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#include "base/at_exit.h"
6
7#include <stddef.h>
8#include <ostream>
9
10#include "base/bind.h"
11#include "base/callback.h"
12#include "base/logging.h"
13
14namespace base {
15
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.
22static AtExitManager* g_top_manager = NULL;
23
24AtExitManager::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;
31}
32
33AtExitManager::~AtExitManager() {
34  if (!g_top_manager) {
35    NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
36    return;
37  }
38  DCHECK_EQ(this, g_top_manager);
39
40  ProcessCallbacksNow();
41  g_top_manager = next_manager_;
42}
43
44// static
45void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
46  DCHECK(func);
47  RegisterTask(base::Bind(func, param));
48}
49
50// static
51void AtExitManager::RegisterTask(base::Closure task) {
52  if (!g_top_manager) {
53    NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
54    return;
55  }
56
57  AutoLock lock(g_top_manager->lock_);
58  g_top_manager->stack_.push(task);
59}
60
61// static
62void AtExitManager::ProcessCallbacksNow() {
63  if (!g_top_manager) {
64    NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
65    return;
66  }
67
68  AutoLock lock(g_top_manager->lock_);
69
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();
74  }
75}
76
77AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
78  DCHECK(shadow || !g_top_manager);
79  g_top_manager = this;
80}
81
82}  // namespace base
83