[grilo-plugins] lua-factory: Protect against broken sources

[Bastien Nocera <hadess src gnome org>]

commit 3ceffa5fbdb974769ba6f6fa47183bef64ea7396
Author: Bastien Nocera <hadess hadess net>
Date:   Tue Mar 18 10:47:10 2014 +0100

    lua-factory: Protect against broken sources
    
    If no fetches are pending and grl.callback() was not called,
    throw a warning, and clean up after the source to avoid
    inconsistent states in front-ends.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=725209

 src/lua-factory/grl-lua-common.h  |    2 ++
 src/lua-factory/grl-lua-library.c |   24 ++++++++++++++++++++++++
 2 files changed, 26 insertions(+), 0 deletions(-)
---
diff --git a/src/lua-factory/grl-lua-common.h b/src/lua-factory/grl-lua-common.h
index 8ed1c57..e951b94 100644
--- a/src/lua-factory/grl-lua-common.h
+++ b/src/lua-factory/grl-lua-common.h
@@ -64,6 +64,8 @@ typedef struct _OperationSpec {
   GrlMedia *media;
   gpointer user_data;
   guint error_code;
+  guint pending_ops;
+  gboolean callback_done;
 } OperationSpec;
 
 void grl_lua_library_save_operation_data (lua_State *L, OperationSpec *os);
diff --git a/src/lua-factory/grl-lua-library.c b/src/lua-factory/grl-lua-library.c
index a47eb85..943ccc4 100644
--- a/src/lua-factory/grl-lua-library.c
+++ b/src/lua-factory/grl-lua-library.c
@@ -303,6 +303,7 @@ grl_util_fetch_done (GObject *source_object,
   gchar *data = NULL;
   guint i = 0;
   GError *err = NULL;
+  OperationSpec *os;
   FetchOperation *fo = (FetchOperation *) user_data;
   lua_State *L = fo->L;
 
@@ -329,6 +330,8 @@ grl_util_fetch_done (GObject *source_object,
   }
 
   grl_lua_library_set_current_operation (L, fo->operation_id);
+  os = grl_lua_library_get_current_operation (L);
+  os->pending_ops--;
 
   lua_getglobal (L, fo->lua_cb);
 
@@ -607,6 +610,7 @@ grl_l_fetch (lua_State *L)
 
   os = grl_lua_library_get_current_operation (L);
   g_return_val_if_fail (os != NULL, 0);
+  os->pending_ops++;
 
   num_urls = (lua_isstring (L, 1)) ? 1 : luaL_len (L, 1);
   urls = g_new0 (gchar *, num_urls);
@@ -728,6 +732,7 @@ grl_l_callback (lua_State *L)
   if (count == 0) {
     g_list_free (os->keys);
     g_object_unref (os->options);
+    os->callback_done = TRUE;
     grl_lua_library_remove_operation_data (L, os->operation_id);
     g_slice_free (OperationSpec, os);
   }
@@ -972,6 +977,25 @@ grl_lua_library_set_current_operation (lua_State *L, guint operation_id)
 {
   OperationSpec *os;
 
+  /* Verify that either grl.callback was called, or that there
+   * are pending operations */
+  os = grl_lua_library_get_current_operation (L);
+  if (os) {
+    if (os->pending_ops == 0 && !os->callback_done) {
+      g_warning ("Source '%s' is broken, as there are no pending operations "
+                 "and grl.callback() was not called", grl_source_get_id (os->source));
+      switch (os->op_type) {
+      case LUA_RESOLVE:
+        os->cb.resolve (os->source, os->operation_id, NULL, os->user_data, NULL);
+        break;
+
+      default:
+        os->cb.result (os->source, os->operation_id, NULL,
+                       0, os->user_data, NULL);
+      }
+    }
+  }
+
   if (operation_id > 0)
     os = grl_lua_library_load_operation_data (L, operation_id);
   else