1package chroma
2
3import (
4 "compress/gzip"
5 "encoding/xml"
6 "errors"
7 "fmt"
8 "io"
9 "io/fs"
10 "math"
11 "path/filepath"
12 "reflect"
13 "regexp"
14 "strings"
15
16 "github.com/dlclark/regexp2"
17)
18
19// Serialisation of Chroma rules to XML. The format is:
20//
21// <rules>
22// <state name="$STATE">
23// <rule [pattern="$PATTERN"]>
24// [<$EMITTER ...>]
25// [<$MUTATOR ...>]
26// </rule>
27// </state>
28// </rules>
29//
30// eg. Include("String") would become:
31//
32// <rule>
33// <include state="String" />
34// </rule>
35//
36// [null, null, {"kind": "include", "state": "String"}]
37//
38// eg. Rule{`\d+`, Text, nil} would become:
39//
40// <rule pattern="\\d+">
41// <token type="Text"/>
42// </rule>
43//
44// eg. Rule{`"`, String, Push("String")}
45//
46// <rule pattern="\"">
47// <token type="String" />
48// <push state="String" />
49// </rule>
50//
51// eg. Rule{`(\w+)(\n)`, ByGroups(Keyword, Whitespace), nil},
52//
53// <rule pattern="(\\w+)(\\n)">
54// <bygroups token="Keyword" token="Whitespace" />
55// <push state="String" />
56// </rule>
57var (
58 // ErrNotSerialisable is returned if a lexer contains Rules that cannot be serialised.
59 ErrNotSerialisable = fmt.Errorf("not serialisable")
60 emitterTemplates = func() map[string]SerialisableEmitter {
61 out := map[string]SerialisableEmitter{}
62 for _, emitter := range []SerialisableEmitter{
63 &byGroupsEmitter{},
64 &usingSelfEmitter{},
65 TokenType(0),
66 &usingEmitter{},
67 &usingByGroup{},
68 } {
69 out[emitter.EmitterKind()] = emitter
70 }
71 return out
72 }()
73 mutatorTemplates = func() map[string]SerialisableMutator {
74 out := map[string]SerialisableMutator{}
75 for _, mutator := range []SerialisableMutator{
76 &includeMutator{},
77 &combinedMutator{},
78 &multiMutator{},
79 &pushMutator{},
80 &popMutator{},
81 } {
82 out[mutator.MutatorKind()] = mutator
83 }
84 return out
85 }()
86)
87
88// fastUnmarshalConfig unmarshals only the Config from a serialised lexer.
89func fastUnmarshalConfig(from fs.FS, path string) (*Config, error) {
90 r, err := from.Open(path)
91 if err != nil {
92 return nil, err
93 }
94 defer r.Close()
95 dec := xml.NewDecoder(r)
96 for {
97 token, err := dec.Token()
98 if err != nil {
99 if errors.Is(err, io.EOF) {
100 return nil, fmt.Errorf("could not find <config> element")
101 }
102 return nil, err
103 }
104 switch se := token.(type) {
105 case xml.StartElement:
106 if se.Name.Local != "config" {
107 break
108 }
109
110 var config Config
111 err = dec.DecodeElement(&config, &se)
112 if err != nil {
113 return nil, fmt.Errorf("%s: %w", path, err)
114 }
115 return &config, nil
116 }
117 }
118}
119
120// MustNewXMLLexer constructs a new RegexLexer from an XML file or panics.
121func MustNewXMLLexer(from fs.FS, path string) *RegexLexer {
122 lex, err := NewXMLLexer(from, path)
123 if err != nil {
124 panic(err)
125 }
126 return lex
127}
128
129// NewXMLLexer creates a new RegexLexer from a serialised RegexLexer.
