Merge pull request #151 from twpayne/tile-cache-expiry

Tile cache expiry

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/debugtilesource.js

@@ -2,6 +2,7 @@ goog.provide('ol.source.DebugTileSource');
 
 goog.require('ol.Size');
 goog.require('ol.Tile');
+goog.require('ol.TileCache');
 goog.require('ol.TileCoord');
 goog.require('ol.source.TileSource');
 goog.require('ol.tilegrid.TileGrid');
@@ -94,26 +95,40 @@ ol.source.DebugTileSource = function(options) {
 
   /**
    * @private
-   * @type {Object.<string, ol.DebugTile_>}
-   * FIXME will need to expire elements from this cache
-   * FIXME see elemoine's work with goog.structs.LinkedMap
+   * @type {ol.TileCache}
    */
-  this.tileCache_ = {};
+  this.tileCache_ = new ol.TileCache();
 
 };
 goog.inherits(ol.source.DebugTileSource, ol.source.TileSource);
 
 
+/**
+ * @inheritDoc
+ */
+ol.source.DebugTileSource.prototype.canExpireCache = function() {
+  return this.tileCache_.canExpireCache();
+};
+
+
+/**
+ * @inheritDoc
+ */
+ol.source.DebugTileSource.prototype.expireCache = function(usedTiles) {
+  this.tileCache_.expireCache(usedTiles);
+};
+
+
 /**
  * @inheritDoc
  */
 ol.source.DebugTileSource.prototype.getTile = function(tileCoord) {
   var key = tileCoord.toString();
-  if (goog.object.containsKey(this.tileCache_, key)) {
-    return this.tileCache_[key];
+  if (this.tileCache_.containsKey(key)) {
+    return /** @type {ol.DebugTile_} */ (this.tileCache_.get(key));
   } else {
     var tile = new ol.DebugTile_(tileCoord, this.tileGrid);
-    this.tileCache_[key] = tile;
+    this.tileCache_.set(key, tile);
     return tile;
   }
 };

src/ol/source/imagetilesource.js

@@ -5,6 +5,7 @@ goog.require('ol.Attribution');
 goog.require('ol.Extent');
 goog.require('ol.ImageTile');
 goog.require('ol.Projection');
+goog.require('ol.TileCache');
 goog.require('ol.TileCoord');
 goog.require('ol.TileUrlFunction');
 goog.require('ol.TileUrlFunctionType');
@@ -55,32 +56,46 @@ ol.source.ImageTileSource = function(options) {
 
   /**
    * @private
-   * @type {Object.<string, ol.ImageTile>}
-   * FIXME will need to expire elements from this cache
-   * FIXME see elemoine's work with goog.structs.LinkedMap
+   * @type {ol.TileCache}
    */
-  this.tileCache_ = {};
+  this.tileCache_ = new ol.TileCache();
 
 };
 goog.inherits(ol.source.ImageTileSource, ol.source.TileSource);
 
 
+/**
+ * @inheritDoc
+ */
+ol.source.ImageTileSource.prototype.canExpireCache = function() {
+  return this.tileCache_.canExpireCache();
+};
+
+
+/**
+ * @inheritDoc
+ */
+ol.source.ImageTileSource.prototype.expireCache = function(usedTiles) {
+  this.tileCache_.expireCache(usedTiles);
+};
+
+
 /**
  * @inheritDoc
  */
 ol.source.ImageTileSource.prototype.getTile = function(tileCoord) {
   var key = tileCoord.toString();
-  if (goog.object.containsKey(this.tileCache_, key)) {
-    return this.tileCache_[key];
+  if (this.tileCache_.containsKey(key)) {
+    return /** @type {ol.Tile} */ (this.tileCache_.get(key));
   } else {
     var tileUrl = this.getTileCoordUrl(tileCoord);
     var tile;
     if (goog.isDef(tileUrl)) {
       tile = new ol.ImageTile(tileCoord, tileUrl, this.crossOrigin_);
+      this.tileCache_.set(key, tile);
     } else {
       tile = null;
     }
-    this.tileCache_[key] = tile;
     return tile;
   }
 };

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
  */

src/ol/tilecache.js

@@ -0,0 +1,58 @@
+goog.provide('ol.TileCache');
+
+goog.require('goog.dispose');
+goog.require('goog.structs.LinkedMap');
+goog.require('ol.Tile');
+goog.require('ol.TileRange');
+
+
+/**
+ * @define {number} Default high water mark.
+ */
+ol.DEFAULT_TILE_CACHE_HIGH_WATER_MARK = 512;
+
+
+
+/**
+ * @constructor
+ * @extends {goog.structs.LinkedMap}
+ * @param {number=} opt_highWaterMark High water mark.
+ */
+ol.TileCache = function(opt_highWaterMark) {
+
+  goog.base(this, undefined, true);
+
+  /**
+   * @private
+   * @type {number}
+   */
+  this.highWaterMark_ = goog.isDef(opt_highWaterMark) ?
+      opt_highWaterMark : ol.DEFAULT_TILE_CACHE_HIGH_WATER_MARK;
+
+};
+goog.inherits(ol.TileCache, goog.structs.LinkedMap);
+
+
+/**
+ * @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 = /** @type {ol.Tile} */ (this.peekLast());
+    zKey = tile.tileCoord.z.toString();
+    if (zKey in usedTiles && usedTiles[zKey].contains(tile.tileCoord)) {
+      break;
+    } else {
+      this.pop();
+    }
+  }
+};