Move most of the component updater artifacts to update_client.

components/update_client/background_downloader_win.h

+// Copyright 2014 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 COMPONENTS_UPDATE_CLIENT_BACKGROUND_DOWNLOADER_WIN_H_
+#define COMPONENTS_UPDATE_CLIENT_BACKGROUND_DOWNLOADER_WIN_H_
+
+#include <windows.h>
+#include <bits.h>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/strings/string16.h"
+#include "base/threading/thread_checker.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "base/win/scoped_comptr.h"
+#include "components/update_client/crx_downloader.h"
+
+namespace base {
+class FilePath;
+class MessageLoopProxy;
+class SingleThreadTaskRunner;
+}
+
+namespace update_client {
+
+// Implements a downloader in terms of the BITS service. The public interface
+// of this class and the CrxDownloader overrides are expected to be called
+// from the main thread. The rest of the class code runs on a single thread
+// task runner. This task runner must be initialized to work with COM objects.
+// Instances of this class are created and destroyed in the main thread.
+// See the implementation of the class destructor for details regarding the
+// clean up of resources acquired in this class.
+class BackgroundDownloader : public CrxDownloader {
+ protected:
+  friend class CrxDownloader;
+  BackgroundDownloader(scoped_ptr<CrxDownloader> successor,
+                       net::URLRequestContextGetter* context_getter,
+                       scoped_refptr<base::SingleThreadTaskRunner> task_runner);
+  virtual ~BackgroundDownloader();
+
+ private:
+  // Overrides for CrxDownloader.
+  virtual void DoStartDownload(const GURL& url) override;
+
+  // Called asynchronously on the |task_runner_| at different stages during
+  // the download. |OnDownloading| can be called multiple times.
+  // |EndDownload| switches the execution flow from the |task_runner_| to the
+  // main thread. Accessing any data members of this object from the
+  // |task_runner_|after calling |EndDownload| is unsafe.
+  void BeginDownload(const GURL& url);
+  void OnDownloading();
+  void EndDownload(HRESULT hr);
+
+  // Handles the job state transitions to a final state.
+  void OnStateTransferred();
+  void OnStateError();
+  void OnStateCancelled();
+  void OnStateAcknowledged();
+
+  // Handles the transition to a transient state where the job is in the
+  // queue but not actively transferring data.
+  void OnStateQueued();
+
+  // Handles the job state transition to a transient, non-final error state.
+  void OnStateTransientError();
+
+  // Handles the job state corresponding to transferring data.
+  void OnStateTransferring();
+
+  HRESULT QueueBitsJob(const GURL& url);
+  HRESULT CreateOrOpenJob(const GURL& url);
+  HRESULT InitializeNewJob(const GURL& url);
+
+  // Returns true if at the time of the call, it appears that the job
+  // has not been making progress toward completion.
+  bool IsStuck();
+
+  // Makes the downloaded file available to the caller by renaming the
+  // temporary file to its destination and removing it from the BITS queue.
+  HRESULT CompleteJob();
+
+  // Ensures that we are running on the same thread we created the object on.
+  base::ThreadChecker thread_checker_;
+
+  // Used to post responses back to the main thread. Initialized on the main
+  // loop but accessed from the task runner.
+  scoped_refptr<base::SingleThreadTaskRunner> main_task_runner_;
+
+  net::URLRequestContextGetter* context_getter_;
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+
+  // The timer and the BITS interface pointers have thread affinity. These
+  // members are initialized on the task runner and they must be destroyed
+  // on the task runner.
+  scoped_ptr<base::RepeatingTimer<BackgroundDownloader>> timer_;
+
+  base::win::ScopedComPtr<IBackgroundCopyManager> bits_manager_;
+  base::win::ScopedComPtr<IBackgroundCopyJob> job_;
+
+  // Contains the time when the download of the current url has started.
+  base::Time download_start_time_;
+
+  // Contains the time when the BITS job is last seen making progress.
+  base::Time job_stuck_begin_time_;
+
+  // True if EndDownload was called.
+  bool is_completed_;
+
+  // Contains the path of the downloaded file if the download was successful.
+  base::FilePath response_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundDownloader);
+};
+
+}  // namespace update_client
+
+#endif  // COMPONENTS_UPDATE_CLIENT_BACKGROUND_DOWNLOADER_WIN_H_