projects / extjs.git / blame
| Commit | Line | Data |
|---|---|---|
| 6527f429 DM |
1 | /**\r |
| 2 | * Limited cache is a size limited cache container that stores limited number of objects.\r | |
| 3 | * \r | |
| 4 | * When {@link #get} is called, the container will try to find the object in the list.\r | |
| 5 | * If failed it will call the {@link #feeder} to create that object. If there are too many\r | |
| 6 | * objects in the container, the old ones are removed.\r | |
| 7 | * \r | |
| 8 | * __Note:__ This is not using a Least Recently Used policy due to simplicity and performance consideration.\r | |
| 9 | * @private\r | |
| 10 | */\r | |
| 11 | Ext.define('Ext.draw.LimitedCache', {\r | |
| 12 | \r | |
| 13 | config: {\r | |
| 14 | /**\r | |
| 15 | * @cfg {Number}\r | |
| 16 | * The amount limit of the cache.\r | |
| 17 | */\r | |
| 18 | limit: 40,\r | |
| 19 | \r | |
| 20 | /**\r | |
| 21 | * @cfg {Function}\r | |
| 22 | * Function that generates the object when look-up failed.\r | |
| 23 | * @return {Number}\r | |
| 24 | */\r | |
| 25 | feeder: function () {\r | |
| 26 | return 0;\r | |
| 27 | },\r | |
| 28 | \r | |
| 29 | /**\r | |
| 30 | * @cfg {Object}\r | |
| 31 | * The scope for {@link #feeder}\r | |
| 32 | */\r | |
| 33 | scope: null\r | |
| 34 | },\r | |
| 35 | \r | |
| 36 | cache: null,\r | |
| 37 | \r | |
| 38 | constructor: function (config) {\r | |
| 39 | this.cache = {};\r | |
| 40 | this.cache.list = [];\r | |
| 41 | this.cache.tail = 0;\r | |
| 42 | this.initConfig(config);\r | |
| 43 | },\r | |
| 44 | \r | |
| 45 | /**\r | |
| 46 | * Get a cached object.\r | |
| 47 | * @param {String} id\r | |
| 48 | * @param {Mixed...} args Arguments appended to feeder.\r | |
| 49 | * @return {Object}\r | |
| 50 | */\r | |
| 51 | get: function (id) {\r | |
| 52 | // TODO: Implement cache hit optimization\r | |
| 53 | var cache = this.cache,\r | |
| 54 | limit = this.getLimit(),\r | |
| 55 | feeder = this.getFeeder(),\r | |
| 56 | scope = this.getScope() || this;\r | |
| 57 | \r | |
| 58 | if (cache[id]) {\r | |
| 59 | return cache[id].value;\r | |
| 60 | }\r | |
| 61 | if (cache.list[cache.tail]) {\r | |
| 62 | delete cache[cache.list[cache.tail].cacheId];\r | |
| 63 | }\r | |
| 64 | cache[id] = cache.list[cache.tail] = {\r | |
| 65 | value: feeder.apply(scope, Array.prototype.slice.call(arguments, 1)),\r | |
| 66 | cacheId: id\r | |
| 67 | };\r | |
| 68 | cache.tail++;\r | |
| 69 | if (cache.tail === limit) {\r | |
| 70 | cache.tail = 0;\r | |
| 71 | }\r | |
| 72 | return cache[id].value;\r | |
| 73 | },\r | |
| 74 | \r | |
| 75 | /**\r | |
| 76 | * Clear all the objects.\r | |
| 77 | */\r | |
| 78 | clear: function () {\r | |
| 79 | this.cache = {};\r | |
| 80 | this.cache.list = [];\r | |
| 81 | this.cache.tail = 0;\r | |
| 82 | }\r | |
| 83 | });\r |