1 /*

     2 YUI 3.10.3 (build 2fb5187)

     3 Copyright 2013 Yahoo! Inc. All rights reserved.

     4 Licensed under the BSD License.

     5 http://yuilibrary.com/license/

     6 */

     7 

     8 YUI.add('cache-base', function (Y, NAME) {

     9 

    10 /**

    11  * The Cache utility provides a common configurable interface for components to

    12  * cache and retrieve data from a local JavaScript struct.

    13  *

    14  * @module cache

    15  * @main

    16  */

    17 

    18 /**

    19  * Provides the base class for the YUI Cache utility.

    20  *

    21  * @submodule cache-base

    22  */

    23 var LANG = Y.Lang,

    24     isDate = Y.Lang.isDate,

    25 

    26 /**

    27  * Base class for the YUI Cache utility.

    28  * @class Cache

    29  * @extends Base

    30  * @constructor

    31  */

    32 Cache = function() {

    33     Cache.superclass.constructor.apply(this, arguments);

    34 };

    35 

    36     /////////////////////////////////////////////////////////////////////////////

    37     //

    38     // Cache static properties

    39     //

    40     /////////////////////////////////////////////////////////////////////////////

    41 Y.mix(Cache, {

    42     /**

    43      * Class name.

    44      *

    45      * @property NAME

    46      * @type String

    47      * @static

    48      * @final

    49      * @value "cache"

    50      */

    51     NAME: "cache",

    52 

    53 

    54     ATTRS: {

    55         /////////////////////////////////////////////////////////////////////////////

    56         //

    57         // Cache Attributes

    58         //

    59         /////////////////////////////////////////////////////////////////////////////

    60 

    61         /**

    62         * @attribute max

    63         * @description Maximum number of entries the Cache can hold.

    64         * Set to 0 to turn off caching.

    65         * @type Number

    66         * @default 0

    67         */

    68         max: {

    69             value: 0,

    70             setter: "_setMax"

    71         },

    72 

    73         /**

    74         * @attribute size

    75         * @description Number of entries currently cached.

    76         * @type Number

    77         */

    78         size: {

    79             readOnly: true,

    80             getter: "_getSize"

    81         },

    82 

    83         /**

    84         * @attribute uniqueKeys

    85         * @description Validate uniqueness of stored keys. Default is false and

    86         * is more performant.

    87         * @type Boolean

    88         */

    89         uniqueKeys: {

    90             value: false

    91         },

    92 

    93         /**

    94         * @attribute expires

    95         * @description Absolute Date when data expires or

    96         * relative number of milliseconds. Zero disables expiration.

    97         * @type Date | Number

    98         * @default 0

    99         */

   100         expires: {

   101             value: 0,

   102             validator: function(v) {

   103                 return Y.Lang.isDate(v) || (Y.Lang.isNumber(v) && v >= 0);

   104             }

   105         },

   106 

   107         /**

   108          * @attribute entries

   109          * @description Cached entries.

   110          * @type Array

   111          */

   112         entries: {

   113             readOnly: true,

   114             getter: "_getEntries"

   115         }

   116     }

   117 });

   118 

   119 Y.extend(Cache, Y.Base, {

   120     /////////////////////////////////////////////////////////////////////////////

   121     //

   122     // Cache private properties

   123     //

   124     /////////////////////////////////////////////////////////////////////////////

   125 

   126     /**

   127      * Array of request/response objects indexed chronologically.

   128      *

   129      * @property _entries

   130      * @type Object[]

   131      * @private

   132      */

   133     _entries: null,

   134 

   135     /////////////////////////////////////////////////////////////////////////////

   136     //

   137     // Cache private methods

   138     //

   139     /////////////////////////////////////////////////////////////////////////////

   140 

   141     /**

   142     * @method initializer

   143     * @description Internal init() handler.

   144     * @param config {Object} Config object.

   145     * @private

   146     */

   147     initializer: function(config) {

   148 

   149         /**

   150         * @event add

   151         * @description Fired when an entry is added.

