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/*
This file is part of cpp-ethereum.
cpp-ethereum is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
cpp-ethereum 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file Account.h
* @author Gav Wood <i@gavwood.com>
* @date 2014
*/
#pragma once
#include <libdevcore/Common.h>
#include <libdevcore/RLP.h>
#include <libdevcore/TrieDB.h>
#include <libdevcore/SHA3.h>
namespace dev
{
namespace eth
{
/**
* Models the state of a single Ethereum account.
* Used to cache a portion of the full Ethereum state. State keeps a mapping of Address's to Accounts.
*
* Aside from storing the nonce and balance, the account may also be "dead" (where isAlive() returns false).
* This allows State to explicitly store the notion of a deleted account in it's cache. kill() can be used
* for this.
*
* For the account's storage, the class operates a cache. baseRoot() specifies the base state of the storage
* given as the Trie root to be looked up in the state database. Alterations beyond this base are specified
* in the overlay, stored in this class and retrieved with storageOverlay(). setStorage allows the overlay
* to be altered.
*
* The code handling explicitly supports a two-stage commit model needed for contract-creation. When creating
* a contract (running the initialisation code), the code of the account is considered empty. The attribute
* of emptiness can be retrieved with codeBearing(). After initialisation one must set the code accordingly;
* the code of the Account can be set with setCode(). To validate a setCode() call, this class records the
* state of being in contract-creation (and thus in a state where setCode may validly be called). It can be
* determined through isFreshCode().
*
* The code can be retrieved through code(), and its hash through codeHash(). codeHash() is only valid when
* the account is not in the contract-creation phase (i.e. when isFreshCode() returns false). This class
* supports populating code on-demand from the state database. To determine if the code has been prepopulated
* call codeCacheValid(). To populate the code, look it up with codeHash() and populate with noteCode().
*
* @todo: need to make a noteCodeCommitted().
*
* The constructor allows you to create an one of a number of "types" of accounts. The default constructor
* makes a dead account (this is ignored by State when writing out the Trie). Another three allow a basic
* or contract account to be specified along with an initial balance. The fina two allow either a basic or
* a contract account to be created with arbitrary values.
*/
class Account
{
public:
/// Type of account to create.
enum NewAccountType
{
/// Normal account.
NormalCreation,
/// Contract account - we place this object into the contract-creation state (and as such we
/// expect setCode(), but codeHash() won't work).
ContractConception
};
/// Changedness of account to create.
enum Changedness
{
/// Account starts as though it has been changed.
Changed,
/// Account starts as though it has not been changed.
Unchanged
};
/// Construct a dead Account.
Account() {}
/// Construct an alive Account, with given endowment, for either a normal (non-contract) account or for a
/// contract account in the
/// conception phase, where the code is not yet known.
Account(u256 _balance, NewAccountType _t, Changedness _c = Changed): m_isAlive(true), m_isUnchanged(_c == Unchanged), m_balance(_balance), m_codeHash(_t == NormalCreation ? EmptySHA3 : c_contractConceptionCodeHash) {}
/// Explicit constructor for wierd cases of construction of a normal account.
Account(u256 _nonce, u256 _balance, Changedness _c = Changed): m_isAlive(true), m_isUnchanged(_c == Unchanged), m_nonce(_nonce), m_balance(_balance) {}
/// Explicit constructor for wierd cases of construction or a contract account.
Account(u256 _nonce, u256 _balance, h256 _contractRoot, h256 _codeHash, Changedness _c): m_isAlive(true), m_isUnchanged(_c == Unchanged), m_nonce(_nonce), m_balance(_balance), m_storageRoot(_contractRoot), m_codeHash(_codeHash) { assert(_contractRoot); }
/// Kill this account. Useful for the suicide opcode. Following this call, isAlive() returns false.
void kill() { m_isAlive = false; m_storageOverlay.clear(); m_codeHash = EmptySHA3; m_storageRoot = EmptyTrie; m_balance = 0; m_nonce = 0; changed(); }
/// @returns true iff this object represents an account in the state. Returns false if this object
/// represents an account that should no longer exist in the trie (an account that never existed or was
/// suicided).
