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