[epiphany] ephy-embed: slightly delay delayed load requests

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 6863df9a1027cf506af09a1ce13b53b10f20c858
Author: Michael Catanzaro <mcatanzaro igalia com>
Date:   Thu Feb 26 21:18:33 2015 -0600

    ephy-embed: slightly delay delayed load requests
    
    If the user is rapidly switching through many tabs with delayed load
    requests, we shouldn't load them all. Instead, wait until the user stops
    briefly on a tab before loading it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745260

 embed/ephy-embed.c |   36 +++++++++++++++++++++++++++++++-----
 1 files changed, 31 insertions(+), 5 deletions(-)
---
diff --git a/embed/ephy-embed.c b/embed/ephy-embed.c
index 798bbc4..a98824a 100644
--- a/embed/ephy-embed.c
+++ b/embed/ephy-embed.c
@@ -70,6 +70,7 @@ struct _EphyEmbedPrivate
 
   char *title;
   WebKitURIRequest *delayed_request;
+  guint delayed_request_source_id;
 
   GSList *messages;
   GSList *keys;
@@ -365,6 +366,11 @@ ephy_embed_dispose (GObject *object)
     priv->clear_progress_source_id = 0;
   }
 
+  if (priv->delayed_request_source_id) {
+    g_source_remove (priv->delayed_request_source_id);
+    priv->delayed_request_source_id = 0;
+  }
+
   /* Do not listen to status message notifications anymore, if we try
    * to update the statusbar after dispose we might crash. */
   if (priv->status_handler_id) {
@@ -648,17 +654,19 @@ progress_update (EphyWebView *view, GParamSpec *pspec, EphyEmbed *embed)
                                  (loading || progress == 1.0) ? progress : 0.0);
 }
 
-static void
-ephy_embed_maybe_load_delayed_request (EphyEmbed *embed)
+static gboolean
+load_delayed_request_if_mapped (gpointer user_data)
 {
+  EphyEmbed *embed = EPHY_EMBED (user_data);
   EphyEmbedPrivate *priv = embed->priv;
   EphyWebView *web_view;
 
-  if (!priv->delayed_request)
-    return;
+  priv->delayed_request_source_id = 0;
 
-  web_view = ephy_embed_get_web_view (embed);
+  if (!gtk_widget_get_mapped (GTK_WIDGET (embed)))
+    return G_SOURCE_REMOVE;
 
+  web_view = ephy_embed_get_web_view (embed);
   ephy_web_view_load_request (web_view, priv->delayed_request);
   g_clear_object (&priv->delayed_request);
 
@@ -666,6 +674,24 @@ ephy_embed_maybe_load_delayed_request (EphyEmbed *embed)
    * loading as soon as possible.
    */
   g_signal_emit_by_name (web_view, "load-changed", WEBKIT_LOAD_STARTED);
+
+  return G_SOURCE_REMOVE;
+}
+
+static void
+ephy_embed_maybe_load_delayed_request (EphyEmbed *embed)
+{
+  EphyEmbedPrivate *priv = embed->priv;
+
+  if (!priv->delayed_request || priv->delayed_request_source_id != 0)
+    return;
+
+  /* Add a very small delay before loading the request, so that if the user
+   * is scrolling rapidly through a bunch of delayed tabs, we don't start
+   * loading them all.
+   */
+  priv->delayed_request_source_id = g_timeout_add (300, load_delayed_request_if_mapped, embed);
+  g_source_set_name_by_id (priv->delayed_request_source_id, "[epiphany] load_delayed_request_if_mapped");
 }
 
 static void