   152         * @param e {Event.Facade} Event Facade with the following properties:

   153          * <dl>

   154          * <dt>entry (Object)</dt> <dd>The cached entry.</dd>

   155          * </dl>

   156         * @preventable _defAddFn

   157         */

   158         this.publish("add", {defaultFn: this._defAddFn});

   159 

   160         /**

   161         * @event flush

   162         * @description Fired when the cache is flushed.

   163         * @param e {Event.Facade} Event Facade object.

   164         * @preventable _defFlushFn

   165         */

   166         this.publish("flush", {defaultFn: this._defFlushFn});

   167 

   168         /**

   169         * @event request

   170         * @description Fired when an entry is requested from the cache.

   171         * @param e {Event.Facade} Event Facade with the following properties:

   172         * <dl>

   173         * <dt>request (Object)</dt> <dd>The request object.</dd>

   174         * </dl>

   175         */

   176 

   177         /**

   178         * @event retrieve

   179         * @description Fired when an entry is retrieved from the cache.

   180         * @param e {Event.Facade} Event Facade with the following properties:

   181         * <dl>

   182         * <dt>entry (Object)</dt> <dd>The retrieved entry.</dd>

   183         * </dl>

   184         */

   185 

   186         // Initialize internal values

   187         this._entries = [];

   188     },

   189 

   190     /**

   191     * @method destructor

   192     * @description Internal destroy() handler.

   193     * @private

   194     */

   195     destructor: function() {

   196         this._entries = [];

   197     },

   198 

   199     /////////////////////////////////////////////////////////////////////////////

   200     //

   201     // Cache protected methods

   202     //

   203     /////////////////////////////////////////////////////////////////////////////

   204 

   205     /**

   206      * Sets max.

   207      *

   208      * @method _setMax

   209      * @protected

   210      */

   211     _setMax: function(value) {

   212         // If the cache is full, make room by removing stalest element (index=0)

   213         var entries = this._entries;

   214         if(value > 0) {

   215             if(entries) {

   216                 while(entries.length > value) {

   217                     entries.shift();

   218                 }

   219             }

   220         }

   221         else {

   222             value = 0;

   223             this._entries = [];

   224         }

   225         return value;

   226     },

   227 

   228     /**

   229      * Gets size.

   230      *

   231      * @method _getSize

   232      * @protected

   233      */

   234     _getSize: function() {

   235         return this._entries.length;

   236     },

   237 

   238     /**

   239      * Gets all entries.

   240      *

   241      * @method _getEntries

   242      * @protected

   243      */

   244     _getEntries: function() {

   245         return this._entries;

   246     },

   247 

   248 

   249     /**

   250      * Adds entry to cache.

   251      *

   252      * @method _defAddFn

   253      * @param e {Event.Facade} Event Facade with the following properties:

   254      * <dl>

   255      * <dt>entry (Object)</dt> <dd>The cached entry.</dd>

   256      * </dl>

   257      * @protected

   258      */

   259     _defAddFn: function(e) {

   260         var entries = this._entries,

   261             entry   = e.entry,

   262             max     = this.get("max"),

   263             pos;

   264 

   265         // If uniqueKeys is true and item exists with this key, then remove it.

   266         if (this.get("uniqueKeys")) {

   267             pos = this._position(e.entry.request);

   268             if (LANG.isValue(pos)) {

   269                 entries.splice(pos, 1);

   270             }

   271         }

   272 

   273         // If the cache at or over capacity, make room by removing stalest

   274         // element(s) starting at index-0.

   275         while (max && entries.length >= max) {

   276             entries.shift();

   277         }

   278 

   279         // Add entry to cache in the newest position, at the end of the array

   280         entries[entries.length] = entry;

   281     },

   282 

   283     /**

   284      * Flushes cache.

   285      *

   286      * @method _defFlushFn

   287      * @param e {Event.Facade} Event Facade object.

   288      * @protected

   289      */

   290     _defFlushFn: function(e) {

   291         var entries = this._entries,

   292             details = e.details[0],

   293             pos;

   294 

   295         //passed an item, flush only that

   296         if(details && LANG.isValue(details.request)) {

   297             pos = this._position(details.request);

   298 

   299             if(LANG.isValue(pos)) {

   300                 entries.splice(pos,1);

   301 

   302             }

   303         }

   304         //no item, flush everything

   305         else {

   306             this._entries = [];

   307         }

   308     },

   309 

   310     /**

   311      * Default overridable method compares current request with given cache entry.

