Make sync journal name generating a method of SyncJournal.

Before it was in Folder, however, the command line client does not
have the Folder class. To not duplicate code, the function to generate
the sync journal name went to SyncEngine class.

src/libsync/syncengine.cpp

@@ -92,7 +92,8 @@ SyncEngine::SyncEngine(AccountPtr account, const QString& localPath,
 
     csync_create(&_csync_ctx, localPath.toUtf8().data(), url_string.toUtf8().data());
 
-    const QString dbFile = _journal->databaseFilePath();
+    const QString dbFile = this->journalDbFilePath();
+    _journal->setDatabaseFilePath( dbFile );
     Q_ASSERT(!dbFile.isEmpty());
     csync_init(_csync_ctx, dbFile.toUtf8().data());
 
@@ -115,6 +116,23 @@ SyncEngine::~SyncEngine()
     csync_destroy(_csync_ctx);
 }
 
+QString SyncEngine::journalDbFilePath() const
+{
+    // localPath always has a trailing slash
+    QString dbFile(_localPath);
+    dbFile.append( QLatin1String(".sync_"));
+    // FIXME: Maybe it is better to only allow different hosts, without path component.
+    QString remoteUrlPath = _remoteUrl.toString();
+    if( _remotePath != QLatin1String("/") ) {
+        remoteUrlPath.append(_remotePath);
+    }
+    QByteArray ba = QCryptographicHash::hash( remoteUrlPath.toUtf8(), QCryptographicHash::Md5);
+    dbFile.append( ba.left(6).toHex() );
+    dbFile.append(".db");
+
+    return dbFile;
+}
+
 //Convert an error code from csync to a user readable string.
 // Keep that function thread safe as it can be called from the sync thread or the main thread
 QString SyncEngine::csyncErrorToString(CSYNC_STATUS err)