Add support for decoderawtransaction RPC command.

Since the decoderawtransaction result makes use of the same vin and vout
lists, this commit also factors the logic for those out into separate
functions.

rpcserver.go

@@ -653,7 +653,7 @@ func handleAskWallet(s *rpcServer, cmd btcjson.Cmd,
 	return nil, btcjson.ErrNoWallet
 }
 
-// handleDecodeRawTransaction handles decoderawtransaction commands.
+// handleAddNode handles addnode commands.
 func handleAddNode(s *rpcServer, cmd btcjson.Cmd,
 	walletNotification chan []byte) (interface{}, error) {
 	c := cmd.(*btcjson.AddNodeCmd)
@@ -698,11 +698,98 @@ func handleDebugLevel(s *rpcServer, cmd btcjson.Cmd,
 	return "Done.", nil
 }
 
+// createVinList returns a slice of JSON objects for the inputs of the passed
+// transaction.
+func createVinList(mtx *btcwire.MsgTx) []btcjson.Vin {
+	tx := btcutil.NewTx(mtx)
+	vinList := make([]btcjson.Vin, len(mtx.TxIn))
+	for i, v := range mtx.TxIn {
+		if btcchain.IsCoinBase(tx) {
+			vinList[i].Coinbase = hex.EncodeToString(v.SignatureScript)
+		} else {
+			vinList[i].Txid = v.PreviousOutpoint.Hash.String()
+			vinList[i].Vout = int(v.PreviousOutpoint.Index)
+
+			disbuf, _ := btcscript.DisasmString(v.SignatureScript)
+			vinList[i].ScriptSig = new(btcjson.ScriptSig)
+			vinList[i].ScriptSig.Asm = disbuf
+			vinList[i].ScriptSig.Hex = hex.EncodeToString(v.SignatureScript)
+		}
+		vinList[i].Sequence = v.Sequence
+	}
+
+	return vinList
+}
+
+// createVoutList returns a slice of JSON objects for the outputs of the passed
+// transaction.
+func createVoutList(mtx *btcwire.MsgTx, net btcwire.BitcoinNet) []btcjson.Vout {
+	voutList := make([]btcjson.Vout, len(mtx.TxOut))
+	for i, v := range mtx.TxOut {
+		voutList[i].N = i
+		voutList[i].Value = float64(v.Value) / float64(btcutil.SatoshiPerBitcoin)
+
+		_, addrhash, err := btcscript.ScriptToAddrHash(v.PkScript)
+		if err != nil {
+			txSha, _ := mtx.TxSha()
+			// TODO: set and return error?
+			rpcsLog.Errorf("Error getting address hash for %v: %v",
+				txSha, err)
+		}
+		if addr, err := btcutil.EncodeAddress(addrhash, net); err == nil {
+			// TODO: set and return error?
+			addrList := make([]string, 1)
+			addrList[0] = addr
+			voutList[i].ScriptPubKey.Addresses = addrList
+		}
+
+		disbuf, _ := btcscript.DisasmString(v.PkScript)
+		voutList[i].ScriptPubKey.Asm = disbuf
+		voutList[i].ScriptPubKey.Hex = hex.EncodeToString(v.PkScript)
+		voutList[i].ScriptPubKey.ReqSigs = strings.Count(disbuf, "OP_CHECKSIG")
+		voutList[i].ScriptPubKey.Type = btcscript.GetScriptClass(v.PkScript).String()
+	}
+
+	return voutList
+}
+
 // handleDecodeRawTransaction handles decoderawtransaction commands.
 func handleDecodeRawTransaction(s *rpcServer, cmd btcjson.Cmd,
 	walletNotification chan []byte) (interface{}, error) {
-	// TODO: use c.HexTx and fill result with info.
+	c := cmd.(*btcjson.DecodeRawTransactionCmd)
-	return btcjson.TxRawDecodeResult{}, nil
+
+	// Deserialize the transaction.
+	hexStr := c.HexTx
+	if len(hexStr)%2 != 0 {
+		hexStr = "0" + hexStr
+	}
+	serializedTx, err := hex.DecodeString(hexStr)
+	if err != nil {
+		return nil, btcjson.Error{
+			Code: btcjson.ErrInvalidParameter.Code,
+			Message: fmt.Sprintf("argument must be hexadecimal "+
+				"string (not %q)", hexStr),
+		}
+	}
+	var mtx btcwire.MsgTx
+	err = mtx.Deserialize(bytes.NewBuffer(serializedTx))
+	if err != nil {
+		return nil, btcjson.Error{
+			Code:    btcjson.ErrDeserialization.Code,
+			Message: "TX decode failed",
+		}
+	}
+	txSha, _ := mtx.TxSha()
+
+	// Create and return the result.
+	txReply := btcjson.TxRawDecodeResult{
+		Txid:     txSha.String(),
+		Version:  mtx.Version,
+		Locktime: mtx.LockTime,
+		Vin:      createVinList(&mtx),
+		Vout:     createVoutList(&mtx, s.server.btcnet),
+	}
+	return txReply, nil
 }
 
