From a5eab8264cdf25f830a11a77f92960a34bb35e45 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kasper=20Isager=20Dalsgar=C3=B0?= <kasperisager@hey.com>
Date: Fri, 5 Apr 2024 12:05:54 +0200
Subject: [PATCH] `memcpy()` thread source to avoid race condition

---
 src/runtime.c |  3 +++
 src/thread.c  | 33 +++++++++++++++++++++++++--------
 src/types.h   |  2 ++
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/src/runtime.c b/src/runtime.c
index ceb8caf..09a3e59 100644
--- a/src/runtime.c
+++ b/src/runtime.c
@@ -1118,6 +1118,9 @@ bare_runtime_run (bare_runtime_t *runtime, const char *filename, bare_source_t s
     err = js_create_external_arraybuffer(env, source.buffer.base, source.buffer.len, NULL, NULL, &args[1]);
     assert(err == 0);
     break;
+
+  case bare_source_arraybuffer:
+    args[1] = source.arraybuffer;
   }
   }
 
diff --git a/src/thread.c b/src/thread.c
index f1a8624..6bf8c80 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -14,10 +14,10 @@
 #include "types.h"
 
 static void
-bare_thread_entry (void *data) {
+bare_thread_entry (void *opaque) {
   int err;
 
-  bare_thread_t *thread = (bare_thread_t *) data;
+  bare_thread_t *thread = (bare_thread_t *) opaque;
 
   bare_runtime_t *runtime = thread->runtime;
 
@@ -38,19 +38,36 @@ bare_thread_entry (void *data) {
   err = js_open_handle_scope(env, &scope);
   assert(err == 0);
 
-  bare_source_t thread_source = thread->source;
+  bare_source_t source;
 
-  js_value_t *thread_data;
+  switch (thread->source.type) {
+  case bare_source_none:
+  case bare_source_arraybuffer:
+    source.type = bare_source_none;
+    break;
+
+  case bare_source_buffer:
+    source.type = bare_source_arraybuffer;
+
+    void *data;
+    err = js_create_arraybuffer(env, thread->source.buffer.len, &data, &source.arraybuffer);
+    assert(err == 0);
+
+    memcpy(data, thread->source.buffer.base, thread->source.buffer.len);
+    break;
+  }
+
+  js_value_t *data;
 
   switch (thread->data.type) {
   case bare_data_none:
   default:
-    err = js_get_null(runtime->env, &thread_data);
+    err = js_get_null(runtime->env, &data);
     assert(err == 0);
     break;
 
   case bare_data_sharedarraybuffer: {
-    err = js_create_sharedarraybuffer_with_backing_store(env, thread->data.backing_store, NULL, NULL, &thread_data);
+    err = js_create_sharedarraybuffer_with_backing_store(env, thread->data.backing_store, NULL, NULL, &data);
     assert(err == 0);
 
     err = js_release_arraybuffer_backing_store(env, thread->data.backing_store);
@@ -71,14 +88,14 @@ bare_thread_entry (void *data) {
   err = js_get_global(env, &global);
   assert(err == 0);
 
-  js_call_function(env, global, fn, 1, (js_value_t *[]){thread_data}, NULL);
+  js_call_function(env, global, fn, 1, (js_value_t *[]){data}, NULL);
 
   err = js_close_handle_scope(env, scope);
   assert(err == 0);
 
   uv_sem_post(&thread->lock);
 
-  bare_runtime_run(runtime, thread->filename, thread_source);
+  bare_runtime_run(runtime, thread->filename, thread->source);
 
   free(thread->filename);
 
diff --git a/src/types.h b/src/types.h
index 2449af4..0e420cb 100644
--- a/src/types.h
+++ b/src/types.h
@@ -57,10 +57,12 @@ struct bare_source_s {
   enum {
     bare_source_none,
     bare_source_buffer,
+    bare_source_arraybuffer,
   } type;
 
   union {
     uv_buf_t buffer;
+    js_value_t *arraybuffer;
   };
 };