light: implemented odr-capable trie and state structures

1 files changed, 267 insertions, 0 deletions

diff --git a/light/state_object.go b/light/state_object.go
new file mode 100644
index 000000000..7660c3883
--- /dev/null
+++ b/light/state_object.go
@@ -0,0 +1,267 @@
+// 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 light
+
+import (
+	"bytes"
+	"fmt"
+	"math/big"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/logger"
+	"github.com/ethereum/go-ethereum/logger/glog"
+	"github.com/ethereum/go-ethereum/rlp"
+	"golang.org/x/net/context"
+)
+
+var emptyCodeHash = crypto.Sha3(nil)
+
+// Code represents a contract code in binary form
+type Code []byte
+
+// String returns a string representation of the code
+func (self Code) String() string {
+	return string(self) //strings.Join(Disassemble(self), " ")
+}
+
+// Storage is a memory map cache of a contract storage
+type Storage map[string]common.Hash
+
+// String returns a string representation of the storage cache
+func (self Storage) String() (str string) {
+	for key, value := range self {
+		str += fmt.Sprintf("%X : %X\n", key, value)
+	}
+
+	return
+}
+
+// Copy copies the contents of a storage cache
+func (self Storage) Copy() Storage {
+	cpy := make(Storage)
+	for key, value := range self {
+		cpy[key] = value
+	}
+
+	return cpy
+}
+
+// StateObject is a memory representation of an account or contract and its storage.
+// This version is ODR capable, caching only the already accessed part of the
+// storage, retrieving unknown parts on-demand from the ODR backend. Changes are
+// never stored in the local database, only in the memory objects.
+type StateObject struct {
+	odr  OdrBackend
+	trie *LightTrie
+
+	// Address belonging to this account
+	address common.Address
+	// The balance of the account
+	balance *big.Int
+	// The nonce of the account
+	nonce uint64
+	// The code hash if code is present (i.e. a contract)
+	codeHash []byte
+	// The code for this account
+	code Code
+	// Temporarily initialisation code
+	initCode Code
+	// Cached storage (flushed when updated)
+	storage Storage
+
+	// Mark for deletion
+	// When an object is marked for deletion it will be delete from the trie
+	// during the "update" phase of the state transition
+	remove  bool
+	deleted bool
+	dirty   bool
+}
+
+// NewStateObject creates a new StateObject of the specified account address
+func NewStateObject(address common.Address, odr OdrBackend) *StateObject {
+	object := &StateObject{
+		odr:      odr,
+		address:  address,
+		balance:  new(big.Int),
+		dirty:    true,
+		codeHash: emptyCodeHash,
+		storage:  make(Storage),
+	}
+	object.trie = NewLightTrie(common.Hash{}, odr, true)
+	return object
+}
+
+// MarkForDeletion marks an account to be removed
+func (self *StateObject) MarkForDeletion() {
+	self.remove = true
+	self.dirty = true
+
+	if glog.V(logger.Core) {
+		glog.Infof("%x: #%d %v X\n", self.Address(), self.nonce, self.balance)
+	}
+}
+
+// getAddr gets the storage value at the given address from the trie
+func (c *StateObject) getAddr(ctx context.Context, addr common.Hash) (common.Hash, error) {
+	var ret []byte
+	val, err := c.trie.Get(ctx, addr[:])
+	if err != nil {
+		return common.Hash{}, err
+	}
+	rlp.DecodeBytes(val, &ret)
+	return common.BytesToHash(ret), nil
+}
+
+// Storage returns the storage cache object of the account
+func (self *StateObject) Storage() Storage {
+	return self.storage
+}
+
+// GetState returns the storage value at the given address from either the cache
+// or the trie
