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, 31 insertions, 442 deletions

diff --git a/source/blender/blenkernel/intern/object.c b/source/blender/blenkernel/intern/object.c
index 65ee153e00b..d4ba70ee0a6 100644
--- a/source/blender/blenkernel/intern/object.c
+++ b/source/blender/blenkernel/intern/object.c
@@ -317,14 +317,14 @@ void BKE_object_free_derived_caches(Object *ob)
 	if (ob->type == OB_MESH) {
 		Mesh *me = ob->data;
 
-		if (me->bb) {
+		if (me && me->bb) {
 			me->bb->flag |= BOUNDBOX_DIRTY;
 		}
 	}
 	else if (ELEM(ob->type, OB_SURF, OB_CURVE, OB_FONT)) {
 		Curve *cu = ob->data;
 
-		if (cu->bb) {
+		if (cu && cu->bb) {
 			cu->bb->flag |= BOUNDBOX_DIRTY;
 		}
 	}
@@ -393,77 +393,52 @@ void BKE_object_free_caches(Object *object)
 	}
 }
 
-/* do not free object itself */
-void BKE_object_free_ex(Object *ob, bool do_id_user)
+/** Free (or release) any data used by this object (does not free the object itself). */
+void BKE_object_free(Object *ob)
 {
-	int a;
-	
+	BKE_animdata_free((ID *)ob, false);
+
 	BKE_object_free_modifiers(ob);
-	
-	/* disconnect specific data, but not for lib data (might be indirect data, can get relinked) */
-	if (ob->data) {
-		ID *id = ob->data;
-		id_us_min(id);
-		if (id->us == 0 && id->lib == NULL) {
-			switch (ob->type) {
-				case OB_MESH:
-					BKE_mesh_unlink((Mesh *)id);
-					break;
-				case OB_CURVE:
-					BKE_curve_unlink((Curve *)id);
-					break;
-				case OB_MBALL:
-					BKE_mball_unlink((MetaBall *)id);
-					break;
-			}
-		}
-		ob->data = NULL;
-	}
 
-	if (ob->mat) {
-		for (a = 0; a < ob->totcol; a++) {
-			if (ob->mat[a])
-				id_us_min(&ob->mat[a]->id);
-		}
-		MEM_freeN(ob->mat);
+	MEM_SAFE_FREE(ob->mat);
+	MEM_SAFE_FREE(ob->matbits);
+	MEM_SAFE_FREE(ob->iuser);
+	MEM_SAFE_FREE(ob->bb);
+
+	BLI_freelistN(&ob->defbase);
+	if (ob->pose) {
+		BKE_pose_free_ex(ob->pose, false);
+		ob->pose = NULL;
 	}
-	if (ob->matbits) MEM_freeN(ob->matbits);
-	ob->mat = NULL;
-	ob->matbits = NULL;
-	if (ob->iuser) MEM_freeN(ob->iuser);
-	ob->iuser = NULL;
-	if (ob->bb) MEM_freeN(ob->bb); 
-	ob->bb = NULL;
-	if (ob->adt) BKE_animdata_free((ID *)ob);
-	if (ob->poselib)
-		id_us_min(&ob->poselib->id);
-	if (ob->gpd)
-		id_us_min(&ob->gpd->id);
-	if (ob->defbase.first)
-		BLI_freelistN(&ob->defbase);
-	if (ob->pose)
-		BKE_pose_free_ex(ob->pose, do_id_user);
-	if (ob->mpath)
+	if (ob->mpath) {
 		animviz_free_motionpath(ob->mpath);
+		ob->mpath = NULL;
+	}
 	BKE_bproperty_free_list(&ob->prop);
-	
+
 	free_sensors(&ob->sensors);
 	free_controllers(&ob->controllers);
 	free_actuators(&ob->actuators);
 	
-	BKE_constraints_free_ex(&ob->constraints, do_id_user);
+	BKE_constraints_free_ex(&ob->constraints, false);
 	
 	free_partdeflect(ob->pd);
 	BKE_rigidbody_free_object(ob);
 	BKE_rigidbody_free_constraint(ob);
 
-	if (ob->soft) sbFree(ob->soft);
-	if (ob->bsoft) bsbFree(ob->bsoft);
-	if (ob->gpulamp.first) GPU_lamp_free(ob);
+	if (ob->soft) {
+		sbFree(ob->soft);
+		ob->soft = NULL;
+	}
+	if (ob->bsoft) {
+		bsbFree(ob->bsoft);
+		ob->bsoft = NULL;
+	}
+	GPU_lamp_free(ob);
 
 	BKE_sculptsession_free(ob);
 
