From eb39f7549f1c4a68a53c0bb6c8370ab7e2265ad0 Mon Sep 17 00:00:00 2001
From: kwigbo <jed@kwigbo.com>
Date: Mon, 11 May 2026 18:52:11 +0000
Subject: [PATCH] Audio: clean up event listeners and buffer view on destroy
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The Audio constructor binds three window-level event listeners
(keydown / click / touchend) to drive startPlayback. They're only
removed when startPlayback() fires; if the Emulator is destroyed
before the user produces a gesture — or if an embedder recreates
the Emulator multiple times before that happens — the listeners
stayed attached to a stale Audio instance forever.

Audio also holds a TypedArray view (this.buffer) into the wasm
heap region returned by _get_audio_buffer_ptr. After Emulator
destroy() calls _emulator_delete + _free, that backing memory is
gone, and any held reference to the buffer view points at freed
memory.

Add Audio.destroy(): removes the gesture listeners and nulls out
the buffer view. Call it from Emulator.destroy() before
_emulator_delete so the cleanup happens while the wasm pointer is
still valid.
---
 docs/simple.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/docs/simple.js b/docs/simple.js
index 968a766..04e8264 100644
--- a/docs/simple.js
+++ b/docs/simple.js
@@ -194,6 +194,7 @@ class Emulator {
     this.cancelAnimationFrame();
     clearInterval(this.rewindIntervalId);
     this.rewind.destroy();
+    this.audio.destroy();
     this.module._emulator_delete(this.e);
     this.module._free(this.romDataPtr);
   }
@@ -658,6 +659,17 @@ class Audio {
     if (!this.started) { return; }
     Audio.ctx.resume();
   }
+
+  destroy() {
+    if (this.boundStartPlayback) {
+      window.removeEventListener('keydown',  this.boundStartPlayback, true);
+      window.removeEventListener('click',    this.boundStartPlayback, true);
+      window.removeEventListener('touchend', this.boundStartPlayback, true);
+      this.boundStartPlayback = null;
+    }
+    this.buffer = null;
+    this.started = false;
+  }
 }
 
 Audio.ctx = new AudioContext;