| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package matcher |
| 4 | |
| 5 | import "regexp" |
| 6 | |
| 7 | // NewRegExpMatcher create new matcher with RegExp format |
| 8 | func NewRegExpMatcher(expr string) (Matcher, error) { |
| 9 | switch expr { |
| 10 | case "", "^", "$": |
| 11 | return TRUE(), nil |
| 12 | case "^$", "$^": |
| 13 | return NewStringMatcher("", true, true) |
| 14 | } |
| 15 | size := len(expr) |
| 16 | chars := []rune(expr) |
| 17 | var startWith, endWith bool |
| 18 | startIdx := 0 |
| 19 | endIdx := size - 1 |
| 20 | if chars[startIdx] == '^' { |
| 21 | startWith = true |
| 22 | startIdx = 1 |
| 23 | } |
| 24 | if chars[endIdx] == '$' { |
| 25 | endWith = true |
| 26 | endIdx-- |
| 27 | } |
| 28 | |
| 29 | unescapedExpr := make([]rune, 0, endIdx-startIdx+1) |
| 30 | for i := startIdx; i <= endIdx; i++ { |
| 31 | ch := chars[i] |
| 32 | if ch == '\\' { |
| 33 | if i == endIdx { // end with '\' => invalid format |
| 34 | return regexp.Compile(expr) |
| 35 | } |
| 36 | nextCh := chars[i+1] |
| 37 | if !isRegExpMeta(nextCh) { // '\' + mon-meta char => special meaning |
| 38 | return regexp.Compile(expr) |
| 39 | } |
| 40 | unescapedExpr = append(unescapedExpr, nextCh) |
| 41 | i++ |
| 42 | } else if isRegExpMeta(ch) { |
| 43 | return regexp.Compile(expr) |
| 44 | } else { |
| 45 | unescapedExpr = append(unescapedExpr, ch) |
| 46 | } |
| 47 | } |
| 48 | |
| 49 | return NewStringMatcher(string(unescapedExpr), startWith, endWith) |
| 50 | } |
| 51 | |
| 52 | // isRegExpMeta reports whether byte b needs to be escaped by QuoteMeta. |
| 53 | func isRegExpMeta(b rune) bool { |
| 54 | switch b { |
| 55 | case '\\', '.', '+', '*', '?', '(', ')', '|', '[', ']', '{', '}', '^', '$': |
| 56 | return true |
| 57 | default: |
| 58 | return false |
| 59 | } |
| 60 | } |