# Yahoo! UI Library

### dom 3.0.0

Yahoo! UI Library > dom > selector-css2.js (source view)
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    /**
     * The selector module provides helper methods allowing CSS2 Selectors to be used with DOM elements.
     * @module dom
     * @submodule selector-css2
     * @for Selector
     */

    /**
     * Provides helper methods for collecting and filtering DOM elements.
     */

    var PARENT_NODE = 'parentNode',
        TAG_NAME = 'tagName',
        ATTRIBUTES = 'attributes',
        COMBINATOR = 'combinator',
        PSEUDOS = 'pseudos',

        Selector = Y.Selector,

        SelectorCSS2 = {
            SORT_RESULTS: true,
            _children: function(node, tag) {
                var ret = node.children,
                    i,
                    children = [],
                    childNodes,
                    child;

                if (node.children && tag && node.children.tags) {
                    children = node.children.tags(tag);
                } else if ((!ret && node[TAG_NAME]) || (ret && tag)) { // only HTMLElements have children
                    childNodes = ret || node.childNodes;
                    ret = [];
                    for (i = 0; (child = childNodes[i++]);) {
                        if (child.tagName) {
                            if (!tag || tag === child.tagName) {
                                ret.push(child);
                            }
                        }
                    }
                }

                return ret || [];
            },

            _regexCache: {},

            _re: {
                attr: /(\[.*\])/g,
                pseudos: /:([\-\w]+(?:\(?:['"]?(.+)['"]?\)))*/i
            },

            /**
             * Mapping of shorthand tokens to corresponding attribute selector
             * @property shorthand
             * @type object
             */
            shorthand: {
                '\\#(-?[_a-z]+[-\\w]*)': '[id=$1]',
                '\\.(-?[_a-z]+[-\\w]*)': '[className~=$1]'
            },

            /**
             * List of operators and corresponding boolean functions.
             * These functions are passed the attribute and the current node's value of the attribute.
             * @property operators
             * @type object
             */
            operators: {
                '': function(node, attr) { return Y.DOM.getAttribute(node, attr) !== ''; }, // Just test for existence of attribute
                //'': '.+',
                //'=': '^{val}$', // equality
                '~=': '(?:^|\\s+){val}(?:\\s+|$)', // space-delimited
                '|=': '^{val}-?' // optional hyphen-delimited
            },

            pseudos: {
               'first-child': function(node) {
                    return Y.Selector._children(node[PARENT_NODE])[0] === node;
                }
            },

            _bruteQuery: function(selector, root, firstOnly) {
                var ret = [],
                    nodes = [],
                    tokens = Selector._tokenize(selector),
                    token = tokens[tokens.length - 1],
                    rootDoc = Y.DOM._getDoc(root),
                    id,
                    className,
                    tagName;

                // if we have an initial ID, set to root when in document
                if (tokens[0] && rootDoc === root &&
                        (id = tokens[0].id) &&
                        rootDoc.getElementById(id)) {
                    root = rootDoc.getElementById(id);
                }

                if (token) {
                    // prefilter nodes
                    id = token.id;
                    className = token.className;
                    tagName = token.tagName || '*';

                    // try ID first
                    if (id) {
                        if (rootDoc.getElementById(id)) { // if in document
                        nodes = [rootDoc.getElementById(id)]; // TODO: DOM.byId?
                    }
                    // try className if supported
                    } else if (className) {
                        nodes = root.getElementsByClassName(className);
                    } else if (tagName) { // default to tagName
                        nodes = root.getElementsByTagName(tagName || '*');
                    }

                    if (nodes.length) {
                        ret = Selector._filterNodes(nodes, tokens, firstOnly);
                    }
                }

                return ret;
            },

            _filterNodes: function(nodes, tokens, firstOnly) {
                var i = 0,
                    j,
                    len = tokens.length,
                    n = len - 1,
                    result = [],
                    node = nodes[0],
                    tmpNode = node,
                    getters = Y.Selector.getters,
                    operator,
                    combinator,
                    token,
                    path,
                    pass,
                    //FUNCTION = 'function',
                    value,
                    tests,
                    test;

