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// 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 SequencedTaskRunner;
}
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 sequenced
// task runner, usually associated with a blocking thread pool. The task runner
// must initialize COM.
//
// This class manages a COM client for Windows BITS. The client uses polling,
// triggered by an one-shot timer, to get state updates from BITS. Since the
// timer has thread afinity, the callbacks from the timer are delegated to
// a sequenced task runner, which handles all client COM interaction with
// the BITS service.
class BackgroundDownloader : public CrxDownloader {
protected:
friend class CrxDownloader;
BackgroundDownloader(
scoped_ptr<CrxDownloader> successor,
net::URLRequestContextGetter* context_getter,
const scoped_refptr<base::SequencedTaskRunner>& task_runner);
~BackgroundDownloader() override;
private:
// Overrides for CrxDownloader.
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);
HRESULT BeginDownloadHelper(const GURL& url);
// Handles the job state transitions to a final state. Returns true always
// since the download has reached a final state and no further processing for
// this download is needed.
bool OnStateTransferred();
bool OnStateError();
bool OnStateCancelled();
bool OnStateAcknowledged();
// Handles the transition to a transient state where the job is in the
// queue but not actively transferring data. Returns true if the download has
// been in this state for too long and it will be abandoned, or false, if
// further processing for this download is needed.
bool OnStateQueued();
// Handles the job state transition to a transient error state, which may or
// may not be considered final, depending on the error. Returns true if
// the state is final, or false, if the download is allowed to continue.
bool OnStateTransientError();
// Handles the job state corresponding to transferring data. Returns false
// always since this is never a final state.
bool OnStateTransferring();
void StartTimer();
void OnTimer();
HRESULT QueueBitsJob(const GURL& url, IBackgroundCopyJob** job);
HRESULT CreateOrOpenJob(const GURL& url, IBackgroundCopyJob** job);
HRESULT InitializeNewJob(
const base::win::ScopedComPtr<IBackgroundCopyJob>& job,
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();
// Revokes the interface pointers from GIT.
HRESULT ClearGit();
// Updates the BITS interface pointers so that they can be used by the
// thread calling the function. Call this function to get valid COM interface
// pointers when a thread from the thread pool enters the object.
HRESULT UpdateInterfacePointers();
// Resets the BITS interface pointers. Call this function when a thread
// from the thread pool leaves the object to release the interface pointers.
void ResetInterfacePointers();
// Ensures that we are running on the same thread we created the object on.
base::ThreadChecker thread_checker_;
net::URLRequestContextGetter* context_getter_;
// The timer has thread affinity. This member is initialized and destroyed
// on the main task runner.
scoped_ptr<base::OneShotTimer> timer_;
DWORD git_cookie_bits_manager_;
DWORD git_cookie_job_;
// COM interface pointers are valid for the thread that called
// |UpdateInterfacePointers| to get pointers to COM proxies, which are valid
// for that thread only.
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_;
// 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_
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