HTTP/2 - implement the proper 'h2c' (protocol upgrade)

Without TLS (and thus ALPN/NPN negotiation) HTTP/2 requires
a protocol upgrade procedure, as described in RFC 7540, 3.2.
We start as HTTP/1.1 (and thus we create QHttpProtocolHandler first),
augmenting the headers we send with 'Upgrade: h2c'. In case
we receive HTTP/1.1 response with status code 101 ('Switching
Protocols'), we continue as HTTP/2 session, creating QHttp2ProtocolHandler
and pretending the first request we sent was HTTP/2 request
on a real HTTP/2 stream. If the first response is something different
from 101, we continue as HTTP/1.1. This change also required
auto-test update: our toy-server now has to respond to
the initial HTTP/1.1 request on a platform without ALPN/NPN.
As a bonus a subtle flakyness in 'goaway' auto-test went
away (well, it was fixed).

[ChangeLog][QtNetwork][HTTP/2] In case of clear text HTTP/2 we
now initiate a required protocol upgrade procedure instead of
'H2Direct' connection.

Task-number: QTBUG-61397
Change-Id: I573fa304fdaf661490159037dc47775d97c8ea5b
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
Reviewed-by: Timur Pocheptsov <timur.pocheptsov@qt.io>

1 files changed, 30 insertions, 5 deletions

diff --git a/src/network/access/qhttpnetworkconnection.cpp b/src/network/access/qhttpnetworkconnection.cpp
index ae30d3a8cf..0b474ba116 100644
--- a/src/network/access/qhttpnetworkconnection.cpp
+++ b/src/network/access/qhttpnetworkconnection.cpp
@@ -627,7 +627,8 @@ QHttpNetworkReply* QHttpNetworkConnectionPrivate::queueRequest(const QHttpNetwor
     if (request.isPreConnect())
         preConnectRequests++;
 
-    if (connectionType == QHttpNetworkConnection::ConnectionTypeHTTP) {
+    if (connectionType == QHttpNetworkConnection::ConnectionTypeHTTP
+        || (!encrypt && connectionType == QHttpNetworkConnection::ConnectionTypeHTTP2 && !channels[0].switchedToHttp2)) {
         switch (request.priority()) {
         case QHttpNetworkRequest::HighPriority:
             highPriorityQueue.prepend(pair);
@@ -638,7 +639,7 @@ QHttpNetworkReply* QHttpNetworkConnectionPrivate::queueRequest(const QHttpNetwor
             break;
         }
     }
-    else { // SPDY, HTTP/2
+    else { // SPDY, HTTP/2 ('h2' mode)
         if (!pair.second->d_func()->requestIsPrepared)
             prepareRequest(pair);
         channels[0].spdyRequestsToSend.insertMulti(request.priority(), pair);
@@ -672,6 +673,25 @@ QHttpNetworkReply* QHttpNetworkConnectionPrivate::queueRequest(const QHttpNetwor
     return reply;
 }
 
+void QHttpNetworkConnectionPrivate::fillHttp2Queue()
+{
+    for (auto &pair : highPriorityQueue) {
+        if (!pair.second->d_func()->requestIsPrepared)
+            prepareRequest(pair);
+        channels[0].spdyRequestsToSend.insertMulti(QHttpNetworkRequest::HighPriority, pair);
+    }
+
+    highPriorityQueue.clear();
+
+    for (auto &pair : lowPriorityQueue) {
+        if (!pair.second->d_func()->requestIsPrepared)
+            prepareRequest(pair);
+        channels[0].spdyRequestsToSend.insertMulti(pair.first.priority(), pair);
+    }
+
+    lowPriorityQueue.clear();
+}
+
 void QHttpNetworkConnectionPrivate::requeueRequest(const HttpMessagePair &pair)
 {
     Q_Q(QHttpNetworkConnection);
@@ -1047,8 +1067,7 @@ void QHttpNetworkConnectionPrivate::_q_startNextRequest()
     }
     case QHttpNetworkConnection::ConnectionTypeHTTP2:
     case QHttpNetworkConnection::ConnectionTypeSPDY: {
-
-        if (channels[0].spdyRequestsToSend.isEmpty())
+        if (channels[0].spdyRequestsToSend.isEmpty() && channels[0].switchedToHttp2)
             return;
 
         if (networkLayerState == IPv4)
@@ -1057,7 +1076,7 @@ void QHttpNetworkConnectionPrivate::_q_startNextRequest()
             channels[0].networkLayerPreference = QAbstractSocket::IPv6Protocol;
         channels[0].ensureConnection();
         if (channels[0].socket && channels[0].socket->state() == QAbstractSocket::ConnectedState
-                && !channels[0].pendingEncrypt)
+                && !channels[0].pendingEncrypt && channels[0].spdyRequestsToSend.size())
             channels[0].sendRequest();
         break;
     }
@@ -1355,6 +1374,12 @@ QHttpNetworkReply* QHttpNetworkConnection::sendRequest(const QHttpNetworkRequest
     return d->queueRequest(request);
 }
 
+void QHttpNetworkConnection::fillHttp2Queue()
+{
+    Q_D(QHttpNetworkConnection);
+    d->fillHttp2Queue();
+}
+
 bool QHttpNetworkConnection::isSsl() const
 {
     Q_D(const QHttpNetworkConnection);