From a31c7e9cedc42cd049b10f8eaea7602732c53bc2 Mon Sep 17 00:00:00 2001
From: Ian Norden <iannordenn@gmail.com>
Date: Mon, 15 Apr 2019 11:28:55 -0500
Subject: [PATCH] payload converter - interface for converting state diff
 payload into payload for ipld publishing

---
 pkg/ipfs/payload_converter.go | 110 ++++++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 pkg/ipfs/payload_converter.go

diff --git a/pkg/ipfs/payload_converter.go b/pkg/ipfs/payload_converter.go
new file mode 100644
index 00000000..24327c42
--- /dev/null
+++ b/pkg/ipfs/payload_converter.go
@@ -0,0 +1,110 @@
+// VulcanizeDB
+// Copyright © 2019 Vulcanize
+
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package ipfs
+
+import (
+	"context"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/statediff"
+
+	"github.com/vulcanize/vulcanizedb/pkg/core"
+)
+
+type Converter interface {
+	Convert(payload statediff.Payload) (*IPLDPayload, error)
+}
+
+type PayloadConverter struct {
+	client core.EthClient
+}
+
+type IPLDPayload struct {
+	HeaderRLP  []byte
+	BlockNumber *big.Int
+	BlockHash   common.Hash
+	BlockBody  *types.Body
+	Receipts   types.Receipts
+	StateLeafs  map[common.Hash][]byte
+	StorageLeafs map[common.Hash]map[common.Hash][]byte
+}
+
+func NewPayloadConverter(client core.EthClient) *PayloadConverter {
+	return &PayloadConverter{
+		client: client,
+	}
+}
+
+func (pc *PayloadConverter) Convert(payload statediff.Payload) (*IPLDPayload, error) {
+	// Unpack block rlp to access fields
+	block := new(types.Block)
+	err := rlp.DecodeBytes(payload.BlockRlp, block)
+	header := block.Header()
+	headerRlp, err := rlp.EncodeToBytes(header)
+	if err != nil {
+		return nil, err
+	}
+	convertedPayload := &IPLDPayload{
+		BlockHash: block.Hash(),
+		BlockNumber: block.Number(),
+		HeaderRLP: headerRlp,
+		BlockBody: block.Body(),
+		Receipts:  make(types.Receipts, 0),
+		StateLeafs: make(map[common.Hash][]byte),
+		StorageLeafs: make(map[common.Hash]map[common.Hash][]byte),
+	}
+	for _, trx := range block.Transactions() {
+		gethReceipt, err := pc.client.TransactionReceipt(context.Background(), trx.Hash())
+		if err != nil {
+			return nil, err
+		}
+		convertedPayload.Receipts = append(convertedPayload.Receipts, gethReceipt)
+	}
+
+	// Unpack state diff rlp to access fields
+	stateDiff := new(statediff.StateDiff)
+	err = rlp.DecodeBytes(payload.StateDiffRlp, stateDiff)
+	if err != nil {
+		return nil, err
+	}
+	for addr, createdAccount := range stateDiff.CreatedAccounts {
+		convertedPayload.StateLeafs[addr] = createdAccount.Value
+		convertedPayload.StorageLeafs[addr] = make(map[common.Hash][]byte)
+		for _, storageDiff := range createdAccount.Storage {
+			convertedPayload.StorageLeafs[addr][common.BytesToHash(storageDiff.Key)] = storageDiff.Value
+		}
+	}
+	for addr, deletedAccount := range stateDiff.DeletedAccounts {
+		convertedPayload.StateLeafs[addr] = deletedAccount.Value
+		convertedPayload.StorageLeafs[addr] = make(map[common.Hash][]byte)
+		for _, storageDiff := range deletedAccount.Storage {
+			convertedPayload.StorageLeafs[addr][common.BytesToHash(storageDiff.Key)] = storageDiff.Value
+		}
+	}
+	for addr, updatedAccount := range stateDiff.UpdatedAccounts {
+		convertedPayload.StateLeafs[addr] = updatedAccount.Value
+		convertedPayload.StorageLeafs[addr] = make(map[common.Hash][]byte)
+		for _, storageDiff := range updatedAccount.Storage {
+			convertedPayload.StorageLeafs[addr][common.BytesToHash(storageDiff.Key)] = storageDiff.Value
+		}
+	}
+	return convertedPayload, nil
+}
+