components/update_client/background_downloader_win.h

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