define(["../core","../var/rnotwhite","./accepts"
], function( jQuery, rnotwhite ) {function Data() {// Support: Android<4,// Old WebKit does not have Object.preventExtensions/freeze method,// return new empty object instead with no [[set]] accessorObject.defineProperty( this.cache = {}, 0, {get: function() {return {};}});//  jQuery.expando = "jQuery" + ( version + Math.random() ).replace( /\D/g, "" ) expando是一个jQuery的唯一标示// 格式是：'jQuery\\d*'  也就是'jQuery'+ 多个数字。这里为啥要搞得这么麻烦呢？// 应因为我们可能会创建多个Data对象，为了保证每个Data对象的expando属性的值不相等，所以这么搞this.expando = jQuery.expando + Math.random();
}Data.uid = 1;  // Data函数的属性，'静态属性'
Data.accepts = jQuery.acceptData;Data.prototype = {key: function( owner ) {// We can accept data for non-element nodes in modern browsers,// but we should not, see #8335.// Always return the key for a frozen object.// 若owner在该缓存池中存在对应的缓存对象，则返回混存对象的key(是一个数字)，// 若owner在该缓存池中不存在对应的缓存对象，则在缓存池中为其创建一个缓存对象，并返回该缓存对象的keyif ( !Data.accepts( owner ) ) {return 0;}var descriptor = {},// Check if the owner object already has a cache key// 检查owner对象在该缓存池中是否存在缓存unlock = owner[ this.expando ];  // 是一个数字，用来作为缓存池中缓存对象的key// If not, create one// 如果没有，则创建一个if ( !unlock ) {unlock = Data.uid++;// Secure it in a non-enumerable, non-writable property// 给owner附加一个属性  owner[this.expando] = unlock ，并且该属性不能被枚举，try {descriptor[ this.expando ] = { value: unlock };Object.defineProperties( owner, descriptor );// Support: Android<4// Fallback to a less secure definition} catch ( e ) {descriptor[ this.expando ] = unlock;jQuery.extend( owner, descriptor );}}// Ensure the cache object// 确保owner对应的缓存对象已存在if ( !this.cache[ unlock ] ) {this.cache[ unlock ] = {};}//  返回unlockreturn unlock;},set: function( owner, data, value ) {// 设置owner对应的缓存对象var prop,// There may be an unlock assigned to this node,// if there is no entry for this "owner", create one inline// and set the unlock as though an owner entry had always existedunlock = this.key( owner ),  // 获取owner的对应的缓存对象在缓存池中的key(这里的key，是键值对中的键的意思)cache = this.cache[ unlock ];  // 获取owner所对应的缓存对象// Handle: [ owner, key, value ] args// 根据传入参数的个数以及类型实现重载if ( typeof data === "string" ) {cache[ data ] = value;// Handle: [ owner, { properties } ] args} else {// Fresh assignments by object are shallow copiedif ( jQuery.isEmptyObject( cache ) ) {jQuery.extend( this.cache[ unlock ], data );// Otherwise, copy the properties one-by-one to the cache object} else {for ( prop in data ) {cache[ prop ] = data[ prop ];}}}// 返回缓存对象return cache;},get: function( owner, key ) {// 获取owner对象的名为key的属性值// owner:是一个对象(可以是jQuery对象也可以是DOM对象)   key: 属性名// Either a valid cache is found, or will be created.// New caches will be created and the unlock returned,// allowing direct access to the newly created// empty data object. A valid owner object must be provided.var cache = this.cache[ this.key( owner ) ]; //  owner的缓存对象return key === undefined ? cache : cache[ key ];  // 没指定key的话就返回整个缓存对象，若指定了key则返回在该缓存对象的key属性的值
    },access: function( owner, key, value ) {var stored;// In cases where either://
        //   1. No key was specified   没有指定key//   2. A string key was specified, but no value provided  指定了字符串格式的key，但没有指定value//
        // Take the "read" path and allow the get method to determine// which value to return, respectively either://
        //   1. The entire cache object  整个缓存对象//   2. The data stored at the key  缓存对象中某个键的值//
        if ( key === undefined || // 没有指定key或者指定了字符串格式的key，但没有指定value((key && typeof key === "string") && value === undefined) ) {// 没有指定key：获取整个缓存对象// 指定了字符串格式的key，但没有指定value： 获取缓存对象中key的值stored = this.get( owner, key );return stored !== undefined ?stored : this.get( owner, jQuery.camelCase(key) );}// [*]When the key is not a string, or both a key and value// are specified, set or extend (existing objects) with either:// 当key不是一个字符串，或者key和value都指定了，就会根据情况进行设置或者扩展//
        //   1. An object of properties//   2. A key and value//
        this.set( owner, key, value );// Since the "set" path can have two possible entry points// return the expected data based on which path was taken[*]return value !== undefined ? value : key;},remove: function( owner, key ) {// 清空owner对应的缓存对象，或者移除缓存对象中的某个键值对var i, name, camel,unlock = this.key( owner ),cache = this.cache[ unlock ];// 如果没有指定key，则清空缓存对象if ( key === undefined ) {this.cache[ unlock ] = {};} else {// Support array or space separated string of keysif ( jQuery.isArray( key ) ) {// If "name" is an array of keys...// When data is initially created, via ("key", "val") signature,// keys will be converted to camelCase.// Since there is no way to tell _how_ a key was added, remove// both plain key and camelCase key. #12786// This will only penalize the array argument path.name = key.concat( key.map( jQuery.camelCase ) );} else {camel = jQuery.camelCase( key );// Try the string as a key before any manipulationif ( key in cache ) {name = [ key, camel ];} else {// If a key with the spaces exists, use it.// Otherwise, create an array by matching non-whitespacename = camel;name = name in cache ?[ name ] : ( name.match( rnotwhite ) || [] );}}i = name.length;while ( i-- ) {delete cache[ name[ i ] ];}}},hasData: function( owner ) {// 检查owner在该缓存池中是否存在缓存对象return !jQuery.isEmptyObject(this.cache[ owner[ this.expando ] ] || {});},discard: function( owner ) {if ( owner[ this.expando ] ) {delete this.cache[ owner[ this.expando ] ];}}
};return Data;
});