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, 19 insertions, 9 deletions

diff --git a/source/blender/blenkernel/intern/cachefile.c b/source/blender/blenkernel/intern/cachefile.c
index cf619a32783..1916531b066 100644
--- a/source/blender/blenkernel/intern/cachefile.c
+++ b/source/blender/blenkernel/intern/cachefile.c
@@ -66,7 +66,7 @@ void BKE_cachefiles_exit(void)
 
 void *BKE_cachefile_add(Main *bmain, const char *name)
 {
-	CacheFile *cache_file = BKE_libblock_alloc(bmain, ID_CF, name);
+	CacheFile *cache_file = BKE_libblock_alloc(bmain, ID_CF, name, 0);
 
 	BKE_cachefile_init(cache_file);
 
@@ -100,16 +100,26 @@ void BKE_cachefile_free(CacheFile *cache_file)
 	BLI_freelistN(&cache_file->object_paths);
 }
 
-CacheFile *BKE_cachefile_copy(Main *bmain, const CacheFile *cache_file)
+/**
+ * Only copy internal data of CacheFile 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_cachefile_copy_data(
+        Main *UNUSED(bmain), CacheFile *cache_file_dst, const CacheFile *UNUSED(cache_file_src), const int UNUSED(flag))
 {
-	CacheFile *new_cache_file = BKE_libblock_copy(bmain, &cache_file->id);
-	new_cache_file->handle = NULL;
-
-	BLI_listbase_clear(&new_cache_file->object_paths);
-
-	BKE_id_copy_ensure_local(bmain, &cache_file->id, &new_cache_file->id);
+	cache_file_dst->handle = NULL;
+	BLI_listbase_clear(&cache_file_dst->object_paths);
+}
 
-	return new_cache_file;
+CacheFile *BKE_cachefile_copy(Main *bmain, const CacheFile *cache_file)
+{
+	CacheFile *cache_file_copy;
+	BKE_id_copy_ex(bmain, &cache_file->id, (ID **)&cache_file_copy, 0, false);
+	return cache_file_copy;
 }
 
 void BKE_cachefile_make_local(Main *bmain, CacheFile *cache_file, const bool lib_local)