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/basetexteditor.cpp

@@ -54,6 +54,7 @@
 #include "convenience.h"
 #include "texteditorsettings.h"
 #include "texteditoroverlay.h"
+#include "circularclipboard.h"
 
 #include <aggregation/aggregate.h>
 #include <coreplugin/actionmanager/actionmanager.h>
@@ -99,6 +100,7 @@
 #include <QtGui/QInputDialog>
 #include <QtGui/QMenu>
 #include <QtGui/QMessageBox>
+#include <QtGui/QClipboard>
 
 //#define DO_FOO
 
@@ -201,6 +203,18 @@ static void convertToPlainText(QString &txt)
     }
 }
 
+static bool isModifierKey(int key)
+{
+    return key == Qt::Key_Shift
+            || key == Qt::Key_Control
+            || key == Qt::Key_Alt
+            || key == Qt::Key_Meta;
+}
+
+static const char kTextBlockMimeType[] = "application/vnd.nokia.qtcreator.blocktext";
+static const char kVerticalTextBlockMimeType[] = "application/vnd.nokia.qtcreator.vblocktext";
+
+
 BaseTextEditorWidget::BaseTextEditorWidget(QWidget *parent)
     : QPlainTextEdit(parent)
 {
@@ -1524,6 +1538,11 @@ void BaseTextEditorWidget::keyPressEvent(QKeyEvent *e)
     d->m_moveLineUndoHack = false;
     d->clearVisibleFoldedBlock();
 
+    if (d->m_isCirculatingClipboard
+            && !isModifierKey(e->key())) {
+        d->m_isCirculatingClipboard = false;
+    }
+
     if (e->key() == Qt::Key_Alt
             && d->m_behaviorSettings.m_keyboardTooltips) {
         d->m_maybeFakeTooltipEvent = true;
@@ -2461,6 +2480,7 @@ BaseTextEditorPrivate::BaseTextEditorPrivate()
     m_requestMarkEnabled(true),
     m_lineSeparatorsAllowed(false),
     m_maybeFakeTooltipEvent(false),
+    m_isCirculatingClipboard(false),
     m_visibleWrapColumn(0),
     m_linkPressed(false),
     m_delayedUpdateTimer(0),
@@ -5742,6 +5762,22 @@ void BaseTextEditorWidget::cut()
     QPlainTextEdit::cut();
 }
 
+void BaseTextEditorWidget::copy()
+{
+    if (!textCursor().hasSelection())
+        return;
+
+    QPlainTextEdit::copy();
+
+    const QMimeData *mimeData = QApplication::clipboard()->mimeData();
+    if (mimeData) {
+        CircularClipboard *circularClipBoard = CircularClipboard::instance();
+        circularClipBoard->collect(duplicateMimeData(mimeData));
+        // We want the latest copied content to be the first one to appear on circular paste.
+        circularClipBoard->toLastCollect();
+    }
+}
+
 void BaseTextEditorWidget::paste()
 {
     if (d->m_inBlockSelectionMode) {
@@ -5750,12 +5786,36 @@ void BaseTextEditorWidget::paste()
     QPlainTextEdit::paste();
 }
 
+void BaseTextEditorWidget::circularPaste()
+{
+    const QMimeData *mimeData = CircularClipboard::instance()->next();
+    if (!mimeData)
+        return;
+
+    QTextCursor cursor = textCursor();
+    if (!d->m_isCirculatingClipboard) {
+        cursor.beginEditBlock();
+        d->m_isCirculatingClipboard = true;
+    } else {
+        cursor.joinPreviousEditBlock();
+    }
+    const int selectionStart = qMin(cursor.position(), cursor.anchor());
+    insertFromMimeData(mimeData);
+    cursor.setPosition(selectionStart, QTextCursor::KeepAnchor);
+    cursor.endEditBlock();
+
+    setTextCursor(flippedCursor(cursor));
+
+    // We want to latest pasted content to replace the system's current clipboard.
+    QPlainTextEdit::copy();
+}
+
 QMimeData *BaseTextEditorWidget::createMimeDataFromSelection() const
 {
     if (d->m_inBlockSelectionMode) {
         QMimeData *mimeData = new QMimeData;
         QString text = d->copyBlockSelection();
-        mimeData->setData(QLatin1String("application/vnd.nokia.qtcreator.vblocktext"), text.toUtf8());
+        mimeData->setData(QLatin1String(kVerticalTextBlockMimeType), text.toUtf8());
         mimeData->setText(text); // for exchangeability
         return mimeData;
     } else if (textCursor().hasSelection()) {
@@ -5829,7 +5889,7 @@ QMimeData *BaseTextEditorWidget::createMimeDataFromSelection() const
             cursor.setPosition(selstart.position());
             cursor.setPosition(selend.position(), QTextCursor::KeepAnchor);
             text = cursor.selectedText();
-            mimeData->setData(QLatin1String("application/vnd.nokia.qtcreator.blocktext"), text.toUtf8());
+            mimeData->setData(QLatin1String(kTextBlockMimeType), text.toUtf8());
         }
         return mimeData;
     }
@@ -5846,8 +5906,8 @@ void BaseTextEditorWidget::insertFromMimeData(const QMimeData *source)
     if (isReadOnly())
         return;
 
