michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this file,
michael@0:  * You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: 'use strict';
michael@0: 
michael@0: const Cc = Components.classes;
michael@0: const Ci = Components.interfaces;
michael@0: const Cu = Components.utils;
michael@0: const Cr = Components.results;
michael@0: 
michael@0: this.EXPORTED_SYMBOLS = ['TraversalRules'];
michael@0: 
michael@0: Cu.import('resource://gre/modules/accessibility/Utils.jsm');
michael@0: Cu.import('resource://gre/modules/XPCOMUtils.jsm');
michael@0: XPCOMUtils.defineLazyModuleGetter(this, 'Roles',
michael@0:   'resource://gre/modules/accessibility/Constants.jsm');
michael@0: XPCOMUtils.defineLazyModuleGetter(this, 'Filters',
michael@0:   'resource://gre/modules/accessibility/Constants.jsm');
michael@0: XPCOMUtils.defineLazyModuleGetter(this, 'States',
michael@0:   'resource://gre/modules/accessibility/Constants.jsm');
michael@0: XPCOMUtils.defineLazyModuleGetter(this, 'Prefilters',
michael@0:   'resource://gre/modules/accessibility/Constants.jsm');
michael@0: 
michael@0: let gSkipEmptyImages = new PrefCache('accessibility.accessfu.skip_empty_images');
michael@0: 
michael@0: function BaseTraversalRule(aRoles, aMatchFunc, aPreFilter) {
michael@0:   this._explicitMatchRoles = new Set(aRoles);
michael@0:   this._matchRoles = aRoles;
michael@0:   if (aRoles.indexOf(Roles.LABEL) < 0) {
michael@0:     this._matchRoles.push(Roles.LABEL);
michael@0:   }
michael@0:   this._matchFunc = aMatchFunc || function (acc) { return Filters.MATCH; };
michael@0:   this.preFilter = aPreFilter || gSimplePreFilter;
michael@0: }
michael@0: 
michael@0: BaseTraversalRule.prototype = {
michael@0:     getMatchRoles: function BaseTraversalRule_getmatchRoles(aRules) {
michael@0:       aRules.value = this._matchRoles;
michael@0:       return aRules.value.length;
michael@0:     },
michael@0: 
michael@0:     match: function BaseTraversalRule_match(aAccessible)
michael@0:     {
michael@0:       let role = aAccessible.role;
michael@0:       if (role == Roles.INTERNAL_FRAME) {
michael@0:         return (Utils.getMessageManager(aAccessible.DOMNode)) ?
michael@0:           Filters.MATCH  | Filters.IGNORE_SUBTREE : Filters.IGNORE;
michael@0:       }
michael@0: 
michael@0:       let matchResult = this._explicitMatchRoles.has(role) ?
michael@0:           this._matchFunc(aAccessible) : Filters.IGNORE;
michael@0: 
michael@0:       // If we are on a label that nests a checkbox/radio we should land on it.
michael@0:       // It is a bigger touch target, and it reduces clutter.
michael@0:       if (role == Roles.LABEL && !(matchResult & Filters.IGNORE_SUBTREE)) {
michael@0:         let control = Utils.getEmbeddedControl(aAccessible);
michael@0:         if (control && this._explicitMatchRoles.has(control.role)) {
michael@0:           matchResult = this._matchFunc(control) | Filters.IGNORE_SUBTREE;
michael@0:         }
michael@0:       }
michael@0: 
michael@0:       return matchResult;
michael@0:     },
michael@0: 
michael@0:     QueryInterface: XPCOMUtils.generateQI([Ci.nsIAccessibleTraversalRule])
michael@0: };
michael@0: 
michael@0: var gSimpleTraversalRoles =
michael@0:   [Roles.MENUITEM,
michael@0:    Roles.LINK,
michael@0:    Roles.PAGETAB,
michael@0:    Roles.GRAPHIC,
michael@0:    Roles.STATICTEXT,
michael@0:    Roles.TEXT_LEAF,
michael@0:    Roles.PUSHBUTTON,
michael@0:    Roles.CHECKBUTTON,
michael@0:    Roles.RADIOBUTTON,
michael@0:    Roles.COMBOBOX,
michael@0:    Roles.PROGRESSBAR,
michael@0:    Roles.BUTTONDROPDOWN,
michael@0:    Roles.BUTTONMENU,
michael@0:    Roles.CHECK_MENU_ITEM,
michael@0:    Roles.PASSWORD_TEXT,
michael@0:    Roles.RADIO_MENU_ITEM,
michael@0:    Roles.TOGGLE_BUTTON,
michael@0:    Roles.ENTRY,
michael@0:    Roles.KEY,
michael@0:    Roles.HEADER,
michael@0:    Roles.HEADING,
michael@0:    Roles.SLIDER,
michael@0:    Roles.SPINBUTTON,
michael@0:    Roles.OPTION,
michael@0:    // Used for traversing in to child OOP frames.
