Get head block number

- Allows us to refuse to sync past current head
- Creates the opportunity to add a flag for syncing all blocks

pkg/datastore/ethereum/database.go

@@ -13,6 +13,7 @@ type Database interface {
 	GetBlock(hash []byte, blockNumber int64) *types.Block
 	GetBlockHash(blockNumber int64) []byte
 	GetBlockReceipts(blockHash []byte, blockNumber int64) types.Receipts
+	GetHeadBlockNumber() int64
 }
 
 func CreateDatabase(config DatabaseConfig) (Database, error) {

pkg/datastore/ethereum/level/database.go

@@ -32,3 +32,9 @@ func (l LevelDatabase) GetBlockReceipts(blockHash []byte, blockNumber int64) typ
 	h := common.BytesToHash(blockHash)
 	return l.reader.GetBlockReceipts(h, n)
 }
+
+func (l LevelDatabase) GetHeadBlockNumber() int64 {
+	h := l.reader.GetHeadBlockHash()
+	n := l.reader.GetBlockNumber(h)
+	return int64(n)
+}

pkg/datastore/ethereum/level/database_reader.go

@@ -8,26 +8,36 @@ import (
 
 type Reader interface {
 	GetBlock(hash common.Hash, number uint64) *types.Block
+	GetBlockNumber(hash common.Hash) uint64
 	GetBlockReceipts(hash common.Hash, number uint64) types.Receipts
 	GetCanonicalHash(number uint64) common.Hash
+	GetHeadBlockHash() common.Hash
 }
 
 type LevelDatabaseReader struct {
-	core.DatabaseReader
+	reader core.DatabaseReader
 }
 
 func NewLevelDatabaseReader(reader core.DatabaseReader) *LevelDatabaseReader {
-	return &LevelDatabaseReader{DatabaseReader: reader}
+	return &LevelDatabaseReader{reader: reader}
 }
 
 func (ldbr *LevelDatabaseReader) GetBlock(hash common.Hash, number uint64) *types.Block {
-	return core.GetBlock(ldbr.DatabaseReader, hash, number)
+	return core.GetBlock(ldbr.reader, hash, number)
+}
+
+func (ldbr *LevelDatabaseReader) GetBlockNumber(hash common.Hash) uint64 {
+	return core.GetBlockNumber(ldbr.reader, hash)
 }
 
 func (ldbr *LevelDatabaseReader) GetBlockReceipts(hash common.Hash, number uint64) types.Receipts {
-	return core.GetBlockReceipts(ldbr.DatabaseReader, hash, number)
+	return core.GetBlockReceipts(ldbr.reader, hash, number)
 }
 
 func (ldbr *LevelDatabaseReader) GetCanonicalHash(number uint64) common.Hash {
-	return core.GetCanonicalHash(ldbr.DatabaseReader, number)
+	return core.GetCanonicalHash(ldbr.reader, number)
+}
+
+func (ldbr *LevelDatabaseReader) GetHeadBlockHash() common.Hash {
+	return core.GetHeadBlockHash(ldbr.reader)
 }

pkg/datastore/ethereum/level/database_test.go

@@ -3,24 +3,12 @@ package level_test
 import (
 	"github.com/ethereum/go-ethereum/common"
 	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
 	"github.com/vulcanize/vulcanizedb/pkg/datastore/ethereum/level"
 	"github.com/vulcanize/vulcanizedb/pkg/fakes"
 )
 
 var _ = Describe("Level database", func() {
-	Describe("Getting a block hash", func() {
-		It("converts block number to uint64 to fetch hash from reader", func() {
-			mockReader := fakes.NewMockLevelDatabaseReader()
-			ldb := level.NewLevelDatabase(mockReader)
-			blockNumber := int64(12345)
-
-			ldb.GetBlockHash(blockNumber)
-
-			expectedBlockNumber := uint64(blockNumber)
-			mockReader.AssertGetCanonicalHashCalledWith(expectedBlockNumber)
-		})
-	})
-
 	Describe("Getting a block", func() {
 		It("converts block number to uint64 and hash to common.Hash to fetch block from reader", func() {
 			mockReader := fakes.NewMockLevelDatabaseReader()
@@ -36,6 +24,19 @@ var _ = Describe("Level database", func() {
 		})
 	})
 
+	Describe("Getting a block hash", func() {
+		It("converts block number to uint64 to fetch hash from reader", func() {
+			mockReader := fakes.NewMockLevelDatabaseReader()
+			ldb := level.NewLevelDatabase(mockReader)
+			blockNumber := int64(12345)
+
+			ldb.GetBlockHash(blockNumber)
+
+			expectedBlockNumber := uint64(blockNumber)
+			mockReader.AssertGetCanonicalHashCalledWith(expectedBlockNumber)
+		})
+	})
+
 	Describe("Getting a block's receipts", func() {
 		It("converts block number to uint64 and hash to common.Hash to fetch receipts from reader", func() {
 			mockReader := fakes.NewMockLevelDatabaseReader()
@@ -50,4 +51,21 @@ var _ = Describe("Level database", func() {
 			mockReader.AssertGetBlockReceiptsCalledWith(expectedBlockHash, expectedBlockNumber)
 		})
 	})
+
+	Describe("Getting the latest block number", func() {
+		It("invokes the database reader to get the latest block number by hash and converts result to int64", func() {
+			mockReader := fakes.NewMockLevelDatabaseReader()
+			fakeHash := common.BytesToHash([]byte{1, 2, 3, 4, 5})
+			mockReader.SetHeadBlockHashReturnHash(fakeHash)
+			fakeBlockNumber := uint64(123456789)
+			mockReader.SetReturnBlockNumber(fakeBlockNumber)
+			ldb := level.NewLevelDatabase(mockReader)
+
+			result := ldb.GetHeadBlockNumber()
+
+			mockReader.AssertGetHeadBlockHashCalled()
+			mockReader.AssertGetBlockNumberCalledWith(fakeHash)
+			Expect(result).To(Equal(int64(fakeBlockNumber)))
+		})
+	})
 })