From 6409879e14fd99d6810e2775bfc005bc0eceb8f6 Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Mon, 29 Jul 2013 16:18:15 -0500
Subject: [PATCH] Modify count sigops calls for new btcscript API.

The btcscript API for GetSigOpCount and GetPreciseSigOpCount
recently changed to no longer return an error.  This change was necessary
to mirror the behavior of bitcoind signature operations counting.  This
commit modifies the code accordingly to use the new API.
---
 validate.go | 65 +++++++++++++++--------------------------------------
 1 file changed, 18 insertions(+), 47 deletions(-)

diff --git a/validate.go b/validate.go
index 114dd19b..541bb67c 100644
--- a/validate.go
+++ b/validate.go
@@ -304,37 +304,23 @@ func (b *BlockChain) checkProofOfWork(block *btcutil.Block) error {
 // input and output scripts in the provided transaction.  This uses the
 // quicker, but imprecise, signature operation counting mechanism from
 // btcscript.
-func countSigOps(msgTx *btcwire.MsgTx, isCoinBaseTx bool) (int, error) {
-	// Choose the starting transaction input based on whether this is a
-	// coinbase transaction since the coinbase input script should not be
-	// executed.
-	txIns := msgTx.TxIn
-	if isCoinBaseTx {
-		txIns = txIns[1:]
-	}
-
+func countSigOps(msgTx *btcwire.MsgTx) int {
 	// Accumulate the number of signature operations in all transaction
-	// inputs (except the first input if this is a coinbase transaction).
+	// inputs.
 	totalSigOps := 0
-	for _, txIn := range txIns {
-		numSigOps, err := btcscript.GetSigOpCount(txIn.SignatureScript)
-		if err != nil {
-			return 0, err
-		}
+	for _, txIn := range msgTx.TxIn {
+		numSigOps := btcscript.GetSigOpCount(txIn.SignatureScript)
 		totalSigOps += numSigOps
 	}
 
 	// Accumulate the number of signature operations in all transaction
 	// outputs.
 	for _, txOut := range msgTx.TxOut {
-		numSigOps, err := btcscript.GetSigOpCount(txOut.PkScript)
-		if err != nil {
-			return 0, err
-		}
+		numSigOps := btcscript.GetSigOpCount(txOut.PkScript)
 		totalSigOps += numSigOps
 	}
 
-	return totalSigOps, nil
+	return totalSigOps
 }
 
 // countP2SHSigOps returns the number of signature operations for all input
@@ -360,7 +346,7 @@ func countP2SHSigOps(msgTx *btcwire.MsgTx, isCoinBaseTx bool, txStore map[btcwir
 		// Ensure the referenced input transaction is available.
 		txInHash := &txIn.PreviousOutpoint.Hash
 		originTx, exists := txStore[*txInHash]
-		if !exists {
+		if !exists || originTx.err != nil || originTx.tx == nil {
 			return 0, fmt.Errorf("unable to find input transaction "+
 				"%v referenced from transaction %v", txHash,
 				txInHash)
@@ -385,11 +371,8 @@ func countP2SHSigOps(msgTx *btcwire.MsgTx, isCoinBaseTx bool, txStore map[btcwir
 		// Count the precise number of signature operations in the
 		// referenced public key script.
 		sigScript := txIn.SignatureScript
-		numSigOps, err := btcscript.GetPreciseSigOpCount(sigScript,
-			pkScript, true)
-		if err != nil {
-			return 0, err
-		}
+		numSigOps := btcscript.GetPreciseSigOpCount(sigScript, pkScript,
+			true)
 
 		// We could potentially overflow the accumulator so check for
 		// overflow.
@@ -492,21 +475,11 @@ func (b *BlockChain) checkBlockSanity(block *btcutil.Block) error {
 	// The number of signature operations must be less than the maximum
 	// allowed per block.
 	totalSigOps := 0
-	for i, tx := range transactions {
-		// Since the first (and only the first) transaction has already
-		// been verified above to be a coinbase transaction, use i == 0
-		// as an optimization for the flag to countSigOps for whether
-		// or not the transaction is a coinbase transaction rather than
-		// having to do a full coinbase check again.
-		numSigOps, err := countSigOps(tx, i == 0)
-		if err != nil {
-			return err
-		}
-
+	for _, tx := range transactions {
 		// We could potentially overflow the accumulator so check for
 		// overflow.
 		lastSigOps := totalSigOps
-		totalSigOps += numSigOps
+		totalSigOps += countSigOps(tx)
 		if totalSigOps < lastSigOps || totalSigOps > maxSigOpsPerBlock {
 			str := fmt.Sprintf("block contains too many signature "+
 				"operations - got %v, max %v", totalSigOps,
@@ -783,16 +756,14 @@ func (b *BlockChain) checkConnectBlock(node *blockNode, block *btcutil.Block) er
 	transactions := block.MsgBlock().Transactions
 	totalSigOps := 0
 	for i, tx := range transactions {
-		// Since the first (and only the first) transaction has already
-		// been verified to be a coinbase transaction, use i == 0
-		// as an optimization for the flag to countSigOps for whether
-		// or not the transaction is a coinbase transaction rather than
-		// having to do a full coinbase check again.
-		numsigOps, err := countSigOps(tx, i == 0)
-		if err != nil {
-			return err
-		}
+		numsigOps := countSigOps(tx)
 		if enforceBIP0016 {
+			// Since the first (and only the first) transaction has
+			// already been verified to be a coinbase transaction,
+			// use i == 0 as an optimization for the flag to
+			// countP2SHSigOps for whether or not the transaction is
+			// a coinbase transaction rather than having to do a
+			// full coinbase check again.
 			numP2SHSigOps, err := countP2SHSigOps(tx, i == 0,
 				txInputStore)
 			if err != nil {