Merge lp:~gue5t/midori/icon-pixbuf into lp:midori

[gue5t gue5t]

Fix segfaults and type errors introduced in r7105 by incorrect downcasts from GIcon to GdkPixbuf in midori-view.c

Fix segfaults and type errors introduced in r7105 by incorrect downcasts from GIcon to GdkPixbuf in midori-view.c

Specifically, midori-view.c was downcasting a GIcon (which is an interface implemented by both GdkPixbuf and GThemedIcon) to a GdkPixbuf in several places where it isn't always true that the icon actually is a GdkPixbuf—for example, there's no pixbuf underlying GThemedIcons. This led to GObject cast failures and segfaults.

This adds code that explicitly converts GThemedIcon instances to GdkPixbufs to allow storing them in the GdkPixbuf* icon field of MidoriView. I've checked it against GTK2/GTK3 to make sure our scaling behavior for icons is unchanged and checked that extensions work without crashes again.

[Paweł Forysiuk (tuxator)]

review: Approve

=== modified file 'midori/midori-view.c'
--- midori/midori-view.c	2016-02-20 17:48:39 +0000
+++ midori/midori-view.c	2016-03-01 20:59:33 +0000
@@ -396,6 +396,14 @@
     katze_item_set_name (view->item, view->title);
 }
 
+/**
+ * midori_view_apply_icon
+ * @view: a #MidoriView
+ * @icon: (transfer none): the icon to apply, either a #GThemedIcon or a #GdkPixbuf
+ * @icon_name: a string corresponding to the icon to apply, or %NULL.
+ *
+ * Obtains a #GdkPixbuf from the given #GIcon and sets it as @view's icon.
+ */
 static void
 midori_view_apply_icon (MidoriView*  view,
                         GIcon*       icon,
@@ -403,8 +411,57 @@
 {
     g_return_if_fail (icon != NULL);
 
+    GdkPixbuf* pixbuf = NULL;
+
+    /* If the GIcon is a GdkPixbuf (since GdkPixbuf implements the GIcon interface), just use it */
+    if (GDK_IS_PIXBUF (icon))
+    {
+        pixbuf = g_object_ref (GDK_PIXBUF (icon));
+    }
+    else if (G_IS_THEMED_ICON (icon)) /* The icon is a GThemedIcon; we must use a GtkIconTheme to render it */
+    {
+        GtkIconTheme* icon_theme;
+        GtkIconInfo* icon_info;
+        gchar** icon_names = NULL;
+        GError* error = NULL;
+
+        icon_theme = gtk_icon_theme_get_for_screen (gtk_widget_get_screen (GTK_WIDGET (view)));
+        g_object_get (icon, "names", &icon_names, NULL);
+
+        icon_info = 
+#if GTK_CHECK_VERSION (3, 0, 0)
+        gtk_icon_theme_choose_icon_for_scale (
+#else
+        gtk_icon_theme_choose_icon (
+#endif
+            icon_theme,
+            (const char **)icon_names,
+            16, /* Favicon-sized */
+#if GTK_CHECK_VERSION (3, 0, 0)
+            gtk_widget_get_scale_factor (GTK_WIDGET (view)),
+#endif
+            0);
+
+        pixbuf = gtk_icon_info_load_icon (icon_info, &error);
+        g_strfreev (icon_names);
+        if (pixbuf == NULL) {
+            g_warning ("Could not load pixbuf for icon '%s': %s\n", icon_name, error->message);
+            g_clear_error (&error);
+
+            /* view->icon cannot be set to NULL, so we simply leave it as-is */
+            return;
+        }
+
+        gtk_icon_info_free (icon_info);
+    }
+    else /* The icon is some other implementation of the GIcon interface, which should be impossible
+    since this is internal API and its only callers pass GdkPixbufs or GThemedIcons */
+    {
+        g_warning ("Could not load pixbuf for icon '%s': unknown GIcon implementation", icon_name);
+    }
+
     katze_item_set_icon (view->item, icon_name);
-    katze_object_assign (view->icon, g_object_ref (icon));
+    katze_object_assign (view->icon, pixbuf);
     g_object_notify (G_OBJECT (view), "icon");
 
     if (view->menu_item)
@@ -414,6 +471,8 @@
     }
 }
 
+/* Resets the view's icon from a WebKit-provided pixbuf for a certain page to a
+generic filetype-based icon */
 static void
 midori_view_unset_icon (MidoriView* view)
 {
@@ -432,6 +491,7 @@
     midori_view_apply_icon (view, icon, NULL);
 }
 
+/* Sets the view's icon pixbuf to the one WebKit provides for the current page */
 static void
 _midori_web_view_load_icon (MidoriView* view)
 {