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fq/format/bitcoin/bitcoin_transaction.go
Platon Pronko a3361e70ba bitcoin: fix witness item structs
This commit fixes witness item decoding such that they are represented
as structs with `item_size` and `item` fields, instead of a flat list
of raw bytes.
2023-05-15 18:36:26 +08:00

106 lines
2.8 KiB
Go

package bitcoin
// TODO: coinbase transaction
// https://learnmeabitcoin.com/technical/blkdat
import (
"github.com/wader/fq/format"
"github.com/wader/fq/pkg/decode"
"github.com/wader/fq/pkg/interp"
"github.com/wader/fq/pkg/scalar"
)
var bitcoinScriptGroup decode.Group
func init() {
interp.RegisterFormat(
format.Bitcoin_Transaction,
&decode.Format{
Description: "Bitcoin transaction",
Dependencies: []decode.Dependency{
{Groups: []*decode.Group{format.Bitcoin_Script}, Out: &bitcoinScriptGroup},
},
DecodeFn: decodeBitcoinTranscation,
})
}
// Prefix with fd, and the next 2 bytes is the VarInt (in little-endian).
// Prefix with fe, and the next 4 bytes is the VarInt (in little-endian).
// Prefix with ff, and the next 8 bytes is the VarInt (in little-endian).
func decodeVarInt(d *decode.D) uint64 {
n := d.U8()
switch n {
case 0xfd:
return d.U16()
case 0xfe:
return d.U32()
case 0xff:
return d.U64()
default:
return n
}
}
// all zero
var txIDCoinbaseBytes = [32]byte{}
func decodeBitcoinTranscation(d *decode.D) any {
d.Endian = decode.LittleEndian
d.FieldU32("version")
witness := false
if d.PeekUintBits(8) == 0 {
witness = true
d.FieldU8("marker")
d.FieldU8("flag")
}
inputCount := d.FieldUintFn("input_count", decodeVarInt)
d.FieldArray("inputs", func(d *decode.D) {
for i := uint64(0); i < inputCount; i++ {
d.FieldStruct("input", func(d *decode.D) {
d.FieldRawLen("txid", 32*8, scalar.RawBytesMap{
{Bytes: txIDCoinbaseBytes[:], Scalar: scalar.BitBuf{Description: "coinbase"}},
}, rawHexReverse)
d.FieldU32("vout")
scriptSigSize := d.FieldUintFn("scriptsig_size", decodeVarInt)
d.FieldFormatOrRawLen("scriptsig", int64(scriptSigSize)*8, &bitcoinScriptGroup, nil)
// TODO: better way to know if there should be a valid script
d.FieldU32("sequence", scalar.UintHex)
})
}
})
outputCount := d.FieldUintFn("output_count", decodeVarInt)
d.FieldArray("outputs", func(d *decode.D) {
for i := uint64(0); i < outputCount; i++ {
d.FieldStruct("output", func(d *decode.D) {
d.FieldU64("value")
scriptSigSize := d.FieldUintFn("scriptpub_size", decodeVarInt)
// TODO: better way to know if there should be a valid script
d.FieldFormatOrRawLen("scriptpub", int64(scriptSigSize)*8, &bitcoinScriptGroup, nil)
})
}
})
if witness {
d.FieldArray("witnesses", func(d *decode.D) {
for i := uint64(0); i < inputCount; i++ {
d.FieldStruct("witness", func(d *decode.D) {
witnessSize := d.FieldUintFn("witness_size", decodeVarInt)
d.FieldArray("items", func(d *decode.D) {
for j := uint64(0); j < witnessSize; j++ {
d.FieldStruct("item", func(d *decode.D) {
itemSize := d.FieldUintFn("item_size", decodeVarInt)
d.FieldRawLen("item", int64(itemSize)*8)
})
}
})
})
}
})
}
d.FieldU32("locktime")
return nil
}