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Simplify PrivateRR copying (#960) 

This eliminates mkPrivateRR and reduces the risk of panic.
This commit is contained in:
Tom Thorogood 2019-04-30 17:44:59 +09:30 committed by Miek Gieben
parent 56c04f1fec
commit 92185d1e17
1 changed files with 8 additions and 26 deletions
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34
privaterr.go
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@ -1,9 +1,6 @@
package dns
import (
"fmt"
"strings"
)
import "strings"
// PrivateRdata is an interface used for implementing "Private Use" RR types, see
// RFC 6895. This allows one to experiment with new RR types, without requesting an
@ -18,7 +15,7 @@ type PrivateRdata interface {
// Unpack is used when unpacking a private RR from a buffer.
// TODO(miek): diff. signature than Pack, see edns0.go for instance.
Unpack([]byte) (int, error)
// Copy copies the Rdata.
// Copy copies the Rdata into the PrivateRdata argument.
Copy(PrivateRdata) error
// Len returns the length in octets of the Rdata.
Len() int
@ -29,22 +26,8 @@ type PrivateRdata interface {
type PrivateRR struct {
Hdr RR_Header
Data PrivateRdata
}
func mkPrivateRR(rrtype uint16) *PrivateRR {
// Panics if RR is not an instance of PrivateRR.
rrfunc, ok := TypeToRR[rrtype]
if !ok {
panic(fmt.Sprintf("dns: invalid operation with Private RR type %d", rrtype))
}
anyrr := rrfunc()
rr, ok := anyrr.(*PrivateRR)
if !ok {
panic(fmt.Sprintf("dns: RR is not a PrivateRR, TypeToRR[%d] generator returned %T", rrtype, anyrr))
}
return rr
generator func() PrivateRdata // for copy
}
// Header return the RR header of r.
@ -61,13 +44,12 @@ func (r *PrivateRR) len(off int, compression map[string]struct{}) int {
func (r *PrivateRR) copy() RR {
// make new RR like this:
rr := mkPrivateRR(r.Hdr.Rrtype)
rr.Hdr = r.Hdr
rr := &PrivateRR{r.Hdr, r.generator(), r.generator}
err := r.Data.Copy(rr.Data)
if err != nil {
panic("dns: got value that could not be used to copy Private rdata")
if err := r.Data.Copy(rr.Data); err != nil {
panic("dns: got value that could not be used to copy Private rdata: " + err.Error())
}
return rr
}
@ -116,7 +98,7 @@ func (r1 *PrivateRR) isDuplicate(r2 RR) bool { return false }
func PrivateHandle(rtypestr string, rtype uint16, generator func() PrivateRdata) {
rtypestr = strings.ToUpper(rtypestr)
TypeToRR[rtype] = func() RR { return &PrivateRR{RR_Header{}, generator()} }
TypeToRR[rtype] = func() RR { return &PrivateRR{RR_Header{}, generator(), generator} }
TypeToString[rtype] = rtypestr
StringToType[rtypestr] = rtype
}