michael@0:    Roles.INTERNAL_FRAME];
michael@0: 
michael@0: var gSimpleMatchFunc = function gSimpleMatchFunc(aAccessible) {
michael@0:   function hasZeroOrSingleChildDescendants () {
michael@0:     for (let acc = aAccessible; acc.childCount > 0; acc = acc.firstChild) {
michael@0:       if (acc.childCount > 1) {
michael@0:         return false;
michael@0:       }
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   switch (aAccessible.role) {
michael@0:   case Roles.COMBOBOX:
michael@0:     // We don't want to ignore the subtree because this is often
michael@0:     // where the list box hangs out.
michael@0:     return Filters.MATCH;
michael@0:   case Roles.TEXT_LEAF:
michael@0:     {
michael@0:       // Nameless text leaves are boring, skip them.
michael@0:       let name = aAccessible.name;
michael@0:       if (name && name.trim())
michael@0:         return Filters.MATCH;
michael@0:       else
michael@0:         return Filters.IGNORE;
michael@0:     }
michael@0:   case Roles.STATICTEXT:
michael@0:     {
michael@0:       let parent = aAccessible.parent;
michael@0:       // Ignore prefix static text in list items. They are typically bullets or numbers.
michael@0:       if (parent.childCount > 1 && aAccessible.indexInParent == 0 &&
michael@0:           parent.role == Roles.LISTITEM)
michael@0:         return Filters.IGNORE;
michael@0: 
michael@0:       return Filters.MATCH;
michael@0:     }
michael@0:   case Roles.GRAPHIC:
michael@0:     return TraversalRules._shouldSkipImage(aAccessible);
michael@0:   case Roles.HEADER:
michael@0:   case Roles.HEADING:
michael@0:     if ((aAccessible.childCount > 0 || aAccessible.name) &&
michael@0:         hasZeroOrSingleChildDescendants()) {
michael@0:       return Filters.MATCH | Filters.IGNORE_SUBTREE;
michael@0:     } else {
michael@0:       return Filters.IGNORE;
michael@0:     }
michael@0:   default:
michael@0:     // Ignore the subtree, if there is one. So that we don't land on
michael@0:     // the same content that was already presented by its parent.
michael@0:     return Filters.MATCH |
michael@0:       Filters.IGNORE_SUBTREE;
michael@0:   }
michael@0: };
michael@0: 
michael@0: var gSimplePreFilter = Prefilters.DEFUNCT |
michael@0:   Prefilters.INVISIBLE |
michael@0:   Prefilters.ARIA_HIDDEN |
michael@0:   Prefilters.TRANSPARENT;
michael@0: 
michael@0: this.TraversalRules = {
michael@0:   Simple: new BaseTraversalRule(gSimpleTraversalRoles, gSimpleMatchFunc),
michael@0: 
michael@0:   SimpleOnScreen: new BaseTraversalRule(
michael@0:     gSimpleTraversalRoles, gSimpleMatchFunc,
michael@0:     Prefilters.DEFUNCT | Prefilters.INVISIBLE | Prefilters.ARIA_HIDDEN |
michael@0:     Prefilters.TRANSPARENT | Prefilters.OFFSCREEN),
michael@0: 
michael@0:   Anchor: new BaseTraversalRule(
michael@0:     [Roles.LINK],
michael@0:     function Anchor_match(aAccessible)
michael@0:     {
michael@0:       // We want to ignore links, only focus named anchors.
