WIP: HTTP/2

We need Qt 5.9 for HTTP2 because, even if Qt 5.8 already has support
for it, there is some critical bug in the HTTP2 implementation which
make it unusable [ https://codereview.qt-project.org/186050 and
https://codereview.qt-project.org/186066 ]

When using HTTP2, we can use many more parallel network request, this
is especially good for small file handling

src/libsync/accessmanager.cpp

@@ -77,6 +77,12 @@ QNetworkReply* AccessManager::createRequest(QNetworkAccessManager::Operation op,
  if (verb == "PROPFIND") {
  newRequest.setHeader( QNetworkRequest::ContentTypeHeader, QLatin1String("text/xml; charset=utf-8"));
  }
+
+#if QT_VERSION >= QT_VERSION_CHECK(5, 9, 0)
+ // only enable HTTP2 with Qt 5.9 because Qt 5.8.0 has too many bugs (only use one connection if the server does not support HTTP2)
+ newRequest.setAttribute(QNetworkRequest::HTTP2AllowedAttribute, true);
+#endif
+
  return QNetworkAccessManager::createRequest(op, newRequest, outgoingData);
 }
 

src/libsync/account.h

@@ -167,6 +167,10 @@ class OWNCLOUDSYNC_EXPORT Account : public QObject {
  /** Detects a specific bug in older server versions */
  bool rootEtagChangesNotOnlySubFolderEtags();
 
+ /** True when the server supports HTTP2 */
+ bool isHttp2Supported() { return _http2Supported; }
+ void setHttp2Supported(bool value) { _http2Supported = value; };
+
  void clearCookieJar();
  void lendCookieJarTo(QNetworkAccessManager *guest);
  QString cookieJarPath();
@@ -217,6 +221,7 @@ protected Q_SLOTS:
  QuotaInfo *_quotaInfo;
  QSharedPointer<QNetworkAccessManager> _am;
  QSharedPointer<AbstractCredentials> _credentials;
+ bool _http2Supported = false;
 
  /// Certificates that were explicitly rejected by the user
  QList<QSslCertificate> _rejectedCertificates;

src/libsync/connectionvalidator.cpp

@@ -131,6 +131,15 @@ void ConnectionValidator::slotStatusFound(const QUrl&url, const QVariantMap &inf
  return;
  }
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 9, 0)
+ if (auto job = qobject_cast<AbstractNetworkJob *>(sender())) {
+ if (auto reply = job->reply()) {
+ _account->setHttp2Supported(
+ reply->attribute(QNetworkRequest::HTTP2WasUsedAttribute).toBool());
+ }
+ }
+#endif
+
  // We attempt to work with servers >= 5.0.0 but warn users.
  // Check usages of Account::serverVersionUnsupported() for details.
 

src/libsync/creds/httpcredentials.cpp

@@ -64,7 +64,6 @@ class HttpCredentialsAccessManager : public AccessManager {
  req.setSslConfiguration(sslConfiguration);
  }
 
-
  return AccessManager::createRequest(op, req, outgoingData);
  }
 private:

src/libsync/owncloudpropagator.cpp

@@ -80,18 +80,18 @@ int OwncloudPropagator::maximumActiveTransferJob()
  // disable parallelism when there is a network limit.
  return 1;
  }
- return qCeil(hardMaximumActiveJob()/2.);
+ return qMax(3, qCeil(hardMaximumActiveJob()/2.));
 }
 
 /* The maximum number of active jobs in parallel */
 int OwncloudPropagator::hardMaximumActiveJob()
 {
  static int max = qgetenv("OWNCLOUD_MAX_PARALLEL").toUInt();
- if (!max) {
- max = 6; //default (Qt cannot do more anyway)
-  // TODO: increase this number when using HTTP2
- }
- return max;
+ if (max)
+ return max;
+ if (_account->isHttp2Supported())
+  return 20;
+ return 6; // (Qt cannot do more anyway)
 }
 
 PropagateItemJob::~PropagateItemJob()

src/libsync/owncloudpropagator.h

@@ -279,7 +279,6 @@ class OwncloudPropagator : public QObject {
  SyncJournalDb * const _journal;
  bool _finishedEmited; // used to ensure that finished is only emitted once
 
-
 public:
  OwncloudPropagator(AccountPtr account, const QString &localDir,
  const QString &remoteFolder, SyncJournalDb *progressDb)