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