cheat/vendor/github.com/alecthomas/chroma/v2/serialise.go

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package chroma
import (
"compress/gzip"
"encoding/xml"
"errors"
"fmt"
"io"
"io/fs"
"math"
"path/filepath"
"reflect"
"regexp"
"strings"
"github.com/dlclark/regexp2"
)
// Serialisation of Chroma rules to XML. The format is:
//
// <rules>
// <state name="$STATE">
// <rule [pattern="$PATTERN"]>
// [<$EMITTER ...>]
// [<$MUTATOR ...>]
// </rule>
// </state>
// </rules>
//
// eg. Include("String") would become:
//
// <rule>
// <include state="String" />
// </rule>
//
// [null, null, {"kind": "include", "state": "String"}]
//
// eg. Rule{`\d+`, Text, nil} would become:
//
// <rule pattern="\\d+">
// <token type="Text"/>
// </rule>
//
// eg. Rule{`"`, String, Push("String")}
//
// <rule pattern="\"">
// <token type="String" />
// <push state="String" />
// </rule>
//
// eg. Rule{`(\w+)(\n)`, ByGroups(Keyword, Whitespace), nil},
//
// <rule pattern="(\\w+)(\\n)">
// <bygroups token="Keyword" token="Whitespace" />
// <push state="String" />
// </rule>
var (
// ErrNotSerialisable is returned if a lexer contains Rules that cannot be serialised.
ErrNotSerialisable = fmt.Errorf("not serialisable")
emitterTemplates = func() map[string]SerialisableEmitter {
out := map[string]SerialisableEmitter{}
for _, emitter := range []SerialisableEmitter{
&byGroupsEmitter{},
&usingSelfEmitter{},
TokenType(0),
&usingEmitter{},
&usingByGroup{},
} {
out[emitter.EmitterKind()] = emitter
}
return out
}()
mutatorTemplates = func() map[string]SerialisableMutator {
out := map[string]SerialisableMutator{}
for _, mutator := range []SerialisableMutator{
&includeMutator{},
&combinedMutator{},
&multiMutator{},
&pushMutator{},
&popMutator{},
} {
out[mutator.MutatorKind()] = mutator
}
return out
}()
)
// fastUnmarshalConfig unmarshals only the Config from a serialised lexer.
func fastUnmarshalConfig(from fs.FS, path string) (*Config, error) {
r, err := from.Open(path)
if err != nil {
return nil, err
}
defer r.Close()
dec := xml.NewDecoder(r)
for {
token, err := dec.Token()
if err != nil {
if errors.Is(err, io.EOF) {
return nil, fmt.Errorf("could not find <config> element")
}
return nil, err
}
switch se := token.(type) {
case xml.StartElement:
if se.Name.Local != "config" {
break
}
var config Config
err = dec.DecodeElement(&config, &se)
if err != nil {
return nil, fmt.Errorf("%s: %w", path, err)
}
return &config, nil
}
}
}
// MustNewXMLLexer constructs a new RegexLexer from an XML file or panics.
func MustNewXMLLexer(from fs.FS, path string) *RegexLexer {
lex, err := NewXMLLexer(from, path)
if err != nil {
panic(err)
}
return lex
}
// NewXMLLexer creates a new RegexLexer from a serialised RegexLexer.
