1// Copyright 2018 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5// Package lazyregexp is a thin wrapper over regexp, allowing the use of global 6// regexp variables without forcing them to be compiled at init. 7package lazyregexp 8 9import ( 10 "os" 11 "regexp" 12 "strings" 13 "sync" 14) 15 16// Regexp is a wrapper around regexp.Regexp, where the underlying regexp will be 17// compiled the first time it is needed. 18type Regexp struct { 19 str string 20 once sync.Once 21 rx *regexp.Regexp 22} 23 24func (r *Regexp) re() *regexp.Regexp { 25 r.once.Do(r.build) 26 return r.rx 27} 28 29func (r *Regexp) build() { 30 r.rx = regexp.MustCompile(r.str) 31 r.str = "" 32} 33 34func (r *Regexp) FindSubmatch(s []byte) [][]byte { 35 return r.re().FindSubmatch(s) 36} 37 38func (r *Regexp) FindStringSubmatch(s string) []string { 39 return r.re().FindStringSubmatch(s) 40} 41 42func (r *Regexp) FindStringSubmatchIndex(s string) []int { 43 return r.re().FindStringSubmatchIndex(s) 44} 45 46func (r *Regexp) ReplaceAllString(src, repl string) string { 47 return r.re().ReplaceAllString(src, repl) 48} 49 50func (r *Regexp) FindString(s string) string { 51 return r.re().FindString(s) 52} 53 54func (r *Regexp) FindAllString(s string, n int) []string { 55 return r.re().FindAllString(s, n) 56} 57 58func (r *Regexp) MatchString(s string) bool { 59 return r.re().MatchString(s) 60} 61 62func (r *Regexp) SubexpNames() []string { 63 return r.re().SubexpNames() 64} 65 66var inTest = len(os.Args) > 0 && strings.HasSuffix(strings.TrimSuffix(os.Args[0], ".exe"), ".test") 67 68// New creates a new lazy regexp, delaying the compiling work until it is first 69// needed. If the code is being run as part of tests, the regexp compiling will 70// happen immediately. 71func New(str string) *Regexp { 72 lr := &Regexp{str: str} 73 if inTest { 74 // In tests, always compile the regexps early. 75 lr.re() 76 } 77 return lr 78} 79