// createCoinbaseTx returns a coinbase transaction paying an appropriate subsidy
// based on the passed block height to the provided address. When the address
// is nil, the coinbase transaction will instead be redeemable by anyone.
//
// See the comment for NewBlockTemplate for more information about why the nil
// address handling is useful.
func createCoinbaseTx(params *chaincfg.Params, coinbaseScript []byte, nextBlockHeight int32, addr btcutil.Address) (*btcutil.Tx, error) {
// Create the script to pay to the provided payment address if one was
// specified. Otherwise create a script that allows the coinbase to be
// redeemable by anyone.
var pkScript []byte
if addr != nil {
var err error
pkScript, err = txscript.PayToAddrScript(addr)
if err != nil {
return nil, err
}
} else {
var err error
scriptBuilder := txscript.NewScriptBuilder()
pkScript, err = scriptBuilder.AddOp(txscript.OP_TRUE).Script()
if err != nil {
return nil, err
}
}
tx := wire.NewMsgTx(wire.TxVersion)
tx.AddTxIn(&wire.TxIn{
// Coinbase transactions have no inputs, so previous outpoint is
// zero hash and max index.
PreviousOutPoint: *wire.NewOutPoint(&chainhash.Hash{},
wire.MaxPrevOutIndex),
SignatureScript: coinbaseScript,
Sequence: wire.MaxTxInSequenceNum,
})
tx.AddTxOut(&wire.TxOut{
Value: blockchain.CalcBlockSubsidy(nextBlockHeight, params),
PkScript: pkScript,
})
return btcutil.NewTx(tx), nil
}
// createCoinbaseTx returns a coinbase transaction paying an appropriate
// subsidy based on the passed block height to the provided address.
func createCoinbaseTx(coinbaseScript []byte, nextBlockHeight int32,
addr btcutil.Address, net *chaincfg.Params) (*btcutil.Tx, error) {
// Create the script to pay to the provided payment address.
pkScript, err := txscript.PayToAddrScript(addr)
if err != nil {
return nil, err
}
tx := wire.NewMsgTx()
tx.AddTxIn(&wire.TxIn{
// Coinbase transactions have no inputs, so previous outpoint is
// zero hash and max index.
PreviousOutPoint: *wire.NewOutPoint(&chainhash.Hash{},
wire.MaxPrevOutIndex),
SignatureScript: coinbaseScript,
Sequence: wire.MaxTxInSequenceNum,
})
tx.AddTxOut(&wire.TxOut{
Value: blockchain.CalcBlockSubsidy(nextBlockHeight, net),
PkScript: pkScript,
})
return btcutil.NewTx(tx), nil
}
// CreateCoinbaseTx returns a coinbase transaction with the requested number of
// outputs paying an appropriate subsidy based on the passed block height to the
// address associated with the harness. It automatically uses a standard
// signature script that starts with the block height that is required by
// version 2 blocks.
func (p *poolHarness) CreateCoinbaseTx(blockHeight int32, numOutputs uint32) (*btcutil.Tx, error) {
// Create standard coinbase script.
extraNonce := int64(0)
coinbaseScript, err := txscript.NewScriptBuilder().
AddInt64(int64(blockHeight)).AddInt64(extraNonce).Script()
if err != nil {
return nil, err
}
tx := wire.NewMsgTx(wire.TxVersion)
tx.AddTxIn(&wire.TxIn{
// Coinbase transactions have no inputs, so previous outpoint is
// zero hash and max index.
PreviousOutPoint: *wire.NewOutPoint(&chainhash.Hash{},
wire.MaxPrevOutIndex),
SignatureScript: coinbaseScript,
Sequence: wire.MaxTxInSequenceNum,
})
totalInput := blockchain.CalcBlockSubsidy(blockHeight, p.chainParams)
amountPerOutput := totalInput / int64(numOutputs)
remainder := totalInput - amountPerOutput*int64(numOutputs)
for i := uint32(0); i < numOutputs; i++ {
// Ensure the final output accounts for any remainder that might
// be left from splitting the input amount.
amount := amountPerOutput
if i == numOutputs-1 {
amount = amountPerOutput + remainder
}
tx.AddTxOut(&wire.TxOut{
PkScript: p.payScript,
Value: amount,
})
}
return btcutil.NewTx(tx), nil
}