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

3 files changed, 127 insertions, 2 deletions

diff --git a/app/app_base.gypi b/app/app_base.gypi
index 2eaa8f6..802a0d2 100644
--- a/app/app_base.gypi
+++ b/app/app_base.gypi
@@ -47,6 +47,7 @@
             'sources!': [
               'gtk_dnd_util.cc',
               'gtk_dnd_util.h',
+              'gtk_signal.cc',
               'gtk_signal.h',
               'gtk_util.cc',
               'gtk_util.h',
@@ -118,6 +119,7 @@
         'gfx/font_util.cc',
         'gtk_dnd_util.cc',
         'gtk_dnd_util.h',
+        'gtk_signal.cc',
         'gtk_signal.h',
         'gtk_util.cc',
         'gtk_util.h',
diff --git a/app/gtk_signal.cc b/app/gtk_signal.cc
new file mode 100644
index 0000000..4db611d
--- /dev/null
+++ b/app/gtk_signal.cc
@@ -0,0 +1,72 @@
+// Copyright (c) 2010 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 "app/gtk_signal.h"
+
+#include "base/logging.h"
+
+GtkSignalRegistrar::GtkSignalRegistrar() {
+}
+
+GtkSignalRegistrar::~GtkSignalRegistrar() {
+  for (HandlerMap::iterator list_iter = handler_lists_.begin();
+       list_iter != handler_lists_.end(); ++list_iter) {
+    GObject* object = list_iter->first;
+    g_object_weak_unref(object, WeakNotifyThunk, this);
+
+    HandlerList& handlers = list_iter->second;
+    for (HandlerList::iterator ids_iter = handlers.begin();
+         ids_iter != handlers.end(); ids_iter++) {
+      g_signal_handler_disconnect(list_iter->first, *ids_iter);
+    }
+  }
+}
+
+glong GtkSignalRegistrar::Connect(gpointer instance,
+                                  const gchar* detailed_signal,
+                                  GCallback signal_handler,
+                                  gpointer data) {
+  return ConnectInternal(instance, detailed_signal, signal_handler, data,
+                         false);
+}
+
+glong GtkSignalRegistrar::ConnectAfter(gpointer instance,
+                                       const gchar* detailed_signal,
+                                       GCallback signal_handler,
+                                       gpointer data) {
+  return ConnectInternal(instance, detailed_signal, signal_handler, data, true);
+}
+
+glong GtkSignalRegistrar::ConnectInternal(gpointer instance,
+                                          const gchar* detailed_signal,
+                                          GCallback signal_handler,
+                                          gpointer data,
+                                          bool after) {
+  GObject* object = G_OBJECT(instance);
+
+  HandlerMap::iterator iter = handler_lists_.find(object);
+  if (iter == handler_lists_.end()) {
+    g_object_weak_ref(object, WeakNotifyThunk, this);
+    handler_lists_[object] = HandlerList();
+    iter = handler_lists_.find(object);
+  }
+
+  glong handler_id = after ?
+      g_signal_connect_after(instance, detailed_signal, signal_handler, data) :
+      g_signal_connect(instance, detailed_signal, signal_handler, data);
+  iter->second.push_back(handler_id);
+
+  return handler_id;
+}
+
+void GtkSignalRegistrar::WeakNotify(GObject* where_the_object_was) {
+  HandlerMap::iterator iter = handler_lists_.find(where_the_object_was);
+  if (iter == handler_lists_.end()) {
+    NOTREACHED();
+    return;
+  }
+  // The signal handlers will be disconnected automatically. Just erase the
+  // handler id list.
+  handler_lists_.erase(iter);
+}
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_