Source: kcompletion.h

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    /* This file is part of the KDE libraries
        Copyright (C) 1999,2000 Carsten Pfeiffer <pfeiffer@kde.org>

        This library 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 of the License, or (at your option) any later version.

        This library 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
        Library General Public License for more details.

        You should have received a copy of the GNU Library General Public License
        along with this library; see the file COPYING.LIB.  If not, write to
        the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
        Boston, MA 02111-1307, USA.
    */

    #ifndef KCOMPLETION_H
    #define KCOMPLETION_H

    #include <qmap.h>
    #include <qlist.h>
    #include <qobject.h>
    #include <qstring.h>
    #include <qstringlist.h>
    #include <qguardedptr.h>

    #include <kglobalsettings.h>

    class KCompTreeNode;
    class KCompletionPrivate;
    class QPopupMenu;

    /**
     * This class offers easy use of "auto-completion", "manual-completion" or
     * "shell completion" on QString objects. A common use is completing filenames
     * or URLs (see @ref KURLCompletion()).
     * But it is not limited to URL-completion -- everything should be completable!
     * The user should be able to complete email-addresses, telephone-numbers,
     * commands, SQL queries, ...
     * Everytime your program knows what the user can type into an edit-field, you
     * should offer completion. With KCompletion, this is very easy, and if you are
     * using a LineEdit-widget (@ref KLineEdit()), it is even more easy.
     * Basically, you tell a KCompletion-object what strings should be completable
     * and whenever completion should be invoked, you call @ref makeCompletion().
     * KLineEdit and (an editable) KComboBox even do this automatically for you.
     *
     * KCompletion offers the completed string via the signal @ref match() and
     * all matching strings (when the result is ambiguous) via the method
     * @ref allMatches().
     *
     * Notice: auto-completion, shell completion and manual completion work
     *         slightly differently:
     *
     * @li auto-completion always returns a complete item as match.
     *     When more than one matching items are available, it will deliver just
     *     the first (depending on sorting order) item. Iterating over all matches is
     *     possible via @ref nextMatch() and @ref previousMatch().
     *
     * @li manual completion works the same way as auto-completion, the
     *     subtle difference is, that it isn't invoked automatically while the user
     *     is typing, but only when the user presses a special key. The difference
     *     of manual and auto-completion is therefore only visible in UI classes,
     *     KCompletion needs to know whether to deliver partial matches
     *     (shell completion) or whole matches (auto/manual completion), therefore
     *     @ref KGlobalSettings::CompletionMan and
     *     @ref KGlobalSettings::CompletionAuto have the exact same effect in
     *     KCompletion.
     *
     * @li shell completion works like how shells complete filenames:
     *     when multiple matches are available, the longest possible string of all
     *     matches is returned (i.e. only a partial item).
     *     Iterating over all matching items (complete, not partial) is possible
     *     via @ref nextMatch() and @ref previousMatch().
     *
     * You don't have to worry much about that though, KCompletion handles
     * that for you, according to the setting @ref setCompletionMode().
     * The default setting is globally configured by the user and read
     * from @ref KGlobalSettings::completionMode().
     *
     * A short example:
     * <pre>
     * KCompletion completion;
     * completion.setOrder( KCompletion::Sorted );
     * completion.addItem( "pfeiffer@kde.org" );
     * completion.addItem( "coolo@kde.org" );
     * completion.addItem( "carpdjih@sp.zrz.tu-berlin.de" );
     * completion.addItem( "carp@cs.tu-berlin.de" );
     *
     * cout << completion.makeCompletion( "ca" ).latin1() << endl;
     * </pre>
     * In shell-completion-mode, this will be "carp"; in auto-completion-
     * mode it will be "carp@cs.tu-berlin.de", as that is alphabetically
     * smaller.
     * If setOrder was set to Insertion, "carpdjih@sp.zrz.tu-berlin.de"
     * would be completed in auto-completion-mode, as that was inserted before
     * "carp@cs.tu-berlin.de".
     *
     * You can dynamically update the completable items by removing and adding them
     * whenever you want.
     * For advanced usage, you could even use multiple KCompletion objects. E.g.
     * imagine an editor like kwrite with multiple open files. You could store
     * items of each file in a different KCompletion object, so that you know (and
     * tell the user) where a completion comes from.
     *
     * Note: KCompletion does not work with strings that contain 0x0 characters
     *       (unicode nul), as this is used internally as a delimiter.
     *
     * You may inherit from KCompletion and override @ref makeCompletion() in
     * special cases (like reading directories/urls and then supplying the
     * contents to KCompletion, as KURLCompletion does), but generally, this is
     * not necessary.
     *
     *
     * @short A generic class for completing QStrings
     * @author Carsten Pfeiffer <pfeiffer@kde.org>
     * @version $Id: kcompletion.h,v 1.39 2000/07/11 22:15:23 putzer Exp $
     */
    class KCompletion : public QObject
    {
        Q_OBJECT

