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   1  /*
   2  YUI 3.17.2 (build 9c3c78e)
   3  Copyright 2014 Yahoo! Inc. All rights reserved.
   4  Licensed under the BSD License.
   5  http://yuilibrary.com/license/
   6  */
   7  
   8  YUI.add('cache-offline', function (Y, NAME) {
   9  
  10  /**
  11   * Provides a Cache subclass which uses HTML5 `localStorage` for persistence.
  12   *
  13   * @module cache
  14   * @submodule cache-offline
  15   */
  16  
  17  /**
  18   * Extends Cache utility with offline functionality.
  19   * @class CacheOffline
  20   * @extends Cache
  21   * @constructor
  22   */
  23  function CacheOffline() {
  24      CacheOffline.superclass.constructor.apply(this, arguments);
  25  }
  26  
  27  var localStorage = null,
  28      JSON = Y.JSON;
  29  
  30  // Bug 2529572
  31  try {
  32      localStorage = Y.config.win.localStorage;
  33  }
  34  catch(e) {
  35  }
  36  
  37  /////////////////////////////////////////////////////////////////////////////
  38  //
  39  // CacheOffline events
  40  //
  41  /////////////////////////////////////////////////////////////////////////////
  42  
  43  /**
  44  * @event error
  45  * @description Fired when an entry could not be added, most likely due to
  46  * exceeded browser quota.
  47  * <dl>
  48  * <dt>error (Object)</dt> <dd>The error object.</dd>
  49  * </dl>
  50  */
  51  
  52  /////////////////////////////////////////////////////////////////////////////
  53  //
  54  // CacheOffline static
  55  //
  56  /////////////////////////////////////////////////////////////////////////////
  57  Y.mix(CacheOffline, {
  58      /**
  59       * Class name.
  60       *
  61       * @property NAME
  62       * @type String
  63       * @static
  64       * @final
  65       * @value "cacheOffline"
  66       */
  67      NAME: "cacheOffline",
  68  
  69      ATTRS: {
  70          /////////////////////////////////////////////////////////////////////////////
  71          //
  72          // CacheOffline Attributes
  73          //
  74          /////////////////////////////////////////////////////////////////////////////
  75  
  76          /**
  77          * @attribute sandbox
  78          * @description A string that must be passed in via the constructor.
  79          * This identifier is used to sandbox one cache instance's entries
  80          * from another. Calling the cache instance's flush and length methods
  81          * or get("entries") will apply to only these sandboxed entries.
  82          * @type String
  83          * @default "default"
  84          * @initOnly
  85          */
  86          sandbox: {
  87              value: "default",
  88              writeOnce: "initOnly"
  89          },
  90  
  91          /**
  92          * @attribute expires
  93          * @description Absolute Date when data expires or
  94          * relative number of milliseconds. Zero disables expiration.
  95          * @type Date | Number
  96          * @default 86400000 (one day)
  97          */
  98          expires: {
  99              value: 86400000
 100          },
 101  
 102          /**
 103          * @attribute max
 104          * @description Disabled.
 105          * @readOnly
 106          * @default null
 107          */
 108          max: {
 109              value: null,
 110              readOnly: true
 111          },
 112  
 113          /**
 114          * @attribute uniqueKeys
 115          * @description Always true for CacheOffline.
 116          * @readOnly
 117          * @default true
 118          */
 119          uniqueKeys: {
 120              value: true,
 121              readOnly: true,
 122              setter: function() {
 123                  return true;
 124              }
 125          }
 126      },
 127  
 128      /**
 129       * Removes all items from all sandboxes. Useful if localStorage has
 130       * exceeded quota. Only supported on browsers that implement HTML 5
 131       * localStorage.
 132       *
 133       * @method flushAll
 134       * @static
 135       */
 136      flushAll: function() {
 137          var store = localStorage, key;
 138          if(store) {
 139              if(store.clear) {
 140                  store.clear();
 141              }
 142              // FF2.x and FF3.0.x
 143              else {
 144                  for (key in store) {
 145                      if (store.hasOwnProperty(key)) {
 146                          store.removeItem(key);
 147                          delete store[key];
 148                      }
 149                  }
 150              }
 151          }
 152          else {
 153          }
 154      }
 155  });
 156  
 157  Y.extend(CacheOffline, Y.Cache, localStorage ? {
 158  /////////////////////////////////////////////////////////////////////////////
 159  //
 160  // Offline is supported
 161  //
 162  /////////////////////////////////////////////////////////////////////////////
 163  
 164      /////////////////////////////////////////////////////////////////////////////
 165      //
 166      // CacheOffline protected methods
 167      //
 168      /////////////////////////////////////////////////////////////////////////////
 169      /**
 170       * Always return null.
 171       *
 172       * @method _setMax
 173       * @protected
 174       */
 175      _setMax: function(value) {
 176          return null;
 177      },
 178  
 179      /**
 180       * Gets size.
