From 2cd62d00799f0f5aa4ac20c4d04d641922329513 Mon Sep 17 00:00:00 2001
From: ChronosX88 <chronosx88@gmail.com>
Date: Fri, 14 May 2021 23:32:49 +0300
Subject: [PATCH] Implement basic blockpool

---
 go.mod            |   1 +
 go.sum            |   2 +
 pool/blockpool.go | 137 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 140 insertions(+)
 create mode 100644 pool/blockpool.go

diff --git a/go.mod b/go.mod
index a677663..a5e902f 100644
--- a/go.mod
+++ b/go.mod
@@ -33,6 +33,7 @@ require (
 	github.com/jmoiron/sqlx v1.2.0
 	github.com/karalabe/usb v0.0.0-20191104083709-911d15fe12a9 // indirect
 	github.com/klauspost/cpuid/v2 v2.0.6 // indirect
+	github.com/ledgerwatch/lmdb-go v1.17.8 // indirect
 	github.com/libp2p/go-libp2p v0.12.0
 	github.com/libp2p/go-libp2p-core v0.7.0
 	github.com/libp2p/go-libp2p-pubsub v0.4.2-0.20210212194758-6c1addf493eb
diff --git a/go.sum b/go.sum
index b86294b..985b752 100644
--- a/go.sum
+++ b/go.sum
@@ -909,6 +909,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
 github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
+github.com/ledgerwatch/lmdb-go v1.17.8 h1:IQUVJ2MYIfSsrhz+o+QbugUqRQuqTXodt8pE6cuvQVg=
+github.com/ledgerwatch/lmdb-go v1.17.8/go.mod h1:NKRpCxksoTQPyxsUcBiVOe0135uqnJsnf6cElxmOL0o=
 github.com/leodido/go-urn v1.2.0 h1:hpXL4XnriNwQ/ABnpepYM/1vCLWNDfUNts8dX3xTG6Y=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/lib/pq v1.0.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
diff --git a/pool/blockpool.go b/pool/blockpool.go
new file mode 100644
index 0000000..b2c8ba1
--- /dev/null
+++ b/pool/blockpool.go
@@ -0,0 +1,137 @@
+package pool
+
+import (
+	"encoding/hex"
+	"errors"
+
+	"github.com/Secured-Finance/dione/types"
+	"github.com/fxamacker/cbor/v2"
+	"github.com/ledgerwatch/lmdb-go/lmdb"
+)
+
+const (
+	DefaultBlockPrefix       = "block_"
+	DefaultBlockHeaderPrefix = "header_"
+)
+
+var (
+	ErrBlockNotFound = errors.New("block isn't found")
+)
+
+type BlockPool struct {
+	dbEnv *lmdb.Env
+	db    lmdb.DBI
+}
+
+func NewBlockPool(path string) (*BlockPool, error) {
+	pool := &BlockPool{}
+
+	// configure lmdb env
+	env, err := lmdb.NewEnv()
+	if err != nil {
+		return nil, err
+	}
+
+	err = env.SetMapSize(100 * 1024 * 1024 * 1024) // 100 GB
+	if err != nil {
+		return nil, err
+	}
+
+	err = env.Open(path, 0, 0664)
+	if err != nil {
+		return nil, err
+	}
+
+	pool.dbEnv = env
+
+	var dbi lmdb.DBI
+	err = env.Update(func(txn *lmdb.Txn) error {
+		dbi, err = txn.OpenDBI("blocks", lmdb.Create)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	pool.db = dbi
+
+	return pool, nil
+}
+
+func (bp *BlockPool) StoreBlock(block *types.Block) error {
+	return bp.dbEnv.Update(func(txn *lmdb.Txn) error {
+		data, err := cbor.Marshal(block)
+		if err != nil {
+			return err
+		}
+		headerData, err := cbor.Marshal(block.Header)
+		if err != nil {
+			return err
+		}
+		blockHash := hex.EncodeToString(block.Header.Hash)
+		err = txn.Put(bp.db, []byte(DefaultBlockPrefix+blockHash), data, 0)
+		if err != nil {
+			return err
+		}
+		err = txn.Put(bp.db, []byte(DefaultBlockHeaderPrefix+blockHash), headerData, 0) // store header separately for easy fetching
+		return err
+	})
+}
+
+func (bp *BlockPool) HasBlock(blockHash string) (bool, error) {
+	var blockExists bool
+	err := bp.dbEnv.View(func(txn *lmdb.Txn) error {
+		_, err := txn.Get(bp.db, []byte(DefaultBlockPrefix+blockHash)) // try to fetch block header
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				blockExists = false
+				return nil
+			}
+			return err
+		}
+		blockExists = true
+		return nil
+	})
+	if err != nil {
+		return false, err
+	}
+	return blockExists, nil
+}
+
+func (bp *BlockPool) FetchBlock(blockHash string) (*types.Block, error) {
+	var block types.Block
+	err := bp.dbEnv.View(func(txn *lmdb.Txn) error {
+		data, err := txn.Get(bp.db, []byte(DefaultBlockPrefix+blockHash))
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				return ErrBlockNotFound
+			}
+			return err
+		}
+		err = cbor.Unmarshal(data, &block)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &block, nil
+}
+
+func (bp *BlockPool) FetchBlockHeader(blockHash string) (*types.BlockHeader, error) {
+	var blockHeader types.BlockHeader
+	err := bp.dbEnv.View(func(txn *lmdb.Txn) error {
+		data, err := txn.Get(bp.db, []byte(DefaultBlockHeaderPrefix+blockHash))
+		if err != nil {
+			if lmdb.IsNotFound(err) {
+				return ErrBlockNotFound
+			}
+			return err
+		}
+		err = cbor.Unmarshal(data, &blockHeader)
+		return err
+	})
+	if err != nil {
+		return nil, err
+	}
+	return &blockHeader, nil
+}