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