MemoryDB.cpp

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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/>.
*/
#include "Common.h"
#include "MemoryDB.h"
using namespace std;
using namespace dev;

namespace dev
{

const char* DBChannel::name() { return "TDB"; }
const char* DBWarn::name() { return "TDB"; }

std::unordered_map<h256, std::string> MemoryDB::get() const
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        std::unordered_map<h256, std::string> ret;
        for (auto const& i: m_main)
                if (!m_enforceRefs || i.second.second > 0)
                        ret.insert(make_pair(i.first, i.second.first));
        return ret;
}

MemoryDB& MemoryDB::operator=(MemoryDB const& _c)
{
        if (this == &_c)
                return *this;
#if DEV_GUARDED_DB
        ReadGuard l(_c.x_this);
        WriteGuard l2(x_this);
#endif
        m_main = _c.m_main;
        m_aux = _c.m_aux;
        return *this;
}

std::string MemoryDB::lookup(h256 const& _h) const
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        auto it = m_main.find(_h);
        if (it != m_main.end())
        {
                if (!m_enforceRefs || it->second.second > 0)
                        return it->second.first;
                else
                        cwarn << "Lookup required for value with refcount == 0. This is probably a critical trie issue" << _h;
        }
        return std::string();
}

bool MemoryDB::exists(h256 const& _h) const
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        auto it = m_main.find(_h);
        if (it != m_main.end() && (!m_enforceRefs || it->second.second > 0))
                return true;
        return false;
}

void MemoryDB::insert(h256 const& _h, bytesConstRef _v)
{
#if DEV_GUARDED_DB
        WriteGuard l(x_this);
#endif
        auto it = m_main.find(_h);
        if (it != m_main.end())
        {
                it->second.first = _v.toString();
                it->second.second++;
        }
        else
                m_main[_h] = make_pair(_v.toString(), 1);
#if ETH_PARANOIA
        dbdebug << "INST" << _h << "=>" << m_main[_h].second;
#endif
}

bool MemoryDB::kill(h256 const& _h)
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        if (m_main.count(_h))
        {
                if (m_main[_h].second > 0)
                {
                        m_main[_h].second--;
                        return true;
                }
#if ETH_PARANOIA
                else
                {
                        // If we get to this point, then there was probably a node in the level DB which we need to remove and which we have previously
                        // used as part of the memory-based MemoryDB. Nothing to be worried about *as long as the node exists in the DB*.
                        dbdebug << "NOKILL-WAS" << _h;
                }
                dbdebug << "KILL" << _h << "=>" << m_main[_h].second;
        }
        else
        {
                dbdebug << "NOKILL" << _h;
#endif
        }
        return false;
}

bytes MemoryDB::lookupAux(h256 const& _h) const
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        auto it = m_aux.find(_h);
        if (it != m_aux.end() && (!m_enforceRefs || it->second.second))
                return it->second.first;
        return bytes();
}

void MemoryDB::removeAux(h256 const& _h)
{
#if DEV_GUARDED_DB
        WriteGuard l(x_this);
#endif
        m_aux[_h].second = false;
}

void MemoryDB::insertAux(h256 const& _h, bytesConstRef _v)
{
#if DEV_GUARDED_DB
        WriteGuard l(x_this);
#endif
        m_aux[_h] = make_pair(_v.toBytes(), true);
}

void MemoryDB::purge()
{
#if DEV_GUARDED_DB
        WriteGuard l(x_this);
#endif
        // purge m_main
        for (auto it = m_main.begin(); it != m_main.end(); )
                if (it->second.second)
                        ++it;
                else
                        it = m_main.erase(it);

        // purge m_aux
        for (auto it = m_aux.begin(); it != m_aux.end(); )
                if (it->second.second)
                        ++it;
                else
                        it = m_aux.erase(it);
}

h256Hash MemoryDB::keys() const
{
#if DEV_GUARDED_DB
        ReadGuard l(x_this);
#endif
        h256Hash ret;
        for (auto const& i: m_main)
                if (i.second.second)
                        ret.insert(i.first);
        return ret;
}

}