Fixed small corner cases dispatch logic

- Moved event id updates to deallocation. Dirty events are atomically
  updated directly to new ids instead of transitioning through a
  non-dirty state. This fixes behaviour when cancelling events after
  dispatch and avoids race conditions when cancelling in-flight events.

- Added semaphore signal to requeueing of period events. This avoids
  missing deadline updates from periodic events.

- Fixed fabricated range limitation in the posix equeue_sema_wait caused
  by using the equeue delay type for absolute time values.

Tests have been added for the above bugs where possible.

Author: geky

equeue.c

@@ -86,11 +86,6 @@ static struct equeue_event *equeue_mem_alloc(equeue_t *q, size_t size) {
                 *p = e->next;
             }
 
-            e->id += 1;
-            if (e->id >> (8*sizeof(int)-1 - q->npw2)) {
-                e->id = 1;
-            }
-
             equeue_mutex_unlock(&q->memlock);
             return e;
         }
@@ -240,6 +235,14 @@ static struct equeue_event *equeue_dequeue(equeue_t *q, int *deadline) {
     return head;
 }
 
+static inline int equeue_incid(equeue_t *q, int id) {
+    if ((id+1) >> (8*sizeof(int)-1 - q->npw2)) {
+        return 1;
+    }
+
+    return id+1;
+}
+
 int equeue_post(equeue_t *q, void (*cb)(void*), void *p) {
     struct equeue_event *e = (struct equeue_event*)p - 1;
     int id = (e->id << q->npw2) | ((unsigned char *)e - q->buffer);
@@ -274,6 +277,7 @@ void equeue_cancel(equeue_t *q, int id) {
     }
 
     equeue_unqueue(q, e);
+    e->id = equeue_incid(q, e->id);
     equeue_mutex_unlock(&q->queuelock);
 
     equeue_dealloc(q, e+1);
@@ -316,12 +320,15 @@ void equeue_dispatch(equeue_t *q, int ms) {
             }
 
             // undirty the id and either dealloc or reenqueue periodic events
-            e->id = -e->id;
             if (e->period >= 0) {
                 equeue_mutex_lock(&q->queuelock);
+                e->id = -e->id;
                 equeue_enqueue(q, e, e->period);
                 equeue_mutex_unlock(&q->queuelock);
+
+                equeue_sema_signal(&q->eventsema);
             } else {
+                e->id = equeue_incid(q, -e->id);
                 equeue_dealloc(q, e+1);
             }
         }

equeue_posix.c

@@ -12,6 +12,7 @@
 
 #include <time.h>
 #include <sys/time.h>
+#include <errno.h>
 
 
 // Tick operations
@@ -57,11 +58,14 @@ bool equeue_sema_wait(equeue_sema_t *s, int ms) {
     if (ms < 0) {
         return !sem_wait(s);
     } else {
-        ms += equeue_tick();
+        struct timeval tv;
+        gettimeofday(&tv, 0);
+
         struct timespec ts = {
-            .tv_sec = ms/1000,
-            .tv_nsec = ms*1000000,
+            .tv_sec = ms/1000 + tv.tv_sec,
+            .tv_nsec = ms*1000000 + tv.tv_usec*1000,
         };
+
         return !sem_timedwait(s, &ts);
     }
 }

tests/tests.c

@@ -43,7 +43,7 @@ void pass_func(void *eh) {
 }
 
 void simple_func(void *p) {
-    *(bool *)p = true;
+    (*(int *)p)++;
 }
 
 struct indirect {
@@ -113,10 +113,10 @@ void simple_call_in_test(void) {
     test_assert(!err);
 
     bool touched = false;
-    int id = equeue_call_in(&q, 5, simple_func, &touched);
+    int id = equeue_call_in(&q, 10, simple_func, &touched);
     test_assert(id);
 
-    equeue_dispatch(&q, 10);
+    equeue_dispatch(&q, 15);
     test_assert(touched);
 
     equeue_destroy(&q);
@@ -128,10 +128,10 @@ void simple_call_every_test(void) {
     test_assert(!err);
 
     bool touched = false;
-    int id = equeue_call_every(&q, 5, simple_func, &touched);
+    int id = equeue_call_every(&q, 10, simple_func, &touched);
     test_assert(id);
 
-    equeue_dispatch(&q, 10);
+    equeue_dispatch(&q, 15);
     test_assert(touched);
 
     equeue_destroy(&q);
@@ -227,6 +227,34 @@ void cancel_test(int N) {
     equeue_destroy(&q);
 }
 
+void cancel_unnecessarily_test(void) {
+    equeue_t q;
+    int err = equeue_create(&q, 2048);
+    test_assert(!err);
+
+    int id = equeue_call(&q, pass_func, 0);
+    for (int i = 0; i < 5; i++) {
+        equeue_cancel(&q, id);
+    }
+
+    id = equeue_call(&q, pass_func, 0);
+    equeue_dispatch(&q, 0);
+    for (int i = 0; i < 5; i++) {
+        equeue_cancel(&q, id);
+    }
+
+    bool touched = false;
+    equeue_call(&q, simple_func, &touched);
+    for (int i = 0; i < 5; i++) {
+        equeue_cancel(&q, id);
+    }
+
+    equeue_dispatch(&q, 0);
+    test_assert(touched);
+
+    equeue_destroy(&q);
+}
+
 void loop_protect_test(void) {
     equeue_t q;
     int err = equeue_create(&q, 2048);
@@ -262,6 +290,20 @@ void break_test(void) {
     equeue_destroy(&q);
 }
 
+void period_test(void) {
+    equeue_t q;
+    int err = equeue_create(&q, 2048);
+    test_assert(!err);
+
+    int count = 0;
+    equeue_call_every(&q, 10, simple_func, &count);
+
+    equeue_dispatch(&q, 55);
+    test_assert(count == 5);
+
+    equeue_destroy(&q);
+}
+
 // Barrage tests
 void simple_barrage_test(int N) {
     equeue_t q;
@@ -365,8 +407,10 @@ int main() {
     test_run(destructor_test);
     test_run(allocation_failure_test);
     test_run(cancel_test, 20);
+    test_run(cancel_unnecessarily_test);
     test_run(loop_protect_test);
     test_run(break_test);
+    test_run(period_test);
     test_run(simple_barrage_test, 20);
     test_run(fragmenting_barrage_test, 20);
     test_run(multithreaded_barrage_test, 20);