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 /*

  * Copyright (c) 2008-2012 Niels Provos, Nick Mathewson

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions

  * are met:

  * 1. Redistributions of source code must retain the above copyright

  *    notice, this list of conditions and the following disclaimer.

  * 2. Redistributions in binary form must reproduce the above copyright

  *    notice, this list of conditions and the following disclaimer in the

  *    documentation and/or other materials provided with the distribution.

  * 3. The name of the author may not be used to endorse or promote products

  *    derived from this software without specific prior written permission.

  *

  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR

  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES

  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.

  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,

  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT

  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

  */

 #ifndef _EVTHREAD_INTERNAL_H_

 #define _EVTHREAD_INTERNAL_H_

 #ifdef __cplusplus

 extern "C" {

 #endif

 #include "event2/thread.h"

 #include "event2/event-config.h"

 #include "util-internal.h"

 struct event_base;

 #ifndef WIN32

 /* On Windows, the way we currently make DLLs, it's not allowed for us to

  * have shared global structures.  Thus, we only do the direct-call-to-function

  * code path if we know that the local shared library system supports it.

  */

 #define EVTHREAD_EXPOSE_STRUCTS

 #endif

 #if ! defined(_EVENT_DISABLE_THREAD_SUPPORT) && defined(EVTHREAD_EXPOSE_STRUCTS)

 /* Global function pointers to lock-related functions. NULL if locking isn't

    enabled. */

 extern struct evthread_lock_callbacks _evthread_lock_fns;

 extern struct evthread_condition_callbacks _evthread_cond_fns;

 extern unsigned long (*_evthread_id_fn)(void);

 extern int _evthread_lock_debugging_enabled;

 /** Return the ID of the current thread, or 1 if threading isn't enabled. */

 #define EVTHREAD_GET_ID() \

 	(_evthread_id_fn ? _evthread_id_fn() : 1)

 /** Return true iff we're in the thread that is currently (or most recently)

  * running a given event_base's loop. Requires lock. */

 #define EVBASE_IN_THREAD(base)				 \

 	(_evthread_id_fn == NULL ||			 \

 	(base)->th_owner_id == _evthread_id_fn())

 /** Return true iff we need to notify the base's main thread about changes to

  * its state, because it's currently running the main loop in another

  * thread. Requires lock. */

 #define EVBASE_NEED_NOTIFY(base)			 \

 	(_evthread_id_fn != NULL &&			 \

 	    (base)->running_loop &&			 \

 	    (base)->th_owner_id != _evthread_id_fn())

 /** Allocate a new lock, and store it in lockvar, a void*.  Sets lockvar to

     NULL if locking is not enabled. */

 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype)		\

 	((lockvar) = _evthread_lock_fns.alloc ?		\

 	    _evthread_lock_fns.alloc(locktype) : NULL)

 /** Free a given lock, if it is present and locking is enabled. */

 #define EVTHREAD_FREE_LOCK(lockvar, locktype)				\

 	do {								\

 		void *_lock_tmp_ = (lockvar);				\

 		if (_lock_tmp_ && _evthread_lock_fns.free)		\

 			_evthread_lock_fns.free(_lock_tmp_, (locktype)); \

 	} while (0)

 /** Acquire a lock. */

 #define EVLOCK_LOCK(lockvar,mode)					\

 	do {								\

 		if (lockvar)						\

 			_evthread_lock_fns.lock(mode, lockvar);		\

 	} while (0)

 /** Release a lock */

 #define EVLOCK_UNLOCK(lockvar,mode)					\

 	do {								\

 		if (lockvar)						\

 			_evthread_lock_fns.unlock(mode, lockvar);	\

 	} while (0)

 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */

 #define _EVLOCK_SORTLOCKS(lockvar1, lockvar2)				\

 	do {								\

 		if (lockvar1 && lockvar2 && lockvar1 > lockvar2) {	\

 			void *tmp = lockvar1;				\

 			lockvar1 = lockvar2;				\

 			lockvar2 = tmp;					\

 		}							\

 	} while (0)