-	if (ob->pc_ids.first) BLI_freelistN(&ob->pc_ids);
+	BLI_freelistN(&ob->pc_ids);
 
 	BLI_freelistN(&ob->lodlevels);
 
@@ -473,398 +448,12 @@ void BKE_object_free_ex(Object *ob, bool do_id_user)
 		if (ob->curve_cache->path)
 			free_path(ob->curve_cache->path);
 		MEM_freeN(ob->curve_cache);
+		ob->curve_cache = NULL;
 	}
 
 	BKE_previewimg_free(&ob->preview);
 }
 
-void BKE_object_free(Object *ob)
-{
-	BKE_object_free_ex(ob, true);
-}
-
-static void unlink_object__unlinkModifierLinks(void *userData, Object *ob, Object **obpoin, int UNUSED(cd_flag))
-{
-	Object *unlinkOb = userData;
-
-	if (*obpoin == unlinkOb) {
-		*obpoin = NULL;
-		// XXX: should this just be OB_RECALC_DATA?
-		DAG_id_tag_update(&ob->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
-	}
-}
-
-void BKE_object_unlink(Main *bmain, Object *ob)
-{
-	Object *obt;
-	Material *mat;
-	World *wrld;
-	bScreen *sc;
-	Scene *sce;
-	SceneRenderLayer *srl;
-	FreestyleLineSet *lineset;
-	bNodeTree *ntree;
-	Curve *cu;
-	Tex *tex;
-	Group *group;
-	Camera *camera;
-	bConstraint *con;
-	//bActionStrip *strip; // XXX animsys 
-	ModifierData *md;
-	ARegion *ar;
-	RegionView3D *rv3d;
-	LodLevel *lod;
-	int a, found;
-	
-	unlink_controllers(&ob->controllers);
-	unlink_actuators(&ob->actuators);
-	
-	/* check all objects: parents en bevels and fields, also from libraries */
-	/* FIXME: need to check all animation blocks (drivers) */
-	obt = bmain->object.first;
-	while (obt) {
-		if (obt->proxy == ob)
-			obt->proxy = NULL;
-		if (obt->proxy_from == ob) {
-			obt->proxy_from = NULL;
-			DAG_id_tag_update(&obt->id, OB_RECALC_OB);
-		}
-		if (obt->proxy_group == ob)
-			obt->proxy_group = NULL;
-		
-		if (obt->parent == ob) {
-			obt->parent = NULL;
-			DAG_id_tag_update(&obt->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
-		}
-		
-		modifiers_foreachObjectLink(obt, unlink_object__unlinkModifierLinks, ob);
-		
-		if (ELEM(obt->type, OB_CURVE, OB_FONT)) {
-			cu = obt->data;
-
-			if (cu->bevobj == ob) {
-				cu->bevobj = NULL;
-				DAG_id_tag_update(&obt->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
-			}
-			if (cu->taperobj == ob) {
-				cu->taperobj = NULL;
-				DAG_id_tag_update(&obt->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
-			}
-			if (cu->textoncurve == ob) {
-				cu->textoncurve = NULL;
-				DAG_id_tag_update(&obt->id, OB_RECALC_OB | OB_RECALC_DATA | OB_RECALC_TIME);
-			}
-		}
-		else if (obt->type == OB_ARMATURE && obt->pose) {
-			bPoseChannel *pchan;
-			for (pchan = obt->pose->chanbase.first; pchan; pchan = pchan->next) {
-				for (con = pchan->constraints.first; con; con = con->next) {
-					const bConstraintTypeInfo *cti = BKE_constraint_typeinfo_get(con);
-					ListBase targets = {NULL, NULL};
-					bConstraintTarget *ct;
-					
-					if (cti && cti->get_constraint_targets) {
-						cti->get_constraint_targets(con, &targets);
-						
-						for (ct = targets.first; ct; ct = ct->next) {
-							if (ct->tar == ob) {
-								ct->tar = NULL;
-								ct->subtarget[0] = '\0';
-								DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-							}
-						}
-						
-						if (cti->flush_constraint_targets)
-							cti->flush_constraint_targets(con, &targets, 0);
-					}
-				}
-				if (pchan->custom == ob)
-					pchan->custom = NULL;
-			}
-		}
-		else if (ELEM(OB_MBALL, ob->type, obt->type)) {
-			if (BKE_mball_is_basis_for(obt, ob))
-				DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-		}
-		
-		sca_remove_ob_poin(obt, ob);
-		
-		for (con = obt->constraints.first; con; con = con->next) {
-			const bConstraintTypeInfo *cti = BKE_constraint_typeinfo_get(con);
