From ad7ee40fe0efd87a5abf28fe2be883d526dcc382 Mon Sep 17 00:00:00 2001
From: John Alanbrook <john@pockle.world>
Date: Sat, 21 Feb 2026 13:12:34 -0600
Subject: [PATCH] proper gc rooting

---
 dsp.c        |  3 +--
 flac.c       | 15 ++++++++++-----
 mp3.c        | 16 +++++++++++-----
 soundwave.cm | 16 ++++++++--------
 wav.c        | 15 ++++++++++-----
 5 files changed, 40 insertions(+), 25 deletions(-)

diff --git a/dsp.c b/dsp.c
index 8097978..d2ada44 100644
--- a/dsp.c
+++ b/dsp.c
@@ -17,9 +17,8 @@ JSC_CCALL(dsp_mix_blobs,
   if (!JS_IsArray(vols_arr)) return JS_ThrowTypeError(js, "volumes must be an array");
 
   int len = 0;
-  JSValue len_val = JS_GetPropertyStr(js, blobs_arr, "length");
+  JSValue len_val = JS_CellLength(js, blobs_arr);
   JS_ToInt32(js, &len, len_val);
-  JS_FreeValue(js, len_val);
 
   if (len == 0) {
     // Return empty stoned blob
diff --git a/flac.c b/flac.c
index 6116417..c94ef05 100644
--- a/flac.c
+++ b/flac.c
@@ -28,10 +28,12 @@ static JSValue flac_make_info(JSContext *js, drflac *flac)
   JS_SetPropertyStr(js, obj.val, "channels", JS_NewInt32(js, flac->channels));
   JS_SetPropertyStr(js, obj.val, "sample_rate", JS_NewInt32(js, flac->sampleRate));
   JS_SetPropertyStr(js, obj.val, "bits_per_sample", JS_NewInt32(js, flac->bitsPerSample));
-  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", JS_NewFloat64(js, (double)flac->totalPCMFrameCount));
+  JSValue pcm_count = JS_NewFloat64(js, (double)flac->totalPCMFrameCount);
+  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", pcm_count);
   JS_SetPropertyStr(js, obj.val, "decoded_bytes_per_frame",
     JS_NewInt32(js, (int)((size_t)flac->channels * sizeof(drflac_int32))));
-  JS_SetPropertyStr(js, obj.val, "format", JS_NewString(js, "s32"));
+  JSValue fmt = JS_NewString(js, "s32");
+  JS_SetPropertyStr(js, obj.val, "format", fmt);
   JS_RETURN(obj.val);
 }
 
@@ -94,11 +96,14 @@ JSC_CCALL(flac_decode,
   JS_FRAME(js);
   JS_ROOT(result, flac_make_info(js, flac));
 
-  // Update format info
-  JS_SetPropertyStr(js, result.val, "format", JS_NewString(js, "f32"));
+  // Update format info — evaluate allocating calls in separate statements
+  // (C argument evaluation order is unspecified; GC can invalidate .val)
+  JSValue fmt = JS_NewString(js, "f32");
+  JS_SetPropertyStr(js, result.val, "format", fmt);
   JS_SetPropertyStr(js, result.val, "decoded_bytes_per_frame", JS_NewInt32(js, (int)bytes_per_frame));
 
-  JS_SetPropertyStr(js, result.val, "pcm", js_new_blob_stoned_copy(js, pcm, bytes_read));
+  JSValue pcm_blob = js_new_blob_stoned_copy(js, pcm, bytes_read);
+  JS_SetPropertyStr(js, result.val, "pcm", pcm_blob);
   free(pcm);
   drflac_close(flac);
   JS_RETURN(result.val);
diff --git a/mp3.c b/mp3.c
index dea55e7..963cfda 100644
--- a/mp3.c
+++ b/mp3.c
@@ -14,10 +14,12 @@ static JSValue mp3_make_info(JSContext *js, drmp3_uint32 channels, drmp3_uint32
   JS_SetPropertyStr(js, obj.val, "bits_per_sample", JS_NewInt32(js, 16));
 
   double total_frames = frames == DRMP3_UINT64_MAX ? -1.0 : (double)frames;
-  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", JS_NewFloat64(js, total_frames));
+  JSValue pcm_count = JS_NewFloat64(js, total_frames);
+  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", pcm_count);
   JS_SetPropertyStr(js, obj.val, "decoded_bytes_per_frame",
     JS_NewInt32(js, (int)((size_t)channels * sizeof(drmp3_int16))));
-  JS_SetPropertyStr(js, obj.val, "format", JS_NewString(js, "s16"));
+  JSValue fmt = JS_NewString(js, "s16");
+  JS_SetPropertyStr(js, obj.val, "format", fmt);
   JS_RETURN(obj.val);
 }
 
@@ -85,11 +87,15 @@ JSC_CCALL(mp3_decode,
   JS_FRAME(js);
   JS_ROOT(result, mp3_make_info(js, config.channels, config.sampleRate, frames));
 
