Refactor: Remove `BKE_XXX_localize()`, in favor of using regular ID copying code.

Besides the NodeTree case (which remains unchanged), the localize code
is only used in one place (to generate previews of shading data-blocks).

This commit introduces a new `LIB_ID_CREATE_LOCAL` option for ID
creation/copying, which essentially implements the behavior of the
removed `BKE_XXX_localize()` functions into regular mainstream ID copy
code. When this option is set:
- new ID is tagged with `LIB_TAG_LOCALIZED`;
- Some ID copying callbacks have specific behaviors, mainly the root
  nodetree of shading IDs gets duplicated with specialized
  `ntreeLocalize()` function.

Note that I would not consider getting rid of `ntreeLocalize` for now,
this function is recursive, which should ideally never happen within ID
management copying code (this introduces all kind of complications).

No behavioral change expected from this commit.

11 files changed, 67 insertions, 145 deletions

diff --git a/source/blender/blenkernel/BKE_lib_id.h b/source/blender/blenkernel/BKE_lib_id.h
index c3c4c228b61..33ccd20bcff 100644
--- a/source/blender/blenkernel/BKE_lib_id.h
+++ b/source/blender/blenkernel/BKE_lib_id.h
@@ -99,6 +99,12 @@ enum {
   /** Do not tag new ID for update in depsgraph. */
   LIB_ID_CREATE_NO_DEG_TAG = 1 << 8,
 
+  /** Very similar to #LIB_ID_CREATE_NO_MAIN, and should never be used with it (typically combined
+   * with #LIB_ID_CREATE_LOCALIZE or #LIB_ID_COPY_LOCALIZE in fact).
+   * It ensures that IDs created with it will get the #LIB_TAG_LOCALIZED tag, and uses some
+   * specific code in some copy cases (mostly for node trees). */
+  LIB_ID_CREATE_LOCAL = 1 << 9,
+
   /* *** Specific options to some ID types or usages. *** */
   /* *** May be ignored by unrelated ID copying functions. *** */
   /** Object only, needed by make_local code. */
diff --git a/source/blender/blenkernel/BKE_light.h b/source/blender/blenkernel/BKE_light.h
index 026e5d1a13b..9a619f0a0fa 100644
--- a/source/blender/blenkernel/BKE_light.h
+++ b/source/blender/blenkernel/BKE_light.h
@@ -36,7 +36,6 @@ struct Main;
 
 struct Light *BKE_light_add(struct Main *bmain, const char *name) ATTR_WARN_UNUSED_RESULT;
 struct Light *BKE_light_copy(struct Main *bmain, const struct Light *la) ATTR_WARN_UNUSED_RESULT;
-struct Light *BKE_light_localize(struct Light *la) ATTR_WARN_UNUSED_RESULT;
 
 void BKE_light_eval(struct Depsgraph *depsgraph, struct Light *la);
 
diff --git a/source/blender/blenkernel/BKE_material.h b/source/blender/blenkernel/BKE_material.h
index a6d8d2d2d8b..aeb7600d647 100644
--- a/source/blender/blenkernel/BKE_material.h
+++ b/source/blender/blenkernel/BKE_material.h
@@ -54,7 +54,6 @@ void BKE_object_material_remap_calc(struct Object *ob_dst,
 struct Material *BKE_material_add(struct Main *bmain, const char *name);
 struct Material *BKE_gpencil_material_add(struct Main *bmain, const char *name);
 struct Material *BKE_material_copy(struct Main *bmain, const struct Material *ma);
-struct Material *BKE_material_localize(struct Material *ma);
 void BKE_gpencil_material_attr_init(struct Material *ma);
 
