mirror of
https://github.com/miniflux/v2.git
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560 lines
16 KiB
Go
560 lines
16 KiB
Go
// Package css minifies CSS3 following the specifications at http://www.w3.org/TR/css-syntax-3/.
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package css // import "github.com/tdewolff/minify/css"
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import (
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"bytes"
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"encoding/hex"
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"io"
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"strconv"
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"github.com/tdewolff/minify"
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"github.com/tdewolff/parse"
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"github.com/tdewolff/parse/css"
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)
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var (
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spaceBytes = []byte(" ")
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colonBytes = []byte(":")
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semicolonBytes = []byte(";")
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commaBytes = []byte(",")
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leftBracketBytes = []byte("{")
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rightBracketBytes = []byte("}")
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zeroBytes = []byte("0")
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msfilterBytes = []byte("-ms-filter")
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backgroundNoneBytes = []byte("0 0")
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)
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type cssMinifier struct {
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m *minify.M
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w io.Writer
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p *css.Parser
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o *Minifier
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}
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////////////////////////////////////////////////////////////////
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// DefaultMinifier is the default minifier.
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var DefaultMinifier = &Minifier{Decimals: -1}
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// Minifier is a CSS minifier.
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type Minifier struct {
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Decimals int
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}
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// Minify minifies CSS data, it reads from r and writes to w.
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func Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
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return DefaultMinifier.Minify(m, w, r, params)
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}
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// Minify minifies CSS data, it reads from r and writes to w.
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func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, params map[string]string) error {
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isInline := params != nil && params["inline"] == "1"
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c := &cssMinifier{
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m: m,
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w: w,
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p: css.NewParser(r, isInline),
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o: o,
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}
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defer c.p.Restore()
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if err := c.minifyGrammar(); err != nil && err != io.EOF {
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return err
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}
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return nil
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}
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func (c *cssMinifier) minifyGrammar() error {
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semicolonQueued := false
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for {
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gt, _, data := c.p.Next()
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if gt == css.ErrorGrammar {
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if perr, ok := c.p.Err().(*parse.Error); ok && perr.Message == "unexpected token in declaration" {
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if semicolonQueued {
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if _, err := c.w.Write(semicolonBytes); err != nil {
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return err
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}
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}
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// write out the offending declaration
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if _, err := c.w.Write(data); err != nil {
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return err
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}
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for _, val := range c.p.Values() {
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if _, err := c.w.Write(val.Data); err != nil {
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return err
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}
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}
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semicolonQueued = true
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continue
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} else {
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return c.p.Err()
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}
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} else if gt == css.EndAtRuleGrammar || gt == css.EndRulesetGrammar {
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if _, err := c.w.Write(rightBracketBytes); err != nil {
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return err
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}
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semicolonQueued = false
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continue
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}
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if semicolonQueued {
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if _, err := c.w.Write(semicolonBytes); err != nil {
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return err
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}
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semicolonQueued = false
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}
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if gt == css.AtRuleGrammar {
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if _, err := c.w.Write(data); err != nil {
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return err
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}
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for _, val := range c.p.Values() {
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if _, err := c.w.Write(val.Data); err != nil {
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return err
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}
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}
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semicolonQueued = true
