Make sdl_surface:img_load/1 run in the main thread

While this and other surface functions don't need to, depending
on the backend or flags the surface may not be in system memory
and therefore may not be thread safe.

2 files changed, 24 insertions, 5 deletions

diff --git a/c_src/sdl_surface.c b/c_src/sdl_surface.c
index 6f43f3e..97c755a 100644
--- a/c_src/sdl_surface.c
+++ b/c_src/sdl_surface.c
@@ -20,15 +20,17 @@ void dtor_Surface(ErlNifEnv* env, void* obj)
 	SDL_FreeSurface(NIF_RES_GET(Surface, obj));
 }
 
-NIF_FUNCTION(img_load)
+// img_load
+
+NIF_CALL_HANDLER(thread_img_load)
 {
-	char filename[FILENAME_MAX];
 	SDL_Surface* surface;
 	ERL_NIF_TERM term;
 
-	BADARG_IF(!enif_get_string(env, argv[0], filename, FILENAME_MAX, ERL_NIF_LATIN1));
+	surface = IMG_Load(args[0]);
+
+	enif_free(args[0]);
 
-	surface = IMG_Load(filename);
 	if (!surface)
 		return sdl_error_tuple(env);
 
@@ -39,3 +41,19 @@ NIF_FUNCTION(img_load)
 		term
 	);
 }
+
+NIF_FUNCTION(img_load)
+{
+	unsigned int len;
+	char *filename;
+
+	BADARG_IF(!enif_get_list_length(env, argv[0], &len));
+	filename = (char*)enif_alloc(len + 1);
+
+	if (!enif_get_string(env, argv[0], filename, len + 1, ERL_NIF_LATIN1)) {
+		enif_free(filename);
+		return enif_make_badarg(env);
+	}
+
+	return nif_thread_call(env, thread_img_load, 1, filename);
+}
diff --git a/src/sdl_surface.erl b/src/sdl_surface.erl
index f36407f..15a4dec 100644
--- a/src/sdl_surface.erl
+++ b/src/sdl_surface.erl
@@ -17,4 +17,5 @@
 -export([load/1]).
 
 load(Filename) ->
-	esdl2:img_load(Filename).
+	esdl2:img_load(Filename),
+	receive {'_nif_thread_ret_', Ret} -> Ret end.