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https://github.com/prometheus/prometheus.git
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2524a91591
When `zeroOrOneCharacterStringMatcher` wach checking the input string, it assumed that if there are more than one bytes, then there are more than one runes, but that's not necessarily true. Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>
959 lines
28 KiB
Go
959 lines
28 KiB
Go
// Copyright 2020 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package labels
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import (
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"slices"
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"strings"
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"unicode/utf8"
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"github.com/grafana/regexp"
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"github.com/grafana/regexp/syntax"
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)
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const (
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maxSetMatches = 256
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// The minimum number of alternate values a regex should have to trigger
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// the optimization done by optimizeEqualStringMatchers() and so use a map
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// to match values instead of iterating over a list. This value has
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// been computed running BenchmarkOptimizeEqualStringMatchers.
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minEqualMultiStringMatcherMapThreshold = 16
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)
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type FastRegexMatcher struct {
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// Under some conditions, re is nil because the expression is never parsed.
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// We store the original string to be able to return it in GetRegexString().
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reString string
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re *regexp.Regexp
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setMatches []string
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stringMatcher StringMatcher
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prefix string
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suffix string
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contains string
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// matchString is the "compiled" function to run by MatchString().
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matchString func(string) bool
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}
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func NewFastRegexMatcher(v string) (*FastRegexMatcher, error) {
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m := &FastRegexMatcher{
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reString: v,
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}
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m.stringMatcher, m.setMatches = optimizeAlternatingLiterals(v)
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if m.stringMatcher != nil {
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// If we already have a string matcher, we don't need to parse the regex
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// or compile the matchString function. This also avoids the behavior in
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// compileMatchStringFunction where it prefers to use setMatches when
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// available, even if the string matcher is faster.
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m.matchString = m.stringMatcher.Matches
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} else {
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parsed, err := syntax.Parse(v, syntax.Perl)
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if err != nil {
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return nil, err
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}
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// Simplify the syntax tree to run faster.
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parsed = parsed.Simplify()
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m.re, err = regexp.Compile("^(?:" + parsed.String() + ")$")
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if err != nil {
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return nil, err
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}
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if parsed.Op == syntax.OpConcat {
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m.prefix, m.suffix, m.contains = optimizeConcatRegex(parsed)
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}
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if matches, caseSensitive := findSetMatches(parsed); caseSensitive {
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m.setMatches = matches
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}
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m.stringMatcher = stringMatcherFromRegexp(parsed)
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m.matchString = m.compileMatchStringFunction()
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}
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return m, nil
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}
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// compileMatchStringFunction returns the function to run by MatchString().
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func (m *FastRegexMatcher) compileMatchStringFunction() func(string) bool {
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// If the only optimization available is the string matcher, then we can just run it.
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if len(m.setMatches) == 0 && m.prefix == "" && m.suffix == "" && m.contains == "" && m.stringMatcher != nil {
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return m.stringMatcher.Matches
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}
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return func(s string) bool {
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if len(m.setMatches) != 0 {
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for _, match := range m.setMatches {
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if match == s {
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return true
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}
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}
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return false
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}
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if m.prefix != "" && !strings.HasPrefix(s, m.prefix) {
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return false
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}
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if m.suffix != "" && !strings.HasSuffix(s, m.suffix) {
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return false
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}
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if m.contains != "" && !strings.Contains(s, m.contains) {
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return false
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}
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if m.stringMatcher != nil {
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return m.stringMatcher.Matches(s)
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}
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return m.re.MatchString(s)
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}
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}
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// IsOptimized returns true if any fast-path optimization is applied to the
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// regex matcher.
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func (m *FastRegexMatcher) IsOptimized() bool {
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return len(m.setMatches) > 0 || m.stringMatcher != nil || m.prefix != "" || m.suffix != "" || m.contains != ""
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}
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// findSetMatches extract equality matches from a regexp.
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// Returns nil if we can't replace the regexp by only equality matchers or the regexp contains
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// a mix of case sensitive and case insensitive matchers.
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func findSetMatches(re *syntax.Regexp) (matches []string, caseSensitive bool) {
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clearBeginEndText(re)
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return findSetMatchesInternal(re, "")
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}
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func findSetMatchesInternal(re *syntax.Regexp, base string) (matches []string, caseSensitive bool) {
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switch re.Op {
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case syntax.OpBeginText:
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// Correctly handling the begin text operator inside a regex is tricky,
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// so in this case we fallback to the regex engine.
