Network: Fix up previous corruption patch

This is a fix-up for cff39fba10ffc10ee4dcfdc66ff6528eb26462d3.
That patch lead to some internal state issues that lead to the QTBUG-47048
or to QNetworkReply objects erroring with "Connection Closed" when
the server closed the Keep-Alive connection.

This patch changes the QNAM socket slot connections to be DirectConnection.
We don't close the socket anymore in slots where it is anyway in a closed state
afterwards. This prevents event/stack recursions.
We also flush QSslSocket/QTcpSocket receive buffers when receiving a disconnect
so that the developer always gets the full decrypted data from the buffers.

[ChangeLog][QtNetwork] Fix HTTP issues with "Unknown Error" and "Connection Closed"
[ChangeLog][QtNetwork][Sockets] Read OS/encrypted read buffers when connection
closed by server.

Change-Id: Ib4d6a2d0d988317e3a5356f36e8dbcee4590beed
Task-number: QTBUG-47048
Reviewed-by: Kai Koehne <kai.koehne@theqtcompany.com>
Reviewed-by: Richard J. Moore <rich@kde.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/src/network/ssl/qsslsocket.cpp b/src/network/ssl/qsslsocket.cpp
index c1fab94fce..2b9e9230e0 100644
--- a/src/network/ssl/qsslsocket.cpp
+++ b/src/network/ssl/qsslsocket.cpp
@@ -2294,6 +2294,14 @@ void QSslSocketPrivate::_q_errorSlot(QAbstractSocket::SocketError error)
     qCDebug(lcSsl) << "\tstate =" << q->state();
     qCDebug(lcSsl) << "\terrorString =" << q->errorString();
 #endif
+    // this moves encrypted bytes from plain socket into our buffer
+    if (plainSocket->bytesAvailable()) {
+        qint64 tmpReadBufferMaxSize = readBufferMaxSize;
+        readBufferMaxSize = 0; // reset temporarily so the plain sockets completely drained drained
+        transmit();
+        readBufferMaxSize = tmpReadBufferMaxSize;
+    }
+
     q->setSocketError(plainSocket->error());
     q->setErrorString(plainSocket->errorString());
     emit q->error(error);