Make the CancellableSyncSocket non-blocking on Send, and blocking on Receive

base/sync_socket_posix.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 "base/sync_socket.h"
 
 #include <errno.h>
 #include <limits.h>
+#include <fcntl.h>
 #include <stdio.h>
-#include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/socket.h>
+#include <sys/types.h>
 
 #if defined(OS_SOLARIS)
 #include <sys/filio.h>
 #endif
 
 #include "base/file_util.h"
 #include "base/logging.h"
 
 
 namespace base {
@@ skipping 63 matching lines @@
   }
   int retval = HANDLE_EINTR(close(handle_));
   if (retval < 0)
     DPLOG(ERROR) << "close";
   handle_ = kInvalidHandle;
   return (retval == 0);
 }
 
 size_t SyncSocket::Send(const void* buffer, size_t length) {
   DCHECK_LE(length, kMaxMessageLength);
+  long flags = 0;

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

suggest you only change this for CancelableSyncSocket and not for SyncSocket.

You can implement it so that CancelableSyncSocket calls the base class' Send()
but does the fcntl() before and after.

[no longer working on chromium, 2012/04/13 11:50:50]

Done.

+  flags = fcntl(handle_, F_GETFL, NULL);
+  if (flags >= 0 && !(flags & O_NONBLOCK)) {

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

instead of >= 0, use != -1

[no longer working on chromium, 2012/04/13 11:50:50]

Done.

+    // Set the socket to non-blocking mode if it is blocking.
+    fcntl(handle_, F_SETFL, flags | O_NONBLOCK);
+  }
   const char* charbuffer = static_cast<const char*>(buffer);
   int len = file_util::WriteFileDescriptor(handle_, charbuffer, length);
+  if (-1 == len)

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

good catch on handling -1!

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

please reset the state of the socket after sending and not inside Receive().

[no longer working on chromium, 2012/04/13 11:50:50]

Done.

+    return 0;
+
   return static_cast<size_t>(len);
 }
 
 size_t SyncSocket::Receive(void* buffer, size_t length) {
   DCHECK_LE(length, kMaxMessageLength);
+  long flags = 0;

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

imho this should be done after WriteFileDescriptor in Send and not here.

[no longer working on chromium, 2012/04/13 11:50:50]

Done.

+  flags = fcntl(handle_, F_GETFL, NULL);
+  if (flags >= 0 && (flags & O_NONBLOCK)) {

[tommi (sloooow) - chröme, 2012/04/13 10:28:10]

!= -1

[no longer working on chromium, 2012/04/13 11:50:50]

Done.

+    // Set the socket to blocking mode if it is non-blocking.
+    fcntl(handle_, F_SETFL, flags & ~O_NONBLOCK);
+  }
   char* charbuffer = static_cast<char*>(buffer);
   if (file_util::ReadFromFD(handle_, charbuffer, length))
     return length;
   return 0;
 }
 
 size_t SyncSocket::Peek() {
   int number_chars;
   if (-1 == ioctl(handle_, FIONREAD, &number_chars)) {
     // If there is an error in ioctl, signal that the channel would block.
@@ skipping 11 matching lines @@
   return HANDLE_EINTR(shutdown(handle(), SHUT_RDWR)) >= 0;
 }
 
 // static
 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
                                       CancelableSyncSocket* socket_b) {
   return SyncSocket::CreatePair(socket_a, socket_b);
 }
 
 }  // namespace base