Utils: Introduce FileSystemWatcher.

Remove duplicated classes ProjectExplorer::FileWatcher
and QmlProjectManager::FileSystemWatcher, create
Utils::FileSystemWatcher from them, merging the functionality.

Also use in HelpManager/Maemo, reducing the number
of QFileSystemWatcher instances (and thus, shutdown time).

src/libs/utils/filesystemwatcher.h

@@ -0,0 +1,94 @@
+/**************************************************************************
+**
+** This file is part of Qt Creator
+**
+** Copyright (c) 2011 Nokia Corporation and/or its subsidiary(-ies).
+**
+** Contact: Nokia Corporation (info@qt.nokia.com)
+**
+**
+** GNU Lesser General Public License Usage
+**
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this file.
+** Please review the following information to ensure the GNU Lesser General
+** Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights. These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** Other Usage
+**
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**************************************************************************/
+
+#ifndef FSWATCHER_H
+#define FSWATCHER_H
+
+#include "utils_global.h"
+
+#include <QtCore/QObject>
+#include <QtCore/QStringList>
+
+namespace Utils {
+class FileSystemWatcherPrivate;
+
+// Documentation inside.
+class QTCREATOR_UTILS_EXPORT FileSystemWatcher : public QObject
+{
+    Q_DISABLE_COPY(FileSystemWatcher)
+    Q_OBJECT
+public:
+    enum WatchMode
+    {
+        WatchModifiedDate,
+        WatchAllChanges
+    };
+
+    explicit FileSystemWatcher(QObject *parent = 0);
+    explicit FileSystemWatcher(int id, QObject *parent = 0);
+    virtual ~FileSystemWatcher();
+
+    void addFile(const QString &file, WatchMode wm);
+    void addFiles(const QStringList &files, WatchMode wm);
+
+    void removeFile(const QString &file);
+    void removeFiles(const QStringList &files);
+
+    bool watchesFile(const QString &file) const;
+    QStringList files() const;
+
+    void addDirectory(const QString &file, WatchMode wm);
+    void addDirectories(const QStringList &files, WatchMode wm);
+
+    void removeDirectory(const QString &file);
+    void removeDirectories(const QStringList &files);
+
+    bool watchesDirectory(const QString &file) const;
+    QStringList directories() const;
+
+private slots:
+    void slotFileChanged(const QString &path);
+    void slotDirectoryChanged(const QString &path);
+
+signals:
+    void fileChanged(const QString &path);
+    void directoryChanged(const QString &path);
+
+private:
+    void init();
+
+    QScopedPointer<FileSystemWatcherPrivate> d;
+};
+
+} // namespace Utils
+
+#endif // FSWATCHER_H