version_loader.h revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
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#ifndef CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_
6#define CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_
7
8#include <string>
9
10#include "base/callback.h"
11#include "base/gtest_prod_util.h"
12#include "base/task/cancelable_task_tracker.h"
13
14namespace chromeos {
15
16// ChromeOSVersionLoader loads the version of Chrome OS from the file system.
17// Loading is done asynchronously in the blocking thread pool. Once loaded,
18// ChromeOSVersionLoader callback to a method of your choice with the version
19// (or an empty string if the version couldn't be found).
20// To use ChromeOSVersionLoader do the following:
21//
22// . In your class define a member field of type chromeos::VersionLoader and
23//   base::CancelableTaskTracker.
24// . Define the callback method, something like:
25//   void OnGetChromeOSVersion(const std::string& version);
26// . When you want the version invoke:
27//   VersionLoader::GetVersion()
28//
29// This class also provides the ability to load the bios firmware using
30//   VersionLoader::GetFirmware()
31class VersionLoader {
32 public:
33  VersionLoader();
34  virtual ~VersionLoader();
35
36  enum VersionFormat {
37    VERSION_SHORT,
38    VERSION_SHORT_WITH_DATE,
39    VERSION_FULL,
40  };
41
42  // Signature
43  typedef base::Callback<void(const std::string&)> GetVersionCallback;
44  typedef base::Callback<void(const std::string&)> GetFirmwareCallback;
45
46  // Asynchronously requests the version.
47  // If |full_version| is true version string with extra info is extracted,
48  // otherwise it's in short format x.x.xx.x.
49  base::CancelableTaskTracker::TaskId GetVersion(
50      VersionFormat format,
51      const GetVersionCallback& callback,
52      base::CancelableTaskTracker* tracker);
53
54  base::CancelableTaskTracker::TaskId GetFirmware(
55      const GetFirmwareCallback& callback,
56      base::CancelableTaskTracker* tracker);
57
58 private:
59  FRIEND_TEST_ALL_PREFIXES(VersionLoaderTest, ParseFirmware);
60
61  // VersionLoader calls into the Backend in the blocking thread pool to load
62  // and extract the version.
63  class Backend : public base::RefCountedThreadSafe<Backend> {
64   public:
65    Backend() {}
66
67    // Gets the version number from base::SysInfo. This is invoked on the
68    // blocking thread pool.
69    void GetVersion(VersionFormat format, std::string* version);
70
71    // Calls ParseFirmware to get the firmware value. This is invoked on the
72    // blocking thread pool.
73    void GetFirmware(std::string* firmware);
74
75   private:
76    friend class base::RefCountedThreadSafe<Backend>;
77
78    ~Backend() {}
79
80    DISALLOW_COPY_AND_ASSIGN(Backend);
81  };
82
83  // Extracts the firmware from the file.
84  static std::string ParseFirmware(const std::string& contents);
85
86  scoped_refptr<Backend> backend_;
87
88  DISALLOW_COPY_AND_ASSIGN(VersionLoader);
89};
90
91}  // namespace chromeos
92
93#endif  // CHROME_BROWSER_CHROMEOS_VERSION_LOADER_H_
94