// Copyright (c) 2009 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 CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_ #define CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_ #pragma once #include <string> #include "base/callback.h" #include "base/gtest_prod_util.h" #include "chrome/browser/cancelable_request.h" class FilePath; namespace chromeos { // ChromeOSVersionLoader loads the version of Chrome OS from the file system. // Loading is done asynchronously on the file thread. Once loaded, // ChromeOSVersionLoader callsback to a method of your choice with the version // (or an empty string if the version couldn't be found). // To use ChromeOSVersionLoader do the following: // // . In your class define a member field of type chromeos::VersionLoader and // CancelableRequestConsumerBase. // . Define the callback method, something like: // void OnGetChromeOSVersion(chromeos::VersionLoader::Handle, // std::string version); // . When you want the version invoke: loader.GetVersion(&consumer, callback); class VersionLoader : public CancelableRequestProvider { public: VersionLoader(); // Signature typedef Callback2<Handle, std::string>::Type GetVersionCallback; typedef CancelableRequest<GetVersionCallback> GetVersionRequest; // Asynchronously requests the version. Handle GetVersion(CancelableRequestConsumerBase* consumer, GetVersionCallback* callback); private: FRIEND_TEST_ALL_PREFIXES(VersionLoaderTest, ParseVersion); // VersionLoader calls into the Backend on the file thread to load // and extract the version. class Backend : public base::RefCountedThreadSafe<Backend> { public: Backend() {} // Calls ParseVersion to get the version # and notifies request. // This is invoked on the file thread. void GetVersion(scoped_refptr<GetVersionRequest> request); private: friend class base::RefCountedThreadSafe<Backend>; ~Backend() {} DISALLOW_COPY_AND_ASSIGN(Backend); }; // Extracts the version from the file. static std::string ParseVersion(const std::string& contents); scoped_refptr<Backend> backend_; DISALLOW_COPY_AND_ASSIGN(VersionLoader); }; } // namespace chromeos #endif // CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_