/**********************************************************************
Looks for a cell with the given thread id. */
static
sync_cell_t*
sync_array_find_thread(
/*===================*/
/* out: pointer to cell or NULL
if not found */
sync_array_t* arr, /* in: wait array */
os_thread_id_t thread) /* in: thread id */
{
ulint i;
sync_cell_t* cell;
for (i = 0; i < arr->n_cells; i++) {
cell = sync_array_get_nth_cell(arr, i);
if (cell->wait_object != NULL
&& os_thread_eq(cell->thread, thread)) {
return(cell); /* Found */
}
}
return(NULL); /* Not found */
}
void
sync_array_wait_event(
/*==================*/
sync_array_t* arr, /* in: wait array */
ulint index) /* in: index of the reserved cell */
{
sync_cell_t* cell;
os_event_t event;
ut_a(arr);
sync_array_enter(arr);
cell = sync_array_get_nth_cell(arr, index);
ut_a(cell->wait_object);
ut_a(!cell->waiting);
ut_ad(os_thread_get_curr_id() == cell->thread);
if (cell->request_type == SYNC_MUTEX) {
event = ((mutex_t*) cell->wait_object)->event;
#ifdef __WIN__
/* On windows if the thread about to wait is the one which
has set the state of the rw_lock to RW_LOCK_WAIT_EX, then
it waits on a special event i.e.: wait_ex_event. */
} else if (cell->request_type == RW_LOCK_WAIT_EX) {
event = ((rw_lock_t*) cell->wait_object)->wait_ex_event;
#endif
} else {
event = ((rw_lock_t*) cell->wait_object)->event;
}
cell->waiting = TRUE;
#ifdef UNIV_SYNC_DEBUG
/* We use simple enter to the mutex below, because if
we cannot acquire it at once, mutex_enter would call
recursively sync_array routines, leading to trouble.
rw_lock_debug_mutex freezes the debug lists. */
rw_lock_debug_mutex_enter();
if (TRUE == sync_array_detect_deadlock(arr, cell, cell, 0)) {
fputs("########################################\n", stderr);
ut_error;
}
rw_lock_debug_mutex_exit();
#endif
sync_array_exit(arr);
os_event_wait_low(event, cell->signal_count);
sync_array_free_cell(arr, index);
}
sync_array_t*
sync_array_create(
/*==============*/
/* out, own: created wait array */
ulint n_cells, /* in: number of cells in the array
to create */
ulint protection) /* in: either SYNC_ARRAY_OS_MUTEX or
SYNC_ARRAY_MUTEX: determines the type
of mutex protecting the data structure */
{
sync_array_t* arr;
sync_cell_t* cell_array;
sync_cell_t* cell;
ulint i;
ut_a(n_cells > 0);
/* Allocate memory for the data structures */
arr = ut_malloc(sizeof(sync_array_t));
cell_array = ut_malloc(sizeof(sync_cell_t) * n_cells);
arr->n_cells = n_cells;
arr->n_reserved = 0;
arr->array = cell_array;
arr->protection = protection;
arr->sg_count = 0;
arr->res_count = 0;
/* Then create the mutex to protect the wait array complex */
if (protection == SYNC_ARRAY_OS_MUTEX) {
arr->os_mutex = os_mutex_create(NULL);
} else if (protection == SYNC_ARRAY_MUTEX) {
mutex_create(&arr->mutex, SYNC_NO_ORDER_CHECK);
} else {
ut_error;
}
for (i = 0; i < n_cells; i++) {
cell = sync_array_get_nth_cell(arr, i);
cell->wait_object = NULL;
cell->waiting = FALSE;
cell->signal_count = 0;
}
return(arr);
}
/******************************************************************//**
This function should be called when a thread starts to wait on
a wait array cell. In the debug version this function checks
if the wait for a semaphore will result in a deadlock, in which
case prints info and asserts. */
UNIV_INTERN
void
sync_array_wait_event(
/*==================*/
sync_array_t* arr, /*!< in: wait array */
ulint index) /*!< in: index of the reserved cell */
{
sync_cell_t* cell;
os_event_t event;
ut_a(arr);
sync_array_enter(arr);
cell = sync_array_get_nth_cell(arr, index);
ut_a(cell->wait_object);
ut_a(!cell->waiting);
ut_ad(os_thread_get_curr_id() == cell->thread);
event = sync_cell_get_event(cell);
cell->waiting = TRUE;
#ifdef UNIV_SYNC_DEBUG
/* We use simple enter to the mutex below, because if
we cannot acquire it at once, mutex_enter would call
recursively sync_array routines, leading to trouble.
rw_lock_debug_mutex freezes the debug lists. */
rw_lock_debug_mutex_enter();
if (TRUE == sync_array_detect_deadlock(arr, cell, cell, 0)) {
fputs("########################################\n", stderr);
ut_error;
}
rw_lock_debug_mutex_exit();
#endif
sync_array_exit(arr);
os_event_wait_low(event, cell->signal_count);
sync_array_free_cell(arr, index);
}
void
sync_array_validate(
/*================*/
sync_array_t* arr) /* in: sync wait array */
{
ulint i;
sync_cell_t* cell;
ulint count = 0;
sync_array_enter(arr);
for (i = 0; i < arr->n_cells; i++) {
cell = sync_array_get_nth_cell(arr, i);
if (cell->wait_object != NULL) {
count++;
}
}
ut_a(count == arr->n_reserved);
sync_array_exit(arr);
}
/******************************************************************//**
Reserves a wait array cell for waiting for an object.
The event of the cell is reset to nonsignalled state. */
UNIV_INTERN
void
sync_array_reserve_cell(
/*====================*/
sync_array_t* arr, /*!< in: wait array */
void* object, /*!< in: pointer to the object to wait for */
ulint type, /*!< in: lock request type */
const char* file, /*!< in: file where requested */
ulint line, /*!< in: line where requested */
ulint* index) /*!< out: index of the reserved cell */
{
sync_cell_t* cell;
os_event_t event;
ulint i;
ut_a(object);
ut_a(index);
sync_array_enter(arr);
arr->res_count++;
/* Reserve a new cell. */
for (i = 0; i < arr->n_cells; i++) {
cell = sync_array_get_nth_cell(arr, i);
if (cell->wait_object == NULL) {
cell->waiting = FALSE;
cell->wait_object = object;
if (type == SYNC_MUTEX) {
cell->old_wait_mutex = object;
} else {
cell->old_wait_rw_lock = object;
}
cell->request_type = type;
cell->file = file;
cell->line = line;
arr->n_reserved++;
*index = i;
sync_array_exit(arr);
/* Make sure the event is reset and also store
the value of signal_count at which the event
was reset. */
event = sync_cell_get_event(cell);
cell->signal_count = os_event_reset(event);
cell->reservation_time = time(NULL);
cell->thread = os_thread_get_curr_id();
return;
}
}
ut_error; /* No free cell found */
return;
}