    public:
        /**
         * Constants that represent the order in which KCompletion performs
         * completion-lookups.
         */
        enum CompOrder { Sorted, Insertion, Weighted };

        /**
         * Constructor, nothing special here :)
         */
        KCompletion();

        // FIXME: copy constructor, assignment constructor...

        /**
         * Destructor, nothing special here, either.
         */
        virtual ~KCompletion();

        /**
         * Attempts to find an item in the list of available completions,
         * that begins with @p string. Will either return the first matching item
         * (if there is more than one match) or QString::null, if no match was
         * found.
         *
         * In the latter case, a sound will be issued, depending on
         * @ref isSoundsEnabled().
         * If a match was found, it will also be emitted via the signal
         * @ref match().
         *
         * If this is called twice or more often with the same string while no
         * items were added or removed in the meantime, all available completions
         * will be emitted via the signal @ref matches().
         * This happens only in shell-completion-mode.
         *
         * @returns the matching item, or QString::null if there is no matching
         * item.
         * @see #slotMakeCompletion
         */
        virtual QString makeCompletion( const QString& string );

        /**
         * @returns the next item from the matching-items-list.
         * When reaching the beginning, the list is rotated so it will return the
         * last match and a sound is issued (depending on @ref isSoundsEnabled()).
         * When there is no match, QString::null is returned and
         * a sound is be issued.
         * @see #slotPreviousMatch
         */
        QString previousMatch();

        /**
         * @returns the previous item from the matching-items-list
         * When reaching the last item, the list is rotated, so it will return
         * the first match and a sound is issued (depending on
         * @ref isSoundsEnabled()). When there is no match, QString::null is
         * returned and a sound is issued.
         * @see #slotNextMatch
         */
        QString nextMatch();

        /**
         * @returns the last match. Might be useful if you need to check whether
         * a completion is different from the last one.
         * QString::null is returned when there is no last match.
         */
        virtual const QString& lastMatch() const { return myLastMatch; }

        /**
         * Returns a list of all items inserted into KCompletion. This is useful
         * if you need to save the state of a KCompletion object and restore it
         * later.
         *
         * Important note: when @ref order() == Weighted, then every item in the
         * stringlist has its weight appended, delimited by a colon. E.g. an item
         * "www.kde.org" might look like "www.kde.org:4", where 4 is the weight.
         *
         * This is necessary so that you can save the items along with its
         * weighting on disk and load them back with @ref setItems(), restoring its
         * weight as well. If you really don't want the appended weightings, call
         * @ref setOrder( KCompletion::Insertion )
         * before calling items().
         *
         * @returns a list of all items
         * @see #setItems
         */
        QStringList items() const;

        /**
         * Sets the completion mode to Auto/Manual (see @ref KCompletion
         * documentation), Shell or None.
         * If you don't set the mode explicitly, the global default value
         * KGlobalSettings::completionMode() is used.
         * @ref KGlobalSettings::CompletionNone disables completion.
         * @see #completionMode
         * @see #KGlobalSettings::completionMode
         */
        void setCompletionMode( KGlobalSettings::Completion mode );

        /**
         * @returns the current completion mode.
         * May be different from @ref KGlobalSettings::completionMode(), if you
         * explicitly called @ref setCompletionMode().
         * @see #setCompletionMode
         */
        KGlobalSettings::Completion completionMode() const {
    	return myCompletionMode;
        }

