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go-zero/core/syncx/limit.go

43 lines
694 B
Go

package syncx
import (
"errors"
"zero/core/lang"
)
var ErrReturn = errors.New("discarding limited token, resource pool is full, someone returned multiple times")
type Limit struct {
pool chan lang.PlaceholderType
}
func NewLimit(n int) Limit {
return Limit{
pool: make(chan lang.PlaceholderType, n),
}
}
func (l Limit) Borrow() {
l.pool <- lang.Placeholder
}
// Return returns the borrowed resource, returns error only if returned more than borrowed.
func (l Limit) Return() error {
select {
case <-l.pool:
return nil
default:
return ErrReturn
}
}
func (l Limit) TryBorrow() bool {
select {
case l.pool <- lang.Placeholder:
return true
default:
return false
}
}