130func NewXMLLexer(from fs.FS, path string) (*RegexLexer, error) {
131 config, err := fastUnmarshalConfig(from, path)
132 if err != nil {
133 return nil, err
134 }
135
136 for _, glob := range append(config.Filenames, config.AliasFilenames...) {
137 _, err := filepath.Match(glob, "")
138 if err != nil {
139 return nil, fmt.Errorf("%s: %q is not a valid glob: %w", config.Name, glob, err)
140 }
141 }
142
143 var analyserFn func(string) float32
144
145 if config.Analyse != nil {
146 type regexAnalyse struct {
147 re *regexp2.Regexp
148 score float32
149 }
150
151 regexAnalysers := make([]regexAnalyse, 0, len(config.Analyse.Regexes))
152
153 for _, ra := range config.Analyse.Regexes {
154 re, err := regexp2.Compile(ra.Pattern, regexp2.None)
155 if err != nil {
156 return nil, fmt.Errorf("%s: %q is not a valid analyser regex: %w", config.Name, ra.Pattern, err)
157 }
158
159 regexAnalysers = append(regexAnalysers, regexAnalyse{re, ra.Score})
160 }
161
162 analyserFn = func(text string) float32 {
163 var score float32
164
165 for _, ra := range regexAnalysers {
166 ok, err := ra.re.MatchString(text)
167 if err != nil {
168 return 0
169 }
170
171 if ok && config.Analyse.First {
172 return float32(math.Min(float64(ra.score), 1.0))
173 }
174
175 if ok {
176 score += ra.score
177 }
178 }
179
180 return float32(math.Min(float64(score), 1.0))
181 }
182 }
183
184 return &RegexLexer{
185 config: config,
186 analyser: analyserFn,
187 fetchRulesFunc: func() (Rules, error) {
188 var lexer struct {
189 Config
190 Rules Rules `xml:"rules"`
191 }
192 // Try to open .xml fallback to .xml.gz
193 fr, err := from.Open(path)
194 if err != nil {
195 if errors.Is(err, fs.ErrNotExist) {
196 path += ".gz"
197 fr, err = from.Open(path)
198 if err != nil {
199 return nil, err
200 }
201 } else {
202 return nil, err
203 }
204 }
205 defer fr.Close()
206 var r io.Reader = fr
207 if strings.HasSuffix(path, ".gz") {
208 r, err = gzip.NewReader(r)
209 if err != nil {
210 return nil, fmt.Errorf("%s: %w", path, err)
211 }
212 }
213 err = xml.NewDecoder(r).Decode(&lexer)
214 if err != nil {
215 return nil, fmt.Errorf("%s: %w", path, err)
216 }
217 return lexer.Rules, nil
218 },
219 }, nil
220}
221
222// Marshal a RegexLexer to XML.
223func Marshal(l *RegexLexer) ([]byte, error) {
224 type lexer struct {
225 Config Config `xml:"config"`
226 Rules Rules `xml:"rules"`
227 }
228
229 rules, err := l.Rules()
230 if err != nil {
231 return nil, err
232 }
233 root := &lexer{
234 Config: *l.Config(),
235 Rules: rules,
236 }
237 data, err := xml.MarshalIndent(root, "", " ")
238 if err != nil {
239 return nil, err
240 }
241 re := regexp.MustCompile(`></[a-zA-Z]+>`)
242 data = re.ReplaceAll(data, []byte(`/>`))
243 return data, nil
244}
245
246// Unmarshal a RegexLexer from XML.
247func Unmarshal(data []byte) (*RegexLexer, error) {
248 type lexer struct {
249 Config Config `xml:"config"`
250 Rules Rules `xml:"rules"`
251 }
252 root := &lexer{}
253 err := xml.Unmarshal(data, root)
254 if err != nil {
255 return nil, fmt.Errorf("invalid Lexer XML: %w", err)
256 }
257 lex, err := NewLexer(&root.Config, func() Rules { return root.Rules })
258 if err != nil {
259 return nil, err
260 }
261 return lex, nil
262}
263
264func marshalMutator(e *xml.Encoder, mutator Mutator) error {
265 if mutator == nil {
266 return nil
267 }
268 smutator, ok := mutator.(SerialisableMutator)
269 if !ok {
270 return fmt.Errorf("unsupported mutator: %w", ErrNotSerialisable)
271 }
272 return e.EncodeElement(mutator, xml.StartElement{Name: xml.Name{Local: smutator.MutatorKind()}})
273}
274
275func unmarshalMutator(d *xml.Decoder, start xml.StartElement) (Mutator, error) {
276 kind := start.Name.Local
277 mutator, ok := mutatorTemplates[kind]
278 if !ok {
279 return nil, fmt.Errorf("unknown mutator %q: %w", kind, ErrNotSerialisable)
280 }
281 value, target := newFromTemplate(mutator)
282 if err := d.DecodeElement(target, &start); err != nil {
283 return nil, err
284 }
285 return value().(SerialisableMutator), nil
286}
287
288func marshalEmitter(e *xml.Encoder, emitter Emitter) error {
289 if emitter == nil {
290 return nil
291 }
292 semitter, ok := emitter.(SerialisableEmitter)
293 if !ok {
294 return fmt.Errorf("unsupported emitter %T: %w", emitter, ErrNotSerialisable)
295 }
296 return e.EncodeElement(emitter, xml.StartElement{
297 Name: xml.Name{Local: semitter.EmitterKind()},
298 })
299}
300
301func unmarshalEmitter(d *xml.Decoder, start xml.StartElement) (Emitter, error) {
302 kind := start.Name.Local
