cubefs/blobstore/common/resourcepool/pool.go
slasher 06fe80aded build: add blobstore module access
Signed-off-by: slasher <mcq.sejust@gmail.com>
2022-10-12 10:21:39 +08:00

86 lines
2.1 KiB
Go

// Copyright 2022 The CubeFS Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
// implied. See the License for the specific language governing
// permissions and limitations under the License.
package resourcepool
// sync.Pool cache will be released by runtime.GC()
// see sync/pool.go: runtime_registerPoolCleanup(poolCleanup)
import (
"errors"
"sync"
"sync/atomic"
)
// ErrPoolLimit pool elements exceed its capacity
var ErrPoolLimit = errors.New("resource pool limit")
// Pool resource pool support for sync.pool and capacity limit
// release resource if no used anymore
// no limit if capacity is negative
type Pool interface {
// Get return nil and error if exceed pool's capacity
Get() (interface{}, error)
Put(x interface{})
Cap() int
Len() int
// Idle return cached idle objects in pool.
Idle() int
}
// sync pool Idle return -1 if no limit
type pool struct {
sp sync.Pool
capacity int32
current int32
}
// NewPool return Pool with capacity, no limit if capacity is negative
func NewPool(newFunc func() interface{}, capacity int) Pool {
return &pool{
sp: sync.Pool{New: newFunc},
capacity: int32(capacity),
current: int32(0),
}
}
func (p *pool) Get() (interface{}, error) {
current := atomic.AddInt32(&p.current, 1)
if p.capacity >= 0 && current > p.capacity {
atomic.AddInt32(&p.current, -1)
return nil, ErrPoolLimit
}
return p.sp.Get(), nil
}
func (p *pool) Put(x interface{}) {
p.sp.Put(x)
atomic.AddInt32(&p.current, -1)
}
func (p *pool) Cap() int {
return int(p.capacity)
}
func (p *pool) Len() int {
return int(atomic.LoadInt32(&p.current))
}
func (p *pool) Idle() int {
if p.capacity < 0 {
return -1
}
return p.Cap() - p.Len()
}