path: root/core/state/statedb.go

// 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 <http://www.gnu.org/licenses/>.

// Package state provides a caching layer atop the Ethereum state trie.
package state

import (
    "fmt"
    "math/big"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/core/vm"
    "github.com/ethereum/go-ethereum/ethdb"
    "github.com/ethereum/go-ethereum/logger"
    "github.com/ethereum/go-ethereum/logger/glog"
    "github.com/ethereum/go-ethereum/rlp"
    "github.com/ethereum/go-ethereum/trie"
)

// The starting nonce determines the default nonce when new accounts are being
// created.
var StartingNonce uint64

// StateDBs 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 StateDB struct {
    db   ethdb.Database
    trie *trie.SecureTrie

    stateObjects map[string]*StateObject

    refund *big.Int

    thash, bhash common.Hash
    txIndex      int
    logs         map[common.Hash]vm.Logs
    logSize      uint

    reducedDao bool
}

// Create a new state from a given trie
func New(root common.Hash, db ethdb.Database) (*StateDB, error) {
    tr, err := trie.NewSecure(root, db)
    if err != nil {
        return nil, err
    }
    return &StateDB{
        db:           db,
        trie:         tr,
        stateObjects: make(map[string]*StateObject),
        refund:       new(big.Int),
        logs:         make(map[common.Hash]vm.Logs),
    }, nil
}

// Reset clears out all emphemeral state objects from the state db, but keeps
// the underlying state trie to avoid reloading data for the next operations.
func (self *StateDB) Reset(root common.Hash) error {
    var (
        err error
        tr  = self.trie
    )
    if self.trie.Hash() != root {
        if tr, err = trie.NewSecure(root, self.db); err != nil {
            return err
        }
    }
    *self = StateDB{
        db:           self.db,
        trie:         tr,
        stateObjects: make(map[string]*StateObject),
        refund:       new(big.Int),
        logs:         make(map[common.Hash]vm.Logs),
    }
    return nil
}

func (self *StateDB) StartRecord(thash, bhash common.Hash, ti int) {
    self.thash = thash
    self.bhash = bhash
    self.txIndex = ti
}

func (self *StateDB) AddLog(log *vm.Log) {
    log.TxHash = self.thash
    log.BlockHash = self.bhash
    log.TxIndex = uint(self.txIndex)
    log.Index = self.logSize
    self.logs[self.thash] = append(self.logs[self.thash], log)
    self.logSize++
}

func (self *StateDB) GetLogs(hash common.Hash) vm.Logs {
    return self.logs[hash]
}

func (self *StateDB) Logs() vm.Logs {
    var logs vm.Logs
    for _, lgs := range self.logs {
        logs = append(logs, lgs...)
    }
    return logs
}

func (self *StateDB) AddRefund(gas *big.Int) {
    self.refund.Add(self.refund, gas)
}

func (self *StateDB) HasAccount(addr common.Address) bool {
    return self.GetStateObject(addr) != nil
}

func (self *StateDB) Exist(addr common.Address) bool {
    return self.GetStateObject(addr) != nil
}

func (self *StateDB) GetAccount(addr common.Address) vm.Account {
    return self.GetStateObject(addr)
}

// Retrieve the balance from the given address or 0 if object not found
func (self *StateDB) GetBalance(addr common.Address) *big.Int {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        return stateObject.balance
    }

    return common.Big0
}

func (self *StateDB) GetNonce(addr common.Address) uint64 {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        return stateObject.nonce
    }

    return StartingNonce
}

func (self *StateDB) GetCode(addr common.Address) []byte {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        return stateObject.code
    }

    return nil
}

func (self *StateDB) GetCodeHash(addr common.Address) common.Hash {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        return common.BytesToHash(stateObject.codeHash)
    }
    return common.Hash{}
}

func (self *StateDB) GetState(a common.Address, b common.Hash) common.Hash {
    stateObject := self.GetStateObject(a)
    if stateObject != nil {
        return stateObject.GetState(b)
    }

    return common.Hash{}
}

func (self *StateDB) IsDeleted(addr common.Address) bool {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        return stateObject.remove
    }
    return false
}