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} else if gt == css.BeginAtRuleGrammar {
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if _, err := c.w.Write(data); err != nil {
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return err
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}
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for _, val := range c.p.Values() {
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if _, err := c.w.Write(val.Data); err != nil {
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return err
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}
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}
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if _, err := c.w.Write(leftBracketBytes); err != nil {
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return err
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}
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} else if gt == css.QualifiedRuleGrammar {
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if err := c.minifySelectors(data, c.p.Values()); err != nil {
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return err
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}
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if _, err := c.w.Write(commaBytes); err != nil {
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return err
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}
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} else if gt == css.BeginRulesetGrammar {
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if err := c.minifySelectors(data, c.p.Values()); err != nil {
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return err
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}
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if _, err := c.w.Write(leftBracketBytes); err != nil {
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return err
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}
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} else if gt == css.DeclarationGrammar {
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if _, err := c.w.Write(data); err != nil {
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return err
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}
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if _, err := c.w.Write(colonBytes); err != nil {
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return err
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}
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if err := c.minifyDeclaration(data, c.p.Values()); err != nil {
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return err
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}
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semicolonQueued = true
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} else if gt == css.CustomPropertyGrammar {
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if _, err := c.w.Write(data); err != nil {
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return err
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}
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if _, err := c.w.Write(colonBytes); err != nil {
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return err
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}
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if _, err := c.w.Write(c.p.Values()[0].Data); err != nil {
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return err
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}
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semicolonQueued = true
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} else if gt == css.CommentGrammar {
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if len(data) > 5 && data[1] == '*' && data[2] == '!' {
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if _, err := c.w.Write(data[:3]); err != nil {
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return err
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}
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comment := parse.TrimWhitespace(parse.ReplaceMultipleWhitespace(data[3 : len(data)-2]))
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if _, err := c.w.Write(comment); err != nil {
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return err
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}
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if _, err := c.w.Write(data[len(data)-2:]); err != nil {
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return err
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}
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}
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} else if _, err := c.w.Write(data); err != nil {
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return err
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}
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}
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}
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func (c *cssMinifier) minifySelectors(property []byte, values []css.Token) error {
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inAttr := false
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isClass := false
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for _, val := range c.p.Values() {
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if !inAttr {
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if val.TokenType == css.IdentToken {
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if !isClass {
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parse.ToLower(val.Data)
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}
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isClass = false
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} else if val.TokenType == css.DelimToken && val.Data[0] == '.' {
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isClass = true
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} else if val.TokenType == css.LeftBracketToken {
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inAttr = true
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}
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} else {
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if val.TokenType == css.StringToken && len(val.Data) > 2 {
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s := val.Data[1 : len(val.Data)-1]
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if css.IsIdent([]byte(s)) {
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if _, err := c.w.Write(s); err != nil {
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return err
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}
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continue
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}
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} else if val.TokenType == css.RightBracketToken {
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inAttr = false
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}
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}
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if _, err := c.w.Write(val.Data); err != nil {
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return err
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}
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}
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return nil
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}
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func (c *cssMinifier) minifyDeclaration(property []byte, values []css.Token) error {
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if len(values) == 0 {
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return nil
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}
