base/at_exit.cc

   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/logging.h"
  11
  12 namespace base {
  13
  14 // Keep a stack of registered AtExitManagers.  We always operate on the most
  15 // recent, and we should never have more than one outside of testing, when we
  16 // use the shadow version of the constructor.  We don't protect this for
  17 // thread-safe access, since it will only be modified in testing.
  18 static AtExitManager* g_top_manager = NULL;
  19
  20 AtExitManager::AtExitManager() : next_manager_(NULL) {
  21   DCHECK(!g_top_manager);
  22   g_top_manager = this;
  23 }
  24
  25 AtExitManager::~AtExitManager() {
  26   if (!g_top_manager) {
  27     NOTREACHED() << "Tried to ~AtExitManager without an AtExitManager";
  28     return;
  29   }
  30   DCHECK(g_top_manager == this);
  31
  32   ProcessCallbacksNow();
  33   g_top_manager = next_manager_;
  34 }
  35
  36 // static
  37 void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
  38   if (!g_top_manager) {
  39     NOTREACHED() << "Tried to RegisterCallback without an AtExitManager";
  40     return;
  41   }
  42
  43   DCHECK(func);
  44
  45   AutoLock lock(g_top_manager->lock_);
  46   g_top_manager->stack_.push(CallbackAndParam(func, param));
  47 }
  48
  49 // static
  50 void AtExitManager::ProcessCallbacksNow() {
  51   if (!g_top_manager) {
  52     NOTREACHED() << "Tried to ProcessCallbacksNow without an AtExitManager";
  53     return;
  54   }
  55
  56   AutoLock lock(g_top_manager->lock_);
  57
  58   while (!g_top_manager->stack_.empty()) {
  59     CallbackAndParam callback_and_param = g_top_manager->stack_.top();
  60     g_top_manager->stack_.pop();
  61
  62     callback_and_param.func_(callback_and_param.param_);
  63   }
  64 }
  65
  66 AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
  67   DCHECK(shadow || !g_top_manager);
  68   g_top_manager = this;
  69 }
  70
  71 }  // namespace base