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_PREDICTOR_H_ 6 #define NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_ 7 8 #include "base/basictypes.h" 9 #include "base/memory/scoped_vector.h" 10 #include "net/base/net_export.h" 11 12 namespace net { 13 14 struct WebSocketFrame; 15 16 // WebSocketDeflatePredictor is an interface class used for judging whether 17 // a WebSocketDeflateStream should compress a message or not. 18 class NET_EXPORT_PRIVATE WebSocketDeflatePredictor { 19 public: 20 enum Result { 21 // Deflate and send the message. 22 DEFLATE, 23 // Do not deflate and send the original message. 24 DO_NOT_DEFLATE, 25 // Try compressing the message and send the smaller one of the original 26 // and the compressed message. 27 // Returning this result implies that the deflater is running on 28 // DoNotTakeOverContext mode and the entire message is visible. 29 TRY_DEFLATE, 30 }; 31 32 virtual ~WebSocketDeflatePredictor() {} 33 34 // Predicts and returns whether the deflater should deflate the message 35 // which begins with |frames[frame_index]| or not. 36 // |frames[(frame_index + 1):]| consists of future frames if any. 37 // |frames[frame_index]| must be the first frame of a data message, 38 // but future frames may contain control message frames. 39 // |frames[frame_index]| cannot be recorded yet and all preceding 40 // data frames have to be already recorded when this method is called. 41 virtual Result Predict(const ScopedVector<WebSocketFrame>& frames, 42 size_t frame_index) = 0; 43 44 // Records frame data for future prediction. 45 // Only data frames should be recorded. Do not pass control frames' data. 46 // All input data frames for the stream must be recorded in order. 47 virtual void RecordInputDataFrame(const WebSocketFrame* frame) = 0; 48 49 // Records frame data for future prediction. 50 // Only data frames should be recorded. Do not pass control frames' data. 51 // All data frames written by the stream must be recorded in order 52 // regardless of whether they are compressed or not. 53 virtual void RecordWrittenDataFrame(const WebSocketFrame* frame) = 0; 54 }; 55 56 } // namespace net 57 58 #endif // NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_ 59
