389-ds-base/include/base/crit.h

/** BEGIN COPYRIGHT BLOCK
 * Copyright (C) 2001 Sun Microsystems, Inc. Used by permission.
 * Copyright (C) 2005 Red Hat, Inc.
 * All rights reserved.
 *
 * License: GPL (version 3 or any later version).
 * See LICENSE for details.
 * END COPYRIGHT BLOCK **/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifndef BASE_CRIT_H
#define BASE_CRIT_H

#ifndef NOINTNSAPI
#define INTNSAPI
#endif /* !NOINTNSAPI */

/*
 * crit.h: Critical section abstraction. Used in threaded servers to protect
 *         areas where two threads can interfere with each other.
 *
 *         Condvars are condition variables that are used for thread-thread
 *         synchronization.
 *
 * Rob McCool
 */

#ifndef NETSITE_H
#include "netsite.h"
#endif /* !NETSITE_H */

/* Define C++ interface */
#ifdef __cplusplus

#include "prlog.h" /* NSPR */

#ifndef prmon_h___
#include "prmon.h"
#endif /* !prmon_h___ */

class NSAPI_PUBLIC CriticalSection
{
    public:
    CriticalSection();
    ~CriticalSection();
    void Acquire() { PR_EnterMonitor(_crtsec); }
    void Release() { PR_ExitMonitor(_crtsec); }

    private:
    PRMonitor *_crtsec;
};

inline CriticalSection::CriticalSection() : _crtsec(0)
{
    _crtsec = PR_NewMonitor();
    PR_ASSERT(_crtsec);
}

inline CriticalSection::~CriticalSection()
{
    if (_crtsec)
        PR_DestroyMonitor(_crtsec);
}

class SafeLock
{
    public:
    SafeLock(CriticalSection &);  // acquire lock
    ~SafeLock();                  // release lock
    private:
    CriticalSection &lock;
};

inline SafeLock::SafeLock(CriticalSection &_lock) : lock(_lock)
{
    lock.Acquire();
}

inline SafeLock::~SafeLock()
{
    lock.Release();
}
#endif /* __cplusplus */

/* --- Begin function prototypes --- */

#ifdef INTNSAPI

NSPR_BEGIN_EXTERN_C

/* ASSERT function only */
NSAPI_PUBLIC int crit_owner_is_me(CRITICAL id);

/*
 * INTcrit_init creates and returns a new critical section variable. At the
 * time of creation no one has entered it.
 */
NSAPI_PUBLIC CRITICAL INTcrit_init(void);

/*
 * INTcrit_enter enters a critical section. If someone is already in the
 * section, the calling thread is blocked until that thread exits.
 */
NSAPI_PUBLIC void INTcrit_enter(CRITICAL id);


/*
 * INTcrit_exit exits a critical section. If another thread is blocked waiting
 * to enter, it will be unblocked and given ownership of the section.
 */
NSAPI_PUBLIC void INTcrit_exit(CRITICAL id);


/*
 * INTcrit_terminate removes a previously allocated critical section variable.
 */
NSAPI_PUBLIC void INTcrit_terminate(CRITICAL id);


/*
 * INTcondvar_init initializes and returns a new condition variable. You
 * must provide a critical section to be associated with this condition
 * variable.
 */
NSAPI_PUBLIC CONDVAR INTcondvar_init(CRITICAL id);


/*
 * INTcondvar_wait blocks on the given condition variable. The calling thread
 * will be blocked until another thread calls INTcondvar_notify on this variable.
 * The caller must have entered the critical section associated with this
 * condition variable prior to waiting for it.
 */
NSAPI_PUBLIC void INTcondvar_wait(CONDVAR cv);
NSAPI_PUBLIC void condvar_timed_wait(CONDVAR _cv, long secs);


/*
 * INTcondvar_notify awakens any threads blocked on the given condition
 * variable. The caller must have entered the critical section associated
 * with this variable first.
 */
NSAPI_PUBLIC void INTcondvar_notify(CONDVAR cv);

/*
 * INTcondvar_notifyAll awakens all threads blocked on the given condition
 * variable. The caller must have entered the critical section associated
 * with this variable first.
 */
NSAPI_PUBLIC void INTcondvar_notifyAll(CONDVAR cv);

/*
 * INTcondvar_terminate frees the given previously allocated condition variable
 */
NSAPI_PUBLIC void INTcondvar_terminate(CONDVAR cv);


/*
 * Create a counting semaphore.
 * Return non-zero on success, 0 on failure.
 */
NSAPI_PUBLIC COUNTING_SEMAPHORE INTcs_init(int initial_count);

/*
 * Destroy a counting semaphore
 */
NSAPI_PUBLIC void INTcs_terminate(COUNTING_SEMAPHORE csp);

/*
 * Wait to "enter" the semaphore.
 * Return 0 on success, -1 on failure.
 */
NSAPI_PUBLIC int INTcs_wait(COUNTING_SEMAPHORE csp);

/*
 * Enter the semaphore if the count is > 0.  Otherwise return -1.
 *
 */
NSAPI_PUBLIC int INTcs_trywait(COUNTING_SEMAPHORE csp);

/*
 * Release the semaphore- allowing a thread to enter.
 * Return 0 on success, -1 on failure.
 */
NSAPI_PUBLIC int INTcs_release(COUNTING_SEMAPHORE csp);

NSPR_END_EXTERN_C

/* --- End function prototypes --- */

#define crit_init INTcrit_init
#define crit_enter INTcrit_enter
#define crit_exit INTcrit_exit
#define crit_terminate INTcrit_terminate
#define condvar_init INTcondvar_init
#define condvar_wait INTcondvar_wait
#define condvar_notify INTcondvar_notify
#define condvar_notifyAll INTcondvar_notifyAll
#define condvar_terminate INTcondvar_terminate
#define cs_init INTcs_init
#define cs_terminate INTcs_terminate
#define cs_wait INTcs_wait
#define cs_trywait INTcs_trywait
#define cs_release INTcs_release

#endif /* INTNSAPI */

#endif /* !BASE_CRIT_H */