Add an exponential backoff to rechecking the app list doodle.

[chromium-blink-merge.git] / third_party / polymer / components-chromium / core-a11y-keys / core-a11y-keys-extracted.js

  (function() {
    /*
     * Chrome uses an older version of DOM Level 3 Keyboard Events
     *
     * Most keys are labeled as text, but some are Unicode codepoints.
     * Values taken from: http://www.w3.org/TR/2007/WD-DOM-Level-3-Events-20071221/keyset.html#KeySet-Set
     */
    var KEY_IDENTIFIER = {
      'U+0009': 'tab',
      'U+001B': 'esc',
      'U+0020': 'space',
      'U+002A': '*',
      'U+0030': '0',
      'U+0031': '1',
      'U+0032': '2',
      'U+0033': '3',
      'U+0034': '4',
      'U+0035': '5',
      'U+0036': '6',
      'U+0037': '7',
      'U+0038': '8',
      'U+0039': '9',
      'U+0041': 'a',
      'U+0042': 'b',
      'U+0043': 'c',
      'U+0044': 'd',
      'U+0045': 'e',
      'U+0046': 'f',
      'U+0047': 'g',
      'U+0048': 'h',
      'U+0049': 'i',
      'U+004A': 'j',
      'U+004B': 'k',
      'U+004C': 'l',
      'U+004D': 'm',
      'U+004E': 'n',
      'U+004F': 'o',
      'U+0050': 'p',
      'U+0051': 'q',
      'U+0052': 'r',
      'U+0053': 's',
      'U+0054': 't',
      'U+0055': 'u',
      'U+0056': 'v',
      'U+0057': 'w',
      'U+0058': 'x',
      'U+0059': 'y',
      'U+005A': 'z',
      'U+007F': 'del'
    };

    /*
     * Special table for KeyboardEvent.keyCode.
     * KeyboardEvent.keyIdentifier is better, and KeyBoardEvent.key is even better than that
     *
     * Values from: https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent.keyCode#Value_of_keyCode
     */
    var KEY_CODE = {
      9: 'tab',
      13: 'enter',
      27: 'esc',
      33: 'pageup',
      34: 'pagedown',
      35: 'end',
      36: 'home',
      32: 'space',
      37: 'left',
      38: 'up',
      39: 'right',
      40: 'down',
      46: 'del',
      106: '*'
    };

    /*
     * KeyboardEvent.key is mostly represented by printable character made by the keyboard, with unprintable keys labeled
     * nicely.
     *
     * However, on OS X, Alt+char can make a Unicode character that follows an Apple-specific mapping. In this case, we
     * fall back to .keyCode.
     */
    var KEY_CHAR = /[a-z0-9*]/;

    function transformKey(key) {
      var validKey = '';
      if (key) {
        var lKey = key.toLowerCase();
        if (lKey.length == 1) {
          if (KEY_CHAR.test(lKey)) {
            validKey = lKey;
          }
        } else if (lKey == 'multiply') {
          // numpad '*' can map to Multiply on IE/Windows
          validKey = '*';
        } else {
          validKey = lKey;
        }
      }
      return validKey;
    }

    var IDENT_CHAR = /U\+/;
    function transformKeyIdentifier(keyIdent) {
      var validKey = '';
      if (keyIdent) {
        if (IDENT_CHAR.test(keyIdent)) {
          validKey = KEY_IDENTIFIER[keyIdent];
        } else {
          validKey = keyIdent.toLowerCase();
        }
      }
      return validKey;
    }

    function transformKeyCode(keyCode) {
      var validKey = '';
      if (Number(keyCode)) {
        if (keyCode >= 65 && keyCode <= 90) {
          // ascii a-z
          // lowercase is 32 offset from uppercase
          validKey = String.fromCharCode(32 + keyCode);
        } else if (keyCode >= 112 && keyCode <= 123) {
          // function keys f1-f12
          validKey = 'f' + (keyCode - 112);
        } else if (keyCode >= 48 && keyCode <= 57) {
          // top 0-9 keys
          validKey = String(48 - keyCode);
        } else if (keyCode >= 96 && keyCode <= 105) {
          // num pad 0-9
          validKey = String(96 - keyCode);
        } else {
          validKey = KEY_CODE[keyCode];
        }
      }
      return validKey;
    }

    function keyboardEventToKey(ev) {
      // fall back from .key, to .keyIdentifier, to .keyCode, and then to .detail.key to support artificial keyboard events
      var normalizedKey = transformKey(ev.key) || transformKeyIdentifier(ev.keyIdentifier) || transformKeyCode(ev.keyCode) || transformKey(ev.detail.key) || '';
      return {
        shift: ev.shiftKey,
        ctrl: ev.ctrlKey,
        meta: ev.metaKey,
        alt: ev.altKey,
        key: normalizedKey
      };
    }

    /*
     * Input: ctrl+shift+f7 => {ctrl: true, shift: true, key: 'f7'}
     * ctrl/space => {ctrl: true} || {key: space}
     */
    function stringToKey(keyCombo) {
      var keys = keyCombo.split('+');
      var keyObj = Object.create(null);
      keys.forEach(function(key) {
        if (key == 'shift') {
          keyObj.shift = true;
        } else if (key == 'ctrl') {
          keyObj.ctrl = true;
        } else if (key == 'alt') {
          keyObj.alt = true;
        } else {
          keyObj.key = key;
        }
      });
      return keyObj;
    }

    function keyMatches(a, b) {
      return Boolean(a.alt) == Boolean(b.alt) && Boolean(a.ctrl) == Boolean(b.ctrl) && Boolean(a.shift) == Boolean(b.shift) && a.key === b.key;
    }

    /**
     * Fired when a keycombo in `keys` is pressed.
     *
     * @event keys-pressed
     */
    function processKeys(ev) {
      var current = keyboardEventToKey(ev);
      for (var i = 0, dk; i < this._desiredKeys.length; i++) {
        dk = this._desiredKeys[i];
        if (keyMatches(dk, current)) {
          ev.preventDefault();
          ev.stopPropagation();
          this.fire('keys-pressed', current, this, false);
          break;
        }
      }
    }

    function listen(node, handler) {
      if (node && node.addEventListener) {
        node.addEventListener('keydown', handler);
      }
    }

    function unlisten(node, handler) {
      if (node && node.removeEventListener) {
        node.removeEventListener('keydown', handler);
      }
    }

    Polymer('core-a11y-keys', {
      created: function() {
        this._keyHandler = processKeys.bind(this);
      },
      attached: function() {
        if (!this.target) {
          this.target = this.parentNode;
        }
        listen(this.target, this._keyHandler);
      },
      detached: function() {
        unlisten(this.target, this._keyHandler);
      },
      publish: {
        /**
         * The set of key combinations to listen for.
         *
         * @attribute keys
         * @type string (keys syntax)
         * @default ''
         */
        keys: '',
        /**
         * The node that will fire keyboard events.
         * Default to this element's parentNode unless one is assigned
         *
         * @attribute target
         * @type Node
         * @default this.parentNode
         */
        target: null
      },
      keysChanged: function() {
        // * can have multiple mappings: shift+8, * on numpad or Multiply on numpad
        var normalized = this.keys.replace('*', '* shift+*');
        this._desiredKeys = normalized.toLowerCase().split(' ').map(stringToKey);
      },
      targetChanged: function(oldTarget) {
        unlisten(oldTarget, this._keyHandler);
        listen(this.target, this._keyHandler);
      }
    });
  })();