Add taskhandler interface

 * A taskhandler is a class used to implement actions that can
   be done on tasks. This allows for decoupling the taskwindow from
   the functionality it provides, allowing for extensions to provide
   new actions there.

Reviewed-by: dt

src/plugins/projectexplorer/itaskhandler.h

+/**************************************************************************
+**
+** This file is part of Qt Creator
+**
+** Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+**
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** Commercial Usage
+**
+** Licensees holding valid Qt Commercial licenses may use this file in
+** accordance with the Qt Commercial License Agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Nokia.
+**
+** GNU Lesser General Public License Usage
+**
+** Alternatively, 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.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at http://qt.nokia.com/contact.
+**
+**************************************************************************/
+
+#ifndef PROJECTEXPLORER_ITASKHANDLER_H
+#define PROJECTEXPLORER_ITASKHANDLER_H
+
+#include "projectexplorer_export.h"
+
+#include <QtCore/QObject>
+#include <QtCore/QString>
+
+QT_BEGIN_NAMESPACE
+class QAction;
+class QObject;
+QT_END_NAMESPACE
+
+namespace ProjectExplorer {
+class Task;
+
+class PROJECTEXPLORER_EXPORT ITaskHandler : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit ITaskHandler(const QString &id) :
+        m_id(id)
+    { }
+
+    QString id() const
+    {
+        return m_id;
+    }
+
+    virtual bool canHandle(const Task &) { return true; }
+    virtual void handle(const Task &) = 0;
+    virtual QAction *createAction(QObject *parent = 0) = 0;
+
+private:
+    const QString m_id;
+};
+
+} // namespace ProjectExplorer
+
+#endif // PROJECTEXPLORER_ITASKHANDLER_H

src/plugins/projectexplorer/projectexplorer.pro

@@ -17,6 +17,7 @@ HEADERS += projectexplorer.h \
     target.h \
     targetsettingspanel.h \
     task.h \
+    itaskhandler.h \
     taskwindow.h \
     outputwindow.h \
     persistentsettings.h \