Use a single SharedArrayBuffer

README.md

@@ -111,20 +111,18 @@ export interface GlobalShim {
 
 ### Options
 
-1. `bufferSize` same as env `SYNCKIT_BUFFER_SIZE`
-2. `timeout` same as env `SYNCKIT_TIMEOUT`
-3. `execArgv` same as env `SYNCKIT_EXEC_ARGV`
-4. `tsRunner` same as env `SYNCKIT_TS_RUNNER`
-5. `transferList`: Please refer Node.js [`worker_threads`](https://nodejs.org/api/worker_threads.html#:~:text=Default%3A%20true.-,transferList,-%3CObject%5B%5D%3E%20If) documentation
-6. `globalShims`: Similar like env `SYNCKIT_GLOBAL_SHIMS` but much more flexible which can be a `GlobalShim` `Array`, see `GlobalShim`'s [definition](#types) for more details
+1. `timeout` same as env `SYNCKIT_TIMEOUT`
+2. `execArgv` same as env `SYNCKIT_EXEC_ARGV`
+3. `tsRunner` same as env `SYNCKIT_TS_RUNNER`
+4. `transferList`: Please refer Node.js [`worker_threads`](https://nodejs.org/api/worker_threads.html#:~:text=Default%3A%20true.-,transferList,-%3CObject%5B%5D%3E%20If) documentation
+5. `globalShims`: Similar like env `SYNCKIT_GLOBAL_SHIMS` but much more flexible which can be a `GlobalShim` `Array`, see `GlobalShim`'s [definition](#types) for more details
 
 ### Envs
 
-1. `SYNCKIT_BUFFER_SIZE`: `bufferSize` to create `SharedArrayBuffer` for `worker_threads` (default as `1024`)
-2. `SYNCKIT_TIMEOUT`: `timeout` for performing the async job (no default)
-3. `SYNCKIT_EXEC_ARGV`: List of node CLI options passed to the worker, split with comma `,`. (default as `[]`), see also [`node` docs](https://nodejs.org/api/worker_threads.html)
-4. `SYNCKIT_TS_RUNNER`: Which TypeScript runner to be used, it could be very useful for development, could be `'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'swc' | 'tsx'`, `'ts-node'` is used by default, make sure you have installed them already
-5. `SYNCKIT_GLOBAL_SHIMS`: Whether to enable the default `DEFAULT_GLOBAL_SHIMS_PRESET` as `globalShims`
+1. `SYNCKIT_TIMEOUT`: `timeout` for performing the async job (no default)
+2. `SYNCKIT_EXEC_ARGV`: List of node CLI options passed to the worker, split with comma `,`. (default as `[]`), see also [`node` docs](https://nodejs.org/api/worker_threads.html)
+3. `SYNCKIT_TS_RUNNER`: Which TypeScript runner to be used, it could be very useful for development, could be `'ts-node' | 'esbuild-register' | 'esbuild-runner' | 'swc' | 'tsx'`, `'ts-node'` is used by default, make sure you have installed them already
+4. `SYNCKIT_GLOBAL_SHIMS`: Whether to enable the default `DEFAULT_GLOBAL_SHIMS_PRESET` as `globalShims`
 
 ### TypeScript
 

src/index.ts

@@ -26,6 +26,8 @@ import type {
   WorkerToMainMessage,
 } from './types.js'
 
+const INT32_BYTES = 4
+
 export * from './types.js'
 
 export const TsRunner = {
@@ -44,22 +46,15 @@ export const TsRunner = {
 export type TsRunner = ValueOf<typeof TsRunner>
 
 const {
-  SYNCKIT_BUFFER_SIZE,
   SYNCKIT_TIMEOUT,
   SYNCKIT_EXEC_ARGV,
   SYNCKIT_TS_RUNNER,
   SYNCKIT_GLOBAL_SHIMS,
   NODE_OPTIONS,
 } = process.env
 
-export const DEFAULT_BUFFER_SIZE = SYNCKIT_BUFFER_SIZE
-  ? +SYNCKIT_BUFFER_SIZE
-  : undefined
-
 export const DEFAULT_TIMEOUT = SYNCKIT_TIMEOUT ? +SYNCKIT_TIMEOUT : undefined
 
-export const DEFAULT_WORKER_BUFFER_SIZE = DEFAULT_BUFFER_SIZE || 1024
-
 /* istanbul ignore next */
 export const DEFAULT_EXEC_ARGV = SYNCKIT_EXEC_ARGV?.split(',') || []
 
@@ -86,7 +81,6 @@ export const MTS_SUPPORTED_NODE_VERSION = 16
 const syncFnCache = new Map<string, AnyFn>()
 
 export interface SynckitOptions {
-  bufferSize?: number
   timeout?: number
   execArgv?: string[]
   tsRunner?: TsRunner
@@ -109,40 +103,30 @@ export function extractProperties<T>(object?: T) {
   }
 }
 
