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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 <time.h>
#include "Mutex.h"
#include "Clock.h"
#include "include/Context.h"
#include <pthread.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);
assert(r == 0);
}
virtual ~Cond() {
pthread_cond_destroy(&_c);
}
int Wait(Mutex &mutex) {
// make sure this cond is used with one mutex only
assert(waiter_mutex == NULL || waiter_mutex == &mutex);
waiter_mutex = &mutex;
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
assert(waiter_mutex == NULL || waiter_mutex == &mutex);
waiter_mutex = &mutex;
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(CephContext *cct, Mutex &mutex, utime_t interval) {
utime_t when = ceph_clock_now(cct);
when += interval;
return WaitUntil(mutex, when);
}
int SloppySignal() {
int r = pthread_cond_broadcast(&_c);
return r;
}
int Signal() {
// make sure signaler is holding the waiter's lock.
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.
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.
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) {
*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) {
lock->Lock();
if (rval)
*rval = r;
*done = true;
cond->Signal();
lock->Unlock();
}
};
#endif
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