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return nil, false
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case syntax.OpEndText:
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// Correctly handling the end text operator inside a regex is tricky,
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// so in this case we fallback to the regex engine.
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return nil, false
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case syntax.OpLiteral:
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return []string{base + string(re.Rune)}, isCaseSensitive(re)
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case syntax.OpEmptyMatch:
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if base != "" {
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return []string{base}, isCaseSensitive(re)
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}
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case syntax.OpAlternate:
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return findSetMatchesFromAlternate(re, base)
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case syntax.OpCapture:
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clearCapture(re)
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return findSetMatchesInternal(re, base)
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case syntax.OpConcat:
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return findSetMatchesFromConcat(re, base)
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case syntax.OpCharClass:
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if len(re.Rune)%2 != 0 {
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return nil, false
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}
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var matches []string
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var totalSet int
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for i := 0; i+1 < len(re.Rune); i += 2 {
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totalSet += int(re.Rune[i+1]-re.Rune[i]) + 1
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}
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// limits the total characters that can be used to create matches.
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// In some case like negation [^0-9] a lot of possibilities exists and that
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// can create thousands of possible matches at which points we're better off using regexp.
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if totalSet > maxSetMatches {
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return nil, false
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}
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for i := 0; i+1 < len(re.Rune); i += 2 {
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lo, hi := re.Rune[i], re.Rune[i+1]
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for c := lo; c <= hi; c++ {
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matches = append(matches, base+string(c))
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}
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}
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return matches, isCaseSensitive(re)
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default:
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return nil, false
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}
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return nil, false
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}
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func findSetMatchesFromConcat(re *syntax.Regexp, base string) (matches []string, matchesCaseSensitive bool) {
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if len(re.Sub) == 0 {
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return nil, false
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}
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clearCapture(re.Sub...)
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matches = []string{base}
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for i := 0; i < len(re.Sub); i++ {
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var newMatches []string
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for j, b := range matches {
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m, caseSensitive := findSetMatchesInternal(re.Sub[i], b)
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if m == nil {
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return nil, false
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}
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if tooManyMatches(newMatches, m...) {
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return nil, false
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}
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// All matches must have the same case sensitivity. If it's the first set of matches
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// returned, we store its sensitivity as the expected case, and then we'll check all
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// other ones.
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if i == 0 && j == 0 {
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matchesCaseSensitive = caseSensitive
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}
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if matchesCaseSensitive != caseSensitive {
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return nil, false
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}
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newMatches = append(newMatches, m...)
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}
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matches = newMatches
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}
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return matches, matchesCaseSensitive
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}
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func findSetMatchesFromAlternate(re *syntax.Regexp, base string) (matches []string, matchesCaseSensitive bool) {
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for i, sub := range re.Sub {
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found, caseSensitive := findSetMatchesInternal(sub, base)
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if found == nil {
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return nil, false
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}
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if tooManyMatches(matches, found...) {
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return nil, false
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}
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// All matches must have the same case sensitivity. If it's the first set of matches
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// returned, we store its sensitivity as the expected case, and then we'll check all
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// other ones.
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if i == 0 {
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matchesCaseSensitive = caseSensitive
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}
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if matchesCaseSensitive != caseSensitive {
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return nil, false
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}
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matches = append(matches, found...)
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}
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return matches, matchesCaseSensitive
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}
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// clearCapture removes capture operation as they are not used for matching.
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func clearCapture(regs ...*syntax.Regexp) {
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for _, r := range regs {
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// Iterate on the regexp because capture groups could be nested.
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for r.Op == syntax.OpCapture {
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*r = *r.Sub[0]
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}
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}
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}
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// clearBeginEndText removes the begin and end text from the regexp. Prometheus regexp are anchored to the beginning and end of the string.
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func clearBeginEndText(re *syntax.Regexp) {
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// Do not clear begin/end text from an alternate operator because it could
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// change the actual regexp properties.
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if re.Op == syntax.OpAlternate {
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return
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}
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if len(re.Sub) == 0 {
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return
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}
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if len(re.Sub) == 1 {
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if re.Sub[0].Op == syntax.OpBeginText || re.Sub[0].Op == syntax.OpEndText {
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// We need to remove this element. Since it's the only one, we convert into a matcher of an empty string.
