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Extract most of cid-fmt logic so it can be used as a library.
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@kevina
kevina committed Aug 1, 2018
1 parent 36bab48 commit c4bfcd0
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Showing 5 changed files with 246 additions and 242 deletions.
173 changes: 4 additions & 169 deletions cid-fmt/main.go
View file
Original file line number Diff line number Diff line change
@@ -1,46 +1,21 @@
package main

import (
"bytes"
"fmt"
"os"
"strings"

c "github.com/ipfs/go-cid"

mb "github.com/multiformats/go-multibase"
mh "github.com/multiformats/go-multihash"
)

func usage() {
fmt.Fprintf(os.Stderr, "usage: %s [-b multibase-code] [-v cid-version] <fmt-str> <cid> ...\n\n", os.Args[0])
fmt.Fprintf(os.Stderr, "<fmt-str> is either 'prefix' or a printf style format string:\n%s", fmtRef)
fmt.Fprintf(os.Stderr, "<fmt-str> is either 'prefix' or a printf style format string:\n%s", c.FormatRef)
os.Exit(2)
}

const fmtRef = `
%% literal %
%b multibase name
%B multibase code
%v version string
%V version number
%c codec name
%C codec code
%h multihash name
%H multihash code
%L hash digest length
%m multihash encoded in base %b (with multibase prefix)
%M multihash encoded in base %b without multibase prefix
%d hash digest encoded in base %b (with multibase prefix)
%D hash digest encoded in base %b without multibase prefix
%s cid string encoded in base %b (1)
%S cid string encoded in base %b without multibase prefix
%P cid prefix: %v-%c-%h-%L
(1) For CID version 0 the multibase must be base58btc and no prefix is
used. For Cid version 1 the multibase prefix is included.
`

func main() {
if len(os.Args) < 2 {
usage()
Expand Down Expand Up @@ -94,7 +69,7 @@ outer:
}
}
for _, cidStr := range args[1:] {
base, cid, err := decode(cidStr)
base, cid, err := c.DecodeV2(cidStr)
if err != nil {
fmt.Fprintf(os.Stdout, "!INVALID_CID!\n")
errorMsg("%s: %v", cidStr, err)
Expand All @@ -113,9 +88,9 @@ outer:
continue
}
}
str, err := fmtCid(fmtStr, base, cid)
str, err := c.Format(fmtStr, base, cid)
switch err.(type) {
case FormatStringError:
case c.FormatStringError:
fmt.Fprintf(os.Stderr, "Error: %v\n", err)
os.Exit(2)
default:
Expand All @@ -140,146 +115,6 @@ func errorMsg(fmtStr string, a ...interface{}) {
exitCode = 1
}

func decode(v string) (mb.Encoding, *c.Cid, error) {
if len(v) < 2 {
return 0, nil, c.ErrCidTooShort
}

if len(v) == 46 && v[:2] == "Qm" {
hash, err := mh.FromB58String(v)
if err != nil {
return 0, nil, err
}

return mb.Base58BTC, c.NewCidV0(hash), nil
}

base, data, err := mb.Decode(v)
if err != nil {
return 0, nil, err
}

cid, err := c.Cast(data)

return base, cid, err
}

const ERR_STR = "!ERROR!"

type FormatStringError struct {
Message string
Specifier string
}

func (e FormatStringError) Error() string {
if e.Specifier == "" {
return e.Message
} else {
return fmt.Sprintf("%s: %s", e.Message, e.Specifier)
}
}