   312      * Returns true if current request matches the cached request, otherwise

   313      * false. Implementers should override this method to customize the

   314      * cache-matching algorithm.

   315      *

   316      * @method _isMatch

   317      * @param request {Object} Request object.

   318      * @param entry {Object} Cached entry.

   319      * @return {Boolean} True if current request matches given cached request, false otherwise.

   320      * @protected

   321      */

   322     _isMatch: function(request, entry) {

   323         if(!entry.expires || new Date() < entry.expires) {

   324             return (request === entry.request);

   325         }

   326         return false;

   327     },

   328 

   329     /**

   330      * Returns position of a request in the entries array, otherwise null.

   331      *

   332      * @method _position

   333      * @param request {Object} Request object.

   334      * @return {Number} Array position if found, null otherwise.

   335      * @protected

   336      */

   337     _position: function(request) {

   338         // If cache is enabled...

   339         var entries = this._entries,

   340             length = entries.length,

   341             i = length-1;

   342 

   343         if((this.get("max") === null) || this.get("max") > 0) {

   344             // Loop through each cached entry starting from the newest

   345             for(; i >= 0; i--) {

   346                 // Execute matching function

   347                 if(this._isMatch(request, entries[i])) {

   348                     return i;

   349                 }

   350             }

   351         }

   352 

   353         return null;

   354     },

   355 

   356     /////////////////////////////////////////////////////////////////////////////

   357     //

   358     // Cache public methods

   359     //

   360     /////////////////////////////////////////////////////////////////////////////

   361 

   362     /**

   363      * Adds a new entry to the cache of the format

   364      * {request:request, response:response, cached:cached, expires:expires}.

   365      * If cache is full, evicts the stalest entry before adding the new one.

   366      *

   367      * @method add

   368      * @param request {Object} Request value.

   369      * @param response {Object} Response value.

   370      */

   371     add: function(request, response) {

   372         var expires = this.get("expires");

   373         if(this.get("initialized") && ((this.get("max") === null) || this.get("max") > 0) &&

   374                 (LANG.isValue(request) || LANG.isNull(request) || LANG.isUndefined(request))) {

   375             this.fire("add", {entry: {

   376                 request:request,

   377                 response:response,

   378                 cached: new Date(),

   379                 expires: isDate(expires) ? expires :

   380             (expires ? new Date(new Date().getTime() + this.get("expires")) : null)

   381             }});

   382         }

   383         else {

   384         }

   385     },

   386 

   387     /**

   388      * Flushes cache.

   389      *

   390      * @method flush

   391      */

   392     flush: function(request) {

   393         this.fire("flush", { request: (LANG.isValue(request) ? request : null) });

   394     },

   395 

   396     /**

   397      * Retrieves cached object for given request, if available, and refreshes

   398      * entry in the cache. Returns null if there is no cache match.

   399      *

   400      * @method retrieve

   401      * @param request {Object} Request object.

   402      * @return {Object} Cached object with the properties request and response, or null.

   403      */

   404     retrieve: function(request) {

   405         // If cache is enabled...

   406         var entries = this._entries,

   407             length = entries.length,

   408             entry = null,

   409             pos;

   410 

   411         if((length > 0) && ((this.get("max") === null) || (this.get("max") > 0))) {

   412             this.fire("request", {request: request});

   413 

   414             pos = this._position(request);

   415 

   416             if(LANG.isValue(pos)) {

   417                 entry = entries[pos];

   418 

   419                 this.fire("retrieve", {entry: entry});

   420 

   421                 // Refresh the position of the cache hit

   422                 if(pos < length-1) {

   423                     // Remove element from its original location

   424                     entries.splice(pos,1);

   425                     // Add as newest

   426                     entries[entries.length] = entry;

   427                 }

   428 

   429                 return entry;

   430             }

   431         }

   432         return null;

   433     }

   434 });

   435 

   436 Y.Cache = Cache;

   437 

   438 

   439 }, '3.10.3', {"requires": ["base"]});