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

base/sync_socket_posix.cc

Index: base/sync_socket_posix.cc
diff --git a/base/sync_socket_posix.cc b/base/sync_socket_posix.cc
index c5dca752b2de81da10f475cf30a3e74bc020513c..3657e32e2678e693bee964babc64cb4d922f8ea4 100644
--- a/base/sync_socket_posix.cc
+++ b/base/sync_socket_posix.cc
@@ -6,10 +6,11 @@
 
 #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>
@@ -93,13 +94,28 @@ bool SyncSocket::Close() {
 
 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;