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https://codeberg.org/forgejo/forgejo
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9fdb4f887b
* Update to go-org 1.3.2 Fix #12727 Signed-off-by: Andrew Thornton <art27@cantab.net> * Fix unit test Signed-off-by: Andrew Thornton <art27@cantab.net> Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
355 lines
9.6 KiB
Go
Vendored
355 lines
9.6 KiB
Go
Vendored
/*
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Package regexp2 is a regexp package that has an interface similar to Go's framework regexp engine but uses a
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more feature full regex engine behind the scenes.
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It doesn't have constant time guarantees, but it allows backtracking and is compatible with Perl5 and .NET.
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You'll likely be better off with the RE2 engine from the regexp package and should only use this if you
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need to write very complex patterns or require compatibility with .NET.
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*/
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package regexp2
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import (
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"errors"
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"math"
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"strconv"
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"sync"
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"time"
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"github.com/dlclark/regexp2/syntax"
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)
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// Default timeout used when running regexp matches -- "forever"
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var DefaultMatchTimeout = time.Duration(math.MaxInt64)
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// Regexp is the representation of a compiled regular expression.
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// A Regexp is safe for concurrent use by multiple goroutines.
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type Regexp struct {
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//timeout when trying to find matches
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MatchTimeout time.Duration
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// read-only after Compile
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pattern string // as passed to Compile
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options RegexOptions // options
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caps map[int]int // capnum->index
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capnames map[string]int //capture group name -> index
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capslist []string //sorted list of capture group names
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capsize int // size of the capture array
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code *syntax.Code // compiled program
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// cache of machines for running regexp
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muRun sync.Mutex
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runner []*runner
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}
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// Compile parses a regular expression and returns, if successful,
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// a Regexp object that can be used to match against text.
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func Compile(expr string, opt RegexOptions) (*Regexp, error) {
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// parse it
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tree, err := syntax.Parse(expr, syntax.RegexOptions(opt))
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if err != nil {
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return nil, err
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}
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// translate it to code
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code, err := syntax.Write(tree)
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if err != nil {
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return nil, err
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}
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// return it
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return &Regexp{
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pattern: expr,
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options: opt,
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caps: code.Caps,
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capnames: tree.Capnames,
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capslist: tree.Caplist,
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capsize: code.Capsize,
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code: code,
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MatchTimeout: DefaultMatchTimeout,
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}, nil
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}
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// MustCompile is like Compile but panics if the expression cannot be parsed.
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// It simplifies safe initialization of global variables holding compiled regular
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// expressions.
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func MustCompile(str string, opt RegexOptions) *Regexp {
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regexp, error := Compile(str, opt)
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if error != nil {
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panic(`regexp2: Compile(` + quote(str) + `): ` + error.Error())
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}
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return regexp
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}
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// Escape adds backslashes to any special characters in the input string
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func Escape(input string) string {
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return syntax.Escape(input)
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}
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// Unescape removes any backslashes from previously-escaped special characters in the input string
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func Unescape(input string) (string, error) {
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return syntax.Unescape(input)
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}
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// String returns the source text used to compile the regular expression.
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func (re *Regexp) String() string {
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return re.pattern
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}
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func quote(s string) string {
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if strconv.CanBackquote(s) {
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return "`" + s + "`"
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}
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return strconv.Quote(s)
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}
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// RegexOptions impact the runtime and parsing behavior
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// for each specific regex. They are setable in code as well
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// as in the regex pattern itself.
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type RegexOptions int32
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const (
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None RegexOptions = 0x0
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IgnoreCase = 0x0001 // "i"
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Multiline = 0x0002 // "m"
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ExplicitCapture = 0x0004 // "n"
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Compiled = 0x0008 // "c"
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Singleline = 0x0010 // "s"
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IgnorePatternWhitespace = 0x0020 // "x"
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RightToLeft = 0x0040 // "r"
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Debug = 0x0080 // "d"
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ECMAScript = 0x0100 // "e"
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RE2 = 0x0200 // RE2 (regexp package) compatibility mode
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)
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func (re *Regexp) RightToLeft() bool {
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return re.options&RightToLeft != 0
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}
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func (re *Regexp) Debug() bool {
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return re.options&Debug != 0
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}
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// Replace searches the input string and replaces each match found with the replacement text.
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// Count will limit the number of matches attempted and startAt will allow
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// us to skip past possible matches at the start of the input (left or right depending on RightToLeft option).
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// Set startAt and count to -1 to go through the whole string
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func (re *Regexp) Replace(input, replacement string, startAt, count int) (string, error) {
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data, err := syntax.NewReplacerData(replacement, re.caps, re.capsize, re.capnames, syntax.RegexOptions(re.options))
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if err != nil {
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return "", err
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}
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//TODO: cache ReplacerData
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return replace(re, data, nil, input, startAt, count)
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}
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// ReplaceFunc searches the input string and replaces each match found using the string from the evaluator
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// Count will limit the number of matches attempted and startAt will allow
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// us to skip past possible matches at the start of the input (left or right depending on RightToLeft option).
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// Set startAt and count to -1 to go through the whole string.
