Initial garbage colletor implementation

test/test_refcount.c

@@ -7,49 +7,78 @@ typedef struct A {
     int num;
     RefcountEntry refcount;
     char *str;
+    struct A *next;
 } A;
 
 A *make_a(RefcountContext *c, int n, const char *s) {
     A *a = counting_malloc(sizeof(A));
     a->num = n;
     a->str = counting_strdup(s);
+    a->next = NULL;
     refcount_context_init_obj(c, a);
     return a;
 }
 
-void destroy_callback(void *a_raw) {
+bool held_refs_callback(void *a_raw, RefcountList **out, void *ignored) {
+    A *a = a_raw;
+    if (a->next) {
+        *out = refcount_list_push_full(*out, a->next, &COUNTING_ALLOCATOR);
+    }
+    return true;
+}
+
+void destroy_callback(void *a_raw, void *ignored) {
     A *a = a_raw;
     counting_free(a->str);
     counting_free(a);
 }
 
-int main() {
-    refcount_global_allocator = &COUNTING_ALLOCATOR;
-
+int main(int argc, const char **argv) {
     RefcountContext *c =
-        refcount_make_context(offsetof(A, refcount), NULL, destroy_callback);
+        refcount_make_context(offsetof(A, refcount), held_refs_callback,
+                              destroy_callback, NULL, &COUNTING_ALLOCATOR);
 
     A *a = make_a(c, 10, "Hello world\n");
     assert(!refcount_context_is_static(c, a));
     assert(refcount_context_num_refs(c, a) == 0);
 
-    refcount_context_ref(c, a);
+    a = refcount_context_ref(c, a);
     assert(refcount_context_num_refs(c, a) == 1);
 
-    refcount_context_ref(c, a);
+    a = refcount_context_ref(c, a);
     assert(refcount_context_num_refs(c, a) == 2);
 
-    refcount_context_unref(c, a);
+    a = refcount_context_unref(c, a);
     assert(refcount_context_num_refs(c, a) == 1);
 
-    refcount_context_float(c, a);
+    a = refcount_context_float(c, a);
+    assert(a);
     assert(refcount_context_num_refs(c, a) == 0);
 
     refcount_context_ref(c, a);
     assert(refcount_context_num_refs(c, a) == 1);
 
+    a = refcount_context_unref(c, a);
+    assert(!a);
+
+    a = make_a(c, 10, "Hello World\n");
+    A *b = make_a(c, 42, "The answer!");
+    a->next = refcount_context_ref(c, b);
+    assert(refcount_context_num_refs(c, a->next) == 1);
+    assert(refcount_context_num_refs(c, a) == 0);
+
     refcount_context_unref(c, a);
 
+    a = make_a(c, 'a', "a");
+    a->next = refcount_context_ref(c, a);
+    assert(refcount_context_num_refs(c, a) == 1);
+
+    refcount_context_ref(c, a);
+    refcount_context_unref(c, a);
+    assert(refcount_context_num_refs(c, a) == 1);
+
+    refcount_context_garbage_collect(c);
+
     refcount_context_destroy(c);
 
     check_allocator_status();