Working event bus.

src/event_bus.c

@@ -3,8 +3,9 @@
 #include <stdlib.h>
 #include "linked_list.h"
 #include "memory_alloc.h"
+#include "errors.h"
 
-// Args : void *payload
+// Arg : void *payload
 int create_event(event_t *event, va_list args)
 {
     event->payload = va_arg(args, void *);
@@ -12,14 +13,7 @@ int create_event(event_t *event, va_list args)
     return EXIT_SUCCESS;
 }
 
-int destroy_event(event_t *event)
-{
-    free(event->payload);
-
-    return EXIT_SUCCESS;
-}
-
-// Args : callback_t callback
+// Arg : callback_t callback
 int create_subscription(subscription_t *subscription, va_list args)
 {
     subscription->callback = va_arg(args, callback_t);
@@ -33,7 +27,7 @@ int create_topic(topic_t *topic, va_list args)
     topic->id = va_arg(args, size_t);
     topic->max_history_size = va_arg(args, size_t);
 
-    linked_list_init(&topic->events, sizeof(event_t), (allocator_t)create_event, (deleter_t)destroy_event);
+    linked_list_init(&topic->events, sizeof(event_t), (allocator_t)create_event, NULL);
     linked_list_init(&topic->subscriptions, sizeof(subscription_t), (allocator_t)create_subscription, NULL);
 
     if(linked_list_reserve(&topic->events, topic->max_history_size)) return EXIT_FAILURE;
@@ -49,28 +43,32 @@ int destroy_topic(topic_t *topic)
     return EXIT_SUCCESS;
 }
 
-int event_bus_init(event_bus_t *event_bus)
+void event_bus_init(event_bus_t *event_bus)
 {
     linked_list_init(&event_bus->topics, sizeof(topic_t), (allocator_t)create_topic, (deleter_t)destroy_topic);
 
-    return EXIT_SUCCESS;
+    debug_printf("Initialized event bus.");
 }
 
 int event_bus_exit(event_bus_t *event_bus)
 {
     if(linked_list_exit(&event_bus->topics)) return EXIT_FAILURE;
 
+    debug_printf("Exited event bus.");
     return EXIT_SUCCESS;
 }
 
 int event_bus_new_topic(event_bus_t *event_bus, size_t id, size_t max_history_size)
 {
-    if(!create_elem(&event_bus->topics, id, max_history_size)) return EXIT_FAILURE;
+    elem_t *topic_elem = create_elem(&event_bus->topics, id, max_history_size);
+    if(!topic_elem) return EXIT_FAILURE;
+
+    if(linked_list_push_back(&event_bus->topics, topic_elem)) return EXIT_FAILURE;
 
     return EXIT_SUCCESS;
 }
 
-// Args : size_t id
+// Arg : size_t id
 static inline bool condition_is_topic_id(elem_t *elem, va_list args)
 {
     return ((topic_t *)elem->data)->id == va_arg(args, size_t);
@@ -83,6 +81,21 @@ int event_bus_remove_topic(event_bus_t *event_bus, size_t id)
     return EXIT_SUCCESS;
 }
 
+int event_bus_change_topic_id(event_bus_t *event_bus, size_t old_id, size_t new_id)
+{
+    elem_t *topic_elem = linked_list_get_if(&event_bus->topics, condition_is_topic_id, old_id);
+    if(!topic_elem)
+    {
+        error_printf("No topics with id = %lu found.", old_id);
+        return EXIT_FAILURE;
+    }
+
+    topic_t *topic = topic_elem->data;
+    topic->id = new_id;
+
+    return EXIT_SUCCESS;
+}
+
 // Args : void *payload
 static inline int action_execute_callback(elem_t *elem, va_list args)
 {
@@ -96,23 +109,49 @@ static inline int action_execute_callback(elem_t *elem, va_list args)
 int event_bus_publish(event_bus_t *event_bus, size_t id, void *payload)
 {
     elem_t *topic_elem = linked_list_get_if(&event_bus->topics, condition_is_topic_id, id);
-    if(!topic_elem) return EXIT_FAILURE;
+    if(!topic_elem)
+    {
+        error_printf("No topics with id = %lu found.", id);
+        return EXIT_FAILURE;
+    }
 
