Exemplo n.º 1
0
// Minify minifies HTML data, it reads from r and writes to w.
func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
	var rawTagHash html.Hash
	var rawTagTraits traits
	var rawTagMediatype []byte
	omitSpace := true // if true the next leading space is omitted
	defaultScriptType := jsMimeBytes
	defaultScriptParams := map[string]string(nil)
	defaultStyleType := cssMimeBytes
	defaultStyleParams := map[string]string(nil)
	defaultInlineStyleParams := map[string]string{"inline": "1"}

	attrMinifyBuffer := buffer.NewWriter(make([]byte, 0, 64))
	attrByteBuffer := make([]byte, 0, 64)
	attrTokenBuffer := make([]*Token, 0, maxAttrLookup)

	l := html.NewLexer(r)
	tb := NewTokenBuffer(l)
	for {
		t := *tb.Shift()
	SWITCH:
		switch t.TokenType {
		case html.ErrorToken:
			if l.Err() == io.EOF {
				return nil
			}
			return l.Err()
		case html.DoctypeToken:
			if _, err := w.Write([]byte("<!doctype html>")); err != nil {
				return err
			}
		case html.CommentToken:
			// TODO: ensure that nested comments are handled properly (lexer doesn't handle this!)
			var comment []byte
			if bytes.HasPrefix(t.Data, []byte("[if")) {
				comment = append(append([]byte("<!--"), t.Data...), []byte("-->")...)
			} else if bytes.HasSuffix(t.Data, []byte("--")) {
				// only occurs when mixed up with conditional comments
				comment = append(append([]byte("<!"), t.Data...), '>')
			}
			if _, err := w.Write(comment); err != nil {
				return err
			}
		case html.TextToken:
			// CSS and JS minifiers for inline code
			if rawTagHash != 0 {
				if rawTagHash == html.Style || rawTagHash == html.Script || rawTagHash == html.Iframe || rawTagHash == html.Svg || rawTagHash == html.Math {
					var mimetype []byte
					var params map[string]string
					if rawTagHash == html.Iframe {
						mimetype = htmlMimeBytes
					} else if rawTagHash == html.Svg {
						mimetype = svgMimeBytes
					} else if rawTagHash == html.Math {
						mimetype = mathMimeBytes
					} else if len(rawTagMediatype) > 0 {
						mimetype, params = parse.Mediatype(rawTagMediatype)
					} else if rawTagHash == html.Script {
						mimetype = defaultScriptType
						params = defaultScriptParams
					} else if rawTagHash == html.Style {
						mimetype = defaultStyleType
						params = defaultStyleParams
					}
					// TODO: really necessary?
					// ignore CDATA because that only has meaning in XML
					if trimmedData := parse.TrimWhitespace(t.Data); len(trimmedData) > 12 && bytes.Equal(trimmedData[:9], cdataBytes) && bytes.Equal(trimmedData[len(trimmedData)-3:], cdataEndBytes) {
						t.Data = trimmedData[9 : len(trimmedData)-3]
					}
					if err := m.MinifyMimetype(mimetype, w, buffer.NewReader(t.Data), params); err != nil {
						if _, err := w.Write(t.Data); err != nil {
							return err
						}
					}
				} else if _, err := w.Write(t.Data); err != nil {
					return err
				}
				if rawTagTraits&nonPhrasingTag == 0 && rawTagHash != html.Script {
					omitSpace = len(t.Data) > 0 && t.Data[len(t.Data)-1] == ' '
				}
			} else {
				t.Data = parse.ReplaceMultipleWhitespace(t.Data)
				if !o.KeepWhitespace {
					// whitespace removal; trim left
					if omitSpace && t.Data[0] == ' ' {
						t.Data = t.Data[1:]
					}

