// 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_SPDY_HEADERS_BLOCK_PARSER_H_
#define NET_SPDY_SPDY_HEADERS_BLOCK_PARSER_H_
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/strings/string_piece.h"
#include "net/base/net_export.h"
#include "net/spdy/spdy_prefixed_buffer_reader.h"
#include "net/spdy/spdy_protocol.h"
namespace net {
// A handler class for SPDY headers.
class SpdyHeadersHandlerInterface {
public:
virtual ~SpdyHeadersHandlerInterface() {}
// A callback method which notifies when the parser starts handling a new
// SPDY headers block, this method also notifies on the number of headers in
// the block.
virtual void OnHeaderBlock(SpdyStreamId stream_id,
uint32_t num_of_headers) = 0;
// A callback method which notifies on a SPDY header key value pair.
virtual void OnHeader(SpdyStreamId stream_id,
base::StringPiece key,
base::StringPiece value) = 0;
// A callback method which notifies when the parser finishes handling a SPDY
// headers block.
virtual void OnHeaderBlockEnd(SpdyStreamId stream_id) = 0;
};
namespace test {
class SpdyHeadersBlockParserPeer;
} // namespace test
// This class handles SPDY headers block bytes and parses out key-value pairs
// as they arrive. This class is not thread-safe, and assumes that all headers
// block bytes are processed in a single thread.
class NET_EXPORT_PRIVATE SpdyHeadersBlockParser {
public:
// Bound on acceptable header name or value length.
static const size_t kMaximumFieldLength; // = 16 * 1024
// Constructor. The handler's OnHeader will be called for every key
// value pair that we parsed from the headers block.
SpdyHeadersBlockParser(SpdyMajorVersion spdy_version,
SpdyHeadersHandlerInterface* handler);
virtual ~SpdyHeadersBlockParser();
// Handles headers block data as it arrives. Returns false if an error has
// been set, which can include the recoverable error NEED_MORE_DATA. Returns
// true if the invocation completes the parse of the entire headers block,
// in which case the parser is ready for a new headers block.
bool HandleControlFrameHeadersData(SpdyStreamId stream_id,
const char* headers_data,
size_t len);
enum ParserError {
OK,
// Set when parsing failed due to insufficient data.
// This error is recoverable, by passing in new data.
NEED_MORE_DATA,
// Set when a complete block has been read, but unprocessed data remains.
TOO_MUCH_DATA,
// Set when a block exceeds |MaxNumberOfHeadersForVersion| headers.
HEADER_BLOCK_TOO_LARGE,
// Set when a header key or value exceeds |kMaximumFieldLength|.
HEADER_FIELD_TOO_LARGE,
};
ParserError get_error() const { return error_; }
// Resets the state of the parser to prepare it for a headers block of a
// new frame.
void Reset();
// Returns the size in bytes of a length field in a SPDY header.
static size_t LengthFieldSizeForVersion(SpdyMajorVersion spdy_version);
// Returns the maximal number of headers in a SPDY headers block.
static size_t MaxNumberOfHeadersForVersion(SpdyMajorVersion spdy_version);
private:
typedef SpdyPrefixedBufferReader Reader;
// Parses and sanity-checks header block length.
void ParseBlockLength(Reader* reader);
// Parses and sanity-checks header field length.
void ParseFieldLength(Reader* reader);
// Parses and decodes network-order lengths into |parsed_length|.
void ParseLength(Reader* reader, uint32_t* parsed_length);
// The state of the parser.
enum ParserState {
READING_HEADER_BLOCK_LEN,
READING_KEY_LEN,
READING_KEY,
READING_VALUE_LEN,
READING_VALUE,
FINISHED_HEADER
};
ParserState state_;
// Size in bytes of a length field in the spdy header.
const size_t length_field_size_;
// The maximal number of headers in a SPDY headers block.
const size_t max_headers_in_block_;
// Number of key-value pairs until we complete handling the current
// headers block.
uint32_t remaining_key_value_pairs_for_frame_;
// The length of the next header field to be read (either key or value).
uint32_t next_field_length_;
// Handles key-value pairs as we parse them.
SpdyHeadersHandlerInterface* handler_;
// Holds unprocessed buffer remainders between calls to
// |HandleControlFrameHeadersData|.
SpdyPinnableBufferPiece headers_block_prefix_;
// Holds the key of a partially processed header between calls to
// |HandleControlFrameHeadersData|.
SpdyPinnableBufferPiece key_;
// The current header block stream identifier.
SpdyStreamId stream_id_;
ParserError error_;
};
} // namespace net
#endif // NET_SPDY_SPDY_HEADERS_BLOCK_PARSER_H_