From d41c649a5c28d8454f39282cbdb5a5e53ef122da Mon Sep 17 00:00:00 2001
From: Yotam Mann <yotammann@gmail.com>
Date: Sun, 21 May 2017 19:12:14 -0700
Subject: [PATCH] Buffer onload and onprogress only rely on downloadQueue and
 not currentDownloads count

---
 Tone/core/Buffer.js | 44 ++++++++++++++++++++++++--------------------
 1 file changed, 24 insertions(+), 20 deletions(-)

diff --git a/Tone/core/Buffer.js b/Tone/core/Buffer.js
index 9ab8ea0d..2382d43a 100644
--- a/Tone/core/Buffer.js
+++ b/Tone/core/Buffer.js
@@ -162,8 +162,7 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 		Tone.prototype.dispose.call(this);
 		this._buffer = null;
 		if (this._xhr){
-			Tone.Buffer._currentDownloads--;
-			Math.max(Tone.Buffer._currentDownloads, 0);
+			Tone.Buffer._removeFromDownloadQueue(this._xhr);
 			this._xhr.abort();
 			this._xhr = null;
 		}
@@ -377,13 +376,6 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 	 */
 	Tone.Buffer._downloadQueue = [];
 
-	/**
-	 *  the total number of downloads
-	 *  @type {Number}
-	 *  @private
-	 */
-	Tone.Buffer._currentDownloads = 0;
-
 	/**
 	 *  A path which is prefixed before every url.
 	 *  @type  {String}
@@ -401,6 +393,17 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 		return (new Tone.Buffer()).fromArray(array);
 	};
 
+	/**
+	 * Remove an xhr request from the download queue
+	 * @private
+	 */
+	Tone.Buffer._removeFromDownloadQueue = function(request){
+		var index = Tone.Buffer._downloadQueue.indexOf(request);
+		if (index !== -1){
+			Tone.Buffer._downloadQueue.splice(index, 1);
+		}
+	};
+
 	/**
 	 *  Loads a url using XMLHttpRequest.
 	 *  @param {String} url
@@ -414,6 +417,7 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 		onload = onload || Tone.noOp;
 
 		function onError(e){
+			Tone.Buffer._removeFromDownloadQueue(request);
 			if (onerror){
 				onerror(e);
 				Tone.Buffer.emit("error", e);
@@ -424,11 +428,13 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 
 		function onProgress(){
 			//calculate the progress
-			var totalProgress = 0;
-			for (var i = 0; i < Tone.Buffer._downloadQueue.length; i++){
-				totalProgress += Tone.Buffer._downloadQueue[i].progress;
+			if (Tone.Buffer._downloadQueue.length > 0){
+				var totalProgress = 0;
+				for (var i = 0; i < Tone.Buffer._downloadQueue.length; i++){
+					totalProgress += Tone.Buffer._downloadQueue[i].progress;
+				}
+				Tone.Buffer.emit("progress", totalProgress / Tone.Buffer._downloadQueue.length);
 			}
-			Tone.Buffer.emit("progress", totalProgress / Tone.Buffer._downloadQueue.length);
 		}
 
 		var request = new XMLHttpRequest();
@@ -437,10 +443,10 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 		//start out as 0
 		request.progress = 0;
 
-		Tone.Buffer._currentDownloads++;
 		Tone.Buffer._downloadQueue.push(request);
 
 		request.addEventListener("load", function(){
+
 			if (request.status === 200){
 				Tone.context.decodeAudioData(request.response, function(buff) {
 
@@ -448,15 +454,13 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 					onProgress();
 					onload(buff);
 
-					Tone.Buffer._currentDownloads--;
-					if (Tone.Buffer._currentDownloads === 0){
-						// clear the downloads
-						Tone.Buffer._downloadQueue = [];
+					Tone.Buffer._removeFromDownloadQueue(request);
+					if (Tone.Buffer._downloadQueue.length === 0){
 						//emit the event at the end
 						Tone.Buffer.emit("load");
 					}
-
 				}, function(){
+					Tone.Buffer._removeFromDownloadQueue(request);
 					onError("Tone.Buffer: could not decode audio data: "+url);
 				});
 			} else {
@@ -485,9 +489,9 @@ define(["Tone/core/Tone", "Tone/core/Emitter", "Tone/type/Type"], function(Tone)
 	 */
 	Tone.Buffer.cancelDownloads = function(){
 		Tone.Buffer._downloadQueue.forEach(function(request){
+			Tone.Buffer._removeFromDownloadQueue(request);
 			request.abort();
 		});
-		Tone.Buffer._currentDownloads = 0;
 		return Tone.Buffer;
 	};