+func (self *StateObject) GetState(ctx context.Context, key common.Hash) (common.Hash, error) {
+	strkey := key.Str()
+	value, exists := self.storage[strkey]
+	if !exists {
+		var err error
+		value, err = self.getAddr(ctx, key)
+		if err != nil {
+			return common.Hash{}, err
+		}
+		if (value != common.Hash{}) {
+			self.storage[strkey] = value
+		}
+	}
+
+	return value, nil
+}
+
+// SetState sets the storage value at the given address
+func (self *StateObject) SetState(k, value common.Hash) {
+	self.storage[k.Str()] = value
+	self.dirty = true
+}
+
+// AddBalance adds the given amount to the account balance
+func (c *StateObject) AddBalance(amount *big.Int) {
+	c.SetBalance(new(big.Int).Add(c.balance, amount))
+
+	if glog.V(logger.Core) {
+		glog.Infof("%x: #%d %v (+ %v)\n", c.Address(), c.nonce, c.balance, amount)
+	}
+}
+
+// SubBalance subtracts the given amount from the account balance
+func (c *StateObject) SubBalance(amount *big.Int) {
+	c.SetBalance(new(big.Int).Sub(c.balance, amount))
+
+	if glog.V(logger.Core) {
+		glog.Infof("%x: #%d %v (- %v)\n", c.Address(), c.nonce, c.balance, amount)
+	}
+}
+
+// SetBalance sets the account balance to the given amount
+func (c *StateObject) SetBalance(amount *big.Int) {
+	c.balance = amount
+	c.dirty = true
+}
+
+// Copy creates a copy of the state object
+func (self *StateObject) Copy() *StateObject {
+	stateObject := NewStateObject(self.Address(), self.odr)
+	stateObject.balance.Set(self.balance)
+	stateObject.codeHash = common.CopyBytes(self.codeHash)
+	stateObject.nonce = self.nonce
+	stateObject.trie = self.trie
+	stateObject.code = common.CopyBytes(self.code)
+	stateObject.initCode = common.CopyBytes(self.initCode)
+	stateObject.storage = self.storage.Copy()
+	stateObject.remove = self.remove
+	stateObject.dirty = self.dirty
+	stateObject.deleted = self.deleted
+
+	return stateObject
+}
+
+//
+// Attribute accessors
+//
+
+// Balance returns the account balance
+func (self *StateObject) Balance() *big.Int {
+	return self.balance
+}
+
+// Address returns the address of the contract/account
+func (c *StateObject) Address() common.Address {
+	return c.address
+}
+
+// Code returns the contract code
+func (self *StateObject) Code() []byte {
+	return self.code
+}
+
+// SetCode sets the contract code
+func (self *StateObject) SetCode(code []byte) {
+	self.code = code
+	self.codeHash = crypto.Sha3(code)
+	self.dirty = true
+}
+
+// SetNonce sets the account nonce
+func (self *StateObject) SetNonce(nonce uint64) {
+	self.nonce = nonce
+	self.dirty = true
+}
+
+// Nonce returns the account nonce
+func (self *StateObject) Nonce() uint64 {
+	return self.nonce
+}
+
+// Encoding
+
+type extStateObject struct {
+	Nonce    uint64
+	Balance  *big.Int
+	Root     common.Hash
+	CodeHash []byte
+}
+
+// DecodeObject decodes an RLP-encoded state object.
+func DecodeObject(ctx context.Context, address common.Address, odr OdrBackend, data []byte) (*StateObject, error) {
+	var (
+		obj = &StateObject{address: address, odr: odr, storage: make(Storage)}
+		ext extStateObject
+		err error
+	)
+	if err = rlp.DecodeBytes(data, &ext); err != nil {
+		return nil, err
+	}
+	obj.trie = NewLightTrie(ext.Root, odr, true)
+	if !bytes.Equal(ext.CodeHash, emptyCodeHash) {
+		if obj.code, err = retrieveNodeData(ctx, obj.odr, common.BytesToHash(ext.CodeHash)); err != nil {
+			return nil, fmt.Errorf("can't find code for hash %x: %v", ext.CodeHash, err)
+		}
+	}
+	obj.nonce = ext.Nonce
+	obj.balance = ext.Balance
+	obj.codeHash = ext.CodeHash
+	return obj, nil
+}
\ No newline at end of file