From da201d9ea5e00f7fd2aefc3222759f3c253c1882 Mon Sep 17 00:00:00 2001
From: Aapo Alasuutari <aapo.alasuutari@gmail.com>
Date: Sun, 5 Mar 2023 10:01:23 +0200
Subject: [PATCH] feat(ext/ffi): Make External pointers keep reference to V8
 buffer (#17955)

---
 ext/ffi/00_ffi.js       | 8 +++++++-
 test_ffi/tests/bench.js | 6 ------
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/ext/ffi/00_ffi.js b/ext/ffi/00_ffi.js
index d107e89fa9..a63a027e80 100644
--- a/ext/ffi/00_ffi.js
+++ b/ext/ffi/00_ffi.js
@@ -26,6 +26,7 @@ const {
   SafeMap,
   SafeArrayIterator,
   SymbolFor,
+  WeakMap,
 } = primordials;
 
 const promiseIdSymbol = SymbolFor("Deno.core.internalPromiseId");
@@ -179,6 +180,7 @@ class UnsafePointerView {
 
 const OUT_BUFFER = new Uint32Array(2);
 const OUT_BUFFER_64 = new BigInt64Array(OUT_BUFFER.buffer);
+const POINTER_TO_BUFFER_WEAK_MAP = new WeakMap();
 class UnsafePointer {
   static create(value) {
     return ops.op_ffi_ptr_create(value);
@@ -195,7 +197,11 @@ class UnsafePointer {
     if (ObjectPrototypeIsPrototypeOf(UnsafeCallbackPrototype, value)) {
       return value.pointer;
     }
-    return ops.op_ffi_ptr_of(value);
+    const pointer = ops.op_ffi_ptr_of(value);
+    if (pointer) {
+      POINTER_TO_BUFFER_WEAK_MAP.set(pointer, value);
+    }
+    return pointer;
   }
 
   static offset(value, offset) {
diff --git a/test_ffi/tests/bench.js b/test_ffi/tests/bench.js
index b70b41e8f5..a3983fb2ba 100644
--- a/test_ffi/tests/bench.js
+++ b/test_ffi/tests/bench.js
@@ -354,8 +354,6 @@ Deno.bench("nop_f64()", () => {
 
 const { nop_buffer } = dylib.symbols;
 const buffer = new Uint8Array(8).fill(5);
-// Make sure the buffer does not get collected
-globalThis.buffer = buffer;
 Deno.bench("nop_buffer()", () => {
   nop_buffer(buffer);
 });
@@ -565,8 +563,6 @@ Deno.bench("return_buffer_nonblocking()", async () => {
 
 const { nop_many_parameters } = dylib.symbols;
 const buffer2 = new Uint8Array(8).fill(25);
-// Make sure the buffer does not get collected
-globalThis.buffer2 = buffer2;
 Deno.bench("nop_many_parameters()", () => {
   nop_many_parameters(
     135,
@@ -635,8 +631,6 @@ Deno.bench("Deno.UnsafePointer.of", () => {
 });
 
 const cstringBuffer = new TextEncoder().encode("Best believe it!\0");
-// Make sure the buffer does not get collected
-globalThis.cstringBuffer = cstringBuffer;
 const cstringPointerView = new Deno.UnsafePointerView(
   Deno.UnsafePointer.of(cstringBuffer),
 );