hugo/identity/identityhash.go

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// Copyright 2023 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 identity
import (
"strconv"
"github.com/mitchellh/hashstructure"
)
// HashString returns a hash from the given elements.
// It will panic if the hash cannot be calculated.
// Note that this hash should be used primarily for identity, not for change detection as
// it in the more complex values (e.g. Page) will not hash the full content.
func HashString(vs ...any) string {
hash := HashUint64(vs...)
return strconv.FormatUint(hash, 10)
}
// HashUint64 returns a hash from the given elements.
// It will panic if the hash cannot be calculated.
// Note that this hash should be used primarily for identity, not for change detection as
// it in the more complex values (e.g. Page) will not hash the full content.
func HashUint64(vs ...any) uint64 {
var o any
if len(vs) == 1 {
o = toHashable(vs[0])
} else {
elements := make([]any, len(vs))
for i, e := range vs {
elements[i] = toHashable(e)
}
o = elements
}
hash, err := hashstructure.Hash(o, nil)
if err != nil {
panic(err)
}
return hash
}
type keyer interface {
Key() string
}
// For structs, hashstructure.Hash only works on the exported fields,
// so rewrite the input slice for known identity types.
func toHashable(v any) any {
switch t := v.(type) {
case Provider:
return t.GetIdentity()
case keyer:
return t.Key()
default:
return v
}
}