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[chromium-blink-merge.git] / base / at_exit.cc
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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.
5 #include "base/at_exit.h"
7 #include <stddef.h>
8 #include <ostream>
10 #include "base/bind.h"
11 #include "base/callback.h"
12 #include "base/logging.h"
14 namespace base {
16 // Keep a stack of registered AtExitManagers. We always operate on the most
17 // recent, and we should never have more than one outside of testing (for a
18 // statically linked version of this library). Testing may use the shadow
19 // version of the constructor, and if we are building a dynamic library we may
20 // end up with multiple AtExitManagers on the same process. We don't protect
21 // this for thread-safe access, since it will only be modified in testing.
22 static AtExitManager* g_top_manager = NULL;
24 AtExitManager::AtExitManager() : next_manager_(g_top_manager) {
25 // If multiple modules instantiate AtExitManagers they'll end up living in this
26 // module... they have to coexist.
27 #if !defined(COMPONENT_BUILD)
28 DCHECK(!g_top_manager);
29 #endif
30 g_top_manager = this;
33 AtExitManager::~AtExitManager() {
34 if (!g_top_manager) {
35 NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
36 return;
38 DCHECK_EQ(this, g_top_manager);
40 ProcessCallbacksNow();
41 g_top_manager = next_manager_;
44 // static
45 void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
46 DCHECK(func);
47 RegisterTask(base::Bind(func, param));
50 // static
51 void AtExitManager::RegisterTask(base::Closure task) {
52 if (!g_top_manager) {
53 NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
54 return;
57 AutoLock lock(g_top_manager->lock_);
58 g_top_manager->stack_.push(task);
61 // static
62 void AtExitManager::ProcessCallbacksNow() {
63 if (!g_top_manager) {
64 NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
65 return;
68 AutoLock lock(g_top_manager->lock_);
70 while (!g_top_manager->stack_.empty()) {
71 base::Closure task = g_top_manager->stack_.top();
72 task.Run();
73 g_top_manager->stack_.pop();
77 AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
78 DCHECK(shadow || !g_top_manager);
79 g_top_manager = this;
82 } // namespace base