Implement protocol upgrade for HTTP/2 enabled requests

Without ALPN/NPN (== without OpenSSL) we can negotiate HTTP/2
using the protocol upgrade procedure as described by RFC7540.
Since there is no TLS handshake, after our http channel was connected
we first send an 'augmented' HTTP/1.1 request - its header
contains additional 'HTTP2-Settings' and 'Upgrade' (to 'h2c') fields.
If we receive reponse 101 (switch protocol) we re-create a protocol
handler and switch to HTTP/2.

Task-number: QTBUG-50955
Change-Id: I36e9985e06ba76edaf7fdb22bb43770f8d593c61
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/network/access/qhttpprotocolhandler.cpp b/src/network/access/qhttpprotocolhandler.cpp
index b486b75449..ab136af083 100644
--- a/src/network/access/qhttpprotocolhandler.cpp
+++ b/src/network/access/qhttpprotocolhandler.cpp
@@ -129,6 +129,15 @@ void QHttpProtocolHandler::_q_receiveReply()
                 } else {
                     replyPrivate->autoDecompress = false;
                 }
+                if (m_connection->connectionType() == QHttpNetworkConnection::ConnectionTypeHTTP2) {
+                    if (replyPrivate->statusCode == 101) {
+                        QMetaObject::invokeMethod(m_channel, "_q_protocolSwitch", Qt::QueuedConnection);
+                        return;
+                    }
+
+                    // HTTP/2 is not supported? TODO - but can it be something else?
+                    m_channel->requeueSpdyRequests();
+                }
                 if (replyPrivate->statusCode == 100) {
                     replyPrivate->clearHttpLayerInformation();
                     replyPrivate->state = QHttpNetworkReplyPrivate::ReadingStatusState;