					// whitespace removal; trim right
					omitSpace = false
					if len(t.Data) == 0 {
						omitSpace = true
					} else if t.Data[len(t.Data)-1] == ' ' {
						omitSpace = true
						i := 0
						for {
							next := tb.Peek(i)
							// trim if EOF, text token with leading whitespace or block token
							if next.TokenType == html.ErrorToken {
								t.Data = t.Data[:len(t.Data)-1]
								omitSpace = false
								break
							} else if next.TokenType == html.TextToken {
								// remove if the text token starts with a whitespace
								if len(next.Data) > 0 && parse.IsWhitespace(next.Data[0]) {
									t.Data = t.Data[:len(t.Data)-1]
									omitSpace = false
								}
								break
							} else if next.TokenType == html.StartTagToken || next.TokenType == html.EndTagToken {
								// remove when followed up by a block tag
								if next.Traits&nonPhrasingTag != 0 {
									t.Data = t.Data[:len(t.Data)-1]
									omitSpace = false
									break
								} else if next.TokenType == html.StartTagToken {
									break
								}
							}
							i++
						}
					}
				}
				if _, err := w.Write(t.Data); err != nil {
					return err
				}
			}
		case html.StartTagToken, html.EndTagToken:
			rawTagHash = 0
			hasAttributes := false
			if t.TokenType == html.StartTagToken {
				if next := tb.Peek(0); next.TokenType == html.AttributeToken {
					hasAttributes = true
				}
				if t.Traits&rawTag != 0 {
					// ignore empty script and style tags
					if !hasAttributes && (t.Hash == html.Script || t.Hash == html.Style) {
						if next := tb.Peek(1); next.TokenType == html.EndTagToken {
							tb.Shift()
							tb.Shift()
							break
						}
					}
					rawTagHash = t.Hash
					rawTagTraits = t.Traits
					rawTagMediatype = nil
				}
			}
			if t.Traits&nonPhrasingTag != 0 {
				omitSpace = true // omit spaces after block elements
			}

			// remove superfluous ending tags
			if !hasAttributes && (t.Hash == html.Html || t.Hash == html.Head || t.Hash == html.Body || t.Hash == html.Colgroup) {
				break
			} else if t.TokenType == html.EndTagToken {
				if t.Hash == html.Thead || t.Hash == html.Tbody || t.Hash == html.Tfoot || t.Hash == html.Tr || t.Hash == html.Th || t.Hash == html.Td ||
					t.Hash == html.Optgroup || t.Hash == html.Option || t.Hash == html.Dd || t.Hash == html.Dt ||
					t.Hash == html.Li || t.Hash == html.Rb || t.Hash == html.Rt || t.Hash == html.Rtc || t.Hash == html.Rp {
					break
				} else if t.Hash == html.P {
					i := 0
					for {
						next := tb.Peek(i)
						i++
						// continue if text token is empty or whitespace
						if next.TokenType == html.TextToken && parse.IsAllWhitespace(next.Data) {
							continue
						}
						if next.TokenType == html.ErrorToken || next.TokenType == html.EndTagToken && next.Hash != html.A || next.TokenType == html.StartTagToken && next.Traits&nonPhrasingTag != 0 {
							break SWITCH
						}
						break
					}
				}
			}

			// write tag
			if t.TokenType == html.EndTagToken {
				if _, err := w.Write(endBytes); err != nil {
					return err
				}
			} else {
				if _, err := w.Write(ltBytes); err != nil {
					return err
				}
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}