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// OpEmptyMatch is regexp's nop operator.
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re.Op = syntax.OpEmptyMatch
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re.Sub = nil
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return
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}
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}
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if re.Sub[0].Op == syntax.OpBeginText {
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re.Sub = re.Sub[1:]
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}
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if re.Sub[len(re.Sub)-1].Op == syntax.OpEndText {
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re.Sub = re.Sub[:len(re.Sub)-1]
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}
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}
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// isCaseInsensitive tells if a regexp is case insensitive.
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// The flag should be check at each level of the syntax tree.
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func isCaseInsensitive(reg *syntax.Regexp) bool {
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return (reg.Flags & syntax.FoldCase) != 0
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}
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// isCaseSensitive tells if a regexp is case sensitive.
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// The flag should be check at each level of the syntax tree.
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func isCaseSensitive(reg *syntax.Regexp) bool {
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return !isCaseInsensitive(reg)
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}
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// tooManyMatches guards against creating too many set matches.
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func tooManyMatches(matches []string, added ...string) bool {
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return len(matches)+len(added) > maxSetMatches
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}
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func (m *FastRegexMatcher) MatchString(s string) bool {
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return m.matchString(s)
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}
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func (m *FastRegexMatcher) SetMatches() []string {
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// IMPORTANT: always return a copy, otherwise if the caller manipulate this slice it will
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// also get manipulated in the cached FastRegexMatcher instance.
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return slices.Clone(m.setMatches)
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}
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func (m *FastRegexMatcher) GetRegexString() string {
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return m.reString
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}
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// optimizeAlternatingLiterals optimizes a regex of the form
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//
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// `literal1|literal2|literal3|...`
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//
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// this function returns an optimized StringMatcher or nil if the regex
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// cannot be optimized in this way, and a list of setMatches up to maxSetMatches.
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func optimizeAlternatingLiterals(s string) (StringMatcher, []string) {
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if len(s) == 0 {
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return emptyStringMatcher{}, nil
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}
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estimatedAlternates := strings.Count(s, "|") + 1
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// If there are no alternates, check if the string is a literal
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if estimatedAlternates == 1 {
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if regexp.QuoteMeta(s) == s {
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return &equalStringMatcher{s: s, caseSensitive: true}, []string{s}
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}
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return nil, nil
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}
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multiMatcher := newEqualMultiStringMatcher(true, estimatedAlternates)
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for end := strings.IndexByte(s, '|'); end > -1; end = strings.IndexByte(s, '|') {
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// Split the string into the next literal and the remainder
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subMatch := s[:end]
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s = s[end+1:]
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// break if any of the submatches are not literals
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if regexp.QuoteMeta(subMatch) != subMatch {
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return nil, nil
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}
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multiMatcher.add(subMatch)
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}
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// break if the remainder is not a literal
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if regexp.QuoteMeta(s) != s {
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return nil, nil
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}
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multiMatcher.add(s)
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return multiMatcher, multiMatcher.setMatches()
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}
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// optimizeConcatRegex returns literal prefix/suffix text that can be safely
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// checked against the label value before running the regexp matcher.
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func optimizeConcatRegex(r *syntax.Regexp) (prefix, suffix, contains string) {
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sub := r.Sub
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// We can safely remove begin and end text matchers respectively
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// at the beginning and end of the regexp.
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if len(sub) > 0 && sub[0].Op == syntax.OpBeginText {
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sub = sub[1:]
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}
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if len(sub) > 0 && sub[len(sub)-1].Op == syntax.OpEndText {
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sub = sub[:len(sub)-1]
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}
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if len(sub) == 0 {
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return
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}
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// Given Prometheus regex matchers are always anchored to the begin/end
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// of the text, if the first/last operations are literals, we can safely
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// treat them as prefix/suffix.
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if sub[0].Op == syntax.OpLiteral && (sub[0].Flags&syntax.FoldCase) == 0 {
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prefix = string(sub[0].Rune)
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}
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if last := len(sub) - 1; sub[last].Op == syntax.OpLiteral && (sub[last].Flags&syntax.FoldCase) == 0 {
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suffix = string(sub[last].Rune)
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}
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// If contains any literal which is not a prefix/suffix, we keep the
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// 1st one. We do not keep the whole list of literals to simplify the
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// fast path.