        /**
         * KCompletion offers three different ways in which it offers its items:
         * @li in the order of insertion
         * @li sorted alphabetically
         * @li weighted
         *
         * Choosing weighted makes KCompletion perform an implicit weighting based
         * on how often an item is inserted. Imagine a webbrowser with a location
         * bar, where the user enters URLs. The more often a URL is entered, the
         * higher priority it gets.
         *
         * Note: Setting the order to sorted only affects new inserted items,
         * already existing items will stay in the current order. So you probably
         * want to call setOrder( Sorted ) before inserting items, when you want
         * everything sorted.
         *
         * Default is insertion order
         * @see #order
         */
        void setOrder( CompOrder order ) { myOrder = order; }

        /**
         * @returns the current completion order.
         * @see #setOrder
         */
        CompOrder order() const { return myOrder; }

        /**
         * Setting this to true makes KCompletion behave case insensitively.
         * E.g. makeCompletion( "CA" ); might return "carp@cs.tu-berlin.de".
         * Default is false (case sensitive).
         * @see #ignoreCase
         */
        //  void setIgnoreCase( bool ignoreCase ) { myIgnoreCase = ignoreCase; }

        /**
         * @returns whether KCompletion acts case insensitively or not.
         * Default is false (case sensitive).
         * @see #setIgnoreCase
         */
        //  bool ignoreCase() const { return myIgnoreCase; }

        /**
         * @returns a list of all matching items. Might take some time, when you
         * have LOTS of items.
         */
        QStringList allMatches() { return findAllCompletions( myLastString ); }

        /**
         * Enables playing a sound when
         * @li @ref makeCompletion() can't find a match
         * @li there is a partial completion (= multiple matches in
         *     Shell-completion mode)
         * @li @ref nextMatch() or @ref previousMatch() hit the last possible
         *     match -> rotation
         *
         * For playing the sounds, @ref KNotifyClient() is used.
         *
         * @see #disableSounds
         * @see #isSoundsEnabled
         */
        void enableSounds() { myBeep = true; }

        /**
         * Disables playing sounds.
         * Default is enabled
         * @see #enableSounds
         * @see #isSoundsEnabled
         */
        void disableSounds() { myBeep = false; }

        /**
         * Tells you whether KCompletion will play sounds on certain occasions.
         * Default is enabled
         * @see #enableSounds
         * @see #disableSounds
         */
        bool isSoundsEnabled() const { return myBeep; }

        /**
         * @returns true when more than one match is found
         * @see #multipleMatches
         */
        bool hasMultipleMatches() const { return myHasMultipleMatches; }

    public slots:
        /**
         * Attempts to complete "string" and emits the completion via @ref match().
         * Same as @ref makeCompletion() (just as a slot).
         * @see #makeCompletion
         */
        void slotMakeCompletion( const QString& string ) {
    	(void) makeCompletion( string );
        }

        /**
         * Searches the previous matching item and emits it via @ref match()
         * Same as @ref previousMatch() (just as a slot).
         * @see #previousMatch
         */
        void slotPreviousMatch() {
    	(void) previousMatch();
        }

        /**
         * Searches the next matching item and emits it via @ref match()
         * Same as @ref nextMatch() (just as a slot).
         * @see #nextMatch
         */
        void slotNextMatch() {
    	(void) nextMatch();
        }

        /**
         * Inserts @p items into the list of possible completions.
         * Does the same as @ref setItems(), but does not call @ref clear() before.
         */
        void insertItems( const QStringList& items );

        /**
         * Sets the list of items available for completion. Removes all previous
         * items.
         *
         * Notice: when order() == Weighted, then the weighting is looked up for
         * every item in the stringlist. Every item should have ":number" appended,
         * where number is an unsigned integer, specifying the weighting.
         *
         * If you don't like this, call
         * setOrder( KCompletion::Insertion )
         * before calling setItems().
         *
         * @see #items
         */
        void setItems( const QStringList& );

        /**
         * Adds an item to the list of available completions.
         * Resets the current item-state (@ref previousMatch() and @ref nextMatch()
         * won't work anymore).
         */
        void addItem( const QString& );

