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      1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
      2 // Use of this source code is governed by a BSD-style license that can be
      3 // found in the LICENSE file.
      4 
      5 #ifndef UI_BASE_GTK_GTK_SIGNAL_REGISTRAR_H_
      6 #define UI_BASE_GTK_GTK_SIGNAL_REGISTRAR_H_
      7 
      8 #include <glib.h>
      9 #include <map>
     10 #include <vector>
     11 
     12 #include "base/basictypes.h"
     13 #include "ui/base/ui_export.h"
     14 
     15 typedef void (*GCallback) (void);
     16 typedef struct _GObject GObject;
     17 typedef struct _GtkWidget GtkWidget;
     18 
     19 namespace ui {
     20 
     21 // A class that ensures that callbacks don't run on stale owner objects. Similar
     22 // in spirit to NotificationRegistrar. Use as follows:
     23 //
     24 //   class ChromeObject {
     25 //    public:
     26 //     ChromeObject() {
     27 //       ...
     28 //
     29 //       signals_.Connect(widget, "event", CallbackThunk, this);
     30 //     }
     31 //
     32 //     ...
     33 //
     34 //    private:
     35 //     GtkSignalRegistrar signals_;
     36 //   };
     37 //
     38 // When |signals_| goes down, it will disconnect the handlers connected via
     39 // Connect.
     40 class UI_EXPORT GtkSignalRegistrar {
     41  public:
     42   GtkSignalRegistrar();
     43   ~GtkSignalRegistrar();
     44 
     45   // Connect before the default handler. Returns the handler id.
     46   glong Connect(gpointer instance, const gchar* detailed_signal,
     47                 GCallback signal_handler, gpointer data);
     48   // Connect after the default handler. Returns the handler id.
     49   glong ConnectAfter(gpointer instance, const gchar* detailed_signal,
     50                      GCallback signal_handler, gpointer data);
     51 
     52   // Disconnects all signal handlers connected to |instance|.
     53   void DisconnectAll(gpointer instance);
     54 
     55  private:
     56   typedef std::vector<glong> HandlerList;
     57   typedef std::map<GObject*, HandlerList> HandlerMap;
     58 
     59   static void WeakNotifyThunk(gpointer data, GObject* where_the_object_was) {
     60     reinterpret_cast<GtkSignalRegistrar*>(data)->WeakNotify(
     61         where_the_object_was);
     62   }
     63   void WeakNotify(GObject* where_the_object_was);
     64 
     65   glong ConnectInternal(gpointer instance, const gchar* detailed_signal,
     66                         GCallback signal_handler, gpointer data, bool after);
     67 
     68   HandlerMap handler_lists_;
     69 
     70   DISALLOW_COPY_AND_ASSIGN(GtkSignalRegistrar);
     71 };
     72 
     73 }  // namespace ui
     74 
     75 #endif  // UI_BASE_GTK_GTK_SIGNAL_REGISTRAR_H_
     76