forked from segmentio/kafka-go
/
lz4.go
81 lines (66 loc) · 1.57 KB
/
lz4.go
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package lz4
import (
"bytes"
"io/ioutil"
"sync"
"github.com/pierrec/lz4"
"github.com/segmentio/kafka-go"
)
var (
readerPool sync.Pool
writerPool sync.Pool
)
func init() {
readerPool = sync.Pool{
New: func() interface{} {
return lz4.NewReader(nil)
},
}
writerPool = sync.Pool{
New: func() interface{} {
return lz4.NewWriter(nil)
},
}
kafka.RegisterCompressionCodec(func() kafka.CompressionCodec {
return NewCompressionCodec()
})
}
type CompressionCodec struct{}
const Code = 3
func NewCompressionCodec() CompressionCodec {
return CompressionCodec{}
}
// Code implements the kafka.CompressionCodec interface.
func (c CompressionCodec) Code() int8 {
return Code
}
// Encode implements the kafka.CompressionCodec interface.
func (c CompressionCodec) Encode(src []byte) ([]byte, error) {
buf := bytes.Buffer{}
buf.Grow(len(src)) // guess a size to avoid repeat allocations.
writer := writerPool.Get().(*lz4.Writer)
writer.Reset(&buf)
_, err := writer.Write(src)
if err != nil {
// don't return writer to pool on error.
return nil, err
}
err = writer.Close()
if err != nil {
// don't return writer to pool on error.
return nil, err
}
writerPool.Put(writer)
return buf.Bytes(), err
}
// Decode implements the kafka.CompressionCodec interface.
func (c CompressionCodec) Decode(src []byte) ([]byte, error) {
reader := readerPool.Get().(*lz4.Reader)
reader.Reset(bytes.NewReader(src))
res, err := ioutil.ReadAll(reader)
// only return the reader to pool if the read was a success.
if err == nil {
readerPool.Put(reader)
}
return res, err
}