Proyectos de Subversion Moodle

// This file is part of Moodle - http://moodle.org/

//

// Moodle 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 3 of the License, or

// (at your option) any later version.

//

// Moodle 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 General Public License

// along with Moodle.  If not, see <http://www.gnu.org/licenses/>.

/**

 * @module moodle-editor_atto-plugin

 * @submodule buttons

 */

/**

 * Button functions for an Atto Plugin.

 *

 * See {{#crossLink "M.editor_atto.EditorPlugin"}}{{/crossLink}} for details.

 *

 * @namespace M.editor_atto

 * @class EditorPluginButtons

 */

var MENUTEMPLATE = '' +

        '<button class="{{buttonClass}} atto_hasmenu" ' +

            'id="{{id}}" ' +

            'tabindex="-1" ' +

            'title="{{title}}" ' +

            'aria-label="{{title}}" ' +

            'type="button" ' +

            'aria-haspopup="true" ' +

            'aria-controls="{{id}}_menu">' +

            '<span class="editor_atto_menu_icon"></span>' +

            '<span class="editor_atto_menu_expand"></span>' +

        '</button>';

var DISABLED = 'disabled',

    HIGHLIGHT = 'highlight',

    LOGNAME = 'moodle-editor_atto-editor-plugin',

    CSS = {

        EDITORWRAPPER: '.editor_atto_content',

        MENUICON: '.editor_atto_menu_icon',

        MENUEXPAND: '.editor_atto_menu_expand'

    };

function EditorPluginButtons() {}

EditorPluginButtons.ATTRS = {

};

EditorPluginButtons.prototype = {

    /**

     * All of the buttons that belong to this plugin instance.

     *

     * Buttons are stored by button name.

     *

     * @property buttons

     * @type object

     */

    buttons: null,

    /**

     * A list of each of the button names.

     *

     * @property buttonNames

     * @type array

     */

    buttonNames: null,

    /**

     * A read-only view of the current state for each button. Mappings are stored by name.

     *

     * Possible states are:

     * <ul>

     * <li>{{#crossLink "M.editor_atto.EditorPluginButtons/ENABLED:property"}}{{/crossLink}}; and</li>

     * <li>{{#crossLink "M.editor_atto.EditorPluginButtons/DISABLED:property"}}{{/crossLink}}.</li>

     * </ul>

     *

     * @property buttonStates

     * @type object

     */

    buttonStates: null,

    /**

     * The menus belonging to this plugin instance.

     *

     * @property menus

     * @type object

     */

    menus: null,

    /**

     * The state for a disabled button.

     *

     * @property DISABLED

     * @type Number

     * @static

     * @value 0

     */

    DISABLED: 0,

    /**

     * The state for an enabled button.

     *

     * @property ENABLED

     * @type Number

     * @static

     * @value 1

     */

    ENABLED: 1,

    /**

     * The list of Event Handlers for buttons.

     *

     * @property _buttonHandlers

     * @protected

     * @type array

     */

    _buttonHandlers: null,

    /**

     * Hide handlers which are cancelled when the menu is hidden.

     *

     * @property _menuHideHandlers

     * @protected

     * @type array

     */

    _menuHideHandlers: null,

    /**

     * A textual description of the primary keyboard shortcut for this

     * plugin.

     *

     * This will be null if no keyboard shortcut has been registered.

     *

     * @property _primaryKeyboardShortcut

     * @protected

     * @type String

     * @default null

     */

    _primaryKeyboardShortcut: null,

    /**

     * An list of objects returned by Y.soon().

     *

     * The keys will be the buttonName of the button, and the value the Y.soon() object.

     *

     * @property _highlightQueue

     * @protected

     * @type Object

     * @default null

     */

    _highlightQueue: null,

    /**

     * Add a button for this plugin to the toolbar.

     *

     * @method addButton

     * @param {object} config The configuration for this button

     * @param {string} [config.iconurl] The URL for the icon. If not specified, then the icon and component will be used instead.

     * @param {string} [config.icon] The icon identifier.