-    if (source->hasFormat(QLatin1String("application/vnd.nokia.qtcreator.vblocktext"))) {
-        QString text = QString::fromUtf8(source->data(QLatin1String("application/vnd.nokia.qtcreator.vblocktext")));
+    if (source->hasFormat(QLatin1String(kVerticalTextBlockMimeType))) {
+        QString text = QString::fromUtf8(source->data(QLatin1String(kVerticalTextBlockMimeType)));
         if (text.isEmpty())
             return;
 
@@ -5923,8 +5983,8 @@ void BaseTextEditorWidget::insertFromMimeData(const QMimeData *source)
     bool insertAtBeginningOfLine = ts.cursorIsAtBeginningOfLine(cursor);
 
     if (insertAtBeginningOfLine
-        && source->hasFormat(QLatin1String("application/vnd.nokia.qtcreator.blocktext"))) {
-        text = QString::fromUtf8(source->data(QLatin1String("application/vnd.nokia.qtcreator.blocktext")));
+        && source->hasFormat(QLatin1String(kTextBlockMimeType))) {
+        text = QString::fromUtf8(source->data(QLatin1String(kTextBlockMimeType)));
         if (text.isEmpty())
             return;
     }
@@ -5964,6 +6024,24 @@ void BaseTextEditorWidget::insertFromMimeData(const QMimeData *source)
     setTextCursor(cursor);
 }
 
+QMimeData *BaseTextEditorWidget::duplicateMimeData(const QMimeData *source) const
+{
+    Q_ASSERT(source);
+
+    QMimeData *mimeData = new QMimeData;
+    mimeData->setText(source->text());
+    mimeData->setHtml(source->html());
+    if (source->hasFormat(QLatin1String(kVerticalTextBlockMimeType))) {
+        mimeData->setData(QLatin1String(kVerticalTextBlockMimeType),
+                          source->data(QLatin1String(kVerticalTextBlockMimeType)));
+    } else if (source->hasFormat(QLatin1String(kTextBlockMimeType))) {
+        mimeData->setData(QLatin1String(kTextBlockMimeType),
+                          source->data(QLatin1String(kTextBlockMimeType)));
+    }
+
+    return mimeData;
+}
+
 void BaseTextEditorWidget::appendStandardContextMenuActions(QMenu *menu)
 {
     menu->addSeparator();
@@ -5978,6 +6056,9 @@ void BaseTextEditorWidget::appendStandardContextMenuActions(QMenu *menu)
     a = am->command(Core::Constants::PASTE)->action();
     if (a && a->isEnabled())
         menu->addAction(a);
+    a = am->command(Constants::CIRCULAR_PASTE)->action();
+    if (a && a->isEnabled())
+        menu->addAction(a);
 }
 
 

src/plugins/texteditor/basetexteditor.h

@@ -254,9 +254,12 @@ public:
 public slots:
     void setDisplayName(const QString &title);
 
+    virtual void copy();
     virtual void paste();
     virtual void cut();
 
+    void circularPaste();
+
     void zoomIn(int range = 1);
     void zoomOut(int range = 1);
     void zoomReset();
@@ -334,10 +337,10 @@ protected:
 
     void showEvent(QShowEvent *);
 
-    // reimplemented to support block selection
     QMimeData *createMimeDataFromSelection() const;
     bool canInsertFromMimeData(const QMimeData *source) const;
     void insertFromMimeData(const QMimeData *source);
+    QMimeData *duplicateMimeData(const QMimeData *source) const;
 
     static QString msgTextTooLarge(quint64 size);
 

src/plugins/texteditor/basetexteditor_p.h

@@ -246,6 +246,7 @@ public:
     uint autoParenthesisOverwriteBackup : 1;
     uint surroundWithEnabledOverwriteBackup : 1;
     uint m_maybeFakeTooltipEvent : 1;
+    uint m_isCirculatingClipboard: 1;
     int m_visibleWrapColumn;
 
     QTextCharFormat m_linkFormat;

