redis/internal/pool/conn_stack.go

75 lines
1.2 KiB
Go

package pool
import (
"sync"
"time"
)
// connStack is used as a LIFO to maintain free connections
type connStack struct {
cns []*Conn
free chan struct{}
mu sync.Mutex
}
func newConnStack(max int) *connStack {
return &connStack{
cns: make([]*Conn, 0, max),
free: make(chan struct{}, max),
}
}
func (s *connStack) Len() int { return len(s.free) }
func (s *connStack) Push(cn *Conn) {
s.mu.Lock()
s.cns = append(s.cns, cn)
s.mu.Unlock()
s.free <- struct{}{}
}
func (s *connStack) ShiftStale(idleTimeout time.Duration) *Conn {
select {
case <-s.free:
s.mu.Lock()
defer s.mu.Unlock()
if cn := s.cns[0]; cn.IsStale(idleTimeout) {
copy(s.cns, s.cns[1:])
s.cns = s.cns[:len(s.cns)-1]
return cn
}
s.free <- struct{}{}
return nil
default:
return nil
}
}
func (s *connStack) Pop() *Conn {
select {
case <-s.free:
return s.pop()
default:
return nil
}
}
func (s *connStack) PopWithTimeout(d time.Duration) *Conn {
select {
case <-s.free:
return s.pop()
case <-time.After(d):
return nil
}
}
func (s *connStack) pop() (cn *Conn) {
s.mu.Lock()
ci := len(s.cns) - 1
cn, s.cns = s.cns[ci], s.cns[:ci]
s.mu.Unlock()
return
}