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src: add internal isArrayBufferDetached #45568

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merged 1 commit into from Nov 27, 2022
Merged

src: add internal isArrayBufferDetached #45568

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11 changes: 11 additions & 0 deletions lib/internal/util.js
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@@ -1,6 +1,7 @@
'use strict';

const {
ArrayBufferPrototypeGetByteLength,
ArrayFrom,
ArrayIsArray,
ArrayPrototypePush,
Expand Down Expand Up @@ -42,6 +43,7 @@ const {
} = require('internal/errors');
const { signals } = internalBinding('constants').os;
const {
isArrayBufferDetached: _isArrayBufferDetached,
privateSymbols: {
arrow_message_private_symbol,
decorated_private_symbol,
Expand Down Expand Up @@ -560,6 +562,14 @@ function SideEffectFreeRegExpPrototypeExec(regex, string) {
return FunctionPrototypeCall(RegExpFromAnotherRealm.prototype.exec, regex, string);
}

function isArrayBufferDetached(value) {
if (ArrayBufferPrototypeGetByteLength(value) === 0) {
return _isArrayBufferDetached(value);
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Crossing the JS-C++ boundary is gonna be slower than the current implementation although I'm not sure if this call in the zero length case is gonna be the primary bottleneck for any user code.

Did you consider implementing @jasnell's suggestion in #45512 (comment)? Seems like that approach would solve this problem without adding any performance overhead in any case.

One thing we might be able to do is add a hidden symbol to ArrayBuffer instances when we detach them in c++ land. Then we can have an isDetached check in js that checks the length and the presence of that symbol.

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@anonrig anonrig Nov 23, 2022 •
edited

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IMHO, that is the perfect solution for performance, but I believe it's too hacky to maintain in the long term. I can't think of a good/maintainable way to enforce attaching the hidden symbol as a rule.

If it's the consensus @jasnell thinks is the best way, I'll be happy to implement it regardless.

}

return false;
Comment on lines +566 to +570
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Nit: the flow might look semantically better like this

Suggested change
if (ArrayBufferPrototypeGetByteLength(value) === 0) {
return _isArrayBufferDetached(value);
}
return false;
if (ArrayBufferPrototypeGetByteLength(value) !== 0) {
return false;
}
return _isArrayBufferDetached(value);

}

module.exports = {
assertCrypto,
cachedResult,
Expand All @@ -577,6 +587,7 @@ module.exports = {
getInternalGlobal,
getSystemErrorMap,
getSystemErrorName,
isArrayBufferDetached,
isError,
isInsideNodeModules,
join,
Expand Down
6 changes: 3 additions & 3 deletions lib/internal/webstreams/readablestream.js
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Expand Up @@ -51,6 +51,7 @@ const {
const {
createDeferredPromise,
customInspectSymbol: kInspect,
isArrayBufferDetached,
kEmptyObject,
kEnumerableProperty,
} = require('internal/util');
Expand Down Expand Up @@ -104,7 +105,6 @@ const {
extractHighWaterMark,
extractSizeAlgorithm,
lazyTransfer,
isDetachedBuffer,
isViewedArrayBufferDetached,
isBrandCheck,
resetQueue,
Expand Down Expand Up @@ -669,7 +669,7 @@ class ReadableStreamBYOBRequest {
const viewBuffer = ArrayBufferViewGetBuffer(view);
const viewBufferByteLength = ArrayBufferPrototypeGetByteLength(viewBuffer);

if (isDetachedBuffer(viewBuffer)) {
if (isArrayBufferDetached(viewBuffer)) {
throw new ERR_INVALID_STATE.TypeError('Viewed ArrayBuffer is detached');
}

Expand Down Expand Up @@ -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',
);
Expand Down
18 changes: 2 additions & 16 deletions lib/internal/webstreams/util.js
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@@ -1,7 +1,6 @@
'use strict';

const {
ArrayBufferPrototypeGetByteLength,
ArrayBufferPrototypeSlice,
ArrayPrototypePush,
ArrayPrototypeShift,
Expand Down Expand Up @@ -45,6 +44,7 @@ const {
} = internalBinding('util');

const assert = require('internal/assert');
const { isArrayBufferDetached } = require('internal/util');

const kState = Symbol('kState');
const kType = Symbol('kType');
Expand Down Expand Up @@ -135,23 +135,10 @@ function transferArrayBuffer(buffer) {
return res;
}

function isDetachedBuffer(buffer) {
if (ArrayBufferPrototypeGetByteLength(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))
);
}

Expand Down Expand Up @@ -251,7 +238,6 @@ module.exports = {
extractSizeAlgorithm,
lazyTransfer,
isBrandCheck,
isDetachedBuffer,
isPromisePending,
isViewedArrayBufferDetached,
peekQueueValue,
Expand Down
12 changes: 12 additions & 0 deletions src/node_util.cc
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Expand Up @@ -137,6 +137,15 @@ static void GetProxyDetails(const FunctionCallbackInfo<Value>& args) {
}
}

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);
}

static void PreviewEntries(const FunctionCallbackInfo<Value>& args) {
if (!args[0]->IsObject())
return;
Expand Down Expand Up @@ -342,6 +351,7 @@ static void ToUSVString(const FunctionCallbackInfo<Value>& args) {
void RegisterExternalReferences(ExternalReferenceRegistry* registry) {
registry->Register(GetPromiseDetails);
registry->Register(GetProxyDetails);
registry->Register(IsArrayBufferDetached);
registry->Register(PreviewEntries);
registry->Register(GetOwnNonIndexProperties);
registry->Register(GetConstructorName);
Expand Down Expand Up @@ -403,6 +413,8 @@ void Initialize(Local<Object> target,
SetMethodNoSideEffect(
context, target, "getPromiseDetails", GetPromiseDetails);
SetMethodNoSideEffect(context, target, "getProxyDetails", GetProxyDetails);
SetMethodNoSideEffect(
context, target, "isArrayBufferDetached", IsArrayBufferDetached);
SetMethodNoSideEffect(context, target, "previewEntries", PreviewEntries);
SetMethodNoSideEffect(
context, target, "getOwnNonIndexProperties", GetOwnNonIndexProperties);
Expand Down