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prop := css.ToHash(property)
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inProgid := false
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for i, value := range values {
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if inProgid {
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if value.TokenType == css.FunctionToken {
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inProgid = false
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}
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continue
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} else if value.TokenType == css.IdentToken && css.ToHash(value.Data) == css.Progid {
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inProgid = true
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continue
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}
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value.TokenType, value.Data = c.shortenToken(prop, value.TokenType, value.Data)
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if prop == css.Font || prop == css.Font_Family || prop == css.Font_Weight {
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if value.TokenType == css.IdentToken && (prop == css.Font || prop == css.Font_Weight) {
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val := css.ToHash(value.Data)
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if val == css.Normal && prop == css.Font_Weight {
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// normal could also be specified for font-variant, not just font-weight
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value.TokenType = css.NumberToken
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value.Data = []byte("400")
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} else if val == css.Bold {
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value.TokenType = css.NumberToken
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value.Data = []byte("700")
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}
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} else if value.TokenType == css.StringToken && (prop == css.Font || prop == css.Font_Family) && len(value.Data) > 2 {
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unquote := true
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parse.ToLower(value.Data)
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s := value.Data[1 : len(value.Data)-1]
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if len(s) > 0 {
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for _, split := range bytes.Split(s, spaceBytes) {
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val := css.ToHash(split)
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// if len is zero, it contains two consecutive spaces
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if val == css.Inherit || val == css.Serif || val == css.Sans_Serif || val == css.Monospace || val == css.Fantasy || val == css.Cursive || val == css.Initial || val == css.Default ||
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len(split) == 0 || !css.IsIdent(split) {
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unquote = false
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break
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}
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}
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}
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if unquote {
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value.Data = s
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}
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}
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} else if prop == css.Outline || prop == css.Border || prop == css.Border_Bottom || prop == css.Border_Left || prop == css.Border_Right || prop == css.Border_Top {
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if css.ToHash(value.Data) == css.None {
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value.TokenType = css.NumberToken
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value.Data = zeroBytes
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}
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}
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values[i].TokenType, values[i].Data = value.TokenType, value.Data
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}
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important := false
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if len(values) > 2 && values[len(values)-2].TokenType == css.DelimToken && values[len(values)-2].Data[0] == '!' && css.ToHash(values[len(values)-1].Data) == css.Important {
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values = values[:len(values)-2]
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important = true
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}
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if len(values) == 1 {
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if prop == css.Background && css.ToHash(values[0].Data) == css.None {
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values[0].Data = backgroundNoneBytes
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} else if bytes.Equal(property, msfilterBytes) {
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alpha := []byte("progid:DXImageTransform.Microsoft.Alpha(Opacity=")
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if values[0].TokenType == css.StringToken && bytes.HasPrefix(values[0].Data[1:len(values[0].Data)-1], alpha) {
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values[0].Data = append(append([]byte{values[0].Data[0]}, []byte("alpha(opacity=")...), values[0].Data[1+len(alpha):]...)
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}
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}
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} else {
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if prop == css.Margin || prop == css.Padding || prop == css.Border_Width {
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if (values[0].TokenType == css.NumberToken || values[0].TokenType == css.DimensionToken || values[0].TokenType == css.PercentageToken) && (len(values)+1)%2 == 0 {
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valid := true
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for i := 1; i < len(values); i += 2 {
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if values[i].TokenType != css.WhitespaceToken || values[i+1].TokenType != css.NumberToken && values[i+1].TokenType != css.DimensionToken && values[i+1].TokenType != css.PercentageToken {
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valid = false
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break
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}
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}
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if valid {
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n := (len(values) + 1) / 2
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if n == 2 {
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if bytes.Equal(values[0].Data, values[2].Data) {
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values = values[:1]
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}
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} else if n == 3 {
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if bytes.Equal(values[0].Data, values[2].Data) && bytes.Equal(values[0].Data, values[4].Data) {
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values = values[:1]
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} else if bytes.Equal(values[0].Data, values[4].Data) {
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values = values[:3]
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}
