Partial stateDB implementation

state/statedb.go

@@ -3,6 +3,8 @@ package state
 import (
 	"fmt"
 	"math/big"
+	"sort"
+	"sync"
 
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/cosmos/cosmos-sdk/x/auth"
@@ -10,10 +12,18 @@ import (
 	ethcmn "github.com/ethereum/go-ethereum/common"
 	ethstate "github.com/ethereum/go-ethereum/core/state"
 	ethtypes "github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
 )
 
-var _ ethstate.StateDB = (*CommitStateDB)(nil)
+var (
+	_ ethstate.StateDB = (*CommitStateDB)(nil)
 
+	zeroBalance = sdk.ZeroInt().BigInt()
+)
+
+// CommitStateDB implements the Geth state.StateDB interface. Instead of using
+// a trie and database for querying and persistence, KVStores and an account
+// mapper is used to facilitate state transitions.
 type CommitStateDB struct {
 	// TODO: Figure out a way to not need to store a context as part of the
 	// structure
@@ -21,17 +31,25 @@ type CommitStateDB struct {
 
 	am         auth.AccountMapper
 	storageKey sdk.StoreKey
+	codeKey    sdk.StoreKey
 
 	// maps that hold 'live' objects, which will get modified while processing a
 	// state transition
+	//
+	// TODO: Determine if we need this cache as the KVStore is cache-wrapped
 	stateObjects      map[ethcmn.Address]*stateObject
 	stateObjectsDirty map[ethcmn.Address]struct{}
 
+	// The refund counter, also used by state transitioning.
+	refund uint64
+
 	thash, bhash ethcmn.Hash
 	txIndex      int
 	logs         map[ethcmn.Hash][]*ethtypes.Log
 	logSize      uint
 
+	preimages map[ethcmn.Hash][]byte
+
 	// DB error.
 	// State objects are used by the consensus core and VM which are
 	// unable to deal with database-level errors. Any error that occurs
@@ -44,23 +62,502 @@ type CommitStateDB struct {
 	journal        *journal
 	validRevisions []ethstate.Revision
 	nextRevisionID int
+
+	// mutex for state deep copying
+	lock sync.Mutex
 }
 
-func NewCommitStateDB(ctx sdk.Context) (*CommitStateDB, error) {
+// TODO: Make sure storage is prefixed with address!!!
-	// tr, err := db.OpenTrie(root)
-	// if err != nil {
-	// 	return nil, err
-	// }
 
+func NewCommitStateDB(ctx sdk.Context) (*CommitStateDB, error) {
 	return &CommitStateDB{
-		// stateObjects:      make(map[ethcmn.Address]*stateObject),
+		stateObjects:      make(map[ethcmn.Address]*stateObject),
-		// stateObjectsDirty: make(map[ethcmn.Address]struct{}),
+		stateObjectsDirty: make(map[ethcmn.Address]struct{}),
-		// logs:              make(map[ethcmn.Hash][]*types.Log),
+		logs:              make(map[ethcmn.Hash][]*ethtypes.Log),
-		// preimages:         make(map[ethcmn.Hash][]byte),
 		journal:           newJournal(),
 	}, nil
 }
 
