[PATCH 07/15] core: Free specs after last element is sent

["Juan A. Suarez Romero" <jasuarez igalia com>]

So far, specs were inmediatly destroyed when sources invoke callback with
remaining == 0.

This has the drawback that after it, spec is no longer valid, and sources
should avoid to use them. This means that sources must copy spec content if
they want to use them after the callback.

To avoid this problem, add an idle function to free the spec after source
invokes callback with remaining == 0. So source is safe to continue accessing
the spec content, and when it returns, the idle function to free the spec will
be activated.

Even more, if source, for any reason, needs to keep the spec even after
returning (could be the spec is in turn wrapped in another structure handled in
an idle function), it can ref() the spec, so it is not destroyed in the return,
but later, when source calls the appropriate unref() function.
---
 src/grl-media-source.c |  151 ++++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 128 insertions(+), 23 deletions(-)

diff --git a/src/grl-media-source.c b/src/grl-media-source.c
index 19508f6..c94552c 100644
--- a/src/grl-media-source.c
+++ b/src/grl-media-source.c
@@ -140,6 +140,18 @@ struct MetadataRelayCb {
   GrlMediaSourceMetadataSpec *spec;
 };
 
+struct StoreRelayCb {
+  GrlMediaSourceStoreCb user_callback;
+  gpointer user_data;
+  GrlMediaSourceStoreSpec *spec;
+};
+
+struct RemoveRelayCb {
+  GrlMediaSourceRemoveCb user_callback;
+  gpointer user_data;
+  GrlMediaSourceRemoveSpec *spec;
+};
+
 struct OperationState {
   gboolean cancelled;
   gboolean completed;
@@ -575,6 +587,65 @@ auto_split_run_next_chunk (struct BrowseRelayCb *brc, guint remaining)
   g_idle_add (operation, spec);
 }
 
+static gboolean
+browse_relay_free (gpointer user_data)
+{
+  struct BrowseRelayCb *brc = (struct BrowseRelayCb *) user_data;
+
+  g_debug ("browse_relay_free");
+
+  if (brc->bspec) {
+    grl_media_source_browse_spec_unref (brc->bspec);
+  } else if (brc->sspec) {
+    grl_media_source_search_spec_unref (brc->sspec);
+  } else if (brc->sspec) {
+    grl_media_source_query_spec_unref (brc->qspec);
+  }
+  g_free (brc->auto_split);
+  g_free (brc);
+
+  return FALSE;
+}
+
+static gboolean
+metadata_relay_free (gpointer user_data)
+{
+  struct MetadataRelayCb *mrc = (struct MetadataRelayCb *) user_data;
+
+  g_debug ("metadata_relay_free");
+
+  grl_media_source_metadata_spec_unref (mrc->spec);
+  g_free (mrc);
+
+  return FALSE;
+}
+
+static gboolean
+store_relay_free (gpointer user_data)
+{
+  struct StoreRelayCb *src = (struct StoreRelayCb *) user_data;
+
+  g_debug ("store_relay_free");
+
+  grl_media_source_store_spec_unref (src->spec);
+  g_free (src);
+
+  return FALSE;
+}
+
+static gboolean
+remove_relay_free (gpointer user_data)
+{
+  struct RemoveRelayCb *rrc = (struct RemoveRelayCb *) user_data;
+
+  g_debug ("remove_relay_free");
+
+  grl_media_source_remove_spec_unref (rrc->spec);
+  g_free (rrc);
+
+  return FALSE;
+}
+
 static void
 browse_result_relay_cb (GrlMediaSource *source,
 			guint browse_id,
@@ -703,15 +774,7 @@ browse_result_relay_cb (GrlMediaSource *source,
   if (remaining == 0) {
     g_debug ("Got remaining '0' for operation %d (%s)",
 	     browse_id,  grl_metadata_source_get_name (GRL_METADATA_SOURCE (source)));
-    if (brc->bspec) {
-      grl_media_source_browse_spec_unref (brc->bspec);
-    } else if (brc->sspec) {
-      grl_media_source_search_spec_unref (brc->sspec);
-    } else if (brc->sspec) {
-      grl_media_source_query_spec_unref (brc->qspec);
-    }
-    g_free (brc->auto_split);
-    g_free (brc);
+    g_idle_add (browse_relay_free, brc);
   }
 }
 