     * @param {string} [config.iconComponent='core'] The icon component.

     * @param {string} [config.keys] The shortcut key that can call this plugin from the keyboard.

     * @param {string} [config.keyDescription] An optional description for the keyboard shortcuts.

     * If not specified, this is automatically generated based on config.keys.

     * If multiple key bindings are supplied to config.keys, then only the first is used.

     * If set to false, then no description is added to the title.

     * @param {string} [config.tags] The tags that trigger this button to be highlighted.

     * @param {boolean} [config.tagMatchRequiresAll=true] Working in combination with the tags parameter, when true

     * every tag of the selection has to match. When false, only one match is needed. Only set this to false when

     * necessary as it is much less efficient.

     * See {{#crossLink "M.editor_atto.EditorSelection/selectionFilterMatches:method"}}{{/crossLink}} for more information.

     * @param {string} [config.title=this.name] The string identifier in the plugin's language file.

     * @param {string} [config.buttonName=this.name] The name of the button. This is used in the buttons object, and if

     * specified, in the class for the button.

     * @param {function} config.callback A callback function to call when the button is clicked.

     * @param {object} [config.callbackArgs] Any arguments to pass to the callback.

     * @param {boolean} [config.inlineFormat] Delay callback for text input if selection is collapsed.

     * @return {Node} The Node representing the newly created button.

     */

    addButton: function(config) {

        var group = this.get('group'),

            pluginname = this.name,

            buttonClass = 'atto_' + pluginname + '_button',

            button,

            host = this.get('host');

        if (config.exec) {

            buttonClass = buttonClass + '_' + config.exec;

        }

        if (!config.buttonName) {

            // Set a default button name - this is used as an identifier in the button object.

            config.buttonName = config.exec || pluginname;

        } else {

            buttonClass = buttonClass + '_' + config.buttonName;

        }

        config.buttonClass = buttonClass;

        // Normalize icon configuration.

        config = this._normalizeIcon(config);

        if (!config.title) {

            config.title = 'pluginname';

        }

        var title = M.util.get_string(config.title, 'atto_' + pluginname);

        // Create the actual button.

        button = Y.Node.create('<button type="button" class="' + buttonClass + '"' +

                'tabindex="-1"></button>');

        button.setAttribute('title', title);

        button.setAttribute('aria-label', title);

        window.require(['core/templates'], function(Templates) {

            // The button already has title and label, so no need to set them again on the icon.

            Templates.renderPix(config.icon, config.iconComponent, '').then(function(iconhtml) {

                button.append(iconhtml);

            });

        });

        // Append it to the group.

        group.append(button);

        var currentfocus = this.toolbar.getAttribute('aria-activedescendant');

        if (!currentfocus) {

            // Initially set the first button in the toolbar to be the default on keyboard focus.

            button.setAttribute('tabindex', '0');

            this.toolbar.setAttribute('aria-activedescendant', button.generateID());

            this.get('host')._tabFocus = button;

        }

        // Normalize the callback parameters.

        config = this._normalizeCallback(config);

        // Add the standard click handler to the button.

        this._buttonHandlers.push(

            this.toolbar.delegate('click', config.callback, '.' + buttonClass, this)

        );

        // Handle button click via shortcut key.

        if (config.keys) {

            if (typeof config.keyDescription !== 'undefined') {

                // A keyboard shortcut description was specified - use it.

                this._primaryKeyboardShortcut[buttonClass] = config.keyDescription;

            }

            this._addKeyboardListener(config.callback, config.keys, buttonClass);

            if (this._primaryKeyboardShortcut[buttonClass]) {

                // If we have a valid keyboard shortcut description, then set it with the title.

                title = M.util.get_string('plugin_title_shortcut', 'editor_atto', {

                    title: title,

                    shortcut: this._primaryKeyboardShortcut[buttonClass]

                });

                button.setAttribute('title', title);

                button.setAttribute('aria-label', title);

            }

        }

        // Handle highlighting of the button.