+// ----------------------------------------------------------------------------
+// Setters
+// ----------------------------------------------------------------------------
+
+// SetBalance sets the balance of an account.
+func (csdb *CommitStateDB) SetBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetBalance(amount)
+	}
+}
+
+// AddBalance adds amount to the account associated with addr.
+func (csdb *CommitStateDB) AddBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.AddBalance(amount)
+	}
+}
+
+// SubBalance subtracts amount from the account associated with addr.
+func (csdb *CommitStateDB) SubBalance(addr ethcmn.Address, amount *big.Int) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SubBalance(amount)
+	}
+}
+
+// SetNonce sets the nonce (sequence number) of an account.
+func (csdb *CommitStateDB) SetNonce(addr ethcmn.Address, nonce uint64) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetNonce(nonce)
+	}
+}
+
+// SetState sets the storage state with a key, value pair for an account.
+func (csdb *CommitStateDB) SetState(addr ethcmn.Address, key, value ethcmn.Hash) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetState(nil, key, value)
+	}
+}
+
+// SetCode sets the code for a given account.
+func (csdb *CommitStateDB) SetCode(addr ethcmn.Address, code []byte) {
+	so := csdb.GetOrNewStateObject(addr)
+	if so != nil {
+		so.SetCode(crypto.Keccak256Hash(code), code)
+	}
+}
+
+// AddLog adds a new log to the state and sets the log metadata from the state.
+func (csdb *CommitStateDB) AddLog(log *ethtypes.Log) {
+	csdb.journal.append(addLogChange{txhash: csdb.thash})
+
+	log.TxHash = csdb.thash
+	log.BlockHash = csdb.bhash
+	log.TxIndex = uint(csdb.txIndex)
+	log.Index = csdb.logSize
+	csdb.logs[csdb.thash] = append(csdb.logs[csdb.thash], log)
+	csdb.logSize++
+}
+
+// AddPreimage records a SHA3 preimage seen by the VM.
+func (csdb *CommitStateDB) AddPreimage(hash ethcmn.Hash, preimage []byte) {
+	if _, ok := csdb.preimages[hash]; !ok {
+		csdb.journal.append(addPreimageChange{hash: hash})
+
+		pi := make([]byte, len(preimage))
+		copy(pi, preimage)
+		csdb.preimages[hash] = pi
+	}
+}
+
+// AddRefund adds gas to the refund counter.
+func (csdb *CommitStateDB) AddRefund(gas uint64) {
+	csdb.journal.append(refundChange{prev: csdb.refund})
+	csdb.refund += gas
+}
+
+// SubRefund removes gas from the refund counter. It will panic if the refund
+// counter goes below zero.
+func (csdb *CommitStateDB) SubRefund(gas uint64) {
+	csdb.journal.append(refundChange{prev: csdb.refund})
+	if gas > csdb.refund {
+		panic("refund counter below zero")
+	}
+
+	csdb.refund -= gas
+}
+
+// ----------------------------------------------------------------------------
+// Getters
+// ----------------------------------------------------------------------------
+
+// GetBalance retrieves the balance from the given address or 0 if object not
+// found.
+func (csdb *CommitStateDB) GetBalance(addr ethcmn.Address) *big.Int {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Balance()
+	}
+
+	return zeroBalance
+}
+
+// GetNonce returns the nonce (sequence number) for a given account.
+func (csdb *CommitStateDB) GetNonce(addr ethcmn.Address) uint64 {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Nonce()
+	}
+
+	return 0
+}
+
+// GetCode returns the code for a given account.
+func (csdb *CommitStateDB) GetCode(addr ethcmn.Address) []byte {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.Code(nil)
+	}
+
+	return nil
+}
+
+// GetCodeSize returns the code size for a given account.
+func (csdb *CommitStateDB) GetCodeSize(addr ethcmn.Address) int {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return 0
+	}
+
+	if so.code != nil {
+		return len(so.code)
+	}
+
+	// TODO: we may need to cache these lookups directly
+	return len(so.Code(nil))
+}
+
+// GetCodeHash returns the code hash for a given account.
+func (csdb *CommitStateDB) GetCodeHash(addr ethcmn.Address) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return ethcmn.Hash{}
+	}
+
+	return ethcmn.BytesToHash(so.CodeHash())
+}
+
+// GetState retrieves a value from the given account's storage store.
+func (csdb *CommitStateDB) GetState(addr ethcmn.Address, hash ethcmn.Hash) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.GetState(nil, hash)
+	}
+
+	return ethcmn.Hash{}
+}
+
+// GetCommittedState retrieves a value from the given account's committed
+// storage.
+func (csdb *CommitStateDB) GetCommittedState(addr ethcmn.Address, hash ethcmn.Hash) ethcmn.Hash {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.GetCommittedState(nil, hash)
+	}
+
+	return ethcmn.Hash{}
+}
+
+// GetLogs returns the current logs for a given hash in the state.
+func (csdb *CommitStateDB) GetLogs(hash ethcmn.Hash) []*ethtypes.Log {
+	return csdb.logs[hash]
+}
+
+// Logs returns all the current logs in the state.
+func (csdb *CommitStateDB) Logs() []*ethtypes.Log {
+	var logs []*ethtypes.Log
+	for _, lgs := range csdb.logs {
