Changeset c77cfd8 in mainline for uspace/app/taskbar/clock.c

Timestamp:

2022-10-04T19:55:25Z (3 years ago)

Author:

Jiri Svoboda <jiri@…>

Branches:

master, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

e0e612b

Parents:

3fd38b2

Message:

Proper timer cleanup, unit tests

Destroying a timer that sets itself again (i.e., runs periodically) is
a little tricky. It requires a handshake (similar to destroying a worker
thread). Realizing that this handshake works correctly is a little bit
mind boggling.

File:

• uspace/app/taskbar/clock.c (modified) (3 diffs)

uspace/app/taskbar/clock.c

@@ -89 +89 @@
         }
 
+        fibril_mutex_initialize(&clock->lock);
+        fibril_condvar_initialize(&clock->timer_done_cv);
         fibril_timer_set(clock->timer, 1000000, taskbar_clock_timer, clock);
 
@@ -106 +108 @@
 void taskbar_clock_destroy(taskbar_clock_t *clock)
 {
+        /*
+         * Signal to the timer that we are cleaning up. If the timer handler
+         * misses it and sets the timer again, we will clear that active
+         * timer and be done (and if we were even slower and the timer
+         * fired again, it's the same situation as before.
+         */
+        fibril_mutex_lock(&clock->lock);
+        clock->timer_cleanup = true;
+        fibril_mutex_unlock(&clock->lock);
+
+        /* If we catch the timer while it's active, there's nothing to do. */
+        if (fibril_timer_clear(clock->timer) != fts_active) {
+                /* Need to wait for timer handler to finish */
+                fibril_mutex_lock(&clock->lock);
+                while (clock->timer_done == false)
+                        fibril_condvar_wait(&clock->timer_done_cv, &clock->lock);
+                fibril_mutex_unlock(&clock->lock);
+        }
+
         fibril_timer_destroy(clock->timer);
         ui_control_delete(clock->control);
@@ -302 +323 @@
         taskbar_clock_t *clock = (taskbar_clock_t *) arg;
 
+        fibril_mutex_lock(&clock->lock);
         (void) taskbar_clock_paint(clock);
-        fibril_timer_set(clock->timer, 1000000, taskbar_clock_timer, clock);
+
+        if (!clock->timer_cleanup) {
+                fibril_timer_set(clock->timer, 1000000, taskbar_clock_timer,
+                    clock);
+        } else {
+                /* Acknowledge timer cleanup */
+                clock->timer_done = true;
+                fibril_condvar_signal(&clock->timer_done_cv);
+        }
+
+        fibril_mutex_unlock(&clock->lock);
 }