        if (config.tags) {

            var tagMatchRequiresAll = true;

            if (typeof config.tagMatchRequiresAll === 'boolean') {

                tagMatchRequiresAll = config.tagMatchRequiresAll;

            }

            this._buttonHandlers.push(

                host.on(['atto:selectionchanged', 'change'], function(e) {

                    if (typeof this._highlightQueue[config.buttonName] !== 'undefined') {

                        this._highlightQueue[config.buttonName].cancel();

                    }

                    // Async the highlighting.

                    this._highlightQueue[config.buttonName] = Y.soon(Y.bind(function(e) {

                        if (host.selectionFilterMatches(config.tags, e.selectedNodes, tagMatchRequiresAll)) {

                            this.highlightButtons(config.buttonName);

                        } else {

                            this.unHighlightButtons(config.buttonName);

                        }

                    }, this, e));

                }, this)

            );

        }

        // Add the button reference to the buttons array for later reference.

        this.buttonNames.push(config.buttonName);

        this.buttons[config.buttonName] = button;

        this.buttonStates[config.buttonName] = this.ENABLED;

        return button;

    },

    /**

     * Add a basic button which ties into the execCommand.

     *

     * See {{#crossLink "M.editor_atto.EditorPluginButtons/addButton:method"}}addButton{{/crossLink}}

     * for full details of the optional parameters.

     *

     * @method addBasicButton

     * @param {object} config The button configuration

     * @param {string} config.exec The execCommand to call on the document.

     * @param {string} [config.iconurl] The URL for the icon. If not specified, then the icon and component will be used instead.

     * @param {string} [config.icon] The icon identifier.

     * @param {string} [config.iconComponent='core'] The icon component.

     * @param {string} [config.keys] The shortcut key that can call this plugin from the keyboard.

     * @param {string} [config.tags] The tags that trigger this button to be highlighted.

     * @param {boolean} [config.tagMatchRequiresAll=false] Working in combination with the tags parameter, highlight

     * this button when any match is good enough.

     *

     * See {{#crossLink "M.editor_atto.EditorSelection/selectionFilterMatches:method"}}{{/crossLink}} for more information.

     * @param {string} [config.title=this.name] The string identifier in the plugin's language file.

     * @param {string} [config.buttonName=this.name] The name of the button. This is used in the buttons object, and if

     * specified, in the class for the button.

     * @return {Node} The Node representing the newly created button.

     */

    addBasicButton: function(config) {

        if (!config.exec) {

            Y.log('No exec command specified. Cannot proceed.',

                    'warn', 'moodle-editor_atto-plugin');

            return null;

        }

        // The default icon - true for most core plugins.

        if (!config.icon) {

            config.icon = 'e/' + config.exec;

        }

        // The default callback.

        config.callback = function() {

            document.execCommand(config.exec, false, null);

            // And mark the text area as updated.

            this.markUpdated();

        };

        // Return the newly created button.

        return this.addButton(config);

    },

    /**

     * Add a menu for this plugin to the editor toolbar.

     *

     * @method addToolbarMenu

     * @param {object} config The configuration for this button

     * @param {string} [config.iconurl] The URL for the icon. If not specified, then the icon and component will be used instead.

     * @param {string} [config.icon] The icon identifier.

     * @param {string} [config.iconComponent='core'] The icon component.

     * @param {string} [config.title=this.name] The string identifier in the plugin's language file.

     * @param {string} [config.buttonName=this.name] The name of the button. This is used in the buttons object, and if

     * specified, in the class for the button.

     * @param {function} config.callback A callback function to call when the button is clicked.

     * @param {object} [config.callbackArgs] Any arguments to pass to the callback.

     * @param {boolean} [config.inlineFormat] Delay callback for text input if selection is collapsed.

     * @param {array} config.entries List of menu entries with the string (entry.text) and the handlers (entry.handler).

     * @param {number} [config.overlayWidth=14] The width of the menu. This will be suffixed with the 'em' unit.

     * @param {string} [config.menuColor] menu icon background color

     * @return {Node} The Node representing the newly created button.

