Merge r165745 - [GTK] Don't busy loop when the socket is full

https://bugs.webkit.org/show_bug.cgi?id=129802

Patch by Giovanni Campagna <gcampagna@src.gnome.org> on 2014-03-17
Reviewed by Carlos Garcia Campos.

When the socket is full and we see EAGAIN or EWOULDBLOCK
(because the socket is non blocking), don't busy loop by
tring to write again, instead poll() until the socket
becomes writable.

* Platform/IPC/unix/ConnectionUnix.cpp:
(IPC::Connection::sendOutgoingMessage):

Source/WebKit2/ChangeLog

@@ -1,3 +1,18 @@
+2014-03-17  Giovanni Campagna  <gcampagna@src.gnome.org>
+
+        [GTK] Don't busy loop when the socket is full
+        https://bugs.webkit.org/show_bug.cgi?id=129802
+
+        Reviewed by Carlos Garcia Campos.
+
+        When the socket is full and we see EAGAIN or EWOULDBLOCK
+        (because the socket is non blocking), don't busy loop by
+        tring to write again, instead poll() until the socket
+        becomes writable.
+
+        * Platform/IPC/unix/ConnectionUnix.cpp:
+        (IPC::Connection::sendOutgoingMessage):
+
 2014-03-14  Carlos Garcia Campos  <cgarcia@igalia.com>
 
         [GTK] WebKit2WebExtension GIR can't be used in vala

Source/WebKit2/Platform/IPC/unix/ConnectionUnix.cpp

@@ -34,6 +34,7 @@
 #include <unistd.h>
 #include <errno.h>
 #include <fcntl.h>
+#include <poll.h>
 #include <wtf/Assertions.h>
 #include <wtf/Functional.h>
 #include <wtf/StdLibExtras.h>
@@ -522,8 +523,17 @@ bool Connection::sendOutgoingMessage(std::unique_ptr<MessageEncoder> encoder)
 
     int bytesSent = 0;
     while ((bytesSent = sendmsg(m_socketDescriptor, &message, 0)) == -1) {
-        if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK)
+        if (errno == EINTR)
             continue;
+        if (errno == EAGAIN || errno == EWOULDBLOCK) {
+            struct pollfd pollfd;
+
+            pollfd.fd = m_socketDescriptor;
+            pollfd.events = POLLOUT;
+            pollfd.revents = 0;
+            poll(&pollfd, 1, -1);
+            continue;
+        }
 
         WTFLogAlways("Error sending IPC message: %s", strerror(errno));
         return false;