/*
 * SETTERS
 */

func (self *StateDB) AddBalance(addr common.Address, amount *big.Int) {
    stateObject := self.GetOrNewStateObject(addr)
    if stateObject != nil {
        stateObject.AddBalance(amount)
    }
}

func (self *StateDB) SetNonce(addr common.Address, nonce uint64) {
    stateObject := self.GetOrNewStateObject(addr)
    if stateObject != nil {
        stateObject.SetNonce(nonce)
    }
}

func (self *StateDB) SetCode(addr common.Address, code []byte) {
    stateObject := self.GetOrNewStateObject(addr)
    if stateObject != nil {
        stateObject.SetCode(code)
    }
}

func (self *StateDB) SetState(addr common.Address, key common.Hash, value common.Hash) {
    stateObject := self.GetOrNewStateObject(addr)
    if stateObject != nil {
        stateObject.SetState(key, value)
    }
}

func (self *StateDB) Delete(addr common.Address) bool {
    stateObject := self.GetStateObject(addr)
    if stateObject != nil {
        stateObject.MarkForDeletion()
        stateObject.balance = new(big.Int)

        return true
    }

    return false
}

//
// Setting, updating & deleting state object methods
//

// Update the given state object and apply it to state trie
func (self *StateDB) UpdateStateObject(stateObject *StateObject) {
    addr := stateObject.Address()
    data, err := rlp.EncodeToBytes(stateObject)
    if err != nil {
        panic(fmt.Errorf("can't encode object at %x: %v", addr[:], err))
    }
    self.trie.Update(addr[:], data)
}

// Delete the given state object and delete it from the state trie
func (self *StateDB) DeleteStateObject(stateObject *StateObject) {
    stateObject.deleted = true

    addr := stateObject.Address()
    self.trie.Delete(addr[:])
    //delete(self.stateObjects, addr.Str())
}

// Retrieve a state object given my the address. Nil if not found
func (self *StateDB) GetStateObject(addr common.Address) (stateObject *StateObject) {
    stateObject = self.stateObjects[addr.Str()]
    if stateObject != nil {
        if stateObject.deleted {
            stateObject = nil
        }

        return stateObject
    }

    data := self.trie.Get(addr[:])
    if len(data) == 0 {
        return nil
    }
    stateObject, err := DecodeObject(addr, self.db, data)
    if err != nil {
        glog.Errorf("can't decode object at %x: %v", addr[:], err)
        return nil
    }
    self.SetStateObject(stateObject)
    return stateObject
}

func (self *StateDB) SetStateObject(object *StateObject) {
    self.stateObjects[object.Address().Str()] = object
}

// Retrieve a state object or create a new state object if nil
func (self *StateDB) GetOrNewStateObject(addr common.Address) *StateObject {
    stateObject := self.GetStateObject(addr)
    if stateObject == nil || stateObject.deleted {
        stateObject = self.CreateStateObject(addr)
    }

    return stateObject
}

// NewStateObject create a state object whether it exist in the trie or not
func (self *StateDB) newStateObject(addr common.Address) *StateObject {
    if glog.V(logger.Core) {
        glog.Infof("(+) %x\n", addr)
    }

    stateObject := NewStateObject(addr, self.db)
    stateObject.SetNonce(StartingNonce)
    self.stateObjects[addr.Str()] = stateObject

    return stateObject
}

// Creates creates a new state object and takes ownership. This is different from "NewStateObject"
func (self *StateDB) CreateStateObject(addr common.Address) *StateObject {
    // Get previous (if any)
    so := self.GetStateObject(addr)
    // Create a new one
    newSo := self.newStateObject(addr)