     */

    addToolbarMenu: function(config) {

        var group = this.get('group'),

            pluginname = this.name,

            buttonClass = 'atto_' + pluginname + '_button',

            button,

            currentFocus;

        if (!config.buttonName) {

            // Set a default button name - this is used as an identifier in the button object.

            config.buttonName = pluginname;

        } else {

            buttonClass = buttonClass + '_' + config.buttonName;

        }

        config.buttonClass = buttonClass;

        // Normalize icon configuration.

        config = this._normalizeIcon(config);

        if (!config.title) {

            config.title = 'pluginname';

        }

        var title = M.util.get_string(config.title, 'atto_' + pluginname);

        if (!config.menuColor) {

            config.menuColor = 'transparent';

        }

        // Create the actual button.

        var id = 'atto_' + pluginname + '_menubutton_' + Y.stamp(this);

        var template = Y.Handlebars.compile(MENUTEMPLATE);

        button = Y.Node.create(template({

            buttonClass: buttonClass,

            config: config,

            title: title,

            id: id

        }));

        // Add this button id to the config. It will be used in the menu later.

        config.buttonId = id;

        window.require(['core/templates'], function(Templates) {

            // The button already has title and label, so no need to set them again on the icon.

            Templates.renderPix(config.icon, config.iconComponent, '').then(function(iconhtml) {

                button.one(CSS.MENUICON).append(iconhtml);

            });

            Templates.renderPix('t/expanded', 'core', '').then(function(iconhtml) {

                button.one(CSS.MENUEXPAND).append(iconhtml);

            });

        });

        // Append it to the group.

        group.append(button);

        group.append(Y.Node.create('<div class="menuplaceholder" id="' + id + '_menu"></div>'));

        config.attachmentPoint = '#' + id + '_menu';

        currentFocus = this.toolbar.getAttribute('aria-activedescendant');

        if (!currentFocus) {

            // Initially set the first button in the toolbar to be the default on keyboard focus.

            button.setAttribute('tabindex', '0');

            this.toolbar.setAttribute('aria-activedescendant', button.generateID());

        }

        // Add the standard click handler to the menu.

        this._buttonHandlers.push(

            this.toolbar.delegate('click', this._showToolbarMenu, '.' + buttonClass, this, config),

            this.toolbar.delegate('key', this._showToolbarMenuAndFocus, '40, 32, enter', '.' + buttonClass, this, config)

        );

        // Add the button reference to the buttons array for later reference.

        this.buttonNames.push(config.buttonName);

        this.buttons[config.buttonName] = button;

        this.buttonStates[config.buttonName] = this.ENABLED;

        return button;

    },

    /**

     * Display a toolbar menu.

     *

     * @method _showToolbarMenu

     * @param {EventFacade} e

     * @param {object} config The configuration for the whole toolbar.

     * @param {Number} [config.overlayWidth=14] The width of the menu

     * @private

     */

    _showToolbarMenu: function(e, config) {

        // Prevent default primarily to prevent arrow press changes.

        e.preventDefault();

        if (!this.isEnabled()) {

            // Exit early if the plugin is disabled.

            return;

        }

        // Ensure menu button was clicked, and isn't itself disabled.

        var menuButton = e.currentTarget.ancestor('button', true);

        if (menuButton === null || menuButton.hasAttribute(DISABLED)) {

            return;

        }

        var menuDialogue;

        if (!this.menus[config.buttonClass]) {

            if (!config.overlayWidth) {

                config.overlayWidth = '14';

            }

            if (!config.innerOverlayWidth) {

                config.innerOverlayWidth = parseInt(config.overlayWidth, 10) - 2 + 'em';

            }

            config.overlayWidth = parseInt(config.overlayWidth, 10) + 'em';

            this.menus[config.buttonClass] = new Y.M.editor_atto.Menu(config);

            this.menus[config.buttonClass].get('contentBox').delegate('click',

                    this._chooseMenuItem, '.atto_menuentry a', this, config);

        }

        // Clear the focusAfterHide for any other menus which may be open.

