/
css_parser.go
1344 lines (1178 loc) · 37.2 KB
/
css_parser.go
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package css_parser
import (
"fmt"
"strings"
"github.com/evanw/esbuild/internal/ast"
"github.com/evanw/esbuild/internal/compat"
"github.com/evanw/esbuild/internal/css_ast"
"github.com/evanw/esbuild/internal/css_lexer"
"github.com/evanw/esbuild/internal/logger"
)
// This is mostly a normal CSS parser with one exception: the addition of
// support for parsing https://drafts.csswg.org/css-nesting-1/.
type parser struct {
log logger.Log
source logger.Source
tracker logger.LineColumnTracker
options Options
tokens []css_lexer.Token
legalComments []css_lexer.Comment
stack []css_lexer.T
index int
end int
legalCommentIndex int
prevError logger.Loc
importRecords []ast.ImportRecord
}
type Options struct {
UnsupportedCSSFeatures compat.CSSFeature
MangleSyntax bool
RemoveWhitespace bool
}
func Parse(log logger.Log, source logger.Source, options Options) css_ast.AST {
result := css_lexer.Tokenize(log, source)
p := parser{
log: log,
source: source,
tracker: logger.MakeLineColumnTracker(&source),
options: options,
tokens: result.Tokens,
legalComments: result.LegalComments,
prevError: logger.Loc{Start: -1},
}
p.end = len(p.tokens)
rules := p.parseListOfRules(ruleContext{
isTopLevel: true,
parseSelectors: true,
})
p.expect(css_lexer.TEndOfFile)
return css_ast.AST{
Rules: rules,
ImportRecords: p.importRecords,
ApproximateLineCount: result.ApproximateLineCount,
SourceMapComment: result.SourceMapComment,
}
}
func (p *parser) advance() {
if p.index < p.end {
p.index++
}
}
func (p *parser) at(index int) css_lexer.Token {
if index < p.end {
return p.tokens[index]
}
if p.end < len(p.tokens) {
return css_lexer.Token{
Kind: css_lexer.TEndOfFile,
Range: logger.Range{Loc: p.tokens[p.end].Range.Loc},
}
}
return css_lexer.Token{
Kind: css_lexer.TEndOfFile,
Range: logger.Range{Loc: logger.Loc{Start: int32(len(p.source.Contents))}},
}
}
func (p *parser) current() css_lexer.Token {
return p.at(p.index)
}
func (p *parser) next() css_lexer.Token {
return p.at(p.index + 1)
}
func (p *parser) raw() string {
t := p.current()
return p.source.Contents[t.Range.Loc.Start:t.Range.End()]
}
func (p *parser) decoded() string {
return p.current().DecodedText(p.source.Contents)
}
func (p *parser) peek(kind css_lexer.T) bool {
return kind == p.current().Kind
}
func (p *parser) eat(kind css_lexer.T) bool {
if p.peek(kind) {
p.advance()
return true
}
return false
}
func (p *parser) expect(kind css_lexer.T) bool {
if p.eat(kind) {
return true
}
t := p.current()
var text string
if kind == css_lexer.TSemicolon && p.index > 0 && p.at(p.index-1).Kind == css_lexer.TWhitespace {
// Have a nice error message for forgetting a trailing semicolon
text = "Expected \";\""
t = p.at(p.index - 1)
} else {
switch t.Kind {
case css_lexer.TEndOfFile, css_lexer.TWhitespace:
text = fmt.Sprintf("Expected %s but found %s", kind.String(), t.Kind.String())
t.Range.Len = 0
case css_lexer.TBadURL, css_lexer.TBadString:
text = fmt.Sprintf("Expected %s but found %s", kind.String(), t.Kind.String())
default:
text = fmt.Sprintf("Expected %s but found %q", kind.String(), p.raw())
}
}
if t.Range.Loc.Start > p.prevError.Start {
p.log.AddRangeWarning(&p.tracker, t.Range, text)
p.prevError = t.Range.Loc
}
return false
}
func (p *parser) unexpected() {
if t := p.current(); t.Range.Loc.Start > p.prevError.Start {
var text string
switch t.Kind {
case css_lexer.TEndOfFile, css_lexer.TWhitespace:
text = fmt.Sprintf("Unexpected %s", t.Kind.String())
t.Range.Len = 0
case css_lexer.TBadURL, css_lexer.TBadString:
text = fmt.Sprintf("Unexpected %s", t.Kind.String())
