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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_
#define NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_
#include "base/basictypes.h"
#include "base/memory/scoped_vector.h"
#include "net/base/net_export.h"
namespace net {
struct WebSocketFrame;
// WebSocketDeflatePredictor is an interface class used for judging whether
// a WebSocketDeflateStream should compress a message or not.
class NET_EXPORT_PRIVATE WebSocketDeflatePredictor {
public:
enum Result {
// Deflate and send the message.
DEFLATE,
// Do not deflate and send the original message.
DO_NOT_DEFLATE,
// Try compressing the message and send the smaller one of the original
// and the compressed message.
// Returning this result implies that the deflater is running on
// DoNotTakeOverContext mode and the entire message is visible.
TRY_DEFLATE,
};
virtual ~WebSocketDeflatePredictor() {}
// Predicts and returns whether the deflater should deflate the message
// which begins with |frames[frame_index]| or not.
// |frames[(frame_index + 1):]| consists of future frames if any.
// |frames[frame_index]| must be the first frame of a data message,
// but future frames may contain control message frames.
// |frames[frame_index]| cannot be recorded yet and all preceding
// data frames have to be already recorded when this method is called.
virtual Result Predict(const ScopedVector<WebSocketFrame>& frames,
size_t frame_index) = 0;
// Records frame data for future prediction.
// Only data frames should be recorded. Do not pass control frames' data.
// All input data frames for the stream must be recorded in order.
virtual void RecordInputDataFrame(const WebSocketFrame* frame) = 0;
// Records frame data for future prediction.
// Only data frames should be recorded. Do not pass control frames' data.
// All data frames written by the stream must be recorded in order
// regardless of whether they are compressed or not.
virtual void RecordWrittenDataFrame(const WebSocketFrame* frame) = 0;
};
} // namespace net
#endif // NET_WEBSOCKETS_WEBSOCKET_DEFLATE_PREDICTOR_H_