ceremonyclient/go-multiaddr/protocol.go
2024-10-12 11:55:17 -07:00

103 lines
2.7 KiB
Go

package multiaddr
import (
"fmt"
"strings"
)
// These are special sizes
const (
LengthPrefixedVarSize = -1
)
// Protocol is a Multiaddr protocol description structure.
type Protocol struct {
// Name is the string representation of the protocol code. E.g., ip4,
// ip6, tcp, udp, etc.
Name string
// Code is the protocol's multicodec (a normal, non-varint number).
Code int
// VCode is a precomputed varint encoded version of Code.
VCode []byte
// Size is the size of the argument to this protocol.
//
// * Size == 0 means this protocol takes no argument.
// * Size > 0 means this protocol takes a constant sized argument.
// * Size < 0 means this protocol takes a variable length, varint
// prefixed argument.
Size int // a size of -1 indicates a length-prefixed variable size
// Path indicates a path protocol (e.g., unix). When parsing multiaddr
// strings, path protocols consume the remainder of the address instead
// of stopping at the next forward slash.
//
// Size must be LengthPrefixedVarSize.
Path bool
// Transcoder converts between the byte representation and the string
// representation of this protocol's argument (if any).
//
// This should only be non-nil if Size != 0
Transcoder Transcoder
}
var protocolsByName = map[string]Protocol{}
var protocolsByCode = map[int]Protocol{}
// Protocols is the list of multiaddr protocols supported by this module.
var Protocols = []Protocol{}
func AddProtocol(p Protocol) error {
if _, ok := protocolsByName[p.Name]; ok {
return fmt.Errorf("protocol by the name %q already exists", p.Name)
}
if _, ok := protocolsByCode[p.Code]; ok {
return fmt.Errorf("protocol code %d already taken by %q", p.Code, p.Code)
}
if p.Size != 0 && p.Transcoder == nil {
return fmt.Errorf("protocols with arguments must define transcoders")
}
if p.Path && p.Size >= 0 {
return fmt.Errorf("path protocols must have variable-length sizes")
}
Protocols = append(Protocols, p)
protocolsByName[p.Name] = p
protocolsByCode[p.Code] = p
return nil
}
// ProtocolWithName returns the Protocol description with given string name.
func ProtocolWithName(s string) Protocol {
return protocolsByName[s]
}
// ProtocolWithCode returns the Protocol description with given protocol code.
func ProtocolWithCode(c int) Protocol {
return protocolsByCode[c]
}
// ProtocolsWithString returns a slice of protocols matching given string.
func ProtocolsWithString(s string) ([]Protocol, error) {
s = strings.Trim(s, "/")
sp := strings.Split(s, "/")
if len(sp) == 0 {
return nil, nil
}
t := make([]Protocol, len(sp))
for i, name := range sp {
p := ProtocolWithName(name)
if p.Code == 0 {
return nil, fmt.Errorf("no protocol with name: %s", name)
}
t[i] = p
}
return t, nil
}