package gpool

type GJobFunc func(arg ...interface{})

type GJob struct {
    f   GJobFunc
    arg []interface{}
}

type GWorker struct {
    g    *GPool
    jobC chan *GJob
    done chan interface{}
}

type GPool struct {
    workerList []*GWorker
    workers    chan *GWorker
    jobs       chan *GJob
    done       chan interface{}
}

func NewGPool(workerMaxNum, jobMaxNum int) *GPool {
    g := &GPool{
        workerList: make([]*GWorker, workerMaxNum),
        workers:    make(chan *GWorker, workerMaxNum),
        jobs:       make(chan *GJob, jobMaxNum),
        done:       make(chan interface{}, 1),
    }

    for i := 0; i < workerMaxNum; i++ {
        w := &GWorker{
            g:    g,
            jobC: make(chan *GJob, 1),
            done: make(chan interface{}, 1),
        }
        g.workerList[i] = w
        go w.run()
    }

    go g.dispatch()

    return g
}

func (g *GPool) Free() {
    go func() {
        g.done <- struct{}{}
        for _, w := range g.workerList {
            w.stop()
        }
    }()
}

func (g *GPool) AddJob(f GJobFunc, arg ...interface{}) {
    g.jobs <- &GJob{
        f:   f,
        arg: arg,
    }
}

func (g *GPool) dispatch() {
    for {
        select {
        case job := <-g.jobs:
            g.getWorker().putJob(job)
        case <-g.done:
            return
        }
    }
}

func (g *GPool) putWorker(w *GWorker) {
    g.workers <- w
}

func (g *GPool) getWorker() *GWorker {
    return <-g.workers
}

func (w *GWorker) run() {
    for {
        w.g.putWorker(w)
        select {
        case job := <-w.jobC:
            job.f(job.arg...)
        case <-w.done:
            return
        }

    }
}

func (w *GWorker) stop() {
    w.done <- struct{}{}
}

func (w *GWorker) putJob(job *GJob) {
    w.jobC <- job
}

package test_gpool

import (
    "fmt"
    "gpool"
    "math/rand"
    "sync"
    "time"
)

func TestGPool() {
    wg := &sync.WaitGroup{}
    wg.Add(30)

    g := gpool.NewGPool(10, 100)
    defer g.Free()

    for i := 0; i < 30; i++ {
        now := time.Now()
        g.AddJob(TestTask, now, wg, i, i*30)
    }

    wg.Wait()
}

func TestTask(arg ...interface{}) {
    fmt.Println(time.Now().Format("[2006-01-02 15:04:05.000000]"), arg)
    time.Sleep(time.Duration(rand.Intn(10))*time.Second)
    wg := arg[1].(*sync.WaitGroup)
    wg.Done()
}

package semaphore

import "time"

type Semaphore struct {
    channel chan interface{}
}

/* 創建信號量 */
func NewSemaphore(permits int) *Semaphore {
    return &Semaphore{channel: make(chan interface{}, permits)}
}

/* 獲取許可 */
func (s *Semaphore) Acquire() {
    s.channel <- struct{}{}
}

/* 釋放許可 */
func (s *Semaphore) Release() {
    <-s.channel
}

/* 嘗試獲取許可 */
func (s *Semaphore) TryAcquire() bool {
    select {
    case s.channel <- struct{}{}:
        return true
    default:
        return false
    }
}

/* 嘗試指定時間內獲取許可 */
func (s *Semaphore) TryAcquireOnTime(timeout time.Duration) bool {
    for {
        select {
        case s.channel <- struct{}{}:
            return true
        case <-time.After(timeout):
            return false
        }
    }
}

/* 當前可用的許可數 */
func (s *Semaphore) AvailablePermits() int {
    return cap(s.channel) - len(s.channel)
}