Add OwnedWidgetGtk, and abstraction to help manage the lifetime and ownership of a GtkWidget encapsulated (and exposed) from a C++ object.

Debugging checks help verify that the GtkWidget is not leaked, and that it was destroyed when expected.

Review URL: http://codereview.chromium.org/42226


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@11740 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 40 insertions, 0 deletions

diff --git a/chrome/common/owned_widget_gtk.cc b/chrome/common/owned_widget_gtk.cc
new file mode 100644
index 0000000..846cd1e
--- /dev/null
+++ b/chrome/common/owned_widget_gtk.cc
@@ -0,0 +1,40 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/common/owned_widget_gtk.h"
+
+#include <gtk/gtk.h>
+
+#include "base/logging.h"
+
+OwnedWidgetGtk::~OwnedWidgetGtk() {
+  DCHECK(!widget_) << "You must explicitly call OwnerWidgetGtk::Destroy().";
+}
+
+void OwnedWidgetGtk::Own(GtkWidget* widget) {
+  DCHECK(!widget_);
+  // We want to make sure that Own() was called properly, right after the
+  // widget was created.  We should have a floating refcount of 1.
+  DCHECK(g_object_is_floating(widget));
+  // NOTE: Assumes some implementation details about glib internals.
+  DCHECK(G_OBJECT(widget)->ref_count == 1);
+
+  // Sink the floating reference, we should now own this reference.
+  g_object_ref_sink(widget);
+  widget_ = widget;
+}
+
+void OwnedWidgetGtk::Destroy() {
+  if (!widget_)
+    return;
+
+  GtkWidget* widget = widget_;
+  widget_ = NULL;
+  gtk_widget_destroy(widget);
+
+  DCHECK(!g_object_is_floating(widget));
+  // NOTE: Assumes some implementation details about glib internals.
+  DCHECK(G_OBJECT(widget)->ref_count == 1);
+  g_object_unref(widget);
+}