summaryrefslogtreecommitdiff
path: root/indra/llcorehttp/_refcounted.h
blob: 7f713f229836a7c2f34ba6ba01a42b850ad315f6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/** 
 * @file _refcounted.h
 * @brief Atomic, thread-safe ref counting and destruction mixin class
 *
 * $LicenseInfo:firstyear=2012&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2012, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LLCOREINT__REFCOUNTED_H_
#define LLCOREINT__REFCOUNTED_H_


#include "linden_common.h"

#include "fix_macros.h"
#include <boost/thread.hpp>
#include <boost/intrusive_ptr.hpp>

#include "llapr.h"


namespace LLCoreInt
{


class RefCounted
{
private:
	RefCounted();								// Not defined - may not be default constructed
	void operator=(const RefCounted &);			// Not defined
	
public:
	explicit RefCounted(bool const implicit)
		: mRefCount(implicit)
		{}

	// ref-count interface
	void addRef() const;
	void release() const;
	bool isLastRef() const;
	S32 getRefCount() const;
	void noRef() const;

	static const S32			NOT_REF_COUNTED = -1;
	
protected:
	virtual ~RefCounted();
	virtual void destroySelf();

private:
	mutable LLAtomicS32			mRefCount;

}; // end class RefCounted


inline void RefCounted::addRef() const
{
	S32 count(++mRefCount);
	llassert_always(count >= 0);
}


inline void RefCounted::release() const
{
	S32 count(mRefCount);
	llassert_always(count != NOT_REF_COUNTED);
	llassert_always(count > 0);
	count = --mRefCount;

	// clean ourselves up if that was the last reference
	if (0 == count)
	{
		const_cast<RefCounted *>(this)->destroySelf();
	}
}


inline bool RefCounted::isLastRef() const
{
	const S32 count(mRefCount);
	llassert_always(count != NOT_REF_COUNTED);
	llassert_always(count >= 1);
	return (1 == count);
}


inline S32 RefCounted::getRefCount() const
{
	const S32 result(mRefCount);
	return result;
}


inline void RefCounted::noRef() const
{
	llassert_always(mRefCount <= 1);
	mRefCount = NOT_REF_COUNTED;
}


inline void RefCounted::destroySelf()
{
	delete this;
}

/**
 * boost::intrusive_ptr may be used to manage RefCounted classes.
 * Unfortunately RefCounted and boost::intrusive_ptr use different conventions
 * for the initial refcount value. To avoid leaky (immortal) objects, you
 * should really construct boost::intrusive_ptr<RefCounted*>(rawptr, false).
 * IntrusivePtr<T> encapsulates that for you.
 */
template <typename T>
struct IntrusivePtr: public boost::intrusive_ptr<T>
{
	IntrusivePtr():
		boost::intrusive_ptr<T>()
	{}
	IntrusivePtr(T* p):
		boost::intrusive_ptr<T>(p, false)
	{}
};

inline void intrusive_ptr_add_ref(RefCounted* p)
{
	p->addRef();
}

inline void intrusive_ptr_release(RefCounted* p)
{
	p->release();
}

} // end namespace LLCoreInt


#endif	// LLCOREINT__REFCOUNTED_H_