| 1 | package chroma
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| 2 |
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| 3 | import (
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| 4 | "fmt"
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| 5 | "os"
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| 6 | "path/filepath"
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| 7 | "regexp"
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| 8 | "sort"
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| 9 | "strings"
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| 10 | "sync"
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| 11 | "time"
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| 12 | "unicode/utf8"
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| 13 |
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| 14 | "github.com/dlclark/regexp2"
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| 15 | )
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| 16 |
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| 17 | // A Rule is the fundamental matching unit of the Regex lexer state machine.
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| 18 | type Rule struct {
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| 19 | Pattern string
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| 20 | Type Emitter
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| 21 | Mutator Mutator
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| 22 | }
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| 23 |
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| 24 | // Words creates a regex that matches any of the given literal words.
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| 25 | func Words(prefix, suffix string, words ...string) string {
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| 26 | sort.Slice(words, func(i, j int) bool {
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| 27 | return len(words[j]) < len(words[i])
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| 28 | })
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| 29 | for i, word := range words {
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| 30 | words[i] = regexp.QuoteMeta(word)
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| 31 | }
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| 32 | return prefix + `(` + strings.Join(words, `|`) + `)` + suffix
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| 33 | }
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| 34 |
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| 35 | // Tokenise text using lexer, returning tokens as a slice.
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| 36 | func Tokenise(lexer Lexer, options *TokeniseOptions, text string) ([]Token, error) {
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| 37 | var out []Token
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| 38 | it, err := lexer.Tokenise(options, text)
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| 39 | if err != nil {
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| 40 | return nil, err
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| 41 | }
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| 42 | for t := it(); t != EOF; t = it() {
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| 43 | out = append(out, t)
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| 44 | }
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| 45 | return out, nil
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| 46 | }
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| 47 |
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| 48 | // Rules maps from state to a sequence of Rules.
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| 49 | type Rules map[string][]Rule
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| 50 |
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| 51 | // Rename clones rules then a rule.
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| 52 | func (r Rules) Rename(oldRule, newRule string) Rules {
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| 53 | r = r.Clone()
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| 54 | r[newRule] = r[oldRule]
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| 55 | delete(r, oldRule)
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| 56 | return r
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| 57 | }
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| 58 |
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| 59 | // Clone returns a clone of the Rules.
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| 60 | func (r Rules) Clone() Rules {
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| 61 | out := map[string][]Rule{}
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| 62 | for key, rules := range r {
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| 63 | out[key] = make([]Rule, len(rules))
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| 64 | copy(out[key], rules)
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| 65 | }
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| 66 | return out
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| 67 | }
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| 68 |
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| 69 | // Merge creates a clone of "r" then merges "rules" into the clone.
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| 70 | func (r Rules) Merge(rules Rules) Rules {
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| 71 | out := r.Clone()
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| 72 | for k, v := range rules.Clone() {
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| 73 | out[k] = v
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| 74 | }
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| 75 | return out
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| 76 | }
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| 77 |
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| 78 | // MustNewLexer creates a new Lexer with deferred rules generation or panics.
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| 79 | func MustNewLexer(config *Config, rulesFunc func() Rules) *RegexLexer {
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| 80 | lexer, err := NewLexer(config, rulesFunc)
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| 81 | if err != nil {
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| 82 | panic(err)
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| 83 | }
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| 84 | return lexer
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| 85 | }
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| 86 |
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| 87 | // NewLexer creates a new regex-based Lexer.
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| 88 | //
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| 89 | // "rules" is a state machine transition map. Each key is a state. Values are sets of rules
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| 90 | // that match input, optionally modify lexer state, and output tokens.
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| 91 | func NewLexer(config *Config, rulesFunc func() Rules) (*RegexLexer, error) {
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| 92 | if config == nil {
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| 93 | config = &Config{}
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| 94 | }
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| 95 | for _, glob := range append(config.Filenames, config.AliasFilenames...) {
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| 96 | _, err := filepath.Match(glob, "")
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| 97 | if err != nil {
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| 98 | return nil, fmt.Errorf("%s: %q is not a valid glob: %w", config.Name, glob, err)
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| 99 | }
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| 100 | }
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| 101 | r := &RegexLexer{
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| 102 | config: config,
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| 103 | fetchRulesFunc: func() (Rules, error) { return rulesFunc(), nil },
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| 104 | }
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| 105 | // One-off code to generate XML lexers in the Chroma source tree.