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} else if n == 4 {
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if bytes.Equal(values[0].Data, values[2].Data) && bytes.Equal(values[0].Data, values[4].Data) && bytes.Equal(values[0].Data, values[6].Data) {
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values = values[:1]
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} else if bytes.Equal(values[0].Data, values[4].Data) && bytes.Equal(values[2].Data, values[6].Data) {
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values = values[:3]
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} else if bytes.Equal(values[2].Data, values[6].Data) {
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values = values[:5]
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}
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}
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}
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}
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} else if prop == css.Filter && len(values) == 11 {
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if bytes.Equal(values[0].Data, []byte("progid")) &&
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values[1].TokenType == css.ColonToken &&
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bytes.Equal(values[2].Data, []byte("DXImageTransform")) &&
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values[3].Data[0] == '.' &&
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bytes.Equal(values[4].Data, []byte("Microsoft")) &&
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values[5].Data[0] == '.' &&
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bytes.Equal(values[6].Data, []byte("Alpha(")) &&
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bytes.Equal(parse.ToLower(values[7].Data), []byte("opacity")) &&
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values[8].Data[0] == '=' &&
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values[10].Data[0] == ')' {
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values = values[6:]
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values[0].Data = []byte("alpha(")
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}
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}
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}
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for i := 0; i < len(values); i++ {
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if values[i].TokenType == css.FunctionToken {
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n, err := c.minifyFunction(values[i:])
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if err != nil {
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return err
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}
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i += n - 1
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} else if _, err := c.w.Write(values[i].Data); err != nil {
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return err
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}
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}
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if important {
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if _, err := c.w.Write([]byte("!important")); err != nil {
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return err
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}
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}
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return nil
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}
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func (c *cssMinifier) minifyFunction(values []css.Token) (int, error) {
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n := 1
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simple := true
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for i, value := range values[1:] {
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if value.TokenType == css.RightParenthesisToken {
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n++
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break
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}
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if i%2 == 0 && (value.TokenType != css.NumberToken && value.TokenType != css.PercentageToken) || (i%2 == 1 && value.TokenType != css.CommaToken) {
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simple = false
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}
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n++
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}
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values = values[:n]
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if simple && (n-1)%2 == 0 {
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fun := css.ToHash(values[0].Data[:len(values[0].Data)-1])
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nArgs := (n - 1) / 2
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if (fun == css.Rgba || fun == css.Hsla) && nArgs == 4 {
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d, _ := strconv.ParseFloat(string(values[7].Data), 32) // can never fail because if simple == true than this is a NumberToken or PercentageToken
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if d-1.0 > -minify.Epsilon {
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if fun == css.Rgba {
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values[0].Data = []byte("rgb(")
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fun = css.Rgb
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} else {
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values[0].Data = []byte("hsl(")
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fun = css.Hsl
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}
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values = values[:len(values)-2]
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values[len(values)-1].Data = []byte(")")
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nArgs = 3
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} else if d < minify.Epsilon {
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values[0].Data = []byte("transparent")
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values = values[:1]
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fun = 0
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nArgs = 0
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}
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}
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if fun == css.Rgb && nArgs == 3 {
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var err [3]error
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rgb := [3]byte{}
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for j := 0; j < 3; j++ {
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val := values[j*2+1]
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if val.TokenType == css.NumberToken {
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var d int64
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d, err[j] = strconv.ParseInt(string(val.Data), 10, 32)
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if d < 0 {
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d = 0
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} else if d > 255 {
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d = 255
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}
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rgb[j] = byte(d)
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} else if val.TokenType == css.PercentageToken {
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var d float64
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d, err[j] = strconv.ParseFloat(string(val.Data[:len(val.Data)-1]), 32)