michael@0:       if (Utils.getState(aAccessible).contains(States.LINKED)) {
michael@0:         return Filters.IGNORE;
michael@0:       } else {
michael@0:         return Filters.MATCH;
michael@0:       }
michael@0:     }),
michael@0: 
michael@0:   Button: new BaseTraversalRule(
michael@0:     [Roles.PUSHBUTTON,
michael@0:      Roles.SPINBUTTON,
michael@0:      Roles.TOGGLE_BUTTON,
michael@0:      Roles.BUTTONDROPDOWN,
michael@0:      Roles.BUTTONDROPDOWNGRID]),
michael@0: 
michael@0:   Combobox: new BaseTraversalRule(
michael@0:     [Roles.COMBOBOX,
michael@0:      Roles.LISTBOX]),
michael@0: 
michael@0:   Landmark: new BaseTraversalRule(
michael@0:     [],
michael@0:     function Landmark_match(aAccessible) {
michael@0:       return Utils.getLandmarkName(aAccessible) ? Filters.MATCH :
michael@0:         Filters.IGNORE;
michael@0:     }
michael@0:   ),
michael@0: 
michael@0:   Entry: new BaseTraversalRule(
michael@0:     [Roles.ENTRY,
michael@0:      Roles.PASSWORD_TEXT]),
michael@0: 
michael@0:   FormElement: new BaseTraversalRule(
michael@0:     [Roles.PUSHBUTTON,
michael@0:      Roles.SPINBUTTON,
michael@0:      Roles.TOGGLE_BUTTON,
michael@0:      Roles.BUTTONDROPDOWN,
michael@0:      Roles.BUTTONDROPDOWNGRID,
michael@0:      Roles.COMBOBOX,
michael@0:      Roles.LISTBOX,
michael@0:      Roles.ENTRY,
michael@0:      Roles.PASSWORD_TEXT,
michael@0:      Roles.PAGETAB,
michael@0:      Roles.RADIOBUTTON,
michael@0:      Roles.RADIO_MENU_ITEM,
michael@0:      Roles.SLIDER,
michael@0:      Roles.CHECKBUTTON,
michael@0:      Roles.CHECK_MENU_ITEM]),
michael@0: 
michael@0:   Graphic: new BaseTraversalRule(
michael@0:     [Roles.GRAPHIC],
michael@0:     function Graphic_match(aAccessible) {
michael@0:       return TraversalRules._shouldSkipImage(aAccessible);
michael@0:     }),
michael@0: 
michael@0:   Heading: new BaseTraversalRule(
michael@0:     [Roles.HEADING],
michael@0:     function Heading_match(aAccessible) {
michael@0:       return aAccessible.childCount > 0 ? Filters.MATCH : Filters.IGNORE;
michael@0:     }),
michael@0: 
michael@0:   ListItem: new BaseTraversalRule(
michael@0:     [Roles.LISTITEM,
michael@0:      Roles.TERM]),
michael@0: 
michael@0:   Link: new BaseTraversalRule(
michael@0:     [Roles.LINK],
michael@0:     function Link_match(aAccessible)
michael@0:     {
michael@0:       // We want to ignore anchors, only focus real links.
michael@0:       if (Utils.getState(aAccessible).contains(States.LINKED)) {
michael@0:         return Filters.MATCH;
michael@0:       } else {
michael@0:         return Filters.IGNORE;
michael@0:       }
michael@0:     }),
michael@0: 
michael@0:   List: new BaseTraversalRule(
michael@0:     [Roles.LIST,
michael@0:      Roles.DEFINITION_LIST]),
michael@0: 
michael@0:   PageTab: new BaseTraversalRule(
michael@0:     [Roles.PAGETAB]),
michael@0: 
michael@0:   Paragraph: new BaseTraversalRule(
michael@0:     [Roles.PARAGRAPH,
michael@0:      Roles.SECTION],
michael@0:     function Paragraph_match(aAccessible) {
michael@0:       for (let child = aAccessible.firstChild; child; child = child.nextSibling) {
michael@0:         if (child.role === Roles.TEXT_LEAF) {
michael@0:           return Filters.MATCH | Filters.IGNORE_SUBTREE;
michael@0:         }
michael@0:       }
michael@0: 
michael@0:       return Filters.IGNORE;
michael@0:     }),
michael@0: 
michael@0:   RadioButton: new BaseTraversalRule(
michael@0:     [Roles.RADIOBUTTON,
michael@0:      Roles.RADIO_MENU_ITEM]),
michael@0: 
michael@0:   Separator: new BaseTraversalRule(
michael@0:     [Roles.SEPARATOR]),
michael@0: 
michael@0:   Table: new BaseTraversalRule(
michael@0:     [Roles.TABLE]),
michael@0: 
michael@0:   Checkbox: new BaseTraversalRule(
michael@0:     [Roles.CHECKBUTTON,
michael@0:      Roles.CHECK_MENU_ITEM]),
michael@0: 
michael@0:   _shouldSkipImage: function _shouldSkipImage(aAccessible) {
michael@0:     if (gSkipEmptyImages.value && aAccessible.name === '') {
michael@0:       return Filters.IGNORE;
michael@0:     }
michael@0:     return Filters.MATCH;
michael@0:   }
michael@0: };