default:
text = fmt.Sprintf("Unexpected %q", p.raw())
}
p.log.AddRangeWarning(&p.tracker, t.Range, text)
p.prevError = t.Range.Loc
}
}
type ruleContext struct {
isTopLevel bool
parseSelectors bool
}
func (p *parser) parseListOfRules(context ruleContext) []css_ast.Rule {
didWarnAboutCharset := false
didWarnAboutImport := false
rules := []css_ast.Rule{}
locs := []logger.Loc{}
loop:
for {
// If there are any legal comments immediately before the current token,
// turn them all into comment rules and append them to the current rule list
for p.legalCommentIndex < len(p.legalComments) {
comment := p.legalComments[p.legalCommentIndex]
if comment.TokenIndexAfter > uint32(p.index) {
break
}
if comment.TokenIndexAfter == uint32(p.index) {
rules = append(rules, css_ast.Rule{Loc: comment.Loc, Data: &css_ast.RComment{Text: comment.Text}})
if context.isTopLevel {
locs = append(locs, comment.Loc)
}
}
p.legalCommentIndex++
}
switch p.current().Kind {
case css_lexer.TEndOfFile, css_lexer.TCloseBrace:
break loop
case css_lexer.TWhitespace:
p.advance()
continue
case css_lexer.TAtKeyword:
first := p.current().Range
rule := p.parseAtRule(atRuleContext{})
// Validate structure
if context.isTopLevel {
switch rule.Data.(type) {
case *css_ast.RAtCharset:
if !didWarnAboutCharset {
for i, before := range rules {
if _, ok := before.Data.(*css_ast.RComment); !ok {
p.log.AddRangeWarningWithNotes(&p.tracker, first, "\"@charset\" must be the first rule in the file",
[]logger.MsgData{logger.RangeData(&p.tracker, logger.Range{Loc: locs[i]},
"This rule cannot come before a \"@charset\" rule")})
didWarnAboutCharset = true
}
}
}
case *css_ast.RAtImport:
if !didWarnAboutImport {
importLoop:
for i, before := range rules {
switch before.Data.(type) {
case *css_ast.RComment, *css_ast.RAtCharset, *css_ast.RAtImport:
default:
p.log.AddRangeWarningWithNotes(&p.tracker, first, "All \"@import\" rules must come first",
[]logger.MsgData{logger.RangeData(&p.tracker, logger.Range{Loc: locs[i]},
"This rule cannot come before an \"@import\" rule")})
didWarnAboutImport = true
break importLoop
}
}
}
}
}
rules = append(rules, rule)
if context.isTopLevel {
locs = append(locs, first.Loc)
}
continue
case css_lexer.TCDO, css_lexer.TCDC:
if context.isTopLevel {
p.advance()
continue
}
}
if context.isTopLevel {
locs = append(locs, p.current().Range.Loc)
}
if context.parseSelectors {
rules = append(rules, p.parseSelectorRule())
} else {
rules = append(rules, p.parseQualifiedRuleFrom(p.index, false /* isAlreadyInvalid */))
}
}
if p.options.MangleSyntax {
rules = mangleRules(rules)
}
return rules
}
func (p *parser) parseListOfDeclarations() (list []css_ast.Rule) {
for {
switch p.current().Kind {
case css_lexer.TWhitespace, css_lexer.TSemicolon:
p.advance()
case css_lexer.TEndOfFile, css_lexer.TCloseBrace:
list = p.processDeclarations(list)
if p.options.MangleSyntax {
list = mangleRules(list)
}
return
case css_lexer.TAtKeyword:
list = append(list, p.parseAtRule(atRuleContext{
isDeclarationList: true,
}))
case css_lexer.TDelimAmpersand:
// Reference: https://drafts.csswg.org/css-nesting-1/
list = append(list, p.parseSelectorRule())
default:
list = append(list, p.parseDeclaration())
}
}
}
func mangleRules(rules []css_ast.Rule) []css_ast.Rule {
type hashEntry struct {
indices []uint32
}
// Remove empty rules
n := 0
for _, rule := range rules {
switch r := rule.Data.(type) {
case *css_ast.RAtKeyframes:
// Do not remove empty "@keyframe foo {}" rules. Even empty rules still
// dispatch JavaScript animation events, so removing them changes
// behavior: https://bugzilla.mozilla.org/show_bug.cgi?id=1004377.
