hugo/common/hstrings/strings.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 hstrings
import (
"fmt"
"regexp"
"strings"
"sync"
"github.com/gohugoio/hugo/compare"
)
var _ compare.Eqer = StringEqualFold("")
// StringEqualFold is a string that implements the compare.Eqer interface and considers
// two strings equal if they are equal when folded to lower case.
// The compare.Eqer interface is used in Hugo to compare values in templates (e.g. using the eq template function).
type StringEqualFold string
func (s StringEqualFold) EqualFold(s2 string) bool {
return strings.EqualFold(string(s), s2)
}
func (s StringEqualFold) String() string {
return string(s)
}
func (s StringEqualFold) Eq(s2 any) bool {
switch ss := s2.(type) {
case string:
return s.EqualFold(ss)
case fmt.Stringer:
return s.EqualFold(ss.String())
}
return false
}
// EqualAny returns whether a string is equal to any of the given strings.
func EqualAny(a string, b ...string) bool {
for _, s := range b {
if a == s {
return true
}
}
return false
}
// regexpCache represents a cache of regexp objects protected by a mutex.
type regexpCache struct {
mu sync.RWMutex
re map[string]*regexp.Regexp
}
func (rc *regexpCache) getOrCompileRegexp(pattern string) (re *regexp.Regexp, err error) {
var ok bool
if re, ok = rc.get(pattern); !ok {
re, err = regexp.Compile(pattern)
if err != nil {
return nil, err
}
rc.set(pattern, re)
}
return re, nil
}
func (rc *regexpCache) get(key string) (re *regexp.Regexp, ok bool) {
rc.mu.RLock()
re, ok = rc.re[key]
rc.mu.RUnlock()
return
}
func (rc *regexpCache) set(key string, re *regexp.Regexp) {
rc.mu.Lock()
rc.re[key] = re
rc.mu.Unlock()
}
var reCache = regexpCache{re: make(map[string]*regexp.Regexp)}
// GetOrCompileRegexp retrieves a regexp object from the cache based upon the pattern.
// If the pattern is not found in the cache, the pattern is compiled and added to
// the cache.
func GetOrCompileRegexp(pattern string) (re *regexp.Regexp, err error) {
return reCache.getOrCompileRegexp(pattern)
}
// InSlice checks if a string is an element of a slice of strings
// and returns a boolean value.
func InSlice(arr []string, el string) bool {
for _, v := range arr {
if v == el {
return true
}
}
return false
}
// InSlicEqualFold checks if a string is an element of a slice of strings
// and returns a boolean value.
// It uses strings.EqualFold to compare.
func InSlicEqualFold(arr []string, el string) bool {
for _, v := range arr {
if strings.EqualFold(v, el) {
return true
}
}
return false
}