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/
evthread-internal.h
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/
evthread-internal.h
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/*
* Copyright (c) 2008-2010 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 "event-config.h"
#include "util-internal.h"
struct event_base;
#ifndef _EVENT_DISABLE_THREAD_SUPPORT
/* Global function pointers to lock-related functions. NULL if locking isn't
enabled. */
extern struct evthread_lock_callbacks _evthread_lock_fns;
extern unsigned long (*_evthread_id_fn)(void);
extern int _evthread_lock_debugging_enabled;
/** True iff the given event_base is set up to use locking */
#define EVBASE_USING_LOCKS(base) \
(base != NULL && (base)->th_base_lock != NULL)
/** 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 running a given
* event_base's loop. */
#define EVBASE_IN_THREAD(base) \
(_evthread_id_fn == NULL || \
(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)
/** 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)
/** 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 { \
if (EVBASE_USING_LOCKS(base)) \
_evthread_lock_fns.lock(0, (base)->lockvar); \
} while (0)
/** Unlock an event_base, if it is set up for locking. */
#define EVBASE_RELEASE_LOCK(base, lockvar) do { \
if (EVBASE_USING_LOCKS(base)) \
_evthread_lock_fns.unlock(0, (base)->lockvar); \
} 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)
int _evthread_is_debug_lock_held(void *lock);
/** 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;
}
}
#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_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
#endif
#ifdef __cplusplus
}
#endif
#endif /* _EVTHREAD_INTERNAL_H_ */