ID-Remap - Step one: core work (cleanup and rework of generic ID datablock handling).

This commit changes a lot of how IDs are handled internally, especially the unlinking/freeing
processes. So far, this was very fuzy, to summarize cleanly deleting or replacing a datablock
was pretty much impossible, except for a few special cases.

Also, unlinking was handled by each datatype, in a rather messy and prone-to-errors way (quite
a few ID usages were missed or wrongly handled that way).

One of the main goal of id-remap branch was to cleanup this, and fatorize ID links handling
by using library_query utils to allow generic handling of those, which is now the case
(now, generic ID links handling is only "knwon" from readfile.c and library_query.c).

This commit also adds backends to allow live replacement and deletion of datablocks in Blender
(so-called 'remapping' process, where we replace all usages of a given ID pointer by a new one,
or NULL one in case of unlinking).

This will allow nice new features, like ability to easily reload or relocate libraries, real immediate
deletion of datablocks in blender, replacement of one datablock by another, etc.
Some of those are for next commits.

A word of warning: this commit is highly risky, because it affects potentially a lot in Blender core.
Though it was tested rather deeply, being totally impossible to check all possible ID usage cases,
it's likely there are some remaining issues and bugs in new code... Please report them! ;)

Review task: D2027 (https://developer.blender.org/D2027).
Reviewed by campbellbarton, thanks a bunch.

1 files changed, 2 insertions, 268 deletions

diff --git a/source/blender/blenkernel/intern/library.c b/source/blender/blenkernel/intern/library.c
index 961b45df4e6..fe16df18813 100644
--- a/source/blender/blenkernel/intern/library.c
+++ b/source/blender/blenkernel/intern/library.c
@@ -84,7 +84,6 @@
 #include "BKE_context.h"
 #include "BKE_curve.h"
 #include "BKE_depsgraph.h"
-#include "BKE_fcurve.h"
 #include "BKE_font.h"
 #include "BKE_global.h"
 #include "BKE_group.h"
@@ -92,7 +91,6 @@
 #include "BKE_idcode.h"
 #include "BKE_idprop.h"
 #include "BKE_image.h"
-#include "BKE_ipo.h"
 #include "BKE_key.h"
 #include "BKE_lamp.h"
 #include "BKE_lattice.h"
@@ -103,16 +101,12 @@
 #include "BKE_material.h"
 #include "BKE_main.h"
 #include "BKE_mball.h"
-#include "BKE_movieclip.h"
 #include "BKE_mask.h"
 #include "BKE_node.h"
 #include "BKE_object.h"
-#include "BKE_paint.h"
 #include "BKE_particle.h"
 #include "BKE_packedFile.h"
 #include "BKE_speaker.h"
-#include "BKE_sound.h"
-#include "BKE_screen.h"
 #include "BKE_scene.h"
 #include "BKE_text.h"
 #include "BKE_texture.h"
@@ -125,10 +119,6 @@
 #include "IMB_imbuf.h"
 #include "IMB_imbuf_types.h"
 
-#ifdef WITH_PYTHON
-#include "BPY_extern.h"
-#endif
-
 /* GS reads the memory pointed at in a specific ordering. 
  * only use this definition, makes little and big endian systems
  * work fine, in conjunction with MAKE_ID */
@@ -182,7 +172,6 @@ void id_us_ensure_real(ID *id)
 	}
 }
 
-/* Unused currently... */
 void id_us_clear_real(ID *id)
 {
 	if (id && (id->tag & LIB_TAG_EXTRAUSER)) {
@@ -232,9 +221,7 @@ void id_us_min(ID *id)
 		if (id->us <= limit) {
 			printf("ID user decrement error: %s (from '%s'): %d <= %d\n",
 			       id->name, id->lib ? id->lib->filepath : "[Main]", id->us, limit);
-			/* We cannot assert here, because of how we 'delete' datablocks currently (setting their usercount to zero),
-			 * this is weak but it's how it works for now. */
-			/* BLI_assert(0); */
+			BLI_assert(0);
 			id->us = limit;
 		}
 		else {
@@ -462,37 +449,6 @@ bool id_copy(ID *id, ID **newid, bool test)
 	return false;
 }
 