                //do {
                for (i = 0; (tmpNode = node = nodes[i++]);) {
                    n = len - 1;
                    path = null;

                    testLoop:
                    while (tmpNode && tmpNode.tagName) {
                        token = tokens[n];
                        tests = token.tests;
                        j = tests.length;
                        if (j && !pass) {
                            while ((test = tests[--j])) {
                                operator = test[1];
                                if (getters[test[0]]) {
                                    value = getters[test[0]](tmpNode, test[0]);
                                } else {
                                    value = tmpNode[test[0]];
                                    // use getAttribute for non-standard attributes
                                    if (value === undefined && tmpNode.getAttribute) {
                                        value = tmpNode.getAttribute(test[0]);
                                    }
                                }

                                if ((operator === '=' && value !== test[2]) ||  // fast path for equality
                                    (operator.test && !operator.test(value)) ||  // regex test
                                    (operator.call && !operator(tmpNode, test[0]))) { // function test

                                    // skip non element nodes or non-matching tags
                                    if ((tmpNode = tmpNode[path])) {
                                        while (tmpNode &&
                                            (!tmpNode.tagName ||
                                                (token.tagName && token.tagName !== tmpNode.tagName))
                                        ) {
                                            tmpNode = tmpNode[path];
                                        }
                                    }
                                    continue testLoop;
                                }
                            }
                        }

                        n--; // move to next token
                        // now that we've passed the test, move up the tree by combinator
                        if (!pass && (combinator = token.combinator)) {
                            path = combinator.axis;
                            tmpNode = tmpNode[path];

                            // skip non element nodes
                            while (tmpNode && !tmpNode.tagName) {
                                tmpNode = tmpNode[path];
                            }

                            if (combinator.direct) { // one pass only
                                path = null;
                            }

                        } else { // success if we made it this far
                            result.push(node);
                            if (firstOnly) {
                                return result;
                            }
                            break;
                        }
                    }
                }// while (tmpNode = node = nodes[++i]);
                node = tmpNode = null;
                return result;
            },

            _getRegExp: function(str, flags) {
                var regexCache = Selector._regexCache;
                flags = flags || '';
                if (!regexCache[str + flags]) {
                    regexCache[str + flags] = new RegExp(str, flags);
                }
                return regexCache[str + flags];
            },

            combinators: {
                ' ': {
                    axis: 'parentNode'
                },

                '>': {
                    axis: 'parentNode',
                    direct: true
                },

                '+': {
                    axis: 'previousSibling',
                    direct: true
                }
            },

            _parsers: [
                {
                    name: ATTRIBUTES,
                    re: /^\[([a-z]+\w*)+([~\|\^\$\*!=]=?)?['"]?([^\]]*?)['"]?\]/i,
                    fn: function(match, token) {
                        var operator = match[2] || '',
                            operators = Y.Selector.operators,
                            test;

                        // add prefiltering for ID and CLASS
                        if ((match[1] === 'id' && operator === '=') ||
                                (match[1] === 'className' &&
                                document.getElementsByClassName &&
                                (operator === '~=' || operator === '='))) {
                            token.prefilter = match[1];
                            token[match[1]] = match[3];
                        }

                        // add tests
                        if (operator in operators) {
                            test = operators[operator];
                            if (typeof test === 'string') {
                                test = Y.Selector._getRegExp(test.replace('{val}', match[3]));
                            }
                            match[2] = test;
                        }
                        if (!token.last || token.prefilter !== match[1]) {
                            return match.slice(1);
                        }
                    }

                },
                {
                    name: TAG_NAME,
                    re: /^((?:-?[_a-z]+[\w-]*)|\*)/i,
                    fn: function(match, token) {
                        var tag = match[1].toUpperCase();
                        token.tagName = tag;

                        if (tag !== '*' && (!token.last || token.prefilter)) {
                            return [TAG_NAME, '=', tag];
                        }
                        if (!token.prefilter) {
                            token.prefilter = 'tagName';
                        }
                    }
                },
                {
                    name: COMBINATOR,
                    re: /^\s*([>+~]|\s)\s*/,
                    fn: function(match, token) {
                    }
                },
                {
                    name: PSEUDOS,
                    re: /^:([\-\w]+)(?:\(['"]?(.+)['"]?\))*/i,
                    fn: function(match, token) {
                        var test = Selector[PSEUDOS][match[1]];
                        if (test) { // reorder match array
                            return [match[2], test];
                        } else { // selector token not supported (possibly missing CSS3 module)
                            return false;
                        }
                    }
                }
                ],

