make SetReceiveBufferSize and SetSendBufferSize return net error codes (instead of bools)

net/udp/udp_socket_libevent.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/udp/udp_socket_libevent.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <netdb.h>
 #include <net/if.h>
@@ skipping 297 matching lines @@
   }
   rv = DoBind(address);
   if (rv < 0) {
     Close();
     return rv;
   }
   local_address_.reset();
   return rv;
 }
 
-bool UDPSocketLibevent::SetReceiveBufferSize(int32 size) {
+int UDPSocketLibevent::SetReceiveBufferSize(int32 size) {
   DCHECK(CalledOnValidThread());
   int rv = setsockopt(socket_, SOL_SOCKET, SO_RCVBUF,
                       reinterpret_cast<const char*>(&size), sizeof(size));
-  DCHECK(!rv) << "Could not set socket receive buffer size: " << errno;
-  return rv == 0;
+  int last_error = errno;
+  DCHECK(!rv) << "Could not set socket receive buffer size: " << last_error;
+  return MapSystemError(last_error);

[wtc, 2014/03/29 13:30:12]

This should be:
    return rv == 0 ? OK : MapSystemError(last_error);

The reason is that the value of errno is only trustworthy when a function fails.
A function is not required to set errno to 0 when it succeeds, so errno may
contain a stale error from a previous failed function call.

[jar (doing other things), 2014/04/01 23:50:39]

Done.

 }
 
-bool UDPSocketLibevent::SetSendBufferSize(int32 size) {
+int UDPSocketLibevent::SetSendBufferSize(int32 size) {
   DCHECK(CalledOnValidThread());
   int rv = setsockopt(socket_, SOL_SOCKET, SO_SNDBUF,
                       reinterpret_cast<const char*>(&size), sizeof(size));
-  DCHECK(!rv) << "Could not set socket send buffer size: " << errno;
-  return rv == 0;
+  int last_error = errno;
+  DCHECK(!rv) << "Could not set socket send buffer size: " << last_error;
+  return MapSystemError(last_error);

[wtc, 2014/03/29 13:30:12]

This should be: return rv == 0 ? OK : MapSystemError(last_error);

[jar (doing other things), 2014/04/01 23:50:39]

Done.

 }
 
 void UDPSocketLibevent::AllowAddressReuse() {
   DCHECK(CalledOnValidThread());
   DCHECK(!is_connected());
 
   socket_options_ |= SOCKET_OPTION_REUSE_ADDRESS;
 }
 
 void UDPSocketLibevent::AllowBroadcast() {
@@ skipping 423 matching lines @@
     return MapSystemError(errno);
 
   return OK;
 }
 
 void UDPSocketLibevent::DetachFromThread() {
   base::NonThreadSafe::DetachFromThread();
 }
 
 }  // namespace net