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// Copyright 2014 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_SPDY_HPACK_DECODER_H_
#define NET_SPDY_HPACK_DECODER_H_
#include <map>
#include <string>
#include <vector>
#include "base/basictypes.h"
#include "base/macros.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/spdy/hpack_header_table.h"
#include "net/spdy/hpack_input_stream.h"
#include "net/spdy/spdy_protocol.h"
// An HpackDecoder decodes header sets as outlined in
// http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-08
namespace net {
class HpackHuffmanTable;
namespace test {
class HpackDecoderPeer;
} // namespace test
class NET_EXPORT_PRIVATE HpackDecoder {
public:
friend class test::HpackDecoderPeer;
// |table| is an initialized HPACK Huffman table, having an
// externally-managed lifetime which spans beyond HpackDecoder.
explicit HpackDecoder(const HpackHuffmanTable& table);
~HpackDecoder();
// Called upon acknowledgement of SETTINGS_HEADER_TABLE_SIZE.
void ApplyHeaderTableSizeSetting(size_t size_setting) {
header_table_.SetSettingsHeaderTableSize(size_setting);
}
// Called as headers data arrives. Returns false if an error occurred.
// TODO(jgraettinger): A future version of this method will incrementally
// parse and deliver headers via SpdyHeadersHandlerInterface. For now,
// header data is buffered until HandleControlFrameHeadersComplete().
bool HandleControlFrameHeadersData(SpdyStreamId stream_id,
const char* headers_data,
size_t headers_data_length);
// Called after a headers block has been completely delivered via
// HandleControlFrameHeadersData(). Returns false if an error occurred.
// TODO(jgraettinger): A future version of this method will simply deliver
// the Cookie header (which has been incrementally reconstructed) and notify
// the visitor that the block is finished. For now, this method decodes the
// complete buffered block, and stores results to |decoded_block_|.
bool HandleControlFrameHeadersComplete(SpdyStreamId stream_id);
// Accessor for the most recently decoded headers block. Valid until the next
// call to HandleControlFrameHeadersData().
// TODO(jgraettinger): This was added to facilitate re-encoding the block in
// SPDY3 format for delivery to the SpdyFramer visitor, and will be removed
// with the migration to SpdyHeadersHandlerInterface.
const std::map<std::string, std::string>& decoded_block() {
return decoded_block_;
}
private:
// Adds the header representation to |decoded_block_|, applying the
// following rules, as per sections 8.1.3.3 & 8.1.3.4 of the HTTP2 draft
// specification:
// - Multiple values of the Cookie header are joined, delmited by '; '.
// This reconstruction is required to properly handle Cookie crumbling.
// - Multiple values of other headers are joined and delimited by '\0'.
// Note that this may be too accomodating, as the sender's HTTP2 layer
// should have already joined and delimited these values.
//
// Returns false if a pseudo-header field follows a regular header one, which
// MUST be treated as malformed, as per sections 8.1.2.1. of the HTTP2 draft
// specification.
//
// TODO(jgraettinger): This method will eventually emit to the
// SpdyHeadersHandlerInterface visitor.
bool HandleHeaderRepresentation(base::StringPiece name,
base::StringPiece value);
const uint32 max_string_literal_size_;
HpackHeaderTable header_table_;
// Incrementally reconstructed cookie value.
std::string cookie_value_;
// TODO(jgraettinger): Buffer for headers data, and storage for the last-
// processed headers block. Both will be removed with the switch to
// SpdyHeadersHandlerInterface.
std::string headers_block_buffer_;
std::map<std::string, std::string> decoded_block_;
// Flag to keep track of having seen a regular header field.
bool regular_header_seen_;
// Huffman table to be applied to decoded Huffman literals,
// and scratch space for storing those decoded literals.
const HpackHuffmanTable& huffman_table_;
std::string key_buffer_, value_buffer_;
// Handlers for decoding HPACK opcodes and header representations
// (or parts thereof). These methods return true on success and
// false on error.
bool DecodeNextOpcode(HpackInputStream* input_stream);
bool DecodeNextHeaderTableSizeUpdate(HpackInputStream* input_stream);
bool DecodeNextIndexedHeader(HpackInputStream* input_stream);
bool DecodeNextLiteralHeader(HpackInputStream* input_stream,
bool should_index);
bool DecodeNextName(HpackInputStream* input_stream,
base::StringPiece* next_name);
bool DecodeNextStringLiteral(HpackInputStream* input_stream,
bool is_header_key, // As distinct from a value.
base::StringPiece* output);
DISALLOW_COPY_AND_ASSIGN(HpackDecoder);
};
} // namespace net
#endif // NET_SPDY_HPACK_DECODER_H_
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