Restart the sync when we detect we need to redo a sync

Fixes #1968
Relates #2038

(cherry picked from commit a84b7dc27e)

Conflicts:
	src/mirall/owncloudpropagator.h
	src/mirall/propagator_qnam.cpp
	src/mirall/syncengine.h

src/mirall/folder.cpp

@@ -266,6 +266,7 @@ void Folder::slotPollTimerTimeout()
     qDebug() << "* Polling" << alias() << "for changes. (time since last sync:" << (_timeSinceLastSync.elapsed() / 1000) << "s)";
 
     if (quint64(_timeSinceLastSync.elapsed()) > MirallConfigFile().forceSyncInterval() ||
+            _lastEtag.isNull() ||
             !(_syncResult.status() == SyncResult::Success ||_syncResult.status() == SyncResult::Problem)) {
         qDebug() << "** Force Sync now, state is " << _syncResult.statusString();
         emit scheduleToSync(alias());
@@ -659,10 +660,13 @@ void Folder::slotSyncFinished()
 
     bubbleUpSyncResult();
 
-    _engine.reset(0);
+    bool anotherSyncNeeded = false;
+    if (_engine) {
+        anotherSyncNeeded = _engine->isAnotherSyncNeeded();
+        _engine.reset(0);
+    }
     // _watcher->setEventsEnabledDelayed(2000);
-    _pollTimer.start();
-    _timeSinceLastSync.restart();
+
 
 
     if (_csyncError) {
@@ -689,6 +693,16 @@ void Folder::slotSyncFinished()
     // all come in.
     QTimer::singleShot(200, this, SLOT(slotEmitFinishedDelayed() ));
 
+    if (!anotherSyncNeeded) {
+        _pollTimer.start();
+        _timeSinceLastSync.restart();
+    } else {
+        // Another sync is required.  We will make sure that the poll timer occurs soon enough
+        // and we clear the etag to force a sync
+        _lastEtag.clear();
+        QTimer::singleShot(1000, this, SLOT(slotPollTimerTimeout() ));
+    }
+
 }
 
 void Folder::slotEmitFinishedDelayed()

src/mirall/owncloudpropagator.cpp

@@ -144,6 +144,7 @@ bool PropagateItemJob::checkForProblemsWithShared(int httpStatusCode, const QStr
             // Also remove the inodes and fileid from the db so no further renames are tried for
             // this item.
             _propagator->_journal->avoidRenamesOnNextSync(_item._file);
+            _propagator->_anotherSyncNeeded = true;
         }
         if( newJob )  {
             newJob->setRestoreJobMsg(msg);

src/mirall/owncloudpropagator.h

@@ -209,6 +209,7 @@ public:
             , _journal(progressDb)
             , _finishedEmited(false)
             , _activeJobs(0)
+            , _anotherSyncNeeded(false)
     { }
 
     void start(const SyncFileItemVector &_syncedItems);
@@ -221,6 +222,9 @@ public:
     /* The number of currently active jobs */
     int _activeJobs;
 
+    /** We detected that another sync is required after this one */
+    bool _anotherSyncNeeded;
+
     /* The maximum number of active job in parallel  */
     int maximumActiveJob();
 

src/mirall/propagator_qnam.cpp

@@ -422,6 +422,7 @@ void PropagateUploadFileQNAM::slotPutFinished()
         if (Utility::qDateTimeToTime_t(fi.lastModified()) != _item._modtime) {
             qDebug() << "The local file has changed during upload:" << _item._modtime << "!=" << Utility::qDateTimeToTime_t(fi.lastModified())  << fi.lastModified();
             _finished = true;
+            _propagator->_anotherSyncNeeded = true;
             done(SyncFileItem::SoftError, tr("Local file changed during sync."));
             // FIXME:  the legacy code was retrying for a few seconds.
             //         and also checking that after the last chunk, and removed the file in case of INSTRUCTION_NEW

src/mirall/syncengine.cpp

@@ -66,6 +66,7 @@ SyncEngine::SyncEngine(CSYNC *ctx, const QString& localPath, const QString& remo
   , _hasRemoveFile(false)
   , _uploadLimit(0)
   , _downloadLimit(0)
+  , _anotherSyncNeeded(false)
 {
     qRegisterMetaType<SyncFileItem>("SyncFileItem");
     qRegisterMetaType<SyncFileItem::Status>("SyncFileItem::Status");
@@ -727,6 +728,8 @@ void SyncEngine::slotJobCompleted(const SyncFileItem &item)
 
 void SyncEngine::slotFinished()
 {
+    _anotherSyncNeeded = _anotherSyncNeeded || _propagator->_anotherSyncNeeded;
+
     // emit the treewalk results.
     if( ! _journal->postSyncCleanup( _seenFiles ) ) {
         qDebug() << "Cleaning of synced ";
@@ -938,6 +941,7 @@ void SyncEngine::checkForPermission()
                     //  At this point we would need to go back to the propagate phase on both remote to take
                     //  the decision.
                     _journal->avoidRenamesOnNextSync(it->_file);
+                    _anotherSyncNeeded = true;
 
 
                     if (it->_isDirectory) {

src/mirall/syncengine.h

@@ -63,6 +63,9 @@ public:
 
     Utility::StopWatch &stopWatch() { return _stopWatch; }
 
+    /* Return true if we detected that another sync is needed to complete the sync */
+    bool isAnotherSyncNeeded() { return _anotherSyncNeeded; }
+
 signals:
     void csyncError( const QString& );
     void csyncUnavailable();
@@ -145,8 +148,9 @@ private:
 
     // hash containing the permissions on the remote directory
     QHash<QString, QByteArray> _remotePerms;
-};
 
+    bool _anotherSyncNeeded;
+};
 
 class UpdateJob : public QObject {
     Q_OBJECT
@@ -163,7 +167,7 @@ class UpdateJob : public QObject {
     }
 public:
     explicit UpdateJob(CSYNC *ctx, QObject* parent = 0)
-            : QObject(parent), _csync_ctx(ctx) {
+    : QObject(parent), _csync_ctx(ctx) {
         // We need to forward the log property as csync uses thread local
         // and updates run in another thread
         _log_callback = csync_get_log_callback();