        /**
         * Removes an item from the list of available completions.
         * Resets the current item-state (@ref previousMatch() and @ref nextMatch()
         * won't work anymore).
         */
        void removeItem( const QString& );

        /**
         * Removes all inserted items.
         */
        void clear();

    signals:
        /**
         * The matching item. Will be emitted by @ref makeCompletion(),
         * @ref previousMatch() or @ref nextMatch(). May be QString::null if there
         * is no matching item.
         */
        void match( const QString& );

        /**
         * All matching items. Will be emitted by @ref makeCompletion() in shell-
         * completion-mode, when the same string is passed to makeCompletion twice
         * or more often.
         */
        void matches( const QStringList& );

        /**
         * This signal is emitted, when calling @ref makeCompletion() and more than
         * one matching item is found.
         * @see #hasMultipleMatches
         */
        void multipleMatches();

    protected:
        /**
         * This method is called after a completion is found and before the
         * matching string is emitted. You can override this method to modify the
         * string that will be emitted.
         * This is necessary e.g. in @ref KURLCompletion(), where files with spaces
         * in their names are shown escaped ("filename\ with\ spaces"), but stored
         * unescaped inside KCompletion.
         * Never delete that pointer!
         *
         * Default implementation does nothing.
         * @see #postProcessMatches
         */
        virtual void postProcessMatch( QString * /*match*/ ) {}

        /**
         * This method is called before a list of all available completions is
         * emitted via @ref matches. You can override this method to modify the
         * found items before @ref match() or @ref matches() are emitted.
         * Never delete that pointer!
         *
         * Default implementation does nothing.
         * @see #postProcessMatch
         */
        virtual void postProcessMatches( QStringList * /*matches*/ ) {}

    private:
        void 		addItemInternal( const QString&, bool weighted=false );
        QString 		findCompletion( const QString& string );
        const QStringList& 	findAllCompletions( const QString& );
        void 		extractStringsFromNode( const KCompTreeNode *,
    						const QString& beginning,
    						QStringList *matches,
    						bool addWeight = false ) const;

        enum 		BeepMode { NoMatch, PartialMatch, Rotation };
        void 		doBeep( BeepMode );

        QStringList         myMatches;
        KGlobalSettings::Completion myCompletionMode;

        CompOrder 		myOrder;
        QString             myLastString;
        QString 		myLastMatch;
        QString 		myCurrentMatch;
        KCompTreeNode *     myTreeRoot;
        QStringList 	myRotations;
        bool                myBeep;
        bool 		myBackwards;
        bool 		myIgnoreCase;
        bool 		myHasMultipleMatches;
        uint 		myRotationIndex;

        KCompletionPrivate *d;
    };

    /**
     * An abstract base class for adding a completion feature
     * into widgets.
     *
     * This is a convienence class that provides the basic functions
     * needed to add text completion support into widgets.  All that
     * is required is an implementation for the pure virtual function
     * @ref setCompletionText.  Refer to @ref KLineEdit or @ref KComboBox
     * to see how easily such support can be added using this as a base
     * class.
     *
     * @short A basic abstract class for adding text completion support in widgets.
     * @author Dawit Alemayehu <adawit@kde.org>
     */
    class KCompletionBase
    {

    public:

        /**
         * Constants that represent the items whose short-cut
         * key-binding is programmable.  The default key-bindings
         * for these items are defined in @ref KStdAccel().
         */
        enum KeyBindingType {
           TextCompletion,
           PrevCompletionMatch,
           NextCompletionMatch
        };

        // Map for the key binding types mentioned above.
        typedef QMap<KeyBindingType, int> KeyBindingMap;

        /**
        * Default constructor.
        */
        KCompletionBase();

        /**
        * Destructor.
        */
        virtual ~KCompletionBase();

        /**
        * Returns a pointer to the current completion object.
        *
        * If the object does not exist, it is automatically
        * created.  Note that the completion object created
        * here is used by default to handle the signals
        * internally.  It is also deleted when this object's
        * destructor is invoked.  If you do not want these
        * default settings, use @ref setAutoDeleteCompletionObject
        * and @ref setHandleSignals to change the behavior.
        * Alternatively, you can set the boolean parameter to
        * false to disable the automatic handling of the signals
        * by this object.  Note that the boolean argument will be
        * ignored if there already exists a completion object since
        * no new object needs to be created. You need to use either
        * @ref setHandleSignals or @ref setCompletionObject for
        * such cases depending on your requirement.
        *
        * @param hsig if true, handles signals internally.
        * @return a pointer the completion object.
        */
        KCompletion* completionObject( bool hsig = true );

