135 lines
3.1 KiB
Go
135 lines
3.1 KiB
Go
package multiaddr
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import (
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"bytes"
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"fmt"
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"strings"
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)
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// multiaddr is the data structure representing a Multiaddr
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type multiaddr struct {
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bytes []byte
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}
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// NewMultiaddr parses and validates an input string, returning a *Multiaddr
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func NewMultiaddr(s string) (Multiaddr, error) {
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b, err := stringToBytes(s)
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if err != nil {
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return nil, err
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}
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return &multiaddr{bytes: b}, nil
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}
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// NewMultiaddrBytes initializes a Multiaddr from a byte representation.
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// It validates it as an input string.
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func NewMultiaddrBytes(b []byte) (Multiaddr, error) {
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if err := validateBytes(b); err != nil {
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return nil, err
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}
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return &multiaddr{bytes: b}, nil
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}
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// Equal tests whether two multiaddrs are equal
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func (m *multiaddr) Equal(m2 Multiaddr) bool {
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return bytes.Equal(m.bytes, m2.Bytes())
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}
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// Bytes returns the []byte representation of this Multiaddr
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func (m *multiaddr) Bytes() []byte {
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// consider returning copy to prevent changing underneath us?
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cpy := make([]byte, len(m.bytes))
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copy(cpy, m.bytes)
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return cpy
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}
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// String returns the string representation of a Multiaddr
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func (m *multiaddr) String() string {
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s, err := bytesToString(m.bytes)
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if err != nil {
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panic("multiaddr failed to convert back to string. corrupted?")
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}
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return s
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}
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// Protocols returns the list of protocols this Multiaddr has.
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// will panic in case we access bytes incorrectly.
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func (m *multiaddr) Protocols() []Protocol {
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// panic handler, in case we try accessing bytes incorrectly.
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defer func() {
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if e := recover(); e != nil {
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err := e.(error)
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panic("Multiaddr.Protocols error: " + err.Error())
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}
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}()
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var ps []Protocol
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b := m.bytes
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for len(b) > 0 {
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code, n, err := ReadVarintCode(b)
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if err != nil {
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panic(err)
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}
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p := ProtocolWithCode(code)
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if p.Code == 0 {
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// this is a panic (and not returning err) because this should've been
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// caught on constructing the Multiaddr
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panic(fmt.Errorf("no protocol with code %d", b[0]))
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}
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ps = append(ps, p)
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b = b[n:]
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size, err := sizeForAddr(p, b)
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b = b[size:]
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}
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return ps
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}
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// Encapsulate wraps a given Multiaddr, returning the resulting joined Multiaddr
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func (m *multiaddr) Encapsulate(o Multiaddr) Multiaddr {
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mb := m.bytes
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ob := o.Bytes()
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b := make([]byte, len(mb)+len(ob))
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copy(b, mb)
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copy(b[len(mb):], ob)
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return &multiaddr{bytes: b}
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}
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// Decapsulate unwraps Multiaddr up until the given Multiaddr is found.
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func (m *multiaddr) Decapsulate(o Multiaddr) Multiaddr {
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s1 := m.String()
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s2 := o.String()
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i := strings.LastIndex(s1, s2)
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if i < 0 {
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// if multiaddr not contained, returns a copy.
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cpy := make([]byte, len(m.bytes))
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copy(cpy, m.bytes)
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return &multiaddr{bytes: cpy}
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}
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ma, err := NewMultiaddr(s1[:i])
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if err != nil {
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panic("Multiaddr.Decapsulate incorrect byte boundaries.")
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}
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return ma
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}
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var ErrProtocolNotFound = fmt.Errorf("protocol not found in multiaddr")
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func (m *multiaddr) ValueForProtocol(code int) (string, error) {
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for _, sub := range Split(m) {
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p := sub.Protocols()[0]
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if p.Code == code {
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if p.Size == 0 {
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return "", nil
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}
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return strings.Split(sub.String(), "/")[2], nil
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}
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}
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return "", ErrProtocolNotFound
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}
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