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| 106 | // var nameCleanRe = regexp.MustCompile(`[^-+A-Za-z0-9_]`)
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| 107 | // name := strings.ToLower(nameCleanRe.ReplaceAllString(config.Name, "_"))
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| 108 | // data, err := Marshal(r)
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| 109 | // if err != nil {
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| 110 | // if errors.Is(err, ErrNotSerialisable) {
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| 111 | // fmt.Fprintf(os.Stderr, "warning: %q: %s\n", name, err)
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| 112 | // return r, nil
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| 113 | // }
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| 114 | // return nil, err
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| 115 | // }
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| 116 | // _, file, _, ok := runtime.Caller(2)
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| 117 | // if !ok {
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| 118 | // panic("??")
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| 119 | // }
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| 120 | // fmt.Println(file)
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| 121 | // if strings.Contains(file, "/lexers/") {
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| 122 | // dir := filepath.Join(filepath.Dir(file), "embedded")
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| 123 | // err = os.MkdirAll(dir, 0700)
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| 124 | // if err != nil {
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| 125 | // return nil, err
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| 126 | // }
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| 127 | // filename := filepath.Join(dir, name) + ".xml"
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| 128 | // fmt.Println(filename)
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| 129 | // err = ioutil.WriteFile(filename, data, 0600)
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| 130 | // if err != nil {
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| 131 | // return nil, err
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| 132 | // }
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| 133 | // }
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| 134 | return r, nil
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| 135 | }
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| 136 |
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| 137 | // Trace enables debug tracing.
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| 138 | func (r *RegexLexer) Trace(trace bool) *RegexLexer {
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| 139 | r.trace = trace
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| 140 | return r
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| 141 | }
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| 142 |
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| 143 | // A CompiledRule is a Rule with a pre-compiled regex.
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| 144 | //
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| 145 | // Note that regular expressions are lazily compiled on first use of the lexer.
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| 146 | type CompiledRule struct {
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| 147 | Rule
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| 148 | Regexp *regexp2.Regexp
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| 149 | flags string
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| 150 | }
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| 151 |
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| 152 | // CompiledRules is a map of rule name to sequence of compiled rules in that rule.
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| 153 | type CompiledRules map[string][]*CompiledRule
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| 154 |
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| 155 | // LexerState contains the state for a single lex.
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| 156 | type LexerState struct {
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| 157 | Lexer *RegexLexer
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| 158 | Registry *LexerRegistry
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| 159 | Text []rune
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| 160 | Pos int
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| 161 | Rules CompiledRules
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| 162 | Stack []string
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| 163 | State string
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| 164 | Rule int
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| 165 | // Group matches.
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| 166 | Groups []string
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| 167 | // Named Group matches.
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| 168 | NamedGroups map[string]string
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| 169 | // Custum context for mutators.
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| 170 | MutatorContext map[interface{}]interface{}
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| 171 | iteratorStack []Iterator
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| 172 | options *TokeniseOptions
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| 173 | newlineAdded bool
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| 174 | }
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| 175 |
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| 176 | // Set mutator context.
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| 177 | func (l *LexerState) Set(key interface{}, value interface{}) {
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| 178 | l.MutatorContext[key] = value
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| 179 | }
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| 180 |
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| 181 | // Get mutator context.
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| 182 | func (l *LexerState) Get(key interface{}) interface{} {
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| 183 | return l.MutatorContext[key]
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| 184 | }
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| 185 |
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| 186 | // Iterator returns the next Token from the lexer.
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| 187 | func (l *LexerState) Iterator() Token { // nolint: gocognit
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| 188 | end := len(l.Text)
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| 189 | if l.newlineAdded {
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| 190 | end--
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| 191 | }
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| 192 | for l.Pos < end && len(l.Stack) > 0 {
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| 193 | // Exhaust the iterator stack, if any.
