content/browser/download/download_job.h

// Copyright 2017 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 CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_JOB_H_
#define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_JOB_H_

#include "base/macros.h"
#include "base/time/time.h"
#include "content/browser/byte_stream.h"
#include "content/common/content_export.h"
#include "content/public/browser/download_danger_type.h"
#include "content/public/browser/download_interrupt_reasons.h"

namespace content {

class DownloadItemImpl;
class WebContents;

// DownloadJob lives on UI thread and subclasses implement actual download logic
// and interact with DownloadItemImpl.
// The base class is a friend class of DownloadItemImpl.
class CONTENT_EXPORT DownloadJob {
 public:
  explicit DownloadJob(DownloadItemImpl* download_item);
  virtual ~DownloadJob();

  // Download operations.
  virtual void Start() = 0;
  virtual void Cancel(bool user_cancel) = 0;
  virtual void Pause();
  virtual void Resume(bool resume_request);

  bool is_paused() const { return is_paused_; }

  // Return the WebContents associated with the download. Usually used to
  // associate a browser window for any UI that needs to be displayed to the
  // user.
  // Or return nullptr if the download is not associated with an active
  // WebContents.
  virtual WebContents* GetWebContents() const = 0;

  // Returns whether the download uses parallel requests.
  virtual bool UsesParallelRequests() const;

 protected:
  void StartDownload() const;
  void Interrupt(DownloadInterruptReason reason);

  // Add a byte stream to the download sink. Return false if we start to
  // destroy download file.
  bool AddByteStream(std::unique_ptr<ByteStreamReader> stream_reader,
                     int64_t offset,
                     int64_t length);

  DownloadItemImpl* download_item_;

 private:
  // If the download progress is paused by the user.
  bool is_paused_;

  DISALLOW_COPY_AND_ASSIGN(DownloadJob);
};

}  // namespace content

#endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_JOB_H_