func NewXMLLexer(from fs.FS, path string) (*RegexLexer, error) {
config, err := fastUnmarshalConfig(from, path)
if err != nil {
return nil, err
}
for _, glob := range append(config.Filenames, config.AliasFilenames...) {
_, err := filepath.Match(glob, "")
if err != nil {
return nil, fmt.Errorf("%s: %q is not a valid glob: %w", config.Name, glob, err)
}
}
var analyserFn func(string) float32
if config.Analyse != nil {
type regexAnalyse struct {
re *regexp2.Regexp
score float32
}
regexAnalysers := make([]regexAnalyse, 0, len(config.Analyse.Regexes))
for _, ra := range config.Analyse.Regexes {
re, err := regexp2.Compile(ra.Pattern, regexp2.None)
if err != nil {
return nil, fmt.Errorf("%s: %q is not a valid analyser regex: %w", config.Name, ra.Pattern, err)
}
regexAnalysers = append(regexAnalysers, regexAnalyse{re, ra.Score})
}
analyserFn = func(text string) float32 {
var score float32
for _, ra := range regexAnalysers {
ok, err := ra.re.MatchString(text)
if err != nil {
return 0
}
if ok && config.Analyse.First {
return float32(math.Min(float64(ra.score), 1.0))
}
if ok {
score += ra.score
}
}
return float32(math.Min(float64(score), 1.0))
}
}
return &RegexLexer{
config: config,
analyser: analyserFn,
fetchRulesFunc: func() (Rules, error) {
var lexer struct {
Config
Rules Rules `xml:"rules"`
}
// Try to open .xml fallback to .xml.gz
fr, err := from.Open(path)
if err != nil {
if errors.Is(err, fs.ErrNotExist) {
path += ".gz"
fr, err = from.Open(path)
if err != nil {
return nil, err
}
} else {
return nil, err
}
}
defer fr.Close()
var r io.Reader = fr
if strings.HasSuffix(path, ".gz") {
r, err = gzip.NewReader(r)
if err != nil {
return nil, fmt.Errorf("%s: %w", path, err)
}
}
err = xml.NewDecoder(r).Decode(&lexer)
if err != nil {
return nil, fmt.Errorf("%s: %w", path, err)
}
return lexer.Rules, nil
},
}, nil
}
// Marshal a RegexLexer to XML.
func Marshal(l *RegexLexer) ([]byte, error) {
type lexer struct {
Config Config `xml:"config"`
Rules Rules `xml:"rules"`
}
rules, err := l.Rules()
if err != nil {
return nil, err
}
root := &lexer{
Config: *l.Config(),
Rules: rules,
}
data, err := xml.MarshalIndent(root, "", " ")
if err != nil {
return nil, err
}
re := regexp.MustCompile(`></[a-zA-Z]+>`)
data = re.ReplaceAll(data, []byte(`/>`))
return data, nil
}
// Unmarshal a RegexLexer from XML.
func Unmarshal(data []byte) (*RegexLexer, error) {
type lexer struct {
Config Config `xml:"config"`
Rules Rules `xml:"rules"`
}
root := &lexer{}
err := xml.Unmarshal(data, root)
if err != nil {
return nil, fmt.Errorf("invalid Lexer XML: %w", err)
}
lex, err := NewLexer(&root.Config, func() Rules { return root.Rules })
if err != nil {
return nil, err
}
return lex, nil
}
func marshalMutator(e *xml.Encoder, mutator Mutator) error {
if mutator == nil {
return nil
}
smutator, ok := mutator.(SerialisableMutator)
if !ok {
return fmt.Errorf("unsupported mutator: %w", ErrNotSerialisable)
}
return e.EncodeElement(mutator, xml.StartElement{Name: xml.Name{Local: smutator.MutatorKind()}})
}
func unmarshalMutator(d *xml.Decoder, start xml.StartElement) (Mutator, error) {
kind := start.Name.Local
mutator, ok := mutatorTemplates[kind]
if !ok {
return nil, fmt.Errorf("unknown mutator %q: %w", kind, ErrNotSerialisable)
}
value, target := newFromTemplate(mutator)
if err := d.DecodeElement(target, &start); err != nil {
return nil, err
}
return value().(SerialisableMutator), nil
}
func marshalEmitter(e *xml.Encoder, emitter Emitter) error {
if emitter == nil {
return nil
}
semitter, ok := emitter.(SerialisableEmitter)
if !ok {
return fmt.Errorf("unsupported emitter %T: %w", emitter, ErrNotSerialisable)
}
return e.EncodeElement(emitter, xml.StartElement{
Name: xml.Name{Local: semitter.EmitterKind()},
})
}
func unmarshalEmitter(d *xml.Decoder, start xml.StartElement) (Emitter, error) {
kind := start.Name.Local
