source: Dev/trunk/src/client/dojo/selector/lite.js

define(["../has", "../_base/kernel"], function(has, dojo){
"use strict";

var testDiv = document.createElement("div");
var matchesSelector = testDiv.matchesSelector || testDiv.webkitMatchesSelector || testDiv.mozMatchesSelector || testDiv.msMatchesSelector || testDiv.oMatchesSelector; // IE9, WebKit, Firefox have this, but not Opera yet
var querySelectorAll = testDiv.querySelectorAll;
var unionSplit = /([^\s,](?:"(?:\\.|[^"])+"|'(?:\\.|[^'])+'|[^,])*)/g;
has.add("dom-matches-selector", !!matchesSelector);
has.add("dom-qsa", !!querySelectorAll); 

// this is a simple query engine. It has handles basic selectors, and for simple
// common selectors is extremely fast
var liteEngine = function(selector, root){
        // summary:
        //              A small lightweight query selector engine that implements CSS2.1 selectors
        //              minus pseudo-classes and the sibling combinator, plus CSS3 attribute selectors

        if(combine && selector.indexOf(',') > -1){
                return combine(selector, root);
        }
        // use the root's ownerDocument if provided, otherwise try to use dojo.doc. Note 
        // that we don't use dojo/_base/window's doc to reduce dependencies, and 
        // fallback to plain document if dojo.doc hasn't been defined (by dojo/_base/window).
        // presumably we will have a better way to do this in 2.0 
        var doc = root ? root.ownerDocument || root : dojo.doc || document, 
                match = (querySelectorAll ? 
                        /^([\w]*)#([\w\-]+$)|^(\.)([\w\-\*]+$)|^(\w+$)/ : // this one only matches on simple queries where we can beat qSA with specific methods
                        /^([\w]*)#([\w\-]+)(?:\s+(.*))?$|(?:^|(>|.+\s+))([\w\-\*]+)(\S*$)/) // this one matches parts of the query that we can use to speed up manual filtering
                        .exec(selector);
        root = root || doc;
        if(match){
                // fast path regardless of whether or not querySelectorAll exists
                if(match[2]){
                        // an #id
                        // use dojo.byId if available as it fixes the id retrieval in IE, note that we can't use the dojo namespace in 2.0, but if there is a conditional module use, we will use that
                        var found = dojo.byId ? dojo.byId(match[2], doc) : doc.getElementById(match[2]);
                        if(!found || (match[1] && match[1] != found.tagName.toLowerCase())){
                                // if there is a tag qualifer and it doesn't match, no matches
                                return [];
                        }
                        if(root != doc){
                                // there is a root element, make sure we are a child of it
                                var parent = found;
                                while(parent != root){
                                        parent = parent.parentNode;
                                        if(!parent){
                                                return [];
                                        }
                                }
                        }
                        return match[3] ?
                                        liteEngine(match[3], found) 
                                        : [found];
                }
                if(match[3] && root.getElementsByClassName){
                        // a .class
                        return root.getElementsByClassName(match[4]);
                }
                var found;
                if(match[5]){
                        // a tag
                        found = root.getElementsByTagName(match[5]);
                        if(match[4] || match[6]){
                                selector = (match[4] || "") + match[6];
                        }else{
                                // that was the entirety of the query, return results
                                return found;
                        }
                }
        }
        if(querySelectorAll){
                // qSA works strangely on Element-rooted queries
                // We can work around this by specifying an extra ID on the root
                // and working up from there (Thanks to Andrew Dupont for the technique)
                // IE 8 doesn't work on object elements
                if (root.nodeType === 1 && root.nodeName.toLowerCase() !== "object"){                           
                        return useRoot(root, selector, root.querySelectorAll);
                }else{
                        // we can use the native qSA
                        return root.querySelectorAll(selector);
                }
        }else if(!found){
                // search all children and then filter
                found = root.getElementsByTagName("*");
        }
        // now we filter the nodes that were found using the matchesSelector
        var results = [];
        for(var i = 0, l = found.length; i < l; i++){
                var node = found[i];
                if(node.nodeType == 1 && jsMatchesSelector(node, selector, root)){
                        // keep the nodes that match the selector
                        results.push(node);
                }
        }
        return results;
};
var useRoot = function(context, query, method){
        // this function creates a temporary id so we can do rooted qSA queries, this is taken from sizzle
        var oldContext = context,
                old = context.getAttribute("id"),
                nid = old || "__dojo__",
                hasParent = context.parentNode,
                relativeHierarchySelector = /^\s*[+~]/.test(query);

        if(relativeHierarchySelector && !hasParent){
                return [];
        }
        if(!old){
                context.setAttribute("id", nid);
        }else{
                nid = nid.replace(/'/g, "\\$&");
        }
        if(relativeHierarchySelector && hasParent){
                context = context.parentNode;
        }
        var selectors = query.match(unionSplit);
        for(var i = 0; i < selectors.length; i++){
                selectors[i] = "[id='" + nid + "'] " + selectors[i];
        }
        query = selectors.join(",");

        try{
                return method.call(context, query);
        }finally{
                if(!old){
                        oldContext.removeAttribute("id");
                }
        }
};

