feat(heap): thread-safety features

include/vieter_heap.h

@@ -11,7 +11,7 @@ typedef enum vieter_heap_error {
 } vieter_heap_error;
 
 /*
- * Allocate and initalize an empty heap.
+ * Allocate and initialize an empty heap.
  */
 vieter_heap *vieter_heap_init();
 
@@ -41,4 +41,22 @@ vieter_heap_error vieter_heap_pop(void **out, vieter_heap *heap);
  */
 vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap);
 
+/*
+ * Acquire a read lock on the heap. Return value is the result of
+ * pthread_rwlock_rdlock.
+ */
+int vieter_heap_rlock(vieter_heap *heap);
+
+/*
+ * Acquire a write lock on the heap. Return value is the result of
+ * pthread_rwlock_wrlock.
+ */
+int vieter_heap_wlock(vieter_heap *heap);
+
+/*
+ * Unlock the lock after having acquired it. Return value is the result of
+ * pthread_rwlock_unlock.
+ */
+int vieter_heap_unlock(vieter_heap *heap);
+
 #endif

src/heap/vieter_heap.c

@@ -2,7 +2,13 @@
 
 #include <stdlib.h>
 
-vieter_heap *vieter_heap_init() { return calloc(1, sizeof(vieter_heap)); }
+vieter_heap *vieter_heap_init() {
+  vieter_heap *heap = calloc(1, sizeof(vieter_heap));
+
+  pthread_rwlock_init(&heap->lock, NULL);
+
+  return heap;
+}
 
 uint64_t vieter_heap_size(vieter_heap *heap) {
   uint64_t size = 0;
@@ -76,3 +82,15 @@ vieter_heap_error vieter_heap_peek(void **out, vieter_heap *heap) {
 
   return vieter_heap_ok;
 }
+
+int vieter_heap_rlock(vieter_heap *heap) {
+  return pthread_rwlock_rdlock(&heap->lock);
+}
+
+int vieter_heap_wlock(vieter_heap *heap) {
+  return pthread_rwlock_wrlock(&heap->lock);
+}
+
+int vieter_heap_unlock(vieter_heap *heap) {
+  return pthread_rwlock_unlock(&heap->lock);
+}

src/heap/vieter_heap_internal.h

@@ -1,6 +1,8 @@
 #include "vieter_heap.h"
 #include "vieter_heap_tree.h"
+#include <pthread.h>
 
 struct vieter_heap {
   vieter_heap_node *tree;
+  pthread_rwlock_t lock;
 };

src/heap/vieter_heap_tree.h

@@ -18,7 +18,7 @@ typedef struct vieter_heap_node {
 } vieter_heap_node;
 
 /*
- * Allocate an initialize a heap node object.
+ * Allocate and initialize a heap node object.
  */
 vieter_heap_node *vieter_heap_node_init();