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