From 1793e7d21d88283719404b004b6d67ddf14ff491 Mon Sep 17 00:00:00 2001
From: Raul Jordan <rauljordan@college.harvard.edu>
Date: Thu, 3 May 2018 11:54:05 -0500
Subject: [PATCH] sharding: fetch body by chunk root

Former-commit-id: 5021890d223501bf163d6beae4e4e732673950d2 [formerly 92e89aed0c61909971cf9262cd3002bf2ae2328a]
Former-commit-id: 0fd4497f880213878965107de3f782b44c33f065
---
 sharding/db.go    |  8 ++++----
 sharding/shard.go | 21 +++++++++++++++------
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/sharding/db.go b/sharding/db.go
index 9e3889eeb..b016f7f8e 100644
--- a/sharding/db.go
+++ b/sharding/db.go
@@ -6,11 +6,11 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
-type shardBackend struct {
+type shardKV struct {
 	kv map[common.Hash][]byte
 }
 
-func (sb *shardBackend) Get(k common.Hash) ([]byte, error) {
+func (sb *shardKV) Get(k common.Hash) ([]byte, error) {
 	v := sb.kv[k]
 	if v == nil {
 		return nil, fmt.Errorf("Key Not Found")
@@ -18,12 +18,12 @@ func (sb *shardBackend) Get(k common.Hash) ([]byte, error) {
 	return v, nil
 }
 
-func (sb *shardBackend) Put(k common.Hash, v []byte) {
+func (sb *shardKV) Put(k common.Hash, v []byte) {
 	sb.kv[k] = v
 	return
 }
 
-func (sb *shardBackend) Delete(k common.Hash) {
+func (sb *shardKV) Delete(k common.Hash) {
 	delete(sb.kv, k)
 	return
 }
diff --git a/sharding/shard.go b/sharding/shard.go
index 38de4f9b7..2ecaf185b 100644
--- a/sharding/shard.go
+++ b/sharding/shard.go
@@ -10,7 +10,7 @@ import (
 
 // Shard base struct.
 type Shard struct {
-	shardDB *shardBackend
+	shardDB *shardKV
 	shardID *big.Int
 }
 
@@ -22,8 +22,8 @@ func (s *Shard) ValidateShardID(h *CollationHeader) error {
 	return nil
 }
 
-// SetHeader adds the collation header to shardDB
-func (s *Shard) SetHeader(h *CollationHeader) error {
+// SaveHeader adds the collation header to shardDB.
+func (s *Shard) SaveHeader(h *CollationHeader) error {
 	if err := s.ValidateShardID(h); err != nil {
 		return err
 	}
@@ -35,6 +35,15 @@ func (s *Shard) SetHeader(h *CollationHeader) error {
 	return nil
 }
 
+// SaveCollationBody adds the collation body to shardDB.
+func (s *Shard) SaveCollationBody(body []byte) error {
+	// TODO: dependent on blob serialization.
+	// chunkRoot := getChunkRoot(body) using the blob algorithm utils.
+	// s.shardDB.Put(chunkRoot, body)
+	// s.SetAvailability(chunkRoot, true)
+	return nil
+}
+
 // GetHeaderByHash of collation.
 func (s *Shard) GetHeaderByHash(hash common.Hash) (*CollationHeader, error) {
 	encoded, err := s.shardDB.Get(hash)
@@ -61,7 +70,7 @@ func (s *Shard) GetCollationByHash(hash common.Hash) (*Collation, error) {
 	return &Collation{header: header, body: body}, nil
 }
 
-// GetBodyByChunkRoot fetches a collation body
+// GetBodyByChunkRoot fetches a collation body.
 func (s *Shard) GetBodyByChunkRoot(chunkRoot common.Hash) ([]byte, error) {
 	body, err := s.shardDB.Get(chunkRoot)
 	if err != nil {
@@ -75,7 +84,7 @@ func (s *Shard) CheckAvailability(header *CollationHeader) bool {
 	return true
 }
 
-// SetUnavailable ensures to set a collation as unavailable in the shardDB.
-func (s *Shard) SetUnavailable(header *CollationHeader) error {
+// SetAvailability saves the availability of the chunk root in the shardDB.
+func (s *Shard) SetAvailability(chunkRoot *common.Hash) error {
 	return nil
 }