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for i := 1; i < len(sub)-1; i++ {
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if sub[i].Op == syntax.OpLiteral && (sub[i].Flags&syntax.FoldCase) == 0 {
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contains = string(sub[i].Rune)
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break
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}
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}
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return
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}
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// StringMatcher is a matcher that matches a string in place of a regular expression.
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type StringMatcher interface {
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Matches(s string) bool
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}
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// stringMatcherFromRegexp attempts to replace a common regexp with a string matcher.
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// It returns nil if the regexp is not supported.
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func stringMatcherFromRegexp(re *syntax.Regexp) StringMatcher {
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clearBeginEndText(re)
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m := stringMatcherFromRegexpInternal(re)
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m = optimizeEqualStringMatchers(m, minEqualMultiStringMatcherMapThreshold)
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return m
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}
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func stringMatcherFromRegexpInternal(re *syntax.Regexp) StringMatcher {
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clearCapture(re)
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switch re.Op {
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case syntax.OpBeginText:
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// Correctly handling the begin text operator inside a regex is tricky,
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// so in this case we fallback to the regex engine.
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return nil
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case syntax.OpEndText:
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// Correctly handling the end text operator inside a regex is tricky,
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// so in this case we fallback to the regex engine.
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return nil
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case syntax.OpPlus:
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if re.Sub[0].Op != syntax.OpAnyChar && re.Sub[0].Op != syntax.OpAnyCharNotNL {
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return nil
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}
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return &anyNonEmptyStringMatcher{
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matchNL: re.Sub[0].Op == syntax.OpAnyChar,
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}
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case syntax.OpStar:
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if re.Sub[0].Op != syntax.OpAnyChar && re.Sub[0].Op != syntax.OpAnyCharNotNL {
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return nil
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}
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// If the newline is valid, than this matcher literally match any string (even empty).
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if re.Sub[0].Op == syntax.OpAnyChar {
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return trueMatcher{}
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}
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// Any string is fine (including an empty one), as far as it doesn't contain any newline.
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return anyStringWithoutNewlineMatcher{}
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case syntax.OpQuest:
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// Only optimize for ".?".
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if len(re.Sub) != 1 || (re.Sub[0].Op != syntax.OpAnyChar && re.Sub[0].Op != syntax.OpAnyCharNotNL) {
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return nil
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}
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return &zeroOrOneCharacterStringMatcher{
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matchNL: re.Sub[0].Op == syntax.OpAnyChar,
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}
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case syntax.OpEmptyMatch:
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return emptyStringMatcher{}
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case syntax.OpLiteral:
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return &equalStringMatcher{
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s: string(re.Rune),
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caseSensitive: !isCaseInsensitive(re),
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}
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case syntax.OpAlternate:
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or := make([]StringMatcher, 0, len(re.Sub))
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for _, sub := range re.Sub {
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m := stringMatcherFromRegexpInternal(sub)
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if m == nil {
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return nil
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}
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or = append(or, m)
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}
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return orStringMatcher(or)
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case syntax.OpConcat:
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clearCapture(re.Sub...)
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if len(re.Sub) == 0 {
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return emptyStringMatcher{}
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}
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if len(re.Sub) == 1 {
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return stringMatcherFromRegexpInternal(re.Sub[0])
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}
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var left, right StringMatcher
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// Let's try to find if there's a first and last any matchers.
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if re.Sub[0].Op == syntax.OpPlus || re.Sub[0].Op == syntax.OpStar || re.Sub[0].Op == syntax.OpQuest {
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left = stringMatcherFromRegexpInternal(re.Sub[0])
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if left == nil {
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return nil
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}
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re.Sub = re.Sub[1:]
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}
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if re.Sub[len(re.Sub)-1].Op == syntax.OpPlus || re.Sub[len(re.Sub)-1].Op == syntax.OpStar || re.Sub[len(re.Sub)-1].Op == syntax.OpQuest {
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right = stringMatcherFromRegexpInternal(re.Sub[len(re.Sub)-1])
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if right == nil {
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return nil
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}
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re.Sub = re.Sub[:len(re.Sub)-1]
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}
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matches, matchesCaseSensitive := findSetMatchesInternal(re, "")
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if len(matches) == 0 && len(re.Sub) == 2 {
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// We have not find fixed set matches. We look for other known cases that
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// we can optimize.