303 mutator, ok := emitterTemplates[kind]
304 if !ok {
305 return nil, fmt.Errorf("unknown emitter %q: %w", kind, ErrNotSerialisable)
306 }
307 value, target := newFromTemplate(mutator)
308 if err := d.DecodeElement(target, &start); err != nil {
309 return nil, err
310 }
311 return value().(SerialisableEmitter), nil
312}
313
314func (r Rule) MarshalXML(e *xml.Encoder, _ xml.StartElement) error {
315 start := xml.StartElement{
316 Name: xml.Name{Local: "rule"},
317 }
318 if r.Pattern != "" {
319 start.Attr = append(start.Attr, xml.Attr{
320 Name: xml.Name{Local: "pattern"},
321 Value: r.Pattern,
322 })
323 }
324 if err := e.EncodeToken(start); err != nil {
325 return err
326 }
327 if err := marshalEmitter(e, r.Type); err != nil {
328 return err
329 }
330 if err := marshalMutator(e, r.Mutator); err != nil {
331 return err
332 }
333 return e.EncodeToken(xml.EndElement{Name: start.Name})
334}
335
336func (r *Rule) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
337 for _, attr := range start.Attr {
338 if attr.Name.Local == "pattern" {
339 r.Pattern = attr.Value
340 break
341 }
342 }
343 for {
344 token, err := d.Token()
345 if err != nil {
346 return err
347 }
348 switch token := token.(type) {
349 case xml.StartElement:
350 mutator, err := unmarshalMutator(d, token)
351 if err != nil && !errors.Is(err, ErrNotSerialisable) {
352 return err
353 } else if err == nil {
354 if r.Mutator != nil {
355 return fmt.Errorf("duplicate mutator")
356 }
357 r.Mutator = mutator
358 continue
359 }
360 emitter, err := unmarshalEmitter(d, token)
361 if err != nil && !errors.Is(err, ErrNotSerialisable) { // nolint: gocritic
362 return err
363 } else if err == nil {
364 if r.Type != nil {
365 return fmt.Errorf("duplicate emitter")
366 }
367 r.Type = emitter
368 continue
369 } else {
370 return err
371 }
372
373 case xml.EndElement:
374 return nil
375 }
376 }
377}
378
379type xmlRuleState struct {
380 Name string `xml:"name,attr"`
381 Rules []Rule `xml:"rule"`
382}
383
384type xmlRules struct {
385 States []xmlRuleState `xml:"state"`
386}
387
388func (r Rules) MarshalXML(e *xml.Encoder, _ xml.StartElement) error {
389 xr := xmlRules{}
390 for state, rules := range r {
391 xr.States = append(xr.States, xmlRuleState{
392 Name: state,
393 Rules: rules,
394 })
395 }
396 return e.EncodeElement(xr, xml.StartElement{Name: xml.Name{Local: "rules"}})
397}
398
399func (r *Rules) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
400 xr := xmlRules{}
401 if err := d.DecodeElement(&xr, &start); err != nil {
402 return err
403 }
404 if *r == nil {
405 *r = Rules{}
406 }
407 for _, state := range xr.States {
408 (*r)[state.Name] = state.Rules
409 }
410 return nil
411}
412
413type xmlTokenType struct {
414 Type string `xml:"type,attr"`
415}
416
417func (t *TokenType) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
418 el := xmlTokenType{}
419 if err := d.DecodeElement(&el, &start); err != nil {
420 return err
421 }
422 tt, err := TokenTypeString(el.Type)
423 if err != nil {
424 return err
425 }
426 *t = tt
427 return nil
428}
429
430func (t TokenType) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
431 start.Attr = append(start.Attr, xml.Attr{Name: xml.Name{Local: "type"}, Value: t.String()})
432 if err := e.EncodeToken(start); err != nil {
433 return err
434 }
435 return e.EncodeToken(xml.EndElement{Name: start.Name})
436}
437
438// This hijinks is a bit unfortunate but without it we can't deserialise into TokenType.
439func newFromTemplate(template interface{}) (value func() interface{}, target interface{}) {
440 t := reflect.TypeOf(template)
441 if t.Kind() == reflect.Ptr {
442 v := reflect.New(t.Elem())
443 return v.Interface, v.Interface()
444 }
445 v := reflect.New(t)
446 return func() interface{} { return v.Elem().Interface() }, v.Interface()
447}
448
449func (b *Emitters) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
450 for {
451 token, err := d.Token()
452 if err != nil {
453 return err
454 }
455 switch token := token.(type) {
456 case xml.StartElement:
457 emitter, err := unmarshalEmitter(d, token)
458 if err != nil {
459 return err
460 }
461 *b = append(*b, emitter)
462
463 case xml.EndElement:
464 return nil
465 }
466 }
467}
468
469func (b Emitters) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
470 if err := e.EncodeToken(start); err != nil {
471 return err
472 }
473 for _, m := range b {
474 if err := marshalEmitter(e, m); err != nil {
475 return err
476 }
477 }
478 return e.EncodeToken(xml.EndElement{Name: start.Name})
479}