From f93bb35c021daa25bb4a61dee3dd5b73311f2c49 Mon Sep 17 00:00:00 2001
From: Ethan Buchman <ethan@coinculture.info>
Date: Sat, 21 Mar 2015 02:44:20 -0700
Subject: [PATCH] rpc: return tx hash, creates contract, contract addr in
 broadcast (required some helper functions). Closes #30

---
 merkle/simple_tree.go | 17 +++++++++++------
 rpc/mempool.go        | 19 ++++++++++++++++++-
 state/vm_app_state.go | 16 ++++++++++++----
 3 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/merkle/simple_tree.go b/merkle/simple_tree.go
index f31e36e5..bdc9164d 100644
--- a/merkle/simple_tree.go
+++ b/merkle/simple_tree.go
@@ -61,16 +61,21 @@ func HashFromHashes(hashes [][]byte) []byte {
 func HashFromBinaries(items []interface{}) []byte {
 	hashes := [][]byte{}
 	for _, item := range items {
-		hasher, n, err := sha256.New(), new(int64), new(error)
-		binary.WriteBinary(item, hasher, n, err)
-		if *err != nil {
-			panic(err)
-		}
-		hashes = append(hashes, hasher.Sum(nil))
+		hashes = append(hashes, HashFromBinary(item))
 	}
 	return HashFromHashes(hashes)
 }
 
+// General Convenience
+func HashFromBinary(item interface{}) []byte {
+	hasher, n, err := sha256.New(), new(int64), new(error)
+	binary.WriteBinary(item, hasher, n, err)
+	if *err != nil {
+		panic(err)
+	}
+	return hasher.Sum(nil)
+}
+
 // Convenience for HashFromHashes.
 func HashFromHashables(items []Hashable) []byte {
 	hashes := [][]byte{}
diff --git a/rpc/mempool.go b/rpc/mempool.go
index d047dbe5..0296ee69 100644
--- a/rpc/mempool.go
+++ b/rpc/mempool.go
@@ -6,6 +6,8 @@ import (
 	"github.com/tendermint/tendermint/binary"
 	blk "github.com/tendermint/tendermint/block"
 	. "github.com/tendermint/tendermint/common"
+	"github.com/tendermint/tendermint/merkle"
+	"github.com/tendermint/tendermint/state"
 )
 
 func BroadcastTxHandler(w http.ResponseWriter, r *http.Request) {
@@ -24,7 +26,22 @@ func BroadcastTxHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	WriteAPIResponse(w, API_OK, "")
+	txHash := merkle.HashFromBinary(tx)
+	var createsContract bool
+	var contractAddr []byte
+
+	if callTx, ok := tx.(*blk.CallTx); ok {
+		if callTx.Address == nil {
+			createsContract = true
+			contractAddr = state.NewContractAddress(callTx.Input.Address, uint64(callTx.Input.Sequence))
+		}
+	}
+
+	WriteAPIResponse(w, API_OK, struct {
+		TxHash          []byte
+		CreatesContract bool
+		ContractAddr    []byte
+	}{txHash, createsContract, contractAddr})
 	return
 }
 
diff --git a/state/vm_app_state.go b/state/vm_app_state.go
index ef696c96..643f30f8 100644
--- a/state/vm_app_state.go
+++ b/state/vm_app_state.go
@@ -113,10 +113,8 @@ func (vas *VMAppState) CreateAccount(creator *vm.Account) (*vm.Account, error) {
 	// Generate an address
 	nonce := creator.Nonce
 	creator.Nonce += 1
-	temp := make([]byte, 32+8)
-	copy(temp, creator.Address[:])
-	vm.PutUint64(temp[32:], nonce)
-	addr := vm.RightPadWord(sha3.Sha3(temp)[:20])
+
+	addr := vm.RightPadWord(NewContractAddress(creator.Address[:], nonce))
 
 	// Create account from address.
 	account, deleted := unpack(vas.accounts[addr.String()])
@@ -238,3 +236,13 @@ func (vas *VMAppState) Sync() {
 func (vas *VMAppState) AddLog(log *vm.Log) {
 	vas.logs = append(vas.logs, log)
 }
+
+//-----------------------------------------------------------------------------
+
+// Convenience function to return address of new contract
+func NewContractAddress(caller []byte, nonce uint64) []byte {
+	temp := make([]byte, 32+8)
+	copy(temp, caller)
+	vm.PutUint64(temp[32:], nonce)
+	return sha3.Sha3(temp)[:20]
+}