Allow multiple AtExitManagers to be chained in a stack, this allows m…

…uch easier testing for code that is expecting to be run via an AtExitManager. This actually cleaned up a lot of the at exit code.

Clean up singleton_dll_unittest.  It is no longer windows specific DLL, and now is much simpler, and builds and runs cross platform.

BUG=1314043

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@646 0039d316-1c4b-4281-b951-d872f2087c98

base/SConscript

@@ -200,23 +200,6 @@ if env['PLATFORM'] == 'win32':
       ],
   )
 
-
-env_tests_dll = env_tests.Clone()
-env_tests_dll.Append(
-    CPPDEFINES = [
-        '_WINDLL',
-        'SINGLETON_UNITTEST_EXPORTS',
-    ],
-)
-dll = env_tests_dll.ChromeSharedLibrary(['singleton_dll_unittest.dll',
-                                   'singleton_dll_unittest.lib',
-                                   'singleton_dll_unittest.ilk',
-                                   'singleton_dll_unittest.pdb'],
-                                  ['singleton_dll_unittest.cc',
-                                   'build/singleton_dll_unittest.def'])
-i = env.Install('$TARGET_ROOT', dll[0])
-env.Alias('base', i)
-
 env_tests.ChromeTestProgram(['debug_message.exe',
                    'debug_message.ilk',
                    'debug_message.pdb'],
@@ -269,8 +252,6 @@ test_files = [
     'win_util_unittest.cc',
     'word_iterator_unittest.cc',
     'wmi_util_unittest.cc',
-
-    dll[1],
 ]
 
 if env['PLATFORM'] == 'win32':

base/at_exit.cc

@@ -30,58 +30,63 @@
 #include "base/at_exit.h"
 #include "base/logging.h"
 
-namespace {
-
-std::stack<base::AtExitCallbackType>* g_atexit_queue = NULL;
-Lock* g_atexit_lock = NULL;
-
-void ProcessCallbacks() {
-  if (!g_atexit_queue)
-    return;
-  base::AtExitCallbackType func = NULL;
-  while(!g_atexit_queue->empty()) {
-    func = g_atexit_queue->top();
-    g_atexit_queue->pop();
-    if (func)
-      func();
-  }
-}
-
-}   // namespace
+// Keep a stack of registered AtExitManagers.  We always operate on the most
+// recent, and we should never have more than one outside of testing, when we
+// use the shadow version of the constructor.  We don't protect this for
+// thread-safe access, since it will only be modified in testing.
+static std::stack<base::AtExitManager*> g_managers;
 
 namespace base {
 
 AtExitManager::AtExitManager() {
-  DCHECK(NULL == g_atexit_queue);
-  DCHECK(NULL == g_atexit_lock);
-  g_atexit_lock = &lock_;
-  g_atexit_queue = &atexit_queue_;
+  DCHECK(g_managers.empty());
+  g_managers.push(this);
+}
+
+AtExitManager::AtExitManager(bool shadow) {
+  DCHECK(shadow || g_managers.empty());
+  g_managers.push(this);
 }
 
 AtExitManager::~AtExitManager() {
-  AutoLock lock(lock_);
-  ProcessCallbacks();
-  g_atexit_queue = NULL;
-  g_atexit_lock = NULL;
+  if (g_managers.empty()) {
+    NOTREACHED() << "Tried to ~AtExitManager without a AtExitManager";
+    return;
+  }
+  DCHECK(g_managers.top() == this);
+
+  ProcessCallbacksNow();
+  g_managers.pop();
 }
 
+// static
 void AtExitManager::RegisterCallback(AtExitCallbackType func) {
-  DCHECK(NULL != g_atexit_queue);
-  DCHECK(NULL != g_atexit_lock);
-  if (!g_atexit_lock)
+  if (g_managers.empty()) {
+    NOTREACHED() << "Tried to RegisterCallback without a AtExitManager";
     return;
-  AutoLock lock(*g_atexit_lock);
-  if (g_atexit_queue)
-    g_atexit_queue->push(func);
+  }
+
+  AtExitManager* manager = g_managers.top();
+  AutoLock lock(manager->lock_);
+  manager->stack_.push(func);
 }
 
+// static
 void AtExitManager::ProcessCallbacksNow() {
-  DCHECK(NULL != g_atexit_lock);
-  if (!g_atexit_lock)
+  if (g_managers.empty()) {
+    NOTREACHED() << "Tried to RegisterCallback without a AtExitManager";
     return;
-  AutoLock lock(*g_atexit_lock);
-  DCHECK(NULL != g_atexit_queue);
-  ProcessCallbacks();
+  }
+
+  AtExitManager* manager = g_managers.top();
+  AutoLock lock(manager->lock_);
+
+  while (!manager->stack_.empty()) {
+    base::AtExitCallbackType func = manager->stack_.top();
+    manager->stack_.pop();
+    if (func)
+      func();
+  }
 }
 
 }  // namespace base

base/at_exit.h

@@ -54,6 +54,12 @@ typedef void (*AtExitCallbackType)();
 // callbacks and singleton destructors will be called.
 
 class AtExitManager {
+ protected:
+  // This constructor will allow this instance of AtExitManager to be created
+  // even if on already exists.  This should only be used for testing!
+  // AtExitManagers are kept on a global stack, and it will be removed during
+  // destruction.  This allows you to shadow another AtExitManager.
+  AtExitManager(bool shadow);
  public:
   AtExitManager();
 
@@ -71,7 +77,7 @@ class AtExitManager {
 
  private:
   Lock lock_;
-  std::stack<base::AtExitCallbackType> atexit_queue_;
+  std::stack<base::AtExitCallbackType> stack_;
   DISALLOW_EVIL_CONSTRUCTORS(AtExitManager);
 };
 

base/base.sln

@@ -36,12 +36,6 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "libpng", "..\third_party\li
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "zlib", "..\third_party\zlib\zlib.vcproj", "{8423AF0D-4B88-4EBF-94E1-E4D00D00E21C}"
 EndProject
-Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "singleton_dll_unittest", "build\singleton_unittest.vcproj", "{E457F2FB-4708-4001-9B1C-275D7BD7F2A8}"
-	ProjectSection(ProjectDependencies) = postProject
-		{1832A374-8A74-4F9E-B536-69A699B3E165} = {1832A374-8A74-4F9E-B536-69A699B3E165}
-		{8C27D792-2648-4F5E-9ED0-374276327308} = {8C27D792-2648-4F5E-9ED0-374276327308}
-	EndProjectSection
-EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "gtest", "..\testing\gtest.vcproj", "{BFE8E2A7-3B3B-43B0-A994-3058B852DB8B}"
 EndProject
 Global