			if hasAttributes {
				// rewrite attributes with interdependent conditions
				if t.Hash == html.A {
					getAttributes(&attrTokenBuffer, tb, html.Id, html.Name, html.Rel, html.Href)
					if id := attrTokenBuffer[0]; id != nil {
						if name := attrTokenBuffer[1]; name != nil && parse.Equal(id.AttrVal, name.AttrVal) {
							name.Data = nil
						}
					}
					if href := attrTokenBuffer[3]; href != nil {
						if len(href.AttrVal) > 5 && parse.EqualFold(href.AttrVal[:4], httpBytes) {
							if href.AttrVal[4] == ':' {
								if m.URL != nil && m.URL.Scheme == "http" {
									href.AttrVal = href.AttrVal[5:]
								} else {
									parse.ToLower(href.AttrVal[:4])
								}
							} else if (href.AttrVal[4] == 's' || href.AttrVal[4] == 'S') && href.AttrVal[5] == ':' {
								if m.URL != nil && m.URL.Scheme == "https" {
									href.AttrVal = href.AttrVal[6:]
								} else {
									parse.ToLower(href.AttrVal[:5])
								}
							}
						}
					}
				} else if t.Hash == html.Meta {
					getAttributes(&attrTokenBuffer, tb, html.Content, html.Http_Equiv, html.Charset, html.Name)
					if content := attrTokenBuffer[0]; content != nil {
						if httpEquiv := attrTokenBuffer[1]; httpEquiv != nil {
							content.AttrVal = minify.ContentType(content.AttrVal)
							if charset := attrTokenBuffer[2]; charset == nil && parse.EqualFold(httpEquiv.AttrVal, []byte("content-type")) && parse.Equal(content.AttrVal, []byte("text/html;charset=utf-8")) {
								httpEquiv.Data = nil
								content.Data = []byte("charset")
								content.Hash = html.Charset
								content.AttrVal = []byte("utf-8")
							} else if parse.EqualFold(httpEquiv.AttrVal, []byte("content-style-type")) {
								defaultStyleType, defaultStyleParams = parse.Mediatype(content.AttrVal)
								if defaultStyleParams != nil {
									defaultInlineStyleParams = defaultStyleParams
									defaultInlineStyleParams["inline"] = "1"
								} else {
									defaultInlineStyleParams = map[string]string{"inline": "1"}
								}
							} else if parse.EqualFold(httpEquiv.AttrVal, []byte("content-script-type")) {
								defaultScriptType, defaultScriptParams = parse.Mediatype(content.AttrVal)
							}
						}
						if name := attrTokenBuffer[3]; name != nil {
							if parse.EqualFold(name.AttrVal, []byte("keywords")) {
								content.AttrVal = bytes.Replace(content.AttrVal, []byte(", "), []byte(","), -1)
							} else if parse.EqualFold(name.AttrVal, []byte("viewport")) {
								content.AttrVal = bytes.Replace(content.AttrVal, []byte(" "), []byte(""), -1)
							}
						}
					}
				} else if t.Hash == html.Script {
					getAttributes(&attrTokenBuffer, tb, html.Src, html.Charset)
					if src := attrTokenBuffer[0]; src != nil {
						if charset := attrTokenBuffer[1]; charset != nil {
							charset.Data = nil
						}
					}
				}

				// write attributes
				for {
					attr := *tb.Shift()
					if attr.TokenType != html.AttributeToken {
						break
					} else if attr.Data == nil {
						continue // removed attribute
					}

					val := attr.AttrVal
					if len(val) > 1 && (val[0] == '"' || val[0] == '\'') {
						val = parse.TrimWhitespace(val[1 : len(val)-1])
					}
					if len(val) == 0 && (attr.Hash == html.Class ||
						attr.Hash == html.Dir ||
						attr.Hash == html.Id ||
						attr.Hash == html.Lang ||
						attr.Hash == html.Name ||
						attr.Hash == html.Title ||
						attr.Hash == html.Action && t.Hash == html.Form ||
						attr.Hash == html.Value && t.Hash == html.Input) {
						continue // omit empty attribute values
					}
					if attr.Traits&caselessAttr != 0 {
						val = parse.ToLower(val)
						if attr.Hash == html.Enctype || attr.Hash == html.Codetype || attr.Hash == html.Accept || attr.Hash == html.Type && (t.Hash == html.A || t.Hash == html.Link || t.Hash == html.Object || t.Hash == html.Param || t.Hash == html.Script || t.Hash == html.Style || t.Hash == html.Source) {
							val = minify.ContentType(val)
						}
					}
					if rawTagHash != 0 && attr.Hash == html.Type {
						rawTagMediatype = val
					}

