1 files changed, 128 insertions, 0 deletions
diff --git a/src/lib/notifier.c b/src/lib/notifier.c
new file mode 100644
index 00000000..cfd383d4
--- /dev/null
+++ b/src/lib/notifier.c
@@ -0,0 +1,128 @@
+/*
+ * Ouroboros - Copyright (C) 2016 - 2017
+ *
+ * Notifier event system using callbacks
+ *
+ *    Dimitri Staessens <dimitri.staessens@ugent.be>
+ *    Sander Vrijders   <sander.vrijders@ugent.be>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., http://www.fsf.org/about/contact/.
+ */
+
+#include <ouroboros/errno.h>
+#include <ouroboros/notifier.h>
+#include <ouroboros/list.h>
+
+#include <pthread.h>
+#include <stdlib.h>
+
+struct listener {
+        struct list_head next;
+        notifier_fn_t    callback;
+};
+
+struct {
+        struct list_head listeners;
+        pthread_mutex_t  lock;
+} notifier;
+
+int notifier_init(void)
+{
+        if (pthread_mutex_init(&notifier.lock, NULL))
+                return -1;
+
+        list_head_init(&notifier.listeners);
+
+        return 0;
+}
+
+void notifier_fini(void)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        pthread_mutex_lock(&notifier.lock);
+
+        list_for_each_safe(p, h, &notifier.listeners) {
+                struct listener * l = list_entry(p, struct listener, next);
+                list_del(&l->next);
+                free(l);
+        }
+
+        pthread_mutex_unlock(&notifier.lock);
+
+        pthread_mutex_destroy(&notifier.lock);
+}
+
+void notifier_event(int          event,
+                    const void * o)
+{
+        struct list_head * p;
+
+        pthread_mutex_lock(&notifier.lock);
+
+        list_for_each(p, &notifier.listeners)
+                list_entry(p, struct listener, next)->callback(event, o);
+
+        pthread_mutex_unlock(&notifier.lock);
+}
+
+int notifier_reg(notifier_fn_t callback)
+{
+        struct listener *  l;
+        struct list_head * p;
+
+        pthread_mutex_lock(&notifier.lock);
+
+        list_for_each(p, &notifier.listeners) {
+                struct listener * l = list_entry(p, struct listener, next);
+                if (l->callback == callback) {
+                        pthread_mutex_unlock(&notifier.lock);
+                        return -EPERM;
+                }
+        }
+
+        l = malloc(sizeof(*l));
+        if (l == NULL) {
+                pthread_mutex_unlock(&notifier.lock);
+                return -ENOMEM;
+        }
+
+        l->callback = callback;
+
+        list_add(&l->next, &notifier.listeners);
+
+        pthread_mutex_unlock(&notifier.lock);
+
+        return 0;
+}
+
+void notifier_unreg(notifier_fn_t callback)
+{
+        struct list_head * p;
+        struct list_head * h;
+
+        pthread_mutex_lock(&notifier.lock);
+
+        list_for_each_safe(p, h, &notifier.listeners) {
+                struct listener * l = list_entry(p, struct listener, next);
+                if (l->callback == callback) {
+                        list_del(&l->next);
+                        free(l);
+                        break;
+                }
+        }
+
+        pthread_mutex_unlock(&notifier.lock);
+}