// Copyright 2014 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see . // Package state provides a caching layer atop the Ethereum state trie. package state import ( "errors" "fmt" "math/big" "sort" "github.com/harmony-one/harmony/numeric" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/crypto" "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/rlp" "github.com/ethereum/go-ethereum/trie" "github.com/harmony-one/harmony/core/types" "github.com/harmony-one/harmony/staking" stk "github.com/harmony-one/harmony/staking/types" ) type revision struct { id int journalIndex int } var ( // emptyState is the known hash of an empty state trie entry. emptyState = crypto.Keccak256Hash(nil) // emptyCode is the known hash of the empty EVM bytecode. emptyCode = crypto.Keccak256Hash(nil) ) type proofList [][]byte func (n *proofList) Put(key []byte, value []byte) error { *n = append(*n, value) return nil } // DB within the ethereum protocol are used to store anything // within the merkle trie. StateDBs take care of caching and storing // nested states. It's the general query interface to retrieve: // * Contracts // * Accounts type DB struct { db Database trie Trie // This map holds 'live' objects, which will get modified while processing a state transition. stateObjects map[common.Address]*Object stateObjectsDirty map[common.Address]struct{} // 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 // during a database read is memoized here and will eventually be returned // by DB.Commit. dbErr error // The refund counter, also used by state transitioning. refund uint64 thash, bhash common.Hash txIndex int logs map[common.Hash][]*types.Log logSize uint preimages map[common.Hash][]byte // Journal of state modifications. This is the backbone of // Snapshot and RevertToSnapshot. journal *journal validRevisions []revision nextRevisionID int } // New creates a new state from a given trie. func New(root common.Hash, db Database) (*DB, error) { tr, err := db.OpenTrie(root) if err != nil { return nil, err } return &DB{ db: db, trie: tr, stateObjects: make(map[common.Address]*Object), stateObjectsDirty: make(map[common.Address]struct{}), logs: make(map[common.Hash][]*types.Log), preimages: make(map[common.Hash][]byte), journal: newJournal(), }, nil } // setError remembers the first non-nil error it is called with. func (db *DB) setError(err error) { if db.dbErr == nil { db.dbErr = err } } func (db *DB) Error() error { return db.dbErr } // Reset clears out all ephemeral state objects from the state db, but keeps // the underlying state trie to avoid reloading data for the next operations. func (db *DB) Reset(root common.Hash) error { tr, err := db.db.OpenTrie(root) if err != nil { return err } db.trie = tr db.stateObjects = make(map[common.Address]*Object) db.stateObjectsDirty = make(map[common.Address]struct{}) db.thash = common.Hash{} db.bhash = common.Hash{} db.txIndex = 0 db.logs = make(map[common.Hash][]*types.Log) db.logSize = 0 db.preimages = make(map[common.Hash][]byte) db.clearJournalAndRefund() return nil } // AddLog ... func (db *DB) AddLog(log *types.Log) { db.journal.append(addLogChange{txhash: db.thash}) log.TxHash = db.thash log.BlockHash = db.bhash log.TxIndex = uint(db.txIndex) log.Index = db.logSize db.logs[db.thash] = append(db.logs[db.thash], log) db.logSize++ } // GetLogs ... func (db *DB) GetLogs(hash common.Hash) []*types.Log { return db.logs[hash] } // Logs ... func (db *DB) Logs() []*types.Log { var logs []*types.Log for _, lgs := range db.logs { logs = append(logs, lgs...) } return logs } // AddPreimage records a SHA3 preimage seen by the VM. func (db *DB) AddPreimage(hash common.Hash, preimage []byte) { if _, ok := db.preimages[hash]; !ok { db.journal.append(addPreimageChange{hash: hash}) pi := make([]byte, len(preimage)) copy(pi, preimage) db.preimages[hash] = pi } } // Preimages returns a list of SHA3 preimages that have been submitted. func (db *DB) Preimages() map[common.Hash][]byte { return db.preimages } // AddRefund adds gas to the refund counter func (db *DB) AddRefund(gas