prometheus-adapter/vendor/github.com/emicklei/go-restful/compressor_cache.go
Solly Ross a293b2bf94 Check in the vendor directory
Travis seems to be having issues pulling deps, so we'll have to check in
the vendor directory and prevent the makefile from trying to regenerate
it normally.
2018-07-13 17:32:49 -04:00

103 lines
3.1 KiB
Go

package restful
// Copyright 2015 Ernest Micklei. All rights reserved.
// Use of this source code is governed by a license
// that can be found in the LICENSE file.
import (
"compress/gzip"
"compress/zlib"
)
// BoundedCachedCompressors is a CompressorProvider that uses a cache with a fixed amount
// of writers and readers (resources).
// If a new resource is acquired and all are in use, it will return a new unmanaged resource.
type BoundedCachedCompressors struct {
gzipWriters chan *gzip.Writer
gzipReaders chan *gzip.Reader
zlibWriters chan *zlib.Writer
writersCapacity int
readersCapacity int
}
// NewBoundedCachedCompressors returns a new, with filled cache, BoundedCachedCompressors.
func NewBoundedCachedCompressors(writersCapacity, readersCapacity int) *BoundedCachedCompressors {
b := &BoundedCachedCompressors{
gzipWriters: make(chan *gzip.Writer, writersCapacity),
gzipReaders: make(chan *gzip.Reader, readersCapacity),
zlibWriters: make(chan *zlib.Writer, writersCapacity),
writersCapacity: writersCapacity,
readersCapacity: readersCapacity,
}
for ix := 0; ix < writersCapacity; ix++ {
b.gzipWriters <- newGzipWriter()
b.zlibWriters <- newZlibWriter()
}
for ix := 0; ix < readersCapacity; ix++ {
b.gzipReaders <- newGzipReader()
}
return b
}
// AcquireGzipWriter returns an resettable *gzip.Writer. Needs to be released.
func (b *BoundedCachedCompressors) AcquireGzipWriter() *gzip.Writer {
var writer *gzip.Writer
select {
case writer, _ = <-b.gzipWriters:
default:
// return a new unmanaged one
writer = newGzipWriter()
}
return writer
}
// ReleaseGzipWriter accepts a writer (does not have to be one that was cached)
// only when the cache has room for it. It will ignore it otherwise.
func (b *BoundedCachedCompressors) ReleaseGzipWriter(w *gzip.Writer) {
// forget the unmanaged ones
if len(b.gzipWriters) < b.writersCapacity {
b.gzipWriters <- w
}
}
// AcquireGzipReader returns a *gzip.Reader. Needs to be released.
func (b *BoundedCachedCompressors) AcquireGzipReader() *gzip.Reader {
var reader *gzip.Reader
select {
case reader, _ = <-b.gzipReaders:
default:
// return a new unmanaged one
reader = newGzipReader()
}
return reader
}
// ReleaseGzipReader accepts a reader (does not have to be one that was cached)
// only when the cache has room for it. It will ignore it otherwise.
func (b *BoundedCachedCompressors) ReleaseGzipReader(r *gzip.Reader) {
// forget the unmanaged ones
if len(b.gzipReaders) < b.readersCapacity {
b.gzipReaders <- r
}
}
// AcquireZlibWriter returns an resettable *zlib.Writer. Needs to be released.
func (b *BoundedCachedCompressors) AcquireZlibWriter() *zlib.Writer {
var writer *zlib.Writer
select {
case writer, _ = <-b.zlibWriters:
default:
// return a new unmanaged one
writer = newZlibWriter()
}
return writer
}
// ReleaseZlibWriter accepts a writer (does not have to be one that was cached)
// only when the cache has room for it. It will ignore it otherwise.
func (b *BoundedCachedCompressors) ReleaseZlibWriter(w *zlib.Writer) {
// forget the unmanaged ones
if len(b.zlibWriters) < b.writersCapacity {
b.zlibWriters <- w
}
}