source: Dev/trunk/src/client/dojo/NodeList-data.js

define([
        "./_base/kernel", "./query", "./_base/lang", "./_base/array", "./dom-attr"
], function(dojo, query, lang, array, attr){

        // module:
        //              dojo/NodeList-data

        /*=====
        return function(){
                // summary:
                //              Adds data() and removeData() methods to NodeList, and returns NodeList constructor.
        };
        =====*/

        var NodeList = query.NodeList;

        var dataCache = {}, x = 0, dataattr = "data-dojo-dataid",
                dopid = function(node){
                        // summary:
                        //              Return a uniqueish ID for the passed node reference
                        var pid = attr.get(node, dataattr);
                        if(!pid){
                                pid = "pid" + (x++);
                                attr.set(node, dataattr, pid);
                        }
                        return pid;
                }
        ;

        //>>excludeStart("debugging", true);
        // An alias to the private dataCache for NodeList-data. NEVER USE THIS!
        // This private is only exposed for the benefit of unit testing, and is
        // removed during the build process.
        NodeList._nodeDataCache = dojo._nodeDataCache = dataCache;
        //>>excludeEnd("debugging");

        var dodata = dojo._nodeData = function(node, key, value){
                // summary:
                //              Private helper for dojo/NodeList.data for single node data access. Refer to NodeList.data
                //              documentation for more information.
                //
                // node: String|DomNode
                //              The node to associate data with
                //
                // key: Object|String?
                //              If an object, act as a setter and iterate over said object setting data items as defined.
                //              If a string, and `value` present, set the data for defined `key` to `value`
                //              If a string, and `value` absent, act as a getter, returning the data associated with said `key`
                //
                // value: Anything?
                //              The value to set for said `key`, provided `key` is a string (and not an object)
                //
                var pid = dopid(node), r;
                if(!dataCache[pid]){ dataCache[pid] = {}; }

                // API discrepency: calling with only a node returns the whole object. $.data throws
                if(arguments.length == 1){ r = dataCache[pid]; }
                if(typeof key == "string"){
                        // either getter or setter, based on `value` presence
                        if(arguments.length > 2){
                                dataCache[pid][key] = value;
                        }else{
                                r = dataCache[pid][key];
                        }
                }else{
                        // must be a setter, mix `value` into data hash
                        // API discrepency: using object as setter works here
                        r = lang.mixin(dataCache[pid], key);
                }

                return r; // Object|Anything|Nothing
        };

        var removeData = dojo._removeNodeData = function(node, key){
                // summary:
                //              Remove some data from this node
                // node: String|DomNode
                //              The node reference to remove data from
                // key: String?
                //              If omitted, remove all data in this dataset.
                //              If passed, remove only the passed `key` in the associated dataset
                var pid = dopid(node);
                if(dataCache[pid]){
                        if(key){
                                delete dataCache[pid][key];
                        }else{
                                delete dataCache[pid];
                        }
                }
        };

        NodeList._gcNodeData = dojo._gcNodeData = function(){
                // summary:
                //              super expensive: GC all data in the data for nodes that no longer exist in the dom.
                // description:
                //              super expensive: GC all data in the data for nodes that no longer exist in the dom.
                //              MUCH safer to do this yourself, manually, on a per-node basis (via `NodeList.removeData()`)
                //              provided as a stop-gap for exceptionally large/complex applications with constantly changing
                //              content regions (eg: a dijit/layout/ContentPane with replacing data)
                //              There is NO automatic GC going on. If you dojo.destroy() a node, you should _removeNodeData
                //              prior to destruction.
                var livePids = query("[" + dataattr + "]").map(dopid);
                for(var i in dataCache){
                        if(array.indexOf(livePids, i) < 0){ delete dataCache[i]; }
                }
        };

        // make nodeData and removeNodeData public on dojo/NodeList:
        lang.extend(NodeList, {
                data: NodeList._adaptWithCondition(dodata, function(a){
                        return a.length === 0 || a.length == 1 && (typeof a[0] == "string");
                }),
                removeData: NodeList._adaptAsForEach(removeData)
        });

        /*=====
         lang.extend(NodeList, {
                 data: function(key, value){
                        // summary:
                        //              stash or get some arbitrary data on/from these nodes.
                        //
                        // description:
                        //              Stash or get some arbitrary data on/from these nodes. This private _data function is
                        //              exposed publicly on `dojo/NodeList`, eg: as the result of a `dojo/query` call.
                        //              DIFFERS from jQuery.data in that when used as a getter, the entire list is ALWAYS
                        //              returned. EVEN WHEN THE LIST IS length == 1.
                        //
                        //              A single-node version of this function is provided as `dojo._nodeData`, which follows
                        //              the same signature, though expects a String ID or DomNode reference in the first
                        //              position, before key/value arguments.
                        //
                        // node: String|DomNode
                        //              The node to associate data with
                        //
                        // key: Object|String?
                        //              If an object, act as a setter and iterate over said object setting data items as defined.
                        //              If a string, and `value` present, set the data for defined `key` to `value`
                        //              If a string, and `value` absent, act as a getter, returning the data associated with said `key`
                        //
                        // value: Anything?
                        //              The value to set for said `key`, provided `key` is a string (and not an object)
                        //
                        // example:
                        //              Set a key `bar` to some data, then retrieve it.
                        //      |       require(["dojo/query", "dojo/NodeList-data"], function(query){
                        //      |               query(".foo").data("bar", "touched");
                        //      |               var touched = query(".foo").data("bar");
                        //      |               if(touched[0] == "touched"){ alert('win'); }
                        //      |       });
                        //
                        // example:
                        //              Get all the data items for a given node.
                        //      |       require(["dojo/query", "dojo/NodeList-data"], function(query){
                        //      |               var list = query(".foo").data();
                        //      |               var first = list[0];
                        //      |       });
                        //
                        // example:
                        //              Set the data to a complex hash. Overwrites existing keys with new value
                        //      |       require(["dojo/query", "dojo/NodeList-data"], function(query){
                        //      |               query(".foo").data({ bar:"baz", foo:"bar" });
                        //              Then get some random key:
                        //      |               query(".foo").data("foo"); // returns [`bar`]
                        //      |       });
                        //
                        // returns: Object|Anything|Nothing
                        //              When used as a setter via `dojo/NodeList`, a NodeList instance is returned
                        //              for further chaining. When used as a getter via `dojo/NodeList` an ARRAY
                        //              of items is returned. The items in the array correspond to the elements
                        //              in the original list. This is true even when the list length is 1, eg:
                        //              when looking up a node by ID (#foo)
                 },

                 removeData: function(key){
                        // summary:
                        //              Remove the data associated with these nodes.
                        // key: String?
                        //              If omitted, clean all data for this node.
                        //              If passed, remove the data item found at `key`
                 }
         });
         =====*/

// TODO: this is the basic implementation of adaptWithConditionAndWhenMappedConsiderLength, for lack of a better API name
// it conflicts with the the `dojo/NodeList` way: always always return an arrayLike thinger. Consider for 2.0:
//
//      NodeList.prototype.data = function(key, value){
//              var a = arguments, r;
//              if(a.length === 0 || a.length == 1 && (typeof a[0] == "string")){
//                      r = this.map(function(node){
//                              return d._data(node, key);
//                      });
//                      if(r.length == 1){ r = r[0]; } // the offending line, and the diff on adaptWithCondition
//              }else{
//                      r = this.forEach(function(node){
//                              d._data(node, key, value);
//                      });
//              }
//              return r; // NodeList|Array|SingleItem
//      };

        return NodeList;

});