proplist.h [include/cln/proplist.h]

1	// Property lists.
2
3	#ifndef _CL_PROPLIST_H
4	#define _CL_PROPLIST_H
5
6	#include "cln/symbol.h"
7	#include "cln/malloc.h"
8
9	namespace cln {
10
11	// The only extensible way to extend objects at runtime in an extensible
12	// and decentralized way (without having to modify the object's class)
13	// is to add a property table to every object.
14	// For the moment, only very few properties are planned, so lists should be
15	// enough. Since properties represent additional information about the object,
16	// there is no need for removing properties, so singly linked lists will be
17	// enough.
18
19	// This is the base class for all properties.
20	struct cl_property {
21	private:
22	cl_property* next;
23	public:
24	cl_symbol key;
25	// Constructor.
26	cl_property (const cl_symbol& k) : next (NULL), key (k) {}
27	// Destructor.
28	virtual ~cl_property () {}
29	// Allocation and deallocation.
30	void* operator new (size_t size) { return malloc_hook(size); }
31	void operator delete (void* ptr) { free_hook(ptr); }
32	private:
33	virtual void dummy ();
34	// Friend declarations. They are for the compiler. Just ignore them.
35	friend class cl_property_list;
36	};
37	#define SUBCLASS_cl_property() \
38	void* operator new (size_t size) { return malloc_hook(size); } \
39	void operator delete (void* ptr) { free_hook(ptr); }
40
41	struct cl_property_list {
42	private:
43	cl_property* list;
44	public:
45	cl_property* get_property (const cl_symbol& key);
46	void add_property (cl_property* new_property);
47	// Constructor.
48	cl_property_list () : list (NULL) {}
49	// Destructor.
50	~cl_property_list ();
51	};
52
53	} // namespace cln
54
55	#endif /* _CL_PROPLIST_H */
56