[DEV-126] Get rid of tfSpent in txoFlags (#69)

blockdag/dagio.go

@@ -482,10 +482,7 @@ func recycleOutpointKey(key *[]byte) {
 
 // utxoEntryHeaderCode returns the calculated header code to be used when
 // serializing the provided utxo entry.
-func utxoEntryHeaderCode(entry *UTXOEntry) (uint64, error) {
-	if entry.IsSpent() {
-		return 0, AssertError("attempt to serialize spent UTXO header")
-	}
+func utxoEntryHeaderCode(entry *UTXOEntry) uint64 {
 
 	// As described in the serialization format comments, the header code
 	// encodes the height shifted over one bit and the coinbase flag in the
@@ -495,22 +492,15 @@ func utxoEntryHeaderCode(entry *UTXOEntry) (uint64, error) {
 		headerCode |= 0x01
 	}
 
-	return headerCode, nil
+	return headerCode
 }
 
 // serializeUTXOEntry returns the entry serialized to a format that is suitable
 // for long-term storage.  The format is described in detail above.
 func serializeUTXOEntry(entry *UTXOEntry) ([]byte, error) {
-	// Spent outputs have no serialization.
-	if entry.IsSpent() {
-		return nil, nil
-	}
 
 	// Encode the header code.
-	headerCode, err := utxoEntryHeaderCode(entry)
-	if err != nil {
-		return nil, err
-	}
+	headerCode := utxoEntryHeaderCode(entry)
 
 	// Calculate the size needed to serialize the entry.
 	size := serializeSizeVLQ(headerCode) +

blockdag/dagio_test.go

@@ -426,18 +426,6 @@ func TestUtxoSerialization(t *testing.T) {
 			serialized: hexToBytes("03320496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52"),
 		},
 		// From tx in main blockchain:
-		// b7c3332bc138e2c9429818f5fed500bcc1746544218772389054dc8047d7cd3f:0
-		{
-			name: "height 1, coinbase, spent",
-			entry: &UTXOEntry{
-				amount:      5000000000,
-				pkScript:    hexToBytes("410496b538e853519c726a2c91e61ec11600ae1390813a627c66fb8be7947be63c52da7589379515d4e0a604f8141781e62294721166bf621e73a82cbf2342c858eeac"),
-				blockHeight: 1,
-				packedFlags: tfCoinBase | tfSpent,
-			},
-			serialized: nil,
-		},
-		// From tx in main blockchain:
 		// 8131ffb0a2c945ecaf9b9063e59558784f9c3a74741ce6ae2a18d0571dac15bb:1
 		{
 			name: "height 100001, not coinbase",
@@ -449,18 +437,6 @@ func TestUtxoSerialization(t *testing.T) {
 			},
 			serialized: hexToBytes("8b99420700ee8bd501094a7d5ca318da2506de35e1cb025ddc"),
 		},
-		// From tx in main blockchain:
-		// 8131ffb0a2c945ecaf9b9063e59558784f9c3a74741ce6ae2a18d0571dac15bb:1
-		{
-			name: "height 100001, not coinbase, spent",
-			entry: &UTXOEntry{
-				amount:      1000000,
-				pkScript:    hexToBytes("76a914ee8bd501094a7d5ca318da2506de35e1cb025ddc88ac"),
-				blockHeight: 100001,
-				packedFlags: tfSpent,
-			},
-			serialized: nil,
-		},
 	}
 
 	for i, test := range tests {
@@ -478,12 +454,6 @@ func TestUtxoSerialization(t *testing.T) {
 			continue
 		}
 
-		// Don't try to deserialize if the test entry was spent since it
-		// will have a nil serialization.
-		if test.entry.IsSpent() {
-			continue
-		}
-
 		// Deserialize to a utxo entry.
 		utxoEntry, err := deserializeUTXOEntry(test.serialized)
 		if err != nil {
@@ -492,14 +462,6 @@ func TestUtxoSerialization(t *testing.T) {
 			continue
 		}
 
