Add helper to BKE_library to generate unique string key for an ID.

Basically just concatenates ID's name (including its IDtype code) and
that library's name, if any. This must give unique string in a given
Main database, suitable for GHash keys e.g.

1 files changed, 19 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/library.c b/source/blender/blenkernel/intern/library.c
index 08d68f4a480..06207eabe31 100644
--- a/source/blender/blenkernel/intern/library.c
+++ b/source/blender/blenkernel/intern/library.c
@@ -2535,6 +2535,25 @@ void BKE_id_ui_prefix(char name[MAX_ID_NAME + 1], const ID *id)
 	strcpy(name + 3, id->name + 2);
 }
 
+/**
+ * Returns an allocated string concatenating ID name (including two-chars type code) and its lib name if any,
+ * which is expected to be unique in a given Main database..
+ */
+char *BKE_id_to_unique_string_key(const struct ID *id)
+{
+	const size_t key_len_base = strlen(id->name) + 1;
+	const size_t key_len_ext = ((id->lib != NULL) ? strlen(id->lib->name) : 0) + 1;
+	const size_t key_len = key_len_base + key_len_ext - 1;
+	char *key = MEM_mallocN(key_len, __func__);
+
+	BLI_strncpy(key, id->name, key_len_base);
+	if (id->lib != NULL) {
+		BLI_strncpy(key + key_len_base - 1, id->lib->name, key_len_ext);
+	}
+
+	return key;
+}
+
 void BKE_library_filepath_set(Main *bmain, Library *lib, const char *filepath)
 {
 	/* in some cases this is used to update the absolute path from the