case *css_ast.RKnownAt:
if len(r.Rules) == 0 {
continue
}
case *css_ast.RSelector:
if len(r.Rules) == 0 {
continue
}
}
rules[n] = rule
n++
}
rules = rules[:n]
// Remove duplicate rules, scanning from the back so we keep the last duplicate
start := n
entries := make(map[uint32]hashEntry)
skipRule:
for i := n - 1; i >= 0; i-- {
rule := rules[i]
// Merge adjacent selectors with the same content
// "a { color: red; } b { color: red; }" => "a, b { color: red; }"
if i > 0 {
if r, ok := rule.Data.(*css_ast.RSelector); ok {
if prev, ok := rules[i-1].Data.(*css_ast.RSelector); ok && css_ast.RulesEqual(r.Rules, prev.Rules) &&
isSafeSelectors(r.Selectors) && isSafeSelectors(prev.Selectors) {
nextSelector:
for _, sel := range r.Selectors {
for _, prevSel := range prev.Selectors {
if sel.Equal(prevSel) {
// Don't add duplicate selectors more than once
continue nextSelector
}
}
prev.Selectors = append(prev.Selectors, sel)
}
continue skipRule
}
}
}
// For duplicate rules, omit all but the last copy
if hash, ok := rule.Data.Hash(); ok {
entry := entries[hash]
for _, index := range entry.indices {
if rule.Data.Equal(rules[index].Data) {
continue skipRule
}
}
entry.indices = append(entry.indices, uint32(i))
entries[hash] = entry
}
start--
rules[start] = rule
}
return rules[start:]
}
// Reference: https://developer.mozilla.org/en-US/docs/Web/HTML/Element
var nonDeprecatedElementsSupportedByIE7 = map[string]bool{
"a": true,
"abbr": true,
"address": true,
"area": true,
"b": true,
"base": true,
"blockquote": true,
"body": true,
"br": true,
"button": true,
"caption": true,
"cite": true,
"code": true,
"col": true,
"colgroup": true,
"dd": true,
"del": true,
"dfn": true,
"div": true,
"dl": true,
"dt": true,
"em": true,
"embed": true,
"fieldset": true,
"form": true,
"h1": true,
"h2": true,
"h3": true,
"h4": true,
"h5": true,
"h6": true,
"head": true,
"hr": true,
"html": true,
"i": true,
"iframe": true,
"img": true,
"input": true,
"ins": true,
"kbd": true,
"label": true,
"legend": true,
"li": true,
"link": true,
"map": true,
"menu": true,
"meta": true,
"noscript": true,
"object": true,
"ol": true,
"optgroup": true,
"option": true,
"p": true,
"param": true,
"pre": true,
"q": true,
"ruby": true,
"s": true,
"samp": true,
"script": true,
"select": true,
"small": true,
"span": true,
"strong": true,
"style": true,
"sub": true,
"sup": true,
"table": true,
"tbody": true,
"td": true,
"textarea": true,
"tfoot": true,
"th": true,
"thead": true,
"title": true,
"tr": true,
"u": true,
"ul": true,
"var": true,
}
// This only returns true if all of these selectors are considered "safe" which
// means that they are very likely to work in any browser a user might reasonably
// be using. We do NOT want to merge adjacent qualified rules with the same body
// if any of the selectors are unsafe, since then browsers which don't support
// that particular feature would ignore the entire merged qualified rule:
//
// Input:
// a { color: red }
// b { color: red }
// input::-moz-placeholder { color: red }
//
// Valid output:
// a, b { color: red }
// input::-moz-placeholder { color: red }
//
// Invalid output:
// a, b, input::-moz-placeholder { color: red }
//
// This considers IE 7 and above to be a browser that a user could possibly use.