-			ListBase targets = {NULL, NULL};
-			bConstraintTarget *ct;
-			
-			if (cti && cti->get_constraint_targets) {
-				cti->get_constraint_targets(con, &targets);
-				
-				for (ct = targets.first; ct; ct = ct->next) {
-					if (ct->tar == ob) {
-						ct->tar = NULL;
-						ct->subtarget[0] = '\0';
-						DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-					}
-				}
-				
-				if (cti->flush_constraint_targets)
-					cti->flush_constraint_targets(con, &targets, 0);
-			}
-		}
-		
-		/* object is deflector or field */
-		if (ob->pd) {
-			if (obt->soft)
-				DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-
-			/* cloth */
-			for (md = obt->modifiers.first; md; md = md->next)
-				if (md->type == eModifierType_Cloth)
-					DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-		}
-		
-		/* strips */
-#if 0 // XXX old animation system
-		for (strip = obt->nlastrips.first; strip; strip = strip->next) {
-			if (strip->object == ob)
-				strip->object = NULL;
-			
-			if (strip->modifiers.first) {
-				bActionModifier *amod;
-				for (amod = strip->modifiers.first; amod; amod = amod->next)
-					if (amod->ob == ob)
-						amod->ob = NULL;
-			}
-		}
-#endif // XXX old animation system
-
-		/* particle systems */
-		if (obt->particlesystem.first) {
-			ParticleSystem *tpsys = obt->particlesystem.first;
-			for (; tpsys; tpsys = tpsys->next) {
-				BoidState *state = NULL;
-				BoidRule *rule = NULL;
-
-				ParticleTarget *pt = tpsys->targets.first;
-				for (; pt; pt = pt->next) {
-					if (pt->ob == ob) {
-						pt->ob = NULL;
-						DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-						break;
-					}
-				}
-
-				if (tpsys->target_ob == ob) {
-					tpsys->target_ob = NULL;
-					DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-				}
-
-				if (tpsys->part->dup_ob == ob)
-					tpsys->part->dup_ob = NULL;
-
-				if (tpsys->part->phystype == PART_PHYS_BOIDS) {
-					ParticleData *pa;
-					BoidParticle *bpa;
-					int p;
-
-					for (p = 0, pa = tpsys->particles; p < tpsys->totpart; p++, pa++) {
-						bpa = pa->boid;
-						if (bpa->ground == ob)
-							bpa->ground = NULL;
-					}
-				}
-				if (tpsys->part->boids) {
-					for (state = tpsys->part->boids->states.first; state; state = state->next) {
-						for (rule = state->rules.first; rule; rule = rule->next) {
-							if (rule->type == eBoidRuleType_Avoid) {
-								BoidRuleGoalAvoid *gabr = (BoidRuleGoalAvoid *)rule;
-								if (gabr->ob == ob)
-									gabr->ob = NULL;
-							}
-							else if (rule->type == eBoidRuleType_FollowLeader) {
-								BoidRuleFollowLeader *flbr = (BoidRuleFollowLeader *)rule;
-								if (flbr->ob == ob)
-									flbr->ob = NULL;
-							}
-						}
-					}
-				}
-				
-				if (tpsys->parent == ob)
-					tpsys->parent = NULL;
-			}
-			if (ob->pd)
-				DAG_id_tag_update(&obt->id, OB_RECALC_DATA);
-		}
-
-		/* levels of detail */
-		for (lod = obt->lodlevels.first; lod; lod = lod->next) {
-			if (lod->source == ob)
-				lod->source = NULL;
-		}
-
-		obt = obt->id.next;
-	}
-	
-	/* materials */
-	for (mat = bmain->mat.first; mat; mat = mat->id.next) {
-		if (mat->nodetree) {
-			ntreeSwitchID(mat->nodetree, &ob->id, NULL);
-		}
-		for (a = 0; a < MAX_MTEX; a++) {
-			if (mat->mtex[a] && ob == mat->mtex[a]->object) {
-				/* actually, test for lib here... to do */
-				mat->mtex[a]->object = NULL;
-			}
-		}
-	}
-
-	/* node trees */
-	for (ntree = bmain->nodetree.first; ntree; ntree = ntree->id.next) {
-		if (ntree->type == NTREE_SHADER)
-			ntreeSwitchID(ntree, &ob->id, NULL);
-	}
-	
-	/* textures */
-	for (tex = bmain->tex.first; tex; tex = tex->id.next) {
