src/ng/cacheFactory.js
'use strict';
/**
* @ngdoc service
* @name $cacheFactory
* @this
*
* @description
* Factory that constructs {@link $cacheFactory.Cache Cache} objects and gives access to
* them.
*
* ```js
*
* var cache = $cacheFactory('cacheId');
* expect($cacheFactory.get('cacheId')).toBe(cache);
* expect($cacheFactory.get('noSuchCacheId')).not.toBeDefined();
*
* cache.put("key", "value");
* cache.put("another key", "another value");
*
* // We've specified no options on creation
* expect(cache.info()).toEqual({id: 'cacheId', size: 2});
*
* ```
*
*
* @param {string} cacheId Name or id of the newly created cache.
* @param {object=} options Options object that specifies the cache behavior. Properties:
*
* - `{number=}` `capacity` — turns the cache into LRU cache.
*
* @returns {object} Newly created cache object with the following set of methods:
*
* - `{object}` `info()` — Returns id, size, and options of cache.
* - `{{*}}` `put({string} key, {*} value)` — Puts a new key-value pair into the cache and returns
* it.
* - `{{*}}` `get({string} key)` — Returns cached value for `key` or undefined for cache miss.
* - `{void}` `remove({string} key)` — Removes a key-value pair from the cache.
* - `{void}` `removeAll()` — Removes all cached values.
* - `{void}` `destroy()` — Removes references to this cache from $cacheFactory.
*
* @example
<example module="cacheExampleApp" name="cache-factory">
<file name="index.html">
<div ng-controller="CacheController">
<input ng-model="newCacheKey" placeholder="Key">
<input ng-model="newCacheValue" placeholder="Value">
<button ng-click="put(newCacheKey, newCacheValue)">Cache</button>
<p ng-if="keys.length">Cached Values</p>
<div ng-repeat="key in keys">
<span ng-bind="key"></span>
<span>: </span>
<b ng-bind="cache.get(key)"></b>
</div>
<p>Cache Info</p>
<div ng-repeat="(key, value) in cache.info()">
<span ng-bind="key"></span>
<span>: </span>
<b ng-bind="value"></b>
</div>
</div>
</file>
<file name="script.js">
angular.module('cacheExampleApp', []).
controller('CacheController', ['$scope', '$cacheFactory', function($scope, $cacheFactory) {
$scope.keys = [];
$scope.cache = $cacheFactory('cacheId');
$scope.put = function(key, value) {
if (angular.isUndefined($scope.cache.get(key))) {
$scope.keys.push(key);
}
$scope.cache.put(key, angular.isUndefined(value) ? null : value);
};
}]);
</file>
<file name="style.css">
p {
margin: 10px 0 3px;
}
</file>
</example>
*/
function $CacheFactoryProvider() {
this.$get = function() {
var caches = {};
function cacheFactory(cacheId, options) {
if (cacheId in caches) {
throw minErr('$cacheFactory')('iid', 'CacheId \'{0}\' is already taken!', cacheId);
}
var size = 0,
stats = extend({}, options, {id: cacheId}),
data = createMap(),
capacity = (options && options.capacity) || Number.MAX_VALUE,
lruHash = createMap(),
freshEnd = null,
staleEnd = null;
/**
* @ngdoc type
* @name $cacheFactory.Cache
*
* @description
* A cache object used to store and retrieve data, primarily used by
* {@link $templateRequest $templateRequest} and the {@link ng.directive:script script}
* directive to cache templates and other data.
*
* ```js
* angular.module('superCache')
* .factory('superCache', ['$cacheFactory', function($cacheFactory) {
* return $cacheFactory('super-cache');
* }]);
* ```
*
* Example test:
*
* ```js
* it('should behave like a cache', inject(function(superCache) {
* superCache.put('key', 'value');
* superCache.put('another key', 'another value');
*
* expect(superCache.info()).toEqual({
* id: 'super-cache',
* size: 2
* });
*
* superCache.remove('another key');
* expect(superCache.get('another key')).toBeUndefined();
*
* superCache.removeAll();
* expect(superCache.info()).toEqual({
* id: 'super-cache',
* size: 0
* });
* }));
* ```
*/
return (caches[cacheId] = {
/**
* @ngdoc method
* @name $cacheFactory.Cache#put
* @kind function
*
* @description
* Inserts a named entry into the {@link $cacheFactory.Cache Cache} object to be
* retrieved later, and incrementing the size of the cache if the key was not already
* present in the cache. If behaving like an LRU cache, it will also remove stale
* entries from the set.
*
* It will not insert undefined values into the cache.
*
* @param {string} key the key under which the cached data is stored.
* @param {*} value the value to store alongside the key. If it is undefined, the key
* will not be stored.
* @returns {*} the value stored.
*/
put: function(key, value) {
if (isUndefined(value)) return;
if (capacity < Number.MAX_VALUE) {
var lruEntry = lruHash[key] || (lruHash[key] = {key: key});
refresh(lruEntry);
}
if (!(key in data)) size++;
data[key] = value;
if (size > capacity) {
this.remove(staleEnd.key);
}
return value;
},
/**
* @ngdoc method
* @name $cacheFactory.Cache#get
* @kind function
*
* @description
* Retrieves named data stored in the {@link $cacheFactory.Cache Cache} object.
