github.com/hanwen/go-fuse@v1.0.0/splice/pool.go (about) 1 // Copyright 2016 the Go-FUSE Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package splice 6 7 import ( 8 "sync" 9 ) 10 11 var splicePool *pairPool 12 13 type pairPool struct { 14 sync.Mutex 15 unused []*Pair 16 usedCount int 17 } 18 19 func ClearSplicePool() { 20 splicePool.clear() 21 } 22 23 func Get() (*Pair, error) { 24 return splicePool.get() 25 } 26 27 func Total() int { 28 return splicePool.total() 29 } 30 31 func Used() int { 32 return splicePool.used() 33 } 34 35 // Done returns the pipe pair to pool. 36 func Done(p *Pair) { 37 splicePool.done(p) 38 } 39 40 // Closes and discards pipe pair. 41 func Drop(p *Pair) { 42 splicePool.drop(p) 43 } 44 45 func newSplicePairPool() *pairPool { 46 return &pairPool{} 47 } 48 49 func (pp *pairPool) clear() { 50 pp.Lock() 51 for _, p := range pp.unused { 52 p.Close() 53 } 54 pp.unused = pp.unused[:0] 55 pp.Unlock() 56 } 57 58 func (pp *pairPool) used() (n int) { 59 pp.Lock() 60 n = pp.usedCount 61 pp.Unlock() 62 63 return n 64 } 65 66 func (pp *pairPool) total() int { 67 pp.Lock() 68 n := pp.usedCount + len(pp.unused) 69 pp.Unlock() 70 return n 71 } 72 73 func (pp *pairPool) drop(p *Pair) { 74 p.Close() 75 pp.Lock() 76 pp.usedCount-- 77 pp.Unlock() 78 } 79 80 func (pp *pairPool) get() (p *Pair, err error) { 81 pp.Lock() 82 defer pp.Unlock() 83 84 pp.usedCount++ 85 l := len(pp.unused) 86 if l > 0 { 87 p := pp.unused[l-1] 88 pp.unused = pp.unused[:l-1] 89 return p, nil 90 } 91 92 return newSplicePair() 93 } 94 95 func (pp *pairPool) done(p *Pair) { 96 p.discard() 97 98 pp.Lock() 99 pp.usedCount-- 100 pp.unused = append(pp.unused, p) 101 pp.Unlock() 102 } 103 104 func init() { 105 splicePool = newSplicePairPool() 106 }