mutator, ok := emitterTemplates[kind]
if !ok {
return nil, fmt.Errorf("unknown emitter %q: %w", kind, ErrNotSerialisable)
}
value, target := newFromTemplate(mutator)
if err := d.DecodeElement(target, &start); err != nil {
return nil, err
}
return value().(SerialisableEmitter), nil
}
func (r Rule) MarshalXML(e *xml.Encoder, _ xml.StartElement) error {
start := xml.StartElement{
Name: xml.Name{Local: "rule"},
}
if r.Pattern != "" {
start.Attr = append(start.Attr, xml.Attr{
Name: xml.Name{Local: "pattern"},
Value: r.Pattern,
})
}
if err := e.EncodeToken(start); err != nil {
return err
}
if err := marshalEmitter(e, r.Type); err != nil {
return err
}
if err := marshalMutator(e, r.Mutator); err != nil {
return err
}
return e.EncodeToken(xml.EndElement{Name: start.Name})
}
func (r *Rule) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
for _, attr := range start.Attr {
if attr.Name.Local == "pattern" {
r.Pattern = attr.Value
break
}
}
for {
token, err := d.Token()
if err != nil {
return err
}
switch token := token.(type) {
case xml.StartElement:
mutator, err := unmarshalMutator(d, token)
if err != nil && !errors.Is(err, ErrNotSerialisable) {
return err
} else if err == nil {
if r.Mutator != nil {
return fmt.Errorf("duplicate mutator")
}
r.Mutator = mutator
continue
}
emitter, err := unmarshalEmitter(d, token)
if err != nil && !errors.Is(err, ErrNotSerialisable) { // nolint: gocritic
return err
} else if err == nil {
if r.Type != nil {
return fmt.Errorf("duplicate emitter")
}
r.Type = emitter
continue
} else {
return err
}
case xml.EndElement:
return nil
}
}
}
type xmlRuleState struct {
Name string `xml:"name,attr"`
Rules []Rule `xml:"rule"`
}
type xmlRules struct {
States []xmlRuleState `xml:"state"`
}
func (r Rules) MarshalXML(e *xml.Encoder, _ xml.StartElement) error {
xr := xmlRules{}
for state, rules := range r {
xr.States = append(xr.States, xmlRuleState{
Name: state,
Rules: rules,
})
}
return e.EncodeElement(xr, xml.StartElement{Name: xml.Name{Local: "rules"}})
}
func (r *Rules) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
xr := xmlRules{}
if err := d.DecodeElement(&xr, &start); err != nil {
return err
}
if *r == nil {
*r = Rules{}
}
for _, state := range xr.States {
(*r)[state.Name] = state.Rules
}
return nil
}
type xmlTokenType struct {
Type string `xml:"type,attr"`
}
func (t *TokenType) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
el := xmlTokenType{}
if err := d.DecodeElement(&el, &start); err != nil {
return err
}
tt, err := TokenTypeString(el.Type)
if err != nil {
return err
}
*t = tt
return nil
}
func (t TokenType) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
start.Attr = append(start.Attr, xml.Attr{Name: xml.Name{Local: "type"}, Value: t.String()})
if err := e.EncodeToken(start); err != nil {
return err
}
return e.EncodeToken(xml.EndElement{Name: start.Name})
}
// This hijinks is a bit unfortunate but without it we can't deserialise into TokenType.
func newFromTemplate(template interface{}) (value func() interface{}, target interface{}) {
t := reflect.TypeOf(template)
if t.Kind() == reflect.Ptr {
v := reflect.New(t.Elem())
return v.Interface, v.Interface()
}
v := reflect.New(t)
return func() interface{} { return v.Elem().Interface() }, v.Interface()
}
func (b *Emitters) UnmarshalXML(d *xml.Decoder, start xml.StartElement) error {
for {
token, err := d.Token()
if err != nil {
return err
}
switch token := token.(type) {
case xml.StartElement:
emitter, err := unmarshalEmitter(d, token)
if err != nil {
return err
}
*b = append(*b, emitter)
case xml.EndElement:
return nil
}
}
}
func (b Emitters) MarshalXML(e *xml.Encoder, start xml.StartElement) error {
if err := e.EncodeToken(start); err != nil {
return err
}
for _, m := range b {
if err := marshalEmitter(e, m); err != nil {
return err
}
}
return e.EncodeToken(xml.EndElement{Name: start.Name})
}