cache.js revision 4e2030f05d0777a728f566f7cebbd99721b26dda
YUI.add('cache-base', function(Y) {
/**
* The Cache utility provides a common configurable interface for components to
* cache and retrieve data from a local JavaScript struct.
*
* @module cache
*/
var LANG = Y.Lang,
/**
* Base class for the YUI Cache utility.
* @class Cache
* @extends Base
* @constructor
*/
Cache = function() {
Cache.superclass.constructor.apply(this, arguments);
};
/////////////////////////////////////////////////////////////////////////////
//
// Cache static properties
//
/////////////////////////////////////////////////////////////////////////////
Y.mix(Cache, {
/**
* Class name.
*
* @property NAME
* @type String
* @static
* @final
* @value "cache"
*/
NAME: "cache",
ATTRS: {
/////////////////////////////////////////////////////////////////////////////
//
// Cache Attributes
//
/////////////////////////////////////////////////////////////////////////////
/**
* @attribute max
* @description Maximum number of entries the Cache can hold.
* Set to 0 to turn off caching.
* @type Number
* @default 0
*/
max: {
value: 0,
setter: "_setMax"
},
/**
* @attribute size
* @description Number of entries currently cached.
* @type Number
*/
size: {
readOnly: true,
getter: "_getSize"
},
/**
* @attribute uniqueKeys
* @description Validate uniqueness of stored keys. Default is false and
* is more performant.
* @type Boolean
*/
uniqueKeys: {
value: false
},
/**
* @attribute entries
* @description Cached entries.
* @type Array
*/
entries: {
readOnly: true,
getter: "_getEntries"
}
}
});
Y.extend(Cache, Y.Base, {
/////////////////////////////////////////////////////////////////////////////
//
// Cache private properties
//
/////////////////////////////////////////////////////////////////////////////
/**
* Array of request/response objects indexed chronologically.
*
* @property _entries
* @type Object[]
* @private
*/
_entries: null,
/////////////////////////////////////////////////////////////////////////////
//
// Cache private methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* @method initializer
* @description Internal init() handler.
* @param config {Object} Config object.
* @private
*/
initializer: function(config) {
/**
* @event add
* @description Fired when an entry is added.
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>entry (Object)</dt> <dd>The cached entry.</dd>
* </dl>
* @preventable _defAddFn
*/
this.publish("add", {defaultFn: this._defAddFn});
/**
* @event flush
* @description Fired when the cache is flushed.
* @param e {Event.Facade} Event Facade object.
* @preventable _defFlushFn
*/
this.publish("flush", {defaultFn: this._defFlushFn});
/**
* @event request
* @description Fired when an entry is requested from the cache.
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>request (Object)</dt> <dd>The request object.</dd>
* </dl>
*/
/**
* @event retrieve
* @description Fired when an entry is retrieved from the cache.
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>entry (Object)</dt> <dd>The retrieved entry.</dd>
* </dl>
*/
// Initialize internal values
this._entries = [];
},
/**
* @method destructor
* @description Internal destroy() handler.
* @private
*/
destructor: function() {
this._entries = [];
},
/////////////////////////////////////////////////////////////////////////////
//
// Cache protected methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Sets max.
*
* @method _setMax
* @protected
*/
_setMax: function(value) {
// If the cache is full, make room by removing stalest element (index=0)
var entries = this._entries;
if(value > 0) {
if(entries) {
while(entries.length > value) {
entries.shift();
}
}
}
else {
value = 0;
this._entries = [];
}
return value;
},
/**
* Gets size.
*
* @method _getSize
* @protected
*/
_getSize: function() {
return this._entries.length;
},
/**
* Gets all entries.
*
* @method _getEntries
* @protected
*/
_getEntries: function() {
return this._entries;
},
/**
* Adds entry to cache.
*
* @method _defAddFn
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>entry (Object)</dt> <dd>The cached entry.</dd>
* </dl>
* @protected
*/
_defAddFn: function(e) {
var entries = this._entries,
max = this.get("max"),
entry = e.entry;
if(this.get("uniqueKeys") && (this.retrieve(e.entry.request))) {
entries.shift();
}
// If the cache at or over capacity, make room by removing stalest element (index=0)
while(max && entries.length>=max) {
entries.shift();
}
// Add entry to cache in the newest position, at the end of the array
entries[entries.length] = entry;
},
/**
* Flushes cache.
*
* @method _defFlushFn
* @param e {Event.Facade} Event Facade object.
* @protected
*/
_defFlushFn: function(e) {
this._entries = [];
},
/**
* Default overridable method compares current request with given cache entry.
* Returns true if current request matches the cached request, otherwise
* false. Implementers should override this method to customize the
* cache-matching algorithm.
