refactor: move locking responsibility to user

trie/include/trie.h

@@ -94,7 +94,8 @@ bool trie_add_no_lock(Trie *trie, const char *key, Entry *entry);
  * @param trie
  * @param entry entry to add
  * @param secure whether to generate a longer, more secure random key
- * @return the generated key
+ * @return pointer to the generated key. This pointer is safe to use after
+ * unlocking the trie, and should be freed manually.
  */
 char *trie_add_random(Trie *trie, Entry *entry, bool secure);
 
@@ -116,4 +117,28 @@ bool trie_remove(Trie *trie, const char *key);
  */
 size_t trie_size(Trie *trie);
 
+/*
+ * Acquire a read lock on the trie.
+ *
+ * @return 0 if successful, non-zero otherwise (return value of
+ * pthread_rwlock_rdlock)
+ */
+int trie_rlock(Trie *trie);
+
+/*
+ * Acquire a write lock on the trie.
+ *
+ * @return 0 if successful, non-zero otherwise (return value of
+ * pthread_rwlock_wrlock)
+ */
+int trie_wlock(Trie *trie);
+
+/*
+ * Release the lock on a trie after having acquired it beforehand.
+ *
+ * @return 0 if successful, non-zero otherwise (return value of
+ * pthread_rwlock_unlock)
+ */
+int trie_unlock(Trie *trie);
+
 #endif // AD3_TERNARYTRIE