status-go/vendor/github.com/ethereum/go-ethereum/light/state.go

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// Copyright 2015 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 light
import (
"math/big"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/crypto"
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"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"golang.org/x/net/context"
)
// LightState is a memory representation of a state.
// This version is ODR capable, caching only the already accessed part of the
// state, retrieving unknown parts on-demand from the ODR backend. Changes are
// never stored in the local database, only in the memory objects.
type LightState struct {
odr OdrBackend
trie *LightTrie
id *TrieID
stateObjects map[string]*StateObject
refund *big.Int
}
// NewLightState creates a new LightState with the specified root.
// Note that the creation of a light state is always successful, even if the
// root is non-existent. In that case, ODR retrieval will always be unsuccessful
// and every operation will return with an error or wait for the context to be
// cancelled.
func NewLightState(id *TrieID, odr OdrBackend) *LightState {
var tr *LightTrie
if id != nil {
tr = NewLightTrie(id, odr, true)
}
return &LightState{
odr: odr,
trie: tr,
id: id,
stateObjects: make(map[string]*StateObject),
refund: new(big.Int),
}
}
// AddRefund adds an amount to the refund value collected during a vm execution
func (self *LightState) AddRefund(gas *big.Int) {
self.refund.Add(self.refund, gas)
}
// HasAccount returns true if an account exists at the given address
func (self *LightState) HasAccount(ctx context.Context, addr common.Address) (bool, error) {
so, err := self.GetStateObject(ctx, addr)
return so != nil, err
}
// GetBalance retrieves the balance from the given address or 0 if the account does
// not exist
func (self *LightState) GetBalance(ctx context.Context, addr common.Address) (*big.Int, error) {
stateObject, err := self.GetStateObject(ctx, addr)
if err != nil {
return common.Big0, err
}
if stateObject != nil {
return stateObject.balance, nil
}
return common.Big0, nil
}
// GetNonce returns the nonce at the given address or 0 if the account does
// not exist
func (self *LightState) GetNonce(ctx context.Context, addr common.Address) (uint64, error) {
stateObject, err := self.GetStateObject(ctx, addr)
if err != nil {
return 0, err
}
if stateObject != nil {
return stateObject.nonce, nil
}
return 0, nil
}
// GetCode returns the contract code at the given address or nil if the account
// does not exist
func (self *LightState) GetCode(ctx context.Context, addr common.Address) ([]byte, error) {
stateObject, err := self.GetStateObject(ctx, addr)
if err != nil {
return nil, err
}
if stateObject != nil {
return stateObject.code, nil
}
return nil, nil
}
// GetState returns the contract storage value at storage address b from the
// contract address a or common.Hash{} if the account does not exist
func (self *LightState) GetState(ctx context.Context, a common.Address, b common.Hash) (common.Hash, error) {
stateObject, err := self.GetStateObject(ctx, a)
if err == nil && stateObject != nil {
return stateObject.GetState(ctx, b)
}
return common.Hash{}, err
}
// HasSuicided returns true if the given account has been marked for deletion
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// or false if the account does not exist
func (self *LightState) HasSuicided(ctx context.Context, addr common.Address) (bool, error) {
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stateObject, err := self.GetStateObject(ctx, addr)
if err == nil && stateObject != nil {
return stateObject.remove, nil
}
return false, err
}
/*
* SETTERS
*/
// AddBalance adds the given amount to the balance of the specified account
func (self *LightState) AddBalance(ctx context.Context, addr common.Address, amount *big.Int) error {
stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.AddBalance(amount)
}
return err
}
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// SubBalance adds the given amount to the balance of the specified account
func (self *LightState) SubBalance(ctx context.Context, addr common.Address, amount *big.Int) error {
stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.SubBalance(amount)
}
return err
}
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// SetNonce sets the nonce of the specified account
func (self *LightState) SetNonce(ctx context.Context, addr common.Address, nonce uint64) error {
stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.SetNonce(nonce)
}
return err
}
// SetCode sets the contract code at the specified account
func (self *LightState) SetCode(ctx context.Context, addr common.Address, code []byte) error {
stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.SetCode(crypto.Keccak256Hash(code), code)
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}
return err
}
// SetState sets the storage value at storage address key of the account addr
func (self *LightState) SetState(ctx context.Context, addr common.Address, key common.Hash, value common.Hash) error {
stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.SetState(key, value)
}
return err
}
// Delete marks an account to be removed and clears its balance
func (self *LightState) Suicide(ctx context.Context, addr common.Address) (bool, error) {
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stateObject, err := self.GetOrNewStateObject(ctx, addr)
if err == nil && stateObject != nil {
stateObject.MarkForDeletion()
stateObject.balance = new(big.Int)
return true, nil
}
return false, err
}
//
// Get, set, new state object methods
//
// GetStateObject returns the state object of the given account or nil if the
// account does not exist
func (self *LightState) GetStateObject(ctx context.Context, addr common.Address) (stateObject *StateObject, err error) {
stateObject = self.stateObjects[addr.Str()]
if stateObject != nil {
if stateObject.deleted {
stateObject = nil
}
return stateObject, nil
}
data, err := self.trie.Get(ctx, addr[:])
if err != nil {
return nil, err
}
if len(data) == 0 {
return nil, nil
}
stateObject, err = DecodeObject(ctx, self.id, addr, self.odr, []byte(data))
if err != nil {
return nil, err
}
self.SetStateObject(stateObject)
return stateObject, nil
}
// SetStateObject sets the state object of the given account
func (self *LightState) SetStateObject(object *StateObject) {
self.stateObjects[object.Address().Str()] = object
}
// GetOrNewStateObject returns the state object of the given account or creates a
// new one if the account does not exist
func (self *LightState) GetOrNewStateObject(ctx context.Context, addr common.Address) (*StateObject, error) {
stateObject, err := self.GetStateObject(ctx, addr)
if err == nil && (stateObject == nil || stateObject.deleted) {
stateObject, err = self.CreateStateObject(ctx, addr)
}
return stateObject, err
}
// newStateObject creates a state object whether it exists in the state or not
func (self *LightState) newStateObject(addr common.Address) *StateObject {
if glog.V(logger.Core) {
glog.Infof("(+) %x\n", addr)
}
stateObject := NewStateObject(addr, self.odr)
self.stateObjects[addr.Str()] = stateObject
return stateObject
}
// CreateStateObject creates creates a new state object and takes ownership.
// This is different from "NewStateObject"
func (self *LightState) CreateStateObject(ctx context.Context, addr common.Address) (*StateObject, error) {
// Get previous (if any)
so, err := self.GetStateObject(ctx, addr)
if err != nil {
return nil, err
}
// 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, nil
}
//
// Setting, copying of the state methods
//
// Copy creates a copy of the state
func (self *LightState) Copy() *LightState {
// ignore error - we assume state-to-be-copied always exists
state := NewLightState(nil, self.odr)
state.trie = self.trie
state.id = self.id
for k, stateObject := range self.stateObjects {
if stateObject.dirty {
state.stateObjects[k] = stateObject.Copy()
}
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}
state.refund.Set(self.refund)
return state
}
// Set copies the contents of the given state onto this state, overwriting
// its contents
func (self *LightState) Set(state *LightState) {
self.trie = state.trie
self.stateObjects = state.stateObjects
self.refund = state.refund
}
// GetRefund returns the refund value collected during a vm execution
func (self *LightState) GetRefund() *big.Int {
return self.refund
}