-		// The deserialized entry must not be marked spent since unspent
-		// entries are not serialized.
-		if utxoEntry.IsSpent() {
-			t.Errorf("deserializeUTXOEntry #%d (%s) output should "+
-				"not be marked spent", i, test.name)
-			continue
-		}
-
 		// Ensure the deserialized entry has the same properties as the
 		// ones in the test entry.
 		if utxoEntry.Amount() != test.entry.Amount() {
@@ -530,41 +492,6 @@ func TestUtxoSerialization(t *testing.T) {
 	}
 }
 
-// TestUtxoEntryHeaderCodeErrors performs negative tests against unspent
-// transaction output header codes to ensure error paths work as expected.
-func TestUtxoEntryHeaderCodeErrors(t *testing.T) {
-	t.Parallel()
-
-	tests := []struct {
-		name    string
-		entry   *UTXOEntry
-		code    uint64
-		errType error
-	}{
-		{
-			name:    "Force assertion due to spent output",
-			entry:   &UTXOEntry{packedFlags: tfSpent},
-			errType: AssertError(""),
-		},
-	}
-
-	for _, test := range tests {
-		// Ensure the expected error type is returned and the code is 0.
-		code, err := utxoEntryHeaderCode(test.entry)
-		if reflect.TypeOf(err) != reflect.TypeOf(test.errType) {
-			t.Errorf("utxoEntryHeaderCode (%s): expected error "+
-				"type does not match - got %T, want %T",
-				test.name, err, test.errType)
-			continue
-		}
-		if code != 0 {
-			t.Errorf("utxoEntryHeaderCode (%s): unexpected code "+
-				"on error - got %d, want 0", test.name, code)
-			continue
-		}
-	}
-}
-
 // TestUtxoEntryDeserializeErrors performs negative tests against deserializing
 // unspent transaction outputs to ensure error paths work as expected.
 func TestUtxoEntryDeserializeErrors(t *testing.T) {

blockdag/utxoset.go

@@ -42,24 +42,6 @@ func (entry *UTXOEntry) BlockHeight() int32 {
 	return entry.blockHeight
 }
 
-// IsSpent returns whether or not the output has been spent based upon the
-// current state of the unspent transaction output view it was obtained from.
-func (entry *UTXOEntry) IsSpent() bool {
-	return entry.packedFlags&tfSpent == tfSpent
-}
-
-// Spend marks the output as spent.  Spending an output that is already spent
-// has no effect.
-func (entry *UTXOEntry) Spend() {
-	// Nothing to do if the output is already spent.
-	if entry.IsSpent() {
-		return
-	}
-
-	// Mark the output as spent.
-	entry.packedFlags |= tfSpent
-}
-
 // Amount returns the amount of the output.
 func (entry *UTXOEntry) Amount() int64 {
 	return entry.amount
@@ -91,9 +73,6 @@ type txoFlags uint8
 const (
 	// tfCoinBase indicates that a txout was contained in a coinbase tx.
 	tfCoinBase txoFlags = 1 << iota
-
-	// tfSpent indicates that a txout is spent.
-	tfSpent
 )
 
 // utxoCollection represents a set of UTXOs indexed by their outPoints

blockdag/validate.go

@@ -349,7 +349,7 @@ func CountP2SHSigOps(tx *util.Tx, isCoinBaseTx bool, utxoSet UTXOSet) (int, erro
 	for txInIndex, txIn := range msgTx.TxIn {
 		// Ensure the referenced input transaction is available.
 		entry, ok := utxoSet.Get(txIn.PreviousOutPoint)
-		if !ok || entry.IsSpent() {
+		if !ok {
 			str := fmt.Sprintf("output %v referenced from "+
 				"transaction %s:%d either does not exist or "+
 				"has already been spent", txIn.PreviousOutPoint,
@@ -792,7 +792,7 @@ func (dag *BlockDAG) ensureNoDuplicateTx(node *blockNode, block *util.Block) err
 	// is fully spent.
 	for outpoint := range fetchSet {
 		utxo, ok := dag.virtual.GetUTXOEntry(outpoint)
-		if ok && !utxo.IsSpent() {
+		if ok {
 			str := fmt.Sprintf("tried to overwrite transaction %v "+
 				"at block height %d that is not fully spent",
 				outpoint.Hash, utxo.BlockHeight())
@@ -825,7 +825,7 @@ func CheckTransactionInputs(tx *util.Tx, txHeight int32, utxoSet UTXOSet, dagPar
 	for txInIndex, txIn := range tx.MsgTx().TxIn {
 		// Ensure the referenced input transaction is available.
 		entry, ok := utxoSet.Get(txIn.PreviousOutPoint)
-		if !ok || entry.IsSpent() {
+		if !ok {
 			str := fmt.Sprintf("output %v referenced from "+
 				"transaction %s:%d either does not exist or "+
 				"has already been spent", txIn.PreviousOutPoint,