					// default attribute values can be ommited
					if !o.KeepDefaultAttrVals && (attr.Hash == html.Type && (t.Hash == html.Script && parse.Equal(val, []byte("text/javascript")) ||
						t.Hash == html.Style && parse.Equal(val, []byte("text/css")) ||
						t.Hash == html.Link && parse.Equal(val, []byte("text/css")) ||
						t.Hash == html.Input && parse.Equal(val, []byte("text")) ||
						t.Hash == html.Button && parse.Equal(val, []byte("submit"))) ||
						attr.Hash == html.Language && t.Hash == html.Script ||
						attr.Hash == html.Method && parse.Equal(val, []byte("get")) ||
						attr.Hash == html.Enctype && parse.Equal(val, []byte("application/x-www-form-urlencoded")) ||
						attr.Hash == html.Colspan && parse.Equal(val, []byte("1")) ||
						attr.Hash == html.Rowspan && parse.Equal(val, []byte("1")) ||
						attr.Hash == html.Shape && parse.Equal(val, []byte("rect")) ||
						attr.Hash == html.Span && parse.Equal(val, []byte("1")) ||
						attr.Hash == html.Clear && parse.Equal(val, []byte("none")) ||
						attr.Hash == html.Frameborder && parse.Equal(val, []byte("1")) ||
						attr.Hash == html.Scrolling && parse.Equal(val, []byte("auto")) ||
						attr.Hash == html.Valuetype && parse.Equal(val, []byte("data")) ||
						attr.Hash == html.Media && t.Hash == html.Style && parse.Equal(val, []byte("all"))) {
						continue
					}
					// CSS and JS minifiers for attribute inline code
					if attr.Hash == html.Style {
						attrMinifyBuffer.Reset()
						if m.MinifyMimetype(defaultStyleType, attrMinifyBuffer, buffer.NewReader(val), defaultInlineStyleParams) == nil {
							val = attrMinifyBuffer.Bytes()
						}
						if len(val) == 0 {
							continue
						}
					} else if len(attr.Data) > 2 && attr.Data[0] == 'o' && attr.Data[1] == 'n' {
						if len(val) >= 11 && parse.EqualFold(val[:11], jsSchemeBytes) {
							val = val[11:]
						}
						attrMinifyBuffer.Reset()
						if m.MinifyMimetype(defaultScriptType, attrMinifyBuffer, buffer.NewReader(val), defaultScriptParams) == nil {
							val = attrMinifyBuffer.Bytes()
						}
						if len(val) == 0 {
							continue
						}
					} else if len(val) > 5 && attr.Traits&urlAttr != 0 { // anchors are already handled
						if t.Hash != html.A {
							if parse.EqualFold(val[:4], httpBytes) {
								if val[4] == ':' {
									if m.URL != nil && m.URL.Scheme == "http" {
										val = val[5:]
									} else {
										parse.ToLower(val[:4])
									}
								} else if (val[4] == 's' || val[4] == 'S') && val[5] == ':' {
									if m.URL != nil && m.URL.Scheme == "https" {
										val = val[6:]
									} else {
										parse.ToLower(val[:5])
									}
								}
							}
						}
						if parse.EqualFold(val[:5], dataSchemeBytes) {
							val = minify.DataURI(m, val)
						}
					}

					if _, err := w.Write(spaceBytes); err != nil {
						return err
					}
					if _, err := w.Write(attr.Data); err != nil {
						return err
					}
					if len(val) > 0 && attr.Traits&booleanAttr == 0 {
						if _, err := w.Write(isBytes); err != nil {
							return err
						}
						// no quotes if possible, else prefer single or double depending on which occurs more often in value
						val = html.EscapeAttrVal(&attrByteBuffer, attr.AttrVal, val)
						if _, err := w.Write(val); err != nil {
							return err
						}
					}
				}
			}
			if _, err := w.Write(gtBytes); err != nil {
				return err
			}
		}
	}
}
Exemplo n.º 2
0
// Minify minifies SVG data, it reads from r and writes to w.
func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
	var tag svg.Hash
	defaultStyleType := cssMimeBytes
	defaultStyleParams := map[string]string(nil)
	defaultInlineStyleParams := map[string]string{"inline": "1"}

	p := NewPathData(o)
	minifyBuffer := buffer.NewWriter(make([]byte, 0, 64))
	attrByteBuffer := make([]byte, 0, 64)
	gStack := make([]bool, 0)

