Add WebSocketError to indicate decoding failure reason

net/websockets/websocket_frame_parser.cc

 // 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.
 
 #include "net/websockets/websocket_frame_parser.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "base/basictypes.h"
@@ skipping 18 matching lines @@
 const uint64 kPayloadLengthWithTwoByteExtendedLengthField = 126;
 const uint64 kPayloadLengthWithEightByteExtendedLengthField = 127;
 
 }  // Unnamed namespace.
 
 namespace net {
 
 WebSocketFrameParser::WebSocketFrameParser()
     : current_read_pos_(0),
       frame_offset_(0),
-      failed_(false) {
+      failed_(false),
+      error_code_(WS_OK) {
   std::fill(masking_key_,
             masking_key_ + WebSocketFrameHeader::kMaskingKeyLength,
             '\0');
 }
 
 WebSocketFrameParser::~WebSocketFrameParser() {
 }
 
 bool WebSocketFrameParser::Decode(
     const char* data,
@@ skipping 64 matching lines @@
   uint8 second_byte = *current++;
 
   bool final = (first_byte & kFinalBit) != 0;
   bool reserved1 = (first_byte & kReserved1Bit) != 0;
   bool reserved2 = (first_byte & kReserved2Bit) != 0;
   bool reserved3 = (first_byte & kReserved3Bit) != 0;
   OpCode opcode = first_byte & kOpCodeMask;
 
   bool masked = (second_byte & kMaskBit) != 0;
   uint64 payload_length = second_byte & kPayloadLengthMask;
-  bool valid_length_format = true;
-  bool message_too_big = false;
   if (payload_length == kPayloadLengthWithTwoByteExtendedLengthField) {
     if (end - current < 2)
       return;
     uint16 payload_length_16;
     ReadBigEndian(current, &payload_length_16);
     current += 2;
     payload_length = payload_length_16;
     if (payload_length <= kMaxPayloadLengthWithoutExtendedLengthField)
-      valid_length_format = false;
+      error_code_ = WS_ERR_PROTOCOL_ERROR;
   } else if (payload_length == kPayloadLengthWithEightByteExtendedLengthField) {
     if (end - current < 8)
       return;
     ReadBigEndian(current, &payload_length);
     current += 8;
     if (payload_length <= kuint16max ||
-        payload_length > static_cast<uint64>(kint64max)) {
-      valid_length_format = false;
-    }
-    if (payload_length > static_cast<uint64>(kint32max))
-      message_too_big = true;
+        payload_length > static_cast<uint64>(kint64max))

[mmenke, 2012/08/01 14:44:59]

nit:  Google style (Or maybe Chrome style, can't remember which) is to use
braces when the conditional takes more than one line.

+      error_code_ = WS_ERR_PROTOCOL_ERROR;
+    else if (payload_length > static_cast<uint64>(kint32max))
+      error_code_ = WS_ERR_MESSAGE_TOO_BIG;
   }
-  if (!valid_length_format || message_too_big) {
+  if (error_code_ != WS_OK) {
     failed_ = true;
     buffer_.clear();
     current_read_pos_ = 0;
     current_frame_header_.reset();
     frame_offset_ = 0;
     return;
   }
 
   if (masked) {
     if (end - current < kMaskingKeyLength)
@@ skipping 57 matching lines @@
   if (frame_offset_ == current_frame_header_->payload_length) {
     frame_chunk->final_chunk = true;
     current_frame_header_.reset();
     frame_offset_ = 0;
   }
 
   return frame_chunk.Pass();
 }
 
 }  // namespace net