core/state: access trie through Database interface, track errors (#14589)

With this commit, core/state's access to the underlying key/value database is
mediated through an interface. Database errors are tracked in StateDB and
returned by CommitTo or the new Error method.

Motivation for this change: We can remove the light client's duplicated copy of
core/state. The light client now supports node iteration, so tracing and storage
enumeration can work with the light client (not implemented in this commit).

6 files changed, 12 insertions, 37 deletions

diff --git a/eth/api.go b/eth/api.go
index 81570988c..0d90759b6 100644
--- a/eth/api.go
+++ b/eth/api.go
@@ -637,7 +637,7 @@ func (api *PrivateDebugAPI) StorageRangeAt(ctx context.Context, blockHash common
 	return storageRangeAt(st, keyStart, maxResult), nil
 }
 
-func storageRangeAt(st *trie.SecureTrie, start []byte, maxResult int) StorageRangeResult {
+func storageRangeAt(st state.Trie, start []byte, maxResult int) StorageRangeResult {
 	it := trie.NewIterator(st.NodeIterator(start))
 	result := StorageRangeResult{Storage: storageMap{}}
 	for i := 0; i < maxResult && it.Next(); i++ {
diff --git a/eth/api_backend.go b/eth/api_backend.go
index fe108d272..166b5084d 100644
--- a/eth/api_backend.go
+++ b/eth/api_backend.go
@@ -31,7 +31,6 @@ import (
 	"github.com/ethereum/go-ethereum/eth/gasprice"
 	"github.com/ethereum/go-ethereum/ethdb"
 	"github.com/ethereum/go-ethereum/event"
-	"github.com/ethereum/go-ethereum/internal/ethapi"
 	"github.com/ethereum/go-ethereum/params"
 	"github.com/ethereum/go-ethereum/rpc"
 )
@@ -81,11 +80,11 @@ func (b *EthApiBackend) BlockByNumber(ctx context.Context, blockNr rpc.BlockNumb
 	return b.eth.blockchain.GetBlockByNumber(uint64(blockNr)), nil
 }
 
-func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.BlockNumber) (ethapi.State, *types.Header, error) {
+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 {
 		block, state := b.eth.miner.Pending()
-		return EthApiState{state}, block.Header(), nil
+		return state, block.Header(), nil
 	}
 	// Otherwise resolve the block number and return its state
 	header, err := b.HeaderByNumber(ctx, blockNr)
@@ -93,7 +92,7 @@ func (b *EthApiBackend) StateAndHeaderByNumber(ctx context.Context, blockNr rpc.
 		return nil, nil, err
 	}
 	stateDb, err := b.eth.BlockChain().StateAt(header.Root)
-	return EthApiState{stateDb}, header, err
+	return stateDb, header, err
 }
 
 func (b *EthApiBackend) GetBlock(ctx context.Context, blockHash common.Hash) (*types.Block, error) {
@@ -108,14 +107,12 @@ func (b *EthApiBackend) GetTd(blockHash common.Hash) *big.Int {
 	return b.eth.blockchain.GetTdByHash(blockHash)
 }
 
-func (b *EthApiBackend) GetEVM(ctx context.Context, msg core.Message, state ethapi.State, header *types.Header, vmCfg vm.Config) (*vm.EVM, func() error, error) {
-	statedb := state.(EthApiState).state
-	from := statedb.GetOrNewStateObject(msg.From())
-	from.SetBalance(math.MaxBig256)
+func (b *EthApiBackend) GetEVM(ctx context.Context, msg core.Message, state *state.StateDB, header *types.Header, vmCfg vm.Config) (*vm.EVM, func() error, error) {
+	state.SetBalance(msg.From(), math.MaxBig256)
 	vmError := func() error { return nil }
 
 	context := core.NewEVMContext(msg, header, b.eth.BlockChain(), nil)
-	return vm.NewEVM(context, statedb, b.eth.chainConfig, vmCfg), vmError, nil
+	return vm.NewEVM(context, state, b.eth.chainConfig, vmCfg), vmError, nil
 }
 