	l := xml.NewLexer(r)
	tb := NewTokenBuffer(l)
	for {
		t := *tb.Shift()
	SWITCH:
		switch t.TokenType {
		case xml.ErrorToken:
			if l.Err() == io.EOF {
				return nil
			}
			return l.Err()
		case xml.DOCTYPEToken:
			if len(t.Text) > 0 && t.Text[len(t.Text)-1] == ']' {
				if _, err := w.Write(t.Data); err != nil {
					return err
				}
			}
		case xml.TextToken:
			t.Data = parse.ReplaceMultipleWhitespace(parse.TrimWhitespace(t.Data))
			if tag == svg.Style && len(t.Data) > 0 {
				if err := m.MinifyMimetype(defaultStyleType, w, buffer.NewReader(t.Data), defaultStyleParams); err != nil {
					if err != minify.ErrNotExist {
						return err
					} else if _, err := w.Write(t.Data); err != nil {
						return err
					}
				}
			} else if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.CDATAToken:
			if tag == svg.Style {
				minifyBuffer.Reset()
				if err := m.MinifyMimetype(defaultStyleType, minifyBuffer, buffer.NewReader(t.Text), defaultStyleParams); err == nil {
					t.Data = append(t.Data[:9], minifyBuffer.Bytes()...)
					t.Text = t.Data[9:]
					t.Data = append(t.Data, cdataEndBytes...)
				} else if err != minify.ErrNotExist {
					return err
				}
			}
			var useText bool
			if t.Text, useText = xml.EscapeCDATAVal(&attrByteBuffer, t.Text); useText {
				t.Text = parse.ReplaceMultipleWhitespace(parse.TrimWhitespace(t.Text))
				if _, err := w.Write(t.Text); err != nil {
					return err
				}
			} else if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.StartTagPIToken:
			for {
				if t := *tb.Shift(); t.TokenType == xml.StartTagClosePIToken || t.TokenType == xml.ErrorToken {
					break
				}
			}
		case xml.StartTagToken:
			tag = t.Hash
			if containerTagMap[tag] { // skip empty containers
				i := 0
				for {
					next := tb.Peek(i)
					i++
					if next.TokenType == xml.EndTagToken && next.Hash == tag || next.TokenType == xml.StartTagCloseVoidToken || next.TokenType == xml.ErrorToken {
						for j := 0; j < i; j++ {
							tb.Shift()
						}
						break SWITCH
					} else if next.TokenType != xml.AttributeToken && next.TokenType != xml.StartTagCloseToken {
						break
					}
				}
				if tag == svg.G {
					if tb.Peek(0).TokenType == xml.StartTagCloseToken {
						gStack = append(gStack, false)
						tb.Shift()
						break
					}
					gStack = append(gStack, true)
				}
			} else if tag == svg.Metadata {
				skipTag(tb, tag)
				break
			} else if tag == svg.Line {
				o.shortenLine(tb, &t, p)
			} else if tag == svg.Rect && !o.shortenRect(tb, &t, p) {
				skipTag(tb, tag)
				break
			} else if tag == svg.Polygon || tag == svg.Polyline {
				o.shortenPoly(tb, &t, p)
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.AttributeToken:
			if len(t.AttrVal) == 0 || t.Text == nil { // data is nil when attribute has been removed
				continue
			}

			attr := t.Hash
			val := t.AttrVal
			if n, m := parse.Dimension(val); n+m == len(val) { // TODO: inefficient, temporary measure
				val, _ = o.shortenDimension(val)
			}
			if attr == svg.Xml_Space && parse.Equal(val, []byte("preserve")) ||
				tag == svg.Svg && (attr == svg.Version && parse.Equal(val, []byte("1.1")) ||
					attr == svg.X && parse.Equal(val, []byte("0")) ||
					attr == svg.Y && parse.Equal(val, []byte("0")) ||
					attr == svg.Width && parse.Equal(val, []byte("100%")) ||
					attr == svg.Height && parse.Equal(val, []byte("100%")) ||
					attr == svg.PreserveAspectRatio && parse.Equal(val, []byte("xMidYMid meet")) ||
					attr == svg.BaseProfile && parse.Equal(val, []byte("none")) ||
					attr == svg.ContentScriptType && parse.Equal(val, []byte("application/ecmascript")) ||
					attr == svg.ContentStyleType && parse.Equal(val, []byte("text/css"))) ||
				tag == svg.Style && attr == svg.Type && parse.Equal(val, []byte("text/css")) {
				continue
			}

