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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_LOADER_REDIRECT_TO_FILE_RESOURCE_HANDLER_H_
      6 #define CONTENT_BROWSER_LOADER_REDIRECT_TO_FILE_RESOURCE_HANDLER_H_
      7 
      8 #include "base/basictypes.h"
      9 #include "base/callback.h"
     10 #include "base/compiler_specific.h"
     11 #include "base/files/file.h"
     12 #include "base/files/file_path.h"
     13 #include "base/memory/ref_counted.h"
     14 #include "base/memory/scoped_ptr.h"
     15 #include "base/memory/weak_ptr.h"
     16 #include "content/browser/loader/layered_resource_handler.h"
     17 #include "content/browser/loader/temporary_file_stream.h"
     18 #include "content/common/content_export.h"
     19 #include "net/url_request/url_request.h"
     20 #include "net/url_request/url_request_status.h"
     21 #include "url/gurl.h"
     22 
     23 namespace net {
     24 class FileStream;
     25 class GrowableIOBuffer;
     26 }
     27 
     28 namespace storage {
     29 class ShareableFileReference;
     30 }
     31 
     32 namespace content {
     33 
     34 // Redirects network data to a file.  This is intended to be layered in front of
     35 // either the AsyncResourceHandler or the SyncResourceHandler.  The downstream
     36 // resource handler does not see OnWillRead or OnReadCompleted calls. Instead,
     37 // the ResourceResponse contains the path to a temporary file and
     38 // OnDataDownloaded is called as the file downloads.
     39 class CONTENT_EXPORT RedirectToFileResourceHandler
     40     : public LayeredResourceHandler {
     41  public:
     42   typedef base::Callback<void(const CreateTemporaryFileStreamCallback&)>
     43       CreateTemporaryFileStreamFunction;
     44 
     45   // Create a RedirectToFileResourceHandler for |request| which wraps
     46   // |next_handler|.
     47   RedirectToFileResourceHandler(scoped_ptr<ResourceHandler> next_handler,
     48                                 net::URLRequest* request);
     49   virtual ~RedirectToFileResourceHandler();
     50 
     51   // Replace the CreateTemporaryFileStream implementation with a mocked one for
     52   // testing purposes. The function should create a net::FileStream and a
     53   // ShareableFileReference and then asynchronously pass them to the
     54   // CreateTemporaryFileStreamCallback.
     55   void SetCreateTemporaryFileStreamFunctionForTesting(
     56       const CreateTemporaryFileStreamFunction& create_temporary_file_stream);
     57 
     58   // LayeredResourceHandler implementation:
     59   virtual bool OnResponseStarted(ResourceResponse* response,
     60                                  bool* defer) OVERRIDE;
     61   virtual bool OnWillStart(const GURL& url, bool* defer) OVERRIDE;
     62   virtual bool OnWillRead(scoped_refptr<net::IOBuffer>* buf,
     63                           int* buf_size,
     64                           int min_size) OVERRIDE;
     65   virtual bool OnReadCompleted(int bytes_read, bool* defer) OVERRIDE;
     66   virtual void OnResponseCompleted(const net::URLRequestStatus& status,
     67                                    const std::string& security_info,
     68                                    bool* defer) OVERRIDE;
     69 
     70  private:
     71   void DidCreateTemporaryFile(base::File::Error error_code,
     72                               scoped_ptr<net::FileStream> file_stream,
     73                               storage::ShareableFileReference* deletable_file);
     74 
     75   // Called by RedirectToFileResourceHandler::Writer.
     76   void DidWriteToFile(int result);
     77 
     78   bool WriteMore();
     79   bool BufIsFull() const;
     80   void ResumeIfDeferred();
     81 
     82   CreateTemporaryFileStreamFunction create_temporary_file_stream_;
     83 
     84   // We allocate a single, fixed-size IO buffer (buf_) used to read from the
     85   // network (buf_write_pending_ is true while the system is copying data into
     86   // buf_), and then write this buffer out to disk (write_callback_pending_ is
     87   // true while writing to disk).  Reading from the network is suspended while
     88   // the buffer is full (BufIsFull returns true).  The write_cursor_ member
     89   // tracks the offset into buf_ that we are writing to disk.
     90 
     91   scoped_refptr<net::GrowableIOBuffer> buf_;
     92   bool buf_write_pending_;
     93   int write_cursor_;
     94 
     95   // Helper writer object which maintains references to the net::FileStream and
     96   // storage::ShareableFileReference. This is maintained separately so that,
     97   // on Windows, the temporary file isn't deleted until after it is closed.
     98   class Writer;
     99   Writer* writer_;
    100 
    101   // |next_buffer_size_| is the size of the buffer to be allocated on the next
    102   // OnWillRead() call.  We exponentially grow the size of the buffer allocated
    103   // when our owner fills our buffers. On the first OnWillRead() call, we
    104   // allocate a buffer of 32k and double it in OnReadCompleted() if the buffer
    105   // was filled, up to a maximum size of 512k.
    106   int next_buffer_size_;
    107 
    108   bool did_defer_;
    109 
    110   bool completed_during_write_;
    111   GURL will_start_url_;
    112   net::URLRequestStatus completed_status_;
    113   std::string completed_security_info_;
    114 
    115   base::WeakPtrFactory<RedirectToFileResourceHandler> weak_factory_;
    116 
    117   DISALLOW_COPY_AND_ASSIGN(RedirectToFileResourceHandler);
    118 };
    119 
    120 }  // namespace content
    121 
    122 #endif  // CONTENT_BROWSER_LOADER_REDIRECT_TO_FILE_RESOURCE_HANDLER_H_
    123