+		logs = append(logs, lgs...)
+	}
+
+	return logs
+}
+
+// GetRefund returns the current value of the refund counter.
+func (csdb *CommitStateDB) GetRefund() uint64 {
+	return csdb.refund
+}
+
+// Preimages returns a list of SHA3 preimages that have been submitted.
+func (csdb *CommitStateDB) Preimages() map[ethcmn.Hash][]byte {
+	return csdb.preimages
+}
+
+// HasSuicided returns if the given account for the specified address has been
+// killed.
+func (csdb *CommitStateDB) HasSuicided(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	if so != nil {
+		return so.suicided
+	}
+
+	return false
+}
+
+// StorageTrie returns nil as the state in Ethermint does not use a direct
+// storage trie.
+func (csdb *CommitStateDB) StorageTrie(addr ethcmn.Address) ethstate.Trie {
+	return nil
+}
+
+// ----------------------------------------------------------------------------
+// Persistance
+// ----------------------------------------------------------------------------
+
+// TODO: Commit writes the state ...
+func (csdb *CommitStateDB) Commit(deleteEmptyObjects bool) (root ethcmn.Hash, err error) {
+	// TODO: ...
+	return
+}
+
+// TODO: ...
+func (csdb *CommitStateDB) Finalize(deleteEmptyObjects bool) {
+	// TODO: ...
+}
+
+// IntermediateRoot computes the current root hash of the state trie.
+// It is called in between transactions to get the root hash that
+// goes into transaction receipts.
+func (csdb *CommitStateDB) IntermediateRoot(deleteEmptyObjects bool) ethcmn.Hash {
+	// TODO: ...
+	// csdb.Finalize(deleteEmptyObjects)
+	// return csdb.trie.Hash()
+}
+
+// ----------------------------------------------------------------------------
+// Snapshotting
+// ----------------------------------------------------------------------------
+
+// Snapshot returns an identifier for the current revision of the state.
+func (csdb *CommitStateDB) Snapshot() int {
+	id := csdb.nextRevisionID
+	csdb.nextRevisionID++
+	csdb.validRevisions = append(csdb.validRevisions, ethstate.Revision{id, csdb.journal.length()})
+	return id
+}
+
+// RevertToSnapshot reverts all state changes made since the given revision.
+func (csdb *CommitStateDB) RevertToSnapshot(revID int) {
+	// find the snapshot in the stack of valid snapshots
+	idx := sort.Search(len(csdb.validRevisions), func(i int) bool {
+		return csdb.validRevisions[i].ID >= revID
+	})
+
+	if idx == len(csdb.validRevisions) || csdb.validRevisions[idx].ID != revID {
+		panic(fmt.Errorf("revision ID %v cannot be reverted", revID))
+	}
+
+	snapshot := csdb.validRevisions[idx].JournalIndex
+
+	// replay the journal to undo changes and remove invalidated snapshots
+	csdb.journal.revert(csdb, snapshot)
+	csdb.validRevisions = csdb.validRevisions[:idx]
+}
+
+// ----------------------------------------------------------------------------
+// Auxiliary
+// ----------------------------------------------------------------------------
+
+// Suicide marks the given account as suicided and clears the account balance.
+//
+// The account's state object is still available until the state is committed,
+// getStateObject will return a non-nil account after Suicide.
+func (csdb *CommitStateDB) Suicide(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return false
+	}
+
+	csdb.journal.append(suicideChange{
+		account:     &addr,
+		prev:        so.suicided,
+		prevBalance: sdk.NewIntFromBigInt(so.Balance()),
+	})
+
+	so.markSuicided()
+	so.SetBalance(new(big.Int))
+
+	return true
+}
+
+// Reset clears out all ephemeral state objects from the state db, but keeps
+// the underlying account mapper and store keys to avoid reloading data for the
+// next operations.
+func (csdb *CommitStateDB) Reset(root ethcmn.Hash) error {
+	csdb.stateObjects = make(map[ethcmn.Address]*stateObject)
+	csdb.stateObjectsDirty = make(map[ethcmn.Address]struct{})
+	csdb.thash = ethcmn.Hash{}
+	csdb.bhash = ethcmn.Hash{}
+	csdb.txIndex = 0
+	csdb.logs = make(map[ethcmn.Hash][]*ethtypes.Log)
+	csdb.logSize = 0
+	csdb.preimages = make(map[ethcmn.Hash][]byte)
+
+	csdb.clearJournalAndRefund()
+	return nil
+}
+
+func (csdb *CommitStateDB) clearJournalAndRefund() {
+	csdb.journal = newJournal()
+	csdb.validRevisions = csdb.validRevisions[:0]
+	csdb.refund = 0
+}
+
+// Prepare sets the current transaction hash and index and block hash which is
+// used when the EVM emits new state logs.
+func (csdb *CommitStateDB) Prepare(thash, bhash ethcmn.Hash, txi int) {
+	csdb.thash = thash
+	csdb.bhash = bhash
+	csdb.txIndex = txi
+}
+
+// CreateAccount explicitly creates a state object. If a state object with the
+// address already exists the balance is carried over to the new account.
+//
+// CreateAccount is called during the EVM CREATE operation. The situation might
+// arise that a contract does the following:
+//
+//   1. sends funds to sha(account ++ (nonce + 1))
+//   2. tx_create(sha(account ++ nonce)) (note that this gets the address of 1)
+//
