Add msgpack wire protocol with halfsiphash checksums

lib/tagparser/tagparser.go

@@ -0,0 +1,162 @@
+package tagparser
+
+import "strings"
+
+type Tag struct {
+	Name    string
+	Options map[string]string
+}
+
+func (t *Tag) HasOption(name string) bool {
+	_, ok := t.Options[name]
+	return ok
+}
+
+func Parse(s string) *Tag {
+	p := &tagParser{
+		Parser: newStringParser(s),
+	}
+	p.parseKey()
+	return &p.Tag
+}
+
+type tagParser struct {
+	*Parser
+
+	Tag     Tag
+	hasName bool
+	key     string
+}
+
+func (p *tagParser) setTagOption(key, value string) {
+	key = strings.TrimSpace(key)
+	value = strings.TrimSpace(value)
+
+	if !p.hasName {
+		p.hasName = true
+		if key == "" {
+			p.Tag.Name = value
+			return
+		}
+	}
+	if p.Tag.Options == nil {
+		p.Tag.Options = make(map[string]string)
+	}
+	if key == "" {
+		p.Tag.Options[value] = ""
+	} else {
+		p.Tag.Options[key] = value
+	}
+}
+
+func (p *tagParser) parseKey() {
+	p.key = ""
+
+	var b []byte
+	for p.Valid() {
+		c := p.Read()
+		switch c {
+		case ',':
+			p.Skip(' ')
+			p.setTagOption("", string(b))
+			p.parseKey()
+			return
+		case ':':
+			p.key = string(b)
+			p.parseValue()
+			return
+		case '\'':
+			p.parseQuotedValue()
+			return
+		default:
+			b = append(b, c)
+		}
+	}
+
+	if len(b) > 0 {
+		p.setTagOption("", string(b))
+	}
+}
+
+func (p *tagParser) parseValue() {
+	const quote = '\''
+	c := p.Peek()
+	if c == quote {
+		p.Skip(quote)
+		p.parseQuotedValue()
+		return
+	}
+
+	var b []byte
+	for p.Valid() {
+		c = p.Read()
+		switch c {
+		case '\\':
+			b = append(b, p.Read())
+		case '(':
+			b = append(b, c)
+			b = p.readBrackets(b)
+		case ',':
+			p.Skip(' ')
+			p.setTagOption(p.key, string(b))
+			p.parseKey()
+			return
+		default:
+			b = append(b, c)
+		}
+	}
+	p.setTagOption(p.key, string(b))
+}
+
+func (p *tagParser) readBrackets(b []byte) []byte {
+	var lvl int
+loop:
+	for p.Valid() {
+		c := p.Read()
+		switch c {
+		case '\\':
+			b = append(b, p.Read())
+		case '(':
+			b = append(b, c)
+			lvl++
+		case ')':
+			b = append(b, c)
+			lvl--
+			if lvl < 0 {
+				break loop
+			}
+		default:
+			b = append(b, c)
+		}
+	}
+	return b
+}
+
+func (p *tagParser) parseQuotedValue() {
+	const quote = '\''
+	var b []byte
+	for p.Valid() {
+		bb, ok := p.ReadSep(quote)
+		if !ok {
+			b = append(b, bb...)
+			break
+		}
+
+		// keep the escaped single-quote, and continue until we've found the
+		// one that isn't.
+		if len(bb) > 0 && bb[len(bb)-1] == '\\' {
+			b = append(b, bb[:len(bb)-1]...)
+			b = append(b, quote)
+			continue
+		}
+
+		b = append(b, bb...)
+		break
+	}
+
+	p.setTagOption(p.key, string(b))
+	if p.Skip(',') {
+		p.Skip(' ')
+	}
+	p.parseKey()
+}