        Y.Array.each(this.get('host').openMenus, function(menu) {

            menu.set('focusAfterHide', null);

        });

        // Ensure that we focus on this button next time.

        var creatorButton = this.buttons[config.buttonName];

        creatorButton.focus();

        this.get('host')._setTabFocus(creatorButton);

        // Get a reference to the menu dialogue.

        menuDialogue = this.menus[config.buttonClass];

        // Focus on the button by default after hiding this menu.

        menuDialogue.set('focusAfterHide', creatorButton);

        // Display the menu.

        menuDialogue.show();

        // Indicate that the menu is expanded.

        menuButton.setAttribute("aria-expanded", true);

        // Position it next to the button which opened it.

        menuDialogue.align(this.buttons[config.buttonName], [Y.WidgetPositionAlign.TL, Y.WidgetPositionAlign.BL]);

        this.get('host').openMenus = [menuDialogue];

    },

    /**

     * Display a toolbar menu and focus upon the first item.

     *

     * @method _showToolbarMenuAndFocus

     * @param {EventFacade} e

     * @param {object} config The configuration for the whole toolbar.

     * @param {Number} [config.overlayWidth=14] The width of the menu

     * @private

     */

    _showToolbarMenuAndFocus: function(e, config) {

        this._showToolbarMenu(e, config);

        // Focus on the first element in the menu.

        this.menus[config.buttonClass].get('boundingBox').one('a').focus();

    },

    /**

     * Select a menu item and call the appropriate callbacks.

     *

     * @method _chooseMenuItem

     * @param {EventFacade} e

     * @param {object} config

     * @param {M.core.dialogue} menuDialogue The Dialogue to hide.

     * @private

     */

    _chooseMenuItem: function(e, config, menuDialogue) {

        // Get the index from the clicked anchor.

        var index = e.target.ancestor('a', true).getData('index'),

            // And the normalized callback configuration.

            buttonConfig = this._normalizeCallback(config.items[index], config.globalItemConfig);

            menuDialogue = this.menus[config.buttonClass];

        // Prevent the dialogue to be closed because of some browser weirdness.

        menuDialogue.set('preventHideMenu', true);

        // Call the callback for this button.

        buttonConfig.callback(e, buttonConfig._callback, buttonConfig.callbackArgs);

        // Cancel the hide menu prevention.

        menuDialogue.set('preventHideMenu', false);

        // Set the focus after hide so that focus is returned to the editor and changes are made correctly.

        menuDialogue.set('focusAfterHide', this.get('host').editor);

        menuDialogue.hide(e);

    },

    /**

     * Normalize and sanitize the configuration variables relating to callbacks.

     *

     * @method _normalizeCallback

     * @param {object} config

     * @param {function} config.callback A callback function to call when the button is clicked.

     * @param {object} [config.callbackArgs] Any arguments to pass to the callback.

     * @param {boolean} [config.inlineFormat] Delay callback for text input if selection is collapsed.

     * @param {object} [inheritFrom] A parent configuration that this configuration may inherit from.

     * @return {object} The normalized configuration

     * @private

     */

    _normalizeCallback: function(config, inheritFrom) {

        if (config._callbackNormalized) {

            // Return early if the callback has already been normalized.

            return config;

        }

        if (!inheritFrom) {

            // Create an empty inheritFrom to make life easier below.

            inheritFrom = {};

        }

        // First we wrap the callback in function to handle formating of text inserted into collapsed selection.

        config.inlineFormat = config.inlineFormat || inheritFrom.inlineFormat;

        config._inlineCallback = config.callback || inheritFrom.callback;

        config._callback = config.callback || inheritFrom.callback;

        if (config.inlineFormat && typeof config._inlineCallback === 'function') {

            config._callback = function(e, args) {

                this.get('host').applyFormat(e, config._inlineCallback, this, args);

            };

        }

        // We wrap the callback in function to prevent the default action, check whether the editor is

        // active and focus it, and then mark the field as updated.

        config.callback = Y.rbind(this._callbackWrapper, this, config._callback, config.callbackArgs);

        config._callbackNormalized = true;

        return config;

    },

    /**

     * Normalize and sanitize the configuration variables relating to icons.

