hugo/tpl/hash/hash.go
Bjørn Erik Pedersen d5eda13cb2 Replace the MD5 hashing of images with xxHash
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)
```
2024-07-31 16:44:06 +02:00

85 lines
2.1 KiB
Go

// Copyright 2024 The Hugo Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// Package hash provides non-cryptographic hash functions for template use.
package hash
import (
"context"
"hash/fnv"
"github.com/gohugoio/hugo/common/hashing"
"github.com/gohugoio/hugo/deps"
"github.com/gohugoio/hugo/tpl/internal"
"github.com/spf13/cast"
)
// New returns a new instance of the hash-namespaced template functions.
func New() *Namespace {
return &Namespace{}
}
// Namespace provides template functions for the "hash" namespace.
type Namespace struct{}
// FNV32a hashes v using fnv32a algorithm.
func (ns *Namespace) FNV32a(v any) (int, error) {
conv, err := cast.ToStringE(v)
if err != nil {
return 0, err
}
algorithm := fnv.New32a()
algorithm.Write([]byte(conv))
return int(algorithm.Sum32()), nil
}
// XxHash returns the xxHash of the input string.
func (ns *Namespace) XxHash(v any) (string, error) {
conv, err := cast.ToStringE(v)
if err != nil {
return "", err
}
return hashing.XxHashFromStringHexEncoded(conv), nil
}
const name = "hash"
func init() {
f := func(d *deps.Deps) *internal.TemplateFuncsNamespace {
ctx := New()
ns := &internal.TemplateFuncsNamespace{
Name: name,
Context: func(cctx context.Context, args ...any) (any, error) { return ctx, nil },
}
ns.AddMethodMapping(ctx.XxHash,
[]string{"xxhash"},
[][2]string{
{`{{ hash.XxHash "The quick brown fox jumps over the lazy dog" }}`, `0b242d361fda71bc`},
},
)
ns.AddMethodMapping(ctx.FNV32a,
nil,
[][2]string{
{`{{ hash.FNV32a "Hugo Rocks!!" }}`, `1515779328`},
},
)
return ns
}
internal.AddTemplateFuncsNamespace(f)
}