ecore: immediately block animator ticking upon receiving an exit signal

Summary:
when an exit (SIGINT, SIGQUIT, SIGTERM) signal is received, the ui should
immediately stop updating in order to present the user with an instant
response

this uses a simple volatile int to block any ticks which begin after the
signal is received; if a signal is received during a tick then it will complete
normally

fix T7000
Depends on D6589

Reviewers: ManMower

Reviewed By: ManMower

Subscribers: cedric, #committers

Tags: #efl_main_loop

Maniphest Tasks: T7000

Differential Revision: https://phab.enlightenment.org/D6590

src/lib/ecore/ecore_anim.c

@@ -110,6 +110,8 @@ static Eina_Spinlock tick_queue_lock;
 static int           tick_queue_count = 0;
 static Eina_Bool     tick_skip = EINA_FALSE;
 
+extern volatile int exit_signal_received;
+
 static void
 _tick_send(signed char val)
 {
@@ -367,7 +369,7 @@ _timer_tick_notify(void *data EINA_UNUSED, Ecore_Thread *thread EINA_UNUSED, voi
         if ((!tick_skip) || (tick_queued == 1))
           {
              ecore_loop_time_set(*t);
-             _do_tick();
+             if (!exit_signal_received) _do_tick();
              _ecore_animator_flush();
           }
         pt = *t;
@@ -935,7 +937,7 @@ ecore_animator_custom_tick(void)
 {
    EINA_MAIN_LOOP_CHECK_RETURN;
    if (src != ECORE_ANIMATOR_SOURCE_CUSTOM) return;
-   _do_tick();
+   if (!exit_signal_received) _do_tick();
    _ecore_animator_flush();
 }
 

src/lib/ecore/ecore_signal.c

@@ -39,6 +39,8 @@ static Eo *sig_pipe_handler = NULL;
 static Eina_Spinlock sig_pid_lock;
 static Eina_List *sig_pid_info_list = NULL;
 
+volatile int exit_signal_received = 0;
+
 typedef struct _Signal_Data
 {
    int sig;
@@ -171,6 +173,15 @@ _ecore_signal_callback(int sig, siginfo_t *si, void *foo EINA_UNUSED)
           }
         errno = err;
      }
+   switch (sig)
+     {
+      case SIGQUIT:
+      case SIGINT:
+      case SIGTERM:
+        exit_signal_received = 1;
+        break;
+      default: break;
+     }
 }
 
 static void
@@ -302,6 +313,7 @@ _ecore_signal_shutdown(void)
 # endif
    pthread_sigmask(SIG_BLOCK, &newset, NULL);
 #endif
+   exit_signal_received = 0;
 }
 
 void