First commit

vendor/github.com/tdewolff/minify/html/buffer.go

@@ -0,0 +1,131 @@
+package html // import "github.com/tdewolff/minify/html"
+
+import (
+	"github.com/tdewolff/parse"
+	"github.com/tdewolff/parse/html"
+)
+
+// Token is a single token unit with an attribute value (if given) and hash of the data.
+type Token struct {
+	html.TokenType
+	Hash    html.Hash
+	Data    []byte
+	Text    []byte
+	AttrVal []byte
+	Traits  traits
+}
+
+// TokenBuffer is a buffer that allows for token look-ahead.
+type TokenBuffer struct {
+	l *html.Lexer
+
+	buf []Token
+	pos int
+
+	attrBuffer []*Token
+}
+
+// NewTokenBuffer returns a new TokenBuffer.
+func NewTokenBuffer(l *html.Lexer) *TokenBuffer {
+	return &TokenBuffer{
+		l:   l,
+		buf: make([]Token, 0, 8),
+	}
+}
+
+func (z *TokenBuffer) read(t *Token) {
+	t.TokenType, t.Data = z.l.Next()
+	t.Text = z.l.Text()
+	if t.TokenType == html.AttributeToken {
+		t.AttrVal = z.l.AttrVal()
+		if len(t.AttrVal) > 1 && (t.AttrVal[0] == '"' || t.AttrVal[0] == '\'') {
+			t.AttrVal = parse.TrimWhitespace(t.AttrVal[1 : len(t.AttrVal)-1]) // quotes will be readded in attribute loop if necessary
+		}
+		t.Hash = html.ToHash(t.Text)
+		t.Traits = attrMap[t.Hash]
+	} else if t.TokenType == html.StartTagToken || t.TokenType == html.EndTagToken {
+		t.AttrVal = nil
+		t.Hash = html.ToHash(t.Text)
+		t.Traits = tagMap[t.Hash]
+	} else {
+		t.AttrVal = nil
+		t.Hash = 0
+		t.Traits = 0
+	}
+}
+
+// Peek returns the ith element and possibly does an allocation.
+// Peeking past an error will panic.
+func (z *TokenBuffer) Peek(pos int) *Token {
+	pos += z.pos
+	if pos >= len(z.buf) {
+		if len(z.buf) > 0 && z.buf[len(z.buf)-1].TokenType == html.ErrorToken {
+			return &z.buf[len(z.buf)-1]
+		}
+
+		c := cap(z.buf)
+		d := len(z.buf) - z.pos
+		p := pos - z.pos + 1 // required peek length
+		var buf []Token
+		if 2*p > c {
+			buf = make([]Token, 0, 2*c+p)
+		} else {
+			buf = z.buf
+		}
+		copy(buf[:d], z.buf[z.pos:])
+
+		buf = buf[:p]
+		pos -= z.pos
+		for i := d; i < p; i++ {
+			z.read(&buf[i])
+			if buf[i].TokenType == html.ErrorToken {
+				buf = buf[:i+1]
+				pos = i
+				break
+			}
+		}
+		z.pos, z.buf = 0, buf
+	}
+	return &z.buf[pos]
+}
+
+// Shift returns the first element and advances position.
+func (z *TokenBuffer) Shift() *Token {
+	if z.pos >= len(z.buf) {
+		t := &z.buf[:1][0]
+		z.read(t)
+		return t
+	}
+	t := &z.buf[z.pos]
+	z.pos++
+	return t
+}
+
+// Attributes extracts the gives attribute hashes from a tag.
+// It returns in the same order pointers to the requested token data or nil.
+func (z *TokenBuffer) Attributes(hashes ...html.Hash) []*Token {
+	n := 0
+	for {
+		if t := z.Peek(n); t.TokenType != html.AttributeToken {
+			break
+		}
+		n++
+	}
+	if len(hashes) > cap(z.attrBuffer) {
+		z.attrBuffer = make([]*Token, len(hashes))
+	} else {
+		z.attrBuffer = z.attrBuffer[:len(hashes)]
+		for i := range z.attrBuffer {
+			z.attrBuffer[i] = nil
+		}
+	}
+	for i := z.pos; i < z.pos+n; i++ {
+		attr := &z.buf[i]
+		for j, hash := range hashes {
+			if hash == attr.Hash {
+				z.attrBuffer[j] = attr
+			}
+		}
+	}
+	return z.attrBuffer
+}