Autofill phone number enhancements and integration of Phone Number Util Library: part 1

third_party/libphonenumber/cpp/src/base/at_exit.h

+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_AT_EXIT_H_
+#define BASE_AT_EXIT_H_
+#pragma once
+
+#include <stack>
+
+#include "base/basictypes.h"
+#include "base/synchronization/lock.h"
+
+namespace base {
+
+// This class provides a facility similar to the CRT atexit(), except that
+// we control when the callbacks are executed. Under Windows for a DLL they
+// happen at a really bad time and under the loader lock. This facility is
+// mostly used by base::Singleton.
+//
+// The usage is simple. Early in the main() or WinMain() scope create an
+// AtExitManager object on the stack:
+// int main(...) {
+//    base::AtExitManager exit_manager;
+//
+// }
+// When the exit_manager object goes out of scope, all the registered
+// callbacks and singleton destructors will be called.
+
+class AtExitManager {
+ public:
+  typedef void (*AtExitCallbackType)(void*);
+
+  AtExitManager();
+
+  // The dtor calls all the registered callbacks. Do not try to register more
+  // callbacks after this point.
+  ~AtExitManager();
+
+  // Registers the specified function to be called at exit. The prototype of
+  // the callback function is void func().
+  static void RegisterCallback(AtExitCallbackType func, void* param);
+
+  // Calls the functions registered with RegisterCallback in LIFO order. It
+  // is possible to register new callbacks after calling this function.
+  static void ProcessCallbacksNow();
+
+ protected:
+  // This constructor will allow this instance of AtExitManager to be created
+  // even if one 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.
+  explicit AtExitManager(bool shadow);
+
+ private:
+  struct CallbackAndParam {
+    CallbackAndParam(AtExitCallbackType func, void* param)
+        : func_(func), param_(param) { }
+    AtExitCallbackType func_;
+    void* param_;
+  };
+
+  base::Lock lock_;
+  std::stack<CallbackAndParam> stack_;
+  AtExitManager* next_manager_;  // Stack of managers to allow shadowing.
+
+  DISALLOW_COPY_AND_ASSIGN(AtExitManager);
+};
+
+#if defined(UNIT_TEST)
+class ShadowingAtExitManager : public AtExitManager {
+ public:
+  ShadowingAtExitManager() : AtExitManager(true) {}
+};
+#endif  // defined(UNIT_TEST)
+
+}  // namespace base
+
+#endif  // BASE_AT_EXIT_H_