onceEnded mechanism to clean audioNode.onended callbacks

packages/soundfonts/fontloader.mjs

@@ -6,6 +6,7 @@ import {
   getADSRValues,
   getPitchEnvelope,
   getVibratoOscillator,
+  onceEnded,
 } from '@strudel/webaudio';
 import gm from './gm.mjs';
 
@@ -170,12 +171,12 @@ export function registerSoundfonts() {
 
         bufferSource.stop(envEnd);
         const stop = (releaseTime) => {};
-        bufferSource.onended = () => {
+        onceEnded(bufferSource, () => {
           bufferSource.disconnect();
           vibratoOscillator?.stop();
           node.disconnect();
           onended();
-        };
+        });
         return { node, stop };
       },
       { type: 'soundfont', prebake: true, fonts },

packages/superdough/helpers.mjs

@@ -349,20 +349,11 @@ export function webAudioTimeout(audioContext, onComplete, startTime, stopTime) {
   constantNode.connect(zeroGain);
 
   // Schedule the `onComplete` callback to occur at `stopTime`
-  constantNode.onended = () => {
+  onceEnded(constantNode, () => {
-    // Ensure garbage collection
+    releaseAudioNode(zeroGain);
-    try {
+    releaseAudioNode(constantNode);
-      zeroGain.disconnect();
-    } catch {
-      // pass
-    }
-    try {
-      constantNode.disconnect();
-    } catch {
-      // pass
-    }
     onComplete();
-  };
+  });
   constantNode.start(startTime);
   constantNode.stop(stopTime);
   return constantNode;
@@ -554,6 +545,17 @@ export const getFrequencyFromValue = (value, defaultNote = 36) => {
   return Number(freq);
 };
 
+// This helper should be used instead of the `node.onended = callback` pattern
+// It adds a mechanism to help minimize gc retention
+export const onceEnded = (node, callback) => {
+  let onended = callback;
+  node.onended = function cleanup() {
+    onended && onended();
+    onended = null;
+    this.onended = null;
+  };
+};
+
 export const releaseAudioNode = (node) => {
   if (node == null) return;
 
@@ -565,16 +567,24 @@ export const releaseAudioNode = (node) => {
   // https://developer.mozilla.org/en-US/docs/Web/API/AudioNode/disconnect
   node.disconnect();
 
-  // make sure all AudioScheduledSourceNode is in a stopped state
+  // make sure all AudioScheduledSourceNodes are in a stopped state
   // https://developer.mozilla.org/en-US/docs/Web/API/AudioScheduledSourceNode
   if (node instanceof AudioScheduledSourceNode) {
+    if (node.onended && node.onended.name !== 'cleanup') {
+      logger(
+        `[superdough] Deprecation warning: it seems your code path is setting 'node.onended = callback' instead of using the onceEnded helper`,
+      );
+    }
     try {
       node.stop();
     } catch (e) {
-      if (e instanceof DOMException && e.name === 'InvalidStateError') {
+      // At the stage, `start` was not called on the node
-        node.start(node.context.currentTime + 5); // will never happen
+      // but an `onended` callback releasing resources may exist
-        node.stop();
+      // and we want it to fire :
-      }
+      // - we force a start/stop cycle so that `onended` gets called
+      // - we `lock` the node so that no-one can start it
+      node.start(node.context.currentTime + 5); // will never happen
+      node.stop();
     }
   }
 

packages/superdough/sampler.mjs

@@ -1,7 +1,14 @@
 import { getBaseURL, getCommonSampleInfo } from './util.mjs';
 import { registerSound, registerWaveTable } from './index.mjs';
 import { getAudioContext } from './audioContext.mjs';
-import { getADSRValues, getParamADSR, getPitchEnvelope, getVibratoOscillator, releaseAudioNode } from './helpers.mjs';
+import {
+  getADSRValues,
+  getParamADSR,
+  getPitchEnvelope,
+  getVibratoOscillator,
+  onceEnded,
+  releaseAudioNode,
+} from './helpers.mjs';
 import { logger } from './logger.mjs';
 
 const bufferCache = {}; // string: Promise<ArrayBuffer>
@@ -321,13 +328,13 @@ export async function onTriggerSample(t, value, onended, bank, resolveUrl) {
 
   const out = ac.createGain(); // we need a separate gain for the cutgroups because firefox...
   node.connect(out);
-  bufferSource.onended = function () {
+  onceEnded(bufferSource, function () {
     bufferSource.disconnect();
     vibratoOscillator?.stop();
     node.disconnect();
     out.disconnect();
     onended();
-  };
+  });
   let envEnd = holdEnd + release + 0.01;
   bufferSource.stop(envEnd);
   const stop = (endTime) => {

packages/superdough/zzfx.mjs

@@ -3,6 +3,7 @@ import { midiToFreq, noteToMidi } from './util.mjs';
 import { registerSound } from './superdough.mjs';
 import { getAudioContext } from './audioContext.mjs';
 import { buildSamples } from './zzfx_fork.mjs';
+import { onceEnded, releaseAudioNode } from './helpers.mjs';
 
 export const getZZFX = (value, t) => {
   let {
@@ -83,10 +84,10 @@ export function registerZZFXSounds() {
       wave,
       (t, value, onended) => {
         const { node: o } = getZZFX({ s: wave, ...value }, t);
-        o.onended = () => {
+        onceEnded(o, () => {
-          o.disconnect();
+          releaseAudioNode(o);
           onended();
-        };
+        });
         return {
           node: o,
           stop: () => {},