removing source when sample has finished

prevents error where the BufferSource.stop is attempted after the source has already finished

Tone/instrument/Sampler.js

@@ -137,10 +137,15 @@ define(["Tone/core/Tone", "Tone/instrument/Instrument", "Tone/core/Buffers", "To
 				if (!Tone.isArray(this._activeSources[midi])){
 					this._activeSources[midi] = [];
 				}
-				this._activeSources[midi].push({
-					note : midi,
-					source : source
-				});
+				this._activeSources[midi].push(source);
+
+				//remove it when it's done
+				source.onended = function(){
+					var index = this._activeSources[midi].indexOf(source);
+					if (index !== -1){
+						this._activeSources[midi].splice(index, 1);
+					}
+				}.bind(this);
 			}
 		}
 		return this;
@@ -160,7 +165,7 @@ define(["Tone/core/Tone", "Tone/instrument/Instrument", "Tone/core/Buffers", "To
 			var midi = Tone.Frequency(notes[i]).toMidi();
 			// find the note
 			if (this._activeSources[midi] && this._activeSources[midi].length){
-				var source = this._activeSources[midi].shift().source;
+				var source = this._activeSources[midi].shift();
 				time = this.toSeconds(time);
 				source.stop(time);
 			}
@@ -179,8 +184,8 @@ define(["Tone/core/Tone", "Tone/instrument/Instrument", "Tone/core/Buffers", "To
 		for (var note in this._activeSources){
 			var sources = this._activeSources[note];
 			while (sources.length){
-				var source = sources.shift().source;
-				source.stop(time + this.release, this.release);
+				var source = sources.shift();
+				source.stop(time);
 			}
 		}
 		return this;
@@ -272,8 +277,8 @@ define(["Tone/core/Tone", "Tone/instrument/Instrument", "Tone/core/Buffers", "To
 		this._buffers.dispose();
 		this._buffers = null;
 		for (var midi in this._activeSources){
-			this._activeSources[midi].forEach(function(event){
-				event.source.dispose();
+			this._activeSources[midi].forEach(function(source){
+				source.dispose();
 			});
 		}
 		this._activeSources = null;

test/instrument/Sampler.js

@@ -1,6 +1,6 @@
 define(["Tone/instrument/Sampler", "helper/Basic", "helper/InstrumentTests",
-	"Tone/core/Buffer", "helper/Offline", "helper/CompareToFile"],
-function(Sampler, Basic, InstrumentTest, Buffer, Offline, CompareToFile){
+	"Tone/core/Buffer", "helper/Offline", "helper/CompareToFile", "helper/Test"],
+function(Sampler, Basic, InstrumentTest, Buffer, Offline, CompareToFile, Test){
 
 	describe("Sampler", function(){
 
@@ -122,6 +122,22 @@ function(Sampler, Basic, InstrumentTest, Buffer, Offline, CompareToFile){
 				});
 			});
 
+			it("can triggerRelease after the buffer has already stopped", function(){
+				return Offline(function(){
+					var sampler = new Sampler({
+						"A4" : A4_buffer
+					}, {
+						release : 0
+					}).toMaster();
+					sampler.triggerAttack("A4", 0);
+					return Test.atTime(A4_buffer.duration + 0.01, function(){
+						sampler.triggerRelease("A4");
+					});
+				}, A4_buffer.duration + 0.1).then(function(buffer){
+					// expect(buffer.getLastSoundTime()).to.be.closeTo(0.2, 0.01);
+				});
+			});
+
 			it("can release multiple notes", function(){
 				return Offline(function(){
 					var sampler = new Sampler({