     *

     * @method _normalizeIcon

     * @param {object} config

     * @param {string} [config.iconurl] The URL for the icon. If not specified, then the icon and component will be used instead.

     * @param {string} [config.icon] The icon identifier.

     * @param {string} [config.iconComponent='core'] The icon component.

     * @return {object} The normalized configuration

     * @private

     */

    _normalizeIcon: function(config) {

        if (!config.iconurl) {

            // The default icon component.

            if (!config.iconComponent || config.iconComponent == 'moodle') {

                config.iconComponent = 'core';

            }

            config.iconurl = M.util.image_url(config.icon, config.iconComponent);

        }

        return config;

    },

    /**

     * A wrapper in which to run the callbacks.

     *

     * This handles common functionality such as:

     * <ul>

     *  <li>preventing the default action; and</li>

     *  <li>focusing the editor if relevant.</li>

     * </ul>

     *

     * @method _callbackWrapper

     * @param {EventFacade} e

     * @param {Function} callback The function to call which makes the relevant changes.

     * @param {Array} [callbackArgs] The arguments passed to this callback.

     * @return {Mixed} The value returned by the callback.

     * @private

     */

    _callbackWrapper: function(e, callback, callbackArgs) {

        e.preventDefault();

        if (!this.isEnabled()) {

            // Exit early if the plugin is disabled.

            return;

        }

        var creatorButton = e.currentTarget.ancestor('button', true);

        if (creatorButton && creatorButton.hasAttribute(DISABLED)) {

            // Exit early if the clicked button was disabled.

            return;

        }

        if (!(YUI.Env.UA.android || this.get('host').isActive())) {

            // We must not focus for Android here, even if the editor is not active because the keyboard auto-completion

            // changes the cursor position.

            // If we save that change, then when we restore the change later we get put in the wrong place.

            // Android is fine to save the selection without the editor being in focus.

            this.get('host').focus();

        }

        // Save the selection.

        this.get('host').saveSelection();

        // Ensure that we focus on this button next time.

        if (creatorButton) {

            this.get('host')._setTabFocus(creatorButton);

        }

        // Build the arguments list, but remove the callback we're calling.

        var args = [e, callbackArgs];

        // Restore selection before making changes.

        this.get('host').restoreSelection();

        // Actually call the callback now.

        return callback.apply(this, args);

    },

    /**

     * Add a keyboard listener to call the callback.

     *

     * The keyConfig will take either an array of keyConfigurations, in

     * which case _addKeyboardListener is called multiple times; an object

     * containing an optional eventtype, optional container, and a set of

     * keyCodes, or just a string containing the keyCodes. When keyConfig is

     * not an object, it is wrapped around a function that ensures that

     * only the expected key modifiers were used. For instance, it checks

     * that space+ctrl is not triggered when the user presses ctrl+shift+space.

     * When using an object, the developer should check that manually.

     *

     * @method _addKeyboardListener

     * @param {function} callback

     * @param {array|object|string} keyConfig

     * @param {string} [keyConfig.eventtype=key] The type of event

     * @param {string} [keyConfig.container=.editor_atto_content] The containing element.

     * @param {string} keyConfig.keyCodes The keycodes to user for the event.

     * @private

     *

     */

    _addKeyboardListener: function(callback, keyConfig, buttonName) {

        var eventtype = 'key',

            container = CSS.EDITORWRAPPER,

            keys,

            handler,

            modifier;

        if (Y.Lang.isArray(keyConfig)) {

            // If an Array was specified, call the add function for each element.