// Versions of IE less than 6 are not considered.
func isSafeSelectors(complexSelectors []css_ast.ComplexSelector) bool {
for _, complex := range complexSelectors {
for _, compound := range complex.Selectors {
if compound.HasNestPrefix {
// Bail because this is an extension: https://drafts.csswg.org/css-nesting-1/
return false
}
if compound.Combinator != "" {
// "Before Internet Explorer 10, the combinator only works in standards mode"
// Reference: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors
return false
}
if compound.TypeSelector != nil {
if compound.TypeSelector.NamespacePrefix != nil {
// Bail if we hit a namespace, which doesn't work in IE before version 9
// Reference: https://developer.mozilla.org/en-US/docs/Web/CSS/Type_selectors
return false
}
if compound.TypeSelector.Name.Kind == css_lexer.TIdent && !nonDeprecatedElementsSupportedByIE7[compound.TypeSelector.Name.Text] {
// Bail if this element is either deprecated or not supported in IE 7
return false
}
}
for _, ss := range compound.SubclassSelectors {
switch s := ss.(type) {
case *css_ast.SSAttribute:
if s.MatcherModifier != 0 {
// Bail if we hit a case modifier, which doesn't work in IE at all
// Reference: https://developer.mozilla.org/en-US/docs/Web/CSS/Attribute_selectors
return false
}
case *css_ast.SSPseudoClass:
// Bail if this pseudo class doesn't match a hard-coded list that's
// known to work everywhere. For example, ":focus" doesn't work in IE 7.
// Reference: https://developer.mozilla.org/en-US/docs/Web/CSS/Pseudo-classes
if s.Args == nil && !s.IsElement {
switch s.Name {
case "active", "first-child", "hover", "link", "visited":
continue
}
}
return false
}
}
}
}
return true
}
func (p *parser) parseURLOrString() (string, logger.Range, bool) {
t := p.current()
switch t.Kind {
case css_lexer.TString:
text := p.decoded()
p.advance()
return text, t.Range, true
case css_lexer.TURL:
text := p.decoded()
p.advance()
return text, t.Range, true
case css_lexer.TFunction:
if p.decoded() == "url" {
p.advance()
t = p.current()
text := p.decoded()
if p.expect(css_lexer.TString) && p.expect(css_lexer.TCloseParen) {
return text, t.Range, true
}
}
}
return "", logger.Range{}, false
}
func (p *parser) expectURLOrString() (url string, r logger.Range, ok bool) {
url, r, ok = p.parseURLOrString()
if !ok {
p.expect(css_lexer.TURL)
}
return
}
type atRuleKind uint8
const (
atRuleUnknown atRuleKind = iota
atRuleDeclarations
atRuleInheritContext
atRuleEmpty
)
var specialAtRules = map[string]atRuleKind{
"font-face": atRuleDeclarations,
"page": atRuleDeclarations,
// These go inside "@page": https://www.w3.org/TR/css-page-3/#syntax-page-selector
"bottom-center": atRuleDeclarations,
"bottom-left-corner": atRuleDeclarations,
"bottom-left": atRuleDeclarations,
"bottom-right-corner": atRuleDeclarations,
"bottom-right": atRuleDeclarations,
"left-bottom": atRuleDeclarations,
"left-middle": atRuleDeclarations,
"left-top": atRuleDeclarations,
"right-bottom": atRuleDeclarations,
"right-middle": atRuleDeclarations,
"right-top": atRuleDeclarations,
"top-center": atRuleDeclarations,
"top-left-corner": atRuleDeclarations,
"top-left": atRuleDeclarations,
"top-right-corner": atRuleDeclarations,
"top-right": atRuleDeclarations,
// These properties are very deprecated and appear to only be useful for
// mobile versions of internet explorer (which may no longer exist?), but
// they are used by the https://ant.design/ design system so we recognize
// them to avoid the warning.
//
// Documentation: https://developer.mozilla.org/en-US/docs/Web/CSS/@viewport
// Discussion: https://github.com/w3c/csswg-drafts/issues/4766
//
"viewport": atRuleDeclarations,
"-ms-viewport": atRuleDeclarations,
// This feature has been removed from the web because it's actively harmful.
// However, there is one exception where "@-moz-document url-prefix() {" is
// accepted by Firefox to basically be an "if Firefox" conditional rule.