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| 194 | for len(l.iteratorStack) > 0 {
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| 195 | n := len(l.iteratorStack) - 1
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| 196 | t := l.iteratorStack[n]()
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| 197 | if t == EOF {
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| 198 | l.iteratorStack = l.iteratorStack[:n]
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| 199 | continue
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| 200 | }
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| 201 | return t
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| 202 | }
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| 203 |
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| 204 | l.State = l.Stack[len(l.Stack)-1]
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| 205 | if l.Lexer.trace {
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| 206 | fmt.Fprintf(os.Stderr, "%s: pos=%d, text=%q\n", l.State, l.Pos, string(l.Text[l.Pos:]))
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| 207 | }
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| 208 | selectedRule, ok := l.Rules[l.State]
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| 209 | if !ok {
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| 210 | panic("unknown state " + l.State)
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| 211 | }
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| 212 | ruleIndex, rule, groups, namedGroups := matchRules(l.Text, l.Pos, selectedRule)
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| 213 | // No match.
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| 214 | if groups == nil {
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| 215 | // From Pygments :\
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| 216 | //
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| 217 | // If the RegexLexer encounters a newline that is flagged as an error token, the stack is
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| 218 | // emptied and the lexer continues scanning in the 'root' state. This can help producing
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| 219 | // error-tolerant highlighting for erroneous input, e.g. when a single-line string is not
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| 220 | // closed.
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| 221 | if l.Text[l.Pos] == '\n' && l.State != l.options.State {
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| 222 | l.Stack = []string{l.options.State}
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| 223 | continue
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| 224 | }
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| 225 | l.Pos++
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| 226 | return Token{Error, string(l.Text[l.Pos-1 : l.Pos])}
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| 227 | }
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| 228 | l.Rule = ruleIndex
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| 229 | l.Groups = groups
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| 230 | l.NamedGroups = namedGroups
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| 231 | l.Pos += utf8.RuneCountInString(groups[0])
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| 232 | if rule.Mutator != nil {
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| 233 | if err := rule.Mutator.Mutate(l); err != nil {
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| 234 | panic(err)
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| 235 | }
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| 236 | }
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| 237 | if rule.Type != nil {
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| 238 | l.iteratorStack = append(l.iteratorStack, rule.Type.Emit(l.Groups, l))
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| 239 | }
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| 240 | }
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| 241 | // Exhaust the IteratorStack, if any.
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| 242 | // Duplicate code, but eh.
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| 243 | for len(l.iteratorStack) > 0 {
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| 244 | n := len(l.iteratorStack) - 1
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| 245 | t := l.iteratorStack[n]()
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| 246 | if t == EOF {
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| 247 | l.iteratorStack = l.iteratorStack[:n]
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| 248 | continue
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| 249 | }
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| 250 | return t
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| 251 | }
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| 252 |
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| 253 | // If we get to here and we still have text, return it as an error.
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| 254 | if l.Pos != len(l.Text) && len(l.Stack) == 0 {
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| 255 | value := string(l.Text[l.Pos:])
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| 256 | l.Pos = len(l.Text)
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| 257 | return Token{Type: Error, Value: value}
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| 258 | }
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| 259 | return EOF
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| 260 | }
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| 261 |
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| 262 | // RegexLexer is the default lexer implementation used in Chroma.
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| 263 | type RegexLexer struct {
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| 264 | registry *LexerRegistry // The LexerRegistry this Lexer is associated with, if any.
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| 265 | config *Config
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| 266 | analyser func(text string) float32
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| 267 | trace bool
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| 268 |
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| 269 | mu sync.Mutex
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| 270 | compiled bool
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| 271 | rawRules Rules
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| 272 | rules map[string][]*CompiledRule
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| 273 | fetchRulesFunc func() (Rules, error)
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| 274 | compileOnce sync.Once
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| 275 | }
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| 276 |
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| 277 | func (r *RegexLexer) String() string {
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| 278 | return r.config.Name
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| 279 | }
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| 280 |
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| 281 | // Rules in the Lexer.
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| 282 | func (r *RegexLexer) Rules() (Rules, error) {
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| 283 | if err := r.needRules(); err != nil {
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| 284 | return nil, err
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| 285 | }
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| 286 | return r.rawRules, nil
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| 287 | }
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| 288 |
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| 289 | // SetRegistry the lexer will use to lookup other lexers if necessary.