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func (re *Regexp) ReplaceFunc(input string, evaluator MatchEvaluator, startAt, count int) (string, error) {
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return replace(re, nil, evaluator, input, startAt, count)
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}
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// FindStringMatch searches the input string for a Regexp match
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func (re *Regexp) FindStringMatch(s string) (*Match, error) {
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// convert string to runes
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return re.run(false, -1, getRunes(s))
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}
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// FindRunesMatch searches the input rune slice for a Regexp match
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func (re *Regexp) FindRunesMatch(r []rune) (*Match, error) {
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return re.run(false, -1, r)
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}
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// FindStringMatchStartingAt searches the input string for a Regexp match starting at the startAt index
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func (re *Regexp) FindStringMatchStartingAt(s string, startAt int) (*Match, error) {
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if startAt > len(s) {
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return nil, errors.New("startAt must be less than the length of the input string")
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}
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r, startAt := re.getRunesAndStart(s, startAt)
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if startAt == -1 {
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// we didn't find our start index in the string -- that's a problem
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return nil, errors.New("startAt must align to the start of a valid rune in the input string")
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}
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return re.run(false, startAt, r)
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}
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// FindRunesMatchStartingAt searches the input rune slice for a Regexp match starting at the startAt index
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func (re *Regexp) FindRunesMatchStartingAt(r []rune, startAt int) (*Match, error) {
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return re.run(false, startAt, r)
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}
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// FindNextMatch returns the next match in the same input string as the match parameter.
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// Will return nil if there is no next match or if given a nil match.
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func (re *Regexp) FindNextMatch(m *Match) (*Match, error) {
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if m == nil {
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return nil, nil
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}
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// If previous match was empty, advance by one before matching to prevent
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// infinite loop
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startAt := m.textpos
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if m.Length == 0 {
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if m.textpos == len(m.text) {
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return nil, nil
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}
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if re.RightToLeft() {
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startAt--
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} else {
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startAt++
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}
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}
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return re.run(false, startAt, m.text)
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}
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// MatchString return true if the string matches the regex
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// error will be set if a timeout occurs
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func (re *Regexp) MatchString(s string) (bool, error) {
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m, err := re.run(true, -1, getRunes(s))
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if err != nil {
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return false, err
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}
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return m != nil, nil
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}
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func (re *Regexp) getRunesAndStart(s string, startAt int) ([]rune, int) {
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if startAt < 0 {
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if re.RightToLeft() {
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r := getRunes(s)
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return r, len(r)
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}
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return getRunes(s), 0
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}
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ret := make([]rune, len(s))
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i := 0
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runeIdx := -1
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for strIdx, r := range s {
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if strIdx == startAt {
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runeIdx = i
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}
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ret[i] = r
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i++
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}
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if startAt == len(s) {
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runeIdx = i
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}
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return ret[:i], runeIdx
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}
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func getRunes(s string) []rune {
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return []rune(s)
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}
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// MatchRunes return true if the runes matches the regex
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// error will be set if a timeout occurs
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func (re *Regexp) MatchRunes(r []rune) (bool, error) {
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m, err := re.run(true, -1, r)
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if err != nil {
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return false, err
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}
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return m != nil, nil
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}
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// GetGroupNames Returns the set of strings used to name capturing groups in the expression.
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func (re *Regexp) GetGroupNames() []string {
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var result []string
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if re.capslist == nil {
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result = make([]string, re.capsize)
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for i := 0; i < len(result); i++ {
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result[i] = strconv.Itoa(i)
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}
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} else {
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result = make([]string, len(re.capslist))
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copy(result, re.capslist)
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}
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return result
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}
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// GetGroupNumbers returns the integer group numbers corresponding to a group name.
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func (re *Regexp) GetGroupNumbers() []int {
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var result []int
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if re.caps == nil {
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result = make([]int, re.capsize)
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for i := 0; i < len(result); i++ {
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result[i] = i
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}
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} else {
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result = make([]int, len(re.caps))
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for k, v := range re.caps {
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result[v] = k
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}
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}
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return result
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}
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// GroupNameFromNumber retrieves a group name that corresponds to a group number.
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// It will return "" for and unknown group number. Unnamed groups automatically
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// receive a name that is the decimal string equivalent of its number.
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func (re *Regexp) GroupNameFromNumber(i int) string {
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if re.capslist == nil {
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if i >= 0 && i < re.capsize {
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return strconv.Itoa(i)
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}
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return ""
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}
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if re.caps != nil {
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var ok bool
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if i, ok = re.caps[i]; !ok {
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return ""
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}
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}
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if i >= 0 && i < len(re.capslist) {
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return re.capslist[i]
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}
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return ""
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}
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// GroupNumberFromName returns a group number that corresponds to a group name.
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// Returns -1 if the name is not a recognized group name. Numbered groups
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// automatically get a group name that is the decimal string equivalent of its number.
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func (re *Regexp) GroupNumberFromName(name string) int {
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// look up name if we have a hashtable of names
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if re.capnames != nil {
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if k, ok := re.capnames[name]; ok {
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return k
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}
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return -1
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}
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// convert to an int if it looks like a number
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result := 0
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for i := 0; i < len(name); i++ {
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ch := name[i]
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if ch > '9' || ch < '0' {
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return -1
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}
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result *= 10
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result += int(ch - '0')
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}
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// return int if it's in range
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if result >= 0 && result < re.capsize {
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return result
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}
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return -1
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}
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