//
// Documentation: https://developer.mozilla.org/en-US/docs/Web/CSS/@document
// Discussion: https://bugzilla.mozilla.org/show_bug.cgi?id=1035091
//
"document": atRuleInheritContext,
"-moz-document": atRuleInheritContext,
"media": atRuleInheritContext,
"scope": atRuleInheritContext,
"supports": atRuleInheritContext,
}
type atRuleContext struct {
isDeclarationList bool
}
func (p *parser) parseAtRule(context atRuleContext) css_ast.Rule {
// Parse the name
atToken := p.decoded()
atRange := p.current().Range
kind := specialAtRules[atToken]
p.advance()
// Parse the prelude
preludeStart := p.index
switch atToken {
case "charset":
kind = atRuleEmpty
p.expect(css_lexer.TWhitespace)
if p.peek(css_lexer.TString) {
encoding := p.decoded()
if !strings.EqualFold(encoding, "UTF-8") {
p.log.AddRangeWarning(&p.tracker, p.current().Range,
fmt.Sprintf("\"UTF-8\" will be used instead of unsupported charset %q", encoding))
}
p.advance()
p.expect(css_lexer.TSemicolon)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RAtCharset{Encoding: encoding}}
}
p.expect(css_lexer.TString)
case "import":
kind = atRuleEmpty
p.eat(css_lexer.TWhitespace)
if path, r, ok := p.expectURLOrString(); ok {
importConditionsStart := p.index
for p.current().Kind != css_lexer.TSemicolon && p.current().Kind != css_lexer.TEndOfFile {
p.parseComponentValue()
}
importConditions := p.convertTokens(p.tokens[importConditionsStart:p.index])
kind := ast.ImportAt
// Insert or remove whitespace before the first token
if len(importConditions) > 0 {
kind = ast.ImportAtConditional
if p.options.RemoveWhitespace {
importConditions[0].Whitespace &= ^css_ast.WhitespaceBefore
} else {
importConditions[0].Whitespace |= css_ast.WhitespaceBefore
}
}
p.expect(css_lexer.TSemicolon)
importRecordIndex := uint32(len(p.importRecords))
p.importRecords = append(p.importRecords, ast.ImportRecord{
Kind: kind,
Path: logger.Path{Text: path},
Range: r,
})
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RAtImport{
ImportRecordIndex: importRecordIndex,
ImportConditions: importConditions,
}}
}
case "keyframes", "-webkit-keyframes", "-moz-keyframes", "-ms-keyframes", "-o-keyframes":
p.eat(css_lexer.TWhitespace)
var name string
if p.peek(css_lexer.TIdent) {
name = p.decoded()
p.advance()
} else if !p.expect(css_lexer.TIdent) && !p.eat(css_lexer.TString) && !p.peek(css_lexer.TOpenBrace) {
// Consider string names a syntax error even though they are allowed by
// the specification and they work in Firefox because they do not work in
// Chrome or Safari.
break
}
p.eat(css_lexer.TWhitespace)
if p.expect(css_lexer.TOpenBrace) {
var blocks []css_ast.KeyframeBlock
blocks:
for {
switch p.current().Kind {
case css_lexer.TWhitespace:
p.advance()
continue
case css_lexer.TCloseBrace, css_lexer.TEndOfFile:
break blocks
case css_lexer.TOpenBrace:
p.expect(css_lexer.TPercentage)
p.parseComponentValue()
default:
var selectors []string
selectors:
for {
t := p.current()
switch t.Kind {
case css_lexer.TWhitespace:
p.advance()
continue
case css_lexer.TOpenBrace, css_lexer.TEndOfFile:
break selectors
case css_lexer.TIdent, css_lexer.TPercentage:
text := p.decoded()
if t.Kind == css_lexer.TIdent {
if text == "from" {
if p.options.MangleSyntax {
text = "0%" // "0%" is equivalent to but shorter than "from"
}
} else if text != "to" {
p.expect(css_lexer.TPercentage)
}
} else if p.options.MangleSyntax && text == "100%" {
text = "to" // "to" is equivalent to but shorter than "100%"
}
selectors = append(selectors, text)
p.advance()
default:
p.expect(css_lexer.TPercentage)
p.parseComponentValue()
}
p.eat(css_lexer.TWhitespace)
if t.Kind != css_lexer.TComma && !p.peek(css_lexer.TOpenBrace) {
p.expect(css_lexer.TComma)
}
}
if p.expect(css_lexer.TOpenBrace) {
rules := p.parseListOfDeclarations()
p.expect(css_lexer.TCloseBrace)
// "@keyframes { from {} to { color: red } }" => "@keyframes { to { color: red } }"
if !p.options.MangleSyntax || len(rules) > 0 {
blocks = append(blocks, css_ast.KeyframeBlock{
Selectors: selectors,
Rules: rules,
})
}
}
}
}
p.expect(css_lexer.TCloseBrace)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RAtKeyframes{
AtToken: atToken,
Name: name,
Blocks: blocks,
}}
}
default:
if kind == atRuleUnknown && atToken == "namespace" {
// CSS namespaces are a weird feature that appears to only really be
// useful for styling XML. And the world has moved on from XHTML to
// HTML5 so pretty much no one uses CSS namespaces anymore. They are
// also complicated to support in a bundler because CSS namespaces are
// file-scoped, which means:
//
// * Default namespaces can be different in different files, in which
// case some default namespaces would have to be converted to prefixed
// namespaces to avoid collisions.
