in proto/properties.go [137:191]
func (p *Properties) Parse(tag string) {
// For example: "bytes,49,opt,name=foo,def=hello!"
for len(tag) > 0 {
i := strings.IndexByte(tag, ',')
if i < 0 {
i = len(tag)
}
switch s := tag[:i]; {
case strings.HasPrefix(s, "name="):
p.OrigName = s[len("name="):]
case strings.HasPrefix(s, "json="):
p.JSONName = s[len("json="):]
case strings.HasPrefix(s, "enum="):
p.Enum = s[len("enum="):]
case strings.HasPrefix(s, "weak="):
p.Weak = s[len("weak="):]
case strings.Trim(s, "0123456789") == "":
n, _ := strconv.ParseUint(s, 10, 32)
p.Tag = int(n)
case s == "opt":
p.Optional = true
case s == "req":
p.Required = true
case s == "rep":
p.Repeated = true
case s == "varint" || s == "zigzag32" || s == "zigzag64":
p.Wire = s
p.WireType = WireVarint
case s == "fixed32":
p.Wire = s
p.WireType = WireFixed32
case s == "fixed64":
p.Wire = s
p.WireType = WireFixed64
case s == "bytes":
p.Wire = s
p.WireType = WireBytes
case s == "group":
p.Wire = s
p.WireType = WireStartGroup
case s == "packed":
p.Packed = true
case s == "proto3":
p.Proto3 = true
case s == "oneof":
p.Oneof = true
case strings.HasPrefix(s, "def="):
// The default tag is special in that everything afterwards is the
// default regardless of the presence of commas.
p.HasDefault = true
p.Default, i = tag[len("def="):], len(tag)
}
tag = strings.TrimPrefix(tag[i:], ",")
}
}