/*

 * 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_INCLUDED_

#define EVTHREAD_INTERNAL_H_INCLUDED_

#ifdef __cplusplus

extern "C" {

#endif

#include "event2/event-config.h"

#include "evconfig-private.h"

#include "event2/thread.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. */

EVENT2_EXPORT_SYMBOL

extern struct evthread_lock_callbacks evthread_lock_fns_;

EVENT2_EXPORT_SYMBOL

extern struct evthread_condition_callbacks evthread_cond_fns_;

extern unsigned long (*evthread_id_fn_)(void);

EVENT2_EXPORT_SYMBOL

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;

  }

}

Unexecuted instantiation: event.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: evthread.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: evutil.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: evutil_rand.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: select.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: poll.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: epoll.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: signal.c:EVLOCK_TRY_LOCK_

Unexecuted instantiation: evdns.c:EVLOCK_TRY_LOCK_

/** 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);

EVENT2_EXPORT_SYMBOL

int evthreadimpl_is_lock_debugging_enabled_(void);

EVENT2_EXPORT_SYMBOL

void *evthreadimpl_lock_alloc_(unsigned locktype);

EVENT2_EXPORT_SYMBOL

void evthreadimpl_lock_free_(void *lock, unsigned locktype);

EVENT2_EXPORT_SYMBOL

int evthreadimpl_lock_lock_(unsigned mode, void *lock);

EVENT2_EXPORT_SYMBOL

int evthreadimpl_lock_unlock_(unsigned mode, void *lock);

EVENT2_EXPORT_SYMBOL

void *evthreadimpl_cond_alloc_(unsigned condtype);

EVENT2_EXPORT_SYMBOL

void evthreadimpl_cond_free_(void *cond);

EVENT2_EXPORT_SYMBOL

int evthreadimpl_cond_signal_(void *cond, int broadcast);

EVENT2_EXPORT_SYMBOL

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)

EVENT2_EXPORT_SYMBOL

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_global_setup_locks_(const int enable_locks);

int evutil_secure_rng_global_setup_locks_(const int enable_locks);

/** Return current evthread_lock_callbacks */

EVENT2_EXPORT_SYMBOL

struct evthread_lock_callbacks *evthread_get_lock_callbacks(void);

/** Return current evthread_condition_callbacks */

struct evthread_condition_callbacks *evthread_get_condition_callbacks(void);

/** Disable locking for internal usage (like global shutdown) */

void evthreadimpl_disable_lock_debugging_(void);

#endif

#ifdef __cplusplus

}

#endif

#endif /* EVTHREAD_INTERNAL_H_INCLUDED_ */