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Condition Variable makeover

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* Improved the Documentation
 * add an CONDITION_UNLOCK macro to exoplicitly unlock the condition mutex
 * Add ENSUREs to check that the mutex is locked
 * Fix the CONDITION_WAIT, takes the missing condition expression now
 * Fix, document and improve SIGNAL and BROADCAST macros
 * remove the signal and broadcast functions
This commit is contained in:
Christian Thaeter 2008-12-24 03:40:55 +01:00
parent c0bc3cffb7
commit 7e13ca33d5
1 changed files with 56 additions and 47 deletions
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103
src/lib/condition.h
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@ -39,6 +39,8 @@ 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) \
@ -55,24 +57,64 @@ LUMIERA_ERROR_DECLARE (CONDITION_DESTROY);
}); \
lumiera_condition_section_.condition; \
({ \
if (lumiera_condition_section_.condition) \
{ \
pthread_mutex_unlock (&lumiera_condition_section_.condition->mutex); \
lumiera_condition_section_.condition = NULL; \
RESOURCE_LEAVE(nobugflag, lumiera_condition_section_.rh); \
} \
LUMIERA_CONDITION_UNLOCK(nobugflag) \
}))
#define LUMIERA_CONDITION_WAIT \
/**
* 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; \
RESOURCE_LEAVE(nobugflag, 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 { \
NOBUG_RESOURCE_STATE_RAW (lumiera_condition_section_.flag, lumiera_condition_section_.rh, NOBUG_RESOURCEING); \
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 (0)
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))
#define LUMIERA_CONDITION_SIGNAL (nobugflag) pthread_cond_signal (&lumiera_condition_section_.condition->cond)
#define LUMIERA_CONDITION_BROADCAST (nobugflag) pthread_cond_broadcast (&lumiera_condition_section_.condition->cond)
/**
* 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)
@ -108,40 +150,6 @@ LumieraCondition
lumiera_condition_destroy (LumieraCondition self, struct nobug_flag* flag);
/**
* signal a single waiting thread.
* @param self condition variable to be signaled, must be given, all errors are fatal
*/
static inline void
lumiera_condition_signal (LumieraCondition self)
{
REQUIRE (self);
if (pthread_mutex_lock (&self->mutex))
LUMIERA_DIE (MUTEX_LOCK);
pthread_cond_signal (&self->cond);
if (pthread_mutex_unlock (&self->mutex))
LUMIERA_DIE (MUTEX_UNLOCK);
}
/**
* signal all waiting threads
* @param self condition variable to be signaled, must be given, all errors are fatal
*/
static inline void
lumiera_condition_broadcast (LumieraCondition self)
{
REQUIRE (self);
if (pthread_mutex_lock (&self->mutex))
LUMIERA_DIE (MUTEX_LOCK);
pthread_cond_broadcast (&self->cond);
if (pthread_mutex_unlock (&self->mutex))
LUMIERA_DIE (MUTEX_UNLOCK);
}
/**
* conditionacquirer used to manage the state of a condition variable.
*/
@ -154,6 +162,7 @@ struct lumiera_conditionacquirer_struct
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)