*
* @method _isMatch
* @param request {Object} Request object.
* @param entry {Object} Cached entry.
* @return {Boolean} True if current request matches given cached request, false otherwise.
* @protected
*/
_isMatch: function(request, entry) {
return (request === entry.request);
},
/////////////////////////////////////////////////////////////////////////////
//
// Cache public methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Adds a new entry to the cache of the format
* {request:request, response:response}.
* If cache is full, evicts the stalest entry before adding the new one.
*
* @method add
* @param request {Object} Request value.
* @param response {Object} Response value.
*/
add: function(request, response) {
if(this.get("initialized") && ((this.get("max") === null) || this.get("max") > 0) &&
(LANG.isValue(request) || LANG.isNull(request) || LANG.isUndefined(request))) {
this.fire("add", {entry: {request:request, response:response, cached: new Date()}});
}
else {
}
},
/**
* Flushes cache.
*
* @method flush
*/
flush: function() {
this.fire("flush");
},
/**
* Retrieves cached object for given request, if available, and refreshes
* entry in the cache. Returns null if there is no cache match.
*
* @method retrieve
* @param request {Object} Request object.
* @return {Object} Cached object with the properties request and response, or null.
*/
retrieve: function(request) {
// If cache is enabled...
var entries = this._entries,
length = entries.length,
entry = null,
i = length-1;
if((length > 0) && ((this.get("max") === null) || (this.get("max") > 0))) {
this.fire("request", {request: request});
// Loop through each cached entry starting from the newest
for(; i >= 0; i--) {
entry = entries[i];
// Execute matching function
if(this._isMatch(request, entry)) {
this.fire("retrieve", {entry: entry});
// Refresh the position of the cache hit
if(i < length-1) {
// Remove element from its original location
entries.splice(i,1);
// Add as newest
entries[entries.length] = entry;
}
return entry;
}
}
}
return null;
}
});
Y.Cache = Cache;
}, '@VERSION@' ,{requires:['base']});
YUI.add('cache-offline', function(Y) {
/**
* Extends Cache utility with offline functionality.
* @class CacheOffline
* @extends Cache
* @constructor
*/
function CacheOffline() {
CacheOffline.superclass.constructor.apply(this, arguments);
}
var localStorage = Y.config.win.localStorage,
isDate = Y.Lang.isDate,
JSON = Y.JSON,
/////////////////////////////////////////////////////////////////////////////
//
// CacheOffline static properties
//
/////////////////////////////////////////////////////////////////////////////
cacheOfflineStatic = {
/**
* Class name.
*
* @property NAME
* @type String
* @static
* @final
* @value "cacheOffline"
*/
NAME: "cacheOffline",
ATTRS: {
/////////////////////////////////////////////////////////////////////////////
//
// CacheOffline Attributes
//
/////////////////////////////////////////////////////////////////////////////
/**
* @attribute sandbox
* @description A string that must be passed in via the constructor.
* This identifier is used to sandbox one cache instance's entries
* from another. Calling the cache instance's flush and length methods
* or get("entries") will apply to only these sandboxed entries.
* @type String
* @default "default"
* @initOnly
*/
sandbox: {
value: "default",
writeOnce: "initOnly"
},
/**
* @attribute expires
* @description Absolute Date when data expires or
* relative number of milliseconds. Zero disables expiration.
* @type Date | Number
* @default 0
*/
expires: {
value: 86400000, //one day
validator: function(v) {
return Y.Lang.isDate(v) || (Y.Lang.isNumber(v) && v >= 0);
}
},
/**
* @attribute max
* @description Disabled.
* @readOnly
* @default null
*/
max: {
value: null,
readOnly: true
},
/**
* @attribute uniqueKeys
* @description Always true for CacheOffline.
* @readOnly
* @default true
*/
uniqueKeys: {
value: true,
readOnly: true,
setter: function() {
return true;
}
}
},
/**
* Removes all items from all sandboxes. Useful if localStorage has
* exceeded quota. Only supported on browsers that implement HTML 5
* localStorage.
*
* @method flushAll
* @static
*/
flushAll: function() {
var store = localStorage, key;
if(store) {
if(store.clear) {
store.clear();
}
// FF2.x and FF3.0.x
else {
for (key in store) {
if (store.hasOwnProperty(key)) {
store.removeItem(key);
delete store[key];
}
}
}
}
else {
}
}
},
/////////////////////////////////////////////////////////////////////////////
//
// CacheOffline events
//
/////////////////////////////////////////////////////////////////////////////
/**
* @event error
* @description Fired when an entry could not be added, most likely due to
* exceeded browser quota.
