CommandHistory.cpp

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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

/*
   This is a modified version of a source file from the Rosegarden
   MIDI and audio sequencer and notation editor, copyright 2000-2006
   Chris Cannam, distributed under the GNU General Public License.

   This file contains traces of the KCommandHistory class from the KDE
   project, copyright 2000 Werner Trobin and David Faure and
   distributed under the GNU Lesser General Public License.
*/

#include "CommandHistory.h"

#include "Command.h"

#include <QRegExp>
#include <QMenu>
#include <QToolBar>
#include <QString>
#include <QTimer>

#include <iostream>

CommandHistory *CommandHistory::m_instance = 0;

CommandHistory::CommandHistory() :
    m_undoLimit(50),
    m_redoLimit(50),
    m_menuLimit(15),
    m_savedAt(0),
    m_currentCompound(0),
    m_executeCompound(false),
    m_currentBundle(0),
    m_bundleTimer(0),
    m_bundleTimeout(5000)
{
    m_undoAction = new QAction(QIcon(":/icons/undo.png"), tr("&Undo"), this);
    m_undoAction->setShortcut(tr("Ctrl+Z"));
    m_undoAction->setStatusTip(tr("Undo the last editing operation"));
    connect(m_undoAction, SIGNAL(triggered()), this, SLOT(undo()));
    
    m_undoMenuAction = new QAction(QIcon(":/icons/undo.png"), tr("&Undo"), this);
    connect(m_undoMenuAction, SIGNAL(triggered()), this, SLOT(undo()));
    
    m_undoMenu = new QMenu(tr("&Undo"));
    m_undoMenuAction->setMenu(m_undoMenu);
    connect(m_undoMenu, SIGNAL(triggered(QAction *)),
            this, SLOT(undoActivated(QAction*)));

    m_redoAction = new QAction(QIcon(":/icons/redo.png"), tr("Re&do"), this);
    m_redoAction->setShortcut(tr("Ctrl+Shift+Z"));
    m_redoAction->setStatusTip(tr("Redo the last operation that was undone"));
    connect(m_redoAction, SIGNAL(triggered()), this, SLOT(redo()));
    
    m_redoMenuAction = new QAction(QIcon(":/icons/redo.png"), tr("Re&do"), this);
    connect(m_redoMenuAction, SIGNAL(triggered()), this, SLOT(redo()));

    m_redoMenu = new QMenu(tr("Re&do"));
    m_redoMenuAction->setMenu(m_redoMenu);
    connect(m_redoMenu, SIGNAL(triggered(QAction *)),
            this, SLOT(redoActivated(QAction*)));
}

CommandHistory::~CommandHistory()
{
    m_savedAt = -1;
    clearStack(m_undoStack);
    clearStack(m_redoStack);

    delete m_undoMenu;
    delete m_redoMenu;
}

CommandHistory *
CommandHistory::getInstance()
{
    if (!m_instance) m_instance = new CommandHistory();
    return m_instance;
}

void
CommandHistory::clear()
{
//    std::cerr << "CommandHistory::clear()" << std::endl;
    closeBundle();
    m_savedAt = -1;
    clearStack(m_undoStack);
    clearStack(m_redoStack);
    updateActions();
}

void
CommandHistory::registerMenu(QMenu *menu)
{
    menu->addAction(m_undoAction);
    menu->addAction(m_redoAction);
}

void
CommandHistory::registerToolbar(QToolBar *toolbar)
{
    toolbar->addAction(m_undoMenuAction);
    toolbar->addAction(m_redoMenuAction);
}

void
CommandHistory::addCommand(Command *command)
{
    if (!command) return;

    if (m_currentCompound) {
        addToCompound(command, m_executeCompound);
        return;
    }

    addCommand(command, true);
}

void
CommandHistory::addCommand(Command *command, bool execute, bool bundle)
{
    if (!command) return;

    if (m_currentCompound) {
        addToCompound(command, execute);
        return;
    }

    if (bundle) {
        addToBundle(command, execute);
        return;
    } else if (m_currentBundle) {
        closeBundle();
    }