        /**
        * Sets up the completion object to be used.
        *
        * This method assigns the completion object and sets it
        * up to automatically handle the completion and rotation
        * signals internally.  You should use this function if
        * you want to share one completion object among you widgets
        * or need to use a customized completion object.
        *
        * The object assigned through this method is not deleted
        * when this object's destructor is invoked unless you
        * explicitly call @ref setAutoDeleteCompletionObject after
        * calling this method.  Also if you do not want the signals
        * to be handled by an internal implementation, be sure to
        * set the bool argument to false.
        *
        * @param compObj a @ref KCompletion() or a derived child object.
        * @param hsig if true, handles signals internally.
        */
        virtual void setCompletionObject( KCompletion* /*compObj*/, bool hsig = true );

        /**
        * Enables this object to handle completion and rotation
        * events internally.
        *
        * This function simply assigns a boolean value that
        * indicates whether it should handle rotation and
        * completion events or not.  Note that this does not
        * stop the object from emitting signals when these
        * events occur.
        *
        * @param handle if true, handle completion & rotation internally.
        */
        virtual void setHandleSignals( bool /*handle*/ );

        /**
        * Returns true if the completion object is deleted
        * upon this widget's destruction.
        *
        * See @ref setCompletionObject() and @ref enableCompletion()
        * for details.
        *
        * @return true if the completion object
        */
        bool isCompletionObjectAutoDeleted() const { return m_bAutoDelCompObj; }

        /**
        * Sets the completion object when this widget's destructor
        * is called.
        *
        * If the argument is set to true, the completion object
        * is deleted when this widget's destructor is called.
        *
        * @param autoDelete if true, delete completion object on destruction.
        */
        void setAutoDeleteCompletionObject( bool autoDelete ) {
    	m_bAutoDelCompObj = autoDelete;
        }

        /**
        * Sets the widget's ability to emit text completion and
        * rotation signals.
        *
        * Invoking this function with @p enable set to @p false will
        * cause the completion & rotation signals not to be emitted.
        * However, unlike setting the completion object to @p NULL
        * using @ref setCompletionObject, disabling the emition of
        * the signals through this method does not affect the current
        * completion object.
        *
        * There is no need to invoke this function by default.  When a
        * completion object is created through @ref completionObject or
        * @ref setCompletionObject, these signals are set to emit
        * automatically.  Also note that disabling this signals will not
        * necessarily interfere with the objects ability to handle these
        * events internally.  See @ref setHandleSignals.
        *
        * @param enable if false, disables the emittion of completion & rotation signals.
        */
        void setEnableSignals( bool enable ) { m_bEmitSignals = enable; }

        /**
        * Returns true if the object handles the signals
        *
        * @return true if this signals are handled internally.
        */
        bool handleSignals() const { return m_bHandleSignals; }

        /**
        * Returns true if the object emits the signals
        *
        * @return true if signals are emitted
        */
        bool emitSignals() const { return m_bEmitSignals; }

        /**
        * Sets the type of completion to be used.
        *
        * The completion modes supported are those defined in
        * @ref KGlobalSettings().  See below.
        *
        * @param mode Completion type:
        *   @li CompletionNone:  Disables completion feature.
        *   @li CompletionAuto:  Attempts to find a match &
        *                        fills-in the remaining text.
        *   @li CompletionMan:   Acts the same as the above
        *                        except the action has to be
        *                        manually triggered through
        *                        pre-defined completion key.
        *   @li CompletionShell: Mimics the completion feature
        *                        found in typcial *nix shell
        *                        enviornments.
        */
        virtual void setCompletionMode( KGlobalSettings::Completion mode );

        /**
        * Retrieves the current completion mode.
        *
        * The return values are of type @ref KGlobalSettings::Completion.
        * See @ref setCompletionMode() for details.
        *
        * @return the completion mode.
        */
        KGlobalSettings::Completion completionMode() const {
    	return m_iCompletionMode;
        }