uint64) { db.journal.append(refundChange{prev: db.refund}) db.refund += gas } // SubRefund removes gas from the refund counter. // This method will panic if the refund counter goes below zero func (db *DB) SubRefund(gas uint64) { db.journal.append(refundChange{prev: db.refund}) if gas > db.refund { panic("Refund counter below zero") } db.refund -= gas } // Exist reports whether the given account address exists in the state. // Notably this also returns true for suicided accounts. func (db *DB) Exist(addr common.Address) bool { return db.getStateObject(addr) != nil } // Empty returns whether the state object is either non-existent // or empty according to the EIP161 specification (balance = nonce = code = 0) func (db *DB) Empty(addr common.Address) bool { so := db.getStateObject(addr) return so == nil || so.empty() } // GetBalance retrieves the balance from the given address or 0 if object not found func (db *DB) GetBalance(addr common.Address) *big.Int { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.Balance() } return common.Big0 } // GetNonce ... func (db *DB) GetNonce(addr common.Address) uint64 { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.Nonce() } return 0 } // GetCode ... func (db *DB) GetCode(addr common.Address) []byte { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.Code(db.db) } return nil } // GetCodeSize ... func (db *DB) GetCodeSize(addr common.Address) int { stateObject := db.getStateObject(addr) if stateObject == nil { return 0 } if stateObject.code != nil { return len(stateObject.code) } size, err := db.db.ContractCodeSize(stateObject.addrHash, common.BytesToHash(stateObject.CodeHash())) if err != nil { db.setError(err) } return size } // GetCodeHash ... func (db *DB) GetCodeHash(addr common.Address) common.Hash { stateObject := db.getStateObject(addr) if stateObject == nil { return common.Hash{} } return common.BytesToHash(stateObject.CodeHash()) } // GetState retrieves a value from the given account's storage trie. func (db *DB) GetState(addr common.Address, hash common.Hash) common.Hash { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.GetState(db.db, hash) } return common.Hash{} } // GetProof returns the MerkleProof for a given Account func (db *DB) GetProof(a common.Address) ([][]byte, error) { var proof proofList err := db.trie.Prove(crypto.Keccak256(a.Bytes()), 0, &proof) return [][]byte(proof), err } // GetStorageProof returns the StorageProof for given key func (db *DB) GetStorageProof(a common.Address, key common.Hash) ([][]byte, error) { var proof proofList trie := db.StorageTrie(a) if trie == nil { return proof, errors.New("storage trie for requested address does not exist") } err := trie.Prove(crypto.Keccak256(key.Bytes()), 0, &proof) return [][]byte(proof), err } // GetCommittedState retrieves a value from the given account's committed storage trie. func (db *DB) GetCommittedState(addr common.Address, hash common.Hash) common.Hash { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.GetCommittedState(db.db, hash) } return common.Hash{} } // Database retrieves the low level database supporting the lower level trie ops. func (db *DB) Database() Database { return db.db } // StorageTrie returns the storage trie of an account. // The return value is a copy and is nil for non-existent accounts. func (db *DB) StorageTrie(addr common.Address) Trie { stateObject := db.getStateObject(addr) if stateObject == nil { return nil } cpy := stateObject.deepCopy(db) return cpy.updateTrie(db.db) } // HasSuicided ... func (db *DB) HasSuicided(addr common.Address) bool { stateObject := db.getStateObject(addr) if stateObject != nil { return stateObject.suicided } return false } /* * SETTERS */ // AddBalance adds amount to the account associated with addr. func (db *DB) AddBalance(addr common.Address, amount *big.Int) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.AddBalance(amount) } } // SubBalance subtracts amount from the account associated with addr. func (db *DB) SubBalance(addr common.Address, amount *big.Int) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SubBalance(amount) } } // SetBalance ... func (db *DB) SetBalance(addr common.Address, amount *big.Int) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetBalance(amount) } } // SetNonce ... func (db *DB) SetNonce(addr common.Address, nonce uint64) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetNonce(nonce) } } // SetCode ... func (db *DB) SetCode(addr common.Address, code []byte) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetCode(crypto.Keccak256Hash(code), code) } } // SetState ... func (db *DB) SetState(addr common.Address, key, value common.Hash) { stateObject := db.GetOrNewStateObject(addr) if stateObject != nil { stateObject.SetState(db.db, key, value) } } // Suicide marks the given account as suicided. // This 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 (db *DB) Suicide(addr common.Address) bool { stateObject := db.getStateObject(addr) if stateObject == nil { return false } db.journal.append(suicideChange{ account: &addr, prev: stateObject.suicided, prevbalance: new(big.Int).Set(stateObject.Balance()), }) stateObject.markSuicided() stateObject.data.Balance = new(big.Int) return true } // // Setting, updating & deleting state object methods. // // updateStateObject writes the given object to the trie. func (db *DB) updateStateObject(stateObject *Object) { addr := stateObject.Address() data, err := rlp.EncodeToBytes(stateObject) if err != nil { panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err)) } db.setError(db.trie.TryUpdate(addr[:], data)) } // deleteStateObject removes the given object from the state trie. func (db *DB) deleteStateObject(stateObject *Object) { stateObject.deleted = true addr := stateObject.Address() db.setError(db.trie.TryDelete(addr[:])) } // Retrieve a state object given by the address. Returns nil if not found. func (db *DB) getStateObject(addr common.Address) (stateObject *Object) { // Prefer 'live' objects. if obj := db.stateObjects[addr]; obj != nil { if obj.deleted { return nil } return obj } // Load the object from the database. enc, err := db.trie.TryGet(addr[:]) if len(enc) == 0 { db.setError(err) return nil } var data Account if err := rlp.DecodeBytes(enc, &data); err != nil { log.Error("Failed to decode state object", "addr", addr, "err", err) return nil } // Insert into the live set. obj := newObject(db, addr, data) db.setStateObject(obj) return obj } func (db *DB) setStateObject(object *Object) { db.stateObjects[object.Address()] = object } // GetOrNewStateObject retrieves a state object or create a new state object if nil. func (db *DB) GetOrNewStateObject(addr common.Address) *Object { stateObject := db.getStateObject(addr) if stateObject == nil || stateObject.deleted { stateObject, _ = db.createObject(addr) } return stateObject } // 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 (db *DB) createObject(addr common.Address) (newobj, prev *Object) { prev = db.getStateObject(addr) newobj = newObject(db, addr, Account{}) newobj.setNonce(0) // sets the object to dirty if prev == nil { db.journal.append(createObjectChange{account: &addr}) } else { db.journal.append(resetObjectChange{prev: prev}) } db.setStateObject(newobj) return newobj, prev } // 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 (db *DB) CreateAccount(addr common.Address) { newObj, prev := db.createObject(addr) if prev != nil { newObj.setBalance(prev.data.Balance) } } // ForEachStorage ... func (db *DB) ForEachStorage(addr common.Address, cb func(key, value common.Hash) bool) { so := db.getStateObject(addr) if so == nil { return } it := trie.NewIterator(so.getTrie(db.db).NodeIterator(nil)) for it.Next() { key := common.BytesToHash(db.trie.GetKey(it.Key)) if value, dirty := so.dirtyStorage[key]; dirty { cb(key, value) continue } cb(key, common.BytesToHash(it.Value)) } } // Copy creates a deep, independent copy of the state. // Snapshots of the copied state cannot be applied to the copy. func (db *DB) Copy() *DB { // Copy all the basic fields, initialize the memory ones state := &DB{ db: db.db, trie: db.db.CopyTrie(db.trie), stateObjects: make(map[common.Address]*Object, len(db.journal.dirties)), stateObjectsDirty: make(map[common.Address]struct{}, len(db.journal.dirties)), refund: db.refund, logs: make(map[common.Hash][]*types.Log, len(db.logs)), logSize: db.logSize, preimages: make(map[common.Hash][]byte), journal: newJournal(), } // Copy the dirty states, logs, and preimages for addr := range db.journal.dirties { // As documented [here](https://github.com/ethereum/go-ethereum/pull/16485#issuecomment-380438527), // and in the Finalise-method, 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 if object, exist := db.