Add EmacsKeys plugin.

A very simple non-intrusive plugin. Adds a bunch of actions typical emacs user
would expect. Doesn't contain any default key bindings.

Change-Id: Ib30fb46c577e2fdfd4c704e7f4eee7ee27a53c29
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/emacskeys/emacskeysstate.h

@@ -0,0 +1,80 @@
+/**************************************************************************
+**
+** Copyright (c) nsf <no.smile.face@gmail.com>
+** Contact: http://www.qt-project.org/legal
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and Digia.  For licensing terms and
+** conditions see http://qt.digia.com/licensing.  For further information
+** use the contact form at http://qt.digia.com/contact-us.
+**
+** 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.
+**
+** In addition, as a special exception, Digia gives you certain additional
+** rights.  These rights are described in the Digia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+****************************************************************************/
+
+#ifndef EMACSKEYSSTATE_H
+#define EMACSKEYSSTATE_H
+
+#include <QObject>
+
+QT_FORWARD_DECLARE_CLASS(QPlainTextEdit)
+
+namespace EmacsKeys {
+namespace Internal {
+
+enum EmacsKeysAction {
+    KeysAction3rdParty,
+    KeysActionKillWord,
+    KeysActionKillLine,
+    KeysActionOther,
+};
+
+class EmacsKeysState : public QObject
+{
+    Q_OBJECT
+
+public:
+    EmacsKeysState(QPlainTextEdit *edit);
+    ~EmacsKeysState();
+    void setLastAction(EmacsKeysAction action);
+    void beginOwnAction() { m_ignore3rdParty = true; }
+    void endOwnAction(EmacsKeysAction action) {
+        m_ignore3rdParty = false;
+        m_lastAction = action;
+    }
+    EmacsKeysAction lastAction() const { return m_lastAction; }
+
+    int mark() const { return m_mark; }
+    void setMark(int mark) { m_mark = mark; }
+
+private slots:
+    void cursorPositionChanged();
+    void textChanged();
+    void selectionChanged();
+
+private:
+    bool m_ignore3rdParty;
+    int m_mark;
+    EmacsKeysAction m_lastAction;
+    QPlainTextEdit *m_editorWidget;
+};
+
+} // namespace Internal
+} // namespace EmacsKeys
+
+#endif // EMACSKEYSSTATE_H