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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | |
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_FRAME_PARSER_H_ | |
6 #define NET_WEBSOCKETS_WEBSOCKET_FRAME_PARSER_H_ | |
7 | |
8 #include <vector> | |
9 | |
10 #include "base/basictypes.h" | |
11 #include "base/memory/ref_counted.h" | |
12 #include "base/memory/scoped_ptr.h" | |
13 #include "base/memory/scoped_vector.h" | |
14 #include "net/base/net_export.h" | |
15 #include "net/websockets/websocket_errors.h" | |
16 #include "net/websockets/websocket_frame.h" | |
17 | |
18 namespace net { | |
19 | |
20 // Parses WebSocket frames from byte stream. | |
21 // | |
22 // Specification of WebSocket frame format is available at | |
23 // <http://tools.ietf.org/html/rfc6455#section-5>. | |
24 | |
25 class NET_EXPORT WebSocketFrameParser { | |
26 public: | |
27 WebSocketFrameParser(); | |
28 ~WebSocketFrameParser(); | |
29 | |
30 // Decodes the given byte stream and stores parsed WebSocket frames in | |
31 // |frame_chunks|. | |
32 // | |
33 // If the parser encounters invalid payload length format, Decode() fails | |
34 // and returns false. Once Decode() has failed, the parser refuses to decode | |
35 // any more data and future invocations of Decode() will simply return false. | |
36 // | |
37 // Payload data of parsed WebSocket frames may be incomplete; see comments in | |
38 // websocket_frame.h for more details. | |
39 bool Decode(const char* data, | |
40 size_t length, | |
41 ScopedVector<WebSocketFrameChunk>* frame_chunks); | |
42 | |
43 // Returns kWebSocketNormalClosure if the parser has not failed to decode | |
44 // WebSocket frames. Otherwise returns WebSocketError which is defined in | |
45 // websocket_errors.h. We can convert net::WebSocketError to net::Error by | |
46 // using WebSocketErrorToNetError(). | |
47 WebSocketError websocket_error() const { return websocket_error_; } | |
48 | |
49 private: | |
50 // Tries to decode a frame header from |current_read_pos_|. | |
51 // If successful, this function updates |current_read_pos_|, | |
52 // |current_frame_header_|, and |masking_key_| (if available). | |
53 // This function may set |failed_| to true if it observes a corrupt frame. | |
54 // If there is not enough data in the remaining buffer to parse a frame | |
55 // header, this function returns without doing anything. | |
56 void DecodeFrameHeader(); | |
57 | |
58 // Decodes frame payload and creates a WebSocketFrameChunk object. | |
59 // This function updates |current_read_pos_| and |frame_offset_| after | |
60 // parsing. This function returns a frame object even if no payload data is | |
61 // available at this moment, so the receiver could make use of frame header | |
62 // information. If the end of frame is reached, this function clears | |
63 // |current_frame_header_|, |frame_offset_| and |masking_key_|. | |
64 scoped_ptr<WebSocketFrameChunk> DecodeFramePayload(bool first_chunk); | |
65 | |
66 // Internal buffer to store the data to parse. | |
67 std::vector<char> buffer_; | |
68 | |
69 // Position in |buffer_| where the next round of parsing starts. | |
70 size_t current_read_pos_; | |
71 | |
72 // Frame header and masking key of the current frame. | |
73 // |masking_key_| is filled with zeros if the current frame is not masked. | |
74 scoped_ptr<WebSocketFrameHeader> current_frame_header_; | |
75 WebSocketMaskingKey masking_key_; | |
76 | |
77 // Amount of payload data read so far for the current frame. | |
78 uint64 frame_offset_; | |
79 | |
80 WebSocketError websocket_error_; | |
81 | |
82 DISALLOW_COPY_AND_ASSIGN(WebSocketFrameParser); | |
83 }; | |
84 | |
85 } // namespace net | |
86 | |
87 #endif // NET_WEBSOCKETS_WEBSOCKET_FRAME_PARSER_H_ | |
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