-bool id_unlink(ID *id, int test)
-{
-	Main *mainlib = G.main;
-	short type = GS(id->name);
-
-	switch (type) {
-		case ID_TXT:
-			if (test) return true;
-			BKE_text_unlink(mainlib, (Text *)id);
-			break;
-		case ID_GR:
-			if (test) return true;
-			BKE_group_unlink(mainlib, (Group *)id);
-			break;
-		case ID_OB:
-			if (test) return true;
-			BKE_object_unlink(mainlib, (Object *)id);
-			break;
-	}
-
-	if (id->us == 0) {
-		if (test) return true;
-
-		BKE_libblock_free(mainlib, id);
-
-		return true;
-	}
-
-	return false;
-}
-
 bool id_single_user(bContext *C, ID *id, PointerRNA *ptr, PropertyRNA *prop)
 {
 	ID *newid = NULL;
@@ -1111,234 +1067,12 @@ void BKE_libblock_relink(ID *id)
 	BKE_library_foreach_ID_link(id, id_relink_looper, NULL, 0);
 }
 
-static void BKE_library_free(Library *lib)
+void BKE_library_free(Library *lib)
 {
 	if (lib->packedfile)
 		freePackedFile(lib->packedfile);
 }
 
-static BKE_library_free_window_manager_cb free_windowmanager_cb = NULL;
-
-void BKE_library_callback_free_window_manager_set(BKE_library_free_window_manager_cb func)
-{
-	free_windowmanager_cb = func;
-}
-
-static BKE_library_free_notifier_reference_cb free_notifier_reference_cb = NULL;
-
-void BKE_library_callback_free_notifier_reference_set(BKE_library_free_notifier_reference_cb func)
-{
-	free_notifier_reference_cb = func;
-}
-
-static BKE_library_free_editor_id_reference_cb free_editor_id_reference_cb = NULL;
-
-void BKE_library_callback_free_editor_id_reference_set(BKE_library_free_editor_id_reference_cb func)
-{
-	free_editor_id_reference_cb = func;
-}
-
-static void animdata_dtar_clear_cb(ID *UNUSED(id), AnimData *adt, void *userdata)
-{
-	ChannelDriver *driver;
-	FCurve *fcu;
-
-	/* find the driver this belongs to and update it */
-	for (fcu = adt->drivers.first; fcu; fcu = fcu->next) {
-		driver = fcu->driver;
-		
-		if (driver) {
-			DriverVar *dvar;
-			for (dvar = driver->variables.first; dvar; dvar = dvar->next) {
-				DRIVER_TARGETS_USED_LOOPER(dvar) 
-				{
-					if (dtar->id == userdata)
-						dtar->id = NULL;
-				}
-				DRIVER_TARGETS_LOOPER_END
-			}
-		}
-	}
-}
-
-void BKE_libblock_free_data(Main *bmain, ID *id)
-{
-	if (id->properties) {
-		IDP_FreeProperty(id->properties);
-		MEM_freeN(id->properties);
-	}
-	
-	/* this ID may be a driver target! */
-	BKE_animdata_main_cb(bmain, animdata_dtar_clear_cb, (void *)id);
-}
-
-/* used in headerbuttons.c image.c mesh.c screen.c sound.c and library.c */
-void BKE_libblock_free_ex(Main *bmain, void *idv, bool do_id_user)
-{
-	ID *id = idv;
-	short type = GS(id->name);
-	ListBase *lb = which_libbase(bmain, type);
-
-	DAG_id_type_tag(bmain, type);
-
-#ifdef WITH_PYTHON
-	BPY_id_release(id);
-#endif
-
-	switch (type) {    /* GetShort from util.h */
-		case ID_SCE:
-			BKE_scene_free((Scene *)id);
-			break;
-		case ID_LI:
-			BKE_library_free((Library *)id);
-			break;
-		case ID_OB:
-			BKE_object_free_ex((Object *)id, do_id_user);
-			break;
-		case ID_ME:
-			BKE_mesh_free((Mesh *)id, 1);
-			break;
-		case ID_CU:
-			BKE_curve_free((Curve *)id);
-			break;
-		case ID_MB:
-			BKE_mball_free((MetaBall *)id);
