diff --git a/gui/fs-watcher.h b/gui/fs-watcher.h
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+++ b/gui/fs-watcher.h
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+/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil -*- */
+/*
+ * Copyright (c) 2012-2013 University of California, Los Angeles
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation;
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ * Author: Jared Lindblom <lindblom@cs.ucla.edu>
+ *         Alexander Afanasyev <alexander.afanasyev@ucla.edu>
+ *         Zhenkai Zhu <zhenkai@cs.ucla.edu>
+ */
+#ifndef FS_WATCHER_H
+#define FS_WATCHER_H
+
+#include <vector>
+#include <QFileSystemWatcher>
+#include <boost/filesystem.hpp>
+
+#include "executor.h"
+
+class FsWatcher : public QObject
+{
+  Q_OBJECT
+
+public:
+  typedef boost::function<void (const boost::filesystem::path &)> LocalFile_Change_Callback;
+
+  // constructor
+  FsWatcher (QString dirPath,
+             LocalFile_Change_Callback onChange, LocalFile_Change_Callback onDelete,
+             QObject* parent = 0);
+
+  // destructor
+  ~FsWatcher ();
+
+private slots:
+  // handle callback from watcher
+  void
+  DidDirectoryChanged (QString dirPath);
+
+  /**
+   * @brief This even will be triggered either by actual file change or via directory change event
+   * (i.e., can happen twice in a row, as well as trigger false alarm)
+   */
+  void
+  DidFileChanged (QString filePath);
+
+private:
+  // handle callback from the watcher
+  void
+  DidDirectoryChanged_Execute (QString dirPath);
+
+  // scan directory and notify callback about any file changes
+  void
+  ScanDirectory_Notify_Execute (QString dirPath);
+
+  // // reconcile directory, find changes
+  // std::vector<sEventInfo>
+  // reconcileDirectory (QHash<QString, qint64> fileList, QString dirPath);
+
+  // // calculate checksum
+  // QByteArray calcChecksum(QString absFilePath);
+
+  // // print Changes (DEBUG)
+  // void printChanges(std::vector<sEventInfo> dirChanges);
+
+private:
+  QFileSystemWatcher* m_watcher; // filesystem watcher
+  Executor m_executor;
+
+  QString m_dirPath; // monitored path
+
+  LocalFile_Change_Callback m_onChange;
+  LocalFile_Change_Callback m_onDelete;
+};
+
+#endif // FILESYSTEMWATCHER_H