            Y.Array.each(keyConfig, function(config) {

                this._addKeyboardListener(callback, config);

            }, this);

            return this;

        } else if (typeof keyConfig === "object") {

            if (keyConfig.eventtype) {

                eventtype = keyConfig.eventtype;

            }

            if (keyConfig.container) {

                container = keyConfig.container;

            }

            // Must be specified.

            keys = keyConfig.keyCodes;

            handler = callback;

        } else {

            modifier = this._getDefaultMetaKey();

            keys = this._getKeyEvent() + keyConfig + '+' + modifier;

            if (typeof this._primaryKeyboardShortcut[buttonName] === 'undefined') {

                this._primaryKeyboardShortcut[buttonName] = this._getDefaultMetaKeyDescription(keyConfig);

            }

            // Wrap the callback into a handler to check if it uses the specified modifiers, not more.

            handler = Y.bind(function(modifiers, e) {

                if (this._eventUsesExactKeyModifiers(modifiers, e)) {

                    callback.apply(this, [e]);

                }

            }, this, [modifier]);

        }

        this._buttonHandlers.push(

            this.editor.delegate(

                eventtype,

                handler,

                keys,

                container,

                this

            )

        );

        Y.log('Atto shortcut registered: ' + keys + ' now triggers for ' + buttonName,

                'debug', LOGNAME);

    },

    /**

     * Checks if a key event was strictly defined for the modifiers passed.

     *

     * @method _eventUsesExactKeyModifiers

     * @param  {Array} modifiers List of key modifiers to check for (alt, ctrl, meta or shift).

     * @param  {EventFacade} e The event facade.

     * @return {Boolean} True if the event was stricly using the modifiers specified.

     */

    _eventUsesExactKeyModifiers: function(modifiers, e) {

        var exactMatch = true,

            hasKey;

        if (e.type !== 'key') {

            return false;

        }

        hasKey = Y.Array.indexOf(modifiers, 'alt') > -1;

        exactMatch = exactMatch && ((e.altKey && hasKey) || (!e.altKey && !hasKey));

        hasKey = Y.Array.indexOf(modifiers, 'ctrl') > -1;

        exactMatch = exactMatch && ((e.ctrlKey && hasKey) || (!e.ctrlKey && !hasKey));

        hasKey = Y.Array.indexOf(modifiers, 'meta') > -1;

        exactMatch = exactMatch && ((e.metaKey && hasKey) || (!e.metaKey && !hasKey));

        hasKey = Y.Array.indexOf(modifiers, 'shift') > -1;

        exactMatch = exactMatch && ((e.shiftKey && hasKey) || (!e.shiftKey && !hasKey));

        return exactMatch;

    },

    /**

     * Determine if this plugin is enabled, based upon the state of it's buttons.

     *

     * @method isEnabled

     * @return {boolean}

     */

    isEnabled: function() {

        // The first instance of an undisabled button will make this return true.

        var found = Y.Object.some(this.buttonStates, function(button) {

            return (button === this.ENABLED);

        }, this);

        return found;

    },

    /**

     * Enable one button, or all buttons relating to this Plugin.

     *

     * If no button is specified, all buttons are disabled.

     *

     * @method disableButtons

     * @param {String} [button] The name of a specific plugin to enable.

     * @chainable

     */

    disableButtons: function(button) {

        return this._setButtonState(false, button);

    },

    /**

     * Enable one button, or all buttons relating to this Plugin.

     *

     * If no button is specified, all buttons are enabled.

     *

     * @method enableButtons

     * @param {String} [button] The name of a specific plugin to enable.

     * @chainable

     */

    enableButtons: function(button) {

        return this._setButtonState(true, button);

    },

    /**

     * Set the button state for one button, or all buttons associated with this plugin.

     *

     * @method _setButtonState

     * @param {Boolean} enable Whether to enable this button.

     * @param {String} [button] The name of a specific plugin to set state for.

