CacheEntry.js

//-----------------------------------------------------------------------------
/**
 * The resource class. Allows to be collected as a garbage if not use for some time or ticks
 *
 * @class CacheEntry
 * @constructor
 * @param {ResourceManager} resource manager
 * @param {string} key, url of the resource
 * @param {string} item - Bitmap, HTML5Audio, WebAudio - whatever you want to store in the cache
 */
function CacheEntry(cache, key, item) {
    this.cache = cache;
    this.key = key;
    this.item = item;
    this.cached = false;
    this.touchTicks = 0;
    this.touchSeconds = 0;
    this.ttlTicks = 0;
    this.ttlSeconds = 0;
    this.freedByTTL = false;
}

/**
 * frees the resource
 */
CacheEntry.prototype.free = function (byTTL) {
    this.freedByTTL = byTTL || false;
    if (this.cached) {
        this.cached = false;
        delete this.cache._inner[this.key];
    }
};

/**
 * Allocates the resource
 * @returns {CacheEntry}
 */
CacheEntry.prototype.allocate = function () {
    if (!this.cached) {
        this.cache._inner[this.key] = this;
        this.cached = true;
    }
    this.touch();
    return this;
};

/**
 * Sets the time to live
 * @param {number} ticks TTL in ticks, 0 if not set
 * @param {number} time TTL in seconds, 0 if not set
 * @returns {CacheEntry}
 */
CacheEntry.prototype.setTimeToLive = function (ticks, seconds) {
    this.ttlTicks = ticks || 0;
    this.ttlSeconds = seconds || 0;
    return this;
};

CacheEntry.prototype.isStillAlive = function () {
    var cache = this.cache;
    return ((this.ttlTicks == 0) || (this.touchTicks + this.ttlTicks < cache.updateTicks )) &&
        ((this.ttlSeconds == 0) || (this.touchSeconds + this.ttlSeconds < cache.updateSeconds ));
};

/**
 * makes sure that resource wont freed by Time To Live
 * if resource was already freed by TTL, put it in cache again
 */
CacheEntry.prototype.touch = function () {
    var cache = this.cache;
    if (this.cached) {
        this.touchTicks = cache.updateTicks;
        this.touchSeconds = cache.updateSeconds;
    } else if (this.freedByTTL) {
        this.freedByTTL = false;
        if (!cache._inner[this.key]) {
            cache._inner[this.key] = this;
        }
    }
};