HTTP retry support.

net/http/http_network_transaction.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_HTTP_HTTP_NETWORK_TRANSACTION_H_
 #define NET_HTTP_HTTP_NETWORK_TRANSACTION_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 172 matching lines @@
   int DoDrainBodyForAuthRestartComplete(int result);
 
   void BuildRequestHeaders(bool using_proxy);
 
   // Record histogram of time until first byte of header is received.
   void LogTransactionConnectedMetrics();
 
   // Record histogram of latency (durations until last byte received).
   void LogTransactionMetrics() const;
 
+  // Record histogram of retry attempt success rate.
+  void LogTransactionRetryMetrics(int error) const;
+
   // Writes a log message to help debugging in the field when we block a proxy
   // response to a CONNECT request.
   void LogBlockedTunnelResponse(int response_code) const;
 
   // Called to handle a client certificate request.
   int HandleCertificateRequest(int error);
 
   // Called to possibly handle a client authentication error.
   void HandleClientAuthError(int error);
 
@@ skipping 106 matching lines @@
   // page just a few hundred bytes long.
   static const int kDrainBodyBufferSize = 1024;
 
   // User buffer and length passed to the Read method.
   scoped_refptr<IOBuffer> read_buf_;
   int read_buf_len_;
 
   // Total number of bytes received on streams for this transaction.
   int64 total_received_bytes_;
 
+  // Total number of retries for this transaction.
+  int retry_attempt_;
+
+  // How much data was read from a response body before retrying a transaction.
+  int64 offset_;
+
+  // Previous content length, used for retry.
+  int64 previous_content_length_;
+
+  // Previous etag, used for retry.
+  std::string previous_etag_;
+
+  // Previous last modified, used for retry.
+  std::string previous_last_modified_;
+
+  // Hash of previous request attempt for cross-checking when retrying without
+  // range support.
+  uint8 hash_[8];
+
   // The time the Start method was called.
   base::Time start_time_;
 
   // When the transaction started / finished sending the request, including
   // the body, if present.
   base::TimeTicks send_start_time_;
   base::TimeTicks send_end_time_;
 
   // The next state in the state machine.
   State next_state_;
 
   // True when the tunnel is in the process of being established - we can't
   // read from the socket until the tunnel is done.
   bool establishing_tunnel_;
 
   // The helper object to use to create WebSocketHandshakeStreamBase
   // objects. Only relevant when establishing a WebSocket connection.
   WebSocketHandshakeStreamBase::CreateHelper*
       websocket_handshake_stream_base_create_helper_;
 
   BeforeNetworkStartCallback before_network_start_callback_;
   BeforeProxyHeadersSentCallback before_proxy_headers_sent_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(HttpNetworkTransaction);
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_NETWORK_TRANSACTION_H_