-		if (tex->env && (ob == tex->env->object)) tex->env->object = NULL;
-		if (tex->pd  && (ob == tex->pd->object)) tex->pd->object = NULL;
-		if (tex->vd  && (ob == tex->vd->object)) tex->vd->object = NULL;
-	}
-
-	/* worlds */
-	wrld = bmain->world.first;
-	while (wrld) {
-		if (wrld->id.lib == NULL) {
-			for (a = 0; a < MAX_MTEX; a++) {
-				if (wrld->mtex[a] && ob == wrld->mtex[a]->object)
-					wrld->mtex[a]->object = NULL;
-			}
-		}
-		
-		wrld = wrld->id.next;
-	}
-		
-	/* scenes */
-	sce = bmain->scene.first;
-	while (sce) {
-		if (sce->id.lib == NULL) {
-			if (sce->camera == ob) sce->camera = NULL;
-			if (sce->toolsettings->skgen_template == ob) sce->toolsettings->skgen_template = NULL;
-			if (sce->toolsettings->particle.object == ob) sce->toolsettings->particle.object = NULL;
-			if (sce->toolsettings->particle.shape_object == ob) sce->toolsettings->particle.shape_object = NULL;
-
-#ifdef DURIAN_CAMERA_SWITCH
-			{
-				TimeMarker *m;
-
-				for (m = sce->markers.first; m; m = m->next) {
-					if (m->camera == ob)
-						m->camera = NULL;
-				}
-			}
-#endif
-			if (sce->ed) {
-				Sequence *seq;
-				SEQ_BEGIN(sce->ed, seq)
-				{
-					if (seq->scene_camera == ob) {
-						seq->scene_camera = NULL;
-					}
-				}
-				SEQ_END
-			}
-
-			for (srl = sce->r.layers.first; srl; srl = srl->next) {
-				for (lineset = (FreestyleLineSet *)srl->freestyleConfig.linesets.first;
-				     lineset; lineset = lineset->next)
-				{
-					if (lineset->linestyle) {
-						BKE_linestyle_target_object_unlink(lineset->linestyle, ob);
-					}
-				}
-			}
-		}
-
-		sce = sce->id.next;
-	}
-	
-	/* screens */
-	sc = bmain->screen.first;
-	while (sc) {
-		ScrArea *sa = sc->areabase.first;
-		while (sa) {
-			SpaceLink *sl;
-
-			for (sl = sa->spacedata.first; sl; sl = sl->next) {
-				if (sl->spacetype == SPACE_VIEW3D) {
-					View3D *v3d = (View3D *) sl;
-
-					/* found doesn't need to be set here */
-					if (v3d->ob_centre == ob) {
-						v3d->ob_centre = NULL;
-						v3d->ob_centre_bone[0] = '\0';
-					}
-					if (v3d->localvd && v3d->localvd->ob_centre == ob) {
-						v3d->localvd->ob_centre = NULL;
-						v3d->localvd->ob_centre_bone[0] = '\0';
-					}
-
-					found = 0;
-					if (v3d->camera == ob) {
-						v3d->camera = NULL;
-						found = 1;
-					}
-					if (v3d->localvd && v3d->localvd->camera == ob) {
-						v3d->localvd->camera = NULL;
-						found += 2;
-					}
-
-					if (found) {
-						if (sa->spacetype == SPACE_VIEW3D) {
-							for (ar = sa->regionbase.first; ar; ar = ar->next) {
-								if (ar->regiontype == RGN_TYPE_WINDOW) {
-									rv3d = (RegionView3D *)ar->regiondata;
-									if (found == 1 || found == 3) {
-										if (rv3d->persp == RV3D_CAMOB)
-											rv3d->persp = RV3D_PERSP;
-									}
-									if (found == 2 || found == 3) {
-										if (rv3d->localvd && rv3d->localvd->persp == RV3D_CAMOB)
-											rv3d->localvd->persp = RV3D_PERSP;
-									}
-								}
-							}
-						}
-					}
-				}
-#if 0
-				else if (ELEM(sl->spacetype, SPACE_OUTLINER, SPACE_BUTS, SPACE_NODE)) {
-					/* now handled by WM_main_remove_editor_id_reference */
-				}
-#endif
-			}
-
-			sa = sa->next;
-		}
-		sc = sc->id.next;
-	}
-
-	/* groups */
-	group = bmain->group.first;
-	while (group) {
-		BKE_group_object_unlink(group, ob, NULL, NULL);
-		group = group->id.next;
-	}
-	
-	/* cameras */
-	camera = bmain->camera.first;
-	while (camera) {
-		if (camera->dof_ob == ob) {
-			camera->dof_ob = NULL;
-		}
-		camera = camera->id.next;
-	}
-}
-
 /* actual check for internal data, not context or flags */
 bool BKE_object_is_in_editmode(Object *ob)
 {