 /** Lock an event_base, if it is set up for locking.  Acquires the lock

     in the base structure whose field is named 'lockvar'. */

 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do {				\

 		EVLOCK_LOCK((base)->lockvar, 0);			\

 	} while (0)

 /** Unlock an event_base, if it is set up for locking. */

 #define EVBASE_RELEASE_LOCK(base, lockvar) do {				\

 		EVLOCK_UNLOCK((base)->lockvar, 0);			\

 	} while (0)

 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is

  * locked and held by us. */

 #define EVLOCK_ASSERT_LOCKED(lock)					\

 	do {								\

 		if ((lock) && _evthread_lock_debugging_enabled) {	\

 			EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \

 		}							\

 	} while (0)

 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we

  * manage to get it. */

 static inline int EVLOCK_TRY_LOCK(void *lock);

 static inline int

 EVLOCK_TRY_LOCK(void *lock)

 {

 	if (lock && _evthread_lock_fns.lock) {

 		int r = _evthread_lock_fns.lock(EVTHREAD_TRY, lock);

 		return !r;

 	} else {

 		/* Locking is disabled either globally or for this thing;

 		 * of course we count as having the lock. */

 		return 1;

 	}

 }

 /** Allocate a new condition variable and store it in the void *, condvar */

 #define EVTHREAD_ALLOC_COND(condvar)					\

 	do {								\

 		(condvar) = _evthread_cond_fns.alloc_condition ?	\

 		    _evthread_cond_fns.alloc_condition(0) : NULL;	\

 	} while (0)

 /** Deallocate and free a condition variable in condvar */

 #define EVTHREAD_FREE_COND(cond)					\

 	do {								\

 		if (cond)						\

 			_evthread_cond_fns.free_condition((cond));	\

 	} while (0)

 /** Signal one thread waiting on cond */

 #define EVTHREAD_COND_SIGNAL(cond)					\

 	( (cond) ? _evthread_cond_fns.signal_condition((cond), 0) : 0 )

 /** Signal all threads waiting on cond */

 #define EVTHREAD_COND_BROADCAST(cond)					\

 	( (cond) ? _evthread_cond_fns.signal_condition((cond), 1) : 0 )

 /** Wait until the condition 'cond' is signalled.  Must be called while

  * holding 'lock'.  The lock will be released until the condition is

  * signalled, at which point it will be acquired again.  Returns 0 for

  * success, -1 for failure. */

 #define EVTHREAD_COND_WAIT(cond, lock)					\

 	( (cond) ? _evthread_cond_fns.wait_condition((cond), (lock), NULL) : 0 )

 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed.  Returns 1

  * on timeout. */

 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv)			\

 	( (cond) ? _evthread_cond_fns.wait_condition((cond), (lock), (tv)) : 0 )

 /** True iff locking functions have been configured. */

 #define EVTHREAD_LOCKING_ENABLED()		\

 	(_evthread_lock_fns.lock != NULL)

 #elif ! defined(_EVENT_DISABLE_THREAD_SUPPORT)

 unsigned long _evthreadimpl_get_id(void);

 int _evthreadimpl_is_lock_debugging_enabled(void);

 void *_evthreadimpl_lock_alloc(unsigned locktype);

 void _evthreadimpl_lock_free(void *lock, unsigned locktype);

 int _evthreadimpl_lock_lock(unsigned mode, void *lock);

 int _evthreadimpl_lock_unlock(unsigned mode, void *lock);

 void *_evthreadimpl_cond_alloc(unsigned condtype);

 void _evthreadimpl_cond_free(void *cond);

 int _evthreadimpl_cond_signal(void *cond, int broadcast);

 int _evthreadimpl_cond_wait(void *cond, void *lock, const struct timeval *tv);

 int _evthreadimpl_locking_enabled(void);

 #define EVTHREAD_GET_ID() _evthreadimpl_get_id()

 #define EVBASE_IN_THREAD(base)				\

 	((base)->th_owner_id == _evthreadimpl_get_id())

 #define EVBASE_NEED_NOTIFY(base)			 \

 	((base)->running_loop &&			 \

 	    ((base)->th_owner_id != _evthreadimpl_get_id()))