-			break;
-		case ID_MA:
-			BKE_material_free((Material *)id);
-			break;
-		case ID_TE:
-			BKE_texture_free((Tex *)id);
-			break;
-		case ID_IM:
-			BKE_image_free((Image *)id);
-			break;
-		case ID_LT:
-			BKE_lattice_free((Lattice *)id);
-			break;
-		case ID_LA:
-			BKE_lamp_free((Lamp *)id);
-			break;
-		case ID_CA:
-			BKE_camera_free((Camera *) id);
-			break;
-		case ID_IP:
-			BKE_ipo_free((Ipo *)id);
-			break;
-		case ID_KE:
-			BKE_key_free((Key *)id);
-			break;
-		case ID_WO:
-			BKE_world_free((World *)id);
-			break;
-		case ID_SCR:
-			BKE_screen_free((bScreen *)id);
-			break;
-		case ID_VF:
-			BKE_vfont_free((VFont *)id);
-			break;
-		case ID_TXT:
-			BKE_text_free((Text *)id);
-			break;
-		case ID_SPK:
-			BKE_speaker_free((Speaker *)id);
-			break;
-		case ID_SO:
-			BKE_sound_free((bSound *)id);
-			break;
-		case ID_GR:
-			BKE_group_free((Group *)id);
-			break;
-		case ID_AR:
-			BKE_armature_free((bArmature *)id);
-			break;
-		case ID_AC:
-			BKE_action_free((bAction *)id);
-			break;
-		case ID_NT:
-			ntreeFreeTree_ex((bNodeTree *)id, do_id_user);
-			break;
-		case ID_BR:
-			BKE_brush_free((Brush *)id);
-			break;
-		case ID_PA:
-			BKE_particlesettings_free((ParticleSettings *)id);
-			break;
-		case ID_WM:
-			if (free_windowmanager_cb)
-				free_windowmanager_cb(NULL, (wmWindowManager *)id);
-			break;
-		case ID_GD:
-			BKE_gpencil_free((bGPdata *)id);
-			break;
-		case ID_MC:
-			BKE_movieclip_free((MovieClip *)id);
-			break;
-		case ID_MSK:
-			BKE_mask_free(bmain, (Mask *)id);
-			break;
-		case ID_LS:
-			BKE_linestyle_free((FreestyleLineStyle *)id);
-			break;
-		case ID_PAL:
-			BKE_palette_free((Palette *)id);
-			break;
-		case ID_PC:
-			BKE_paint_curve_free((PaintCurve *)id);
-			break;
-	}
-
-	/* avoid notifying on removed data */
-	BKE_main_lock(bmain);
-
-	if (free_notifier_reference_cb) {
-		free_notifier_reference_cb(id);
-	}
-
-	if (free_editor_id_reference_cb) {
-		free_editor_id_reference_cb(id);
-	}
-
-	BLI_remlink(lb, id);
-
-	BKE_libblock_free_data(bmain, id);
-	BKE_main_unlock(bmain);
-
-	MEM_freeN(id);
-}
-
-void BKE_libblock_free(Main *bmain, void *idv)
-{
-	BKE_libblock_free_ex(bmain, idv, true);
-}
-
-void BKE_libblock_free_us(Main *bmain, void *idv)      /* test users */
-{
-	ID *id = idv;
-	
-	id_us_min(id);
-
-	/* XXX This is a temp (2.77) hack so that we keep same behavior as in 2.76 regarding groups when deleting an object.
-	 *     Since only 'user_one' usage of objects is groups, and only 'real user' usage of objects is scenes,
-	 *     removing that 'user_one' tag when there is no more real (scene) users of an object ensures it gets
-	 *     fully unlinked.
-	 *     Otherwise, there is no real way to get rid of an object anymore - better handling of this is TODO.
-	 */
-	if ((GS(id->name) == ID_OB) && (id->us == 1)) {
-		id_us_clear_real(id);
-	}
-
-	if (id->us == 0) {
-		switch (GS(id->name)) {
-			case ID_OB:
-				BKE_object_unlink(bmain, (Object *)id);
-				break;
-		}
-		
-		BKE_libblock_free(bmain, id);
-	}
-}
-
 Main *BKE_main_new(void)
 {
 	Main *bmain = MEM_callocN(sizeof(Main), "new main");