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| 290 | func (r *RegexLexer) SetRegistry(registry *LexerRegistry) Lexer {
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| 291 | r.registry = registry
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| 292 | return r
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| 293 | }
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| 294 |
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| 295 | // SetAnalyser sets the analyser function used to perform content inspection.
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| 296 | func (r *RegexLexer) SetAnalyser(analyser func(text string) float32) Lexer {
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| 297 | r.analyser = analyser
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| 298 | return r
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| 299 | }
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| 300 |
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| 301 | func (r *RegexLexer) AnalyseText(text string) float32 { // nolint
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| 302 | if r.analyser != nil {
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| 303 | return r.analyser(text)
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| 304 | }
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| 305 | return 0.0
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| 306 | }
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| 307 |
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| 308 | // SetConfig replaces the Config for this Lexer.
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| 309 | func (r *RegexLexer) SetConfig(config *Config) *RegexLexer {
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| 310 | r.config = config
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| 311 | return r
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| 312 | }
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| 313 |
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| 314 | func (r *RegexLexer) Config() *Config { // nolint
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| 315 | return r.config
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| 316 | }
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| 317 |
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| 318 | // Regex compilation is deferred until the lexer is used. This is to avoid significant init() time costs.
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| 319 | func (r *RegexLexer) maybeCompile() (err error) {
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| 320 | r.mu.Lock()
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| 321 | defer r.mu.Unlock()
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| 322 | if r.compiled {
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| 323 | return nil
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| 324 | }
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| 325 | for state, rules := range r.rules {
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| 326 | for i, rule := range rules {
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| 327 | if rule.Regexp == nil {
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| 328 | pattern := "(?:" + rule.Pattern + ")"
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| 329 | if rule.flags != "" {
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| 330 | pattern = "(?" + rule.flags + ")" + pattern
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| 331 | }
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| 332 | pattern = `\G` + pattern
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| 333 | rule.Regexp, err = regexp2.Compile(pattern, regexp2.RE2)
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| 334 | if err != nil {
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| 335 | return fmt.Errorf("failed to compile rule %s.%d: %s", state, i, err)
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| 336 | }
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| 337 | rule.Regexp.MatchTimeout = time.Millisecond * 250
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| 338 | }
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| 339 | }
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| 340 | }
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| 341 | restart:
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| 342 | seen := map[LexerMutator]bool{}
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| 343 | for state := range r.rules {
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| 344 | for i := 0; i < len(r.rules[state]); i++ {
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| 345 | rule := r.rules[state][i]
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| 346 | if compile, ok := rule.Mutator.(LexerMutator); ok {
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| 347 | if seen[compile] {
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| 348 | return fmt.Errorf("saw mutator %T twice; this should not happen", compile)
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| 349 | }
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| 350 | seen[compile] = true
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| 351 | if err := compile.MutateLexer(r.rules, state, i); err != nil {
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| 352 | return err
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| 353 | }
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| 354 | // Process the rules again in case the mutator added/removed rules.
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| 355 | //
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| 356 | // This sounds bad, but shouldn't be significant in practice.
