1// Copyright 2014 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 COMPONENTS_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_
6#define COMPONENTS_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_
7
8#include <windows.h>
9#include <bits.h>
10
11#include "base/macros.h"
12#include "base/memory/ref_counted.h"
13#include "base/strings/string16.h"
14#include "base/threading/thread_checker.h"
15#include "base/time/time.h"
16#include "base/timer/timer.h"
17#include "base/win/scoped_comptr.h"
18#include "components/component_updater/crx_downloader.h"
19
20namespace base {
21class FilePath;
22class MessageLoopProxy;
23class SingleThreadTaskRunner;
24}
25
26namespace component_updater {
27
28// Implements a downloader in terms of the BITS service. The public interface
29// of this class and the CrxDownloader overrides are expected to be called
30// from the main thread. The rest of the class code runs on a single thread
31// task runner. This task runner must be initialized to work with COM objects.
32// Instances of this class are created and destroyed in the main thread.
33// See the implementation of the class destructor for details regarding the
34// clean up of resources acquired in this class.
35class BackgroundDownloader : public CrxDownloader {
36 protected:
37  friend class CrxDownloader;
38  BackgroundDownloader(scoped_ptr<CrxDownloader> successor,
39                       net::URLRequestContextGetter* context_getter,
40                       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
41  virtual ~BackgroundDownloader();
42
43 private:
44  // Overrides for CrxDownloader.
45  virtual void DoStartDownload(const GURL& url) OVERRIDE;
46
47  // Called asynchronously on the |task_runner_| at different stages during
48  // the download. |OnDownloading| can be called multiple times.
49  // |EndDownload| switches the execution flow from the |task_runner_| to the
50  // main thread. Accessing any data members of this object from the
51  // |task_runner_|after calling |EndDownload| is unsafe.
52  void BeginDownload(const GURL& url);
53  void OnDownloading();
54  void EndDownload(HRESULT hr);
55
56  // Handles the job state transitions to a final state.
57  void OnStateTransferred();
58  void OnStateError();
59  void OnStateCancelled();
60  void OnStateAcknowledged();
61
62  // Handles the transition to a transient state where the job is in the
63  // queue but not actively transferring data.
64  void OnStateQueued();
65
66  // Handles the job state transition to a transient, non-final error state.
67  void OnStateTransientError();
68
69  // Handles the job state corresponding to transferring data.
70  void OnStateTransferring();
71
72  HRESULT QueueBitsJob(const GURL& url);
73  HRESULT CreateOrOpenJob(const GURL& url);
74  HRESULT InitializeNewJob(const GURL& url);
75
76  // Returns true if at the time of the call, it appears that the job
77  // has not been making progress toward completion.
78  bool IsStuck();
79
80  // Makes the downloaded file available to the caller by renaming the
81  // temporary file to its destination and removing it from the BITS queue.
82  HRESULT CompleteJob();
83
84  // Ensures that we are running on the same thread we created the object on.
85  base::ThreadChecker thread_checker_;
86
87  // Used to post responses back to the main thread. Initialized on the main
88  // loop but accessed from the task runner.
89  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
90
91  net::URLRequestContextGetter* context_getter_;
92  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
93
94  // The timer and the BITS interface pointers have thread affinity. These
95  // members are initialized on the task runner and they must be destroyed
96  // on the task runner.
97  scoped_ptr<base::RepeatingTimer<BackgroundDownloader> > timer_;
98
99  base::win::ScopedComPtr<IBackgroundCopyManager> bits_manager_;
100  base::win::ScopedComPtr<IBackgroundCopyJob> job_;
101
102  // Contains the time when the download of the current url has started.
103  base::Time download_start_time_;
104
105  // Contains the time when the BITS job is last seen making progress.
106  base::Time job_stuck_begin_time_;
107
108  // True if EndDownload was called.
109  bool is_completed_;
110
111  // Contains the path of the downloaded file if the download was successful.
112  base::FilePath response_;
113
114  DISALLOW_COPY_AND_ASSIGN(BackgroundDownloader);
115};
116
117}  // namespace component_updater
118
119#endif  // COMPONENTS_COMPONENT_UPDATER_BACKGROUND_DOWNLOADER_WIN_H_
120