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https://github.com/gohugoio/hugo.git
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d5eda13cb2
Note that we only use this for change detection. The previous implementation invoked `MD5FromReaderFast` that created a MD5 has from 8 64 bytes chunks in the file, which is obviously very fast. The new implementation creates the hash from the entire file and ... seems to be even more effective: ``` name old time/op new time/op delta HashImage-10 9.45µs ±21% 10.89µs ± 1% ~ (p=0.343 n=4+4) name old alloc/op new alloc/op delta HashImage-10 144B ± 0% 8B ± 0% -94.44% (p=0.029 n=4+4) name old allocs/op new allocs/op delta HashImage-10 4.00 ± 0% 1.00 ± 0% -75.00% (p=0.029 n=4+4) ```
86 lines
2 KiB
Go
86 lines
2 KiB
Go
// Copyright 2024 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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// Package hashing provides common hashing utilities.
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package hashing
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import (
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"encoding/hex"
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"io"
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"sync"
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"github.com/cespare/xxhash/v2"
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)
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// XXHashFromReader calculates the xxHash for the given reader.
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func XXHashFromReader(r io.ReadSeeker) (uint64, int64, error) {
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h := getXxHashReadFrom()
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defer putXxHashReadFrom(h)
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size, err := io.Copy(h, r)
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if err != nil {
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return 0, 0, err
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}
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return h.Sum64(), size, nil
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}
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// XXHashFromString calculates the xxHash for the given string.
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func XXHashFromString(s string) (uint64, error) {
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h := xxhash.New()
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h.WriteString(s)
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return h.Sum64(), nil
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}
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// XxHashFromStringHexEncoded calculates the xxHash for the given string
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// and returns the hash as a hex encoded string.
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func XxHashFromStringHexEncoded(f string) string {
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h := xxhash.New()
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h.WriteString(f)
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hash := h.Sum(nil)
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return hex.EncodeToString(hash)
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}
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type xxhashReadFrom struct {
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buff []byte
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*xxhash.Digest
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}
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func (x *xxhashReadFrom) ReadFrom(r io.Reader) (int64, error) {
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for {
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n, err := r.Read(x.buff)
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if n > 0 {
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x.Digest.Write(x.buff[:n])
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}
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if err != nil {
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if err == io.EOF {
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err = nil
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}
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return int64(n), err
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}
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}
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}
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var xXhashReadFromPool = sync.Pool{
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New: func() any {
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return &xxhashReadFrom{Digest: xxhash.New(), buff: make([]byte, 48*1024)}
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},
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}
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func getXxHashReadFrom() *xxhashReadFrom {
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return xXhashReadFromPool.Get().(*xxhashReadFrom)
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}
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func putXxHashReadFrom(h *xxhashReadFrom) {
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h.Reset()
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xXhashReadFromPool.Put(h)
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}
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