EFL Threading example 5

This is the same as EFL Threading example 4 but now uses the ecore_thread infrastructure to have a running worker thread that feeds results back to the mainloop and can easily be cancelled.

This saves some code in the application and makes for fewer problem spots if you forget a mutex.

EFL Threading example 6

//Compile with:
//gcc -o efl_thread_5 efl_thread_5.c -g `pkg-config --cflags --libs elementary`
#include <Elementary.h>

static Ecore_Thread *thr = NULL;

static Evas_Object *win = NULL;
static Evas_Object *rect = NULL;

struct info
{
   double x, y;
};

// BEGIN - code running in my custom thread instance
//
static void
th_do(void *data, Ecore_Thread *th)
{
   double t = 0.0;

   // inside our "do" function for the ecore thread, lets do the real work
   for (;;)
     {
        struct info *inf = malloc(sizeof(struct info));

        if (inf)
          {
             inf->x = 200 + (200 * sin(t));
             inf->y = 200 + (200 * cos(t));
             // now we have recorded the timepoint we pass it as feedback
             // back to the mainloop. it will free it when done
             ecore_thread_feedback(th, inf);
          }
        // and sleep and loop
        usleep(1000);
        t += 0.02;
        // in case someone has asked us to cancel - then cancel this loop
        // co-operatively (cancelling is co-operative)
        if (ecore_thread_check(th)) break;
     }
}
//
// END - code running in my custom thread instance

static void // when mainloop gets feedback from worker
th_feedback(void *data, Ecore_Thread *th, void *msg)
{
   struct info *inf = msg;
   evas_object_move(rect, inf->x - 50, inf->y - 50);
   free(inf);
}

// BONUS (optional): called after th_do returns and has NOT been cancelled
static void th_end(void *data, Ecore_Thread *th) { printf("thread ended\n"); }
// BONUS (optional): called in mainloop AFTER thread has finished cancelling
static void th_cancel(void *data, Ecore_Thread *th) { printf("thread cancelled\n"); }

// just test cancelling the thread worker
static void
down(void *data, Evas *e, Evas_Object *obj, void *event_info)
{
   if (thr) ecore_thread_cancel(thr);
   thr = NULL;
}

// on window delete - cancel thread then delete window and exit mainloop
static void
del(void *data, Evas_Object *obj, void *event_info)
{
   if (thr) ecore_thread_cancel(thr);
   thr = NULL;
   evas_object_del(obj);
   elm_exit();
}

EAPI_MAIN int
elm_main(int argc, char **argv)
{
   Evas_Object *o;

   elm_policy_set(ELM_POLICY_QUIT, ELM_POLICY_QUIT_LAST_WINDOW_CLOSED);

   win = elm_win_util_standard_add("efl-thread-5", "EFL Thread 5");
   evas_object_smart_callback_add(win, "delete,request", del, NULL);

   o = evas_object_rectangle_add(evas_object_evas_get(win));
   evas_object_color_set(o, 50, 80, 180, 255);
   evas_object_resize(o, 100, 100);
   evas_object_show(o);
   evas_object_event_callback_add(o, EVAS_CALLBACK_MOUSE_DOWN, down, NULL);
   rect = o;

   // explicitly create ecore thread to do some "work on the side" and pass
   // in NULL as data ptr to callbacks and true at the end means to actually
   // make a new thread and not use the thread pool (there is a thread pool
   // with as many thread workers as there are cpu's so this means you do not
   // overload the cpu's with more work than you actually have processing
   // units *IF* your threads do actually spend their time doing actual
   // heavy computation)
   thr = ecore_thread_feedback_run(th_do, th_feedback, th_end, th_cancel,
                                   NULL, EINA_TRUE);

   evas_object_resize(win, 400, 400);
   evas_object_show(win);

   elm_run();
   if (thr) ecore_thread_cancel(thr);

   return 0;
}
ELM_MAIN()