openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
50 lines (39 loc) • 1.03 kB
JavaScript
goog.provide('ol.TileCache');
goog.require('ol');
goog.require('ol.structs.LRUCache');
/**
* @constructor
* @extends {ol.structs.LRUCache.<ol.Tile>}
* @param {number=} opt_highWaterMark High water mark.
* @struct
*/
ol.TileCache = function(opt_highWaterMark) {
ol.structs.LRUCache.call(this);
/**
* @private
* @type {number}
*/
this.highWaterMark_ = opt_highWaterMark !== undefined ? opt_highWaterMark : 2048;
};
ol.inherits(ol.TileCache, ol.structs.LRUCache);
/**
* @return {boolean} Can expire cache.
*/
ol.TileCache.prototype.canExpireCache = function() {
return this.getCount() > this.highWaterMark_;
};
/**
* @param {Object.<string, ol.TileRange>} usedTiles Used tiles.
*/
ol.TileCache.prototype.expireCache = function(usedTiles) {
var tile, zKey;
while (this.canExpireCache()) {
tile = this.peekLast();
zKey = tile.tileCoord[0].toString();
if (zKey in usedTiles && usedTiles[zKey].contains(tile.tileCoord)) {
break;
} else {
this.pop().dispose();
}
}
};