X-Git-Url: https://git.piment-noir.org/?a=blobdiff_plain;f=src%2Futils.ts;h=88562ca3531f9acbb446414075366a4b50ba1ce4;hb=03e74987448abc5e2c044953270c23e02b609136;hp=7b921ffa4b94efcfd673b75248e44ee305466058;hpb=932fc8be063cc15b543ad14c2ab6df0fa4224fba;p=poolifier.git

diff --git a/src/utils.ts b/src/utils.ts
index 7b921ffa..88562ca3 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -1,4 +1,12 @@
-import type { WorkerChoiceStrategyOptions } from './pools/selection-strategies/selection-strategies-types'
+import { getRandomValues } from 'node:crypto'
+import * as os from 'node:os'
+
+import type { KillBehavior } from './worker/worker-options.js'
+
+/**
+ * Default task name.
+ */
+export const DEFAULT_TASK_NAME = 'default'
 
 /**
  * An intentional empty function.
@@ -8,25 +16,84 @@ export const EMPTY_FUNCTION: () => void = Object.freeze(() => {
 })
 
 /**
- * Default worker choice strategy options.
+ * Returns safe host OS optimized estimate of the default amount of parallelism a pool should use.
+ * Always returns a value greater than zero.
+ *
+ * @returns The host OS optimized maximum pool size.
+ */
+export const availableParallelism = (): number => {
+  let availableParallelism = 1
+  try {
+    availableParallelism = os.availableParallelism()
+  } catch {
+    const cpus = os.cpus()
+    if (Array.isArray(cpus) && cpus.length > 0) {
+      availableParallelism = cpus.length
+    }
+  }
+  return availableParallelism
+}
+
+/**
+ * Sleeps for the given amount of milliseconds.
+ *
+ * @param ms - The amount of milliseconds to sleep.
+ * @returns A promise that resolves after the given amount of milliseconds.
+ * @internal
+ */
+export const sleep = async (ms: number): Promise<void> => {
+  await new Promise(resolve => {
+    setTimeout(resolve, ms)
+  })
+}
+
+/**
+ * Computes the retry delay in milliseconds using an exponential back off algorithm.
+ *
+ * @param retryNumber - The number of retries that have already been attempted
+ * @param delayFactor - The base delay factor in milliseconds
+ * @returns Delay in milliseconds
+ * @internal
+ */
+export const exponentialDelay = (
+  retryNumber = 0,
+  delayFactor = 100
+): number => {
+  const delay = Math.pow(2, retryNumber) * delayFactor
+  const randomSum = delay * 0.2 * secureRandom() // 0-20% of the delay
+  return delay + randomSum
+}
+
+/**
+ * Computes the average of the given data set.
+ *
+ * @param dataSet - Data set.
+ * @returns The average of the given data set.
+ * @internal
  */
-export const DEFAULT_WORKER_CHOICE_STRATEGY_OPTIONS: WorkerChoiceStrategyOptions =
-  {
-    runTime: { median: false },
-    waitTime: { median: false }
+export const average = (dataSet: number[]): number => {
+  if (Array.isArray(dataSet) && dataSet.length === 0) {
+    return 0
+  } else if (Array.isArray(dataSet) && dataSet.length === 1) {
+    return dataSet[0]
   }
+  return (
+    dataSet.reduce((accumulator, number) => accumulator + number, 0) /
+    dataSet.length
+  )
+}
 
 /**
- * Compute the median of the given data set.
+ * Computes the median of the given data set.
  *
  * @param dataSet - Data set.
  * @returns The median of the given data set.
+ * @internal
  */
 export const median = (dataSet: number[]): number => {
   if (Array.isArray(dataSet) && dataSet.length === 0) {
     return 0
-  }
-  if (Array.isArray(dataSet) && dataSet.length === 1) {
+  } else if (Array.isArray(dataSet) && dataSet.length === 1) {
     return dataSet[0]
   }
   const sortedDataSet = dataSet.slice().sort((a, b) => a - b)
@@ -38,13 +105,114 @@ export const median = (dataSet: number[]): number => {
 }
 