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| 357 | goto restart
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| 358 | }
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| 359 | }
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| 360 | }
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| 361 | r.compiled = true
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| 362 | return nil
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| 363 | }
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| 364 |
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| 365 | func (r *RegexLexer) fetchRules() error {
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| 366 | rules, err := r.fetchRulesFunc()
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| 367 | if err != nil {
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| 368 | return fmt.Errorf("%s: failed to compile rules: %w", r.config.Name, err)
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| 369 | }
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| 370 | if _, ok := rules["root"]; !ok {
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| 371 | return fmt.Errorf("no \"root\" state")
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| 372 | }
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| 373 | compiledRules := map[string][]*CompiledRule{}
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| 374 | for state, rules := range rules {
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| 375 | compiledRules[state] = nil
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| 376 | for _, rule := range rules {
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| 377 | flags := ""
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| 378 | if !r.config.NotMultiline {
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| 379 | flags += "m"
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| 380 | }
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| 381 | if r.config.CaseInsensitive {
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| 382 | flags += "i"
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| 383 | }
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| 384 | if r.config.DotAll {
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| 385 | flags += "s"
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| 386 | }
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| 387 | compiledRules[state] = append(compiledRules[state], &CompiledRule{Rule: rule, flags: flags})
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| 388 | }
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| 389 | }
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| 390 |
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| 391 | r.rawRules = rules
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| 392 | r.rules = compiledRules
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| 393 | return nil
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| 394 | }
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| 395 |
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| 396 | func (r *RegexLexer) needRules() error {
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| 397 | var err error
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| 398 | if r.fetchRulesFunc != nil {
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| 399 | r.compileOnce.Do(func() {
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| 400 | err = r.fetchRules()
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| 401 | })
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| 402 | }
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| 403 | if err := r.maybeCompile(); err != nil {
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| 404 | return err
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| 405 | }
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| 406 | return err
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| 407 | }
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| 408 |
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| 409 | func (r *RegexLexer) Tokenise(options *TokeniseOptions, text string) (Iterator, error) { // nolint
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| 410 | err := r.needRules()
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| 411 | if err != nil {
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| 412 | return nil, err
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| 413 | }
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| 414 | if options == nil {
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| 415 | options = defaultOptions
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| 416 | }
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| 417 | if options.EnsureLF {
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| 418 | text = ensureLF(text)
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| 419 | }
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| 420 | newlineAdded := false
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| 421 | if !options.Nested && r.config.EnsureNL && !strings.HasSuffix(text, "\n") {
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| 422 | text += "\n"
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| 423 | newlineAdded = true
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| 424 | }
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| 425 | state := &LexerState{
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| 426 | Registry: r.registry,
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| 427 | newlineAdded: newlineAdded,
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| 428 | options: options,
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| 429 | Lexer: r,
|
|---|
| 430 | Text: []rune(text),
|
|---|
| 431 | Stack: []string{options.State},
|
|---|
| 432 | Rules: r.rules,
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| 433 | MutatorContext: map[interface{}]interface{}{},
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| 434 | }
|
|---|
| 435 | return state.Iterator, nil
|
|---|
| 436 | }
|
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| 437 |
|
|---|
| 438 | // MustRules is like Rules() but will panic on error.
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| 439 | func (r *RegexLexer) MustRules() Rules {
|
|---|
| 440 | rules, err := r.Rules()
|
|---|
| 441 | if err != nil {
|
|---|
| 442 | panic(err)
|
|---|
| 443 | }
|
|---|
| 444 | return rules
|
|---|
| 445 | }
|
|---|
| 446 |
|
|---|
| 447 | func matchRules(text []rune, pos int, rules []*CompiledRule) (int, *CompiledRule, []string, map[string]string) {
|
|---|
| 448 | for i, rule := range rules {
|
|---|
| 449 | match, err := rule.Regexp.FindRunesMatchStartingAt(text, pos)
|
|---|
| 450 | if match != nil && err == nil && match.Index == pos {
|
|---|
| 451 | groups := []string{}
|
|---|
| 452 | namedGroups := make(map[string]string)
|
|---|
| 453 | for _, g := range match.Groups() {
|
|---|
| 454 | namedGroups[g.Name] = g.String()
|
|---|
| 455 | groups = append(groups, g.String())
|
|---|
| 456 | }
|
|---|
| 457 | return i, rule, groups, namedGroups
|
|---|
| 458 | }
|
|---|
| 459 | }
|
|---|
| 460 | return 0, &CompiledRule{}, nil, nil
|
|---|
| 461 | }
|
|---|
| 462 |
|
|---|
| 463 | // replace \r and \r\n with \n
|
|---|
| 464 | // same as strings.ReplaceAll but more efficient
|
|---|
| 465 | func ensureLF(text string) string {
|
|---|
| 466 | buf := make([]byte, len(text))
|
|---|
| 467 | var j int
|
|---|
| 468 | for i := 0; i < len(text); i++ {
|
|---|
| 469 | c := text[i]
|
|---|
| 470 | if c == '\r' {
|
|---|
| 471 | if i < len(text)-1 && text[i+1] == '\n' {
|
|---|
| 472 | continue
|
|---|
| 473 | }
|
|---|
| 474 | c = '\n'
|
|---|
| 475 | }
|
|---|
| 476 | buf[j] = c
|
|---|
| 477 | j++
|
|---|
| 478 | }
|
|---|
| 479 | return string(buf[:j])
|
|---|
| 480 | }
|
|---|
