gecko/widget/gtk2/nsGtkKeyUtils.h

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* vim:expandtab:shiftwidth=4:tabstop=4:
 */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is Christopher Blizzard
 * <blizzard@mozilla.org>.  Portions created by the Initial Developer
 * are Copyright (C) 2001 the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef __nsGdkKeyUtils_h__
#define __nsGdkKeyUtils_h__

#include "nsEvent.h"
#include "nsTArray.h"

#include <gdk/gdk.h>

namespace mozilla {
namespace widget {

/**
 *  KeymapWrapper is a wrapper class of GdkKeymap.  GdkKeymap doesn't support
 *  all our needs, therefore, we need to access lower level APIs.
 *  But such code is usually complex and might be slow.  Against such issues,
 *  we should cache some information.
 *
 *  This class provides only static methods.  The methods is using internal
 *  singleton instance which is initialized by default GdkKeymap.  When the
 *  GdkKeymap is destroyed, the singleton instance will be destroyed.
 */

class KeymapWrapper
{
public:
    /**
     * Compute an our DOM keycode from a GDK keyval.
     */
    static PRUint32 ComputeDOMKeyCode(guint aGDKKeyval);

    /**
     * Returns a GDK keyval which is related to the aDOMKeyCode.  However,
     * it may not be same as original value since there are some lost
     * information.
     */
    static guint GuessGDKKeyval(PRUint32 aDOMKeyCode);

    /**
     * Modifier is list of modifiers which we support in widget level.
     */
    enum Modifier {
        NOT_MODIFIER       = 0x0000,
        CAPS_LOCK          = 0x0001,
        NUM_LOCK           = 0x0002,
        SCROLL_LOCK        = 0x0004,
        SHIFT              = 0x0008,
        CTRL               = 0x0010,
        ALT                = 0x0020,
        SUPER              = 0x0040,
        HYPER              = 0x0080,
        META               = 0x0100,
        ALTGR              = 0x0200
    };

    /**
     * Modifiers is used for combination of Modifier.
     * E.g., |Modifiers modifiers = (SHIFT | CTRL);| means Shift and Ctrl.
     */
    typedef PRUint32 Modifiers;

    /**
     * GetCurrentModifierState() returns current modifier key state.
     * The "current" means actual state of hardware keyboard when this is
     * called.  I.e., if some key events are not still dispatched by GDK,
     * the state may mismatch with GdkEventKey::state.
     *
     * @return                  Current modifier key state.
     */
    static guint GetCurrentModifierState();

    /**
     * AreModifiersCurrentlyActive() checks the "current" modifier state
     * on aGdkWindow with the keymap of the singleton instance.
     *
     * @param aModifiers        One or more of Modifier values except
     *                          NOT_MODIFIER.
     * @return                  TRUE if all of modifieres in aModifiers are
     *                          active.  Otherwise, FALSE.
     */
    static bool AreModifiersCurrentlyActive(Modifiers aModifiers);

    /**
     * InitInputEvent() initializes the aInputEvent with aModifierState.
     */
    static void InitInputEvent(nsInputEvent& aInputEvent,
                               guint aModifierState);

    /**
     * InitKeyEvent() intializes aKeyEvent's modifier key related members
     * and keycode related values.
     *
     * @param aKeyEvent         It's an nsKeyEvent which needs to be
     *                          initialized.
     * @param aGdkKeyEvent      A native GDK key event.
     */
    static void InitKeyEvent(nsKeyEvent& aKeyEvent, GdkEventKey* aGdkKeyEvent);

    /**
     * IsKeyPressEventNecessary() returns TRUE when aGdkKeyEvent should cause
     * a DOM keypress event.  Otherwise, FALSE.
     */
    static bool IsKeyPressEventNecessary(GdkEventKey* aGdkKeyEvent);

protected:

    /**
     * GetInstance() returns a KeymapWrapper instance.
     *
     * @return                  A singleton instance of KeymapWrapper.
     */
    static KeymapWrapper* GetInstance();

    KeymapWrapper();
    ~KeymapWrapper();

    bool mInitialized;

    /**
     * Initializing methods.
     */
    void Init();
    void InitBySystemSettings();

    /**
     * mModifierKeys stores each hardware key information.
     */
    struct ModifierKey {
        guint mHardwareKeycode;
        guint mMask;

        ModifierKey(guint aHardwareKeycode) :
          mHardwareKeycode(aHardwareKeycode), mMask(0)
        {
        }
    };
    nsTArray<ModifierKey> mModifierKeys;

