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fix: use SharedArrayBuffer only when cross-origin isolation is enabled (
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#20831)

* fix: check cross-origin isolation for SharedArrayBuffer

* chore: remove unused a $FlowFixMe comment

* prettier
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koba04 authored Feb 17, 2021
1 parent 0991647 commit 8fa0ccc
Showing 1 changed file with 9 additions and 4 deletions.
13 changes: 9 additions & 4 deletions packages/scheduler/src/SchedulerProfiling.js
Original file line number Diff line number Diff line change
Expand Up @@ -15,13 +15,18 @@ import {NoPriority} from './SchedulerPriorities';
let runIdCounter: number = 0;
let mainThreadIdCounter: number = 0;

const isEnabledSharedArrayBuffer =
// $FlowFixMe Flow doesn't know about SharedArrayBuffer
typeof SharedArrayBuffer === 'function' &&
// We only use SharedArrayBuffer when cross origin isolation is enabled.
typeof window !== 'undefined' &&
window.crossOriginIsolated === true;

const profilingStateSize = 4;
export const sharedProfilingBuffer = enableProfiling
? // $FlowFixMe Flow doesn't know about SharedArrayBuffer
typeof SharedArrayBuffer === 'function'
? isEnabledSharedArrayBuffer
? new SharedArrayBuffer(profilingStateSize * Int32Array.BYTES_PER_ELEMENT)
: // $FlowFixMe Flow doesn't know about ArrayBuffer
typeof ArrayBuffer === 'function'
: typeof ArrayBuffer === 'function'
? new ArrayBuffer(profilingStateSize * Int32Array.BYTES_PER_ELEMENT)
: null // Don't crash the init path on IE9
: null;
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