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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
/*
* Ceph - scalable distributed file system
*
* Copyright (C) 2004-2006 Sage Weil <sage@newdream.net>
*
* This is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2.1, as published by the Free Software
* Foundation. See file COPYING.
*
*/
#ifndef CEPH_COND_H
#define CEPH_COND_H
#include "common/Clock.h"
#include "include/Context.h"
class Cond {
// my bits
pthread_cond_t _c;
Mutex *waiter_mutex;
// don't allow copying.
void operator=(Cond &C);
Cond(const Cond &C);
public:
Cond() : waiter_mutex(NULL) {
int r = pthread_cond_init(&_c,NULL);
ceph_assert(r == 0);
}
virtual ~Cond() {
pthread_cond_destroy(&_c);
}
int Wait(Mutex &mutex) {
// make sure this cond is used with one mutex only
ceph_assert(waiter_mutex == NULL || waiter_mutex == &mutex);
waiter_mutex = &mutex;
ceph_assert(mutex.is_locked());
mutex._pre_unlock();
int r = pthread_cond_wait(&_c, &mutex._m);
mutex._post_lock();
return r;
}
int WaitUntil(Mutex &mutex, utime_t when) {
// make sure this cond is used with one mutex only
ceph_assert(waiter_mutex == NULL || waiter_mutex == &mutex);
waiter_mutex = &mutex;
ceph_assert(mutex.is_locked());
struct timespec ts;
when.to_timespec(&ts);
mutex._pre_unlock();
int r = pthread_cond_timedwait(&_c, &mutex._m, &ts);
mutex._post_lock();
return r;
}
int WaitInterval(Mutex &mutex, utime_t interval) {
utime_t when = ceph_clock_now();
when += interval;
return WaitUntil(mutex, when);
}
template<typename Duration>
int WaitInterval(Mutex &mutex, Duration interval) {
ceph::real_time when(ceph::real_clock::now());
when += interval;
struct timespec ts = ceph::real_clock::to_timespec(when);
mutex._pre_unlock();
int r = pthread_cond_timedwait(&_c, &mutex._m, &ts);
mutex._post_lock();
return r;
}
int SloppySignal() {
int r = pthread_cond_broadcast(&_c);
return r;
}
int Signal() {
// make sure signaler is holding the waiter's lock.
ceph_assert(waiter_mutex == NULL ||
waiter_mutex->is_locked());
int r = pthread_cond_broadcast(&_c);
return r;
}
int SignalOne() {
// make sure signaler is holding the waiter's lock.
ceph_assert(waiter_mutex == NULL ||
waiter_mutex->is_locked());
int r = pthread_cond_signal(&_c);
return r;
}
int SignalAll() {
// make sure signaler is holding the waiter's lock.
ceph_assert(waiter_mutex == NULL ||
waiter_mutex->is_locked());
int r = pthread_cond_broadcast(&_c);
return r;
}
};
/**
* context to signal a cond
*
* Generic context to signal a cond and store the return value. We
* assume the caller is holding the appropriate lock.
*/
class C_Cond : public Context {
Cond *cond; ///< Cond to signal
bool *done; ///< true if finish() has been called
int *rval; ///< return value
public:
C_Cond(Cond *c, bool *d, int *r) : cond(c), done(d), rval(r) {
*done = false;
}
void finish(int r) override {
*done = true;
*rval = r;
cond->Signal();
}
};
/**
* context to signal a cond, protected by a lock
*
* Generic context to signal a cond under a specific lock. We take the
* lock in the finish() callback, so the finish() caller must not
* already hold it.
*/
class C_SafeCond : public Context {
Mutex *lock; ///< Mutex to take
Cond *cond; ///< Cond to signal
bool *done; ///< true after finish() has been called
int *rval; ///< return value (optional)
public:
C_SafeCond(Mutex *l, Cond *c, bool *d, int *r=0) : lock(l), cond(c), done(d), rval(r) {
*done = false;
}
void finish(int r) override {
lock->lock();
if (rval)
*rval = r;
*done = true;
cond->Signal();
lock->unlock();
}
};
/**
* Context providing a simple wait() mechanism to wait for completion
*
* The context will not be deleted as part of complete and must live
* until wait() returns.
*/
class C_SaferCond : public Context {
Mutex lock; ///< Mutex to take
Cond cond; ///< Cond to signal
bool done; ///< true after finish() has been called
int rval; ///< return value
public:
C_SaferCond() : lock("C_SaferCond"), done(false), rval(0) {}
explicit C_SaferCond(const std::string &name) : lock(name), done(false), rval(0) {}
void finish(int r) override { complete(r); }
/// We overload complete in order to not delete the context
void complete(int r) override {
std::lock_guard l(lock);
done = true;
rval = r;
cond.Signal();
}
/// Returns rval once the Context is called
int wait() {
std::lock_guard l(lock);
while (!done)
cond.Wait(lock);
return rval;
}
/// Wait until the \c secs expires or \c complete() is called
int wait_for(double secs) {
utime_t interval;
interval.set_from_double(secs);
std::lock_guard l{lock};
if (done) {
return rval;
}
cond.WaitInterval(lock, interval);
return done ? rval : ETIMEDOUT;
}
};
#endif
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