From 63b5926e01fe38c16c248fca5f372064abca499d Mon Sep 17 00:00:00 2001
From: Tadge Dryja <tadge@lightning.network>
Date: Fri, 5 Feb 2016 01:59:40 -0800
Subject: [PATCH] add getalltxs, dup checks

Start of double spend detection for mempool and reorgs
---
 shell.go        | 18 ++++++++++++++++++
 uspv/txstore.go | 33 ++++++++++++++++++++++++++++++++-
 uspv/utxodb.go  | 27 +++++++++++++++++++++++++++
 3 files changed, 77 insertions(+), 1 deletion(-)

diff --git a/shell.go b/shell.go
index cf1def75..21dd499a 100644
--- a/shell.go
+++ b/shell.go
@@ -144,11 +144,29 @@ func Shellparse(cmdslice []string) error {
 		}
 		return nil
 	}
+	if cmd == "txs" {
+		err = Txs(args)
+		if err != nil {
+			fmt.Printf("txs error: %s\n", err)
+		}
+		return nil
+	}
 
 	fmt.Printf("Command not recognized. type help for command list.\n")
 	return nil
 }
 
+func Txs(args []string) error {
+	alltx, err := SCon.TS.GetAllTxs()
+	if err != nil {
+		return err
+	}
+	for i, tx := range alltx {
+		fmt.Printf("tx %d %s\n", i, uspv.TxToString(tx))
+	}
+	return nil
+}
+
 // Bal prints out your score.
 func Bal(args []string) error {
 	if SCon.TS == nil {
diff --git a/uspv/txstore.go b/uspv/txstore.go
index 6fde5fe8..b5596ef7 100644
--- a/uspv/txstore.go
+++ b/uspv/txstore.go
@@ -100,9 +100,40 @@ func (t *TxStore) GimmeFilter() (*bloom.Filter, error) {
 	return f, nil
 }
 
+// GetDoubleSpends takes a transaction and compares it with
+// all transactions in the db.  It returns a slice of all txids in the db
+// which are double spent by the received tx.
+func GetDoubleSpends(
+	argTx *wire.MsgTx, txs []*wire.MsgTx) ([]*wire.ShaHash, error) {
+
+	var dubs []*wire.ShaHash // slice of all double-spent txs
+	argTxid := argTx.TxSha()
+
+	for _, compTx := range txs {
+		compTxid := compTx.TxSha()
+		// check if entire tx is dup
+		if argTxid.IsEqual(&compTxid) {
+			return nil, fmt.Errorf("tx %s is dup", argTxid.String())
+		}
+		// not dup, iterate through inputs of argTx
+		for _, argIn := range argTx.TxIn {
+			// iterate through inputs of compTx
+			for _, compIn := range compTx.TxIn {
+				if OutPointsEqual(
+					argIn.PreviousOutPoint, compIn.PreviousOutPoint) {
+					// found double spend
+					dubs = append(dubs, &compTxid)
+					break // back to argIn loop
+				}
+			}
+		}
+	}
+	return dubs, nil
+}
+
 // TxToString prints out some info about a transaction. for testing / debugging
 func TxToString(tx *wire.MsgTx) string {
-	str := "\t\t\t - Tx - \n"
+	str := fmt.Sprintf("\t - Tx %s\n", tx.TxSha().String())
 	for i, in := range tx.TxIn {
 		str += fmt.Sprintf("Input %d: %s\n", i, in.PreviousOutPoint.String())
 		str += fmt.Sprintf("SigScript for input %d: %x\n", i, in.SignatureScript)
diff --git a/uspv/utxodb.go b/uspv/utxodb.go
index 26e5360a..8c08449a 100644
--- a/uspv/utxodb.go
+++ b/uspv/utxodb.go
@@ -248,6 +248,33 @@ func (ts *TxStore) GetTx(txid *wire.ShaHash) (*wire.MsgTx, error) {
 	return rtx, nil
 }
 
+// GetTx takes a txid and returns the transaction.  If we have it.
+func (ts *TxStore) GetAllTxs() ([]*wire.MsgTx, error) {
+	var rtxs []*wire.MsgTx
+
+	err := ts.StateDB.View(func(btx *bolt.Tx) error {
+		txns := btx.Bucket(BKTTxns)
+		if txns == nil {
+			return fmt.Errorf("no transactions in db")
+		}
+
+		return txns.ForEach(func(k, v []byte) error {
+			tx := wire.NewMsgTx()
+			buf := bytes.NewBuffer(v)
+			err := tx.Deserialize(buf)
+			if err != nil {
+				return err
+			}
+			rtxs = append(rtxs, tx)
+			return nil
+		})
+	})
+	if err != nil {
+		return nil, err
+	}
+	return rtxs, nil
+}
+
 // GetPendingInv returns an inv message containing all txs known to the
 // db which are at height 0 (not known to be confirmed).
 // This can be useful on startup or to rebroadcast unconfirmed txs.