Editor: Introduce circular clipboard

This is a clipboard within Creator only. It allows the user to paste/navigate
through the recently copied content by repeatedly triggering a shortcut (which
is by default set to Ctrl+Shift+V).

Task-number: QTCREATORBUG-146
Change-Id: Ie449ab4b304548d5037a0c877bbbc0344d654325
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>

src/plugins/texteditor/circularclipboard.cpp

@@ -0,0 +1,79 @@
+/**************************************************************************
+**
+** 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 info@qt.nokia.com.
+**
+**************************************************************************/
+
+#include "circularclipboard.h"
+
+using namespace TextEditor::Internal;
+
+static const int kMaxSize = 10;
+
+CircularClipboard::CircularClipboard()
+    : m_current(-1)
+{}
+
+CircularClipboard::~CircularClipboard()
+{
+    qDeleteAll(m_items);
+}
+
+CircularClipboard *CircularClipboard::instance()
+{
+    static CircularClipboard clipboard;
+    return &clipboard;
+}
+
+void CircularClipboard::collect(const QMimeData *mimeData)
+{
+    if (m_items.size() > kMaxSize) {
+        delete m_items.last();
+        m_items.removeLast();
+    }
+    m_items.prepend(mimeData);
+}
+
+const QMimeData *CircularClipboard::next() const
+{
+    if (m_items.isEmpty())
+        return 0;
+
+    if (m_current == m_items.length() - 1)
+        m_current = 0;
+    else
+        ++m_current;
+
+    return m_items.at(m_current);
+}
+
+void CircularClipboard::toLastCollect()
+{
+    m_current = -1;
+}