Use ByteStream in downloads system to decouple source and sink.

content/browser/download/download_file_manager.h

 // Copyright (c) 2012 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.
 //
 // The DownloadFileManager owns a set of DownloadFile objects, each of which
 // represent one in progress download and performs the disk IO for that
 // download. The DownloadFileManager itself is a singleton object owned by the
 // ResourceDispatcherHostImpl.
 //
 // The DownloadFileManager uses the file_thread for performing file write
@@ skipping 43 matching lines @@
 #include "content/public/browser/download_id.h"
 #include "content/public/browser/download_interrupt_reasons.h"
 #include "net/base/net_errors.h"
 #include "ui/gfx/native_widget_types.h"
 
 struct DownloadCreateInfo;
 class DownloadRequestHandle;
 class FilePath;
 
 namespace content {
-class DownloadBuffer;
+class ByteStreamReader;
 class DownloadFile;
 class DownloadManager;
 }
 
 namespace net {
 class BoundNetLog;
 }
 
 // Manages all in progress downloads.
 // Methods are virtual to allow mocks--this class is not intended
 // to be a base class.
 class CONTENT_EXPORT DownloadFileManager
     : public base::RefCountedThreadSafe<DownloadFileManager> {
  public:
   // Callback used with RenameInProgressDownloadFile() and
   // RenameCompletingDownloadFile().
   typedef base::Callback<void(const FilePath&)> RenameCompletionCallback;
 
   class DownloadFileFactory {
    public:
     virtual ~DownloadFileFactory() {}
 
     virtual content::DownloadFile* CreateFile(
         DownloadCreateInfo* info,
+        scoped_ptr<content::ByteStreamReader> stream,
         const DownloadRequestHandle& request_handle,
         content::DownloadManager* download_manager,
         bool calculate_hash,
         const net::BoundNetLog& bound_net_log) = 0;
   };
 
   // Takes ownership of the factory.
   // Passing in a NULL for |factory| will cause a default
   // |DownloadFileFactory| to be used.
   explicit DownloadFileManager(DownloadFileFactory* factory);
 
   // Called on shutdown on the UI thread.
   virtual void Shutdown();
 
   // Called on UI thread to make DownloadFileManager start the download.
-  virtual void StartDownload(DownloadCreateInfo* info,
+  virtual void StartDownload(scoped_ptr<DownloadCreateInfo> info,
+                             scoped_ptr<content::ByteStreamReader> stream,
                              const DownloadRequestHandle& request_handle);
 
-  // Handlers for notifications sent from the IO thread and run on the
-  // FILE thread.
-  virtual void UpdateDownload(content::DownloadId global_id,
-                              content::DownloadBuffer* buffer);
-
-  // |reason| is the reason for interruption, if one occurs.
-  // |security_info| contains SSL information (cert_id, cert_status,
-  // security_bits, ssl_connection_status), which can be used to
-  // fine-tune the error message.  It is empty if the transaction
-  // was not performed securely.
-  virtual void OnResponseCompleted(content::DownloadId global_id,
-                                   content::DownloadInterruptReason reason,
-                                   const std::string& security_info);
-
   // Handlers for notifications sent from the UI thread and run on the
   // FILE thread.  These are both terminal actions with respect to the
   // download file, as far as the DownloadFileManager is concerned -- if
   // anything happens to the download file after they are called, it will
   // be ignored.
   virtual void CancelDownload(content::DownloadId id);
   virtual void CompleteDownload(content::DownloadId id);
 
   // Called on FILE thread by DownloadManager at the beginning of its shutdown.
   virtual void OnDownloadManagerShutdown(content::DownloadManager* manager);
@@ skipping 48 matching lines @@
   // Timer helpers for updating the UI about the current progress of a download.
   void StartUpdateTimer();
   void StopUpdateTimer();
   void UpdateInProgressDownloads();
 
   // Clean up helper that runs on the download thread.
   void OnShutdown();
 
   // Creates DownloadFile on FILE thread and continues starting the download
   // process.
-  void CreateDownloadFile(DownloadCreateInfo* info,
+  void CreateDownloadFile(scoped_ptr<DownloadCreateInfo> info,
+                          scoped_ptr<content::ByteStreamReader> stream,
                           const DownloadRequestHandle& request_handle,
                           content::DownloadManager* download_manager,
                           bool hash_needed,
                           const net::BoundNetLog& bound_net_log);
 
   // Called only on the download thread.
   content::DownloadFile* GetDownloadFile(content::DownloadId global_id);
 
   // Called only from RenameInProgressDownloadFile and
   // RenameCompletingDownloadFile on the FILE thread.
@@ skipping 10 matching lines @@
 
   // A map of all in progress downloads.  It owns the download files.
   DownloadFileMap downloads_;
 
   scoped_ptr<DownloadFileFactory> download_file_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadFileManager);
 };
 
 #endif  // CONTENT_BROWSER_DOWNLOAD_DOWNLOAD_FILE_MANAGER_H_