 /* UNUSED */
diff --git a/source/blender/blenkernel/BKE_texture.h b/source/blender/blenkernel/BKE_texture.h
index aae8ffc47b9..47ef0c4c63b 100644
--- a/source/blender/blenkernel/BKE_texture.h
+++ b/source/blender/blenkernel/BKE_texture.h
@@ -47,7 +47,6 @@ void BKE_texture_mtex_foreach_id(struct LibraryForeachIDData *data, struct MTex
 void BKE_texture_default(struct Tex *tex);
 struct Tex *BKE_texture_copy(struct Main *bmain, const struct Tex *tex);
 struct Tex *BKE_texture_add(struct Main *bmain, const char *name);
-struct Tex *BKE_texture_localize(struct Tex *tex);
 void BKE_texture_type_set(struct Tex *tex, int type);
 
 void BKE_texture_mtex_default(struct MTex *mtex);
diff --git a/source/blender/blenkernel/BKE_world.h b/source/blender/blenkernel/BKE_world.h
index 73eb340e887..bbab6fa2712 100644
--- a/source/blender/blenkernel/BKE_world.h
+++ b/source/blender/blenkernel/BKE_world.h
@@ -31,7 +31,6 @@ struct Main;
 struct World;
 
 struct World *BKE_world_add(struct Main *bmain, const char *name);
-struct World *BKE_world_localize(struct World *wrld);
 void BKE_world_eval(struct Depsgraph *depsgraph, struct World *world);
 
 #ifdef __cplusplus
diff --git a/source/blender/blenkernel/intern/lib_id.c b/source/blender/blenkernel/intern/lib_id.c
index 8f3d05ce914..fd127f5871f 100644
--- a/source/blender/blenkernel/intern/lib_id.c
+++ b/source/blender/blenkernel/intern/lib_id.c
@@ -1035,6 +1035,8 @@ void *BKE_libblock_alloc_notest(short type)
 void *BKE_libblock_alloc(Main *bmain, short type, const char *name, const int flag)
 {
   BLI_assert((flag & LIB_ID_CREATE_NO_ALLOCATE) == 0);
+  BLI_assert((flag & LIB_ID_CREATE_NO_MAIN) != 0 || bmain != NULL);
+  BLI_assert((flag & LIB_ID_CREATE_NO_MAIN) != 0 || (flag & LIB_ID_CREATE_LOCAL) == 0);
 
   ID *id = BKE_libblock_alloc_notest(type);
 
@@ -1045,6 +1047,9 @@ void *BKE_libblock_alloc(Main *bmain, short type, const char *name, const int fl
     if ((flag & LIB_ID_CREATE_NO_USER_REFCOUNT) != 0) {
       id->tag |= LIB_TAG_NO_USER_REFCOUNT;
     }
+    if (flag & LIB_ID_CREATE_LOCAL) {
+      id->tag |= LIB_TAG_LOCALIZED;
+    }
 
     id->icon_id = 0;
     *((short *)id->name) = type;
@@ -1180,6 +1185,7 @@ void BKE_libblock_copy_ex(Main *bmain, const ID *id, ID **r_newid, const int ori
 
   BLI_assert((flag & LIB_ID_CREATE_NO_MAIN) != 0 || bmain != NULL);
   BLI_assert((flag & LIB_ID_CREATE_NO_MAIN) != 0 || (flag & LIB_ID_CREATE_NO_ALLOCATE) == 0);
+  BLI_assert((flag & LIB_ID_CREATE_NO_MAIN) != 0 || (flag & LIB_ID_CREATE_LOCAL) == 0);
   if (!is_private_id_data) {
     /* When we are handling private ID data, we might still want to manage usercounts, even
      * though that ID data-block is actually outside of Main... */
diff --git a/source/blender/blenkernel/intern/light.c b/source/blender/blenkernel/intern/light.c
index 1ce079b006e..437e61a5fca 100644
--- a/source/blender/blenkernel/intern/light.c
+++ b/source/blender/blenkernel/intern/light.c
@@ -81,13 +81,21 @@ static void light_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
 {
   Light *la_dst = (Light *)id_dst;
   const Light *la_src = (const Light *)id_src;
+
+  const bool is_localized = (flag & LIB_ID_CREATE_LOCAL) != 0;
   /* We always need allocation of our private ID data. */
   const int flag_private_id_data = flag & ~LIB_ID_CREATE_NO_ALLOCATE;
 
   la_dst->curfalloff = BKE_curvemapping_copy(la_src->curfalloff);
 
   if (la_src->nodetree) {
-    BKE_id_copy_ex(bmain, (ID *)la_src->nodetree, (ID **)&la_dst->nodetree, flag_private_id_data);
+    if (is_localized) {
+      la_dst->nodetree = ntreeLocalize(la_src->nodetree);
+    }
+    else {
+      BKE_id_copy_ex(
+          bmain, (ID *)la_src->nodetree, (ID **)&la_dst->nodetree, flag_private_id_data);
+    }
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -219,33 +227,6 @@ Light *BKE_light_copy(Main *bmain, const Light *la)
   return la_copy;
 }
 
