object: add b_list object

b_list behaves exactly like b_queue, with two key differences:

  1) it is memory-managed like other b_objects, which means it
     is stored on the heap and ref-counted.
  2) it is not an invasive data structure, and will automatically
     create and manage list nodes that contain pointers to the
     list items.

object/include/blue/object/list.h

@@ -0,0 +1,67 @@
+#ifndef BLUE_OBJECT_LIST_H_
+#define BLUE_OBJECT_LIST_H_
+
+#include <blue/core/status.h>
+#include <blue/object/object.h>
+
+#define B_LIST(p) ((b_list *)(p))
+
+typedef struct b_list b_list;
+typedef struct b_list_entry b_list_entry;
+
+#define b_list_foreach(it, q)                                                  \
+	for (int z__b_unique_name() = b_list_iterator_begin(q, it);            \
+	     (it)->entry != NULL; b_list_iterator_next(it))
+
+typedef struct b_list_iterator {
+	b_queue_iterator _base;
+	const b_list *_q;
+	size_t i;
+	void *item;
+	b_list_entry *entry;
+} b_list_iterator;
+
+BLUE_API b_list *b_list_create(void);
+
+static inline b_list *b_list_retain(b_list *str)
+{
+	return B_LIST(b_retain(B_OBJECT(str)));
+}
+static inline void b_list_release(b_list *str)
+{
+	b_release(B_OBJECT(str));
+}
+
+BLUE_API bool b_list_empty(b_list *q);
+BLUE_API void *b_list_first_item(const b_list *q);
+BLUE_API void *b_list_last_item(const b_list *q);
+BLUE_API b_list_entry *b_list_first_entry(const b_list *q);
+BLUE_API b_list_entry *b_list_last_entry(const b_list *q);
+BLUE_API b_list_entry *b_list_next(const b_list_entry *entry);
+BLUE_API b_list_entry *b_list_prev(const b_list_entry *entry);
+
+BLUE_API size_t b_list_length(const b_list *q);
+
+BLUE_API b_list_entry *b_list_insert_before(
+	b_list *q, void *ptr, b_list_entry *before);
+BLUE_API b_list_entry *b_list_insert_after(
+	b_list *q, void *ptr, b_list_entry *after);
+
+BLUE_API b_list_entry *b_list_push_front(b_list *q, void *ptr);
+BLUE_API b_list_entry *b_list_push_back(b_list *q, void *ptr);
+
+BLUE_API void *b_list_pop_front(b_list *q);
+BLUE_API void *b_list_pop_back(b_list *q);
+
+BLUE_API b_status b_list_delete_item(b_list *q, void *ptr);
+BLUE_API b_status b_list_delete_entry(b_list *q, b_list_entry *entry);
+BLUE_API void b_list_delete_all(b_list *q);
+
+BLUE_API int b_list_iterator_begin(const b_list *q, b_list_iterator *it);
+BLUE_API bool b_list_iterator_next(b_list_iterator *it);
+BLUE_API b_status b_list_iterator_erase(b_list_iterator *it);
+BLUE_API bool b_list_iterator_is_valid(const b_list_iterator *it);
+
+BLUE_API void *b_list_entry_value(const b_list_entry *entry);
+
+#endif

object/include/blue/object/type.h

@@ -17,6 +17,7 @@ typedef uintptr_t b_object_type_id;
 typedef enum b_fundamental_type_id {
 	B_OBJECT_TYPE_NONE = 0,
 	B_OBJECT_TYPE_ANY,
+	B_OBJECT_TYPE_LIST,
 	B_OBJECT_TYPE_ARRAY,
 	B_OBJECT_TYPE_BUFFER,
 	B_OBJECT_TYPE_DICT,