//    std::cerr << "CommandHistory::addCommand: " << command->getName().toLocal8Bit().data() << " at " << command << std::endl;

    // We can't redo after adding a command
//    std::cerr << "CommandHistory::clearing redo stack" << std::endl;
    clearStack(m_redoStack);

    // can we reach savedAt?
    if ((int)m_undoStack.size() < m_savedAt) m_savedAt = -1; // nope

    m_undoStack.push(command);
    clipCommands();
    
    if (execute) {
        command->execute();
    }

    // Emit even if we aren't executing the command, because
    // someone must have executed it for this to make any sense
    emit commandExecuted();
    emit commandExecuted(command);

    updateActions();
}

void
CommandHistory::addToBundle(Command *command, bool execute)
{
    if (m_currentBundle) {
        if (!command || (command->getName() != m_currentBundleName)) {
            closeBundle();
        }
    }

    if (!command) return;

    if (!m_currentBundle) {
        // need to addCommand before setting m_currentBundle, as addCommand
        // with bundle false will reset m_currentBundle to 0
        MacroCommand *mc = new MacroCommand(command->getName());
        addCommand(mc, false);
        m_currentBundle = mc;
        m_currentBundleName = command->getName();
    }

    if (execute) command->execute();
    m_currentBundle->addCommand(command);

    delete m_bundleTimer;
    m_bundleTimer = new QTimer(this);
    connect(m_bundleTimer, SIGNAL(timeout()), this, SLOT(bundleTimerTimeout()));
    m_bundleTimer->start(m_bundleTimeout);
}

void
CommandHistory::closeBundle()
{
    m_currentBundle = 0;
    m_currentBundleName = "";
}

void
CommandHistory::bundleTimerTimeout()
{
    closeBundle();
}

void
CommandHistory::addToCompound(Command *command, bool execute)
{
//    std::cerr << "CommandHistory::addToCompound: " << command->getName().toLocal8Bit().data() << std::endl;
    if (!m_currentCompound) {
        std::cerr << "CommandHistory::addToCompound: ERROR: no compound operation in progress!" << std::endl;
        return;
    }

    if (execute) command->execute();
    m_currentCompound->addCommand(command);
}

void
CommandHistory::startCompoundOperation(QString name, bool execute)
{
    if (m_currentCompound) {
        std::cerr << "CommandHistory::startCompoundOperation: ERROR: compound operation already in progress!" << std::endl;
        std::cerr << "(name is " << m_currentCompound->getName().toLocal8Bit().data() << ")" << std::endl;
        return;
    }
 
    closeBundle();
   
    m_currentCompound = new MacroCommand(name);
    m_executeCompound = execute;
}

void
CommandHistory::endCompoundOperation()
{
    if (!m_currentCompound) {
        std::cerr << "CommandHistory::endCompoundOperation: ERROR: no compound operation in progress!" << std::endl;
        return;
    }

    MacroCommand *toAdd = m_currentCompound;
    m_currentCompound = 0;

    if (toAdd->haveCommands()) {

        // We don't execute the macro command here, because we have
        // been executing the individual commands as we went along if
        // m_executeCompound was true.
        addCommand(toAdd, false);
    }
}    

void
CommandHistory::addExecutedCommand(Command *command)
{
    addCommand(command, false);
}

void
CommandHistory::addCommandAndExecute(Command *command)
{
    addCommand(command, true);
}

void
CommandHistory::undo()
{
    if (m_undoStack.empty()) return;

    closeBundle();

    Command *command = m_undoStack.top();
    command->unexecute();
    emit commandExecuted();
    emit commandUnexecuted(command);

    m_redoStack.push(command);
    m_undoStack.pop();

    clipCommands();
    updateActions();

    if ((int)m_undoStack.size() == m_savedAt) emit documentRestored();
}

void
CommandHistory::redo()
{
    if (m_redoStack.empty()) return;

    closeBundle();

