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[chromium-blink-merge.git] / chrome / browser / ui / libgtk2ui / g_object_destructor_filo.h
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1 // Copyright (c) 2012 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.
5 #ifndef CHROME_BROWSER_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_
6 #define CHROME_BROWSER_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_
8 #include <glib.h>
9 #include <list>
10 #include <map>
12 #include "base/basictypes.h"
14 namespace base {
15 template <typename T> struct DefaultSingletonTraits;
18 typedef struct _GObject GObject;
20 namespace libgtk2ui {
22 // This class hooks calls to g_object_weak_ref()/unref() and executes them in
23 // FILO order. This is important if there are several hooks to the single object
24 // (set up at different levels of class hierarchy) and the lowest hook (set up
25 // first) is deleting self - it must be called last (among hooks for the given
26 // object). Unfortunately Glib does not provide this guarantee.
28 // Use it as follows:
30 // static void OnDestroyedThunk(gpointer data, GObject *where_the_object_was) {
31 // reinterpret_cast<MyClass*>(data)->OnDestroyed(where_the_object_was);
32 // }
33 // void MyClass::OnDestroyed(GObject *where_the_object_was) {
34 // destroyed_ = true;
35 // delete this;
36 // }
37 // MyClass::Init() {
38 // ...
39 // ui::GObjectDestructorFILO::GetInstance()->Connect(
40 // G_OBJECT(my_widget), &OnDestroyedThunk, this);
41 // }
42 // MyClass::~MyClass() {
43 // if (!destroyed_) {
44 // ui::GObjectDestructorFILO::GetInstance()->Disconnect(
45 // G_OBJECT(my_widget), &OnDestroyedThunk, this);
46 // }
47 // }
49 // TODO(glotov): Probably worth adding ScopedGObjectDtor<T>.
51 // This class is a singleton. Not thread safe. Must be called within UI thread.
52 class GObjectDestructorFILO {
53 public:
54 typedef void (*DestructorHook)(void* context, GObject* where_the_object_was);
56 static GObjectDestructorFILO* GetInstance();
57 void Connect(GObject* object, DestructorHook callback, void* context);
58 void Disconnect(GObject* object, DestructorHook callback, void* context);
60 private:
61 struct Hook {
62 Hook(GObject* o, DestructorHook cb, void* ctx)
63 : object(o), callback(cb), context(ctx) {
65 bool equal(GObject* o, DestructorHook cb, void* ctx) const {
66 return object == o && callback == cb && context == ctx;
68 GObject* object;
69 DestructorHook callback;
70 void* context;
72 typedef std::list<Hook> HandlerList;
73 typedef std::map<GObject*, HandlerList> HandlerMap;
75 GObjectDestructorFILO();
76 ~GObjectDestructorFILO();
77 friend struct base::DefaultSingletonTraits<GObjectDestructorFILO>;
79 void WeakNotify(GObject* where_the_object_was);
80 static void WeakNotifyThunk(gpointer data, GObject* where_the_object_was) {
81 reinterpret_cast<GObjectDestructorFILO*>(data)->WeakNotify(
82 where_the_object_was);
85 HandlerMap handler_map_;
87 DISALLOW_COPY_AND_ASSIGN(GObjectDestructorFILO);
90 } // namespace libgtk2ui
92 #endif // CHROME_BROWSER_UI_LIBGTK2UI_G_OBJECT_DESTRUCTOR_FILO_H_