util: add isArrayBufferDetached method

Author: anonrig

Diff for: doc/api/util.md

@@ -2024,6 +2024,27 @@ util.types.isAnyArrayBuffer(new ArrayBuffer());  // Returns true
 util.types.isAnyArrayBuffer(new SharedArrayBuffer());  // Returns true
 ```
 
+### `util.types.isArrayBufferDetached(value)`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* `value` {any}
+* Returns: {boolean}
+
+Returns `true` if the value is a built-in [`ArrayBuffer`][] and
+is detached. Detached arrays have a byte length of 0, which prevents
+JavaScript from ever accessing underlying backing store.
+
+For example, we can end up with a detached buffer when using a BYOB
+(bring your own buffer) on a ReadableStream.
+
+```js
+util.types.isArrayBufferDetached(null); // Returns false
+util.types.isArrayBufferDetached(new ArrayBuffer()); // Returns false
+```
+
 ### `util.types.isArrayBufferView(value)`
 
 <!-- YAML

Diff for: lib/internal/util/types.js

@@ -2,10 +2,13 @@
 
 const {
   ArrayBufferIsView,
+  ArrayBufferPrototypeGetByteLength,
   ObjectDefineProperties,
   TypedArrayPrototypeGetSymbolToStringTag,
 } = primordials;
 
+const { isArrayBufferDetached: _isArrayBufferDetached, ...internalTypes } = internalBinding('types');
+
 function isTypedArray(value) {
   return TypedArrayPrototypeGetSymbolToStringTag(value) !== undefined;
 }
@@ -54,8 +57,16 @@ function isBigUint64Array(value) {
   return TypedArrayPrototypeGetSymbolToStringTag(value) === 'BigUint64Array';
 }
 
+function isArrayBufferDetached(value) {
+  if (ArrayBufferPrototypeGetByteLength(value) === 0) {
+    return _isArrayBufferDetached(value);
+  }
+  return false;
+}
+
 module.exports = {
-  ...internalBinding('types'),
+  ...internalTypes,
+  isArrayBufferDetached,
   isArrayBufferView: ArrayBufferIsView,
   isTypedArray,
   isUint8Array,

Diff for: lib/internal/webstreams/readablestream.js

@@ -43,6 +43,7 @@ const {
 } = internalBinding('messaging');
 
 const {
+  isArrayBufferDetached,
   isArrayBufferView,
   isDataView,
 } = require('internal/util/types');
@@ -104,7 +105,6 @@ const {
   extractHighWaterMark,
   extractSizeAlgorithm,
   lazyTransfer,
-  isDetachedBuffer,
   isViewedArrayBufferDetached,
   isBrandCheck,
   resetQueue,
@@ -669,7 +669,7 @@ class ReadableStreamBYOBRequest {
     const viewBuffer = ArrayBufferViewGetBuffer(view);
     const viewBufferByteLength = ArrayBufferGetByteLength(viewBuffer);
 
-    if (isDetachedBuffer(viewBuffer)) {
+    if (isArrayBufferDetached(viewBuffer)) {
       throw new ERR_INVALID_STATE.TypeError('Viewed ArrayBuffer is detached');
     }
 
@@ -2643,7 +2643,7 @@ function readableByteStreamControllerEnqueue(controller, chunk) {
   if (pendingPullIntos.length) {
     const firstPendingPullInto = pendingPullIntos[0];
 
-    if (isDetachedBuffer(firstPendingPullInto.buffer)) {
+    if (isArrayBufferDetached(firstPendingPullInto.buffer)) {
       throw new ERR_INVALID_STATE.TypeError(
         'Destination ArrayBuffer is detached',
       );

Diff for: lib/internal/webstreams/util.js

@@ -32,6 +32,7 @@ const {
 } = internalBinding('buffer');
 
 const {
+  isArrayBufferDetached,
   isPromise,
 } = require('internal/util/types');
 
@@ -139,23 +140,10 @@ function transferArrayBuffer(buffer) {
   return res;
 }
 
-function isDetachedBuffer(buffer) {
-  if (ArrayBufferGetByteLength(buffer) === 0) {
-    // TODO(daeyeon): Consider using C++ builtin to improve performance.
-    try {
-      new Uint8Array(buffer);
-    } catch (error) {
-      assert(error.name === 'TypeError');
-      return true;
-    }
-  }
-  return false;
-}
-
 function isViewedArrayBufferDetached(view) {
   return (
     ArrayBufferViewGetByteLength(view) === 0 &&
-    isDetachedBuffer(ArrayBufferViewGetBuffer(view))
+    isArrayBufferDetached(ArrayBufferViewGetBuffer(view))
   );
 }
 
@@ -256,7 +244,6 @@ module.exports = {
   extractSizeAlgorithm,
   lazyTransfer,
   isBrandCheck,
-  isDetachedBuffer,
   isPromisePending,
   isViewedArrayBufferDetached,
   peekQueueValue,

Diff for: src/node_types.cc

@@ -61,6 +61,16 @@ static void IsBoxedPrimitive(const FunctionCallbackInfo<Value>& args) {
     args[0]->IsSymbolObject());
 }
 
+static void IsArrayBufferDetached(const FunctionCallbackInfo<Value>& args) {
+  if (args[0]->IsArrayBuffer()) {
+    auto buffer = args[0].As<v8::ArrayBuffer>();
+    args.GetReturnValue().Set(buffer->WasDetached());
+    return;
+  }
+
+  args.GetReturnValue().Set(false);
+}
+
 void InitializeTypes(Local<Object> target,
                      Local<Value> unused,
                      Local<Context> context,
@@ -71,6 +81,8 @@ void InitializeTypes(Local<Object> target,
 
   SetMethodNoSideEffect(context, target, "isAnyArrayBuffer", IsAnyArrayBuffer);
   SetMethodNoSideEffect(context, target, "isBoxedPrimitive", IsBoxedPrimitive);
+  SetMethodNoSideEffect(
+      context, target, "isArrayBufferDetached", IsArrayBufferDetached);
 }
 
 }  // anonymous namespace
@@ -82,6 +94,7 @@ void RegisterTypesExternalReferences(ExternalReferenceRegistry* registry) {
 
   registry->Register(IsAnyArrayBuffer);
   registry->Register(IsBoxedPrimitive);
+  registry->Register(IsArrayBufferDetached);
 }
 }  // namespace node
 

Diff for: test/parallel/test-util-types.js

@@ -56,7 +56,7 @@ for (const [ value, _method ] of [
   for (const key of Object.keys(types)) {
     if ((types.isArrayBufferView(value) ||
          types.isAnyArrayBuffer(value)) && key.includes('Array') ||
-         key === 'isBoxedPrimitive') {
+         key === 'isBoxedPrimitive' || key === 'isArrayBufferDetached') {
       continue;
     }
 

Diff for: typings/internalBinding/types.d.ts

@@ -5,6 +5,7 @@ declare function InternalBinding(binding: 'types'): {
   isArrayBuffer(value: unknown): value is ArrayBuffer;
   isArgumentsObject(value: unknown): value is ArrayLike<unknown>;
   isBoxedPrimitive(value: unknown): value is (BigInt | Boolean | Number | String | Symbol);
+  isArrayBufferDetached(value: unknown): boolean;
   isDataView(value: unknown): value is DataView;
   isExternal(value: unknown): value is Object;
   isMap(value: unknown): value is Map<unknown, unknown>;