net/websockets/websocket_deflate_stream.h

   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 WebSocketDeflateParameters;
  25 class WebSocketDeflatePredictor;
  26
  27 // WebSocketDeflateStream is a WebSocketStream subclass.
  28 // WebSocketDeflateStream is for permessage-deflate WebSocket extension[1].
  29 //
  30 // WebSocketDeflateStream::ReadFrames and WriteFrames may change frame
  31 // boundary. In particular, if a control frame is placed in the middle of
  32 // data message frames, the control frame can overtake data frames.
  33 // Say there are frames df1, df2 and cf, df1 and df2 are frames of a
  34 // data message and cf is a control message frame. cf may arrive first and
  35 // data frames may follow cf.
  36 // Note that message boundary will be preserved, i.e. if the last frame of
  37 // a message m1 is read / written before the last frame of a message m2,
  38 // WebSocketDeflateStream will respect the order.
  39 //
  40 // [1]: http://tools.ietf.org/html/draft-ietf-hybi-permessage-compression-12
  41 class NET_EXPORT_PRIVATE WebSocketDeflateStream : public WebSocketStream {
  42  public:
  43   WebSocketDeflateStream(scoped_ptr<WebSocketStream> stream,
  44                          const WebSocketDeflateParameters& params,
  45                          scoped_ptr<WebSocketDeflatePredictor> predictor);
  46   ~WebSocketDeflateStream() override;
  47
  48   // WebSocketStream functions.
  49   int ReadFrames(ScopedVector<WebSocketFrame>* frames,
  50                  const CompletionCallback& callback) override;
  51   int WriteFrames(ScopedVector<WebSocketFrame>* frames,
  52                   const CompletionCallback& callback) override;
  53   void Close() override;
  54   std::string GetSubProtocol() const override;
  55   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_