *bmain, PaintCurve *pc, const bool lib_local)
@@ -388,7 +395,7 @@ Palette *BKE_palette_add(Main *bmain, const char *name)
 {
 	Palette *palette;
 
-	palette = BKE_libblock_alloc(bmain, ID_PAL, name);
+	palette = BKE_libblock_alloc(bmain, ID_PAL, name, 0);
 
 	/* enable fake user by default */
 	id_fake_user_set(&palette->id);
@@ -396,17 +403,24 @@ Palette *BKE_palette_add(Main *bmain, const char *name)
 	return palette;
 }
 
-Palette *BKE_palette_copy(Main *bmain, const Palette *palette)
+/**
+ * Only copy internal data of Palette ID from source to already allocated/initialized destination.
+ * You probably nerver want to use that directly, use id_copy or BKE_id_copy_ex for typical needs.
+ *
+ * WARNING! This function will not handle ID user count!
+ *
+ * \param flag  Copying options (see BKE_library.h's LIB_ID_COPY_... flags for more).
+ */
+void BKE_palette_copy_data(Main *UNUSED(bmain), Palette *palette_dst, const Palette *palette_src, const int UNUSED(flag))
 {
-	Palette *palette_new;
-
-	palette_new = BKE_libblock_copy(bmain, &palette->id);
-
-	BLI_duplicatelist(&palette_new->colors, &palette->colors);
-
-	BKE_id_copy_ensure_local(bmain, &palette->id, &palette_new->id);
+	BLI_duplicatelist(&palette_dst->colors, &palette_src->colors);
+}
 
-	return palette_new;
+Palette *BKE_palette_copy(Main *bmain, const Palette *palette)
+{
+	Palette *palette_copy;
+	BKE_id_copy_ex(bmain, &palette->id, (ID **)&palette_copy, 0, false);
+	return palette_copy;
 }
 
 void BKE_palette_make_local(Main *bmain, Palette *palette, const bool lib_local)
@@ -537,12 +551,15 @@ void BKE_paint_free(Paint *paint)
  * still do a id_us_plus(), rather then if we were copying between 2 existing
  * scenes where a matching value should decrease the existing user count as
  * with paint_brush_set() */
-void BKE_paint_copy(Paint *src, Paint *tar)
+void BKE_paint_copy(Paint *src, Paint *tar, const int flag)
 {
 	tar->brush = src->brush;
-	id_us_plus((ID *)tar->brush);
-	id_us_plus((ID *)tar->palette);
 	tar->cavity_curve = curvemapping_copy(src->cavity_curve);
+
+	if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) == 0) {
+		id_us_plus((ID *)tar->brush);
+		id_us_plus((ID *)tar->palette);
+	}
 }
 
 void BKE_paint_stroke_get_average(Scene *scene, Object *ob, float stroke[3])