*
* @param {string} key the key of the data to be retrieved
* @returns {*} the value stored.
*/
get: function(key) {
if (capacity < Number.MAX_VALUE) {
var lruEntry = lruHash[key];
if (!lruEntry) return;
refresh(lruEntry);
}
return data[key];
},
/**
* @ngdoc method
* @name $cacheFactory.Cache#remove
* @kind function
*
* @description
* Removes an entry from the {@link $cacheFactory.Cache Cache} object.
*
* @param {string} key the key of the entry to be removed
*/
remove: function(key) {
if (capacity < Number.MAX_VALUE) {
var lruEntry = lruHash[key];
if (!lruEntry) return;
if (lruEntry === freshEnd) freshEnd = lruEntry.p;
if (lruEntry === staleEnd) staleEnd = lruEntry.n;
link(lruEntry.n,lruEntry.p);
delete lruHash[key];
}
if (!(key in data)) return;
delete data[key];
size--;
},
/**
* @ngdoc method
* @name $cacheFactory.Cache#removeAll
* @kind function
*
* @description
* Clears the cache object of any entries.
*/
removeAll: function() {
data = createMap();
size = 0;
lruHash = createMap();
freshEnd = staleEnd = null;
},
/**
* @ngdoc method
* @name $cacheFactory.Cache#destroy
* @kind function
*
* @description
* Destroys the {@link $cacheFactory.Cache Cache} object entirely,
* removing it from the {@link $cacheFactory $cacheFactory} set.
*/
destroy: function() {
data = null;
stats = null;
lruHash = null;
delete caches[cacheId];
},
/**
* @ngdoc method
* @name $cacheFactory.Cache#info
* @kind function
*
* @description
* Retrieve information regarding a particular {@link $cacheFactory.Cache Cache}.
*
* @returns {object} an object with the following properties:
* <ul>
* <li>**id**: the id of the cache instance</li>
* <li>**size**: the number of entries kept in the cache instance</li>
* <li>**...**: any additional properties from the options object when creating the
* cache.</li>
* </ul>
*/
info: function() {
return extend({}, stats, {size: size});
}
});
/**
* makes the `entry` the freshEnd of the LRU linked list
*/
function refresh(entry) {
if (entry !== freshEnd) {
if (!staleEnd) {
staleEnd = entry;
} else if (staleEnd === entry) {
staleEnd = entry.n;
}
link(entry.n, entry.p);
link(entry, freshEnd);
freshEnd = entry;
freshEnd.n = null;
}
}
/**
* bidirectionally links two entries of the LRU linked list
*/
function link(nextEntry, prevEntry) {
if (nextEntry !== prevEntry) {
if (nextEntry) nextEntry.p = prevEntry; //p stands for previous, 'prev' didn't minify
if (prevEntry) prevEntry.n = nextEntry; //n stands for next, 'next' didn't minify
}
}
}
/**
* @ngdoc method
* @name $cacheFactory#info
*
* @description
* Get information about all the caches that have been created
*
* @returns {Object} - key-value map of `cacheId` to the result of calling `cache#info`
*/
cacheFactory.info = function() {
var info = {};
forEach(caches, function(cache, cacheId) {
info[cacheId] = cache.info();
});
return info;
};
/**
* @ngdoc method
* @name $cacheFactory#get
*
* @description
* Get access to a cache object by the `cacheId` used when it was created.
*
* @param {string} cacheId Name or id of a cache to access.
* @returns {object} Cache object identified by the cacheId or undefined if no such cache.
*/
cacheFactory.get = function(cacheId) {
return caches[cacheId];
};
return cacheFactory;
};
}
/**
* @ngdoc service
* @name $templateCache
* @this
*
* @description
* `$templateCache` is a {@link $cacheFactory.Cache Cache object} created by the
* {@link ng.$cacheFactory $cacheFactory}.
*
* The first time a template is used, it is loaded in the template cache for quick retrieval. You
* can load templates directly into the cache in a `script` tag, by using {@link $templateRequest},
* or by consuming the `$templateCache` service directly.
*
* Adding via the `script` tag:
*
* ```html
* <script type="text/ng-template" id="templateId.html">
* <p>This is the content of the template</p>
* </script>
* ```
*
* **Note:** the `script` tag containing the template does not need to be included in the `head` of
* the document, but it must be a descendent of the {@link ng.$rootElement $rootElement} (e.g.
* element with {@link ngApp} attribute), otherwise the template will be ignored.
*
* Adding via the `$templateCache` service:
*
* ```js
* var myApp = angular.module('myApp', []);
* myApp.run(function($templateCache) {
* $templateCache.put('templateId.html', 'This is the content of the template');
* });
* ```
*
* To retrieve the template later, simply use it in your component:
* ```js
* myApp.component('myComponent', {
* templateUrl: 'templateId.html'
* });
* ```
*
* or get it via the `$templateCache` service:
* ```js
* $templateCache.get('templateId.html')
* ```
*
*/
function $TemplateCacheProvider() {
this.$get = ['$cacheFactory', function($cacheFactory) {
return $cacheFactory('templates');
}];
}