-Light *BKE_light_localize(Light *la)
-{
-  /* TODO(bastien): Replace with something like:
-   *
-   *   Light *la_copy;
-   *   BKE_id_copy_ex(bmain, &la->id, (ID **)&la_copy,
-   *                  LIB_ID_COPY_NO_MAIN | LIB_ID_COPY_NO_PREVIEW | LIB_ID_COPY_NO_USER_REFCOUNT,
-   *                  false);
-   *   return la_copy;
-   *
-   * NOTE: Only possible once nested node trees are fully converted to that too. */
-
-  Light *lan = BKE_libblock_copy_for_localize(&la->id);
-
-  lan->curfalloff = BKE_curvemapping_copy(la->curfalloff);
-
-  if (la->nodetree) {
-    lan->nodetree = ntreeLocalize(la->nodetree);
-  }
-
-  lan->preview = NULL;
-
-  lan->id.tag |= LIB_TAG_LOCALIZED;
-
-  return lan;
-}
-
 void BKE_light_eval(struct Depsgraph *depsgraph, Light *la)
 {
   DEG_debug_print_eval(depsgraph, __func__, la->id.name, la);
diff --git a/source/blender/blenkernel/intern/material.c b/source/blender/blenkernel/intern/material.c
index d8c0b5d6dce..8c09cb551a1 100644
--- a/source/blender/blenkernel/intern/material.c
+++ b/source/blender/blenkernel/intern/material.c
@@ -100,12 +100,20 @@ static void material_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
   Material *material_dst = (Material *)id_dst;
   const Material *material_src = (const Material *)id_src;
 
+  const bool is_localized = (flag & LIB_ID_CREATE_LOCAL) != 0;
   /* We always need allocation of our private ID data. */
   const int flag_private_id_data = flag & ~LIB_ID_CREATE_NO_ALLOCATE;
 
-  if (material_src->nodetree) {
-    BKE_id_copy_ex(
-        bmain, (ID *)material_src->nodetree, (ID **)&material_dst->nodetree, flag_private_id_data);
+  if (material_src->nodetree != NULL) {
+    if (is_localized) {
+      material_dst->nodetree = ntreeLocalize(material_src->nodetree);
+    }
+    else {
+      BKE_id_copy_ex(bmain,
+                     (ID *)material_src->nodetree,
+                     (ID **)&material_dst->nodetree,
+                     flag_private_id_data);
+    }
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -116,7 +124,8 @@ static void material_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const
   }
 
   if (material_src->texpaintslot != NULL) {
-    material_dst->texpaintslot = MEM_dupallocN(material_src->texpaintslot);
+    /* TODO: Think we can also skip copying this data in the more generic `NO_MAIN` case? */
+    material_dst->texpaintslot = is_localized ? NULL : MEM_dupallocN(material_src->texpaintslot);
   }
 
   if (material_src->gp_style != NULL) {
@@ -315,41 +324,6 @@ Material *BKE_material_copy(Main *bmain, const Material *ma)
   return ma_copy;
 }
 
