79 lines
1.4 KiB
Go
79 lines
1.4 KiB
Go
package sftp
|
|
|
|
// bufPool provides a pool of byte-slices to be reused in various parts of the package.
|
|
// It is safe to use concurrently through a pointer.
|
|
type bufPool struct {
|
|
ch chan []byte
|
|
blen int
|
|
}
|
|
|
|
func newBufPool(depth, bufLen int) *bufPool {
|
|
return &bufPool{
|
|
ch: make(chan []byte, depth),
|
|
blen: bufLen,
|
|
}
|
|
}
|
|
|
|
func (p *bufPool) Get() []byte {
|
|
if p.blen <= 0 {
|
|
panic("bufPool: new buffer creation length must be greater than zero")
|
|
}
|
|
|
|
for {
|
|
select {
|
|
case b := <-p.ch:
|
|
if cap(b) < p.blen {
|
|
// just in case: throw away any buffer with insufficient capacity.
|
|
continue
|
|
}
|
|
|
|
return b[:p.blen]
|
|
|
|
default:
|
|
return make([]byte, p.blen)
|
|
}
|
|
}
|
|
}
|
|
|
|
func (p *bufPool) Put(b []byte) {
|
|
if p == nil {
|
|
// functional default: no reuse.
|
|
return
|
|
}
|
|
|
|
if cap(b) < p.blen || cap(b) > p.blen*2 {
|
|
// DO NOT reuse buffers with insufficient capacity.
|
|
// This could cause panics when resizing to p.blen.
|
|
|
|
// DO NOT reuse buffers with excessive capacity.
|
|
// This could cause memory leaks.
|
|
return
|
|
}
|
|
|
|
select {
|
|
case p.ch <- b:
|
|
default:
|
|
}
|
|
}
|
|
|
|
type resChanPool chan chan result
|
|
|
|
func newResChanPool(depth int) resChanPool {
|
|
return make(chan chan result, depth)
|
|
}
|
|
|
|
func (p resChanPool) Get() chan result {
|
|
select {
|
|
case ch := <-p:
|
|
return ch
|
|
default:
|
|
return make(chan result, 1)
|
|
}
|
|
}
|
|
|
|
func (p resChanPool) Put(ch chan result) {
|
|
select {
|
|
case p <- ch:
|
|
default:
|
|
}
|
|
}
|