From a2ccf4f5264916350cc89128fe1356c8c89c5c82 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Fri, 26 Jan 2018 13:07:48 +0100
Subject: [PATCH] ethapi: refactor to minimize duplicate code

---
 internal/ethapi/api.go | 68 ++++++++++++++++--------------------------
 1 file changed, 25 insertions(+), 43 deletions(-)

diff --git a/internal/ethapi/api.go b/internal/ethapi/api.go
index 34de5d0770..c5dd0f2547 100644
--- a/internal/ethapi/api.go
+++ b/internal/ethapi/api.go
@@ -333,28 +333,19 @@ func (s *PrivateAccountAPI) LockAccount(addr common.Address) bool {
 	return fetchKeystore(s.am).Lock(addr) == nil
 }
 
-// SendTransaction will create a transaction from the given arguments and
-// tries to sign it with the key associated with args.To. If the given passwd isn't
-// able to decrypt the key it fails.
-func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
+// signTransactions sets defaults and signs the given transation
+// NOTE: the caller needs to ensure that the nonceLock is held, if applicable,
+// and release it after the transaction has been submitted to the tx pool
+func (s *PrivateAccountAPI) signTransaction(ctx context.Context, args SendTxArgs, passwd string) (*types.Transaction, error) {
 	// Look up the wallet containing the requested signer
 	account := accounts.Account{Address: args.From}
-
 	wallet, err := s.am.Find(account)
 	if err != nil {
-		return common.Hash{}, err
+		return nil, err
 	}
-
-	if args.Nonce == nil {
-		// Hold the addresse's mutex around signing to prevent concurrent assignment of
-		// the same nonce to multiple accounts.
-		s.nonceLock.LockAddr(args.From)
-		defer s.nonceLock.UnlockAddr(args.From)
-	}
-
 	// Set some sanity defaults and terminate on failure
 	if err := args.setDefaults(ctx, s.b); err != nil {
-		return common.Hash{}, err
+		return nil, err
 	}
 	// Assemble the transaction and sign with the wallet
 	tx := args.toTransaction()
@@ -363,7 +354,20 @@ func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs
 	if config := s.b.ChainConfig(); config.IsEIP155(s.b.CurrentBlock().Number()) {
 		chainID = config.ChainId
 	}
-	signed, err := wallet.SignTxWithPassphrase(account, passwd, tx, chainID)
+	return wallet.SignTxWithPassphrase(account, passwd, tx, chainID)
+}
+
+// SendTransaction will create a transaction from the given arguments and
+// tries to sign it with the key associated with args.To. If the given passwd isn't
+// able to decrypt the key it fails.
+func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs, passwd string) (common.Hash, error) {
+	if args.Nonce == nil {
+		// Hold the addresse's mutex around signing to prevent concurrent assignment of
+		// the same nonce to multiple accounts.
+		s.nonceLock.LockAddr(args.From)
+		defer s.nonceLock.UnlockAddr(args.From)
+	}
+	signed, err := s.signTransaction(ctx, args, passwd)
 	if err != nil {
 		return common.Hash{}, err
 	}
@@ -375,39 +379,17 @@ func (s *PrivateAccountAPI) SendTransaction(ctx context.Context, args SendTxArgs
 // able to decrypt the key it fails. The transaction is returned in RLP-form, not broadcast
 // to other nodes
 func (s *PrivateAccountAPI) SignTransaction(ctx context.Context, args SendTxArgs, passwd string) (*SignTransactionResult, error) {
-	// Look up the wallet containing the requested signer
-	account := accounts.Account{Address: args.From}
-
-	wallet, err := s.am.Find(account)
+	// No need to obtain the noncelock mutex, since we won't be sending this
+	// tx into the transaction pool, but right back to the user
+	signed, err := s.signTransaction(ctx, args, passwd)
 	if err != nil {
 		return nil, err
 	}
-	if args.Nonce == nil {
-		// Hold the addresse's mutex around signing to prevent concurrent assignment of
-		// the same nonce to multiple accounts.
-		s.nonceLock.LockAddr(args.From)
-		defer s.nonceLock.UnlockAddr(args.From)
-	}
-	// Set some sanity defaults and terminate on failure
-	if err := args.setDefaults(ctx, s.b); err != nil {
-		return nil, err
-	}
-	// Assemble the transaction and sign with the wallet
-	tx := args.toTransaction()
-
-	var chainID *big.Int
-	if config := s.b.ChainConfig(); config.IsEIP155(s.b.CurrentBlock().Number()) {
-		chainID = config.ChainId
-	}
-	tx, err = wallet.SignTxWithPassphrase(account, passwd, tx, chainID)
+	data, err := rlp.EncodeToBytes(signed)
 	if err != nil {
 		return nil, err
 	}
-	data, err := rlp.EncodeToBytes(tx)
-	if err != nil {
-		return nil, err
-	}
-	return &SignTransactionResult{data, tx}, nil
+	return &SignTransactionResult{data, signed}, nil
 }
 
 // signHash is a helper function that calculates a hash for the given message that can be