Fix wrong test comparison. Add equality comparator to TileSource API. Return

deprecated support for getCompletionCallback. Turn on zombie cache if sources replaced & equal.

src/dzitilesource.js

@@ -167,6 +167,14 @@ $.extend( $.DziTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
     },
 
 
+    /**
+     * Equality comparator
+     */
+    equals: function(otherSource) {
+        return this.tilesUrl === otherSource.tilesUrl;
+    },
+
+
     /**
      * @function
      * @param {Number} level

src/iiiftilesource.js

@@ -503,6 +503,13 @@ $.extend( $.IIIFTileSource.prototype, $.TileSource.prototype, /** @lends OpenSea
         return uri;
     },
 
+    /**
+     * Equality comparator
+     */
+    equals: function(otherSource) {
+        return this._id === otherSource._id;
+    },
+
     __testonly__: {
         canBeTiled: canBeTiled,
         constructLevels: constructLevels

src/imagetilesource.js

@@ -180,6 +180,13 @@ $.ImageTileSource = class extends $.TileSource {
         return `${this.url}?l=${level}&x=${x}&y=${y}`;
     }
 
+    /**
+     * Equality comparator
+     */
+    equals(otherSource) {
+        return this.url === otherSource.url;
+    }
+
     getTilePostData(level, x, y) {
         return {level: level, x: x, y: y};
     }

src/legacytilesource.js

@@ -187,6 +187,21 @@ $.extend( $.LegacyTileSource.prototype, $.TileSource.prototype, /** @lends OpenS
             url = this.levels[ level ].url;
         }
         return url;
+    },
+
+    /**
+     * Equality comparator
+     */
+    equals: function (otherSource) {
+        if (!otherSource.levels || otherSource.levels.length !== this.levels.length) {
+            return false;
+        }
+        for (let i = this.minLevel; i <= this.maxLevel; i++) {
+            if (this.levels[i].url !== otherSource.levels[i].url) {
+                return false;
+            }
+        }
+        return true;
     }
 } );
 

src/osmtilesource.js

@@ -139,6 +139,13 @@ $.extend( $.OsmTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
      */
     getTileUrl: function( level, x, y ) {
         return this.tilesUrl + (level - 8) + "/" + x + "/" + y + ".png";
+    },
+
+    /**
+     * Equality comparator
+     */
+    equals: function(otherSource) {
+        return this.tilesUrl === otherSource.tilesUrl;
     }
 });
 

src/tiledimage.js

@@ -1785,13 +1785,19 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
         // -> reason why it is not in the constructor
         tile.setCache(tile.cacheKey, data, dataType, false, cutoff);
 
-        let resolver = null;
+        let resolver = null,
+            increment = 0,
+            eventFinished = false;
         const _this = this,
             finishPromise = new $.Promise(r => {
                 resolver = r;
             });
 
         function completionCallback() {
+            increment--;
+            if (increment > 0) {
+                return;
+            }
             //do not override true if set (false is default)
             tile.hasTransparency = tile.hasTransparency || _this.source.hasTransparency(
                 undefined, tile.getUrl(), tile.ajaxHeaders, tile.postData
@@ -1823,6 +1829,17 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
             tile.save();
         }
 
+        function getCompletionCallback() {
+            if (eventFinished) {
+                $.console.error("Event 'tile-loaded' argument getCompletionCallback must be called synchronously. " +
+                    "Its return value should be called asynchronously.");
+            }
+            increment++;
+            return completionCallback;
+        }
+
+        const fallbackCompletion = getCompletionCallback();
+
         /**
          * Triggered when a tile has just been loaded in memory. That means that the
          * image has been downloaded and can be modified before being drawn to the canvas.
@@ -1841,7 +1858,7 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
          * @property {OpenSeadragon.Promise} - Promise resolved when the tile gets fully loaded.
          * @property {function} getCompletionCallback - deprecated
          */
-        const promise = this.viewer.raiseEventAwaiting("tile-loaded", {
+        this.viewer.raiseEventAwaiting("tile-loaded", {
             tile: tile,
             tiledImage: this,
             tileRequest: tileRequest,
@@ -1855,13 +1872,15 @@ $.extend($.TiledImage.prototype, $.EventSource.prototype, /** @lends OpenSeadrag
                 return data;
             },
             getCompletionCallback: function () {
-                $.console.error("[tile-loaded] getCompletionCallback is not supported: it is compulsory to handle the event with async functions if applicable.");
+                $.console.error("[tile-loaded] getCompletionCallback is deprecated: it introduces race conditions: " +
+                    "use async event handlers instead, execution order is deducted by addHandler(...) priority");
+                return getCompletionCallback();
             },
-        });
-        promise.then(completionCallback).catch(() => {
+        }).catch(() => {
             $.console.error("[tile-loaded] event finished with failure: there might be a problem with a plugin you are using.");
-            completionCallback();
-        });
+        }).then(() => {
+            eventFinished = true;
+        }).then(fallbackCompletion);
     },
 
     /**

src/tilesource.js

@@ -591,6 +591,17 @@ $.TileSource.prototype = {
         return false;
     },
 
+    /**
+     * Check whether two tileSources are equal. This is used for example
+     * when replacing tile-sources, which turns on the zombie cache before
+     * old item removal.
+     * @param {OpenSeadragon.TileSource} otherSource
+     * @returns {Boolean}
+     */
+    equals: function (otherSource) {
+        return false;
+    },
+
     /**
      * Responsible for parsing and configuring the
      * image metadata pertinent to this TileSources implementation.

src/tmstilesource.js

@@ -131,6 +131,13 @@ $.extend( $.TmsTileSource.prototype, $.TileSource.prototype, /** @lends OpenSead
         var yTiles = this.getNumTiles( level ).y - 1;
 
         return this.tilesUrl + level + "/" + x + "/" + (yTiles - y) + ".png";
+    },
+
+    /**
+     * Equality comparator
+     */
+    equals: function (otherSource) {
+        return this.tilesUrl === otherSource.tilesUrl;
     }
 });
 

src/viewer.js

@@ -1452,7 +1452,7 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
      *      A set of headers to include when making tile AJAX requests.
      *      Note that these headers will be merged over any headers specified in {@link OpenSeadragon.Options}.
      *      Specifying a falsy value for a header will clear its existing value set at the Viewer level (if any).
-     * @param {Function} [options.success] A function that gets called when the image is
+     * @param {Function} [options.success] A function tadhat gets called when the image is
      * successfully added. It's passed the event object which contains a single property:
      * "item", which is the resulting instance of TiledImage.
      * @param {Function} [options.error] A function that gets called if the image is
@@ -1575,11 +1575,15 @@ $.extend( $.Viewer.prototype, $.EventSource.prototype, $.ControlDock.prototype,
                 _this._loadQueue.splice(0, 1);
 
                 if (queueItem.options.replace) {
-                    var newIndex = _this.world.getIndexOfItem(queueItem.options.replaceItem);
+                    const replaced = queueItem.options.replaceItem;
+                    const newIndex = _this.world.getIndexOfItem(replaced);
                     if (newIndex !== -1) {
                         queueItem.options.index = newIndex;
                     }
-                    _this.world.removeItem(queueItem.options.replaceItem);
+                    if (!replaced._zombieCache && replaced.source.equals(queueItem.tileSource)) {
+                        replaced.allowZombieCache(true);
+                    }
+                    _this.world.removeItem(replaced);
                 }
 
                 tiledImage = new $.TiledImage({

src/zoomifytilesource.js

@@ -143,6 +143,13 @@
             result = Math.floor(num / 256);
             return this.tilesUrl + 'TileGroup' + result + '/' + level + '-' + x + '-' + y + '.' + this.fileFormat;
 
+        },
+
+        /**
+         * Equality comparator
+         */
+        equals: function (otherSource) {
+            return this.tilesUrl === otherSource.tilesUrl;
         }
     });
 

test/modules/tilecache.js

@@ -278,21 +278,13 @@
             viewer.world.removeHandler('add-item', openHandler);
             viewer.world.addHandler('add-item', reopenHandler);
 
-            const oldCacheSize = event.item._tileCache._cachesLoadedCount +
-                event.item._tileCache._zombiesLoadedCount;
-
             waitFor(() => {
                 if (tilesFinished === jobCounter && event.item._fullyLoaded) {
                     coverage = $.extend(true, {}, event.item.coverage);
                     viewer.addTiledImage({
                         tileSource: '/test/data/testpattern.dzi',
                         index: 0,
-                        replace: true,
-                        success: e => {
-                            test.equal(oldCacheSize, e.item._tileCache._cachesLoadedCount +
-                                e.item._tileCache._zombiesLoadedCount,
-                                "Image replace should erase no cache with zombies.");
-                        }
+                        replace: true
                     });
                     return true;
                 }