Add tile cache expiry infrastructure

src/ol/renderer/canvas/canvastilelayerrenderer.js

@@ -219,6 +219,7 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
   }
 
   this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
+  this.scheduleExpireCache(frameState, tileSource);
 
   var transform = this.transform_;
   goog.vec.Mat4.makeIdentity(transform);

src/ol/renderer/dom/domtilelayerrenderer.js

@@ -239,6 +239,7 @@ ol.renderer.dom.TileLayer.prototype.renderFrame =
   }
 
   this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
+  this.scheduleExpireCache(frameState, tileSource);
 
 };
 

src/ol/renderer/layerrenderer.js

@@ -2,10 +2,12 @@ goog.provide('ol.renderer.Layer');
 
 goog.require('goog.events');
 goog.require('goog.events.EventType');
+goog.require('ol.FrameState');
 goog.require('ol.Object');
 goog.require('ol.TileRange');
 goog.require('ol.layer.Layer');
 goog.require('ol.layer.LayerProperty');
+goog.require('ol.source.TileSource');
 
 
 
@@ -128,6 +130,23 @@ ol.renderer.Layer.prototype.handleLayerSaturationChange = goog.nullFunction;
 ol.renderer.Layer.prototype.handleLayerVisibleChange = goog.nullFunction;
 
 
+/**
+ * @protected
+ * @param {ol.FrameState} frameState Frame state.
+ * @param {ol.source.TileSource} tileSource Tile source.
+ */
+ol.renderer.Layer.prototype.scheduleExpireCache =
+    function(frameState, tileSource) {
+  if (tileSource.canExpireCache()) {
+    frameState.postRenderFunctions.push(
+        goog.partial(function(tileSource, map, frameState) {
+          var tileSourceKey = goog.getUid(tileSource).toString();
+          tileSource.expireCache(frameState.usedTiles[tileSourceKey]);
+        }, tileSource));
+  }
+};
+
+
 /**
  * @protected
  * @param {Object.<string, Object.<string, ol.TileRange>>} usedTiles Used tiles.

src/ol/renderer/webgl/webgltilelayerrenderer.js

@@ -462,6 +462,7 @@ ol.renderer.webgl.TileLayer.prototype.renderFrame =
   }
 
   this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
+  this.scheduleExpireCache(frameState, tileSource);
 
   goog.vec.Mat4.makeIdentity(this.matrix_);
   goog.vec.Mat4.translate(this.matrix_,

src/ol/source/tilesource.js

@@ -1,6 +1,7 @@
 goog.provide('ol.source.TileSource');
 goog.provide('ol.source.TileSourceOptions');
 
+goog.require('goog.functions');
 goog.require('ol.Attribution');
 goog.require('ol.Extent');
 goog.require('ol.Projection');
@@ -46,6 +47,18 @@ ol.source.TileSource = function(tileSourceOptions) {
 goog.inherits(ol.source.TileSource, ol.source.Source);
 
 
+/**
+ * @return {boolean} Can expire cache.
+ */
+ol.source.TileSource.prototype.canExpireCache = goog.functions.FALSE;
+
+
+/**
+ * @param {Object.<string, ol.TileRange>} usedTiles Used tiles.
+ */
+ol.source.TileSource.prototype.expireCache = goog.abstractMethod;
+
+
 /**
  * @inheritDoc
  */