 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype)		\

 	((lockvar) = _evthreadimpl_lock_alloc(locktype))

 #define EVTHREAD_FREE_LOCK(lockvar, locktype)				\

 	do {								\

 		void *_lock_tmp_ = (lockvar);				\

 		if (_lock_tmp_)						\

 			_evthreadimpl_lock_free(_lock_tmp_, (locktype)); \

 	} while (0)

 /** Acquire a lock. */

 #define EVLOCK_LOCK(lockvar,mode)					\

 	do {								\

 		if (lockvar)						\

 			_evthreadimpl_lock_lock(mode, lockvar);		\

 	} while (0)

 /** Release a lock */

 #define EVLOCK_UNLOCK(lockvar,mode)					\

 	do {								\

 		if (lockvar)						\

 			_evthreadimpl_lock_unlock(mode, lockvar);	\

 	} while (0)

 /** Lock an event_base, if it is set up for locking.  Acquires the lock

     in the base structure whose field is named 'lockvar'. */

 #define EVBASE_ACQUIRE_LOCK(base, lockvar) do {				\

 		EVLOCK_LOCK((base)->lockvar, 0);			\

 	} while (0)

 /** Unlock an event_base, if it is set up for locking. */

 #define EVBASE_RELEASE_LOCK(base, lockvar) do {				\

 		EVLOCK_UNLOCK((base)->lockvar, 0);			\

 	} while (0)

 /** If lock debugging is enabled, and lock is non-null, assert that 'lock' is

  * locked and held by us. */

 #define EVLOCK_ASSERT_LOCKED(lock)					\

 	do {								\

 		if ((lock) && _evthreadimpl_is_lock_debugging_enabled()) { \

 			EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \

 		}							\

 	} while (0)

 /** Try to grab the lock for 'lockvar' without blocking, and return 1 if we

  * manage to get it. */

 static inline int EVLOCK_TRY_LOCK(void *lock);

 static inline int

 EVLOCK_TRY_LOCK(void *lock)

 {

 	if (lock) {

 		int r = _evthreadimpl_lock_lock(EVTHREAD_TRY, lock);

 		return !r;

 	} else {

 		/* Locking is disabled either globally or for this thing;

 		 * of course we count as having the lock. */

 		return 1;

 	}

 }

 /** Allocate a new condition variable and store it in the void *, condvar */

 #define EVTHREAD_ALLOC_COND(condvar)					\

 	do {								\

 		(condvar) = _evthreadimpl_cond_alloc(0);		\

 	} while (0)

 /** Deallocate and free a condition variable in condvar */

 #define EVTHREAD_FREE_COND(cond)					\

 	do {								\

 		if (cond)						\

 			_evthreadimpl_cond_free((cond));		\

 	} while (0)

 /** Signal one thread waiting on cond */

 #define EVTHREAD_COND_SIGNAL(cond)					\

 	( (cond) ? _evthreadimpl_cond_signal((cond), 0) : 0 )

 /** Signal all threads waiting on cond */

 #define EVTHREAD_COND_BROADCAST(cond)					\

 	( (cond) ? _evthreadimpl_cond_signal((cond), 1) : 0 )

 /** Wait until the condition 'cond' is signalled.  Must be called while

  * holding 'lock'.  The lock will be released until the condition is

  * signalled, at which point it will be acquired again.  Returns 0 for

  * success, -1 for failure. */

 #define EVTHREAD_COND_WAIT(cond, lock)					\

 	( (cond) ? _evthreadimpl_cond_wait((cond), (lock), NULL) : 0 )

 /** As EVTHREAD_COND_WAIT, but gives up after 'tv' has elapsed.  Returns 1

  * on timeout. */

 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, tv)			\

 	( (cond) ? _evthreadimpl_cond_wait((cond), (lock), (tv)) : 0 )

 #define EVTHREAD_LOCKING_ENABLED()		\

 	(_evthreadimpl_locking_enabled())

