Implemented event bus.

src/Makefile

@@ -4,6 +4,7 @@ CORE_SOURCES := \
   vector2d.c \
   inputs.c \
   asset_manager.c \
+  event_bus.c \
   ecs.c \
   display.c \
   main.c

src/event_bus.c

@@ -0,0 +1,118 @@
+#include "event_bus.h"
+
+#include <stdlib.h>
+#include "linked_list.h"
+#include "memory_alloc.h"
+
+// Args : void *payload
+int create_event(event_t *event, va_list args)
+{
+    event->payload = va_arg(args, void *);
+
+    return EXIT_SUCCESS;
+}
+
+int destroy_event(event_t *event)
+{
+    free(event->payload);
+
+    return EXIT_SUCCESS;
+}
+
+// Args : callback_t callback
+int create_subscription(subscription_t *subscription, va_list args)
+{
+    subscription->callback = va_arg(args, callback_t);
+
+    return EXIT_SUCCESS;
+}
+
+// Args : size_t id, size_t max_history_size
+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->subscriptions, sizeof(subscription_t), (allocator_t)create_subscription, NULL);
+
+    if(linked_list_reserve(&topic->events, topic->max_history_size)) return EXIT_FAILURE;
+
+    return EXIT_SUCCESS;
+}
+
+int destroy_topic(topic_t *topic)
+{
+    if(linked_list_exit(&topic->events)) return EXIT_FAILURE;
+    if(linked_list_exit(&topic->subscriptions)) return EXIT_FAILURE;
+
+    return EXIT_SUCCESS;
+}
+
+int 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;
+}
+
+int event_bus_exit(event_bus_t *event_bus)
+{
+    if(linked_list_exit(&event_bus->topics)) return EXIT_FAILURE;
+
+    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;
+
+    return EXIT_SUCCESS;
+}
+
+// Args : 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);
+}
+
+int event_bus_remove_topic(event_bus_t *event_bus, size_t id)
+{
+    if(linked_list_remove_if(&event_bus->topics, condition_is_topic_id, id)) return EXIT_FAILURE;
+
+    return EXIT_SUCCESS;
+}
+
+// Args : void *payload
+static inline int action_execute_callback(elem_t *elem, va_list args)
+{
+    subscription_t *subscription = elem->data;
+
+    if(subscription->callback(va_arg(args, void *))) return EXIT_FAILURE;
+
+    return EXIT_SUCCESS;
+}
+
+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;
+
+    topic_t *topic = topic_elem->data;
+    if(!create_elem(&topic->events, payload)) return EXIT_FAILURE;
+
+    if(linked_list_for_each(&topic->subscriptions, action_execute_callback, payload)) return EXIT_FAILURE;
+
+    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;
+
+    topic_t *topic = topic_elem->data;
+    if(!create_elem(&topic->subscriptions, callback)) return EXIT_FAILURE;
+
+    return EXIT_SUCCESS;
+}

src/headers/event_bus.h

@@ -0,0 +1,45 @@
+#ifndef EVENT_BUS_H
+#define EVENT_BUS_H
+
+#include <stdarg.h>
+#include "linked_list.h"
+
+typedef int (*callback_t)(void *payload);
+
+typedef struct event_t {
+    void *payload;
+} event_t;
+
+int create_event(event_t *event, va_list args);
+int destroy_event(event_t *event);
+
+typedef struct subscription_t {
+    callback_t callback;
+} subscription_t;
+
+int create_subscription(subscription_t *subscription, va_list args);
+
+typedef struct topic_t {
+    size_t id;
+    linked_list_t events;
+    linked_list_t subscriptions;
+    size_t max_history_size;
+} topic_t;
+
+int create_topic(topic_t *topic, va_list args);
+int destroy_topic(topic_t *topic);
+
+typedef struct event_bus_t {
+    linked_list_t topics;
+} event_bus_t;
+
+int 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_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);
+
+#endif // EVENT_BUS_H