-/* XXX (see above) material copy without adding to main dbase */
-Material *BKE_material_localize(Material *ma)
-{
-  /* TODO(bastien): Replace with something like:
-   *
-   *   Material *ma_copy;
-   *   BKE_id_copy_ex(bmain, &ma->id, (ID **)&ma_copy,
-   *                  LIB_ID_COPY_NO_MAIN | LIB_ID_COPY_NO_PREVIEW | LIB_ID_COPY_NO_USER_REFCOUNT,
-   *                  false);
-   *   return ma_copy;
-   *
-   * NOTE: Only possible once nested node trees are fully converted to that too. */
-
-  Material *man = BKE_libblock_copy_for_localize(&ma->id);
-
-  man->texpaintslot = NULL;
-  man->preview = NULL;
-
-  if (ma->nodetree != NULL) {
-    man->nodetree = ntreeLocalize(ma->nodetree);
-  }
-
-  if (ma->gp_style != NULL) {
-    man->gp_style = MEM_dupallocN(ma->gp_style);
-  }
-
-  BLI_listbase_clear(&man->gpumaterial);
-
-  /* TODO Duplicate Engine Settings and set runtime to NULL */
-
-  man->id.tag |= LIB_TAG_LOCALIZED;
-
-  return man;
-}
-
 Material ***BKE_object_material_array_p(Object *ob)
 {
   if (ob->type == OB_MESH) {
diff --git a/source/blender/blenkernel/intern/texture.c b/source/blender/blenkernel/intern/texture.c
index b74b7d57b2e..4d113597745 100644
--- a/source/blender/blenkernel/intern/texture.c
+++ b/source/blender/blenkernel/intern/texture.c
@@ -87,6 +87,7 @@ static void texture_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const i
   Tex *texture_dst = (Tex *)id_dst;
   const Tex *texture_src = (const Tex *)id_src;
 
+  const bool is_localized = (flag & LIB_ID_CREATE_LOCAL) != 0;
   /* We always need allocation of our private ID data. */
   const int flag_private_id_data = flag & ~LIB_ID_CREATE_NO_ALLOCATE;
 
@@ -101,8 +102,14 @@ static void texture_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const i
     if (texture_src->nodetree->execdata) {
       ntreeTexEndExecTree(texture_src->nodetree->execdata);
     }
-    BKE_id_copy_ex(
-        bmain, (ID *)texture_src->nodetree, (ID **)&texture_dst->nodetree, flag_private_id_data);
+
+    if (is_localized) {
+      texture_dst->nodetree = ntreeLocalize(texture_src->nodetree);
+    }
+    else {
+      BKE_id_copy_ex(
+          bmain, (ID *)texture_src->nodetree, (ID **)&texture_dst->nodetree, flag_private_id_data);
+    }
   }
 
   if ((flag & LIB_ID_COPY_NO_PREVIEW) == 0) {
@@ -455,40 +462,6 @@ Tex *BKE_texture_copy(Main *bmain, const Tex *tex)
   return tex_copy;
 }
 
-/* texture copy without adding to main dbase */
-Tex *BKE_texture_localize(Tex *tex)
-{
-  /* TODO(bastien): Replace with something like:
-   *
-   *   Tex *tex_copy;
-   *   BKE_id_copy_ex(bmain, &tex->id, (ID **)&tex_copy,
-   *                  LIB_ID_COPY_NO_MAIN | LIB_ID_COPY_NO_PREVIEW | LIB_ID_COPY_NO_USER_REFCOUNT,
-   *                  false);
-   *   return tex_copy;
-   *
-   * NOTE: Only possible once nested node trees are fully converted to that too. */
-
-  Tex *texn;
-
-  texn = BKE_libblock_copy_for_localize(&tex->id);
-
-  /* image texture: texture_free_data also doesn't decrease */
-
-  if (texn->coba) {
-    texn->coba = MEM_dupallocN(texn->coba);
-  }
-
-  texn->preview = NULL;
-
-  if (tex->nodetree) {
-    texn->nodetree = ntreeLocalize(tex->nodetree);
-  }
-
-  texn->id.tag |= LIB_TAG_LOCALIZED;
-
-  return texn;
-}
-
 /* ------------------------------------------------------------------------- */
 