mempool/mempool.go

@@ -709,8 +709,8 @@ func (mp *TxPool) maybeAcceptTransaction(tx *util.Tx, isNew, rateLimit, rejectDu
 	prevOut := wire.OutPoint{Hash: *txHash}
 	for txOutIdx := range tx.MsgTx().TxOut {
 		prevOut.Index = uint32(txOutIdx)
-		entry, ok := mp.mpUTXOSet.Get(prevOut)
-		if ok && !entry.IsSpent() {
+		_, ok := mp.mpUTXOSet.Get(prevOut)
+		if ok {
 			return nil, nil, txRuleError(wire.RejectDuplicate,
 				"transaction already exists")
 		}

mining/mining.go

@@ -486,8 +486,8 @@ mempoolLoop:
 		prioItem := &txPrioItem{tx: tx}
 		for _, txIn := range tx.MsgTx().TxIn {
 			originHash := &txIn.PreviousOutPoint.Hash
-			entry, ok := blockUtxos.Get(txIn.PreviousOutPoint)
-			if !ok || entry.IsSpent() {
+			_, ok := blockUtxos.Get(txIn.PreviousOutPoint)
+			if !ok {
 				if !g.txSource.HaveTransaction(originHash) {
 					log.Tracef("Skipping tx %s because it "+
 						"references unspent output %s "+
@@ -716,12 +716,12 @@ mempoolLoop:
 	merkles := blockdag.BuildMerkleTreeStore(blockTxns)
 	var msgBlock wire.MsgBlock
 	msgBlock.Header = wire.BlockHeader{
-		Version:    nextBlockVersion,
+		Version:       nextBlockVersion,
 		NumPrevBlocks: byte(len(virtualBlock.TipHashes())),
-		PrevBlocks: virtualBlock.TipHashes(),
-		MerkleRoot: *merkles[len(merkles)-1],
-		Timestamp:  ts,
-		Bits:       reqDifficulty,
+		PrevBlocks:    virtualBlock.TipHashes(),
+		MerkleRoot:    *merkles[len(merkles)-1],
+		Timestamp:     ts,
+		Bits:          reqDifficulty,
 	}
 	for _, tx := range blockTxns {
 		if err := msgBlock.AddTransaction(tx.MsgTx()); err != nil {

mining/policy.go

@@ -60,7 +60,7 @@ func calcInputValueAge(tx *wire.MsgTx, utxoSet blockdag.UTXOSet, nextBlockHeight
 		// Don't attempt to accumulate the total input age if the
 		// referenced transaction output doesn't exist.
 		entry, ok := utxoSet.Get(txIn.PreviousOutPoint)
-		if ok && !entry.IsSpent() {
+		if ok {
 			// Inputs with dependencies currently in the mempool
 			// have their block height set to a special constant.
 			// Their input age should computed as zero since their

netsync/manager.go

@@ -879,7 +879,7 @@ func (sm *SyncManager) haveInventory(invVect *wire.InvVect) (bool, error) {
 			if !ok {
 				return false, nil
 			}
-			if entry != nil && !entry.IsSpent() {
+			if entry != nil {
 				return true, nil
 			}
 		}

server/rpc/rpcserver.go

@@ -2569,7 +2569,7 @@ func handleGetTxOut(s *Server, cmd interface{}, closeChan <-chan struct{}) (inte
 		// transaction already in the main chain.  Mined transactions
 		// that are spent by a mempool transaction are not affected by
 		// this.
-		if entry == nil || entry.IsSpent() {
+		if entry == nil {
 			return nil, nil
 		}