From e6cf54a124f72f17a10e2ac2716bd47f24922e82 Mon Sep 17 00:00:00 2001
From: Ivan Kuznetsov <me@jeiwan.ru>
Date: Mon, 28 Aug 2017 16:16:45 +0700
Subject: [PATCH] Refactor NewBlockchain

---
 blockchain.db | Bin 32768 -> 32768 bytes
 blockchain.go |  47 +++++++++++++++++------------------------------
 main.go       |   4 ++--
 3 files changed, 19 insertions(+), 32 deletions(-)

diff --git a/blockchain.db b/blockchain.db
index f3f24abde6fae89fb4a4ef491047ec1bd402c7d4..090c32ce8f4764e27c0298725bbf74d4e9e09ced 100644
GIT binary patch
delta 661
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z|0c#io85Q4W8`&D%}XuLELL#J$xqH^QeYsUo$;Th7Xt(LQXcnnmaYDoZZ8T&RN^CK
z7GFDQqIY_-<bwl7qJ{T>c7!wSdN+BVqIfzX^Ardf#`sSuk0FPUs*Qn9csCgY2?*|H
zfB<er1_lKnvww23gNi)kA@NJgS3g^jE99Um|F-8SzsJW8nQc~KuYJ1SC-S@l1qx>t
oEKnw|bCgLV;6+9S1_EX>{)_iuAQYTKH8u$NePiHHo<#u$0ISO)!vFvP

delta 655
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zjJ)otd8x&j#R^V2`N`Q#3Je7FG5%vSVPIgtRdWCEq@c;ga`%#6Doksiesf37wn8zv
zUoBs~zfIEw8XhpY!HJ!z)@brPMe%e(W-1UekntbuCx#qCsx}5b;oW2qBp}$&00H-b
z6wpTuyC)|*sL(b<SS04k`giXxs417|<@xG!dHZeKkX;+P*jBF4y_|h>B`8EVv;H?R
n{@Lsf43z&4GHC?DkWqnwfSHW{nqmelDhRl3W8hDoMF9o?@z5bY

diff --git a/blockchain.go b/blockchain.go
index affba08..0aecb89 100644
--- a/blockchain.go
+++ b/blockchain.go
@@ -1,9 +1,7 @@
 package main
 
 import (
-	"fmt"
 	"log"
-	"os"
 
 	"github.com/boltdb/bolt"
 )
@@ -13,8 +11,7 @@ const blocksBucket = "blocks"
 
 // Blockchain keeps a sequence of Blocks
 type Blockchain struct {
-	blocks []*Block
-	tip    []byte
+	tip []byte
 }
 
 // BlockchainIterator is used to iterate over blockchain blocks
@@ -91,18 +88,18 @@ func (i *BlockchainIterator) Next() *Block {
 // NewBlockchain creates a new Blockchain with genesis Block
 func NewBlockchain() *Blockchain {
 	bc := Blockchain{}
+	db, err := bolt.Open(dbFile, 0600, nil)
+	if err != nil {
+		log.Panic(err)
+	}
+	defer db.Close()
 
-	if _, err := os.Stat(dbFile); os.IsNotExist(err) {
-		fmt.Println("Creating a new blockchain...")
-		db, err := bolt.Open(dbFile, 0600, nil)
-		if err != nil {
-			log.Panic(err)
-		}
-		defer db.Close()
+	err = db.Update(func(tx *bolt.Tx) error {
+		b := tx.Bucket([]byte(blocksBucket))
 
-		genesis := NewGenesisBlock()
+		if b == nil {
+			genesis := NewGenesisBlock()
 
-		err = db.Update(func(tx *bolt.Tx) error {
 			b, err := tx.CreateBucket([]byte(blocksBucket))
 			if err != nil {
 				log.Panic(err)
@@ -117,26 +114,16 @@ func NewBlockchain() *Blockchain {
 			if err != nil {
 				log.Panic(err)
 			}
-
-			return nil
-		})
-
-		bc.tip = genesis.Hash
-	} else {
-		// TODO: remove the duplication, check for the "l" key
-		db, err := bolt.Open(dbFile, 0600, nil)
-		if err != nil {
-			log.Panic(err)
-		}
-		defer db.Close()
-
-		err = db.View(func(tx *bolt.Tx) error {
-			b := tx.Bucket([]byte(blocksBucket))
+			bc.tip = genesis.Hash
+		} else {
 			tip := b.Get([]byte("l"))
 			bc.tip = tip
+		}
 
-			return nil
-		})
+		return nil
+	})
+	if err != nil {
+		log.Panic(err)
 	}
 
 	return &bc
diff --git a/main.go b/main.go
index dec9ab4..58fcacd 100644
--- a/main.go
+++ b/main.go
@@ -8,8 +8,8 @@ import (
 func main() {
 	bc := NewBlockchain()
 
-	// bc.AddBlock("Send 1 BTC to Ivan")
-	// bc.AddBlock("Send 2 more BTC to Ivan")
+	bc.AddBlock("Send 1 BTC to Ivan")
+	bc.AddBlock("Send 2 more BTC to Ivan")
 
 	bci := bc.Iterator()