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switch {
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// Prefix is literal.
|
|
case right == nil && re.Sub[0].Op == syntax.OpLiteral:
|
|
right = stringMatcherFromRegexpInternal(re.Sub[1])
|
|
if right != nil {
|
|
matches = []string{string(re.Sub[0].Rune)}
|
|
matchesCaseSensitive = !isCaseInsensitive(re.Sub[0])
|
|
}
|
|
|
|
// Suffix is literal.
|
|
case left == nil && re.Sub[1].Op == syntax.OpLiteral:
|
|
left = stringMatcherFromRegexpInternal(re.Sub[0])
|
|
if left != nil {
|
|
matches = []string{string(re.Sub[1].Rune)}
|
|
matchesCaseSensitive = !isCaseInsensitive(re.Sub[1])
|
|
}
|
|
}
|
|
}
|
|
|
|
// Ensure we've found some literals to match (optionally with a left and/or right matcher).
|
|
// If not, then this optimization doesn't trigger.
|
|
if len(matches) == 0 {
|
|
return nil
|
|
}
|
|
|
|
// Use the right (and best) matcher based on what we've found.
|
|
switch {
|
|
// No left and right matchers (only fixed set matches).
|
|
case left == nil && right == nil:
|
|
// if there's no any matchers on both side it's a concat of literals
|
|
or := make([]StringMatcher, 0, len(matches))
|
|
for _, match := range matches {
|
|
or = append(or, &equalStringMatcher{
|
|
s: match,
|
|
caseSensitive: matchesCaseSensitive,
|
|
})
|
|
}
|
|
return orStringMatcher(or)
|
|
|
|
// Right matcher with 1 fixed set match.
|
|
case left == nil && len(matches) == 1:
|
|
return &literalPrefixStringMatcher{
|
|
prefix: matches[0],
|
|
prefixCaseSensitive: matchesCaseSensitive,
|
|
right: right,
|
|
}
|
|
|
|
// Left matcher with 1 fixed set match.
|
|
case right == nil && len(matches) == 1:
|
|
return &literalSuffixStringMatcher{
|
|
left: left,
|
|
suffix: matches[0],
|
|
suffixCaseSensitive: matchesCaseSensitive,
|
|
}
|
|
|
|
// We found literals in the middle. We can trigger the fast path only if
|
|
// the matches are case sensitive because containsStringMatcher doesn't
|
|
// support case insensitive.
|
|
case matchesCaseSensitive:
|
|
return &containsStringMatcher{
|
|
substrings: matches,
|
|
left: left,
|
|
right: right,
|
|
}
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// containsStringMatcher matches a string if it contains any of the substrings.
|
|
// If left and right are not nil, it's a contains operation where left and right must match.
|
|
// If left is nil, it's a hasPrefix operation and right must match.
|
|
// Finally, if right is nil it's a hasSuffix operation and left must match.
|
|
type containsStringMatcher struct {
|
|
// The matcher that must match the left side. Can be nil.
|
|
left StringMatcher
|
|
|
|
// At least one of these strings must match in the "middle", between left and right matchers.
|
|
substrings []string
|
|
|
|
// The matcher that must match the right side. Can be nil.
|
|
right StringMatcher
|
|
}
|
|
|
|
func (m *containsStringMatcher) Matches(s string) bool {
|
|
for _, substr := range m.substrings {
|
|
switch {
|
|
case m.right != nil && m.left != nil:
|
|
searchStartPos := 0
|
|
|
|
for {
|
|
pos := strings.Index(s[searchStartPos:], substr)
|
|
if pos < 0 {
|
|
break
|
|
}
|
|
|
|
// Since we started searching from searchStartPos, we have to add that offset
|
|
// to get the actual position of the substring inside the text.
|
|
pos += searchStartPos
|
|
|
|
// If both the left and right matchers match, then we can stop searching because
|
|
// we've found a match.
|
|
if m.left.Matches(s[:pos]) && m.right.Matches(s[pos+len(substr):]) {
|
|
return true
|
|
}
|
|
|
|
// Continue searching for another occurrence of the substring inside the text.
