HttpCache::Transaction layer allowing parallel validation

net/http/http_transaction.h

 // Copyright (c) 2011 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_TRANSACTION_H_
 #define NET_HTTP_HTTP_TRANSACTION_H_
 
 #include <stdint.h>
 
 #include "net/base/completion_callback.h"
@@ skipping 36 matching lines @@
                               HttpRequestHeaders* request_headers)>
       BeforeHeadersSentCallback;
 
   // Stops any pending IO and destroys the transaction object.
   virtual ~HttpTransaction() {}
 
   // Starts the HTTP transaction (i.e., sends the HTTP request).
   //
   // The consumer should ensure that request_info points to a valid value till
   // final response headers are received; after that point, the HttpTransaction
-  // will not access |*request_info| and it may be deleted.
+  // will not access |*request_info| and it may be deleted. Note that in case of
+  // range requests response headers may be received multiple times and the
+  // HttpTransaction might access |*request_info| in all of those.
   //
   // Returns OK if the transaction could be started synchronously, which means
   // that the request was served from the cache.  ERR_IO_PENDING is returned to
   // indicate that the CompletionCallback will be notified once response info is
   // available or if an IO error occurs.  Any other return value indicates that
   // the transaction could not be started.
   //
   // Regardless of the return value, the caller is expected to keep the
   // request_info object alive until Destroy is called on the transaction.
   //
@@ skipping 124 matching lines @@
 
   // Resumes the transaction after being deferred.
   virtual int ResumeNetworkStart() = 0;
 
   virtual void GetConnectionAttempts(ConnectionAttempts* out) const = 0;
 };
 
 }  // namespace net
 
 #endif  // NET_HTTP_HTTP_TRANSACTION_H_