// -*- 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;

  // don't allow copying.
  void operator=(Cond &C) {}
  Cond( const Cond &C ) {}

 public:
  Cond() {
    int r = pthread_cond_init(&_c,NULL);
    assert(r == 0);
  }
  virtual ~Cond() { 
    pthread_cond_destroy(&_c); 
  }

  int Wait(Mutex &mutex)  { 
    assert(mutex.is_locked());
    --mutex.nlock;
    int r = pthread_cond_wait(&_c, &mutex._m);
    ++mutex.nlock;
    return r;
  }

  int Wait(Mutex &mutex, char* s)  { 
    //cout << "Wait: " << s << endl;
    assert(mutex.is_locked());
    --mutex.nlock;
    int r = pthread_cond_wait(&_c, &mutex._m);
    ++mutex.nlock;
    return r;
  }

  int WaitUntil(Mutex &mutex, utime_t when) {
    assert(mutex.is_locked());
    struct timespec ts;
    when.to_timespec(&ts);
    --mutex.nlock;
    int r = pthread_cond_timedwait(&_c, &mutex._m, &ts);
    ++mutex.nlock;
    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 Signal() { 
    //int r = pthread_cond_signal(&_c);
    int r = pthread_cond_broadcast(&_c);
    return r;
  }
  int SignalOne() { 
    int r = pthread_cond_signal(&_c);
    return r;
  }
  int SignalAll() { 
    //int r = pthread_cond_signal(&_c);
    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
