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// **********************************************************************
//
// Copyright (c) 2003 - 2004
// ZeroC, Inc.
// North Palm Beach, FL, USA
//
// All Rights Reserved.
//
// This copy of Ice is licensed to you under the terms described in the
// ICE_LICENSE file included in this distribution.
//
// **********************************************************************
#ifndef ICE_UTIL_COND_H
#define ICE_UTIL_COND_H
#include <IceUtil/Config.h>
#include <IceUtil/Time.h>
#include <IceUtil/ThreadException.h>
#ifdef _WIN32
# include <IceUtil/Mutex.h>
#endif
namespace IceUtil
{
//
// Forward declaration (for friend declarations).
//
template <class T> class Monitor;
class RecMutex;
class Mutex;
#ifdef _WIN32
//
// Needed for implementation.
//
class Semaphore
{
public:
Semaphore(long = 0);
~Semaphore();
void wait() const;
bool timedWait(const Time&) const;
void post(int = 1) const;
private:
mutable HANDLE _sem;
};
#endif
//
// Condition variable implementation. Conforms to the same semantics
// as a POSIX threads condition variable.
//
class Cond : public noncopyable
{
public:
ICE_UTIL_API Cond();
ICE_UTIL_API ~Cond();
//
// signal restarts one of the threads that are waiting on the
// condition variable cond. If no threads are waiting on cond,
// nothing happens. If several threads are waiting on cond,
// exactly one is restarted, but it is not specified which.
//
ICE_UTIL_API void signal();
//
// broadcast restarts all the threads that are waiting on the
// condition variable cond. Nothing happens if no threads are
// waiting on cond.
//
ICE_UTIL_API void broadcast();
//
// MSVC doesn't support out-of-class definitions of member
// templates. See KB Article Q241949 for details.
//
//
// wait atomically unlocks the mutex and waits for the condition
// variable to be signaled. Before returning to the calling thread
// the mutex is reaquired.
//
template <typename Lock> inline void
wait(const Lock& lock) const
{
if(!lock.acquired())
{
throw ThreadLockedException(__FILE__, __LINE__);
}
waitImpl(lock._mutex);
}
//
// wait atomically unlocks the mutex and waits for the condition
// variable to be signaled for up to the given timeout. Before
// returning to the calling thread the mutex is reaquired. Returns
// true if the condition variable was signaled, false on a
// timeout.
//
template <typename Lock> inline bool
timedWait(const Lock& lock, const Time& timeout) const
{
if(!lock.acquired())
{
throw ThreadLockedException(__FILE__, __LINE__);
}
return timedWaitImpl(lock._mutex, timeout);
}
private:
friend class Monitor<Mutex>;
friend class Monitor<RecMutex>;
//
// The Monitor implementation uses waitImpl & timedWaitImpl.
//
#ifdef _WIN32
template <typename M> void
waitImpl(const M& mutex) const
{
preWait();
typedef typename M::LockState LockState;
LockState state;
mutex.unlock(state);
try
{
dowait();
mutex.lock(state);
}
catch(...)
{
mutex.lock(state);
throw;
}
}
template <typename M> bool
timedWaitImpl(const M& mutex, const Time& timeout) const
{
preWait();
typedef typename M::LockState LockState;
LockState state;
mutex.unlock(state);
try
{
bool rc = timedDowait(timeout);
mutex.lock(state);
return rc;
}
catch(...)
{
mutex.lock(state);
throw;
}
}
#else
template <typename M> void waitImpl(const M&) const;
template <typename M> bool timedWaitImpl(const M&, const Time&) const;
#endif
#ifdef _WIN32
ICE_UTIL_API void wake(bool);
ICE_UTIL_API void preWait() const;
ICE_UTIL_API void postWait(bool) const;
ICE_UTIL_API bool timedDowait(const Time&) const;
ICE_UTIL_API void dowait() const;
Mutex _internal;
Semaphore _gate;
Semaphore _queue;
mutable long _blocked;
mutable long _unblocked;
mutable long _toUnblock;
#else
mutable pthread_cond_t _cond;
#endif
};
#ifndef _WIN32
template <typename M> inline void
Cond::waitImpl(const M& mutex) const
{
typedef typename M::LockState LockState;
LockState state;
mutex.unlock(state);
int rc = pthread_cond_wait(&_cond, state.mutex);
mutex.lock(state);
if(rc != 0)
{
throw ThreadSyscallException(__FILE__, __LINE__, rc);
}
}
template <typename M> inline bool
Cond::timedWaitImpl(const M& mutex, const Time& timeout) const
{
typedef typename M::LockState LockState;
LockState state;
mutex.unlock(state);
timeval tv = Time::now() + timeout;
timespec ts;
ts.tv_sec = tv.tv_sec;
ts.tv_nsec = tv.tv_usec * 1000;
int rc = pthread_cond_timedwait(&_cond, state.mutex, &ts);
mutex.lock(state);
if(rc != 0)
{
//
// pthread_cond_timedwait returns ETIMEOUT in the event of a
// timeout.
//
if(rc != ETIMEDOUT)
{
throw ThreadSyscallException(__FILE__, __LINE__, rc);
}
return false;
}
return true;
}
#endif
} // End namespace IceUtil
#endif
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