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      1 // Copyright 2013 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 NET_WEBSOCKETS_WEBSOCKET_DEFLATE_STREAM_H_
      6 #define NET_WEBSOCKETS_WEBSOCKET_DEFLATE_STREAM_H_
      7 
      8 #include <string>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/scoped_ptr.h"
     12 #include "base/memory/scoped_vector.h"
     13 #include "net/base/completion_callback.h"
     14 #include "net/base/net_export.h"
     15 #include "net/websockets/websocket_deflater.h"
     16 #include "net/websockets/websocket_frame.h"
     17 #include "net/websockets/websocket_inflater.h"
     18 #include "net/websockets/websocket_stream.h"
     19 
     20 class GURL;
     21 
     22 namespace net {
     23 
     24 class WebSocketDeflatePredictor;
     25 
     26 // WebSocketDeflateStream is a WebSocketStream subclass.
     27 // WebSocketDeflateStream is for permessage-deflate WebSocket extension[1].
     28 //
     29 // WebSocketDeflateStream::ReadFrames and WriteFrames may change frame
     30 // boundary. In particular, if a control frame is placed in the middle of
     31 // data message frames, the control frame can overtake data frames.
     32 // Say there are frames df1, df2 and cf, df1 and df2 are frames of a
     33 // data message and cf is a control message frame. cf may arrive first and
     34 // data frames may follow cf.
     35 // Note that message boundary will be preserved, i.e. if the last frame of
     36 // a message m1 is read / written before the last frame of a message m2,
     37 // WebSocketDeflateStream will respect the order.
     38 //
     39 // [1]: http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-12
     40 class NET_EXPORT_PRIVATE WebSocketDeflateStream : public WebSocketStream {
     41  public:
     42   WebSocketDeflateStream(scoped_ptr<WebSocketStream> stream,
     43                          WebSocketDeflater::ContextTakeOverMode mode,
     44                          int client_window_bits,
     45                          scoped_ptr<WebSocketDeflatePredictor> predictor);
     46   virtual ~WebSocketDeflateStream();
     47 
     48   // WebSocketStream functions.
     49   virtual int ReadFrames(ScopedVector<WebSocketFrame>* frames,
     50                          const CompletionCallback& callback) OVERRIDE;
     51   virtual int WriteFrames(ScopedVector<WebSocketFrame>* frames,
     52                           const CompletionCallback& callback) OVERRIDE;
     53   virtual void Close() OVERRIDE;
     54   virtual std::string GetSubProtocol() const OVERRIDE;
     55   virtual std::string GetExtensions() const OVERRIDE;
     56 
     57  private:
     58   enum ReadingState {
     59     READING_COMPRESSED_MESSAGE,
     60     READING_UNCOMPRESSED_MESSAGE,
     61     NOT_READING,
     62   };
     63 
     64   enum WritingState {
     65     WRITING_COMPRESSED_MESSAGE,
     66     WRITING_UNCOMPRESSED_MESSAGE,
     67     WRITING_POSSIBLY_COMPRESSED_MESSAGE,
     68     NOT_WRITING,
     69   };
     70 
     71   // Handles asynchronous completion of ReadFrames() call on |stream_|.
     72   void OnReadComplete(ScopedVector<WebSocketFrame>* frames,
     73                       const CompletionCallback& callback,
     74                       int result);
     75 
     76   // This function deflates |frames| and stores the result to |frames| itself.
     77   int Deflate(ScopedVector<WebSocketFrame>* frames);
     78   void OnMessageStart(const ScopedVector<WebSocketFrame>& frames, size_t index);
     79   int AppendCompressedFrame(const WebSocketFrameHeader& header,
     80                             ScopedVector<WebSocketFrame>* frames_to_write);
     81   int AppendPossiblyCompressedMessage(
     82       ScopedVector<WebSocketFrame>* frames,
     83       ScopedVector<WebSocketFrame>* frames_to_write);
     84 
     85   // This function inflates |frames| and stores the result to |frames| itself.
     86   int Inflate(ScopedVector<WebSocketFrame>* frames);
     87 
     88   int InflateAndReadIfNecessary(ScopedVector<WebSocketFrame>* frames,
     89                                 const CompletionCallback& callback);
     90 
     91   const scoped_ptr<WebSocketStream> stream_;
     92   WebSocketDeflater deflater_;
     93   WebSocketInflater inflater_;
     94   ReadingState reading_state_;
     95   WritingState writing_state_;
     96   WebSocketFrameHeader::OpCode current_reading_opcode_;
     97   WebSocketFrameHeader::OpCode current_writing_opcode_;
     98   scoped_ptr<WebSocketDeflatePredictor> predictor_;
     99 
    100   DISALLOW_COPY_AND_ASSIGN(WebSocketDeflateStream);
    101 };
    102 
    103 }  // namespace net
    104 
    105 #endif  // NET_WEBSOCKETS_WEBSOCKET_DEFLATE_STREAM_H_
    106