|
|
searchStartPos = pos + 1
|
|
}
|
|
case m.left != nil:
|
|
// If we have to check for characters on the left then we need to match a suffix.
|
|
if strings.HasSuffix(s, substr) && m.left.Matches(s[:len(s)-len(substr)]) {
|
|
return true
|
|
}
|
|
case m.right != nil:
|
|
if strings.HasPrefix(s, substr) && m.right.Matches(s[len(substr):]) {
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// literalPrefixStringMatcher matches a string with the given literal prefix and right side matcher.
|
|
type literalPrefixStringMatcher struct {
|
|
prefix string
|
|
prefixCaseSensitive bool
|
|
|
|
// The matcher that must match the right side. Can be nil.
|
|
right StringMatcher
|
|
}
|
|
|
|
func (m *literalPrefixStringMatcher) Matches(s string) bool {
|
|
// Ensure the prefix matches.
|
|
if m.prefixCaseSensitive && !strings.HasPrefix(s, m.prefix) {
|
|
return false
|
|
}
|
|
if !m.prefixCaseSensitive && !hasPrefixCaseInsensitive(s, m.prefix) {
|
|
return false
|
|
}
|
|
|
|
// Ensure the right side matches.
|
|
return m.right.Matches(s[len(m.prefix):])
|
|
}
|
|
|
|
// literalSuffixStringMatcher matches a string with the given literal suffix and left side matcher.
|
|
type literalSuffixStringMatcher struct {
|
|
// The matcher that must match the left side. Can be nil.
|
|
left StringMatcher
|
|
|
|
suffix string
|
|
suffixCaseSensitive bool
|
|
}
|
|
|
|
func (m *literalSuffixStringMatcher) Matches(s string) bool {
|
|
// Ensure the suffix matches.
|
|
if m.suffixCaseSensitive && !strings.HasSuffix(s, m.suffix) {
|
|
return false
|
|
}
|
|
if !m.suffixCaseSensitive && !hasSuffixCaseInsensitive(s, m.suffix) {
|
|
return false
|
|
}
|
|
|
|
// Ensure the left side matches.
|
|
return m.left.Matches(s[:len(s)-len(m.suffix)])
|
|
}
|
|
|
|
// emptyStringMatcher matches an empty string.
|
|
type emptyStringMatcher struct{}
|
|
|
|
func (m emptyStringMatcher) Matches(s string) bool {
|
|
return len(s) == 0
|
|
}
|
|
|
|
// orStringMatcher matches any of the sub-matchers.
|
|
type orStringMatcher []StringMatcher
|
|
|
|
func (m orStringMatcher) Matches(s string) bool {
|
|
for _, matcher := range m {
|
|
if matcher.Matches(s) {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// equalStringMatcher matches a string exactly and support case insensitive.
|
|
type equalStringMatcher struct {
|
|
s string
|
|
caseSensitive bool
|
|
}
|
|
|
|
func (m *equalStringMatcher) Matches(s string) bool {
|
|
if m.caseSensitive {
|
|
return m.s == s
|
|
}
|
|
return strings.EqualFold(m.s, s)
|
|
}
|
|
|
|
type multiStringMatcherBuilder interface {
|
|
StringMatcher
|
|
add(s string)
|
|
setMatches() []string
|
|
}
|
|
|
|
func newEqualMultiStringMatcher(caseSensitive bool, estimatedSize int) multiStringMatcherBuilder {
|
|
// If the estimated size is low enough, it's faster to use a slice instead of a map.
|
|
if estimatedSize < minEqualMultiStringMatcherMapThreshold {
|
|
return &equalMultiStringSliceMatcher{caseSensitive: caseSensitive, values: make([]string, 0, estimatedSize)}
|
|
}
|
|
|
|
return &equalMultiStringMapMatcher{
|
|
values: make(map[string]struct{}, estimatedSize),
|
|
caseSensitive: caseSensitive,
|
|
}
|
|
}
|
|
|
|
// equalMultiStringSliceMatcher matches a string exactly against a slice of valid values.