    // If it existed set the balance to the new account
    if so != nil {
        newSo.balance = so.balance
    }

    return newSo
}

func (self *StateDB) CreateAccount(addr common.Address) vm.Account {
    return self.CreateStateObject(addr)
}

//
// Setting, copying of the state methods
//

func (self *StateDB) Copy() *StateDB {
    // ignore error - we assume state-to-be-copied always exists
    state, _ := New(common.Hash{}, self.db)
    state.trie = self.trie
    for k, stateObject := range self.stateObjects {
        state.stateObjects[k] = stateObject.Copy()
    }

    state.refund.Set(self.refund)

    for hash, logs := range self.logs {
        state.logs[hash] = make(vm.Logs, len(logs))
        copy(state.logs[hash], logs)
    }
    state.logSize = self.logSize

    return state
}

func (self *StateDB) Set(state *StateDB) {
    self.trie = state.trie
    self.stateObjects = state.stateObjects

    self.refund = state.refund
    self.logs = state.logs
    self.logSize = state.logSize
}

func (self *StateDB) GetRefund() *big.Int {
    return self.refund
}

// 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 (s *StateDB) IntermediateRoot() common.Hash {
    s.refund = new(big.Int)
    for _, stateObject := range s.stateObjects {
        if stateObject.dirty {
            if stateObject.remove {
                s.DeleteStateObject(stateObject)
            } else {
                stateObject.Update()
                s.UpdateStateObject(stateObject)
            }
            stateObject.dirty = false
        }
    }
    return s.trie.Hash()
}

// DeleteSuicides flags the suicided objects for deletion so that it
// won't be referenced again when called / queried up on.
//
// DeleteSuicides should not be used for consensus related updates
// under any circumstances.
func (s *StateDB) DeleteSuicides() {
    // Reset refund so that any used-gas calculations can use
    // this method.
    s.refund = new(big.Int)
    for _, stateObject := range s.stateObjects {
        if stateObject.dirty {
            // If the object has been removed by a suicide
            // flag the object as deleted.
            if stateObject.remove {
                stateObject.deleted = true
            }
            stateObject.dirty = false
        }
    }
}

// Commit commits all state changes to the database.
func (s *StateDB) Commit() (root common.Hash, err error) {
    root, batch := s.CommitBatch()
    return root, batch.Write()
}

// CommitBatch commits all state changes to a write batch but does not
// execute the batch. It is used to validate state changes against
// the root hash stored in a block.
func (s *StateDB) CommitBatch() (root common.Hash, batch ethdb.Batch) {
    batch = s.db.NewBatch()
    root, _ = s.commit(batch)
    return root, batch
}

func (s *StateDB) commit(db trie.DatabaseWriter) (common.Hash, error) {
    s.refund = new(big.Int)

    for _, stateObject := range s.stateObjects {
        if stateObject.remove {
            // If the object has been removed, don't bother syncing it
            // and just mark it for deletion in the trie.
            s.DeleteStateObject(stateObject)
        } else {
            // Write any contract code associated with the state object
            if len(stateObject.code) > 0 {
                if err := db.Put(stateObject.codeHash, stateObject.code); err != nil {
                    return common.Hash{}, err
                }
            }
            // Write any storage changes in the state object to its trie.
            stateObject.Update()

            // Commit the trie of the object to the batch.
            // This updates the trie root internally, so
            // getting the root hash of the storage trie
            // through UpdateStateObject is fast.
            if _, err := stateObject.trie.CommitTo(db); err != nil {
                return common.Hash{}, err
            }
            // Update the object in the account trie.
            s.UpdateStateObject(stateObject)
        }
        stateObject.dirty = false
    }
    return s.trie.CommitTo(db)
}

func (self *StateDB) Refunds() *big.Int {
    return self.refund
}

// Debug stuff
func (self *StateDB) CreateOutputForDiff() {
    for _, stateObject := range self.stateObjects {
        stateObject.CreateOutputForDiff()
    }
}