Guards.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 <mutex>
#include <condition_variable>
#include <atomic>
#pragma warning(push)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#include <boost/thread.hpp>
#pragma warning(pop)
#pragma GCC diagnostic pop
 
namespace dev
{
 
using Mutex = std::mutex;
using RecursiveMutex = std::recursive_mutex;
using SharedMutex = boost::shared_mutex;
 
using Guard = std::lock_guard<std::mutex>;
using UniqueGuard = std::unique_lock<std::mutex>;
using RecursiveGuard = std::lock_guard<std::recursive_mutex>;
using ReadGuard = boost::shared_lock<boost::shared_mutex>;
using UpgradableGuard = boost::upgrade_lock<boost::shared_mutex>;
using UpgradeGuard = boost::upgrade_to_unique_lock<boost::shared_mutex>;
using WriteGuard = boost::unique_lock<boost::shared_mutex>;
 
template <class GuardType, class MutexType>
struct GenericGuardBool: GuardType
{
    GenericGuardBool(MutexType& _m): GuardType(_m) {}
    bool b = true;
};
template <class MutexType>
struct GenericUnguardBool
{
    GenericUnguardBool(MutexType& _m): m(_m) { m.unlock(); }
    ~GenericUnguardBool() { m.lock(); }
    bool b = true;
    MutexType& m;
};
template <class MutexType>
struct GenericUnguardSharedBool
{
    GenericUnguardSharedBool(MutexType& _m): m(_m) { m.unlock_shared(); }
    ~GenericUnguardSharedBool() { m.lock_shared(); }
    bool b = true;
    MutexType& m;
};
 
template <class N>
class Notified
{
public:
    Notified() {}
    Notified(N const& _v): m_value(_v) {}
    Notified(Notified const&) = delete;
    Notified& operator=(N const& _v) { UniqueGuard l(m_mutex); m_value = _v; m_cv.notify_all(); return *this; }
 
    operator N() const { UniqueGuard l(m_mutex); return m_value; }
 
    void wait() const { N old; { UniqueGuard l(m_mutex); old = m_value; } waitNot(old); }
    void wait(N const& _v) const { UniqueGuard l(m_mutex); m_cv.wait(l, [&](){return m_value == _v;}); }
    void waitNot(N const& _v) const { UniqueGuard l(m_mutex); m_cv.wait(l, [&](){return m_value != _v;}); }
    template <class F> void wait(F const& _f) const { UniqueGuard l(m_mutex); m_cv.wait(l, _f); }
 
    template <class R, class P> void wait(std::chrono::duration<R, P> _d) const { N old; { UniqueGuard l(m_mutex); old = m_value; } waitNot(_d, old); }
    template <class R, class P> void wait(std::chrono::duration<R, P> _d, N const& _v) const { UniqueGuard l(m_mutex); m_cv.wait_for(l, _d, [&](){return m_value == _v;}); }
    template <class R, class P> void waitNot(std::chrono::duration<R, P> _d, N const& _v) const { UniqueGuard l(m_mutex); m_cv.wait_for(l, _d, [&](){return m_value != _v;}); }
    template <class R, class P, class F> void wait(std::chrono::duration<R, P> _d, F const& _f) const { UniqueGuard l(m_mutex); m_cv.wait_for(l, _d, _f); }
 
private:
    mutable Mutex m_mutex;
    mutable std::condition_variable m_cv;
    N m_value;
};
 
#define DEV_GUARDED(MUTEX) \
    for (GenericGuardBool<Guard, Mutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_READ_GUARDED(MUTEX) \
    for (GenericGuardBool<ReadGuard, SharedMutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_WRITE_GUARDED(MUTEX) \
    for (GenericGuardBool<WriteGuard, SharedMutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_RECURSIVE_GUARDED(MUTEX) \
    for (GenericGuardBool<RecursiveGuard, RecursiveMutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_UNGUARDED(MUTEX) \
    for (GenericUnguardBool<Mutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_READ_UNGUARDED(MUTEX) \
    for (GenericUnguardSharedBool<SharedMutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
#define DEV_WRITE_UNGUARDED(MUTEX) \
    for (GenericUnguardBool<SharedMutex> __eth_l(MUTEX); __eth_l.b; __eth_l.b = false)
 
}