|
|
type equalMultiStringSliceMatcher struct {
|
|
values []string
|
|
|
|
caseSensitive bool
|
|
}
|
|
|
|
func (m *equalMultiStringSliceMatcher) add(s string) {
|
|
m.values = append(m.values, s)
|
|
}
|
|
|
|
func (m *equalMultiStringSliceMatcher) setMatches() []string {
|
|
return m.values
|
|
}
|
|
|
|
func (m *equalMultiStringSliceMatcher) Matches(s string) bool {
|
|
if m.caseSensitive {
|
|
for _, v := range m.values {
|
|
if s == v {
|
|
return true
|
|
}
|
|
}
|
|
} else {
|
|
for _, v := range m.values {
|
|
if strings.EqualFold(s, v) {
|
|
return true
|
|
}
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// equalMultiStringMapMatcher matches a string exactly against a map of valid values.
|
|
type equalMultiStringMapMatcher struct {
|
|
// values contains values to match a string against. If the matching is case insensitive,
|
|
// the values here must be lowercase.
|
|
values map[string]struct{}
|
|
|
|
caseSensitive bool
|
|
}
|
|
|
|
func (m *equalMultiStringMapMatcher) add(s string) {
|
|
if !m.caseSensitive {
|
|
s = strings.ToLower(s)
|
|
}
|
|
|
|
m.values[s] = struct{}{}
|
|
}
|
|
|
|
func (m *equalMultiStringMapMatcher) setMatches() []string {
|
|
if len(m.values) >= maxSetMatches {
|
|
return nil
|
|
}
|
|
|
|
matches := make([]string, 0, len(m.values))
|
|
for s := range m.values {
|
|
matches = append(matches, s)
|
|
}
|
|
return matches
|
|
}
|
|
|
|
func (m *equalMultiStringMapMatcher) Matches(s string) bool {
|
|
if !m.caseSensitive {
|
|
s = strings.ToLower(s)
|
|
}
|
|
|
|
_, ok := m.values[s]
|
|
return ok
|
|
}
|
|
|
|
// anyStringWithoutNewlineMatcher is a stringMatcher which matches any string
|
|
// (including an empty one) as far as it doesn't contain any newline character.
|
|
type anyStringWithoutNewlineMatcher struct{}
|
|
|
|
func (m anyStringWithoutNewlineMatcher) Matches(s string) bool {
|
|
// We need to make sure it doesn't contain a newline. Since the newline is
|
|
// an ASCII character, we can use strings.IndexByte().
|
|
return strings.IndexByte(s, '\n') == -1
|
|
}
|
|
|
|
// anyNonEmptyStringMatcher is a stringMatcher which matches any non-empty string.
|
|
type anyNonEmptyStringMatcher struct {
|
|
matchNL bool
|
|
}
|
|
|
|
func (m *anyNonEmptyStringMatcher) Matches(s string) bool {
|
|
if m.matchNL {
|
|
// It's OK if the string contains a newline so we just need to make
|
|
// sure it's non-empty.
|
|
return len(s) > 0
|
|
}
|
|
|
|
// We need to make sure it non-empty and doesn't contain a newline.
|
|
// Since the newline is an ASCII character, we can use strings.IndexByte().
|
|
return len(s) > 0 && strings.IndexByte(s, '\n') == -1
|
|
}
|
|
|
|
// zeroOrOneCharacterStringMatcher is a StringMatcher which matches zero or one occurrence
|
|
// of any character. The newline character is matches only if matchNL is set to true.
|
|
type zeroOrOneCharacterStringMatcher struct {
|
|
matchNL bool
|
|
}
|
|
|
|
func (m *zeroOrOneCharacterStringMatcher) Matches(s string) bool {
|
|
if moreThanOneRune(s) {
|
|
return false
|
|
}
|
|
|
|
// No need to check for the newline if the string is empty or matching a newline is OK.
|
|
if m.matchNL || len(s) == 0 {
|
|
return true
|
|
}
|
|
|
|
return s[0] != '\n'
|
|
}
|
|
|
|
// moreThanOneRune returns true if there are more than one runes in the string.
|
|
// It doesn't check whether the string is valid UTF-8.
|
|
// The return value should be always equal to utf8.RuneCountInString(s) > 1,
|
|
// but the function is optimized for the common case where the string prefix is ASCII.
|
|
func moreThanOneRune(s string) bool {
|
|
// If len(s) is exactly one or zero, there can't be more than one rune.
