From e98b53bbef8cdbeed54546c75d856d53810e424c Mon Sep 17 00:00:00 2001
From: obscuren <geffobscura@gmail.com>
Date: Tue, 25 Feb 2014 11:22:27 +0100
Subject: [PATCH] WIP Observing pattern

---
 ethchain/transaction_pool.go | 41 +++++++++++++++++++++++++++++-------
 1 file changed, 33 insertions(+), 8 deletions(-)

diff --git a/ethchain/transaction_pool.go b/ethchain/transaction_pool.go
index 1278cc4dc7..cd09bf02ed 100644
--- a/ethchain/transaction_pool.go
+++ b/ethchain/transaction_pool.go
@@ -17,6 +17,17 @@ const (
 )
 
 type TxPoolHook chan *Transaction
+type TxMsgTy byte
+
+const (
+	TxPre = iota
+	TxPost
+)
+
+type TxMsg struct {
+	Tx   *Transaction
+	Type TxMsgTy
+}
 
 func FindTx(pool *list.List, finder func(*Transaction, *list.Element) bool) *Transaction {
 	for e := pool.Front(); e != nil; e = e.Next() {
@@ -59,6 +70,8 @@ type TxPool struct {
 	BlockManager *BlockManager
 
 	SecondaryProcessor TxProcessor
+
+	subscribers []chan TxMsg
 }
 
 func NewTxPool() *TxPool {
@@ -73,21 +86,17 @@ func NewTxPool() *TxPool {
 
 // Blocking function. Don't use directly. Use QueueTransaction instead
 func (pool *TxPool) addTransaction(tx *Transaction) {
-	log.Println("Adding tx to pool")
 	pool.mutex.Lock()
 	pool.pool.PushBack(tx)
 	pool.mutex.Unlock()
 
 	// Broadcast the transaction to the rest of the peers
 	pool.Speaker.Broadcast(ethwire.MsgTxTy, []interface{}{tx.RlpData()})
-	log.Println("broadcasting it")
 }
 
 // Process transaction validates the Tx and processes funds from the
 // sender to the recipient.
 func (pool *TxPool) ProcessTransaction(tx *Transaction, block *Block) (err error) {
-	log.Printf("[TXPL] Processing Tx %x\n", tx.Hash())
-
 	defer func() {
 		if r := recover(); r != nil {
 			log.Println(r)
@@ -132,6 +141,11 @@ func (pool *TxPool) ProcessTransaction(tx *Transaction, block *Block) (err error
 
 	block.UpdateAddr(tx.Sender(), sender)
 
+	log.Printf("[TXPL] Processed Tx %x\n", tx.Hash())
+
+	// Notify the subscribers
+	pool.notifySubscribers(TxPost, tx)
+
 	return
 }
 
@@ -145,7 +159,8 @@ func (pool *TxPool) ValidateTransaction(tx *Transaction) error {
 	}
 
 	// Get the sender
-	sender := block.GetAddr(tx.Sender())
+	accountState := pool.BlockManager.GetAddrState(tx.Sender())
+	sender := accountState.Account
 
 	totAmount := new(big.Int).Add(tx.Value, new(big.Int).Mul(TxFee, TxFeeRat))
 	// Make sure there's enough in the sender's account. Having insufficient
@@ -185,9 +200,8 @@ out:
 				// doesn't matter since this is a goroutine
 				pool.addTransaction(tx)
 
-				if pool.SecondaryProcessor != nil {
-					pool.SecondaryProcessor.ProcessTransaction(tx)
-				}
+				// Notify the subscribers
+				pool.notifySubscribers(TxPre, tx)
 			}
 		case <-pool.quit:
 			break out
@@ -231,3 +245,14 @@ func (pool *TxPool) Stop() {
 
 	pool.Flush()
 }
+
+func (pool *TxPool) Subscribe(channel chan TxMsg) {
+	pool.subscribers = append(pool.subscribers, channel)
+}
+
+func (pool *TxPool) notifySubscribers(ty TxMsgTy, tx *Transaction) {
+	msg := TxMsg{Type: ty, Tx: tx}
+	for _, subscriber := range pool.subscribers {
+		subscriber <- msg
+	}
+}