     topic_t *topic = topic_elem->data;
-    if(!create_elem(&topic->events, payload)) return EXIT_FAILURE;
+
+    if(topic->events.size + 1 > topic->max_history_size)
+    {
+        elem_t *removed_event_elem = linked_list_pop_back(&topic->events);
+        if(!removed_event_elem) return EXIT_FAILURE;
+
+        destroy_elem(&topic->events, removed_event_elem);
+    }
+
+    elem_t *event_elem = create_elem(&topic->events, payload);
+    if(!event_elem) return EXIT_FAILURE;
+
+    if(linked_list_push_front(&topic->events, event_elem)) return EXIT_FAILURE;
 
     if(linked_list_for_each(&topic->subscriptions, action_execute_callback, payload)) return EXIT_FAILURE;
 
+    debug_printf("Event published, id = %lu, payload = %d", id, *(bool*)payload);
+
     return EXIT_SUCCESS;
 }
 
 int event_bus_subscribe(event_bus_t *event_bus, size_t id, callback_t callback)
 {
     elem_t *topic_elem = linked_list_get_if(&event_bus->topics, condition_is_topic_id, id);
-    if(!topic_elem) return EXIT_FAILURE;
+    if(!topic_elem)
+    {
+        error_printf("No topics with id = %lu found.", id);
+        return EXIT_FAILURE;
+    }
 
     topic_t *topic = topic_elem->data;
-    if(!create_elem(&topic->subscriptions, callback)) return EXIT_FAILURE;
+
+    elem_t *subscription_elem = create_elem(&topic->subscriptions, callback);
+    if(!subscription_elem) return EXIT_FAILURE;
+
+    if(linked_list_push_back(&topic->subscriptions, subscription_elem)) return EXIT_FAILURE;
 
     return EXIT_SUCCESS;
 }

src/headers/event_bus.h

@@ -11,7 +11,6 @@ typedef struct event_t {
 } event_t;
 
 int create_event(event_t *event, va_list args);
-int destroy_event(event_t *event);
 
 typedef struct subscription_t {
     callback_t callback;
@@ -33,11 +32,12 @@ typedef struct event_bus_t {
     linked_list_t topics;
 } event_bus_t;
 
-int event_bus_init(event_bus_t *event_bus);
+void event_bus_init(event_bus_t *event_bus);
 int event_bus_exit(event_bus_t *event_bus);
 
 int event_bus_new_topic(event_bus_t *event_bus, size_t id, size_t max_history_size);
 int event_bus_remove_topic(event_bus_t *event_bus, size_t id);
+int event_bus_change_topic_id(event_bus_t *event_bus, size_t old_id, size_t new_id);
 
 int event_bus_publish(event_bus_t *event_bus, size_t id, void *payload);
 int event_bus_subscribe(event_bus_t *event_bus, size_t id, callback_t callback);

src/headers/game.h

@@ -4,6 +4,7 @@
 #include <stdbool.h>
 #include "asset_manager.h"
 #include "ecs.h"
+#include "event_bus.h"
 #include "inputs.h"
 
 /**
@@ -19,6 +20,7 @@
 typedef struct game_t {
     asset_manager_t asset_manager;
     entity_manager_t entity_manager;
+    event_bus_t event_bus;
     inputs_t events;
 
     float delta_time_ms;

src/headers/linked_list.h

@@ -203,7 +203,7 @@ elem_t *linked_list_pop_back(linked_list_t *linked_list);
  *
  * @param linked_list   Pointer to a linked list
  *
- * @return EXIT_SUCCESS, EXIT_FAILURE on error.
+ * @return Pointer to element, NULL on error.
 */
 elem_t *linked_list_pop_front(linked_list_t *linked_list);