 181       *
 182       * @method _getSize
 183       * @protected
 184       */
 185      _getSize: function() {
 186          var count = 0,
 187              i=0,
 188              l=localStorage.length;
 189          for(; i<l; ++i) {
 190              // Match sandbox id
 191              if(localStorage.key(i).indexOf(this.get("sandbox")) === 0) {
 192                  count++;
 193              }
 194          }
 195          return count;
 196      },
 197  
 198      /**
 199       * Gets all entries.
 200       *
 201       * @method _getEntries
 202       * @protected
 203       */
 204      _getEntries: function() {
 205          var entries = [],
 206              i=0,
 207              l=localStorage.length,
 208              sandbox = this.get("sandbox");
 209          for(; i<l; ++i) {
 210              // Match sandbox id
 211              if(localStorage.key(i).indexOf(sandbox) === 0) {
 212                  entries[i] = JSON.parse(localStorage.key(i).substring(sandbox.length));
 213              }
 214          }
 215          return entries;
 216      },
 217  
 218      /**
 219       * Adds entry to cache.
 220       *
 221       * @method _defAddFn
 222       * @param e {EventFacade} Event Facade with the following properties:
 223       * <dl>
 224       * <dt>entry (Object)</dt> <dd>The cached entry.</dd>
 225       * </dl>
 226       * @protected
 227       */
 228      _defAddFn: function(e) {
 229          var entry = e.entry,
 230              request = entry.request,
 231              cached = entry.cached,
 232              expires = entry.expires;
 233  
 234          // Convert Dates to msecs on the way into localStorage
 235          entry.cached = cached.getTime();
 236          entry.expires = expires ? expires.getTime() : expires;
 237  
 238          try {
 239              localStorage.setItem(this.get("sandbox")+JSON.stringify({"request":request}), JSON.stringify(entry));
 240          }
 241          catch(error) {
 242              this.fire("error", {error:error});
 243          }
 244      },
 245  
 246      /**
 247       * Flushes cache.
 248       *
 249       * @method _defFlushFn
 250       * @param e {EventFacade} Event Facade object.
 251       * @protected
 252       */
 253      _defFlushFn: function(e) {
 254          var key,
 255              i=localStorage.length-1;
 256          for(; i>-1; --i) {
 257              // Match sandbox id
 258              key = localStorage.key(i);
 259              if(key.indexOf(this.get("sandbox")) === 0) {
 260                  localStorage.removeItem(key);
 261              }
 262          }
 263      },
 264  
 265      /////////////////////////////////////////////////////////////////////////////
 266      //
 267      // CacheOffline public methods
 268      //
 269      /////////////////////////////////////////////////////////////////////////////
 270      /**
 271       * Adds a new entry to the cache of the format
 272       * {request:request, response:response, cached:cached, expires: expires}.
 273       *
 274       * @method add
 275       * @param request {Object} Request value must be a String or JSON.
 276       * @param response {Object} Response value must be a String or JSON.
 277       */
 278  
 279      /**
 280       * Retrieves cached object for given request, if available.
 281       * Returns null if there is no cache match.
 282       *
 283       * @method retrieve
 284       * @param request {Object} Request object.
 285       * @return {Object} Cached object with the properties request, response,
 286       * and expires, or null.
 287       */
 288      retrieve: function(request) {
 289          this.fire("request", {request: request});
 290  
 291          var entry, expires, sandboxedrequest;
 292  
 293          try {
 294              sandboxedrequest = this.get("sandbox")+JSON.stringify({"request":request});
 295              try {
 296                  entry = JSON.parse(localStorage.getItem(sandboxedrequest));
 297              }
 298              catch(e) {
 299              }
 300          }
 301          catch(e2) {
 302          }
 303  
 304          if(entry) {
 305              // Convert msecs to Dates on the way out of localStorage
 306              entry.cached = new Date(entry.cached);
 307              expires = entry.expires;
 308              expires = !expires ? null : new Date(expires);
 309              entry.expires = expires;
 310  
 311              if(this._isMatch(request, entry)) {
 312                  this.fire("retrieve", {entry: entry});
 313                  return entry;
 314              }
 315          }
 316          return null;
 317      }
 318  } :
 319  /////////////////////////////////////////////////////////////////////////////
 320  //
 321  // Offline is not supported
 322  //
 323  /////////////////////////////////////////////////////////////////////////////
 324  {
 325      /**
 326       * Always return null.
 327       *
 328       * @method _setMax
 329       * @protected
 330       */
 331      _setMax: function(value) {
 332          return null;
 333      }
 334  });
 335  
 336  
 337  Y.CacheOffline = CacheOffline;
 338  
 339  
 340  }, '3.17.2', {"requires": ["cache-base", "json"]});