| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package matcher |
| 4 | |
| 5 | type ( |
| 6 | trueMatcher struct{} |
| 7 | falseMatcher struct{} |
| 8 | andMatcher struct{ lhs, rhs Matcher } |
| 9 | orMatcher struct{ lhs, rhs Matcher } |
| 10 | negMatcher struct{ Matcher } |
| 11 | ) |
| 12 | |
| 13 | var ( |
| 14 | matcherT trueMatcher |
| 15 | matcherF falseMatcher |
| 16 | ) |
| 17 | |
| 18 | // TRUE returns a matcher which always returns true |
| 19 | func TRUE() Matcher { |
| 20 | return matcherT |
| 21 | } |
| 22 | |
| 23 | // FALSE returns a matcher which always returns false |
| 24 | func FALSE() Matcher { |
| 25 | return matcherF |
| 26 | } |
| 27 | |
| 28 | // Not returns a matcher which positive the sub-matcher's result |
| 29 | func Not(m Matcher) Matcher { |
| 30 | switch m { |
| 31 | case TRUE(): |
| 32 | return FALSE() |
| 33 | case FALSE(): |
| 34 | return TRUE() |
| 35 | default: |
| 36 | return negMatcher{m} |
| 37 | } |
| 38 | } |
| 39 | |
| 40 | // And returns a matcher which returns true only if all of it's sub-matcher return true |
| 41 | func And(lhs, rhs Matcher, others ...Matcher) Matcher { |
| 42 | var matcher Matcher |
| 43 | switch lhs { |
| 44 | case TRUE(): |
| 45 | matcher = rhs |
| 46 | case FALSE(): |
| 47 | matcher = FALSE() |
| 48 | default: |
| 49 | switch rhs { |
| 50 | case TRUE(): |
| 51 | matcher = lhs |
| 52 | case FALSE(): |
| 53 | matcher = FALSE() |
| 54 | default: |
| 55 | matcher = andMatcher{lhs, rhs} |
| 56 | } |
| 57 | } |
| 58 | if len(others) > 0 { |
| 59 | return And(matcher, others[0], others[1:]...) |
| 60 | } |
| 61 | return matcher |
| 62 | } |
| 63 | |
| 64 | // Or returns a matcher which returns true if any of it's sub-matcher return true |
| 65 | func Or(lhs, rhs Matcher, others ...Matcher) Matcher { |
| 66 | var matcher Matcher |
| 67 | switch lhs { |
| 68 | case TRUE(): |
| 69 | matcher = TRUE() |
| 70 | case FALSE(): |
| 71 | matcher = rhs |
| 72 | default: |
| 73 | switch rhs { |
| 74 | case TRUE(): |
| 75 | matcher = TRUE() |
| 76 | case FALSE(): |
| 77 | matcher = lhs |
| 78 | default: |
| 79 | matcher = orMatcher{lhs, rhs} |
| 80 | } |
| 81 | } |
| 82 | if len(others) > 0 { |
| 83 | return Or(matcher, others[0], others[1:]...) |
| 84 | } |
| 85 | return matcher |
| 86 | } |
| 87 | |
| 88 | func (trueMatcher) Match(_ []byte) bool { return true } |
| 89 | func (trueMatcher) MatchString(_ string) bool { return true } |
| 90 | |
| 91 | func (falseMatcher) Match(_ []byte) bool { return false } |
| 92 | func (falseMatcher) MatchString(_ string) bool { return false } |
| 93 | |
| 94 | func (m andMatcher) Match(b []byte) bool { return m.lhs.Match(b) && m.rhs.Match(b) } |
| 95 | func (m andMatcher) MatchString(s string) bool { return m.lhs.MatchString(s) && m.rhs.MatchString(s) } |
| 96 | |
| 97 | func (m orMatcher) Match(b []byte) bool { return m.lhs.Match(b) || m.rhs.Match(b) } |
| 98 | func (m orMatcher) MatchString(s string) bool { return m.lhs.MatchString(s) || m.rhs.MatchString(s) } |
| 99 | |
| 100 | func (m negMatcher) Match(b []byte) bool { return !m.Matcher.Match(b) } |
| 101 | func (m negMatcher) MatchString(s string) bool { return !m.Matcher.MatchString(s) } |