 #else /* _EVENT_DISABLE_THREAD_SUPPORT */

 #define EVTHREAD_GET_ID()	1

 #define EVTHREAD_ALLOC_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT

 #define EVTHREAD_FREE_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT

 #define EVLOCK_LOCK(lockvar, mode) _EVUTIL_NIL_STMT

 #define EVLOCK_UNLOCK(lockvar, mode) _EVUTIL_NIL_STMT

 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT

 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT

 #define EVBASE_IN_THREAD(base)	1

 #define EVBASE_NEED_NOTIFY(base) 0

 #define EVBASE_ACQUIRE_LOCK(base, lock) _EVUTIL_NIL_STMT

 #define EVBASE_RELEASE_LOCK(base, lock) _EVUTIL_NIL_STMT

 #define EVLOCK_ASSERT_LOCKED(lock) _EVUTIL_NIL_STMT

 #define EVLOCK_TRY_LOCK(lock) 1

 #define EVTHREAD_ALLOC_COND(condvar) _EVUTIL_NIL_STMT

 #define EVTHREAD_FREE_COND(cond) _EVUTIL_NIL_STMT

 #define EVTHREAD_COND_SIGNAL(cond) _EVUTIL_NIL_STMT

 #define EVTHREAD_COND_BROADCAST(cond) _EVUTIL_NIL_STMT

 #define EVTHREAD_COND_WAIT(cond, lock) _EVUTIL_NIL_STMT

 #define EVTHREAD_COND_WAIT_TIMED(cond, lock, howlong) _EVUTIL_NIL_STMT

 #define EVTHREAD_LOCKING_ENABLED() 0

 #endif

 /* This code is shared between both lock impls */

 #if ! defined(_EVENT_DISABLE_THREAD_SUPPORT)

 /** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */

 #define _EVLOCK_SORTLOCKS(lockvar1, lockvar2)				\

 	do {								\

 		if (lockvar1 && lockvar2 && lockvar1 > lockvar2) {	\

 			void *tmp = lockvar1;				\

 			lockvar1 = lockvar2;				\

 			lockvar2 = tmp;					\

 		}							\

 	} while (0)

 /** Acquire both lock1 and lock2.  Always allocates locks in the same order,

  * so that two threads locking two locks with LOCK2 will not deadlock. */

 #define EVLOCK_LOCK2(lock1,lock2,mode1,mode2)				\

 	do {								\

 		void *_lock1_tmplock = (lock1);				\

 		void *_lock2_tmplock = (lock2);				\

 		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\

 		EVLOCK_LOCK(_lock1_tmplock,mode1);			\

 		if (_lock2_tmplock != _lock1_tmplock)			\

 			EVLOCK_LOCK(_lock2_tmplock,mode2);		\

 	} while (0)

 /** Release both lock1 and lock2.  */

 #define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2)				\

 	do {								\

 		void *_lock1_tmplock = (lock1);				\

 		void *_lock2_tmplock = (lock2);				\

 		_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock);	\

 		if (_lock2_tmplock != _lock1_tmplock)			\

 			EVLOCK_UNLOCK(_lock2_tmplock,mode2);		\

 		EVLOCK_UNLOCK(_lock1_tmplock,mode1);			\

 	} while (0)

 int _evthread_is_debug_lock_held(void *lock);

 void *_evthread_debug_get_real_lock(void *lock);

 void *evthread_setup_global_lock_(void *lock_, unsigned locktype,

     int enable_locks);

 #define EVTHREAD_SETUP_GLOBAL_LOCK(lockvar, locktype)			\

 	do {								\

 		lockvar = evthread_setup_global_lock_(lockvar,		\

 		    (locktype), enable_locks);				\

 		if (!lockvar) {						\

 			event_warn("Couldn't allocate %s", #lockvar);	\

 			return -1;					\

 		}							\

 	} while (0);

 int event_global_setup_locks_(const int enable_locks);

 int evsig_global_setup_locks_(const int enable_locks);

 int evutil_secure_rng_global_setup_locks_(const int enable_locks);

 #endif

 #ifdef __cplusplus

 }

 #endif

 #endif /* _EVTHREAD_INTERNAL_H_ */