+// Carrying over the balance ensures that Ether doesn't disappear.
+func (csdb *CommitStateDB) CreateAccount(addr ethcmn.Address) {
+	newobj, prevobj := csdb.createObject(addr)
+	if prevobj != nil {
+		newobj.setBalance(sdk.NewIntFromBigInt(prevobj.Balance()))
+	}
+}
+
+// Copy creates a deep, independent copy of the state.
+//
+// NOTE: Snapshots of the copied state cannot be applied to the copy.
+func (csdb *CommitStateDB) Copy() ethstate.StateDB {
+	csdb.lock.Lock()
+	defer csdb.lock.Unlock()
+
+	// copy all the basic fields, initialize the memory ones
+	state := &CommitStateDB{
+		ctx:               csdb.ctx,
+		am:                csdb.am,
+		storageKey:        csdb.storageKey,
+		codeKey:           csdb.codeKey,
+		stateObjects:      make(map[ethcmn.Address]*stateObject, len(csdb.journal.dirties)),
+		stateObjectsDirty: make(map[ethcmn.Address]struct{}, len(csdb.journal.dirties)),
+		refund:            csdb.refund,
+		logs:              make(map[ethcmn.Hash][]*ethtypes.Log, len(csdb.logs)),
+		logSize:           csdb.logSize,
+		preimages:         make(map[ethcmn.Hash][]byte),
+		journal:           newJournal(),
+	}
+
+	// copy the dirty states, logs, and preimages
+	for addr := range csdb.journal.dirties {
+		// There is a case where an object is in the journal but not in the
+		// stateObjects: OOG after touch on ripeMD prior to Byzantium. Thus, we
+		// need to check for nil.
+		//
+		// Ref: https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527
+		if object, exist := csdb.stateObjects[addr]; exist {
+			state.stateObjects[addr] = object.deepCopy(state)
+			state.stateObjectsDirty[addr] = struct{}{}
+		}
+	}
+
+	// Above, we don't copy the actual journal. This means that if the copy is
+	// copied, the loop above will be a no-op, since the copy's journal is empty.
+	// Thus, here we iterate over stateObjects, to enable copies of copies.
+	for addr := range csdb.stateObjectsDirty {
+		if _, exist := state.stateObjects[addr]; !exist {
+			state.stateObjects[addr] = csdb.stateObjects[addr].deepCopy(state)
+			state.stateObjectsDirty[addr] = struct{}{}
+		}
+	}
+
+	// copy logs
+	for hash, logs := range csdb.logs {
+		cpy := make([]*ethtypes.Log, len(logs))
+		for i, l := range logs {
+			cpy[i] = new(ethtypes.Log)
+			*cpy[i] = *l
+		}
+		state.logs[hash] = cpy
+	}
+
+	// copy pre-images
+	for hash, preimage := range csdb.preimages {
+		state.preimages[hash] = preimage
+	}
+
+	return state
+}
+
+// ForEachStorage iterates over each storage items, all invokes the provided
+// callback on each key, value pair .
+func (csdb *CommitStateDB) ForEachStorage(addr ethcmn.Address, cb func(key, value ethcmn.Hash) bool) {
+	so := csdb.getStateObject(addr)
+	if so == nil {
+		return
+	}
+
+	store := csdb.ctx.KVStore(csdb.storageKey)
+	iter := sdk.KVStorePrefixIterator(store, so.Address().Bytes())
+
+	for ; iter.Valid(); iter.Next() {
+		key := ethcmn.BytesToHash(iter.Key())
+		value := iter.Value()
+
+		if value, dirty := so.dirtyStorage[key]; dirty {
+			cb(key, value)
+			continue
+		}
+
+		cb(key, ethcmn.BytesToHash(value))
+	}
+
+	iter.Close()
+}
+
+// GetOrNewStateObject retrieves a state object or create a new state object if
+// nil.
+func (csdb *CommitStateDB) GetOrNewStateObject(addr ethcmn.Address) ethstate.StateObject {
+	so := csdb.getStateObject(addr)
+	if so == nil || so.deleted {
+		so, _ = csdb.createObject(addr)
+	}
+
+	return so
+}
+
+// createObject creates a new state object. If there is an existing account with
+// the given address, it is overwritten and returned as the second return value.
+func (csdb *CommitStateDB) createObject(addr ethcmn.Address) (newObj, prevObj *stateObject) {
+	prevObj = csdb.getStateObject(addr)
+
+	acc := csdb.am.NewAccountWithAddress(csdb.ctx, sdk.AccAddress(addr.Bytes()))
+	newObj = newObject(csdb, acc)
+	newObj.setNonce(0) // sets the object to dirty
+
+	if prevObj == nil {
+		csdb.journal.append(createObjectChange{account: &addr})
+	} else {
+		csdb.journal.append(resetObjectChange{prev: prevObj})
+	}
+
+	csdb.setStateObject(newObj)
+	return newObj, prevObj
+}
+
+// Empty returns whether the state object is either non-existent or empty
+// according to the EIP161 specification (balance = nonce = code = 0).
+func (csdb *CommitStateDB) Empty(addr ethcmn.Address) bool {
+	so := csdb.getStateObject(addr)
+	return so == nil || so.empty()
+}
+
+// Exist reports whether the given account address exists in the state. Notably,
+// this also returns true for suicided accounts.
+func (csdb *CommitStateDB) Exist(addr ethcmn.Address) bool {
+	return csdb.getStateObject(addr) != nil
+}
+
+// Error returns the first non-nil error the StateDB encountered.
+func (csdb *CommitStateDB) Error() error {
+	return csdb.dbErr
+}
+
 // setError remembers the first non-nil error it is called with.
 func (csdb *CommitStateDB) setError(err error) {
 	if csdb.dbErr == nil {
@@ -68,22 +565,8 @@ func (csdb *CommitStateDB) setError(err error) {
 	}
 }
 
