sync

package
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Published: Mar 8, 2023 License: LGPL-3.0 Imports: 5 Imported by: 0

Documentation

Overview

Package sync provides extra synchronization facilities such as semaphore in addition to the standard sync package.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Semaphore

type Semaphore struct {
	// contains filtered or unexported fields
}

Semaphore is a mimic of the POSIX semaphore based on channel and sync.Mutex. It could be used to limit the number of concurrent running goroutines. Basic example:

// Creates a ready-to-use semaphore
sema := concurrent.NewSemaphore(InitValue)
// Decrements the semaphore, blocks if value of the semaphore is less than 1
semaResource := sema.Acquire()
// Increments the semaphore. If the semaphore's value consequently becomes greater than zero,
// then another goroutine blocked in sema.Acquire() will be woken up and acquire the resources.
semaResource.Release()

func NewSemaphore

func NewSemaphore(value int) *Semaphore

NewSemaphore creates a ready-to-use Semaphore.

value: Initial value of the Semaphore.
Example

This example shows the basic usage of Semaphore.

package main

import (
	"github.com/antigloss/go/sync"
	"time"
)

func main() {
	// Create a ready-to-use semaphore
	sema := sync.NewSemaphore(10)
	// Block to acquire resources from the semaphore
	semaResource := sema.Acquire()
	// Release resources acquired from a semaphore
	semaResource.Release()
	// Try to acquire resources from the semaphore, returns nil if resources cannot be acquired immediately
	semaResource = sema.TryAcquire()
	if semaResource != nil {
		// Release resources acquired from a semaphore
		semaResource.Release()
	}
	// Wait at most 2 seconds to acquire resources from the semaphore, returns nil if resources cannot be acquired after timeout
	semaResource = sema.TimedAcquire(2 * time.Second)
	if semaResource != nil {
		// Release resources acquired from a semaphore
		semaResource.Release()
	}
}
Output:

func (*Semaphore) Acquire

func (s *Semaphore) Acquire() *SemaphoreResource

Acquire decrements the semaphore, blocks if value of the semaphore is less than 1.

func (*Semaphore) TimedAcquire

func (s *Semaphore) TimedAcquire(duration time.Duration) (sr *SemaphoreResource)

TimedAcquire waits at most a given time to decrement the semaphore. It returns nil if the decrement cannot be done after the given timeout.

func (*Semaphore) TryAcquire

func (s *Semaphore) TryAcquire() (sr *SemaphoreResource)

TryAcquire tries to decrement the semaphore. It returns nil if the decrement cannot be done immediately.

type SemaphoreResource

type SemaphoreResource struct {
	// contains filtered or unexported fields
}

SemaphoreResource holds resources acquired from a Semaphore object.

func (*SemaphoreResource) Release

func (sr *SemaphoreResource) Release()

Release releases resources acquired from a Semaphore object.

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