devtools/client/accessibility/provider.js

   1 /* This Source Code Form is subject to the terms of the Mozilla Public
   2  * License, v. 2.0. If a copy of the MPL was not distributed with this
   3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   4 "use strict";
   5
   6 const {
   7   fetchChildren,
   8 } = require("resource://devtools/client/accessibility/actions/accessibles.js");
   9
  10 /**
  11  * Data provider that is responsible for mapping of an accessibles cache to the
  12  * data format that is supported by the TreeView component.
  13  * @param {Map}      accessibles accessibles object cache
  14  * @param {Function} dispatch    react dispatch function that triggers a redux
  15  *                               action.
  16  */
  17
  18 class Provider {
  19   constructor(accessibles, filtered, dispatch) {
  20     this.accessibles = accessibles;
  21     this.filtered = filtered;
  22     this.dispatch = dispatch;
  23   }
  24
  25   /**
  26    * Get accessible's cached children if available, if not fetch them from
  27    * backend.
  28    * @param {Object}  accessible accessible object whose children to get.
  29    * @returns {Array} arraof of accessible children.
  30    */
  31   getChildren(accessible) {
  32     if (!accessible || !accessible.actorID || accessible.childCount === 0) {
  33       return [];
  34     }
  35
  36     const obj = this.accessibles.get(accessible.actorID);
  37     if (!obj || !obj.children) {
  38       return this.dispatch(fetchChildren(accessible));
  39     }
  40
  41     return obj.children;
  42   }
  43
  44   /**
  45    * Return a flag indicating if an accessible object has any children.
  46    * @param {Object}    accessible accessible object whose children to get.
  47    * @returns {Boolean} idicator of whether accessible object has children.
  48    */
  49   hasChildren(accessible) {
  50     return accessible.childCount > 0;
  51   }
  52
  53   /**
  54    * Get a value for an accessible object. Used to render the second (value)
  55    * column of the accessible tree. Corresponds to an accesible object name, if
  56    * available.
  57    * @param {Object}   accessible accessible object
  58    * @returns {String} accessible object value.
  59    */
  60   getValue(accessible) {
  61     return accessible.name || "";
  62   }
  63
  64   /**
  65    * Get a label for an accessible object. Used to render the first column of
  66    * the accessible tree. Corresponds to an accessible object role.
  67    * @param {Object}   accessible accessible object
  68    * @returns {String} accessible object label.
  69    */
  70   getLabel(accessible) {
  71     return accessible.role;
  72   }
  73
  74   /**
  75    * Get a unique key for an accessible object. Corresponds to an accessible
  76    * front's actorID.
  77    * @param {Object}   accessible accessible object
  78    * @returns {String} a key for an accessible object.
  79    */
  80   getKey(accessible) {
  81     return accessible.actorID;
  82   }
  83
  84   /**
  85    * Get a type of an accesible object. Corresponds to the type of an accessible
  86    * front.
  87    * @param {Object}   accessible accessible object
  88    * @returns {String} accessible object type
  89    */
  90   getType(accessible) {
  91     return accessible.typeName;
  92   }
  93
  94   /**
  95    * Get the depth of the accesible object in the accessibility tree. When the
  96    * tree is filtered it is flattened and the level is set to 0. Otherwise use
  97    * internal TreeView level.
  98    *
  99    * @param {Object}   accessible
 100    *                   accessible object
 101    * @param {Number}   defaultLevel
 102    *                   default level provided by the TreeView component.
 103    *
 104    * @returns {null|Number}
 105    *          depth level of the accessible object.
 106    */
 107   getLevel(accessible, defaultLevel) {
 108     return this.filtered ? 0 : defaultLevel;
 109   }
 110 }
 111
 112 exports.Provider = Provider;