 func (b *EthApiBackend) SendTx(ctx context.Context, signedTx *types.Transaction) error {
@@ -200,23 +197,3 @@ func (b *EthApiBackend) EventMux() *event.TypeMux {
 func (b *EthApiBackend) AccountManager() *accounts.Manager {
 	return b.eth.AccountManager()
 }
-
-type EthApiState struct {
-	state *state.StateDB
-}
-
-func (s EthApiState) GetBalance(ctx context.Context, addr common.Address) (*big.Int, error) {
-	return s.state.GetBalance(addr), nil
-}
-
-func (s EthApiState) GetCode(ctx context.Context, addr common.Address) ([]byte, error) {
-	return s.state.GetCode(addr), nil
-}
-
-func (s EthApiState) GetState(ctx context.Context, a common.Address, b common.Hash) (common.Hash, error) {
-	return s.state.GetState(a, b), nil
-}
-
-func (s EthApiState) GetNonce(ctx context.Context, addr common.Address) (uint64, error) {
-	return s.state.GetNonce(addr), nil
-}
diff --git a/eth/api_test.go b/eth/api_test.go
index f8d2e9c76..49ce38688 100644
--- a/eth/api_test.go
+++ b/eth/api_test.go
@@ -32,7 +32,7 @@ func TestStorageRangeAt(t *testing.T) {
 	// Create a state where account 0x010000... has a few storage entries.
 	var (
 		db, _    = ethdb.NewMemDatabase()
-		state, _ = state.New(common.Hash{}, db)
+		state, _ = state.New(common.Hash{}, state.NewDatabase(db))
 		addr     = common.Address{0x01}
 		keys     = []common.Hash{ // hashes of Keys of storage
 			common.HexToHash("340dd630ad21bf010b4e676dbfa9ba9a02175262d1fa356232cfde6cb5b47ef2"),
diff --git a/eth/bind.go b/eth/bind.go
index e5abd8617..0385db1f9 100644
--- a/eth/bind.go
+++ b/eth/bind.go
@@ -54,14 +54,12 @@ func NewContractBackend(apiBackend ethapi.Backend) *ContractBackend {
 
 // CodeAt retrieves any code associated with the contract from the local API.
 func (b *ContractBackend) CodeAt(ctx context.Context, contract common.Address, blockNum *big.Int) ([]byte, error) {
-	out, err := b.bcapi.GetCode(ctx, contract, toBlockNumber(blockNum))
-	return common.FromHex(out), err
+	return b.bcapi.GetCode(ctx, contract, toBlockNumber(blockNum))
 }
 
 // CodeAt retrieves any code associated with the contract from the local API.
 func (b *ContractBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
-	out, err := b.bcapi.GetCode(ctx, contract, rpc.PendingBlockNumber)
-	return common.FromHex(out), err
+	return b.bcapi.GetCode(ctx, contract, rpc.PendingBlockNumber)
 }
 
 // ContractCall implements bind.ContractCaller executing an Ethereum contract
diff --git a/eth/downloader/downloader_test.go b/eth/downloader/downloader_test.go
index 267a0def9..1fb5a0910 100644
--- a/eth/downloader/downloader_test.go
+++ b/eth/downloader/downloader_test.go
@@ -657,7 +657,7 @@ func assertOwnForkedChain(t *testing.T, tester *downloadTester, common int, leng
 			index = len(tester.ownHashes) - lengths[len(lengths)-1] + int(tester.downloader.queue.fastSyncPivot)
 		}
 		if index > 0 {
-			if statedb, err := state.New(tester.ownHeaders[tester.ownHashes[index]].Root, tester.stateDb); statedb == nil || err != nil {
+			if statedb, err := state.New(tester.ownHeaders[tester.ownHashes[index]].Root, state.NewDatabase(tester.stateDb)); statedb == nil || err != nil {
 				t.Fatalf("state reconstruction failed: %v", err)
 			}
 		}
diff --git a/eth/handler_test.go b/eth/handler_test.go
index 413ed2bff..ca9c9e1b4 100644
--- a/eth/handler_test.go
+++ b/eth/handler_test.go
@@ -374,7 +374,7 @@ func testGetNodeData(t *testing.T, protocol int) {
 	}
 	accounts := []common.Address{testBank, acc1Addr, acc2Addr}
 	for i := uint64(0); i <= pm.blockchain.CurrentBlock().NumberU64(); i++ {
-		trie, _ := state.New(pm.blockchain.GetBlockByNumber(i).Root(), statedb)
+		trie, _ := state.New(pm.blockchain.GetBlockByNumber(i).Root(), state.NewDatabase(statedb))
 
 		for j, acc := range accounts {
 			state, _ := pm.blockchain.State()