efl/legacy/evas/src/lib/cache/evas_preload.c

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#ifdef HAVE_EVIL
# include <Evil.h>
#endif

#ifdef BUILD_ASYNC_PRELOAD
# include <pthread.h>
#endif

#include "evas_common.h"
#include "evas_private.h"
#include "Evas.h"

static int _threads_max = 0;

#ifdef BUILD_ASYNC_PRELOAD

typedef struct _Evas_Preload_Pthread_Worker Evas_Preload_Pthread_Worker;
typedef struct _Evas_Preload_Pthread_Data Evas_Preload_Pthread_Data;

typedef void (*_evas_preload_pthread_func)(void *data);

struct _Evas_Preload_Pthread_Worker
{
   _evas_preload_pthread_func func_heavy;
   _evas_preload_pthread_func func_end;
   _evas_preload_pthread_func func_cancel;
   void *data;
   Eina_Bool cancel : 1;
};

struct _Evas_Preload_Pthread_Data
{
   pthread_t thread;
};

static int _threads_count = 0;
static Eina_List *_workers = NULL;

static LK(_mutex) = PTHREAD_MUTEX_INITIALIZER;

static void
_evas_preload_thread_end(void *data)
{
   Evas_Preload_Pthread_Data *pth = data;
   Evas_Preload_Pthread_Data *p = NULL;

   if (pthread_join(pth->thread, (void **)&p) != 0) free(p);
}

static void
_evas_preload_thread_done(void *target __UNUSED__, Evas_Callback_Type type __UNUSED__, void *event_info)
{
   Evas_Preload_Pthread_Worker *work = event_info;
   if (work->cancel)
     {
	if (work->func_cancel) work->func_cancel(work->data);
     }
   else
      work->func_end(work->data);
   free(work);
}

static void *
_evas_preload_thread_worker(void *data)
{
   Evas_Preload_Pthread_Data *pth = data;
   Evas_Preload_Pthread_Worker *work;
   
   pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
   pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, NULL);
on_error:
   for (;;)
     {
	LKL(_mutex);
	if (!_workers)
	  {
	     LKU(_mutex);
	     break;
	  }

	work = eina_list_data_get(_workers);
	_workers = eina_list_remove_list(_workers, _workers);
	LKU(_mutex);
        
	if (work->func_heavy) work->func_heavy(work->data);
	evas_async_events_put(pth, 0, work, _evas_preload_thread_done);
     }

   LKL(_mutex);
   if (_workers)
     {
	LKU(_mutex);
	goto on_error;
     }
   _threads_count--;
   LKU(_mutex);

   // dummy worker to wake things up
   work = malloc(sizeof(Evas_Preload_Pthread_Worker));
   if (!work) return NULL;

   work->data = pth;
   work->func_heavy = NULL;
   work->func_end = (_evas_preload_pthread_func) _evas_preload_thread_end;
   work->func_cancel = NULL;
   work->cancel = EINA_FALSE;

   evas_async_events_put(pth, 0, work, _evas_preload_thread_done);
   return pth;
}
#endif

void
_evas_preload_thread_init(void)
{
   _threads_max = eina_cpu_count();
   if (_threads_max < 1) _threads_max = 1;
}

void
_evas_preload_thread_shutdown(void)
{
   /* FIXME: If function are still running in the background, should we kill them ? */
#ifdef BUILD_ASYNC_PRELOAD
   Evas_Preload_Pthread_Worker *work;
   Evas_Preload_Pthread_Data *pth;

   /* Force processing of async events. */
   evas_async_events_process();
   LKL(_mutex);
   EINA_LIST_FREE(_workers, work)
     {
	if (work->func_cancel) work->func_cancel(work->data);
	free(work);
     }
   LKU(_mutex);
#endif
}

Evas_Preload_Pthread *
evas_preload_thread_run(void (*func_heavy) (void *data),
			void (*func_end) (void *data),
			void (*func_cancel) (void *data),
			const void *data)
{
#ifdef BUILD_ASYNC_PRELOAD
   Evas_Preload_Pthread_Worker *work;
   Evas_Preload_Pthread_Data *pth;

   work = malloc(sizeof(Evas_Preload_Pthread_Worker));
   if (!work)
     {
	func_cancel((void *)data);
	return NULL;
     }

   work->func_heavy = func_heavy;
   work->func_end = func_end;
   work->func_cancel = func_cancel;
   work->cancel = EINA_FALSE;
   work->data = (void *)data;

   LKL(_mutex);
   _workers = eina_list_append(_workers, work);
   if (_threads_count == _threads_max)
     {
	LKU(_mutex);
	return (Evas_Preload_Pthread *)work;
     }
   LKU(_mutex);

   /* One more thread could be created. */
   pth = malloc(sizeof(Evas_Preload_Pthread_Data));
   if (!pth) goto on_error;
   
   if (pthread_create(&pth->thread, NULL, _evas_preload_thread_worker, pth) == 0)
     {
#ifdef __linux__
        struct sched_param param;

        /* lower priority of async loader threads so they use up "bg cpu"
         * as it was really intended to work.
         * yes - this may fail if not root. there is no portable way to do
         * this so try - if it fails. meh. nothnig to be done.
         */
        memset(&param, 0, sizeof(param));
        param.sched_priority = sched_get_priority_max(SCHED_RR);
        if (pthread_setschedparam(pth->thread, SCHED_RR, &param) != 0)
          {
             int newp;

             errno = 0;
             newp = getpriority(PRIO_PROCESS, 0);
             if (errno == 0)
               {
                  newp += 5;
                  if (newp > 19) newp = 19;
                  setpriority(PRIO_PROCESS, pth->thread, newp);
               }
          }
#endif

	LKL(_mutex);
	_threads_count++;
	LKU(_mutex);
	return (Evas_Preload_Pthread*)work;
     }

 on_error:
   LKL(_mutex);
   if (_threads_count == 0)
     {
	LKU(_mutex);
	if (work->func_cancel) work->func_cancel(work->data);
	free(work);
     }
   LKU(_mutex);
   return NULL;
#else
   /*
    If no thread and as we don't want to break app that rely on this
    facility, we will lock the interface until we are done.
    */
   func_heavy((void *)data);
   func_end((void *)data);
   return (void *)1;
#endif
}

Eina_Bool
evas_preload_thread_cancel(Evas_Preload_Pthread *thread)
{
#ifdef BUILD_ASYNC_PRELOAD
   Evas_Preload_Pthread_Worker *work;
   Eina_List *l;

   if (!thread) return EINA_TRUE;
   LKL(_mutex);
   EINA_LIST_FOREACH(_workers, l, work)
     {
        if (work == (Evas_Preload_Pthread_Worker *)thread)
          {
             _workers = eina_list_remove_list(_workers, l);
             LKU(_mutex);
             if (work->func_cancel) work->func_cancel(work->data);
             free(work);
             return EINA_TRUE;
          }
     }
   LKU(_mutex);
   
   /* Delay the destruction */
   work = (Evas_Preload_Pthread_Worker *)thread;
   work->cancel = EINA_TRUE;
   return EINA_FALSE;
#else
   return EINA_TRUE;
#endif
}