if(!has("dom-matches-selector")){
        var jsMatchesSelector = (function(){
                // a JS implementation of CSS selector matching, first we start with the various handlers
                var caseFix = testDiv.tagName == "div" ? "toLowerCase" : "toUpperCase";
                var selectorTypes = {
                        "": function(tagName){
                                tagName = tagName[caseFix]();
                                return function(node){
                                        return node.tagName == tagName;
                                };
                        },
                        ".": function(className){
                                var classNameSpaced = ' ' + className + ' ';
                                return function(node){
                                        return node.className.indexOf(className) > -1 && (' ' + node.className + ' ').indexOf(classNameSpaced) > -1;
                                };
                        },
                        "#": function(id){
                                return function(node){
                                        return node.id == id;
                                };
                        }
                };
                var attrComparators = {
                        "^=": function(attrValue, value){
                                return attrValue.indexOf(value) == 0;
                        },
                        "*=": function(attrValue, value){
                                return attrValue.indexOf(value) > -1;
                        },
                        "$=": function(attrValue, value){
                                return attrValue.substring(attrValue.length - value.length, attrValue.length) == value;
                        },
                        "~=": function(attrValue, value){
                                return (' ' + attrValue + ' ').indexOf(' ' + value + ' ') > -1;
                        },
                        "|=": function(attrValue, value){
                                return (attrValue + '-').indexOf(value + '-') == 0;
                        },
                        "=": function(attrValue, value){
                                return attrValue == value;
                        },
                        "": function(attrValue, value){
                                return true;
                        }
                };
                function attr(name, value, type){
                        var firstChar = value.charAt(0);
                        if(firstChar == '"' || firstChar == "'"){
                                // it is quoted, remove the quotes
                                value = value.slice(1, -1);
                        }
                        value = value.replace(/\\/g,'');
                        var comparator = attrComparators[type || ""];
                        return function(node){
                                var attrValue = node.getAttribute(name);
                                return attrValue && comparator(attrValue, value);
                        };
                }
                function ancestor(matcher){
                        return function(node, root){
                                while((node = node.parentNode) != root){
                                        if(matcher(node, root)){
                                                return true;
                                        }
                                }
                        };
                }
                function parent(matcher){
                        return function(node, root){
                                node = node.parentNode;
                                return matcher ? 
                                        node != root && matcher(node, root)
                                        : node == root;
                        };
                }
                var cache = {};
                function and(matcher, next){
                        return matcher ?
                                function(node, root){
                                        return next(node) && matcher(node, root);
                                }
                                : next;
                }
                return function(node, selector, root){
                        // this returns true or false based on if the node matches the selector (optionally within the given root)
                        var matcher = cache[selector]; // check to see if we have created a matcher function for the given selector
                        if(!matcher){
                                // create a matcher function for the given selector
                                // parse the selectors
                                if(selector.replace(/(?:\s*([> ])\s*)|(#|\.)?((?:\\.|[\w-])+)|\[\s*([\w-]+)\s*(.?=)?\s*("(?:\\.|[^"])+"|'(?:\\.|[^'])+'|(?:\\.|[^\]])*)\s*\]/g, function(t, combinator, type, value, attrName, attrType, attrValue){
                                        if(value){
                                                matcher = and(matcher, selectorTypes[type || ""](value.replace(/\\/g, '')));
                                        }
                                        else if(combinator){
                                                matcher = (combinator == " " ? ancestor : parent)(matcher);
                                        }
                                        else if(attrName){
                                                matcher = and(matcher, attr(attrName, attrValue, attrType));
                                        }
                                        return "";
                                })){
                                        throw new Error("Syntax error in query");
                                }
                                if(!matcher){
                                        return true;
                                }
                                cache[selector] = matcher;
                        }
                        // now run the matcher function on the node
                        return matcher(node, root);
                };
        })();
}
if(!has("dom-qsa")){
        var combine = function(selector, root){
                // combined queries
                var selectors = selector.match(unionSplit);
                var indexed = [];
                // add all results and keep unique ones, this only runs in IE, so we take advantage 
                // of known IE features, particularly sourceIndex which is unique and allows us to 
                // order the results 
                for(var i = 0; i < selectors.length; i++){
                        selector = new String(selectors[i].replace(/\s*$/,''));
                        selector.indexOf = escape; // keep it from recursively entering combine
                        var results = liteEngine(selector, root);
                        for(var j = 0, l = results.length; j < l; j++){
                                var node = results[j];
                                indexed[node.sourceIndex] = node;
                        }
                }
                // now convert from a sparse array to a dense array
                var totalResults = [];
                for(i in indexed){
                        totalResults.push(indexed[i]);
                }
                return totalResults;
        };
}

liteEngine.match = matchesSelector ? function(node, selector, root){
        if(root && root.nodeType != 9){
                // doesn't support three args, use rooted id trick
                return useRoot(root, selector, function(query){
                        return matchesSelector.call(node, query);
                });
        }
        // we have a native matchesSelector, use that
        return matchesSelector.call(node, selector);
} : jsMatchesSelector; // otherwise use the JS matches impl

return liteEngine;
});