Add WebSocketFrameParser.

net/websockets/websocket_frame.h

+// 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_H_
+#define NET_WEBSOCKETS_WEBSOCKET_FRAME_H_
+#pragma once
+
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/memory/ref_counted.h"
+#include "net/base/net_export.h"
+
+namespace net {
+
+// Represents a WebSocket frame header which may be shared by multiple
+// WebSocketPartialFrames.
+struct NET_EXPORT_PRIVATE WebSocketFrameHeader
+    : public base::RefCounted<WebSocketFrameHeader> {
+  typedef int OpCode;
+  static const OpCode kOpCodeContinuation;
+  static const OpCode kOpCodeText;
+  static const OpCode kOpCodeBinary;
+  static const OpCode kOpCodeClose;
+  static const OpCode kOpCodePing;
+  static const OpCode kOpCodePong;
+
+  // This value must be a compile-time constant. "enum hack" is used here
+  // to make MSVC happy.
+  enum { kMaskingKeyLength = 4 };
+
+  // Members below correspond to each item in WebSocket frame header.
+  // See <http://tools.ietf.org/html/rfc6455#section-5.2> for details.

[Takashi Toyoshima, 2012/04/04 05:46:21]

Usually, we don't use <> to refer URLs.
I could not provide grounds, but some reviewer suggested write URL directly and
if you finish a sentence with URL, insert one space before dot, e.g. See
http://crbug.com/XXXX .

[Yuta Kitamura, 2012/04/09 08:17:57]

$ git grep "<http" |wc -l
197

To my understanding, using <> to refer a URL is not so common but is actually
used in some places, and is not prohibited.

See also:
<https://groups.google.com/a/chromium.org/group/chromium-dev/browse_thread/thr...>

I think the conclusion of this thread is that (to my understanding): comments in
source code are free-form text and there is no particular mandatory rules about
the contents of comments.

[Yuta Kitamura, 2012/04/09 12:12:26]

Counted the number of instances of "one space before dot" notation:

$ git grep 'http.\+ \.' |wc -l
127
(Note: this count is somewhat overestimated as the result includes many false
hits)

Coming to look at this, I think "one space before dot" notation is not so common
either.

+  bool final;
+  bool reserved1;
+  bool reserved2;
+  bool reserved3;
+  OpCode opcode;
+  bool masked;
+  uint64 payload_length;
+};
+
+// Contains payload data of a WebSocket frame.
+//
+// Payload of a WebSocket frame may be divided into multiple
+// WebSocketPartialFrame objects. You need to look at |final_part| member
+// variable to detect the end of a series of partial frame objects.
+//
+// Frame dissection is necessary to handle WebSocket frame stream containing
+// abritrarily large frames in the browser process. Because the server may send
+// a huge frame that doesn't fit in the memory, we cannot store the entire
+// payload data in the memory.
+//
+// Users of this struct should treat WebSocket frames as a data stream; it's
+// important to keep the frame data flowing, especially in the browser.
+// Do not let the data stuck somewhere in the pipeline.
+struct NET_EXPORT_PRIVATE WebSocketPartialFrame {
+  WebSocketPartialFrame();
+  ~WebSocketPartialFrame();
+
+  // |header| may be shared among multiple WebSocketPartialFrames.
+  scoped_refptr<const WebSocketFrameHeader> header;
+
+  // Indicates this part is the last of partial frames.
+  bool final_part;
+
+  // |data| is always unmasked even if the frame is masked.
+  std::vector<char> data;
+};
+
+}  // namespace net
+
+#endif  // NET_WEBSOCKETS_WEBSOCKET_FRAME_H_