@@ -767,8 +830,7 @@ metadata_result_relay_cb (GrlMediaSource *source,
 
   mrc->user_callback (source, media, mrc->user_data, error);
 
-  grl_media_source_metadata_spec_unref (mrc->spec);
-  g_free (mrc);
+  g_idle_add (metadata_relay_free, mrc);
 }
 
 static void
@@ -790,6 +852,24 @@ metadata_result_async_cb (GrlMediaSource *source,
 }
 
 static void
+store_result_relay_cb (GrlMediaSource *source,
+                       GrlMediaBox *parent,
+                       GrlMedia *media,
+                       gpointer user_data,
+                       const GError *error)
+{
+  g_debug ("store_result_relay_cb");
+
+  struct StoreRelayCb *src;
+
+  src = (struct StoreRelayCb *) user_data;
+
+  src->user_callback (source, parent, media, src->user_data, error);
+
+  g_idle_add (store_relay_free, src);
+}
+
+static void
 store_async_cb (GrlMediaSource *source,
                 GrlMediaBox *parent,
                 GrlMedia *media,
@@ -808,6 +888,23 @@ store_async_cb (GrlMediaSource *source,
 }
 
 static void
+remove_result_relay_cb (GrlMediaSource *source,
+                        GrlMedia *media,
+                        gpointer user_data,
+                        const GError *error)
+{
+  g_debug ("remove_result_relay_cb");
+
+  struct RemoveRelayCb *rrc;
+
+  rrc = (struct RemoveRelayCb *) user_data;
+
+  rrc->user_callback (source, media, rrc->user_data, error);
+
+  g_idle_add (remove_relay_free, rrc);
+}
+
+static void
 remove_async_cb (GrlMediaSource *source,
                  GrlMedia *media,
                  gpointer user_data,
@@ -2253,6 +2350,7 @@ grl_media_source_store (GrlMediaSource *source,
 
   const gchar *title;
   const gchar *url;
+  struct StoreRelayCb *src;
   GError *error = NULL;
   GrlMediaSourceStoreSpec *ss;
 
@@ -2283,17 +2381,20 @@ grl_media_source_store (GrlMediaSource *source,
 
   /* If we have the info, ask the plugin to store the media */
   if (!error) {
+    src = g_new (struct StoreRelayCb, 1);
+    src->user_callback = callback;
+    src->user_data = user_data;
+
     ss = grl_media_source_store_spec_new ();
     ss->source = g_object_ref (source);
     ss->parent = parent ? g_object_ref (parent) : NULL;
     ss->media = g_object_ref (media);
-    ss->callback = callback;
-    ss->user_data = user_data;
+    ss->callback = store_result_relay_cb;
+    ss->user_data = src;
+
+    src->spec = ss;
 
-    g_idle_add_full (G_PRIORITY_DEFAULT_IDLE,
-		     store_idle,
-		     ss,
-                     (GDestroyNotify) grl_media_source_store_spec_unref);
+    g_idle_add (store_idle, ss);
   } else {
     callback (source, parent, media, user_data, error);
     g_error_free (error);
@@ -2360,6 +2461,7 @@ grl_media_source_remove (GrlMediaSource *source,
   g_debug ("grl_media_source_remove");
 
   const gchar *id;
+  struct RemoveRelayCb *rrc;
   GError *error = NULL;
   GrlMediaSourceRemoveSpec *rs;
 
@@ -2378,17 +2480,20 @@ grl_media_source_remove (GrlMediaSource *source,
   }
 
   if (!error) {
+    rrc = g_new (struct RemoveRelayCb, 1);
+    rrc->user_callback = callback;
+    rrc->user_data = user_data;
+
     rs = grl_media_source_remove_spec_new ();
     rs->source = g_object_ref (source);
     rs->media_id = g_strdup (id);
     rs->media = g_object_ref (media);
-    rs->callback = callback;
-    rs->user_data = user_data;
+    rs->callback = remove_result_relay_cb;
+    rs->user_data = rrc;
+
+    rrc->spec = rs;
 
-    g_idle_add_full (G_PRIORITY_DEFAULT_IDLE,
-		     remove_idle,
-		     rs,
-                     (GDestroyNotify) grl_media_source_remove_spec_unref);
+    g_idle_add (remove_idle, rs);
   } else {
     callback (source, media, user_data, error);
     g_error_free (error);
-- 
1.7.0.4