Reland 10000004 - 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 65 matching lines @@
   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);
   const char* charbuffer = static_cast<const char*>(buffer);
   int len = file_util::WriteFileDescriptor(handle_, charbuffer, length);
-  return static_cast<size_t>(len);
+
+  return (len == -1) ? 0 : static_cast<size_t>(len);
 }
 
 size_t SyncSocket::Receive(void* buffer, size_t length) {
   DCHECK_LE(length, kMaxMessageLength);
   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.
     return 0;
   }
   return (size_t) number_chars;
 }
 
 CancelableSyncSocket::CancelableSyncSocket() {}
 CancelableSyncSocket::CancelableSyncSocket(Handle handle)
     : SyncSocket(handle) {
 }
 
 bool CancelableSyncSocket::Shutdown() {
   return HANDLE_EINTR(shutdown(handle(), SHUT_RDWR)) >= 0;
 }
 
+size_t CancelableSyncSocket::Send(const void* buffer, size_t length) {
+  long flags = 0;
+  flags = fcntl(handle_, F_GETFL, NULL);
+  if (flags != -1 && (flags & O_NONBLOCK) == 0) {
+    // Set the socket to non-blocking mode for sending if its original mode
+    // is blocking.
+    fcntl(handle_, F_SETFL, flags | O_NONBLOCK);
+  }
+
+  size_t len = SyncSocket::Send(buffer, length);
+
+  if (flags != -1 && (flags & O_NONBLOCK) == 0) {
+    // Restore the original flags.
+    fcntl(handle_, F_SETFL, flags);
+  }
+
+  return len;
+}
+
 // static
 bool CancelableSyncSocket::CreatePair(CancelableSyncSocket* socket_a,
                                       CancelableSyncSocket* socket_b) {
   return SyncSocket::CreatePair(socket_a, socket_b);
 }
 
 }  // namespace base