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-rw-r--r--light/state.go275
1 files changed, 275 insertions, 0 deletions
diff --git a/light/state.go b/light/state.go
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index 000000000..e18f9cdc5
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+++ b/light/state.go
@@ -0,0 +1,275 @@
+// 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/logger"
+ "github.com/ethereum/go-ethereum/logger/glog"
+ "golang.org/x/net/context"
+)
+
+// StartingNonce determines the default nonce when new accounts are being created.
+var StartingNonce uint64
+
+// 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
+
+ stateObjects map[string]*StateObject
+}
+
+// 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(root common.Hash, odr OdrBackend) *LightState {
+ tr := NewLightTrie(root, odr, true)
+ return &LightState{
+ odr: odr,
+ trie: tr,
+ stateObjects: make(map[string]*StateObject),
+ }
+}
+
+// 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
+}
+
+// IsDeleted returns true if the given account has been marked for deletion
+// or false if the account does not exist
+func (self *LightState) IsDeleted(ctx context.Context, addr common.Address) (bool, error) {
+ 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
+}
+
+// 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(code)
+ }
+ 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) Delete(ctx context.Context, addr common.Address) (bool, error) {
+ 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, 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)
+ stateObject.SetNonce(StartingNonce)
+ 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(common.Hash{}, self.odr)
+ state.trie = self.trie
+ for k, stateObject := range self.stateObjects {
+ state.stateObjects[k] = stateObject.Copy()
+ }
+
+ 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
+}