			if _, err := w.Write(spaceBytes); err != nil {
				return err
			}
			if _, err := w.Write(t.Text); err != nil {
				return err
			}
			if _, err := w.Write(isBytes); err != nil {
				return err
			}

			if tag == svg.Svg && attr == svg.ContentStyleType {
				val = minify.ContentType(val)
				defaultStyleType = val
			} else if attr == svg.Style {
				minifyBuffer.Reset()
				if err := m.MinifyMimetype(defaultStyleType, minifyBuffer, buffer.NewReader(val), defaultInlineStyleParams); err == nil {
					val = minifyBuffer.Bytes()
				} else if err != minify.ErrNotExist {
					return err
				}
			} else if attr == svg.D {
				val = p.ShortenPathData(val)
			} else if attr == svg.ViewBox {
				j := 0
				newVal := val[:0]
				for i := 0; i < 4; i++ {
					if i != 0 {
						if j >= len(val) || val[j] != ' ' && val[j] != ',' {
							newVal = append(newVal, val[j:]...)
							break
						}
						newVal = append(newVal, ' ')
						j++
					}
					if dim, n := o.shortenDimension(val[j:]); n > 0 {
						newVal = append(newVal, dim...)
						j += n
					} else {
						newVal = append(newVal, val[j:]...)
						break
					}
				}
				val = newVal
			} else if colorAttrMap[attr] && len(val) > 0 {
				parse.ToLower(val)
				if val[0] == '#' {
					if name, ok := minifyCSS.ShortenColorHex[string(val)]; ok {
						val = name
					} else if len(val) == 7 && val[1] == val[2] && val[3] == val[4] && val[5] == val[6] {
						val[2] = val[3]
						val[3] = val[5]
						val = val[:4]
					}
				} else if hex, ok := minifyCSS.ShortenColorName[css.ToHash(val)]; ok {
					val = hex
				} else if len(val) > 5 && parse.Equal(val[:4], []byte("rgb(")) && val[len(val)-1] == ')' {
					// TODO: handle rgb(x, y, z) and hsl(x, y, z)
				}
			}

			// prefer single or double quotes depending on what occurs more often in value
			val = xml.EscapeAttrVal(&attrByteBuffer, val)
			if _, err := w.Write(val); err != nil {
				return err
			}
		case xml.StartTagCloseToken:
			next := tb.Peek(0)
			skipExtra := false
			if next.TokenType == xml.TextToken && parse.IsAllWhitespace(next.Data) {
				next = tb.Peek(1)
				skipExtra = true
			}
			if next.TokenType == xml.EndTagToken {
				// collapse empty tags to single void tag
				tb.Shift()
				if skipExtra {
					tb.Shift()
				}
				if _, err := w.Write(voidBytes); err != nil {
					return err
				}
			} else {
				if _, err := w.Write(t.Data); err != nil {
					return err
				}
			}
		case xml.StartTagCloseVoidToken:
			tag = 0
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.EndTagToken:
			tag = 0
			if t.Hash == svg.G && len(gStack) > 0 {
				if !gStack[len(gStack)-1] {
					gStack = gStack[:len(gStack)-1]
					break
				}
				gStack = gStack[:len(gStack)-1]
			}
			if len(t.Data) > 3+len(t.Text) {
				t.Data[2+len(t.Text)] = '>'
				t.Data = t.Data[:3+len(t.Text)]
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
		}
	}
}
Exemplo n.º 3
0
Arquivo: svg.go Projeto: chnfow/minify
// Minify minifies SVG data, it reads from r and writes to w.
func (o *Minifier) Minify(m *minify.M, w io.Writer, r io.Reader, _ map[string]string) error {
	var tag svg.Hash
	defaultStyleType := "text/css"
	defaultInlineStyleType := "text/css;inline=1"