    Command *command = m_redoStack.top();
    command->execute();
    emit commandExecuted();
    emit commandExecuted(command);

    m_undoStack.push(command);
    m_redoStack.pop();
    // no need to clip

    updateActions();

    if ((int)m_undoStack.size() == m_savedAt) emit documentRestored();
}

void
CommandHistory::setUndoLimit(int limit)
{
    if (limit > 0 && limit != m_undoLimit) {
        m_undoLimit = limit;
        clipCommands();
    }
}

void
CommandHistory::setRedoLimit(int limit)
{
    if (limit > 0 && limit != m_redoLimit) {
        m_redoLimit = limit;
        clipCommands();
    }
}

void
CommandHistory::setMenuLimit(int limit)
{
    m_menuLimit = limit;
    updateActions();
}

void
CommandHistory::setBundleTimeout(int ms)
{
    m_bundleTimeout = ms;
}

void
CommandHistory::documentSaved()
{
    closeBundle();
    m_savedAt = m_undoStack.size();
}

void
CommandHistory::clipCommands()
{
    if ((int)m_undoStack.size() > m_undoLimit) {
        m_savedAt -= (m_undoStack.size() - m_undoLimit);
    }

    clipStack(m_undoStack, m_undoLimit);
    clipStack(m_redoStack, m_redoLimit);
}

void
CommandHistory::clipStack(CommandStack &stack, int limit)
{
    int i;

    if ((int)stack.size() > limit) {

        CommandStack tempStack;

        for (i = 0; i < limit; ++i) {
//          Command *command = stack.top();
//          std::cerr << "CommandHistory::clipStack: Saving recent command: " << command->getName().toLocal8Bit().data() << " at " << command << std::endl;
            tempStack.push(stack.top());
            stack.pop();
        }

        clearStack(stack);

        for (i = 0; i < m_undoLimit; ++i) {
            stack.push(tempStack.top());
            tempStack.pop();
        }
    }
}

void
CommandHistory::clearStack(CommandStack &stack)
{
    while (!stack.empty()) {
        Command *command = stack.top();
        // Not safe to call getName() on a command about to be deleted
//      std::cerr << "CommandHistory::clearStack: About to delete command " << command << std::endl;
        delete command;
        stack.pop();
    }
}

void
CommandHistory::undoActivated(QAction *action)
{
    int pos = m_actionCounts[action];
    for (int i = 0; i <= pos; ++i) {
        undo();
    }
}

void
CommandHistory::redoActivated(QAction *action)
{
    int pos = m_actionCounts[action];
    for (int i = 0; i <= pos; ++i) {
        redo();
    }
}

void
CommandHistory::updateActions()
{
    m_actionCounts.clear();

    for (int undo = 0; undo <= 1; ++undo) {

        QAction *action(undo ? m_undoAction : m_redoAction);
        QAction *menuAction(undo ? m_undoMenuAction : m_redoMenuAction);
        QMenu *menu(undo ? m_undoMenu : m_redoMenu);
        CommandStack &stack(undo ? m_undoStack : m_redoStack);

        if (stack.empty()) {

            QString text(undo ? tr("Nothing to undo") : tr("Nothing to redo"));

            action->setEnabled(false);
            action->setText(text);

            menuAction->setEnabled(false);
            menuAction->setText(text);

        } else {

            action->setEnabled(true);
            menuAction->setEnabled(true);

            QString commandName = stack.top()->getName();
            commandName.replace(QRegExp("&"), "");

            QString text = (undo ? tr("&Undo %1") : tr("Re&do %1"))
                .arg(commandName);

            action->setText(text);
            menuAction->setText(text);
        }

        menu->clear();

        CommandStack tempStack;
        int j = 0;

        while (j < m_menuLimit && !stack.empty()) {

            Command *command = stack.top();
            tempStack.push(command);
            stack.pop();

            QString commandName = command->getName();
            commandName.replace(QRegExp("&"), "");

            QString text;
            if (undo) text = tr("&Undo %1").arg(commandName);
            else      text = tr("Re&do %1").arg(commandName);
            
            QAction *action = menu->addAction(text);
            m_actionCounts[action] = j++;
        }

        while (!tempStack.empty()) {
            stack.push(tempStack.top());
            tempStack.pop();
        }
    }
}

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