These changes are a terrible, incredibly hacky solution to storing ou…

…r fetched headers, I will revise.

blockchain.go

@@ -37,13 +37,13 @@ func (bh *BlockHandle) BlockSha() (btcwire.ShaHash, error) {
 func (chain *BlockChain) Save(header *btcwire.BlockHeader) (*BlockHandle, error) {
 	parent, err := chain.Get(&header.PrevBlock)
 	if err != nil {
-		fmt.Errorf("No parent found for: %#v", header)
+		log.Fatal("No parent found for: %#v", header)
 		return nil, err
 	}
 	// save a string to store our 'real' block with
 	block_sha, err := header.BlockSha(btcwire.ProtocolVersion)
 	if err != nil {
-		fmt.Errorf("Something went wrong deriving the block hash for: %#v", header)
+		log.Fatal("Something went wrong deriving the block hash for: %#v", header)
 		return nil, err
 	}
 	bls_elems := []string{"blk", block_sha.String()}
@@ -89,20 +89,62 @@ func (chain *BlockChain) FindParent(bh *BlockHandle) (*BlockHandle, error) {
 }
 
 func InitializeBlockChain() (*BlockChain, error) {
-	bc := BlockChain{Last: btcwire.GenesisHash, ChainHead: btcwire.GenesisHash, Genesis: btcwire.GenesisHash}
+	gob.Register(btcwire.ShaHash{})
 	db, err := gocask.NewGocask("bitcoin")
-	bc.Database = db
-	if err != nil {
-		return nil, err
-	}
-
-	genesis := BlockHandle{Hash: btcwire.GenesisHash, Header: btcwire.GenesisBlock.Header}
-	var block_bytes bytes.Buffer
-	encoder := gob.NewEncoder(&block_bytes)
-	encoder.Encode(genesis)
-	err = bc.Database.Put(btcwire.GenesisHash.String(), block_bytes.Bytes())
-
-	return &bc, nil
+  chain_bytes, err := db.Get("chainhead")
+  if err == nil {
+    var bc BlockChain 
+    bc.Database = db
+    head_hash, err := btcwire.NewShaHash(chain_bytes)
+    if err != nil {
+      return nil, err
+    }
+    bc.Last = *head_hash
+    bc.ChainHead = *head_hash
+    chainhead_handle, err := bc.Get(head_hash)
+    if err != nil {
+      log.Fatal("Couldn't derive Chain Head")
+      return nil, nil
+    }
+
+    bc.ChainHeadDepth = chainhead_handle.Depth 
+    bc.Genesis = btcwire.GenesisHash
+    fmt.Printf("Loaded previous  blockchain with a depth of: %d\n", bc.ChainHeadDepth)
+    return &bc, nil
+  } else {
+    bc := BlockChain{Last: btcwire.GenesisHash, ChainHead: btcwire.GenesisHash, Genesis: btcwire.GenesisHash}
+    err = db.Put("chainhead", btcwire.GenesisHash.Bytes())
+    if err != nil {
+      return nil, err
+    }
+    bc.Database = db
+
+    // save a string to store our 'real' block with
+    block_sha, err := btcwire.GenesisBlock.Header.BlockSha(btcwire.ProtocolVersion)
+    if err != nil {
+      log.Fatal("Something went wrong deriving the genesis block hash")
+      return nil, err
+    }
+    bls_elems := []string{"blk", block_sha.String()}
+    block_lookup_string := strings.Join(bls_elems, "")
+    block := BlockHandle{Hash: block_sha,
+      Header: btcwire.GenesisBlock.Header,
+      Depth:  0, 
+      Block:  block_lookup_string}
+    var block_bytes bytes.Buffer
+    encoder := gob.NewEncoder(&block_bytes)
+    encoder.Encode(block)
+    err = db.Put(block_sha.String(), block_bytes.Bytes())
+    if err != nil {
+      log.Fatal("Couldn't save Genesis Block Header")
+      return nil, err
+    }
+
+    // genesis := BlockHandle{Hash: btcwire.GenesisHash, Header: btcwire.GenesisBlock.Header}
+    return &bc, nil
+
+  }
+  return nil, nil  
 }
 
 // create a block from a header we've read and add it to our blockchain
@@ -113,10 +155,30 @@ func (chain *BlockChain) InitializeBlock(header *btcwire.BlockHeader) (*BlockHan
 		return nil, err
 	}
 	// add a reference to our current chain head
-	if chain.ChainHeadDepth < block.Depth {
-		chain.ChainHead, _ = block.BlockSha()
-		chain.ChainHeadDepth = block.Depth
+  chain_head_bytes, err := chain.Database.Get("chainhead")
+  if err != nil {
+    return nil, err
+  }
+
+  chain_head_hash, err := btcwire.NewShaHash(chain_head_bytes)
+  if err != nil {
+    return nil, err
+  }
+
+  chain_head, err := chain.Get(chain_head_hash)
+  if err != nil {
+    return nil, err
+  }
+
+	if chain_head.Depth < block.Depth {
+    chain_head_sha, _ := block.BlockSha()
+    chain.ChainHead = chain_head_sha 
+    // we should defer this to only write when we're about to exit because of the
+    // append only nature of bitcask 
+    chain.Database.Put("chainhead", chain_head_sha.Bytes()) 
+    chain.ChainHeadDepth = block.Depth
 	}
+
 	return block, nil
 }