            _getToken: function(token) {
                return {
                    tagName: null,
                    id: null,
                    className: null,
                    attributes: {},
                    combinator: null,
                    tests: []
                };
            },

            /**
                Break selector into token units per simple selector.
                Combinator is attached to the previous token.
             */
            _tokenize: function(selector) {
                selector = selector || '';
                selector = Selector._replaceShorthand(Y.Lang.trim(selector));
                var token = Selector._getToken(),     // one token per simple selector (left selector holds combinator)
                    query = selector, // original query for debug report
                    tokens = [],    // array of tokens
                    found = false,  // whether or not any matches were found this pass
                    match,         // the regex match
                    test,
                    i, parser;

                /*
                    Search for selector patterns, store, and strip them from the selector string
                    until no patterns match (invalid selector) or we run out of chars.

                    Multiple attributes and pseudos are allowed, in any order.
                    for example:
                        'form:first-child[type=button]:not(button)[lang|=en]'
                */
                outer:
                do {
                    found = false; // reset after full pass
                    for (i = 0; (parser = Selector._parsers[i++]);) {
                        if ( (match = parser.re.exec(selector)) ) { // note assignment
                            if (parser !== COMBINATOR ) {
                                token.selector = selector;
                            }
                            selector = selector.replace(match[0], ''); // strip current match from selector
                            if (!selector.length) {
                                token.last = true;
                            }

                            if (Selector._attrFilters[match[1]]) { // convert class to className, etc.
                                match[1] = Selector._attrFilters[match[1]];
                            }

                            test = parser.fn(match, token);
                            if (test === false) { // selector not supported
                                found = false;
                                break outer;
                            } else if (test) {
                                token.tests.push(test);
                            }

                            if (!selector.length || parser.name === COMBINATOR) {
                                tokens.push(token);
                                token = Selector._getToken(token);
                                if (parser.name === COMBINATOR) {
                                    token.combinator = Y.Selector.combinators[match[1]];
                                }
                            }
                            found = true;
                        }
                    }
                } while (found && selector.length);

                if (!found || selector.length) { // not fully parsed
                    Y.log('query: ' + query + ' contains unsupported token in: ' + selector, 'warn', 'Selector');
                    tokens = [];
                }
                return tokens;
            },

            _replaceShorthand: function(selector) {
                var shorthand = Selector.shorthand,
                    attrs = selector.match(Selector._re.attr), // pull attributes to avoid false pos on "." and "#"
                    pseudos = selector.match(Selector._re.pseudos), // pull attributes to avoid false pos on "." and "#"
                    re, i, len;

                if (pseudos) {
                    selector = selector.replace(Selector._re.pseudos, '!!REPLACED_PSEUDO!!');
                }

                if (attrs) {
                    selector = selector.replace(Selector._re.attr, '!!REPLACED_ATTRIBUTE!!');
                }

                for (re in shorthand) {
                    if (shorthand.hasOwnProperty(re)) {
                        selector = selector.replace(Selector._getRegExp(re, 'gi'), shorthand[re]);
                    }
                }

                if (attrs) {
                    for (i = 0, len = attrs.length; i < len; ++i) {
                        selector = selector.replace('!!REPLACED_ATTRIBUTE!!', attrs[i]);
                    }
                }
                if (pseudos) {
                    for (i = 0, len = pseudos.length; i < len; ++i) {
                        selector = selector.replace('!!REPLACED_PSEUDO!!', pseudos[i]);
                    }
                }
                return selector;
            },

            _attrFilters: {
                'class': 'className',
                'for': 'htmlFor'
            },

            getters: {
                href: function(node, attr) {
                    return Y.DOM.getAttribute(node, attr);
                }
            }
        };

    Y.mix(Y.Selector, SelectorCSS2, true);
    Y.Selector.getters.src = Y.Selector.getters.rel = Y.Selector.getters.href;

    // IE wants class with native queries
    if (Y.Selector.useNative && document.querySelector) {
        Y.Selector.shorthand['\\.(-?[_a-z]+[-\\w]*)'] = '[class~=$1]';
    }

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