 /**
- * Is the given object a plain object?
+ * Rounds the given number to the given scale.
+ * The rounding is done using the "round half away from zero" method.
  *
- * @param obj - The object to check.
- * @returns `true` if the given object is a plain object, `false` otherwise.
+ * @param num - The number to round.
+ * @param scale - The scale to round to.
+ * @returns The rounded number.
+ * @internal
  */
-export const isPlainObject = (obj: unknown): boolean =>
-  typeof obj === 'object' &&
-  obj !== null &&
-  obj?.constructor === Object &&
-  Object.prototype.toString.call(obj) === '[object Object]'
+export const round = (num: number, scale = 2): number => {
+  const rounder = Math.pow(10, scale)
+  return Math.round(num * rounder * (1 + Number.EPSILON)) / rounder
+}
+
+/**
+ * Is the given value a plain object?
+ *
+ * @param value - The value to check.
+ * @returns `true` if the given value is a plain object, `false` otherwise.
+ * @internal
+ */
+export const isPlainObject = (value: unknown): value is object =>
+  typeof value === 'object' &&
+  value !== null &&
+  value.constructor === Object &&
+  Object.prototype.toString.call(value) === '[object Object]'
+
+/**
+ * Detects whether the given value is a kill behavior or not.
+ *
+ * @typeParam KB - Which specific KillBehavior type to test against.
+ * @param killBehavior - Which kind of kill behavior to detect.
+ * @param value - Unknown value.
+ * @returns `true` if `value` was strictly equals to `killBehavior`, otherwise `false`.
+ * @internal
+ */
+export const isKillBehavior = <KB extends KillBehavior>(
+  killBehavior: KB,
+  value: unknown
+): value is KB => {
+  return value === killBehavior
+}
+
+/**
+ * Detects whether the given value is an asynchronous function or not.
+ *
+ * @param fn - Unknown value.
+ * @returns `true` if `fn` was an asynchronous function, otherwise `false`.
+ * @internal
+ */
+export const isAsyncFunction = (
+  fn: unknown
+): fn is (...args: unknown[]) => Promise<unknown> => {
+  return typeof fn === 'function' && fn.constructor.name === 'AsyncFunction'
+}
+
+/**
+ * Generates a cryptographically secure random number in the [0,1[ range
+ *
+ * @returns A number in the [0,1[ range
+ * @internal
+ */
+export const secureRandom = (): number => {
+  return getRandomValues(new Uint32Array(1))[0] / 0x100000000
+}
+
+/**
+ * Returns the minimum of the given numbers.
+ * If no numbers are given, `Infinity` is returned.
+ *
+ * @param args - The numbers to get the minimum of.
+ * @returns The minimum of the given numbers.
+ * @internal
+ */
+export const min = (...args: number[]): number =>
+  args.reduce((minimum, num) => (minimum < num ? minimum : num), Infinity)
+
+/**
+ * Returns the maximum of the given numbers.
+ * If no numbers are given, `-Infinity` is returned.
+ *
+ * @param args - The numbers to get the maximum of.
+ * @returns The maximum of the given numbers.
+ * @internal
+ */
+export const max = (...args: number[]): number =>
+  args.reduce((maximum, num) => (maximum > num ? maximum : num), -Infinity)
+
+/**
+ * Wraps a function so that it can only be called once.
+ *
+ * @param fn - The function to wrap.
+ * @param context - The context to bind the function to.
+ * @returns The wrapped function.
+ * @internal
+ */
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const once = <A extends any[], R, T>(
+  fn: (...args: A) => R,
+  context: T
+): ((...args: A) => R) => {
+  let result: R
+  return (...args: A) => {
+    // eslint-disable-next-line @typescript-eslint/no-unnecessary-condition
+    if (fn != null) {
+      result = fn.apply<T, A, R>(context, args)
+      ;(fn as unknown as undefined) = (context as unknown as undefined) =
+        undefined
+    }
+    return result
+  }
+}