well-goknown/vendor/github.com/gobwas/httphead/writer.go

102 lines
2.2 KiB
Go

package httphead
import "io"
var (
comma = []byte{','}
equality = []byte{'='}
semicolon = []byte{';'}
quote = []byte{'"'}
escape = []byte{'\\'}
)
// WriteOptions write options list to the dest.
// It uses the same form as {Scan,Parse}Options functions:
// values = 1#value
// value = token *( ";" param )
// param = token [ "=" (token | quoted-string) ]
//
// It wraps valuse into the quoted-string sequence if it contains any
// non-token characters.
func WriteOptions(dest io.Writer, options []Option) (n int, err error) {
w := writer{w: dest}
for i, opt := range options {
if i > 0 {
w.write(comma)
}
writeTokenSanitized(&w, opt.Name)
for _, p := range opt.Parameters.data() {
w.write(semicolon)
writeTokenSanitized(&w, p.key)
if len(p.value) != 0 {
w.write(equality)
writeTokenSanitized(&w, p.value)
}
}
}
return w.result()
}
// writeTokenSanitized writes token as is or as quouted string if it contains
// non-token characters.
//
// Note that is is not expects LWS sequnces be in s, cause LWS is used only as
// header field continuation:
// "A CRLF is allowed in the definition of TEXT only as part of a header field
// continuation. It is expected that the folding LWS will be replaced with a
// single SP before interpretation of the TEXT value."
// See https://tools.ietf.org/html/rfc2616#section-2
//
// That is we sanitizing s for writing, so there could not be any header field
// continuation.
// That is any CRLF will be escaped as any other control characters not allowd in TEXT.
func writeTokenSanitized(bw *writer, bts []byte) {
var qt bool
var pos int
for i := 0; i < len(bts); i++ {
c := bts[i]
if !OctetTypes[c].IsToken() && !qt {
qt = true
bw.write(quote)
}
if OctetTypes[c].IsControl() || c == '"' {
if !qt {
qt = true
bw.write(quote)
}
bw.write(bts[pos:i])
bw.write(escape)
bw.write(bts[i : i+1])
pos = i + 1
}
}
if !qt {
bw.write(bts)
} else {
bw.write(bts[pos:])
bw.write(quote)
}
}
type writer struct {
w io.Writer
n int
err error
}
func (w *writer) write(p []byte) {
if w.err != nil {
return
}
var n int
n, w.err = w.w.Write(p)
w.n += n
return
}
func (w *writer) result() (int, error) {
return w.n, w.err
}