-export function createSyncFn<T extends AnyAsyncFn>(
-  workerPath: string,
-  bufferSize?: number,
-  timeout?: number,
-): Syncify<T>
-export function createSyncFn<T extends AnyAsyncFn>(
-  workerPath: string,
-  options?: SynckitOptions,
-): Syncify<T>
-export function createSyncFn<R, T extends AnyAsyncFn<R>>(
+export function createSyncFn<T extends AnyAsyncFn<R>, R = unknown>(
   workerPath: string,
-  bufferSizeOrOptions?: SynckitOptions | number,
-  timeout?: number,
-) {
+  timeoutOrOptions?: SynckitOptions | number,
+): Syncify<T> {
   if (!path.isAbsolute(workerPath)) {
     throw new Error('`workerPath` must be absolute')
   }
 
   const cachedSyncFn = syncFnCache.get(workerPath)
 
   if (cachedSyncFn) {
-    return cachedSyncFn
+    return cachedSyncFn as Syncify<T>
   }
 
   const syncFn = startWorkerThread<R, T>(
     workerPath,
-    /* istanbul ignore next */ typeof bufferSizeOrOptions === 'number'
-      ? { bufferSize: bufferSizeOrOptions, timeout }
-      : bufferSizeOrOptions,
+    /* istanbul ignore next */ typeof timeoutOrOptions === 'number'
+      ? { timeout: timeoutOrOptions }
+      : timeoutOrOptions,
   )
 
   syncFnCache.set(workerPath, syncFn)
 
-  return syncFn
+  return syncFn as Syncify<T>
 }
 
 const cjsRequire =
@@ -421,7 +405,6 @@ export const generateGlobals = (
 function startWorkerThread<R, T extends AnyAsyncFn<R>>(
   workerPath: string,
   {
-    bufferSize = DEFAULT_WORKER_BUFFER_SIZE,
     timeout = DEFAULT_TIMEOUT,
     execArgv = DEFAULT_EXEC_ARGV,
     tsRunner = DEFAULT_TS_RUNNER,
@@ -480,6 +463,11 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
       : []
   ).filter(({ moduleName }) => isPkgAvailable(moduleName))
 
+  // We store a single Byte in the SharedArrayBuffer
+  // for the notification, we can used a fixed size
+  const sharedBuffer = new SharedArrayBuffer(INT32_BYTES)
+  const sharedBufferView = new Int32Array(sharedBuffer, 0, 1)
+
   const useGlobals = finalGlobalShims.length > 0
 
   const useEval = isTs ? !tsUseEsm : !jsUseEsm && useGlobals
@@ -501,7 +489,7 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
       : workerPathUrl,
     {
       eval: useEval,
-      workerData: { workerPort },
+      workerData: { sharedBuffer, workerPort },
       transferList: [workerPort, ...transferList],
       execArgv: finalExecArgv,
     },
@@ -512,13 +500,12 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
   const syncFn = (...args: Parameters<T>): R => {
     const id = nextID++
 
-    const sharedBuffer = new SharedArrayBuffer(bufferSize)
-    const sharedBufferView = new Int32Array(sharedBuffer)
-
-    const msg: MainToWorkerMessage<Parameters<T>> = { sharedBuffer, id, args }
+    const msg: MainToWorkerMessage<Parameters<T>> = { id, args }
     worker.postMessage(msg)
 
     const status = Atomics.wait(sharedBufferView, 0, 0, timeout)
+    // Reset SharedArrayBuffer for next call
+    Atomics.store(sharedBufferView, 0, 0)
 
     /* istanbul ignore if */
     if (!['ok', 'not-equal'].includes(status)) {
@@ -560,14 +547,14 @@ export function runAsWorker<
     return
   }
 
-  const { workerPort } = workerData as WorkerData
+  const { workerPort, sharedBuffer } = workerData as WorkerData
+  const sharedBufferView = new Int32Array(sharedBuffer, 0, 1)
 
   parentPort!.on(
     'message',
-    ({ sharedBuffer, id, args }: MainToWorkerMessage<Parameters<T>>) => {
+    ({ id, args }: MainToWorkerMessage<Parameters<T>>) => {
       // eslint-disable-next-line @typescript-eslint/no-floating-promises
       ;(async () => {
-        const sharedBufferView = new Int32Array(sharedBuffer)
         let msg: WorkerToMainMessage<R>
         try {
           msg = { id, result: await fn(...args) }

src/types.ts

@@ -22,12 +22,12 @@ export type PromiseType<T extends AnyPromise> = T extends Promise<infer R>
 export type ValueOf<T> = T[keyof T]
 
 export interface MainToWorkerMessage<T extends unknown[]> {
-  sharedBuffer: SharedArrayBuffer
   id: number
   args: T
 }
 
 export interface WorkerData {
+  sharedBuffer: SharedArrayBuffer
   workerPort: MessagePort
 }
 

test/fn.spec.ts

@@ -13,7 +13,6 @@ const { SYNCKIT_TIMEOUT } = process.env
 beforeEach(() => {
   jest.resetModules()
 
-  delete process.env.SYNCKIT_BUFFER_SIZE
   delete process.env.SYNCKIT_GLOBAL_SHIMS
 
   if (SYNCKIT_TIMEOUT) {
@@ -95,7 +94,6 @@ test('createSyncFn', () => {
 })
 
 test('timeout', async () => {
-  process.env.SYNCKIT_BUFFER_SIZE = '0'
   process.env.SYNCKIT_TIMEOUT = '1'
 
   const { createSyncFn } = await import('synckit')

test/ts-runner.spec.ts

@@ -134,8 +134,8 @@ test('unknown ts runner', async () => {
   const { createSyncFn } = await import('synckit')
 
   expect(() =>
-    // @ts-expect-error
     createSyncFn<AsyncWorkerFn>(path.resolve(_dirname, 'worker.js'), {
+      // @ts-expect-error
       tsRunner: 'unknown',
     }),
   ).toThrowErrorMatchingInlineSnapshot(`"Unknown ts runner: unknown"`)