core, eth, ethapi, graphql, les, light, rpc: Support Block Number or …

…Hash on state-related RPCs.

* Support for EIP-1898.

core/blockchain.go

@@ -1704,6 +1704,11 @@ func (bc *BlockChain) HasHeader(hash common.Hash, number uint64) bool {
 	return bc.hc.HasHeader(hash, number)
 }
 
+// GetCanonicalHash returns the canonical hash for a given block number
+func (bc *BlockChain) GetCanonicalHash(number uint64) common.Hash {
+	return bc.hc.GetCanonicalHash(number)
+}
+
 // GetBlockHashesFromHash retrieves a number of block hashes starting at a given
 // hash, fetching towards the genesis block.
 func (bc *BlockChain) GetBlockHashesFromHash(hash common.Hash, max uint64) []common.Hash {

core/headerchain.go

@@ -439,6 +439,10 @@ func (hc *HeaderChain) GetHeaderByNumber(number uint64) *types.Header {
 	return hc.GetHeader(hash, number)
 }
 
+func (hc *HeaderChain) GetCanonicalHash(number uint64) common.Hash {
+	return rawdb.ReadCanonicalHash(hc.chainDb, number)
+}
+
 // CurrentHeader retrieves the current head header of the canonical chain. The
 // header is retrieved from the HeaderChain's internal cache.
 func (hc *HeaderChain) CurrentHeader() *types.Header {

eth/api_backend.go

@@ -18,6 +18,7 @@ package eth
 
 import (
 	"context"
+	"fmt"
 	"math/big"
 
 	"github.com/ethereum/go-ethereum/accounts"
@@ -70,6 +71,27 @@ func (b *EthAPIBackend) HeaderByNumber(ctx context.Context, blockNr rpc.BlockNum
 	return b.eth.blockchain.GetHeaderByNumber(uint64(blockNr)), nil
 }
 
+func (b *EthAPIBackend) HeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Header, error) {
+	if blockNr, ok := blockNrOrHash.Number(); ok {
+		return b.HeaderByNumber(ctx, blockNr)
+	}
+
+	if hash, ok := blockNrOrHash.Hash(); ok {
+		header := b.eth.blockchain.GetHeaderByHash(hash)
+		if header == nil {
+			return nil, fmt.Errorf("header for hash not found")
+		}
+
+		if blockNrOrHash.RequireCanonical && b.eth.blockchain.GetCanonicalHash(header.Number.Uint64()) != hash {
+			return nil, fmt.Errorf("hash is not currently canonical")
+		}
+
+		return header, nil
+	}
+
+	return nil, fmt.Errorf("specifier neither block nor hash")
+}
+
 func (b *EthAPIBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
 	return b.eth.blockchain.GetHeaderByHash(hash), nil
 }
@@ -87,6 +109,32 @@ func (b *EthAPIBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 	return b.eth.blockchain.GetBlockByNumber(uint64(blockNr)), nil
 }
 
+func (b *EthAPIBackend) BlockByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*types.Block, error) {
+	if blockNr, ok := blockNrOrHash.Number(); ok {
+		return b.BlockByNumber(ctx, blockNr)
+	}
+
+	if hash, ok := blockNrOrHash.Hash(); ok {
+		header := b.eth.blockchain.GetHeaderByHash(hash)
+		if header == nil {
+			return nil, fmt.Errorf("header for hash not found")
+		}
+
+		if blockNrOrHash.RequireCanonical && b.eth.blockchain.GetCanonicalHash(header.Number.Uint64()) != hash {
+			return nil, fmt.Errorf("hash is not currently canonical")
+		}
+
+		block := b.eth.blockchain.GetBlock(hash, header.Number.Uint64())
+		if block == nil {
+			return nil, fmt.Errorf("block not found with hash at expected number")
+		}
+
+		return block, nil
+	}
+
+	return nil, fmt.Errorf("specifier neither block nor hash")
+}
+
 func (b *EthAPIBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (*state.StateDB, *types.Header, error) {
 	// Pending state is only known by the miner
 	if blockNr == rpc.PendingBlockNumber {
@@ -102,6 +150,32 @@ func (b *EthAPIBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.
 	return stateDb, header, err
 }
 
+func (b *EthAPIBackend) StateAndHeaderByNumberOrHash(ctx context.Context, blockNrOrHash rpc.BlockNumberOrHash) (*state.StateDB, *types.Header, error) {
+	if blockNr, ok := blockNrOrHash.Number(); ok {
+		return b.StateAndHeaderByNumber(ctx, blockNr)
+	}
+
+	if hash, ok := blockNrOrHash.Hash(); ok {
+		header, err := b.HeaderByHash(ctx, hash)
+		if err != nil {
+			return nil, nil, err
+		}
+
+		if header == nil {
+			return nil, nil, fmt.Errorf("header for hash not found")
+		}
+
+		if blockNrOrHash.RequireCanonical && b.eth.blockchain.GetCanonicalHash(header.Number.Uint64()) != hash {
+			return nil, nil, fmt.Errorf("hash is not currently canonical")
+		}
+
+		stateDb, err := b.eth.BlockChain().StateAt(header.Root)
+		return stateDb, header, err
+	}
+
+	return nil, nil, fmt.Errorf("specifier neither block nor hash")
+}
+
 func (b *EthAPIBackend) GetBlock(ctx context.Context, hash common.Hash) (*types.Block, error) {
 	return b.eth.blockchain.GetBlockByHash(hash), nil
 }