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if d < 0.0 {
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d = 0.0
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} else if d > 100.0 {
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d = 100.0
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}
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rgb[j] = byte((d / 100.0 * 255.0) + 0.5)
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}
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}
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if err[0] == nil && err[1] == nil && err[2] == nil {
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val := make([]byte, 7)
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val[0] = '#'
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hex.Encode(val[1:], rgb[:])
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parse.ToLower(val)
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if s, ok := ShortenColorHex[string(val)]; ok {
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if _, err := c.w.Write(s); err != nil {
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return 0, err
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}
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} else {
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if len(val) == 7 && val[1] == val[2] && val[3] == val[4] && val[5] == val[6] {
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val[2] = val[3]
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val[3] = val[5]
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val = val[:4]
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}
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if _, err := c.w.Write(val); err != nil {
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return 0, err
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}
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}
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return n, nil
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}
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} else if fun == css.Hsl && nArgs == 3 {
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if values[1].TokenType == css.NumberToken && values[3].TokenType == css.PercentageToken && values[5].TokenType == css.PercentageToken {
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h, err1 := strconv.ParseFloat(string(values[1].Data), 32)
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s, err2 := strconv.ParseFloat(string(values[3].Data[:len(values[3].Data)-1]), 32)
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l, err3 := strconv.ParseFloat(string(values[5].Data[:len(values[5].Data)-1]), 32)
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if err1 == nil && err2 == nil && err3 == nil {
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r, g, b := css.HSL2RGB(h/360.0, s/100.0, l/100.0)
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rgb := []byte{byte((r * 255.0) + 0.5), byte((g * 255.0) + 0.5), byte((b * 255.0) + 0.5)}
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val := make([]byte, 7)
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val[0] = '#'
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hex.Encode(val[1:], rgb[:])
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parse.ToLower(val)
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if s, ok := ShortenColorHex[string(val)]; ok {
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if _, err := c.w.Write(s); err != nil {
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return 0, err
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}
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} else {
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if len(val) == 7 && val[1] == val[2] && val[3] == val[4] && val[5] == val[6] {
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val[2] = val[3]
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val[3] = val[5]
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val = val[:4]
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}
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if _, err := c.w.Write(val); err != nil {
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return 0, err
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}
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}
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return n, nil
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}
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}
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}
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}
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for _, value := range values {
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if _, err := c.w.Write(value.Data); err != nil {
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return 0, err
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}
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}
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return n, nil
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}
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|
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func (c *cssMinifier) shortenToken(prop css.Hash, tt css.TokenType, data []byte) (css.TokenType, []byte) {
|
|
if tt == css.NumberToken || tt == css.PercentageToken || tt == css.DimensionToken {
|
|
if tt == css.NumberToken && (prop == css.Z_Index || prop == css.Counter_Increment || prop == css.Counter_Reset || prop == css.Orphans || prop == css.Widows) {
|
|
return tt, data // integers
|
|
}
|
|
n := len(data)
|
|
if tt == css.PercentageToken {
|
|
n--
|
|
} else if tt == css.DimensionToken {
|
|
n = parse.Number(data)
|
|
}
|
|
dim := data[n:]
|
|
parse.ToLower(dim)
|
|
data = minify.Number(data[:n], c.o.Decimals)
|
|
if tt == css.PercentageToken && (len(data) != 1 || data[0] != '0' || prop == css.Color) {
|
|
data = append(data, '%')
|
|
} else if tt == css.DimensionToken && (len(data) != 1 || data[0] != '0' || requiredDimension[string(dim)]) {
|
|
data = append(data, dim...)
|
|
}
|
|
} else if tt == css.IdentToken {
|
|
//parse.ToLower(data) // TODO: not all identifiers are case-insensitive; all <custom-ident> properties are case-sensitive
|
|
if hex, ok := ShortenColorName[css.ToHash(data)]; ok {
|
|
tt = css.HashToken
|
|
data = hex
|
|
}
|
|
} else if tt == css.HashToken {
|
|
parse.ToLower(data)
|
|
if ident, ok := ShortenColorHex[string(data)]; ok {
|
|
tt = css.IdentToken
|
|
data = ident
|
|
} else if len(data) == 7 && data[1] == data[2] && data[3] == data[4] && data[5] == data[6] {
|
|
tt = css.HashToken
|
|
data[2] = data[3]
|
|
data[3] = data[5]
|
|
data = data[:4]
|
|
}
|
|
} else if tt == css.StringToken {
|
|
// remove any \\\r\n \\\r \\\n
|
|
for i := 1; i < len(data)-2; i++ {
|
|
if data[i] == '\\' && (data[i+1] == '\n' || data[i+1] == '\r') {
|
|
// encountered first replacee, now start to move bytes to the front
|
|
j := i + 2
|
|
if data[i+1] == '\r' && len(data) > i+2 && data[i+2] == '\n' {
|
|
j++
|
|
}
|
|
for ; j < len(data); j++ {
|
|
if data[j] == '\\' && len(data) > j+1 && (data[j+1] == '\n' || data[j+1] == '\r') {
|
|
if data[j+1] == '\r' && len(data) > j+2 && data[j+2] == '\n' {
|
|
j++
|
|
}
|
|
j++
|
|
} else {
|
|
data[i] = data[j]
|
|
i++
|
|
}
|
|
}
|
|
data = data[:i]
|
|
break
|
|
}
|
|
}
|
|
} else if tt == css.URLToken {
|
|
parse.ToLower(data[:3])
|
|
if len(data) > 10 {
|
|
uri := data[4 : len(data)-1]
|
|
delim := byte('"')
|
|
if uri[0] == '\'' || uri[0] == '"' {
|
|
delim = uri[0]
|
|
uri = uri[1 : len(uri)-1]
|
|
}
|
|
uri = minify.DataURI(c.m, uri)
|
|
if css.IsURLUnquoted(uri) {
|
|
data = append(append([]byte("url("), uri...), ')')
|
|
} else {
|
|
data = append(append(append([]byte("url("), delim), uri...), delim, ')')
|
|
}
|
|
}
|
|
}
|
|
return tt, data
|
|
}
|