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// Copyright (c) 2011 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.
#ifndef UI_BASE_GTK_G_OBJECT_DESTRUCTOR_FILO_H_
#define UI_BASE_GTK_G_OBJECT_DESTRUCTOR_FILO_H_
#pragma once
#include <glib.h>
#include <map>
#include <list>
#include "base/memory/singleton.h"
typedef struct _GObject GObject;
namespace ui {
// This class hooks calls to g_object_weak_ref()/unref() and executes them in
// FILO order. This is important if there are several hooks to the single object
// (set up at different levels of class hierarchy) and the lowest hook (set up
// first) is deleting self - it must be called last (among hooks for the given
// object). Unfortunately Glib does not provide this guarantee.
//
// Use it as follows:
//
// static void OnDestroyedThunk(gpointer data, GObject *where_the_object_was) {
// reinterpret_cast<MyClass*>(data)->OnDestroyed(where_the_object_was);
// }
// void MyClass::OnDestroyed(GObject *where_the_object_was) {
// destroyed_ = true;
// delete this;
// }
// MyClass::Init() {
// ...
// ui::GObjectDestructorFILO::GetInstance()->Connect(
// G_OBJECT(my_widget), &OnDestroyedThunk, this);
// }
// MyClass::~MyClass() {
// if (!destroyed_) {
// ui::GObjectDestructorFILO::GetInstance()->Disconnect(
// G_OBJECT(my_widget), &OnDestroyedThunk, this);
// }
// }
//
// TODO(glotov): Probably worth adding ScopedGObjectDtor<T>.
//
// This class is a singleton. Not thread safe. Must be called within UI thread.
class GObjectDestructorFILO {
public:
typedef void (*DestructorHook)(void* context, GObject* where_the_object_was);
static GObjectDestructorFILO* GetInstance();
void Connect(GObject* object, DestructorHook callback, void* context);
void Disconnect(GObject* object, DestructorHook callback, void* context);
private:
struct Hook {
Hook(GObject* o, DestructorHook cb, void* ctx)
: object(o), callback(cb), context(ctx) {
}
bool equal(GObject* o, DestructorHook cb, void* ctx) const {
return object == o && callback == cb && context == ctx;
}
GObject* object;
DestructorHook callback;
void* context;
};
typedef std::list<Hook> HandlerList;
typedef std::map<GObject*, HandlerList> HandlerMap;
GObjectDestructorFILO();
~GObjectDestructorFILO();
friend struct DefaultSingletonTraits<GObjectDestructorFILO>;
void WeakNotify(GObject* where_the_object_was);
static void WeakNotifyThunk(gpointer data, GObject* where_the_object_was) {
reinterpret_cast<GObjectDestructorFILO*>(data)->WeakNotify(
where_the_object_was);
}
HandlerMap handler_map_;
DISALLOW_COPY_AND_ASSIGN(GObjectDestructorFILO);
};
} // namespace ui
#endif // UI_BASE_GTK_G_OBJECT_DESTRUCTOR_FILO_H_
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