Fetch the etag of the folder to see if it has changed before syncing

Notice that this does not work for the toplevel directory yet, as
owncloud does not change the etag of the root folder

src/mirall/folder.cpp

@@ -76,12 +76,10 @@ Folder::Folder(const QString &alias, const QString &path, const QString& secondP
     // check if the local path exists
     checkLocalPath();
 
-    _pollTimer.setSingleShot(true);
     int polltime = cfg.remotePollInterval();
     qDebug() << "setting remote poll timer interval to" << polltime << "msec";
     _pollTimer.setInterval( polltime );
     QObject::connect(&_pollTimer, SIGNAL(timeout()), this, SLOT(slotPollTimerTimeout()));
-    _pollTimer.setSingleShot(true);
     _pollTimer.start();
 
 }
@@ -239,9 +237,21 @@ void Folder::slotPollTimerTimeout()
 {
     qDebug() << "* Polling" << alias() << "for changes. Ignoring all pending events until now";
     _watcher->clearPendingEvents();
-    evaluateSync(QStringList());
+
+    QObject::connect(new RequestEtagJob(secondPath(), this), SIGNAL(etagRetreived(QString)),
+                     this, SLOT(etagRetreived(QString)));
 }
 
+void Folder::etagRetreived(const QString& etag)
+{
+    qDebug() << "* Compare etag " << etag << " with previous etag " << _lastEtag;
+    if (_lastEtag != etag) {
+        _lastEtag = etag;
+        evaluateSync(QStringList());
+    }
+}
+
+
 void Folder::slotChanged(const QStringList &pathList)
 {
     qDebug() << "** Changed was notified on " << pathList;

src/mirall/folder.h

@@ -172,6 +172,7 @@ private slots:
     void slotTransmissionProgress(const Progress::Info& progress);
 
     void slotPollTimerTimeout();
+    void etagRetreived(const QString &);
 
     /**
      * Triggered by a file system watcher on the local sync dir
@@ -212,6 +213,7 @@ protected:
     bool         _wipeDb;
     Progress::Kind _progressKind;
     QTimer        _pollTimer;
+    QString       _lastEtag;
 
     CSYNC *_csync_ctx;
 

src/mirall/owncloudinfo.cpp

@@ -553,4 +553,62 @@ QString ownCloudInfo::webdavUrl(const QString &connection)
     return url;
 }
 
+RequestEtagJob::RequestEtagJob(const QString& dir, QObject* parent)
+    : QObject(parent)
+{
+    QNetworkRequest req;
+    req.setUrl( QUrl( ownCloudInfo::instance()->webdavUrl(ownCloudInfo::instance()->_connection) + dir ) );
+    req.setRawHeader("Depth", "0");
+    QByteArray xml("<?xml version=\"1.0\" ?>\n"
+                   "<d:propfind xmlns:d=\"DAV:\">\n"
+                   "  <d:prop>\n"
+                   "    <d:getetag/>"
+                   "  </d:prop>\n"
+                   "</d:propfind>\n");
+    QBuffer *buf = new QBuffer;
+    buf->setData(xml);
+    buf->open(QIODevice::ReadOnly);
+    _reply = ownCloudInfo::instance()->davRequest("PROPFIND", req, buf);
+    buf->setParent(_reply);
+
+    if( _reply->error() != QNetworkReply::NoError ) {
+        qDebug() << "getting etag: request network error: " << _reply->errorString();
+    }
+
+    connect( _reply, SIGNAL( finished()), SLOT(slotFinished()) );
+    connect( _reply, SIGNAL(error(QNetworkReply::NetworkError)),
+             this, SLOT(slotError()));
+}
+
+void RequestEtagJob::slotFinished()
+{
+    bool ok = false;
+    if (_reply->attribute(QNetworkRequest::HttpStatusCodeAttribute) == 207) {
+        // Parse DAV response
+        QXmlStreamReader reader(_reply);
+        reader.addExtraNamespaceDeclaration(QXmlStreamNamespaceDeclaration("d", "DAV:"));
+        QString etag;
+        while (!reader.atEnd()) {
+            QXmlStreamReader::TokenType type = reader.readNext();
+            if (type == QXmlStreamReader::StartElement &&
+                    reader.namespaceUri() == QLatin1String("DAV:")) {
+                QString name = reader.name().toString();
+                if (name == QLatin1String("getetag")) {
+                    etag = reader.readElementText();
+                }
+            }
+        }
+        emit etagRetreived(etag);
+    }
+    _reply->deleteLater();
+    deleteLater();
+}
+
+void RequestEtagJob::slotError()
+{
+    qDebug() << "RequestEtagJob Error: " << _reply->errorString();
+    _reply->deleteLater();
+    deleteLater();
+}
+
 } // ns Mirall

src/mirall/owncloudinfo.h

@@ -157,6 +157,27 @@ private:
     qint64                         _lastQuotaUsedBytes;
     qint64                         _lastQuotaTotalBytes;
     QString                        _lastEtag;
+
+    friend class RequestEtagJob;
+};
+
+
+
+
+class RequestEtagJob : public QObject {
+    Q_OBJECT
+
+    QNetworkReply *_reply;
+
+public:
+    explicit RequestEtagJob(const QString &dir , QObject* parent = 0);
+
+private slots:
+    void slotFinished();
+    void slotError();
+
+signals:
+    void etagRetreived(const QString &etag);
 };
 
 } // ns Mirall