plasma-framework/abstractrunner.h

/*
 *   Copyright 2006-2007 Aaron Seigo <aseigo@kde.org>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this program; if not, write to the
 *   Free Software Foundation, Inc.,
 *   51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#ifndef RUNNER_H
#define RUNNER_H

#include <QtCore/QObject>
#include <QtCore/QList>

#include <plasma/plasma_export.h>

class KActionCollection;
class QAction;

namespace Plasma
{

/**
 * A abstract super-class for Plasma Runners
 */
class PLASMA_EXPORT AbstractRunner : public QObject
{
    Q_OBJECT

    public:
        typedef QList<AbstractRunner*> List;

        /**
         * Constrcuts an Runner object. Since AbstractRunner has pure virtuals,
         * this constructor can not be called directly. Rather a subclass must
         * be created
         */
        explicit AbstractRunner( QObject* parent = 0 );
        virtual ~AbstractRunner();

        /**
         * If the runner can run precisely this term, return a QAction, else
         * return 0. The first runner that returns a QAction will be the
         * default runner. Other runner's actions will be suggested in the
         * interface. Non-exact matches should be offered via findMatches.
         * The action will be activated if the user selects it.
         * If the action is informational only and should not be executed,
         * disable the action with setEnabled( false ).
         *
         * If this runner's exact match is selected, the action will not
         * be triggered, but it will be passed into the exec method.
         * @see exec
         *
         * Ownership of the action passes to the AbstractRunner class.
         */
        QAction* exactMatch(const QString& command);

        /**
         * @return the last action generated by exactMatch( const QString& )
         */
        QAction* exactMatch();

        /**
         * Requests the runner to find possible matches for the search term.
         * Includes basic results paging controls via max and offset.
         *
         * @param term the search string to use
         * @param max maximum number of matches to return
         * @param offset the offset into the matched set to start at
         *
         * @return the collection of actions representing the potential matches
         **/
        KActionCollection* matches( const QString& term, int max, int offset );

        /**
         * If the runner has options that the user can interact with to modify
         * what happens when exec or one of the actions created in fillMatches
         * is called, the runner should return true
         */
        virtual bool hasOptions( );

        /**
         * If the hasOptions() returns true, this method will be called to get
         * the widget displaying the options the user can interact with.
         */
        virtual QWidget* options();

        /**
         * Static method is called to load and get a list available of Runners.
         */
        static List loadRunners( QWidget* parent );

    Q_SIGNALS:
        /**
         * When emitted, the interface will update itself to show the new
         * matches. This is meant to be used by asynchronous runners that will
         * only be able to start a query on fillMatches being called with
         * response (and therefore matches) coming later
         */
        void matchesUpdated( KActionCollection* matches );

    protected:
        /**
         * This method is called when there is text input to match. The runner
         * should fill the matches action collection with one action per match
         * to a maximium of max matches starting at offset in the data set
         * If the action is informational only and should not be executed,
         * disable the action with setEnabled( false ).
         *
         * @param matches the action collection to add matches to
         * @param term the current search term
         * @param max the maximum number of results to return
         * @param offset the number of initial results to skip,
         *               used in conjunction with max
         */
        virtual void fillMatches( KActionCollection* matches,
                                  const QString& term,
                                  int max, int offset );

        /**
         * If the runner can run precisely this term, return a QAction, else
         * return 0. The first runner that returns a QAction will be the
         * default runner. Other runner's actions will be suggested in the
         * interface. Non-exact matches should be offered via findMatches.
         * The action will be activated if the user selects it.
         *
         * @param term the current search term
         */
        virtual QAction* accepts(const QString& term) = 0;

        /**
         * Take action on the command. What this means is dependant on the
         * particular runner implementation, e.g. some runners may treat
         * command as a shell command, while others may treat it as an
         * equation or a user name or ...
         *
         * This will be called automatically when the exact match is
         * selected.
         *
         * @param action the QAction provided via exactMatch
         * @param command the full command string
         */
        virtual bool exec(QAction* action, const QString& command) = 0;

    private:
        class Private;
        Private* const d;

    private Q_SLOTS:
        void runExactMatch();
};

} // Plasma namespace

#define K_EXPORT_PLASMA_RUNNER( libname, classname )     \
K_PLUGIN_FACTORY(factory, registerPlugin<classname>();) \
K_EXPORT_PLUGIN(factory("plasma_runner_" #libname))

#endif