mirror of
https://github.com/libevent/libevent.git
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186 lines
6.4 KiB
C
186 lines
6.4 KiB
C
/*
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* Copyright (c) 2008-2010 Niels Provos, Nick Mathewson
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _EVTHREAD_INTERNAL_H_
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#define _EVTHREAD_INTERNAL_H_
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <event2/thread.h>
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#include "event-config.h"
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#include "util-internal.h"
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struct event_base;
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#ifndef _EVENT_DISABLE_THREAD_SUPPORT
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/* Global function pointers to lock-related functions. NULL if locking isn't
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enabled. */
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extern struct evthread_lock_callbacks _evthread_lock_fns;
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extern unsigned long (*_evthread_id_fn)(void);
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extern int _evthread_lock_debugging_enabled;
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/** True iff the given event_base is set up to use locking */
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#define EVBASE_USING_LOCKS(base) \
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(base != NULL && (base)->th_base_lock != NULL)
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/** Return the ID of the current thread, or 1 if threading isn't enabled. */
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#define EVTHREAD_GET_ID() \
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(_evthread_id_fn ? _evthread_id_fn() : 1)
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/** Return true iff we're in the thread that is currently running a given
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* event_base's loop. */
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#define EVBASE_IN_THREAD(base) \
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(_evthread_id_fn == NULL || \
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(base)->th_owner_id == _evthread_id_fn())
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/** Allocate a new lock, and store it in lockvar, a void*. Sets lockvar to
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NULL if locking is not enabled. */
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#define EVTHREAD_ALLOC_LOCK(lockvar, locktype) \
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((lockvar) = _evthread_lock_fns.alloc ? \
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_evthread_lock_fns.alloc(locktype) : NULL)
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/** Free a given lock, if it is present and locking is enabled. */
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#define EVTHREAD_FREE_LOCK(lockvar, locktype) \
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do { \
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void *_lock_tmp_ = (lockvar); \
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if (_lock_tmp_ && _evthread_lock_fns.free) \
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_evthread_lock_fns.free(_lock_tmp_, (locktype)); \
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} while (0)
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/** Acquire a lock. */
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#define EVLOCK_LOCK(lockvar,mode) \
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do { \
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if (lockvar) \
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_evthread_lock_fns.lock(mode, lockvar); \
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} while (0)
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/** Release a lock */
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#define EVLOCK_UNLOCK(lockvar,mode) \
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do { \
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if (lockvar) \
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_evthread_lock_fns.unlock(mode, lockvar); \
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} while (0)
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/** Helper: put lockvar1 and lockvar2 into pointerwise ascending order. */
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#define _EVLOCK_SORTLOCKS(lockvar1, lockvar2) \
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do { \
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if (lockvar1 && lockvar2 && lockvar1 > lockvar2) { \
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void *tmp = lockvar1; \
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lockvar1 = lockvar2; \
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lockvar2 = tmp; \
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} \
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} while (0)
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/** Acquire both lock1 and lock2. Always allocates locks in the same order,
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* so that two threads locking two locks with LOCK2 will not deadlock. */
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#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) \
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do { \
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void *_lock1_tmplock = (lock1); \
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void *_lock2_tmplock = (lock2); \
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_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock); \
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EVLOCK_LOCK(_lock1_tmplock,mode1); \
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if (_lock2_tmplock != _lock1_tmplock) \
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EVLOCK_LOCK(_lock2_tmplock,mode2); \
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} while (0)
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/** Release both lock1 and lock2. */
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#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) \
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do { \
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void *_lock1_tmplock = (lock1); \
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void *_lock2_tmplock = (lock2); \
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_EVLOCK_SORTLOCKS(_lock1_tmplock,_lock2_tmplock); \
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if (_lock2_tmplock != _lock1_tmplock) \
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EVLOCK_UNLOCK(_lock2_tmplock,mode2); \
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EVLOCK_UNLOCK(_lock1_tmplock,mode1); \
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} while (0)
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/** Lock an event_base, if it is set up for locking. Acquires the lock
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in the base structure whose field is named 'lockvar'. */
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#define EVBASE_ACQUIRE_LOCK(base, lockvar) do { \
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if (EVBASE_USING_LOCKS(base)) \
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_evthread_lock_fns.lock(0, (base)->lockvar); \
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} while (0)
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/** Unlock an event_base, if it is set up for locking. */
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#define EVBASE_RELEASE_LOCK(base, lockvar) do { \
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if (EVBASE_USING_LOCKS(base)) \
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_evthread_lock_fns.unlock(0, (base)->lockvar); \
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} while (0)
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/** If lock debugging is enabled, and lock is non-null, assert that 'lock' is
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* locked and held by us. */
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#define EVLOCK_ASSERT_LOCKED(lock) \
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do { \
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if ((lock) && _evthread_lock_debugging_enabled) { \
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EVUTIL_ASSERT(_evthread_is_debug_lock_held(lock)); \
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} \
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} while (0)
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int _evthread_is_debug_lock_held(void *lock);
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/** Try to grab the lock for 'lockvar' without blocking, and return 1 if we
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* manage to get it. */
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static inline int EVLOCK_TRY_LOCK(void *lock);
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static inline int
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EVLOCK_TRY_LOCK(void *lock)
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{
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if (lock && _evthread_lock_fns.lock) {
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int r = _evthread_lock_fns.lock(EVTHREAD_TRY, lock);
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return !r;
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} else {
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/* Locking is disabled either globally or for this thing;
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* of course we count as having the lock. */
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return 1;
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}
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}
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#else /* _EVENT_DISABLE_THREAD_SUPPORT */
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#define EVTHREAD_GET_ID() 1
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#define EVTHREAD_ALLOC_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT
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#define EVTHREAD_FREE_LOCK(lockvar, locktype) _EVUTIL_NIL_STMT
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#define EVLOCK_LOCK(lockvar, mode) _EVUTIL_NIL_STMT
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#define EVLOCK_UNLOCK(lockvar, mode) _EVUTIL_NIL_STMT
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#define EVLOCK_LOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT
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#define EVLOCK_UNLOCK2(lock1,lock2,mode1,mode2) _EVUTIL_NIL_STMT
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#define EVBASE_IN_THREAD(base) 1
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#define EVBASE_ACQUIRE_LOCK(base, lock) _EVUTIL_NIL_STMT
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#define EVBASE_RELEASE_LOCK(base, lock) _EVUTIL_NIL_STMT
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#define EVLOCK_ASSERT_LOCKED(lock) _EVUTIL_NIL_STMT
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#define EVLOCK_TRY_LOCK(lock) 1
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* _EVTHREAD_INTERNAL_H_ */
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