// CountP2SHSigOps returns the number of signature operations for all input
// transactions which are of the pay-to-script-hash type. This uses the
// precise, signature operation counting mechanism from the script engine which
// requires access to the input transaction scripts.
func CountP2SHSigOps(tx *coinutil.Tx, isCoinBaseTx bool, txStore TxStore) (int, error) {
// Coinbase transactions have no interesting inputs.
if isCoinBaseTx {
return 0, nil
}
// Accumulate the number of signature operations in all transaction
// inputs.
msgTx := tx.MsgTx()
totalSigOps := 0
for _, txIn := range msgTx.TxIn {
// Ensure the referenced input transaction is available.
txInHash := &txIn.PreviousOutPoint.Hash
originTx, exists := txStore[*txInHash]
if !exists || originTx.Err != nil || originTx.Tx == nil {
str := fmt.Sprintf("unable to find input transaction "+
"%v referenced from transaction %v", txInHash,
tx.Sha())
return 0, ruleError(ErrMissingTx, str)
}
originMsgTx := originTx.Tx.MsgTx()
// Ensure the output index in the referenced transaction is
// available.
originTxIndex := txIn.PreviousOutPoint.Index
if originTxIndex >= uint32(len(originMsgTx.TxOut)) {
str := fmt.Sprintf("out of bounds input index %d in "+
"transaction %v referenced from transaction %v",
originTxIndex, txInHash, tx.Sha())
return 0, ruleError(ErrBadTxInput, str)
}
// We're only interested in pay-to-script-hash types, so skip
// this input if it's not one.
pkScript := originMsgTx.TxOut[originTxIndex].PkScript
if !txscript.IsPayToScriptHash(pkScript) {
continue
}
// Count the precise number of signature operations in the
// referenced public key script.
sigScript := txIn.SignatureScript
numSigOps := txscript.GetPreciseSigOpCount(sigScript, pkScript,
true)
// We could potentially overflow the accumulator so check for
// overflow.
lastSigOps := totalSigOps
totalSigOps += numSigOps
if totalSigOps < lastSigOps {
str := fmt.Sprintf("the public key script from "+
"output index %d in transaction %v contains "+
"too many signature operations - overflow",
originTxIndex, txInHash)
return 0, ruleError(ErrTooManySigOps, str)
}
}
return totalSigOps, nil
}
// TestIsPayToScriptHash ensures the IsPayToScriptHash function returns the
// expected results for all the scripts in scriptClassTests.
func TestIsPayToScriptHash(t *testing.T) {
t.Parallel()
for _, test := range scriptClassTests {
script := mustParseShortForm(test.script)
shouldBe := (test.class == txscript.ScriptHashTy)
p2sh := txscript.IsPayToScriptHash(script)
if p2sh != shouldBe {
t.Errorf("%s: epxected p2sh %v, got %v", test.name,
shouldBe, p2sh)
}
}
}