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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package lazyregexp is a thin wrapper over regexp, allowing the use of global
// regexp variables without forcing them to be compiled at init.
package lazyregexp
import (
"os"
"regexp"
"strings"
"sync"
)
// Regexp is a wrapper around regexp.Regexp, where the underlying regexp will be
// compiled the first time it is needed.
type Regexp struct {
str string
once sync.Once
rx *regexp.Regexp
}
func (r *Regexp) re() *regexp.Regexp {
r.once.Do(r.build)
return r.rx
}
func (r *Regexp) build() {
r.rx = regexp.MustCompile(r.str)
r.str = ""
}
func (r *Regexp) FindSubmatch(s []byte) [][]byte {
return r.re().FindSubmatch(s)
}
func (r *Regexp) FindStringSubmatch(s string) []string {
return r.re().FindStringSubmatch(s)
}
func (r *Regexp) FindStringSubmatchIndex(s string) []int {
return r.re().FindStringSubmatchIndex(s)
}
func (r *Regexp) ReplaceAllString(src, repl string) string {
return r.re().ReplaceAllString(src, repl)
}
func (r *Regexp) FindString(s string) string {
return r.re().FindString(s)
}
func (r *Regexp) FindAllString(s string, n int) []string {
return r.re().FindAllString(s, n)
}
func (r *Regexp) MatchString(s string) bool {
return r.re().MatchString(s)
}
func (r *Regexp) SubexpNames() []string {
return r.re().SubexpNames()
}
var inTest = len(os.Args) > 0 && strings.HasSuffix(strings.TrimSuffix(os.Args[0], ".exe"), ".test")
// New creates a new lazy regexp, delaying the compiling work until it is first
// needed. If the code is being run as part of tests, the regexp compiling will
// happen immediately.
func New(str string) *Regexp {
lr := &Regexp{str: str}
if inTest {
// In tests, always compile the regexps early.
lr.re()
}
return lr
}