 Tex *give_current_linestyle_texture(FreestyleLineStyle *linestyle)
diff --git a/source/blender/blenkernel/intern/world.c b/source/blender/blenkernel/intern/world.c
index d5142e2d1a4..7590afeaaff 100644
--- a/source/blender/blenkernel/intern/world.c
+++ b/source/blender/blenkernel/intern/world.c
@@ -99,12 +99,19 @@ static void world_copy_data(Main *bmain, ID *id_dst, const ID *id_src, const int
 {
   World *wrld_dst = (World *)id_dst;
   const World *wrld_src = (const World *)id_src;
+
+  const bool is_localized = (flag & LIB_ID_CREATE_LOCAL) != 0;
   /* We always need allocation of our private ID data. */
   const int flag_private_id_data = flag & ~LIB_ID_CREATE_NO_ALLOCATE;
 
   if (wrld_src->nodetree) {
-    BKE_id_copy_ex(
-        bmain, (ID *)wrld_src->nodetree, (ID **)&wrld_dst->nodetree, flag_private_id_data);
+    if (is_localized) {
+      wrld_dst->nodetree = ntreeLocalize(wrld_src->nodetree);
+    }
+    else {
+      BKE_id_copy_ex(
+          bmain, (ID *)wrld_src->nodetree, (ID **)&wrld_dst->nodetree, flag_private_id_data);
+    }
   }
 
   BLI_listbase_clear(&wrld_dst->gpumaterial);
@@ -210,36 +217,6 @@ World *BKE_world_add(Main *bmain, const char *name)
   return wrld;
 }
 
-World *BKE_world_localize(World *wrld)
-{
-  /* TODO(bastien): Replace with something like:
-   *
-   *   World *wrld_copy;
-   *   BKE_id_copy_ex(bmain, &wrld->id, (ID **)&wrld_copy,
-   *                  LIB_ID_COPY_NO_MAIN | LIB_ID_COPY_NO_PREVIEW | LIB_ID_COPY_NO_USER_REFCOUNT,
-   *                  false);
-   *   return wrld_copy;
-   *
-   * NOTE: Only possible once nested node trees are fully converted to that too. */
-
-  World *wrldn;
-
-  wrldn = BKE_libblock_copy_for_localize(&wrld->id);
-
-  if (wrld->nodetree) {
-    wrldn->nodetree = ntreeLocalize(wrld->nodetree);
-  }
-
-  wrldn->preview = NULL;
-
-  BLI_listbase_clear(&wrldn->gpumaterial);
-  BLI_listbase_clear((ListBase *)&wrldn->drawdata);
-
-  wrldn->id.tag |= LIB_TAG_LOCALIZED;
-
-  return wrldn;
-}
-
 void BKE_world_eval(struct Depsgraph *depsgraph, World *world)
 {
   DEG_debug_print_eval(depsgraph, __func__, world->id.name, world);
diff --git a/source/blender/editors/render/render_preview.c b/source/blender/editors/render/render_preview.c
index 4a4f6127851..d7eaaf3277b 100644
--- a/source/blender/editors/render/render_preview.c
+++ b/source/blender/editors/render/render_preview.c
@@ -325,7 +325,13 @@ static World *preview_get_localized_world(ShaderPreview *sp, World *world)
   if (sp->worldcopy != NULL) {
     return sp->worldcopy;
   }
-  sp->worldcopy = BKE_world_localize(world);
+
+  ID *id_copy;
+  BKE_id_copy_ex(NULL,
+                 &world->id,
+                 &id_copy,
+                 LIB_ID_CREATE_LOCAL | LIB_ID_COPY_LOCALIZE | LIB_ID_COPY_NO_ANIMDATA);
+  sp->worldcopy = (World *)id_copy;
   BLI_addtail(&sp->pr_main->worlds, sp->worldcopy);
   return sp->worldcopy;
 }
@@ -339,13 +345,16 @@ static ID *duplicate_ids(ID *id)
 
   switch (GS(id->name)) {
     case ID_MA:
-      return (ID *)BKE_material_localize((Material *)id);
     case ID_TE:
-      return (ID *)BKE_texture_localize((Tex *)id);
     case ID_LA:
-      return (ID *)BKE_light_localize((Light *)id);
-    case ID_WO:
-      return (ID *)BKE_world_localize((World *)id);
+    case ID_WO: {
+      ID *id_copy;
+      BKE_id_copy_ex(NULL,
+                     id,
+                     &id_copy,
+                     LIB_ID_CREATE_LOCAL | LIB_ID_COPY_LOCALIZE | LIB_ID_COPY_NO_ANIMDATA);
+      return id_copy;
+    }
     case ID_IM:
     case ID_BR:
     case ID_SCR: