Fix player faces in sidebar, while still preserving load cache

web/js/minecraft.js

@@ -9,12 +9,44 @@ function createMinecraftHead(player,size,completed,failed) {
 	faceImage.src = dynmap.options.tileUrl + 'faces/' + size + 'x' + size + '/' + player + '.png';
 }
 
+var playerHeads = {};
+
 function getMinecraftHead(player,size,completed) {
-	createMinecraftHead(player, size, completed, function() {
+    var key = player + '.' + size;
-		console.error('Failed to retrieve face of "', player, '" with size "', size, '"!')
+	var head = playerHeads[key];
+	// Synchronous
+	if (!completed) {
+		return (!head || head.working) ? null : head;
+	}
+
+	// Asynchronous
+	if (!head) {
+		playerHeads[key] = { working: true, hooks: [{f:completed}] };
+		createMinecraftHead(player, size, function(head) {
+			hooks = playerHeads[key].hooks;
+			playerHeads[key] = head;
+			var i;
+			for(i=0;i<hooks.length;i++) {
+				hooks[i].f(head);
+			}
+			head.working = false;
+		}, function() {
+
 		});
+	} else if (head.working) {
+		//console.log('Other process working on head of ',player,', will add myself to hooks...');
+		head.hooks[head.hooks.length] = {f:completed};
+	} else {
+		completed(head);
+	}
 }
 
+//function getMinecraftHead(player,size,completed) {
+//	createMinecraftHead(player, size, completed, function() {
+//		console.error('Failed to retrieve face of "', player, '" with size "', size, '"!')
+//	});
+//}
+
 function getMinecraftTime(servertime) {
 	servertime = parseInt(servertime);
 	var day = servertime >= 0 && servertime < 13700;