181 lines
7.4 KiB
C
181 lines
7.4 KiB
C
/*
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condition.h - condition variables
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Copyright (C) Lumiera.org
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2008, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef LUMIERA_CONDITION_H
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#define LUMIERA_CONDITION_H
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#include "lib/error.h"
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#include "lib/mutex.h"
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/**
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* @file
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* Condition variables, header
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*/
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LUMIERA_ERROR_DECLARE (CONDITION_DESTROY);
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/**
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* Condition section.
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* Locks the condition mutex, one can use LUMIERA_CONDITION_WAIT to wait for signals or
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* LUMIERA_CONDITION_SIGNAL or LUMIERA_CONDITION_BROADCAST to wake waiting threads
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* @param nobugflag NoBug flag used to log actions on the condition
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* @param cnd Condition variable to be locked
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*/
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#define LUMIERA_CONDITION_SECTION(nobugflag, cnd) \
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for (lumiera_conditionacquirer NOBUG_CLEANUP(lumiera_conditionacquirer_ensureunlocked) \
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lumiera_condition_section_ = {(LumieraCondition)1}; \
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lumiera_condition_section_.condition;) \
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for ( \
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({ \
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lumiera_condition_section_.condition = (cnd); \
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NOBUG_IF(NOBUG_MODE_ALPHA, lumiera_condition_section_.flag = &NOBUG_FLAG(nobugflag)); \
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NOBUG_RESOURCE_HANDLE_INIT (lumiera_condition_section_.rh); \
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RESOURCE_ENTER (nobugflag, (cnd)->rh, "acquire condition", &lumiera_condition_section_, \
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NOBUG_RESOURCE_EXCLUSIVE, lumiera_condition_section_.rh); \
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if (pthread_mutex_lock (&(cnd)->mutex)) LUMIERA_DIE (MUTEX_LOCK); \
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}); \
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lumiera_condition_section_.condition; \
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({ \
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LUMIERA_CONDITION_UNLOCK \
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}))
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/**
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* Explicit mutex unlock for a condition variable
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* One can early unlock the mutex of a condition variable prior leaving a CONDITION_SECTION.
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* The CONDITION_WAIT, CONDITION_SIGNAL and CONDITION_BROADCAST macros must not be used after the mutex
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* got unlocked.
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* @param nobugflag NoBug flag used to log actions on the condition
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*/
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#define LUMIERA_CONDITION_UNLOCK \
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if (lumiera_condition_section_.condition) \
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{ \
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pthread_mutex_unlock (&lumiera_condition_section_.condition->mutex); \
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lumiera_condition_section_.condition = NULL; \
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NOBUG_RESOURCE_LEAVE_RAW(lumiera_condition_section_.flag, lumiera_condition_section_.rh); \
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}
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/**
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* Wait for a condition.
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* Must be used inside a CONDITION_SECTION.
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* @param expr Conditon which must become true, else the condition variable goes back into sleep
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*/
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#define LUMIERA_CONDITION_WAIT(expr) \
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do { \
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ENSURE (lumiera_condition_section_.condition, "Condition mutex not locked"); \
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NOBUG_RESOURCE_STATE_RAW (lumiera_condition_section_.flag, lumiera_condition_section_.rh, NOBUG_RESOURCE_WAITING); \
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pthread_cond_wait (&lumiera_condition_section_.condition->cond, &lumiera_condition_section_.condition->mutex); \
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NOBUG_RESOURCE_STATE_RAW (lumiera_condition_section_.flag, lumiera_condition_section_.rh, NOBUG_RESOURCE_EXCLUSIVE);\
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} while (!(expr))
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/**
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* Signal a condition variable
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* Must be used inside a CONDITION_SECTION.
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* Wakes one thread waiting on the condition variable
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*/
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#define LUMIERA_CONDITION_SIGNAL \
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do { \
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ENSURE (lumiera_condition_section_.condition, "Condition mutex not locked"); \
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NOBUG_IF(NOBUG_MODE_ALPHA, TRACE(lumiera_condition_section_.flag, "Signaling")); \
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pthread_cond_signal (&lumiera_condition_section_.condition->cond); \
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} while (0)
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/**
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* Broadcast a condition variable
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* Must be used inside a CONDITION_SECTION.
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* Wakes all threads waiting on the condition variable
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*/
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#define LUMIERA_CONDITION_BROADCAST \
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do { \
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ENSURE (lumiera_condition_section_.condition, "Condition mutex not locked"); \
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NOBUG_IF(NOBUG_MODE_ALPHA, TRACE(lumiera_condition_section_.flag, "Broadcasting")); \
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pthread_cond_broadcast (&lumiera_condition_section_.condition->cond); \
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} while (0)
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/**
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* Condition variables.
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*
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*/
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struct lumiera_condition_struct
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{
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pthread_cond_t cond;
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pthread_mutex_t mutex;
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RESOURCE_HANDLE (rh);
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};
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typedef struct lumiera_condition_struct lumiera_condition;
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typedef lumiera_condition* LumieraCondition;
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/**
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* Initialize a condition variable
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* @param self is a pointer to the condition variable to be initialized
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* @return self as given
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*/
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LumieraCondition
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lumiera_condition_init (LumieraCondition self, const char* purpose, struct nobug_flag* flag);
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/**
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* Destroy a condition variable
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* @param self is a pointer to the condition variable to be destroyed
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* @return self as given
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*/
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LumieraCondition
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lumiera_condition_destroy (LumieraCondition self, struct nobug_flag* flag);
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/**
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* conditionacquirer used to manage the state of a condition variable.
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*/
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struct lumiera_conditionacquirer_struct
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{
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LumieraCondition condition;
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NOBUG_IF(NOBUG_MODE_ALPHA, struct nobug_flag* flag);
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RESOURCE_HANDLE (rh);
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};
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typedef struct lumiera_conditionacquirer_struct lumiera_conditionacquirer;
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typedef struct lumiera_conditionacquirer_struct* LumieraConditionacquirer;
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/* helper function for nobug */
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static inline void
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lumiera_conditionacquirer_ensureunlocked (LumieraConditionacquirer self)
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{
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ENSURE (!self->condition, "forgot to unlock condition variable");
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}
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#endif
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/*
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// Local Variables:
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// mode: C
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// c-file-style: "gnu"
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// indent-tabs-mode: nil
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// End:
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*/
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