SealEngine.h

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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/>.
*/
#pragma once

#include <functional>
#include <unordered_map>
#include <libdevcore/Guards.h>
#include <libdevcore/RLP.h>
#include "BlockHeader.h"
#include "Common.h"

namespace dev
{
namespace eth
{

class BlockHeader;
struct ChainOperationParams;
class Interface;
class PrecompiledFace;
class TransactionBase;
class EnvInfo;

class SealEngineFace
{
public:
        virtual ~SealEngineFace() {}

        virtual std::string name() const = 0;
        virtual unsigned revision() const { return 0; }
        virtual unsigned sealFields() const { return 0; }
        virtual bytes sealRLP() const { return bytes(); }
        virtual StringHashMap jsInfo(BlockHeader const&) const { return StringHashMap(); }

        virtual void verify(Strictness _s, BlockHeader const& _bi, BlockHeader const& _parent = BlockHeader(), bytesConstRef _block = bytesConstRef()) const;
        virtual void verifyTransaction(ImportRequirements::value _ir, TransactionBase const& _t, BlockHeader const& _bi) const;
        virtual void populateFromParent(BlockHeader& _bi, BlockHeader const& _parent) const;

        bytes option(std::string const& _name) const { Guard l(x_options); return m_options.count(_name) ? m_options.at(_name) : bytes(); }
        bool setOption(std::string const& _name, bytes const& _value) { Guard l(x_options); try { if (onOptionChanging(_name, _value)) { m_options[_name] = _value; return true; } } catch (...) {} return false; }

        virtual strings sealers() const { return { "default" }; }
        virtual std::string sealer() const { return "default"; }
        virtual void setSealer(std::string const&) {}

        virtual bool shouldSeal(Interface*) { return true; }
        virtual void generateSeal(BlockHeader const& _bi) = 0;
        virtual void onSealGenerated(std::function<void(bytes const& s)> const& _f) = 0;
        virtual void cancelGeneration() {}

        ChainOperationParams const& chainParams() const { return m_params; }
        void setChainParams(ChainOperationParams const& _params) { m_params = _params; }
        SealEngineFace* withChainParams(ChainOperationParams const& _params) { setChainParams(_params); return this; }
        virtual EVMSchedule const& evmSchedule(EnvInfo const&) const = 0;

        virtual bool isPrecompiled(Address const& _a, u256 const& _blockNumber) const
        {
                return m_params.precompiled.count(_a) != 0 && _blockNumber >= m_params.precompiled.at(_a).startingBlock();
        }
        virtual bigint costOfPrecompiled(Address const& _a, bytesConstRef _in, u256 const&) const { return m_params.precompiled.at(_a).cost(_in); }
        virtual std::pair<bool, bytes> executePrecompiled(Address const& _a, bytesConstRef _in, u256 const&) const { return m_params.precompiled.at(_a).execute(_in); }

        void setFascSchedule(EVMSchedule _fascSchedule) const { fascSchedule = _fascSchedule; }

        EVMSchedule& getFascSchedule() const { return fascSchedule; }

        //deleteAddresses is a set that keeps track of accounts that were inserted as part of sending to pubkeyhash addresses
        //This is added to when doing a CALL to a non-existent address (if the account does not exist, it assumes you're sending to pubkeyhash)
        //It is also added to when a SUICIDE is done where all coins are sent to a non-existent address
        //After contract execution, these accounts will be deleted from the ETH database, and their vins marked dead, to ensure future executions behave the same
        mutable std::set<Address> deleteAddresses;

protected:
        virtual bool onOptionChanging(std::string const&, bytes const&) { return true; }

private:
        mutable Mutex x_options;
        std::unordered_map<std::string, bytes> m_options;

        mutable EVMSchedule fascSchedule; // fasc

        ChainOperationParams m_params;
};

class SealEngineBase: public SealEngineFace
{
public:
        void generateSeal(BlockHeader const& _bi) override
        {
                RLPStream ret;
                _bi.streamRLP(ret);
                if (m_onSealGenerated)
                        m_onSealGenerated(ret.out());
        }
        void onSealGenerated(std::function<void(bytes const&)> const& _f) override { m_onSealGenerated = _f; }
        EVMSchedule const& evmSchedule(EnvInfo const&) const override;

protected:
        std::function<void(bytes const& s)> m_onSealGenerated;
};

using SealEngineFactory = std::function<SealEngineFace*()>;

class SealEngineRegistrar
{
public:
        static SealEngineFace* create(ChainOperationParams const& _params);
        static SealEngineFace* create(std::string const& _name) { if (!get()->m_sealEngines.count(_name)) return nullptr; return get()->m_sealEngines[_name](); }

        template <class SealEngine> static SealEngineFactory registerSealEngine(std::string const& _name) { return (get()->m_sealEngines[_name] = [](){return new SealEngine;}); }
        static void unregisterSealEngine(std::string const& _name) { get()->m_sealEngines.erase(_name); }

private:
        static SealEngineRegistrar* get() { if (!s_this) s_this = new SealEngineRegistrar; return s_this; }

        std::unordered_map<std::string, SealEngineFactory> m_sealEngines;
        static SealEngineRegistrar* s_this;
};

#define ETH_REGISTER_SEAL_ENGINE(Name) static SealEngineFactory __eth_registerSealEngineFactory ## Name = SealEngineRegistrar::registerSealEngine<Name>(#Name)

class NoProof: public eth::SealEngineBase
{
public:
        std::string name() const override { return "NoProof"; }
        static void init();
};

}
}