GTK: Add a scoping class for g signals.

BUG=40735
TEST=compile; trybots; manually opening and closing a lot of infobubbles

Review URL: http://codereview.chromium.org/1652005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44821 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 53 insertions, 2 deletions

diff --git a/app/gtk_signal.h b/app/gtk_signal.h
index a3d5f7a..ffa487b 100644
--- a/app/gtk_signal.h
+++ b/app/gtk_signal.h
@@ -5,8 +5,11 @@
 #ifndef APP_GTK_SIGNAL_H_
 #define APP_GTK_SIGNAL_H_
 
-typedef void* gpointer;
-typedef struct _GtkWidget GtkWidget;
+#include <gtk/gtk.h>
+#include <map>
+#include <vector>
+
+#include "base/basictypes.h"
 
 // At the time of writing this, there were two common ways of binding our C++
 // code to the gobject C system. We either defined a whole bunch of "static
@@ -113,4 +116,52 @@ typedef struct _GtkWidget GtkWidget;
   CHROMEG_CALLBACK_6(CLASS, RETURN, METHOD, GtkWidget*, ARG1, ARG2, ARG3,   \
                      ARG4, ARG5, ARG6);
 
+// A class that ensures that callbacks don't run on stale owner objects. Similar
+// in spirit to NotificationRegistrar. Use as follows:
+//
+//   class ChromeObject {
+//    public:
+//     ChromeObject() {
+//       ...
+//
+//       signals_.Connect(widget, "event", CallbackThunk, this);
+//     }
+//
+//     ...
+//
+//    private:
+//     GtkSignalRegistrar signals_;
+//   };
+//
+// When |signals_| goes down, it will disconnect the handlers connected via
+// Connect.
+class GtkSignalRegistrar {
+ public:
+  GtkSignalRegistrar();
+  ~GtkSignalRegistrar();
+
+  // Connect before the default handler. Returns the handler id.
+  glong Connect(gpointer instance, const gchar* detailed_signal,
+                GCallback signal_handler, gpointer data);
+  // Connect after the default handler. Returns the handler id.
+  glong ConnectAfter(gpointer instance, const gchar* detailed_signal,
+                     GCallback signal_handler, gpointer data);
+
+ private:
+  static void WeakNotifyThunk(gpointer data, GObject* where_the_object_was) {
+    reinterpret_cast<GtkSignalRegistrar*>(data)->WeakNotify(
+        where_the_object_was);
+  }
+  void WeakNotify(GObject* where_the_object_was);
+
+  glong ConnectInternal(gpointer instance, const gchar* detailed_signal,
+                        GCallback signal_handler, gpointer data, bool after);
+
+  typedef std::vector<glong> HandlerList;
+  typedef std::map<GObject*, HandlerList> HandlerMap;
+  HandlerMap handler_lists_;
+
+  DISALLOW_COPY_AND_ASSIGN(GtkSignalRegistrar);
+};
+
 #endif  // APP_GTK_SIGNAL_H_