func fmtCid(fmtStr string, base mb.Encoding, cid *c.Cid) (string, error) {
p := cid.Prefix()
out := new(bytes.Buffer)
var err error
encoder, err := mb.NewEncoder(base)
if err != nil {
return "", err
}
for i := 0; i < len(fmtStr); i++ {
if fmtStr[i] != '%' {
out.WriteByte(fmtStr[i])
continue
}
i++
if i >= len(fmtStr) {
return "", FormatStringError{"premature end of format string", ""}
}
switch fmtStr[i] {
case '%':
out.WriteByte('%')
case 'b': // base name
out.WriteString(baseToString(base))
case 'B': // base code
out.WriteByte(byte(base))
case 'v': // version string
fmt.Fprintf(out, "cidv%d", p.Version)
case 'V': // version num
fmt.Fprintf(out, "%d", p.Version)
case 'c': // codec name
out.WriteString(codecToString(p.Codec))
case 'C': // codec code
fmt.Fprintf(out, "%d", p.Codec)
case 'h': // hash fun name
out.WriteString(hashToString(p.MhType))
case 'H': // hash fun code
fmt.Fprintf(out, "%d", p.MhType)
case 'L': // hash length
fmt.Fprintf(out, "%d", p.MhLength)
case 'm', 'M': // multihash encoded in base %b
out.WriteString(encode(encoder, cid.Hash(), fmtStr[i] == 'M'))
case 'd', 'D': // hash digest encoded in base %b
dec, err := mh.Decode(cid.Hash())
if err != nil {
return "", err
}
out.WriteString(encode(encoder, dec.Digest, fmtStr[i] == 'D'))
case 's': // cid string encoded in base %b
str, err := cid.StringOfBase(base)
if err != nil {
return "", err
}
out.WriteString(str)
case 'S': // cid string without base prefix
out.WriteString(encode(encoder, cid.Bytes(), true))
case 'P': // prefix
fmt.Fprintf(out, "cidv%d-%s-%s-%d",
p.Version,
codecToString(p.Codec),
hashToString(p.MhType),
p.MhLength,
)
default:
return "", FormatStringError{"unrecognized specifier in format string", fmtStr[i-1 : i+1]}
}

}
return out.String(), err
}

func baseToString(base mb.Encoding) string {
baseStr, ok := mb.EncodingToStr[base]
if !ok {
return fmt.Sprintf("base?%c", base)
}
return baseStr
}

func codecToString(num uint64) string {
name, ok := c.CodecToStr[num]
if !ok {
return fmt.Sprintf("codec?%d", num)
}
return name
}

func hashToString(num uint64) string {
name, ok := mh.Codes[num]
if !ok {
return fmt.Sprintf("hash?%d", num)
}
return name
}

func encode(base mb.Encoder, data []byte, strip bool) string {
str := base.Encode(data)
if strip {
return str[1:]
}
return str
}

func toCidV0(cid *c.Cid) (*c.Cid, error) {
if cid.Type() != c.DagProtobuf {
return nil, fmt.Errorf("can't convert non-protobuf nodes to cidv0")
Expand Down
70 changes: 3 additions & 67 deletions cid-fmt/main_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,77 +4,13 @@ import (
"fmt"
"testing"

mb "github.com/multiformats/go-multibase"
c "github.com/ipfs/go-cid"
)

func TestFmt(t *testing.T) {
cids := map[string]string{
"cidv0": "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn",
"cidv1": "zdj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD",
}
tests := []struct {
cidId string
newBase mb.Encoding
fmtStr string
result string
}{
{"cidv0", -1, "%P", "cidv0-protobuf-sha2-256-32"},
{"cidv0", -1, "%b-%v-%c-%h-%L", "base58btc-cidv0-protobuf-sha2-256-32"},
{"cidv0", -1, "%s", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
{"cidv0", -1, "%S", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
{"cidv0", -1, "ver#%V/#%C/#%H/%L", "ver#0/#112/#18/32"},
{"cidv0", -1, "%m", "zQmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
{"cidv0", -1, "%M", "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"},
{"cidv0", -1, "%d", "z72gdmFAgRzYHkJzKiL8MgMMRW3BTSCGyDHroPxJbxMJn"},
{"cidv0", -1, "%D", "72gdmFAgRzYHkJzKiL8MgMMRW3BTSCGyDHroPxJbxMJn"},
{"cidv0", 'B', "%S", "CIQFTFEEHEDF6KLBT32BFAGLXEZL4UWFNWM4LFTLMXQBCERZ6CMLX3Y"},
{"cidv0", 'B', "%B%S", "BCIQFTFEEHEDF6KLBT32BFAGLXEZL4UWFNWM4LFTLMXQBCERZ6CMLX3Y"},
{"cidv1", -1, "%P", "cidv1-protobuf-sha2-256-32"},
{"cidv1", -1, "%b-%v-%c-%h-%L", "base58btc-cidv1-protobuf-sha2-256-32"},
{"cidv1", -1, "%s", "zdj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD"},
{"cidv1", -1, "%S", "dj7WfLr9DhLrb1hsoSi4fSdjjxuZmeqgEtBPWxMLtPbDNbFD"},
{"cidv1", -1, "ver#%V/#%C/#%H/%L", "ver#1/#112/#18/32"},
{"cidv1", -1, "%m", "zQmYFbmndVP7QqAVWyKhpmMuQHMaD88pkK57RgYVimmoh5H"},
{"cidv1", -1, "%M", "QmYFbmndVP7QqAVWyKhpmMuQHMaD88pkK57RgYVimmoh5H"},
{"cidv1", -1, "%d", "zAux4gVVsLRMXtsZ9fd3tFEZN4jGYB6kP37fgoZNTc11H"},
{"cidv1", -1, "%D", "Aux4gVVsLRMXtsZ9fd3tFEZN4jGYB6kP37fgoZNTc11H"},
{"cidv1", 'B', "%s", "BAFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
{"cidv1", 'B', "%S", "AFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
{"cidv1", 'B', "%B%S", "BAFYBEIETJGSRL3EQPQPCABV3G6IUBYTSIFVQ24XRRHD3JUETSKLTGQ7DJA"},
}
for _, tc := range tests {
name := fmt.Sprintf("%s/%s", tc.cidId, tc.fmtStr)
if tc.newBase != -1 {
name = fmt.Sprintf("%s/%c", name, tc.newBase)
}
cidStr := cids[tc.cidId]
t.Run(name, func(t *testing.T) {
testFmt(t, cidStr, tc.newBase, tc.fmtStr, tc.result)
})
}
}