     * @chainable

     * @private

     */

    _setButtonState: function(enable, button) {

        var attributeChange = 'setAttribute';

        if (enable) {

            attributeChange = 'removeAttribute';

        }

        if (button) {

            if (this.buttons[button]) {

                this.buttons[button][attributeChange](DISABLED, DISABLED);

                this.buttonStates[button] = enable ? this.ENABLED : this.DISABLED;

            }

        } else {

            Y.Array.each(this.buttonNames, function(button) {

                this.buttons[button][attributeChange](DISABLED, DISABLED);

                this.buttonStates[button] = enable ? this.ENABLED : this.DISABLED;

            }, this);

        }

        this.get('host').checkTabFocus();

        return this;

    },

    /**

     * Highlight a button, or buttons in the toolbar.

     *

     * If no button is specified, all buttons are highlighted.

     *

     * @method highlightButtons

     * @param {string} [button] If a plugin has multiple buttons, the specific button to highlight.

     * @chainable

     */

    highlightButtons: function(button) {

        return this._changeButtonHighlight(true, button);

    },

    /**

     * Un-highlight a button, or buttons in the toolbar.

     *

     * If no button is specified, all buttons are un-highlighted.

     *

     * @method unHighlightButtons

     * @param {string} [button] If a plugin has multiple buttons, the specific button to highlight.

     * @chainable

     */

    unHighlightButtons: function(button) {

        return this._changeButtonHighlight(false, button);

    },

    /**

     * Highlight a button, or buttons in the toolbar.

     *

     * @method _changeButtonHighlight

     * @param {boolean} highlight true

     * @param {string} [button] If a plugin has multiple buttons, the specific button to highlight.

     * @protected

     * @chainable

     */

    _changeButtonHighlight: function(highlight, button) {

        var method = 'addClass';

        if (!highlight) {

            method = 'removeClass';

        }

        if (button) {

            if (this.buttons[button]) {

                this.buttons[button][method](HIGHLIGHT);

                this.buttons[button].setAttribute('aria-pressed', highlight ? 'true' : 'false');

                this._buttonHighlightToggled(button, highlight);

            }

        } else {

            Y.Object.each(this.buttons, function(button) {

                button[method](HIGHLIGHT);

                button.setAttribute('aria-pressed', highlight ? 'true' : 'false');

                this._buttonHighlightToggled(button, highlight);

            }, this);

        }

        return this;

    },

    /**

     * Fires a custom event that notifies listeners that a button's highlight has been toggled.

     *

     * @param {String} buttonName The button name.

     * @param {Boolean} highlight True when the button was highlighted. False, otherwise.

     * @private

     */

    _buttonHighlightToggled: function(buttonName, highlight) {

        var toggledButton = this.buttons[buttonName];

        if (toggledButton) {

            // Fire an event that the button highlight was toggled.

            require(['editor_atto/events'], function(attoEvents) {

                attoEvents.notifyButtonHighlightToggled(toggledButton.getDOMNode(), buttonName, highlight);

            });

        }

    },

    /**

     * Get the default meta key to use with keyboard events.

     *

     * On a Mac, this will be the 'meta' key for Command; otherwise it will

     * be the Control key.

     *

     * @method _getDefaultMetaKey

     * @return {string}

     * @private

     */

    _getDefaultMetaKey: function() {

        if (Y.UA.os === 'macintosh') {

            return 'meta';

        } else {

            return 'ctrl';

        }

    },

    /**

     * Get the user-visible description of the meta key to use with keyboard events.

     *

     * On a Mac, this will be 'Command' ; otherwise it will be 'Control'.

     *

     * @method _getDefaultMetaKeyDescription

     * @return {string}

     * @private

     */

    _getDefaultMetaKeyDescription: function(keyCode) {

        if (Y.UA.os === 'macintosh') {

            return M.util.get_string('editor_command_keycode', 'editor_atto', String.fromCharCode(keyCode).toLowerCase());

        } else {

            return M.util.get_string('editor_control_keycode', 'editor_atto', String.fromCharCode(keyCode).toLowerCase());

        }

    },

    /**

     * Get the standard key event to use for keyboard events.

     *

     * @method _getKeyEvent

     * @return {string}

     * @private

     */

    _getKeyEvent: function() {

        return 'down:';

    }

};

Y.Base.mix(Y.M.editor_atto.EditorPlugin, [EditorPluginButtons]);