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Fix and optimize ETag calc

This commit is contained in:
DarthSim 2018-10-06 01:45:14 +06:00
parent d333c7ca61
commit 85d2738a72

51
etag.go
View File

@ -3,20 +3,47 @@ package main
import (
"context"
"crypto/sha256"
"encoding/binary"
"fmt"
"encoding/hex"
"encoding/json"
"hash"
"sync"
)
var notModifiedErr = newError(304, "Not modified", "Not modified")
func calcETag(ctx context.Context) []byte {
footprint := sha256.Sum256(getImageData(ctx).Bytes())
hash := sha256.New()
hash.Write(footprint[:])
hash.Write([]byte(version))
binary.Write(hash, binary.LittleEndian, conf)
binary.Write(hash, binary.LittleEndian, *getProcessingOptions(ctx))
return []byte(fmt.Sprintf("%x", hash.Sum(nil)))
type eTagCalc struct {
hash hash.Hash
enc *json.Encoder
}
var eTagCalcPool = sync.Pool{
New: func() interface{} {
h := sha256.New()
enc := json.NewEncoder(h)
enc.SetEscapeHTML(false)
enc.SetIndent("", "")
return &eTagCalc{h, enc}
},
}
func calcETag(ctx context.Context) []byte {
c := eTagCalcPool.Get().(*eTagCalc)
defer eTagCalcPool.Put(c)
c.hash.Reset()
c.hash.Write(getImageData(ctx).Bytes())
footprint := c.hash.Sum(nil)
c.hash.Reset()
c.hash.Write(footprint)
c.hash.Write([]byte(version))
c.enc.Encode(conf)
c.enc.Encode(getProcessingOptions(ctx))
etag := make([]byte, 64)
hex.Encode(etag, c.hash.Sum(nil))
return etag
}