-  // Update format info
-  JS_SetPropertyStr(js, result.val, "format", JS_NewString(js, "f32"));
+  // Update format info — evaluate allocating calls before reading .val
+  // (C argument evaluation order is unspecified; GC during allocation
+  // can move the rooted object, invalidating an already-read .val)
+  JSValue fmt = JS_NewString(js, "f32");
+  JS_SetPropertyStr(js, result.val, "format", fmt);
   JS_SetPropertyStr(js, result.val, "decoded_bytes_per_frame", JS_NewInt32(js, (int)bytes_per_frame));
 
-  JS_SetPropertyStr(js, result.val, "pcm", js_new_blob_stoned_copy(js, pcm, total_bytes));
+  JSValue pcm_blob = js_new_blob_stoned_copy(js, pcm, total_bytes);
+  JS_SetPropertyStr(js, result.val, "pcm", pcm_blob);
   drmp3_free(pcm, NULL);
   JS_RETURN(result.val);
 )
diff --git a/soundwave.cm b/soundwave.cm
index 312eb60..7613162 100644
--- a/soundwave.cm
+++ b/soundwave.cm
@@ -139,16 +139,16 @@ soundwave.create = function(opts) {
   // Pull a chunk of audio from a voice, handling looping
   function pull_voice_chunk(voice, frames) {
     if (voice.stopped) return null
-    
+
     var source = voice.source
     var total_frames = source.frames
     var pos = voice.pos
     var bytes_per_frame = player.channels * BYTES_PER_SAMPLE
     var bits_per_frame = bytes_per_frame * 8
-    
+
     var out = Blob()
     var frames_written = 0
-    
+
     var frames_available = null
     var frames_needed = null
     var frames_to_read = null
@@ -172,13 +172,13 @@ soundwave.create = function(opts) {
       end_bit = (pos + frames_to_read) * bits_per_frame
       chunk = source.pcm.read_blob(start_bit, end_bit)
       out.write_blob(chunk)
-      
+
       pos += frames_to_read
       frames_written += frames_to_read
     }
-    
+
     voice.pos = pos
-    
+
     // Pad with silence if needed
     var silence_frames = null
     var silence = null
@@ -187,7 +187,7 @@ soundwave.create = function(opts) {
       silence = dsp.silence(silence_frames, player.channels)
       out.write_blob(silence)
     }
-    
+
     stone(out)
     return out
   }
@@ -259,7 +259,7 @@ soundwave.create = function(opts) {
     } else {
       mixed = dsp.mix_blobs(blobs, vols)
     }
-    
+
     player.cleanup()
     return mixed
   }
diff --git a/wav.c b/wav.c
index fdd4f73..d8af4ef 100644
--- a/wav.c
+++ b/wav.c
@@ -29,7 +29,8 @@ static JSValue wav_make_info(JSContext *js, drwav *wav)
   JS_SetPropertyStr(js, obj.val, "sample_rate", JS_NewInt32(js, wav->sampleRate));
   JS_SetPropertyStr(js, obj.val, "bits_per_sample", JS_NewInt32(js, wav->bitsPerSample));
   JS_SetPropertyStr(js, obj.val, "format_tag", JS_NewInt32(js, wav->translatedFormatTag));
-  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", JS_NewFloat64(js, (double)wav->totalPCMFrameCount));
+  JSValue pcm_count = JS_NewFloat64(js, (double)wav->totalPCMFrameCount);
+  JS_SetPropertyStr(js, obj.val, "total_pcm_frames", pcm_count);
   JS_SetPropertyStr(js, obj.val, "bytes_per_frame", JS_NewInt32(js, (int)drwav_get_bytes_per_pcm_frame(wav)));
   JS_RETURN(obj.val);
 }
@@ -94,15 +95,19 @@ JSC_CCALL(wav_decode,
 
   JS_FRAME(js);
   JS_ROOT(result, wav_make_info(js, &wav));
-  // Update format info to reflect f32
-  JS_SetPropertyStr(js, result.val, "format", JS_NewString(js, "f32"));
+  // Update format info — evaluate allocating calls in separate statements
+  // (C argument evaluation order is unspecified; GC can invalidate .val)
+  JSValue fmt = JS_NewString(js, "f32");
+  JS_SetPropertyStr(js, result.val, "format", fmt);
   JS_SetPropertyStr(js, result.val, "bytes_per_frame", JS_NewInt32(js, (int)bytes_per_frame));
 
   if (pcm_bytes > 0) {
-    JS_SetPropertyStr(js, result.val, "pcm", js_new_blob_stoned_copy(js, pcm, bytes_read));
+    JSValue pcm_blob = js_new_blob_stoned_copy(js, pcm, bytes_read);
+    JS_SetPropertyStr(js, result.val, "pcm", pcm_blob);
     free(pcm);
   } else {
-    JS_SetPropertyStr(js, result.val, "pcm", js_new_blob_stoned_copy(js, NULL, 0));
+    JSValue pcm_blob = js_new_blob_stoned_copy(js, NULL, 0);
+    JS_SetPropertyStr(js, result.val, "pcm", pcm_blob);
   }
 
   drwav_uninit(&wav);