	attrMinifyBuffer := buffer.NewWriter(make([]byte, 0, 64))
	attrByteBuffer := make([]byte, 0, 64)

	l := xml.NewLexer(r)
	tb := NewTokenBuffer(l)
	for {
		t := *tb.Shift()
		if t.TokenType == xml.CDATAToken {
			var useText bool
			if t.Data, useText = xml.EscapeCDATAVal(&attrByteBuffer, t.Data); useText {
				t.TokenType = xml.TextToken
			}
		}
	SWITCH:
		switch t.TokenType {
		case xml.ErrorToken:
			if l.Err() == io.EOF {
				return nil
			}
			return l.Err()
		case xml.TextToken:
			t.Data = parse.ReplaceMultipleWhitespace(parse.TrimWhitespace(t.Data))
			if tag == svg.Style && len(t.Data) > 0 {
				if err := m.Minify(defaultStyleType, w, buffer.NewReader(t.Data)); err != nil {
					if err == minify.ErrNotExist { // no minifier, write the original
						if _, err := w.Write(t.Data); err != nil {
							return err
						}
					} else {
						return err
					}
				}
			} else if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.CDATAToken:
			if _, err := w.Write(cdataStartBytes); err != nil {
				return err
			}
			t.Data = parse.ReplaceMultipleWhitespace(parse.TrimWhitespace(t.Data))
			if tag == svg.Style && len(t.Data) > 0 {
				if err := m.Minify(defaultStyleType, w, buffer.NewReader(t.Data)); err != nil {
					if err == minify.ErrNotExist { // no minifier, write the original
						if _, err := w.Write(t.Data); err != nil {
							return err
						}
					} else {
						return err
					}
				}
			} else if _, err := w.Write(t.Data); err != nil {
				return err
			}
			if _, err := w.Write(cdataEndBytes); err != nil {
				return err
			}
		case xml.StartTagPIToken:
			for {
				if t := *tb.Shift(); t.TokenType == xml.StartTagClosePIToken || t.TokenType == xml.ErrorToken {
					break
				}
			}
		case xml.StartTagToken:
			tag = t.Hash
			if containerTagMap[t.Hash] { // skip empty containers
				i := 0
				for {
					next := tb.Peek(i)
					i++
					if next.TokenType == xml.EndTagToken && next.Hash == t.Hash || next.TokenType == xml.StartTagCloseVoidToken || next.TokenType == xml.ErrorToken {
						for j := 0; j < i; j++ {
							tb.Shift()
						}
						break SWITCH
					} else if next.TokenType != xml.AttributeToken && next.TokenType != xml.StartTagCloseToken {
						break
					}
				}
			} else if t.Hash == svg.Metadata {
				for {
					if next := *tb.Shift(); (next.TokenType == xml.EndTagToken || next.TokenType == xml.StartTagCloseVoidToken) && next.Hash == t.Hash || next.TokenType == xml.ErrorToken {
						break
					}
				}
				break
			} else if t.Hash == svg.Line || t.Hash == svg.Rect {
				// TODO: shape2path also for polygon and polyline
				// x1, y1, x2, y2 float64 := 0, 0, 0, 0
				// valid := true
				// i := 0
				// for {
				// 	next := tb.Peek(i)
				// 	i++
				// 	if next.TokenType != xml.AttributeToken {
				// 		break
				// 	}
				// 	v *int
				// 	attr := svg.ToHash(next.Data)
				// 	if tag == svg.Line {
				// 		if attr == svg.X1 {
				// 			v = &x1
				// 		} else if attr == svg.Y1 {
				// 			v = &y1
				// 		} else if attr == svg.X2 {
				// 			v = &x2
				// 		} else if attr == svg.Y2 {
				// 			v = &Y2
				// 		} else {
				// 			continue
				// 		}
				// 	} else if attr == svg.X { // rect
				// 		v = &x1
				// 	} else if attr == svg.Y {
				// 		v = &y1
				// 	} else if attr == svg.Width {
				// 		v = &x2
				// 	} else if attr == svg.Height {
				// 		v = &Y2
				// 	} else if attr == svg.Rx || attr == svg.Ry {
				// 		valid = false
				// 		break
				// 	} else {
				// 		continue
				// 	}

