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      1 // Copyright (c) 2012 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 CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_
      6 #define CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_
      7 
      8 #include <string>
      9 
     10 #include "base/callback.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/timer/timer.h"
     13 #include "content/browser/loader/resource_handler.h"
     14 #include "content/public/browser/download_interrupt_reasons.h"
     15 #include "content/public/browser/download_manager.h"
     16 #include "content/public/browser/download_save_info.h"
     17 #include "content/public/browser/download_url_parameters.h"
     18 
     19 namespace net {
     20 class URLRequest;
     21 }  // namespace net
     22 
     23 namespace content {
     24 class ByteStreamReader;
     25 class ByteStreamWriter;
     26 class DownloadRequestHandle;
     27 class PowerSaveBlocker;
     28 struct DownloadCreateInfo;
     29 
     30 // Forwards data to the download thread.
     31 class CONTENT_EXPORT DownloadResourceHandler
     32     : public ResourceHandler,
     33       public base::SupportsWeakPtr<DownloadResourceHandler> {
     34  public:
     35   struct DownloadTabInfo;
     36 
     37   // Size of the buffer used between the DownloadResourceHandler and the
     38   // downstream receiver of its output.
     39   static const int kDownloadByteStreamSize;
     40 
     41   // started_cb will be called exactly once on the UI thread.
     42   // |id| should be invalid if the id should be automatically assigned.
     43   DownloadResourceHandler(
     44       uint32 id,
     45       net::URLRequest* request,
     46       const DownloadUrlParameters::OnStartedCallback& started_cb,
     47       scoped_ptr<DownloadSaveInfo> save_info);
     48 
     49   virtual bool OnUploadProgress(uint64 position, uint64 size) OVERRIDE;
     50 
     51   virtual bool OnRequestRedirected(const net::RedirectInfo& redirect_info,
     52                                    ResourceResponse* response,
     53                                    bool* defer) OVERRIDE;
     54 
     55   // Send the download creation information to the download thread.
     56   virtual bool OnResponseStarted(ResourceResponse* response,
     57                                  bool* defer) OVERRIDE;
     58 
     59   // Pass-through implementation.
     60   virtual bool OnWillStart(const GURL& url, bool* defer) OVERRIDE;
     61 
     62   // Pass-through implementation.
     63   virtual bool OnBeforeNetworkStart(const GURL& url, bool* defer) OVERRIDE;
     64 
     65   // Create a new buffer, which will be handed to the download thread for file
     66   // writing and deletion.
     67   virtual bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
     68                           int* buf_size,
     69                           int min_size) OVERRIDE;
     70 
     71   virtual bool OnReadCompleted(int bytes_read, bool* defer) OVERRIDE;
     72 
     73   virtual void OnResponseCompleted(const net::URLRequestStatus& status,
     74                                    const std::string& security_info,
     75                                    bool* defer) OVERRIDE;
     76 
     77   // N/A to this flavor of DownloadHandler.
     78   virtual void OnDataDownloaded(int bytes_downloaded) OVERRIDE;
     79 
     80   void PauseRequest();
     81   void ResumeRequest();
     82 
     83   // May result in this object being deleted by its owner.
     84   void CancelRequest();
     85 
     86   std::string DebugString() const;
     87 
     88  private:
     89   virtual ~DownloadResourceHandler();
     90 
     91   // Arrange for started_cb_ to be called on the UI thread with the
     92   // below values, nulling out started_cb_.  Should only be called
     93   // on the IO thread.
     94   void CallStartedCB(DownloadItem* item,
     95                      DownloadInterruptReason interrupt_reason);
     96 
     97   uint32 download_id_;
     98   // This is read only on the IO thread, but may only
     99   // be called on the UI thread.
    100   DownloadUrlParameters::OnStartedCallback started_cb_;
    101   scoped_ptr<DownloadSaveInfo> save_info_;
    102 
    103   // Stores information about the download that must be acquired on the UI
    104   // thread before StartOnUIThread is called.
    105   // Created on IO thread, but only accessed on UI thread. |tab_info_| holds
    106   // the pointer until we pass it off to StartOnUIThread or DeleteSoon.
    107   DownloadTabInfo* tab_info_;
    108 
    109   // Data flow
    110   scoped_refptr<net::IOBuffer> read_buffer_;       // From URLRequest.
    111   scoped_ptr<ByteStreamWriter> stream_writer_; // To rest of system.
    112 
    113   // Keeps the system from sleeping while this ResourceHandler is alive. If the
    114   // system enters power saving mode while a request is alive, it can cause the
    115   // request to fail and the associated download will be interrupted.
    116   scoped_ptr<PowerSaveBlocker> power_save_blocker_;
    117 
    118   // The following are used to collect stats.
    119   base::TimeTicks download_start_time_;
    120   base::TimeTicks last_read_time_;
    121   base::TimeTicks last_stream_pause_time_;
    122   base::TimeDelta total_pause_time_;
    123   size_t last_buffer_size_;
    124   int64 bytes_read_;
    125 
    126   int pause_count_;
    127   bool was_deferred_;
    128 
    129   // For DCHECKing
    130   bool on_response_started_called_;
    131 
    132   static const int kReadBufSize = 32768;  // bytes
    133   static const int kThrottleTimeMs = 200;  // milliseconds
    134 
    135   DISALLOW_COPY_AND_ASSIGN(DownloadResourceHandler);
    136 };
    137 
    138 }  // namespace content
    139 
    140 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_RESOURCE_HANDLER_H_
    141