* <dl>
* <dt>error (Object)</dt> <dd>The error object.</dd>
* </dl>
*/
cacheOfflinePrototype = localStorage ? {
/////////////////////////////////////////////////////////////////////////////
//
// CacheOffline protected methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Always return null.
*
* @method _setMax
* @protected
*/
_setMax: function(value) {
return null;
},
/**
* Gets size.
*
* @method _getSize
* @protected
*/
_getSize: function() {
var count = 0,
i=0,
l=localStorage.length;
for(; i<l; ++i) {
// Match sandbox id
if(localStorage.key(i).indexOf(this.get("sandbox")) === 0) {
count++;
}
}
return count;
},
/**
* Gets all entries.
*
* @method _getEntries
* @protected
*/
_getEntries: function() {
var entries = [],
i=0,
l=localStorage.length,
sandbox = this.get("sandbox");
for(; i<l; ++i) {
// Match sandbox id
if(localStorage.key(i).indexOf(sandbox) === 0) {
entries[i] = JSON.parse(localStorage.key(i).substring(sandbox.length));
}
}
return entries;
},
/**
* Adds entry to cache.
*
* @method _defAddFn
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>entry (Object)</dt> <dd>The cached entry.</dd>
* </dl>
* @protected
*/
_defAddFn: function(e) {
var entry = e.entry,
request = entry.request,
expires = this.get("expires");
entry.expires = isDate(expires) ? expires :
(expires ? new Date(new Date().getTime() + this.get("expires")) : null);
try {
localStorage.setItem(this.get("sandbox")+JSON.stringify({"request":request}), JSON.stringify(entry));
}
catch(error) {
this.fire("error", {error:error});
}
},
/**
* Flushes cache.
*
* @method _defFlushFn
* @param e {Event.Facade} Event Facade object.
* @protected
*/
_defFlushFn: function(e) {
var key,
i=localStorage.length-1;
for(; i>-1; --i) {
// Match sandbox id
key = localStorage.key(i);
if(key.indexOf(this.get("sandbox")) === 0) {
localStorage.removeItem(key);
}
}
},
/////////////////////////////////////////////////////////////////////////////
//
// CacheOffline public methods
//
/////////////////////////////////////////////////////////////////////////////
/**
* Adds a new entry to the cache of the format
* {request:request, response:response, expires: expires}.
*
* @method add
* @param request {Object} Request value must be a String or JSON.
* @param response {Object} Response value must be a String or JSON.
*/
/**
* Retrieves cached object for given request, if available.
* Returns null if there is no cache match.
*
* @method retrieve
* @param request {Object} Request object.
* @return {Object} Cached object with the properties request, response,
* and expires, or null.
*/
retrieve: function(request) {
this.fire("request", {request: request});
var entry, expires, cached;
try {
request = this.get("sandbox")+JSON.stringify({"request":request});
try {
entry = JSON.parse(localStorage.getItem(request));
}
catch(e) {
}
}
catch(e2) {
}
if(entry) {
entry.cached = new Date(entry.cached);
expires = entry.expires;
expires = !expires ? null : new Date(expires);
if(!expires || new Date() < expires) {
entry.expires = expires;
this.fire("retrieve", {entry: entry});
return entry;
}
}
return null;
}
} : {
/**
* Always return null.
*
* @method _setMax
* @protected
*/
_setMax: function(value) {
return null;
},
/**
* Adds entry to cache with an expires property.
*
* @method _defAddFn
* @param e {Event.Facade} Event Facade with the following properties:
* <dl>
* <dt>entry (Object)</dt> <dd>The cached entry.</dd>
* </dl>
* @protected
*/
_defAddFn: function(e) {
var expires = this.get("expires");
e.entry.expires = isDate(expires) ? expires :
(expires ? new Date(new Date().getTime() + this.get("expires")) : null);
CacheOffline.superclass._defAddFn.call(this, e);
},
/**
* Overrides the default method to check for expired entry.
* Returns true if current request matches the cached request, otherwise
* false. Implementers should override this method to customize the
* cache-matching algorithm.
*
* @method _isMatch
* @param request {Object} Request object.
* @param entry {Object} Cached entry.
* @return {Boolean} True if current request matches given cached request
* and entry has not expired, false otherwise.
* @protected
*/
_isMatch: function(request, entry) {
if(!entry.expires || new Date() < entry.expires) {
return (request === entry.request);
}
return false;
}
};
Y.mix(CacheOffline, cacheOfflineStatic);
Y.extend(CacheOffline, Y.Cache, cacheOfflinePrototype);
Y.CacheOffline = CacheOffline;
}, '@VERSION@' ,{requires:['cache-base', 'json']});
YUI.add('cache', function(Y){}, '@VERSION@' ,{use:['cache-base','cache-offline']});