//
// * Prefixed namespaces from different files can use the same name, in
// which case some prefixed namespaces would need to be renamed to
// avoid collisions.
//
// Instead of implementing all of that for an extremely obscure feature,
// CSS namespaces are just explicitly not supported.
p.log.AddRangeWarning(&p.tracker, atRange, "\"@namespace\" rules are not supported")
}
}
// Parse an unknown prelude
prelude:
for {
switch p.current().Kind {
case css_lexer.TOpenBrace, css_lexer.TEndOfFile:
break prelude
case css_lexer.TSemicolon, css_lexer.TCloseBrace:
prelude := p.convertTokens(p.tokens[preludeStart:p.index])
// Report an error for rules that should have blocks
if kind != atRuleEmpty && kind != atRuleUnknown {
p.expect(css_lexer.TOpenBrace)
p.eat(css_lexer.TSemicolon)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RUnknownAt{AtToken: atToken, Prelude: prelude}}
}
// Otherwise, parse an unknown at rule
p.expect(css_lexer.TSemicolon)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RUnknownAt{AtToken: atToken, Prelude: prelude}}
default:
p.parseComponentValue()
}
}
prelude := p.convertTokens(p.tokens[preludeStart:p.index])
blockStart := p.index
switch kind {
case atRuleEmpty:
// Report an error for rules that shouldn't have blocks
p.expect(css_lexer.TSemicolon)
p.parseBlock(css_lexer.TOpenBrace, css_lexer.TCloseBrace)
block := p.convertTokens(p.tokens[blockStart:p.index])
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RUnknownAt{AtToken: atToken, Prelude: prelude, Block: block}}
case atRuleDeclarations:
// Parse known rules whose blocks consist of whatever the current context is
p.advance()
rules := p.parseListOfDeclarations()
p.expect(css_lexer.TCloseBrace)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RKnownAt{AtToken: atToken, Prelude: prelude, Rules: rules}}
case atRuleInheritContext:
// Parse known rules whose blocks consist of whatever the current context is
p.advance()
var rules []css_ast.Rule
if context.isDeclarationList {
rules = p.parseListOfDeclarations()
} else {
rules = p.parseListOfRules(ruleContext{
parseSelectors: true,
})
}
p.expect(css_lexer.TCloseBrace)
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RKnownAt{AtToken: atToken, Prelude: prelude, Rules: rules}}
default:
// Otherwise, parse an unknown rule
p.parseBlock(css_lexer.TOpenBrace, css_lexer.TCloseBrace)
block, _ := p.convertTokensHelper(p.tokens[blockStart:p.index], css_lexer.TEndOfFile, convertTokensOpts{allowImports: true})
return css_ast.Rule{Loc: atRange.Loc, Data: &css_ast.RUnknownAt{AtToken: atToken, Prelude: prelude, Block: block}}
}
}
func (p *parser) convertTokens(tokens []css_lexer.Token) []css_ast.Token {
result, _ := p.convertTokensHelper(tokens, css_lexer.TEndOfFile, convertTokensOpts{})
return result
}
type convertTokensOpts struct {
allowImports bool
verbatimWhitespace bool
isInsideCalcFunction bool
}
func (p *parser) convertTokensHelper(tokens []css_lexer.Token, close css_lexer.T, opts convertTokensOpts) ([]css_ast.Token, []css_lexer.Token) {
var result []css_ast.Token
var nextWhitespace css_ast.WhitespaceFlags
loop:
for len(tokens) > 0 {
t := tokens[0]
tokens = tokens[1:]
if t.Kind == close {
break loop
}
token := css_ast.Token{
Kind: t.Kind,
Text: t.DecodedText(p.source.Contents),
Whitespace: nextWhitespace,
}
nextWhitespace = 0
// Warn about invalid "+" and "-" operators that break the containing "calc()"