        /**
        * Sets the key-binding to be used for manual text
        * completion, text rotation in a history list as
        * well as a completion list.
        *
    	*
        * When the keys set by this function are pressed, a
        * signal defined by the inherting widget will be activated.
        * If the default value or 0 is specified by the second
        * parameter, then the key-binding as defined in the global
        * setting should be used.  This method returns false value
        * for @p key is negative or the supplied key-binding conflicts
        * with the ones set for one of the other features.
        *
        * NOTE: To use a modifier key (Shift, Ctrl, Alt) as part of
        * the key-binding simply simply @p sum up the values of the
        * modifier and the actual key.  For example, to use CTRL+E as
        * a key binding for one of the items, you would simply supply
        * @p "Qt::CtrlButton + Qt::Key_E" as the second argument to this
        * function.
        *
        * @param item the feature whose key-binding needs to be set:
        *
        * @li TextCompletion	the manual completion key-binding.
        * @li PrevCompletionMatch	the previous match key for mutiple completion.
        * @li NextCompletionMatch	the next match key for for multiple completion.
        *
        * @param key key-binding used to rotate down in a list.
        *
        * @return  true if key-binding can successfully be set.
        */
        bool setKeyBinding( KeyBindingType /*item*/ , int key = 0 );

        /**
        * Returns the key-binding used for the specified item.
        *
        * This methods returns the key-binding used to activate
        * the feature feature given by @p item.  If the binding
        * contains modifier key(s), the SUM of the modifier key
        * and the actual key code are returned.
        *
        * @return the key-binding used for the feature given by @p item.
        */
        int getKeyBinding( KeyBindingType item ) const { return m_keyMap[ item ]; }

        /**
        * Sets this object to use global values for key-bindings.
        *
        * This method changes the values of the key bindings for
        * rotation and completion features to the default values
        * provided in KGlobalSettings.
        *
        * NOTE: By default inheriting widgets should uses the
        * global key-bindings so that there will be no need to
        * call this method.
        */
        void useGlobalKeyBindings();

        /*
        * A pure virtual function that must be implemented by
        * all inheriting classes.
        *
        * This function is intended to allow external completion
        * implementions to set completed text appropriately.  It
        * is mostly relevant when the completion mode is set to
        * CompletionAuto and CompletionManual modes. See
        * @ref KCompletionBase::setCompletedText.
        *
        * @param text the completed text to be set in the widget.
        */
        virtual void setCompletedText( const QString& /* text */ ) = 0;

    protected:

         /**
         * Returns an instance of the completion object.
         *
         * This method is only different from @ref completionObject()
         * in that it does not create a new KCompletion object evenif
         * the internal pointer is @p NULL. Use this method to get the
         * pointer to a completion object when inheriting so that you
         * won't inadvertantly create it!!
         *
         * @returns the completion object or NULL if one does not exist.
         */
         KCompletion* compObj() { return m_pCompObj; }

         /**
         * Returns a key-binding maps
         *
         * This method is the same as @ref getKeyBinding() except it
         * returns the whole keymap containing the key-bindings.
         *
         * @return the key-binding used for the feature given by @p item.
         */
         KeyBindingMap getKeyBindings() const { return m_keyMap; }

    private:

        // This method simply sets the autodelete boolen for
        // the completion object, the emit signals and handle
        // signals internally flags to the provided values.
        void setup( bool, bool, bool );

        // Flag that determined whether the completion object
        // should be deleted when this object is destroyed.
        bool m_bAutoDelCompObj;
        // Determines whether this widget handles completion signals
        // internally or not
        bool m_bHandleSignals;
        // Determines whether this widget fires rotation signals
        bool m_bEmitSignals;
        // Stores the completion mode locally.
        KGlobalSettings::Completion m_iCompletionMode;
        // Pointer to Completion object.
        QGuardedPtr<KCompletion> m_pCompObj;
        // Keybindings
        KeyBindingMap m_keyMap;

        // BCI
        KCompletionPrivate *d;
    };

    #endif // KCOMPLETION_H