Parse dependencies

andybalholm

Mar 29, 2023, 12:16 AM

4JWXOJIPJAOL6FZMQENB2ZUTWEFXNB7VU2NHYDNT4T45ESSCSUPQC

Dependencies

• [2] 7VEHGTEY Switch from reading text format to reading binary format.
• [*] EKAB33DH Start using some parser combinators
• [*] PHRWK7NK Parse change headers

Change contents

• edit in combinators.go at line 268
  [2.6658]

  [2.6658]
  + }

  +

  + func uint32LE(input []byte) ([]byte, uint32, error) {

  + if len(input) < 4 {

  + return input, 0, fmt.Errorf("need 4 bytes to parse a 32-bit integer; only got %d", len(input))

  + }

  + return input[4:], binary.LittleEndian.Uint32(input), nil
• edit in combinators.go at line 361
  [2.8704]

  [2.8704]
  + }

  + }

  +

  + func take(n int) parser[[]byte] {

  + return func(data []byte) ([]byte, []byte, error) {

  + if n > len(data) {

  + return data, nil, io.ErrUnexpectedEOF

  + }

  + return data[n:], data[:n], nil
• edit in change_test.go at line 22
  [5.701]

  [5.1094]
  + Dependencies: []Hash{Hash{0xe7, 0x82, 0xb1, 0xd7, 0xe4, 0x17, 0x64, 0xe4, 0xfe, 0x45, 0x2d, 0x6f, 0x24, 0x22, 0x40, 0x26, 0x16, 0x12, 0xb7, 0xf, 0x42, 0x70, 0xd9, 0xac, 0xd8, 0x4e, 0x5a, 0x82, 0xea, 0x85, 0xab, 0x57}},

  + ExtraKnown: []Hash{},

  + Metadata: []byte{},
• edit in change_test.go at line 34
  [2.9330]

  [5.1402]
  + }

  + }

  +

  + func TestHashBase32(t *testing.T) {

  + hs := "CB7A3PP3XC6JY3QYUUNB4WCXGNFJMHTTH54MBAWBUVQL7TTHWBBQC"

  + hash, err := HashFromBase32(hs)

  + if err != nil {

  + t.Fatalf("error parsing hash: %v", err)
• edit in change_test.go at line 43
  [5.1405]

  [5.1405]
  + if hash.String() != hs {

  + t.Fatalf("got %s, want %s", hash.String(), hs)

  + }
• edit in change.go at line 5
  [2.774]

  [2.774]
  + "encoding/base32"
• replacement in change.go at line 15
  [2.877]→[2.877:993](∅→∅)
  − Version uint64

  − Message string

  − Description string

  − Timestamp time.Time

  − Authors []map[string]string
  [2.877]

  [2.993]
  + Version uint64

  + Message string

  + Description string

  + Timestamp time.Time

  + Authors []map[string]string

  + Dependencies []Hash

  + ExtraKnown []Hash

  + Metadata []byte

  + }

  +

  + type Hash [32]byte

  +

  + var base32Encoding = base32.StdEncoding.WithPadding(base32.NoPadding)

  +

  + func (h Hash) String() string {

  + return base32Encoding.EncodeToString(append(h[:], 1))
• edit in change.go at line 33
  [2.996]

  [2.996]
  + func HashFromBase32(b32 string) (Hash, error) {

  + b, err := base32Encoding.DecodeString(b32)

  + if err != nil {

  + return Hash{}, err

  + }

  + if len(b) != 33 {

  + return Hash{}, fmt.Errorf("expected 33 bytes, got %d", len(b))

  + }

  + if b[32] != 1 {

  + return Hash{}, fmt.Errorf("expected Blake3 hash, got type %d", b[32])

  + }

  + return Hash(b[:32]), nil

  + }

  +
• replacement in change.go at line 65
  [2.1427]→[2.1427:1458](∅→∅)
  − zr, err := zstd.NewReader(br)
  [2.1427]

  [2.1458]
  + zr, err := zstd.NewReader(bytes.NewReader(data[binary.Size(offsets{}):off.UnhashedOffset]))
• edit in change.go at line 94
  [2.2118]

  [2.2118]
  +
• edit in change.go at line 99
  [2.2212]

  [2.2212]
  +
• edit in change.go at line 107
  [2.2376]

  [2.2376]
  +
• edit in change.go at line 114
  [2.2601]

  [2.2601]
  +
• edit in change.go at line 116
  [2.2708]

  [2.2708]
  + if err != nil {

  + return err

  + }

  +

  + data, c.Dependencies, err = vec(deserializeHash)(data)
• replacement in change.go at line 125
  [2.2742]→[2.2742:2750](∅→∅)
  − //TODO
  [2.2742]

  [2.2750]
  + data, c.ExtraKnown, err = vec(deserializeHash)(data)

  + if err != nil {

  + return err

  + }

  +

  + data, c.Metadata, err = lengthData(uint64LE)(data)

  + if err != nil {

  + return err

  + }
• edit in change.go at line 138
  [2.2766]

  [2.2766]
  + func deserializeHash(data []byte) ([]byte, Hash, error) {

  + data, tag, err := uint32LE(data)

  + if err != nil {

  + return data, Hash{}, err

  + }

  + if tag == 0 {

  + return data, Hash{}, nil

  + }

  + if tag != 1 {

  + return data, Hash{}, fmt.Errorf("bad tag for Hash, expected 0 or 1, got %d", tag)

  + }

  + data, b, err := take(32)(data)

  + if err != nil {

  + return data, Hash{}, err

  + }

  + return data, Hash(b), nil

  + }

  +