RefCounter.h revision ede7bdf4cf4f9ad1a0b8d74c715dfa45e866b8d5 
1//===-- RefCounter.h --------------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef liblldb_RefCounter_h_
11#define liblldb_RefCounter_h_
12
13#include "lldb/lldb-public.h"
14
15namespace lldb_utility {
16
17//----------------------------------------------------------------------
18// A simple reference counter object. You need an uint32_t* to use it
19// Once that is in place, everyone who needs to ref-count, can say
20// RefCounter ref(ptr);
21// (of course, the pointer is a shared resource, and must be accessible to
22// everyone who needs it). Synchronization is handled by RefCounter itself
23// To check if more than 1 RefCounter is attached to the same value, you can
24// either call shared(), or simply cast ref to bool
25// The counter is decreased each time a RefCounter to it goes out of scope
26//----------------------------------------------------------------------
27class RefCounter
28{
29public:
30    typedef uint32_t value_type;
31
32    RefCounter(value_type* ctr);
33
34    ~RefCounter();
35
36private:
37    value_type* m_counter;
38    DISALLOW_COPY_AND_ASSIGN (RefCounter);
39
40    template <class T>
41    inline T
42    increment(T* t)
43    {
44        return __sync_fetch_and_add(t, 1);
45    }
46
47    template <class T>
48    inline T
49    decrement(T* t)
50    {
51        return __sync_fetch_and_add(t, -1);
52    }
53
54};
55
56} // namespace lldb_utility
57
58#endif // #ifndef liblldb_RefCounter_h_
59