func testFmt(t *testing.T, cidStr string, newBase mb.Encoding, fmtStr string, result string) {
base, cid, err := decode(cidStr)
if newBase != -1 {
base = newBase
}
if err != nil {
t.Fatal(err)
}
str, err := fmtCid(fmtStr, base, cid)
if err != nil {
t.Fatal(err)
}
if str != result {
t.Error(fmt.Sprintf("expected: %s; but got: %s", result, str))
}
}

func TestCidConv(t *testing.T) {
cidv0 := "QmUNLLsPACCz1vLxQVkXqqLX5R1X345qqfHbsf67hvA3Nn"
cidv1 := "zdj7WbTaiJT1fgatdet9Ei9iDB5hdCxkbVyhyh8YTUnXMiwYi"
_, cid, err := decode(cidv0)
_, cid, err := c.DecodeV2(cidv0)
if err != nil {
t.Fatal(err)
}
Expand All @@ -98,7 +34,7 @@ func TestCidConv(t *testing.T) {
func TestBadCidConv(t *testing.T) {
// this cid is a raw leaf and should not be able to convert to cidv0
cidv1 := "zb2rhhzX7uSKrtQ2ZZXFAabKiKFYZrJqKY2KE1cJ8yre2GSWZ"
_, cid, err := decode(cidv1)
_, cid, err := c.DecodeV2(cidv1)
if err != nil {
t.Fatal(err)
}
Expand Down
21 changes: 15 additions & 6 deletions cid.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -213,25 +213,34 @@ func Parse(v interface{}) (*Cid, error) {
// starting with "Qm" are considered CidV0 and treated directly
// as B58-encoded multihashes.
func Decode(v string) (*Cid, error) {
_, cid, err := DecodeV2(v)
return cid, err
}

// DecodeV2 is like Decide but also returns the Multibase encoding the
// Cid was encoded in. EXPERIMENTAL and interface may change at any time.
func DecodeV2(v string) (mbase.Encoding, *Cid, error) {
if len(v) < 2 {
return nil, ErrCidTooShort
return 0, nil, ErrCidTooShort
}

if len(v) == 46 && v[:2] == "Qm" {
hash, err := mh.FromB58String(v)
if err != nil {
return nil, err
return 0, nil, err
}

return NewCidV0(hash), nil
return mbase.Base58BTC, NewCidV0(hash), nil
}

_, data, err := mbase.Decode(v)
base, data, err := mbase.Decode(v)
if err != nil {
return nil, err
return 0, nil, err
}

return Cast(data)
cid, err := Cast(data)

return base, cid, err
}

func uvError(read int) error {
Expand Down
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