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author | Quentin Dufour <quentin@deuxfleurs.fr> | 2021-11-19 19:54:49 +0100 |
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committer | Quentin Dufour <quentin@deuxfleurs.fr> | 2021-11-19 19:54:49 +0100 |
commit | 0ee29e31ddcc81f541de7459b0a5e40dfa552672 (patch) | |
tree | 859ff133f8c78bd034b0c2184cdad0ce9f38b065 /sftp/pool.go | |
parent | 93631b4e3d5195d446504db1c4a2bc7468b3ef28 (diff) | |
download | bagage-0ee29e31ddcc81f541de7459b0a5e40dfa552672.tar.gz bagage-0ee29e31ddcc81f541de7459b0a5e40dfa552672.zip |
Working on SFTP
Diffstat (limited to 'sftp/pool.go')
-rw-r--r-- | sftp/pool.go | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/sftp/pool.go b/sftp/pool.go new file mode 100644 index 0000000..3612629 --- /dev/null +++ b/sftp/pool.go @@ -0,0 +1,79 @@ +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: + } +} |