				// }
				// if valid {
				// 	t.Data = pathBytes
				// }
			}
			if _, err := w.Write(ltBytes); err != nil {
				return err
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
		case xml.AttributeToken:
			if len(t.AttrVal) < 2 {
				continue
			}
			val := parse.ReplaceMultipleWhitespace(parse.TrimWhitespace(t.AttrVal[1 : len(t.AttrVal)-1]))
			if tag == svg.Svg && t.Hash == svg.Version {
				continue
			}

			if _, err := w.Write(spaceBytes); err != nil {
				return err
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
			if _, err := w.Write(isBytes); err != nil {
				return err
			}

			if tag == svg.Svg && t.Hash == svg.ContentStyleType {
				val = minify.ContentType(val)
				defaultStyleType = string(val)
				defaultInlineStyleType = defaultStyleType + ";inline=1"
			} else if t.Hash == svg.Style {
				attrMinifyBuffer.Reset()
				if m.Minify(defaultInlineStyleType, attrMinifyBuffer, buffer.NewReader(val)) == nil {
					val = attrMinifyBuffer.Bytes()
				}
			} else if t.Hash == svg.D {
				val = shortenPathData(val)
			} else if t.Hash == svg.ViewBox {
				j := 0
				newVal := val[:0]
				for i := 0; i < 4; i++ {
					if i != 0 {
						if j >= len(val) || val[j] != ' ' && val[j] != ',' {
							newVal = append(newVal, val[j:]...)
							break
						}
						newVal = append(newVal, ' ')
						j++
					}
					if dim, n := shortenDimension(val[j:]); n > 0 {
						newVal = append(newVal, dim...)
						j += n
					} else {
						newVal = append(newVal, val[j:]...)
						break
					}
				}
				val = newVal
			} else if colorAttrMap[t.Hash] && len(val) > 0 {
				parse.ToLower(val)
				if val[0] == '#' {
					if name, ok := minifyCSS.ShortenColorHex[string(val)]; ok {
						val = name
					} else if len(val) == 7 && val[1] == val[2] && val[3] == val[4] && val[5] == val[6] {
						val[2] = val[3]
						val[3] = val[5]
						val = val[:4]
					}
				} else if hex, ok := minifyCSS.ShortenColorName[css.ToHash(val)]; ok {
					val = hex
				} else if len(val) > 5 && parse.Equal(val[:4], []byte("rgb(")) && val[len(val)-1] == ')' {
					// TODO: handle rgb(x, y, z) and hsl(x, y, z)
				}
			} else if n, m := parse.Dimension(val); n+m == len(val) { // TODO: inefficient, temporary measure
				val, _ = shortenDimension(val)
			}

			// prefer single or double quotes depending on what occurs more often in value
			val = xml.EscapeAttrVal(&attrByteBuffer, val)
			if _, err := w.Write(val); err != nil {
				return err
			}
		case xml.StartTagCloseToken:
			next := tb.Peek(0)
			skipExtra := false
			if next.TokenType == xml.TextToken && parse.IsAllWhitespace(next.Data) {
				next = tb.Peek(1)
				skipExtra = true
			}
			if next.TokenType == xml.EndTagToken {
				// collapse empty tags to single void tag
				tb.Shift()
				if skipExtra {
					tb.Shift()
				}
				if _, err := w.Write(voidBytes); err != nil {
					return err
				}
			} else {
				if _, err := w.Write(gtBytes); err != nil {
					return err
				}
			}
		case xml.StartTagCloseVoidToken:
			if _, err := w.Write(voidBytes); err != nil {
				return err
			}
		case xml.EndTagToken:
			if _, err := w.Write(endBytes); err != nil {
				return err
			}
			if _, err := w.Write(t.Data); err != nil {
				return err
			}
			if _, err := w.Write(gtBytes); err != nil {
				return err
			}
		}
	}
}