    /**
     * GetModifierKey() returns modifier key information of the hardware
     * keycode.  If the key isn't a modifier key, returns NULL.
     */
    ModifierKey* GetModifierKey(guint aHardwareKeycode);

    /**
     * mModifierMasks is bit masks for each modifier.  The index should be one
     * of ModifierIndex values.
     */
    enum ModifierIndex {
        INDEX_NUM_LOCK,
        INDEX_SCROLL_LOCK,
        INDEX_ALT,
        INDEX_SUPER,
        INDEX_HYPER,
        INDEX_META,
        INDEX_ALTGR,
        COUNT_OF_MODIFIER_INDEX
    };
    guint mModifierMasks[COUNT_OF_MODIFIER_INDEX];

    guint GetModifierMask(Modifier aModifier) const;

    /**
     * @param aGdkKeyval        A GDK defined modifier key value such as
     *                          GDK_Shift_L.
     * @return                  Returns Modifier values for aGdkKeyval.
     *                          If the given key code isn't a modifier key,
     *                          returns NOT_MODIFIER.
     */
    static Modifier GetModifierForGDKKeyval(guint aGdkKeyval);

#ifdef PR_LOGGING
    static const char* GetModifierName(Modifier aModifier);
#endif // PR_LOGGING

    /**
     * AreModifiersActive() just checks whether aModifierState indicates
     * all modifiers in aModifiers are active or not.
     *
     * @param aModifiers        One or more of Modifier values except
     *                          NOT_MODIFIER.
     * @param aModifierState    GDK's modifier states.
     * @return                  TRUE if aGdkModifierType indecates all of
     *                          modifieres in aModifier are active.
     *                          Otherwise, FALSE.
     */
    bool AreModifiersActive(Modifiers aModifiers,
                            guint aModifierState) const;

    /**
     * mGdkKeymap is a wrapped instance by this class.
     */
    GdkKeymap* mGdkKeymap;

    /**
     * Pointer of the singleton instance.
     */
    static KeymapWrapper* sInstance;

    /**
     * Signal handlers.
     */
    static void OnKeysChanged(GdkKeymap* aKeymap, KeymapWrapper* aKeymapWrapper);
    static void OnDestroyKeymap(KeymapWrapper* aKeymapWrapper,
                                GdkKeymap *aGdkKeymap);

    /**
     * GetCharCodeFor() Computes what character is inputted by the key event
     * with aModifierState and aGroup.
     *
     * @param aGdkKeyEvent      Native key event, must not be NULL.
     * @param aModifierState    Combination of GdkModifierType which you
     *                          want to test with aGdkKeyEvent.
     * @param aGroup            Set group in the mGdkKeymap.
     * @return                  charCode which is inputted by aGdkKeyEvent.
     *                          If failed, this returns 0.
     */
    static PRUint32 GetCharCodeFor(const GdkEventKey *aGdkKeyEvent);
    PRUint32 GetCharCodeFor(const GdkEventKey *aGdkKeyEvent,
                            guint aModifierState,
                            gint aGroup);

    /**
     * GetKeyLevel() returns level of the aGdkKeyEvent in mGdkKeymap.
     *
     * @param aGdkKeyEvent      Native key event, must not be NULL.
     * @return                  Using level.  Typically, this is 0 or 1.
     *                          If failed, this returns -1.
     */
    gint GetKeyLevel(GdkEventKey *aGdkKeyEvent);

    /**
     * IsBasicLatinLetterOrNumeral() Checks whether the aCharCode is an
     * alphabet or a numeric character in ASCII.
     *
     * @param aCharCode         Charcode which you want to test.
     * @return                  TRUE if aCharCode is an alphabet or a numeric
     *                          in ASCII range.  Otherwise, FALSE.
     */
    static PRBool IsBasicLatinLetterOrNumeral(PRUint32 aCharCode);

    /**
     * InitKeypressEvent() intializes keyCode, charCode and
     * alternativeCharCodes of keypress event.
     *
     * @param aKeyEvent         An NS_KEY_PRESS event, must not be NULL.
     *                          The modifier related members and keyCode must
     *                          be initialized already.
     * @param aGdkKeyEvent      A native key event which causes dispatching
     *                          aKeyEvent.
     */
    void InitKeypressEvent(nsKeyEvent& aKeyEvent, GdkEventKey* aGdkKeyEvent);
};

} // namespace widget
} // namespace mozilla

#endif /* __nsGdkKeyUtils_h__ */