Simplify the the logic for setting the final response status for a

net/quic/chromium/quic_http_stream.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_QUIC_CHROMIUM_QUIC_HTTP_STREAM_H_
 #define NET_QUIC_CHROMIUM_QUIC_HTTP_STREAM_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 116 matching lines @@
   int DoSendBody();
   int DoSendBodyComplete(int rv);
 
   int ProcessResponseHeaders(const SpdyHeaderBlock& headers);
 
   int ReadAvailableData(IOBuffer* buf, int buf_len);
   void EnterStateSendHeaders();
 
   void ResetStream();
 
+  // If |has_response_status_| is false, sets |response_status| to the result
+  // of ComputeResponseStatus(). Returns |response_status_|.
+  int GetResponseStatus();

[Buck, 2017/03/28 21:19:57]

There seem to be instances where the return value of GetResponseStatus is
deliberately ignored.    So the intent there is to make sure that
SetResponseStatus(ComputeResponseStatus()) is invoked.

I wonder if it would be cleaner to wrap the latter in a new method something
like :'void UpdateResponseStatus()'?

[Ryan Hamilton, 2017/03/28 21:54:03]

Good idea. I thought about that but couldn't decide if I liked it. But since you
do, I'm sold! :)

+  // Sets |response_status_| to |response_status| and sets
+  // |has_response_status_| to true.
+  void SetResponseStatus(int response_status);
+  // Computes the correct response status based on the status of the handshake,
+  // |session_error|, |connection_error| and |stream_error|.
+  int ComputeResponseStatus() const;
+
   State next_state_;
 
   base::WeakPtr<QuicChromiumClientSession> session_;
   QuicVersion quic_version_;
   int session_error_;             // Error code from the connection shutdown.
   bool was_handshake_confirmed_;  // True if the crypto handshake succeeded.
   QuicChromiumClientSession::StreamRequest stream_request_;
   QuicChromiumClientStream* stream_;  // Non-owning.
 
   // The following three fields are all owned by the caller and must
   // outlive this object, according to the HttpStream contract.
 
   // The request to send.
   // Only valid before the response body is read.
   const HttpRequestInfo* request_info_;
 
   // The request body to send, if any, owned by the caller.
   UploadDataStream* request_body_stream_;
   // Time the request was issued.
   base::Time request_time_;
   // The priority of the request.
   RequestPriority priority_;
   // |response_info_| is the HTTP response data object which is filled in
   // when a the response headers are read.  It is not owned by this stream.
   HttpResponseInfo* response_info_;
+  bool has_response_status_;  // true if response_status_ as been set.
   // Because response data is buffered, also buffer the response status if the
   // stream is explicitly closed via OnError or OnClose with an error.
   // Once all buffered data has been returned, this will be used as the final
   // response.
   int response_status_;
 
   // Serialized request headers.
   SpdyHeaderBlock request_headers_;
 
   bool response_headers_received_;
@@ skipping 19 matching lines @@
   scoped_refptr<IOBuffer> user_buffer_;
   int user_buffer_len_;
 
   // Temporary buffer used to read the request body from UploadDataStream.
   scoped_refptr<IOBufferWithSize> raw_request_body_buf_;
   // Wraps raw_request_body_buf_ to read the remaining data progressively.
   scoped_refptr<DrainableIOBuffer> request_body_buf_;
 
   NetLogWithSource stream_net_log_;
 
-  QuicErrorCode quic_connection_error_;
+  QuicErrorCode quic_connection_error_;       // Cached connection error code.
+  QuicRstStreamErrorCode quic_stream_error_;  // Cached stream error code.
 
   // True when this stream receives a go away from server due to port migration.
   bool port_migration_detected_;
 
   bool found_promise_;
   // |QuicClientPromisedInfo| owns this. It will be set when |Try()|
   // is asynchronous, i.e. it returned QUIC_PENDING, and remains valid
   // until |OnRendezvouResult()| fires or |push_handle_->Cancel()| is
   // invoked.
   QuicClientPushPromiseIndex::TryHandle* push_handle_;
 
   // Set to true when DoLoop() is being executed, false otherwise.
   bool in_loop_;
 
   // Session connect timing info.
   LoadTimingInfo::ConnectTiming connect_timing_;
 
   base::WeakPtrFactory<QuicHttpStream> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicHttpStream);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CHROMIUM_QUIC_HTTP_STREAM_H_