proper gc rooting

2026-02-21 13:12:34 -06:00
parent a1fa8020c5
commit ad7ee40fe0
5 changed files with 40 additions and 25 deletions
--- 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
--- 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);
--- 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);
 )
--- 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
  }
--- 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);