if opts.isInsideCalcFunction && t.Kind.IsNumeric() && len(result) > 0 && result[len(result)-1].Kind.IsNumeric() &&
(strings.HasPrefix(token.Text, "+") || strings.HasPrefix(token.Text, "-")) {
// "calc(1+2)" and "calc(1-2)" are invalid
p.log.AddRangeWarning(&p.tracker, logger.Range{Loc: t.Range.Loc, Len: 1},
fmt.Sprintf("The %q operator only works if there is whitespace on both sides", token.Text[:1]))
}
switch t.Kind {
case css_lexer.TWhitespace:
if last := len(result) - 1; last >= 0 {
result[last].Whitespace |= css_ast.WhitespaceAfter
}
nextWhitespace = css_ast.WhitespaceBefore
continue
case css_lexer.TDelimPlus, css_lexer.TDelimMinus:
// Warn about invalid "+" and "-" operators that break the containing "calc()"
if opts.isInsideCalcFunction && len(tokens) > 0 {
if len(result) == 0 || result[len(result)-1].Kind == css_lexer.TComma {
// "calc(-(1 + 2))" is invalid
p.log.AddRangeWarning(&p.tracker, t.Range,
fmt.Sprintf("%q can only be used as an infix operator, not a prefix operator", token.Text))
} else if token.Whitespace != css_ast.WhitespaceBefore || tokens[0].Kind != css_lexer.TWhitespace {
// "calc(1- 2)" and "calc(1 -(2))" are invalid
p.log.AddRangeWarning(&p.tracker, t.Range,
fmt.Sprintf("The %q operator only works if there is whitespace on both sides", token.Text))
}
}
case css_lexer.TNumber:
if p.options.MangleSyntax {
if text, ok := mangleNumber(token.Text); ok {
token.Text = text
}
}
case css_lexer.TPercentage:
if p.options.MangleSyntax {
if text, ok := mangleNumber(token.PercentageValue()); ok {
token.Text = text + "%"
}
}
case css_lexer.TDimension:
token.UnitOffset = t.UnitOffset
if p.options.MangleSyntax {
if text, ok := mangleNumber(token.DimensionValue()); ok {
token.Text = text + token.DimensionUnit()
token.UnitOffset = uint16(len(text))
}
if value, unit, ok := mangleDimension(token.DimensionValue(), token.DimensionUnit()); ok {
token.Text = value + unit
token.UnitOffset = uint16(len(value))
}
}
case css_lexer.TURL:
token.ImportRecordIndex = uint32(len(p.importRecords))
p.importRecords = append(p.importRecords, ast.ImportRecord{
Kind: ast.ImportURL,
Path: logger.Path{Text: token.Text},
Range: t.Range,
IsUnused: !opts.allowImports,
})
token.Text = ""
case css_lexer.TFunction:
var nested []css_ast.Token
original := tokens
nestedOpts := opts
if token.Text == "var" {
// CSS variables require verbatim whitespace for correctness
nestedOpts.verbatimWhitespace = true
}
if token.Text == "calc" {
nestedOpts.isInsideCalcFunction = true
}
nested, tokens = p.convertTokensHelper(tokens, css_lexer.TCloseParen, nestedOpts)
token.Children = &nested
// Apply "calc" simplification rules when minifying
if p.options.MangleSyntax && token.Text == "calc" {
token = p.tryToReduceCalcExpression(token)
}
// Treat a URL function call with a string just like a URL token
if token.Text == "url" && len(nested) == 1 && nested[0].Kind == css_lexer.TString {
token.Kind = css_lexer.TURL
token.Text = ""
token.Children = nil
token.ImportRecordIndex = uint32(len(p.importRecords))
p.importRecords = append(p.importRecords, ast.ImportRecord{
Kind: ast.ImportURL,
Path: logger.Path{Text: nested[0].Text},
Range: original[0].Range,
IsUnused: !opts.allowImports,
})
}
case css_lexer.TOpenParen:
var nested []css_ast.Token
nested, tokens = p.convertTokensHelper(tokens, css_lexer.TCloseParen, opts)
token.Children = &nested
case css_lexer.TOpenBrace:
var nested []css_ast.Token
nested, tokens = p.convertTokensHelper(tokens, css_lexer.TCloseBrace, opts)