|
|
// Exit through this path quickly.
|
|
if len(s) <= 1 {
|
|
return false
|
|
}
|
|
|
|
// There's one or more bytes:
|
|
// If first byte is ASCII then there are multiple runes if there are more bytes after that.
|
|
if s[0] < utf8.RuneSelf {
|
|
return len(s) > 1
|
|
}
|
|
|
|
// Less common case: first is a multibyte rune.
|
|
return utf8.RuneCountInString(s) > 1
|
|
}
|
|
|
|
// trueMatcher is a stringMatcher which matches any string (always returns true).
|
|
type trueMatcher struct{}
|
|
|
|
func (m trueMatcher) Matches(_ string) bool {
|
|
return true
|
|
}
|
|
|
|
// optimizeEqualStringMatchers optimize a specific case where all matchers are made by an
|
|
// alternation (orStringMatcher) of strings checked for equality (equalStringMatcher). In
|
|
// this specific case, when we have many strings to match against we can use a map instead
|
|
// of iterating over the list of strings.
|
|
func optimizeEqualStringMatchers(input StringMatcher, threshold int) StringMatcher {
|
|
var (
|
|
caseSensitive bool
|
|
caseSensitiveSet bool
|
|
numValues int
|
|
)
|
|
|
|
// Analyse the input StringMatcher to count the number of occurrences
|
|
// and ensure all of them have the same case sensitivity.
|
|
analyseCallback := func(matcher *equalStringMatcher) bool {
|
|
// Ensure we don't have mixed case sensitivity.
|
|
if caseSensitiveSet && caseSensitive != matcher.caseSensitive {
|
|
return false
|
|
} else if !caseSensitiveSet {
|
|
caseSensitive = matcher.caseSensitive
|
|
caseSensitiveSet = true
|
|
}
|
|
|
|
numValues++
|
|
return true
|
|
}
|
|
|
|
if !findEqualStringMatchers(input, analyseCallback) {
|
|
return input
|
|
}
|
|
|
|
// If the number of values found is less than the threshold, then we should skip the optimization.
|
|
if numValues < threshold {
|
|
return input
|
|
}
|
|
|
|
// Parse again the input StringMatcher to extract all values and storing them.
|
|
// We can skip the case sensitivity check because we've already checked it and
|
|
// if the code reach this point then it means all matchers have the same case sensitivity.
|
|
multiMatcher := newEqualMultiStringMatcher(caseSensitive, numValues)
|
|
|
|
// Ignore the return value because we already iterated over the input StringMatcher
|
|
// and it was all good.
|
|
findEqualStringMatchers(input, func(matcher *equalStringMatcher) bool {
|
|
multiMatcher.add(matcher.s)
|
|
return true
|
|
})
|
|
|
|
return multiMatcher
|
|
}
|
|
|
|
// findEqualStringMatchers analyze the input StringMatcher and calls the callback for each
|
|
// equalStringMatcher found. Returns true if and only if the input StringMatcher is *only*
|
|
// composed by an alternation of equalStringMatcher.
|
|
func findEqualStringMatchers(input StringMatcher, callback func(matcher *equalStringMatcher) bool) bool {
|
|
orInput, ok := input.(orStringMatcher)
|
|
if !ok {
|
|
return false
|
|
}
|
|
|
|
for _, m := range orInput {
|
|
switch casted := m.(type) {
|
|
case orStringMatcher:
|
|
if !findEqualStringMatchers(m, callback) {
|
|
return false
|
|
}
|
|
|
|
case *equalStringMatcher:
|
|
if !callback(casted) {
|
|
return false
|
|
}
|
|
|
|
default:
|
|
// It's not an equal string matcher, so we have to stop searching
|
|
// cause this optimization can't be applied.
|
|
return false
|
|
}
|
|
}
|
|
|
|
return true
|
|
}
|
|
|
|
func hasPrefixCaseInsensitive(s, prefix string) bool {
|
|
return len(s) >= len(prefix) && strings.EqualFold(s[0:len(prefix)], prefix)
|
|
}
|
|
|
|
func hasSuffixCaseInsensitive(s, suffix string) bool {
|
|
return len(s) >= len(suffix) && strings.EqualFold(s[len(s)-len(suffix):], suffix)
|
|
}
|