Disabled external gits

cs453-ca/CS453-2021-project/reference/shared-lock.h

@@ -0,0 +1,53 @@
+#pragma once
+
+// Requested feature: pthread_rwlock_t
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#ifndef __USE_XOPEN2K
+#define __USE_XOPEN2K
+#endif
+
+#include <pthread.h>
+#include <stdbool.h>
+
+/**
+ * @brief A lock that can be taken exclusively but also shared. Contrarily to
+ * exclusive locks, shared locks do not have wait/wake_up capabilities.
+ */
+struct shared_lock_t {
+    pthread_rwlock_t rwlock;
+};
+
+/** Initialize the given lock.
+ * @param lock Lock to initialize
+ * @return Whether the operation is a success
+**/
+bool shared_lock_init(struct shared_lock_t* lock);
+
+/** Clean the given lock up.
+ * @param lock Lock to clean up
+**/
+void shared_lock_cleanup(struct shared_lock_t* lock);
+
+/** Wait and acquire the given lock exclusively.
+ * @param lock Lock to acquire
+ * @return Whether the operation is a success
+**/
+bool shared_lock_acquire(struct shared_lock_t* lock);
+
+/** Release the given lock that has been taken exclusively.
+ * @param lock Lock to release
+**/
+void shared_lock_release(struct shared_lock_t* lock);
+
+/** Wait and acquire the given lock non-exclusively.
+ * @param lock Lock to acquire
+ * @return Whether the operation is a success
+**/
+bool shared_lock_acquire_shared(struct shared_lock_t* lock);
+
+/** Release the given lock that has been taken non-exclusively.
+ * @param lock Lock to release
+**/
+void shared_lock_release_shared(struct shared_lock_t* lock);