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- // Copyright (c) 2012 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_FRAME_PARSER_H_
- #define NET_WEBSOCKETS_WEBSOCKET_FRAME_PARSER_H_
- #include <stddef.h>
- #include <stdint.h>
- #include <memory>
- #include <vector>
- #include "base/containers/span.h"
- #include "net/base/net_export.h"
- #include "net/websockets/websocket_errors.h"
- #include "net/websockets/websocket_frame.h"
- namespace net {
- // Parses WebSocket frames from byte stream.
- //
- // Specification of WebSocket frame format is available at
- // <http://tools.ietf.org/html/rfc6455#section-5>.
- // This class does *NOT* unmask frame payload.
- class NET_EXPORT WebSocketFrameParser {
- public:
- WebSocketFrameParser();
- WebSocketFrameParser(const WebSocketFrameParser&) = delete;
- WebSocketFrameParser& operator=(const WebSocketFrameParser&) = delete;
- ~WebSocketFrameParser();
- // Decodes the given byte stream and stores parsed WebSocket frames in
- // |frame_chunks|.
- // Each WebSocketFrameChunk's payload is a subspan of [data, data + length).
- // Thus callers must take care of its lifecycle.
- //
- // If the parser encounters invalid payload length format, Decode() fails
- // and returns false. Once Decode() has failed, the parser refuses to decode
- // any more data and future invocations of Decode() will simply return false.
- //
- // Payload data of parsed WebSocket frames may be incomplete; see comments in
- // websocket_frame.h for more details.
- bool Decode(const char* data,
- size_t length,
- std::vector<std::unique_ptr<WebSocketFrameChunk>>* frame_chunks);
- // Returns kWebSocketNormalClosure if the parser has not failed to decode
- // WebSocket frames. Otherwise returns WebSocketError which is defined in
- // websocket_errors.h. We can convert net::WebSocketError to net::Error by
- // using WebSocketErrorToNetError().
- WebSocketError websocket_error() const { return websocket_error_; }
- private:
- // Tries to decode a frame header from |data|.
- // If successful, this function updates
- // |current_frame_header_|, and |masking_key_| (if available) and returns
- // the number of consumed bytes in |data|.
- // If there is not enough data in the remaining buffer to parse a frame
- // header, this function returns 0 without doing anything.
- // This function may update |websocket_error_| if it observes a corrupt frame.
- size_t DecodeFrameHeader(base::span<const char> data);
- // Decodes frame payload and creates a WebSocketFrameChunk object.
- // This function updates |frame_offset_| after
- // parsing. This function returns a frame object even if no payload data is
- // available at this moment, so the receiver could make use of frame header
- // information. If the end of frame is reached, this function clears
- // |current_frame_header_|, |frame_offset_| and |masking_key_|.
- std::unique_ptr<WebSocketFrameChunk> DecodeFramePayload(
- bool first_chunk,
- base::span<const char>* data);
- // Internal buffer to store the data to parse header.
- std::vector<char> incomplete_header_buffer_;
- // Frame header and masking key of the current frame.
- // |masking_key_| is filled with zeros if the current frame is not masked.
- std::unique_ptr<WebSocketFrameHeader> current_frame_header_;
- // Amount of payload data read so far for the current frame.
- uint64_t frame_offset_ = 0;
- WebSocketError websocket_error_ = kWebSocketNormalClosure;
- };
- } // namespace net
- #endif // NET_WEBSOCKETS_WEBSOCKET_FRAME_PARSER_H_
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