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 db.stateObjectsDirty { if _, exist := state.stateObjects[addr]; !exist { state.stateObjects[addr] = db.stateObjects[addr].deepCopy(state) state.stateObjectsDirty[addr] = struct{}{} } } for hash, logs := range db.logs { cpy := make([]*types.Log, len(logs)) for i, l := range logs { cpy[i] = new(types.Log) *cpy[i] = *l } state.logs[hash] = cpy } for hash, preimage := range db.preimages { state.preimages[hash] = preimage } return state } // Snapshot returns an identifier for the current revision of the state. func (db *DB) Snapshot() int { id := db.nextRevisionID db.nextRevisionID++ db.validRevisions = append(db.validRevisions, revision{id, db.journal.length()}) return id } // RevertToSnapshot reverts all state changes made since the given revision. func (db *DB) RevertToSnapshot(revid int) { // Find the snapshot in the stack of valid snapshots. idx := sort.Search(len(db.validRevisions), func(i int) bool { return db.validRevisions[i].id >= revid }) if idx == len(db.validRevisions) || db.validRevisions[idx].id != revid { panic(fmt.Errorf("revision id %v cannot be reverted", revid)) } snapshot := db.validRevisions[idx].journalIndex // Replay the journal to undo changes and remove invalidated snapshots db.journal.revert(db, snapshot) db.validRevisions = db.validRevisions[:idx] } // GetRefund returns the current value of the refund counter. func (db *DB) GetRefund() uint64 { return db.refund } // Finalise finalises the state by removing the db destructed objects // and clears the journal as well as the refunds. func (db *DB) Finalise(deleteEmptyObjects bool) { for addr := range db.journal.dirties { stateObject, exist := db.stateObjects[addr] if !exist { // ripeMD is 'touched' at block 1714175, in tx 0x1237f737031e40bcde4a8b7e717b2d15e3ecadfe49bb1bbc71ee9deb09c6fcf2 // That tx goes out of gas, and although the notion of 'touched' does not exist there, the // touch-event will still be recorded in the journal. Since ripeMD is a special snowflake, // it will persist in the journal even though the journal is reverted. In this special circumstance, // it may exist in `db.journal.dirties` but not in `db.stateObjects`. // Thus, we can safely ignore it here continue } if stateObject.suicided || (deleteEmptyObjects && stateObject.empty()) { db.deleteStateObject(stateObject) } else { stateObject.updateRoot(db.db) db.updateStateObject(stateObject) } db.stateObjectsDirty[addr] = struct{}{} } // Invalidate journal because reverting across transactions is not allowed. db.clearJournalAndRefund() } // 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 (db *DB) IntermediateRoot(deleteEmptyObjects bool) common.Hash { db.Finalise(deleteEmptyObjects) return db.trie.Hash() } // Prepare sets the current transaction hash and index and block hash which is // used when the EVM emits new state logs. func (db *DB) Prepare(thash, bhash common.Hash, ti int) { db.thash = thash db.bhash = bhash db.txIndex = ti } func (db *DB) clearJournalAndRefund() { db.journal = newJournal() db.validRevisions = db.validRevisions[:0] db.refund = 0 } // Commit writes the state to the underlying in-memory trie database. func (db *DB) Commit(deleteEmptyObjects bool) (root common.Hash, err error) { defer db.clearJournalAndRefund() for addr := range db.journal.dirties { db.stateObjectsDirty[addr] = struct{}{} } // Commit objects to the trie. for addr, stateObject := range db.stateObjects { _, isDirty := db.stateObjectsDirty[addr] switch { case stateObject.suicided || (isDirty && deleteEmptyObjects && stateObject.empty()): // If the object has been removed, don't bother syncing it // and just mark it for deletion in the trie. db.deleteStateObject(stateObject) case isDirty: // Write any contract code associated with the state object if stateObject.code != nil && stateObject.dirtyCode { db.db.TrieDB().InsertBlob(common.BytesToHash(stateObject.CodeHash()), stateObject.code) stateObject.dirtyCode = false } // Write any storage changes in the state object to its storage trie. if err := stateObject.CommitTrie(db.db); err != nil { return common.Hash{}, err } // Update the object in the main account trie. db.updateStateObject(stateObject) } delete(db.stateObjectsDirty, addr) } // Write trie changes. root, err = db.trie.Commit(func(leaf []byte, parent common.Hash) error { var account Account if err := rlp.DecodeBytes(leaf, &account); err != nil { return nil } if account.Root != emptyState { db.db.TrieDB().Reference(account.Root, parent) } code := common.BytesToHash(account.CodeHash) if code != emptyCode { db.db.TrieDB().Reference(code, parent) } return nil }) //log.Debug("Trie cache stats after commit", "misses", trie.CacheMisses(), "unloads", trie.CacheUnloads()) return root, err } // GetStakingInfo returns staking information of a given validator (including delegation info) func (db *DB) GetStakingInfo(addr common.Address) *stk.ValidatorWrapper { by := db.GetCode(addr) if len(by) == 0 { return nil } val := stk.ValidatorWrapper{} err := rlp.DecodeBytes(by, &val) if err != nil { fmt.Printf("GetStakingInfo unable to decode: %v\n", err) return nil } return &val } // UpdateStakingInfo update staking information of a given validator (including delegation info) func (db *DB) UpdateStakingInfo(addr common.Address, val *stk.ValidatorWrapper) error { if err := val.SanityCheck(); err != nil { return err } by, err := rlp.EncodeToBytes(val) if err != nil { return err } db.SetCode(addr, by) return nil } // SetValidatorFlag checks whether it is a validator object func (db *DB) SetValidatorFlag(addr common.Address) { db.SetState(addr, staking.IsValidatorKey, staking.IsValidator) } // UnsetValidatorFlag checks whether it is a validator object func (db *DB) UnsetValidatorFlag(addr common.Address) { db.SetState(addr, staking.IsValidatorKey, common.Hash{}) } // IsValidator checks whether it is a validator object func (db *DB) IsValidator(addr common.Address) bool { so := db.getStateObject(addr) if so == nil { return false } return so.IsValidator(db.db) } // AddReward distributes the reward to all the delegators based on stake percentage. func (db *DB) AddReward(snapshot *stk.ValidatorWrapper, reward *big.Int) error { rewardPool := big.NewInt(0).Set(reward) curValidator := db.GetStakingInfo(snapshot.Validator.Address) if curValidator == nil { return errors.New("failed to distribute rewards: validator does not exist") } // Payout commission commissionInt := snapshot.Validator.CommissionRates.Rate.MulInt(reward).RoundInt() curValidator.Delegations[0].Reward.Add(curValidator.Delegations[0].Reward, commissionInt) rewardPool.Sub(rewardPool, commissionInt) totalRewardForDelegators := big.NewInt(0).Set(rewardPool) // Payout each delegator's reward pro-rata totalDelegationDec := numeric.NewDecFromBigInt(snapshot.TotalDelegation()) for i := range snapshot.Delegations { delegation := snapshot.Delegations[i] percentage := numeric.NewDecFromBigInt(delegation.Amount).Quo(totalDelegationDec) // percentage = / rewardInt := percentage.MulInt(totalRewardForDelegators).RoundInt() curDelegation := curValidator.Delegations[i] curDelegation.Reward.Add(curDelegation.Reward, rewardInt) rewardPool.Sub(rewardPool, rewardInt) } // The last remaining bit belongs to the validator (remember the validator's self delegation is always at index 0) if rewardPool.Cmp(big.NewInt(0)) > 0 { curValidator.Delegations[0].Reward.Add(curValidator.Delegations[0].Reward, rewardPool) } return db.UpdateStakingInfo(curValidator.Validator.Address, curValidator) }