QAbstractSocket: wait with closing until all bytes have been written

only disconnect from host when all bytes have been written; i.e. not
only check whether the write buffer is empty, but also check whether
the socket engine has still bytes to write. This is necessary for
HTTP and SOCKS5 socket engine, because they both contain an inner TCP
socket which also does buffering. For the native socket engine, there
is no difference with this patch.

Reviewed-by: Markus Goetz
Reviewed-by: Thiago Macieira

1 files changed, 15 insertions, 7 deletions

diff --git a/src/network/socket/qabstractsocket.cpp b/src/network/socket/qabstractsocket.cpp
index 9fb0b47..955fee0 100644
--- a/src/network/socket/qabstractsocket.cpp
+++ b/src/network/socket/qabstractsocket.cpp
@@ -669,11 +669,11 @@ bool QAbstractSocketPrivate::canWriteNotification()
 
     if (socketEngine) {
 #if defined (Q_OS_WIN)
-	if (!writeBuffer.isEmpty())
-	    socketEngine->setWriteNotificationEnabled(true);
+        if (!writeBuffer.isEmpty())
+            socketEngine->setWriteNotificationEnabled(true);
 #else
-	if (writeBuffer.isEmpty())
-	    socketEngine->setWriteNotificationEnabled(false);
+        if (writeBuffer.isEmpty() && socketEngine->bytesToWrite() == 0)
+            socketEngine->setWriteNotificationEnabled(false);
 #endif
     }
 
@@ -710,11 +710,17 @@ void QAbstractSocketPrivate::connectionNotification()
 bool QAbstractSocketPrivate::flush()
 {
     Q_Q(QAbstractSocket);
-    if (!socketEngine || !socketEngine->isValid() || writeBuffer.isEmpty()) {
+    if (!socketEngine || !socketEngine->isValid() || (writeBuffer.isEmpty()
+        && socketEngine->bytesToWrite() == 0)) {
 #if defined (QABSTRACTSOCKET_DEBUG)
     qDebug("QAbstractSocketPrivate::flush() nothing to do: valid ? %s, writeBuffer.isEmpty() ? %s",
            socketEngine->isValid() ? "yes" : "no", writeBuffer.isEmpty() ? "yes" : "no");
 #endif
+
+        // this covers the case when the buffer was empty, but we had to wait for the socket engine to finish
+        if (state == QAbstractSocket::ClosingState)
+            q->disconnectFromHost();
+
         return false;
     }
 
@@ -751,7 +757,8 @@ bool QAbstractSocketPrivate::flush()
         }
     }
 
-    if (writeBuffer.isEmpty() && socketEngine && socketEngine->isWriteNotificationEnabled())
+    if (writeBuffer.isEmpty() && socketEngine && socketEngine->isWriteNotificationEnabled()
+        && !socketEngine->bytesToWrite())
         socketEngine->setWriteNotificationEnabled(false);
     if (state == QAbstractSocket::ClosingState)
         q->disconnectFromHost();
@@ -2347,7 +2354,8 @@ void QAbstractSocket::disconnectFromHostImplementation()
         }
 
         // Wait for pending data to be written.
-        if (d->socketEngine && d->socketEngine->isValid() && d->writeBuffer.size() > 0) {
+        if (d->socketEngine && d->socketEngine->isValid() && (d->writeBuffer.size() > 0
+            || d->socketEngine->bytesToWrite() > 0)) {
             d->socketEngine->setWriteNotificationEnabled(true);
 
 #if defined(QABSTRACTSOCKET_DEBUG)