packer-cn/vendor/github.com/cheggaaa/pb/pool.go

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// +build linux darwin freebsd netbsd openbsd solaris dragonfly windows
package pb
import (
"io"
"sync"
"time"
)
// Create and start new pool with given bars
// You need call pool.Stop() after work
func StartPool(pbs ...*ProgressBar) (pool *Pool, err error) {
pool = new(Pool)
if err = pool.Start(); err != nil {
return
}
pool.Add(pbs...)
return
}
// NewPool initialises a pool with progress bars, but
// doesn't start it. You need to call Start manually
func NewPool(pbs ...*ProgressBar) (pool *Pool) {
pool = new(Pool)
pool.Add(pbs...)
return
}
type Pool struct {
Output io.Writer
RefreshRate time.Duration
bars []*ProgressBar
lastBarsCount int
shutdownCh chan struct{}
workerCh chan struct{}
m sync.Mutex
finishOnce sync.Once
}
// Add progress bars.
func (p *Pool) Add(pbs ...*ProgressBar) {
p.m.Lock()
defer p.m.Unlock()
for _, bar := range pbs {
bar.ManualUpdate = true
bar.NotPrint = true
bar.Start()
p.bars = append(p.bars, bar)
}
}
func (p *Pool) Start() (err error) {
p.RefreshRate = DefaultRefreshRate
p.shutdownCh, err = lockEcho()
if err != nil {
return
}
p.workerCh = make(chan struct{})
go p.writer()
return
}
func (p *Pool) writer() {
var first = true
defer func() {
if first == false {
p.print(false)
} else {
p.print(true)
p.print(false)
}
close(p.workerCh)
}()
for {
select {
case <-time.After(p.RefreshRate):
if p.print(first) {
p.print(false)
return
}
first = false
case <-p.shutdownCh:
return
}
}
}
// Restore terminal state and close pool
func (p *Pool) Stop() error {
p.finishOnce.Do(func() {
close(p.shutdownCh)
})
// Wait for the worker to complete
select {
case <-p.workerCh:
}
return unlockEcho()
}