1 // Copyright 2013 The Chromium Authors 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 <stddef.h> 9 10 #include <memory> 11 #include <vector> 12 13 #include "net/base/net_export.h" 14 15 namespace net { 16 17 struct WebSocketFrame; 18 19 // WebSocketDeflatePredictor is an interface class used for judging whether 20 // a WebSocketDeflateStream should compress a message or not. 21 class NET_EXPORT_PRIVATE WebSocketDeflatePredictor { 22 public: 23 enum Result { 24 // Deflate and send the message. 25 DEFLATE, 26 // Do not deflate and send the original message. 27 DO_NOT_DEFLATE, 28 // Try compressing the message and send the smaller one of the original 29 // and the compressed message. 30 // Returning this result implies that the deflater is running on 31 // DoNotTakeOverContext mode and the entire message is visible. 32 TRY_DEFLATE, 33 }; 34 35 virtual ~WebSocketDeflatePredictor() = default; 36 37 // Predicts and returns whether the deflater should deflate the message 38 // which begins with |frames[frame_index]| or not. 39 // |frames[(frame_index + 1):]| consists of future frames if any. 40 // |frames[frame_index]| must be the first frame of a data message, 41 // but future frames may contain control message frames. 42 // |frames[frame_index]| cannot be recorded yet and all preceding 43 // data frames have to be already recorded when this method is called. 44 virtual Result Predict( 45 const std::vector<std::unique_ptr<WebSocketFrame>>& frames, 46 size_t frame_index) = 0; 47 48 // Records frame data for future prediction. 49 // Only data frames should be recorded. Do not pass control frames' data. 50 // All input data frames for the stream must be recorded in order. 51 virtual void RecordInputDataFrame(const WebSocketFrame* frame) = 0; 52 53 // Records frame data for future prediction. 54 // Only data frames should be recorded. Do not pass control frames' data. 55 // All data frames written by the stream must be recorded in order 56 // regardless of whether they are compressed or not. 57 virtual void RecordWrittenDataFrame(const WebSocketFrame* frame) = 0; 58 }; 59 60 } // namespace net 61 62 #endif // NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_ 63