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/bind.h"
  11 #include "base/callback.h"
  12 #include "base/logging.h"
  13
  14 namespace 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.
  22 static AtExitManager* g_top_manager = NULL;
  23
  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;
  31 }
  32
  33 AtExitManager::~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
  45 void AtExitManager::RegisterCallback(AtExitCallbackType func, void* param) {
  46   DCHECK(func);
  47   RegisterTask(base::Bind(func, param));
  48 }
  49
  50 // static
  51 void 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
  62 void 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
  77 AtExitManager::AtExitManager(bool shadow) : next_manager_(g_top_manager) {
  78   DCHECK(shadow || !g_top_manager);
  79   g_top_manager = this;
  80 }
  81
  82 }  // namespace base