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;
+}

src/plugins/texteditor/circularclipboard.h

@@ -0,0 +1,63 @@
+/**************************************************************************
+**
+** 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.
+**
+**************************************************************************/
+
+#ifndef CIRCULARCLIPBOARD_H
+#define CIRCULARCLIPBOARD_H
+
+#include <QtCore/QList>
+#include <QtCore/QMimeData>
+
+namespace TextEditor {
+namespace Internal {
+
+class CircularClipboard
+{
+public:
+    static CircularClipboard *instance();
+
+    void collect(const QMimeData *mimeData);
+    const QMimeData *next() const;
+    void toLastCollect();
+
+private:
+    CircularClipboard();
+    ~CircularClipboard();
+    CircularClipboard &operator=(const CircularClipboard &);
+
+    mutable int m_current;
+    QList<const QMimeData *> m_items;
+};
+
+} // namespace Internal
+} // namespace TextEditor
+
+#endif // CIRCULARCLIPBOARD_H

src/plugins/texteditor/texteditor.pro

@@ -110,7 +110,8 @@ SOURCES += texteditorplugin.cpp \
     typingsettings.cpp \
     icodestylepreferences.cpp \
     codestylepool.cpp \
-    codestyleeditor.cpp
+    codestyleeditor.cpp \
+    circularclipboard.cpp
 
 HEADERS += texteditorplugin.h \
     textfilewizard.h \
@@ -225,7 +226,8 @@ HEADERS += texteditorplugin.h \
     icodestylepreferences.h \
     codestylepool.h \
     codestyleeditor.h \
-    basefilefind_p.h
+    basefilefind_p.h \
+    circularclipboard.h
 
 FORMS += \
     displaysettingspage.ui \

src/plugins/texteditor/texteditoractionhandler.cpp

@@ -64,6 +64,7 @@ TextEditorActionHandler::TextEditorActionHandler(const char *context,
     m_copyAction(0),
     m_cutAction(0),
     m_pasteAction(0),
+    m_circularPasteAction(0),
     m_selectAllAction(0),
     m_gotoAction(0),
     m_printAction(0),
@@ -369,6 +370,13 @@ void TextEditorActionHandler::createActions()
     command->setDefaultKeySequence(QKeySequence(tr("Alt+U")));
     connect(m_lowerCaseSelectionAction, SIGNAL(triggered()), this, SLOT(lowercaseSelection()));
 
+    m_circularPasteAction = new QAction(tr("Paste From Circular Clipboard"), this);
+    m_modifyingActions << m_circularPasteAction;
+    command = am->registerAction(m_circularPasteAction, Constants::CIRCULAR_PASTE, m_contextId, true);
+    command->setDefaultKeySequence(QKeySequence(tr("Ctrl+Shift+V")));
+    connect(m_circularPasteAction, SIGNAL(triggered()), this, SLOT(circularPasteAction()));
+    medit->addAction(command, Core::Constants::G_EDIT_COPYPASTE);
+
     QAction *a = 0;
     a = new QAction(tr("Goto Line Start"), this);
     command = am->registerAction(a, Constants::GOTO_LINE_START, m_contextId, true);
@@ -568,6 +576,7 @@ FUNCTION2(redoAction, redo)
 FUNCTION2(copyAction, copy)
 FUNCTION2(cutAction, cut)
 FUNCTION2(pasteAction, paste)
+FUNCTION2(circularPasteAction, circularPaste)
 FUNCTION2(formatAction, format)
 FUNCTION2(rewrapParagraphAction, rewrapParagraph)
 FUNCTION2(selectAllAction, selectAll)

src/plugins/texteditor/texteditoractionhandler.h

@@ -98,6 +98,7 @@ private slots:
     void copyAction();
     void cutAction();
     void pasteAction();
+    void circularPasteAction();
     void selectAllAction();
     void gotoAction();
     void printAction();
@@ -166,6 +167,7 @@ private:
     QAction *m_copyAction;
     QAction *m_cutAction;
     QAction *m_pasteAction;
+    QAction *m_circularPasteAction;
     QAction *m_selectAllAction;
     QAction *m_gotoAction;
     QAction *m_printAction;

src/plugins/texteditor/texteditorconstants.h

@@ -101,6 +101,7 @@ const char INFO_SYNTAX_DEFINITION[] = "TextEditor.InfoSyntaxDefinition";
 const char TASK_DOWNLOAD_DEFINITIONS[] = "TextEditor.Task.Download";
 const char TASK_REGISTER_DEFINITIONS[] = "TextEditor.Task.Register";
 const char TASK_OPEN_FILE[]        = "TextEditor.Task.OpenFile";
+const char CIRCULAR_PASTE[]        = "TextEditor.CircularPaste";
 
 // Text color and style categories
 const char C_TEXT[]                = "Text";