 // handleGetBestBlockHash implements the getbestblockhash command.
@@ -1015,57 +1102,16 @@ func handleGetRawTransaction(s *rpcServer, cmd btcjson.Cmd, walletNotification c
 // createTxRawResult converts the passed transaction and associated parameters
 // to a raw transaction JSON object.
 func createTxRawResult(net btcwire.BitcoinNet, txSha string, mtx *btcwire.MsgTx, blk *btcutil.Block, maxidx int64, blksha *btcwire.ShaHash) (*btcjson.TxRawResult, *btcjson.Error) {
-	tx := btcutil.NewTx(mtx)
 	mtxHex, err := messageToHex(mtx)
 	if err != nil {
 		return nil, err
 	}
 
-	vinList := make([]btcjson.Vin, len(mtx.TxIn))
-	for i, v := range mtx.TxIn {
-		if btcchain.IsCoinBase(tx) {
-			vinList[i].Coinbase = hex.EncodeToString(v.SignatureScript)
-		} else {
-			vinList[i].Txid = v.PreviousOutpoint.Hash.String()
-			vinList[i].Vout = int(uint32(v.PreviousOutpoint.Index))
-
-			disbuf, _ := btcscript.DisasmString(v.SignatureScript)
-			vinList[i].ScriptSig = new(btcjson.ScriptSig)
-			vinList[i].ScriptSig.Asm = disbuf
-			vinList[i].ScriptSig.Hex = hex.EncodeToString(v.SignatureScript)
-		}
-		vinList[i].Sequence = v.Sequence
-	}
-
-	voutList := make([]btcjson.Vout, len(mtx.TxOut))
-	for i, v := range mtx.TxOut {
-		voutList[i].N = i
-		voutList[i].Value = float64(v.Value) / float64(btcutil.SatoshiPerBitcoin)
-
-		_, addrhash, err := btcscript.ScriptToAddrHash(v.PkScript)
-		if err != nil {
-			// TODO: set and return error?
-			rpcsLog.Errorf("Error getting address hash for %v: %v", txSha, err)
-		}
-		if addr, err := btcutil.EncodeAddress(addrhash, net); err == nil {
-			// TODO: set and return error?
-			addrList := make([]string, 1)
-			addrList[0] = addr
-			voutList[i].ScriptPubKey.Addresses = addrList
-		}
-
-		disbuf, _ := btcscript.DisasmString(v.PkScript)
-		voutList[i].ScriptPubKey.Asm = disbuf
-		voutList[i].ScriptPubKey.Hex = hex.EncodeToString(v.PkScript)
-		voutList[i].ScriptPubKey.ReqSigs = strings.Count(disbuf, "OP_CHECKSIG")
-		voutList[i].ScriptPubKey.Type = btcscript.GetScriptClass(v.PkScript).String()
-	}
-
 	txReply := &btcjson.TxRawResult{
 		Hex:      mtxHex,
 		Txid:     txSha,
-		Vout:     voutList,
+		Vout:     createVoutList(mtx, net),
-		Vin:      vinList,
+		Vin:      createVinList(mtx),
 		Version:  mtx.Version,
 		LockTime: mtx.LockTime,
 	}