-// Error returns the first non-nil error the StateDB encountered.
+// getStateObject attempts to retrieve a state object given by the address.
-func (csdb *CommitStateDB) Error() error {
+// Returns nil and sets an error if not found.
-	return csdb.dbErr
-}
-
-// Retrieve the balance from the given address or 0 if object not found
-func (csdb *CommitStateDB) GetBalance(addr ethcmn.Address) *big.Int {
-	stateObject := csdb.getStateObject(addr)
-	if stateObject != nil {
-		return stateObject.Balance()
-	}
-
-	return common.Big0
-}
-
-// Retrieve a state object given by the address. Returns nil if not found.
 func (csdb *CommitStateDB) getStateObject(addr ethcmn.Address) (stateObject *stateObject) {
 	// prefer 'live' (cached) objects
 	if obj := csdb.stateObjects[addr]; obj != nil {
@@ -94,9 +577,11 @@ func (csdb *CommitStateDB) getStateObject(addr ethcmn.Address) (stateObject *sta
 		return obj
 	}
 
+	// otherwise, attempt to fetch the account from the account mapper
 	acc := csdb.am.GetAccount(csdb.ctx, addr.Bytes())
 	if acc == nil {
 		csdb.setError(fmt.Errorf("no account found for address: %X", addr.Bytes()))
+		return nil
 	}
 
 	// insert the state object into the live set
@@ -108,3 +593,9 @@ func (csdb *CommitStateDB) getStateObject(addr ethcmn.Address) (stateObject *sta
 func (csdb *CommitStateDB) setStateObject(object *stateObject) {
 	csdb.stateObjects[object.Address()] = object
 }
+
+// Database retrieves the low level database supporting the lower level trie
+// ops. It is not used in Ethermint, so it returns nil.
+func (csdb *CommitStateDB) Database() ethstate.Database {
+	return nil
+}