bool isAlive() const { return m_isAlive; }
/// @returns true if the account is unchanged from creation.
bool isDirty() const { return !m_isUnchanged; }
/// @returns the balance of this account. Can be altered in place.
u256& balance() { return m_balance; }
/// @returns the balance of this account.
u256 const& balance() const { return m_balance; }
/// Increments the balance of this account by the given amount. It's a bigint, so can be negative.
void addBalance(bigint _i) { if (!_i) return; m_balance = (u256)((bigint)m_balance + _i); changed(); }
/// @returns the nonce of the account. Can be altered in place.
u256& nonce() { return m_nonce; }
/// @returns the nonce of the account.
u256 const& nonce() const { return m_nonce; }
/// Increment the nonce of the account by one.
void incNonce() { m_nonce++; changed(); }
/// @returns the root of the trie (whose nodes are stored in the state db externally to this class)
/// which encodes the base-state of the account's storage (upon which the storage is overlaid).
h256 baseRoot() const { assert(m_storageRoot); return m_storageRoot; }
/// @returns the storage overlay as a simple hash map.
std::unordered_map<u256, u256> const& storageOverlay() const { return m_storageOverlay; }
/// Set a key/value pair in the account's storage. This actually goes into the overlay, for committing
/// to the trie later.
void setStorage(u256 _p, u256 _v) { m_storageOverlay[_p] = _v; changed(); }
/// @returns true if we are in the contract-conception state and setCode is valid to call.
bool isFreshCode() const { return m_codeHash == c_contractConceptionCodeHash; }
/// @returns true if we are either in the contract-conception state or if the account's code is not
/// empty.
bool codeBearing() const { return m_codeHash != EmptySHA3; }
/// @returns the hash of the account's code. Must only be called when isFreshCode() returns false.
h256 codeHash() const { assert(!isFreshCode()); return m_codeHash; }
/// Sets the code of the account. Must only be called when isFreshCode() returns true.
void setCode(bytes&& _code) { assert(isFreshCode()); m_codeCache = std::move(_code); changed(); }
/// @returns true if the account's code is available through code().
bool codeCacheValid() const { return m_codeHash == EmptySHA3 || m_codeHash == c_contractConceptionCodeHash || m_codeCache.size(); }
/// Specify to the object what the actual code is for the account. @a _code must have a SHA3 equal to
/// codeHash() and must only be called when isFreshCode() returns false.
void noteCode(bytesConstRef _code) { assert(sha3(_code) == m_codeHash); m_codeCache = _code.toBytes(); }
/// @returns the account's code. Must only be called when codeCacheValid returns true.
bytes const& code() const { assert(codeCacheValid()); return m_codeCache; }
private:
/// Note that we've altered the account.
void changed() { m_isUnchanged = false; }
/// Is this account existant? If not, it represents a deleted account.
bool m_isAlive = false;
/// True if we've not made any alteration to the account having been given it's properties directly.
bool m_isUnchanged = false;
/// Account's nonce.
u256 m_nonce = 0;
/// Account's balance.
u256 m_balance = 0;
/// The base storage root. Used with the state DB to give a base to the storage. m_storageOverlay is
/// overlaid on this and takes precedence for all values set.
h256 m_storageRoot = EmptyTrie;
/** If c_contractConceptionCodeHash then we're in the limbo where we're running the initialisation code.
* We expect a setCode() at some point later.
* If EmptySHA3, then m_code, which should be empty, is valid.
* If anything else, then m_code is valid iff it's not empty, otherwise, State::ensureCached() needs to
* be called with the correct args.
*/
h256 m_codeHash = EmptySHA3;
/// The map with is overlaid onto whatever storage is implied by the m_storageRoot in the trie.
std::unordered_map<u256, u256> m_storageOverlay;
/// The associated code for this account. The SHA3 of this should be equal to m_codeHash unless m_codeHash
/// equals c_contractConceptionCodeHash.
bytes m_codeCache;
/// Value for m_codeHash when this account is having its code determined.
static const h256 c_contractConceptionCodeHash;
};
}
}