summaryrefslogtreecommitdiff
path: root/indra/llcommon/llpointer.h
blob: 9a6453ea482e9ecc97fd8fa027551e65b4be1443 (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
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
/** 
 * @file llpointer.h
 * @brief A reference-counted pointer for objects derived from LLRefCount
 *
 * $LicenseInfo:firstyear=2002&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, 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 LLPOINTER_H
#define LLPOINTER_H

#include "llerror.h"	// *TODO: consider eliminating this
#include "llmutex.h"

//----------------------------------------------------------------------------
// RefCount objects should generally only be accessed by way of LLPointer<>'s
// NOTE: LLPointer<LLFoo> x = new LLFoo(); MAY NOT BE THREAD SAFE
//   if LLFoo::LLFoo() does anything like put itself in an update queue.
//   The queue may get accessed before it gets assigned to x.
// The correct implementation is:
//   LLPointer<LLFoo> x = new LLFoo; // constructor does not do anything interesting
//   x->instantiate(); // does stuff like place x into an update queue

// see llthread.h for LLThreadSafeRefCount

//----------------------------------------------------------------------------

// Note: relies on Type having ref() and unref() methods
template <class Type> class LLPointer
{
public:

	LLPointer() : 
		mPointer(NULL)
	{
	}

	LLPointer(Type* ptr) : 
		mPointer(ptr)
	{
		ref();
	}

	LLPointer(const LLPointer<Type>& ptr) : 
		mPointer(ptr.mPointer)
	{
		ref();
	}

	// support conversion up the type hierarchy.  See Item 45 in Effective C++, 3rd Ed.
	template<typename Subclass>
	LLPointer(const LLPointer<Subclass>& ptr) : 
		mPointer(ptr.get())
	{
		ref();
	}

	~LLPointer()								
	{
		unref();
	}

	Type*	get() const							{ return mPointer; }
	const Type*	operator->() const				{ return mPointer; }
	Type*	operator->()						{ return mPointer; }
	const Type&	operator*() const				{ return *mPointer; }
	Type&	operator*()							{ return *mPointer; }

	operator BOOL()  const						{ return (mPointer != NULL); }
	operator bool()  const						{ return (mPointer != NULL); }
	bool operator!() const						{ return (mPointer == NULL); }
	bool isNull() const							{ return (mPointer == NULL); }
	bool notNull() const						{ return (mPointer != NULL); }

	operator Type*()       const				{ return mPointer; }
	bool operator !=(Type* ptr) const           { return (mPointer != ptr); 	}
	bool operator ==(Type* ptr) const           { return (mPointer == ptr); 	}
	bool operator ==(const LLPointer<Type>& ptr) const           { return (mPointer == ptr.mPointer); 	}
	bool operator < (const LLPointer<Type>& ptr) const           { return (mPointer < ptr.mPointer); 	}
	bool operator > (const LLPointer<Type>& ptr) const           { return (mPointer > ptr.mPointer); 	}

	LLPointer<Type>& operator =(Type* ptr)                   
	{ 
		assign(ptr);
		return *this; 
	}

	LLPointer<Type>& operator =(const LLPointer<Type>& ptr)  
	{ 
		assign(ptr);
		return *this; 
	}

	// support assignment up the type hierarchy. See Item 45 in Effective C++, 3rd Ed.
	template<typename Subclass>
	LLPointer<Type>& operator =(const LLPointer<Subclass>& ptr)  
	{ 
		assign(ptr.get());
		return *this; 
	}
	
	// Just exchange the pointers, which will not change the reference counts.
	static void swap(LLPointer<Type>& a, LLPointer<Type>& b)
	{
		Type* temp = a.mPointer;
		a.mPointer = b.mPointer;
		b.mPointer = temp;
	}

protected:
#ifdef LL_LIBRARY_INCLUDE
	void ref();                             
	void unref();
#else

	void assign(const LLPointer<Type>& ptr)
	{
		if( mPointer != ptr.mPointer )
		{
			unref(); 
			mPointer = ptr.mPointer;
			ref();
		}
	}
	void ref()                             
	{ 
		if (mPointer)
		{
			mPointer->ref();
		}
	}

	void unref()
	{
		if (mPointer)
		{
			Type *temp = mPointer;
			mPointer = NULL;
			temp->unref();
			if (mPointer != NULL)
			{
				LL_WARNS() << "Unreference did assignment to non-NULL because of destructor" << LL_ENDL;
				unref();
			}
		}
	}
#endif
protected:
	Type*	mPointer;
};

template <class Type> class LLConstPointer
{
public:
	LLConstPointer() : 
		mPointer(NULL)
	{
	}

	LLConstPointer(const Type* ptr) : 
		mPointer(ptr)
	{
		ref();
	}

	LLConstPointer(const LLConstPointer<Type>& ptr) : 
		mPointer(ptr.mPointer)
	{
		ref();
	}

	// support conversion up the type hierarchy.  See Item 45 in Effective C++, 3rd Ed.
	template<typename Subclass>
	LLConstPointer(const LLConstPointer<Subclass>& ptr) : 
		mPointer(ptr.get())
	{
		ref();
	}

	~LLConstPointer()
	{
		unref();
	}

	const Type*	get() const						{ return mPointer; }
	const Type*	operator->() const				{ return mPointer; }
	const Type&	operator*() const				{ return *mPointer; }

	operator BOOL()  const						{ return (mPointer != NULL); }
	operator bool()  const						{ return (mPointer != NULL); }
	bool operator!() const						{ return (mPointer == NULL); }
	bool isNull() const							{ return (mPointer == NULL); }
	bool notNull() const						{ return (mPointer != NULL); }

	operator const Type*()       const			{ return mPointer; }
	bool operator !=(const Type* ptr) const     { return (mPointer != ptr); 	}
	bool operator ==(const Type* ptr) const     { return (mPointer == ptr); 	}
	bool operator ==(const LLConstPointer<Type>& ptr) const           { return (mPointer == ptr.mPointer); 	}
	bool operator < (const LLConstPointer<Type>& ptr) const           { return (mPointer < ptr.mPointer); 	}
	bool operator > (const LLConstPointer<Type>& ptr) const           { return (mPointer > ptr.mPointer); 	}

	LLConstPointer<Type>& operator =(const Type* ptr)                   
	{
		if( mPointer != ptr )
		{
			unref(); 
			mPointer = ptr; 
			ref();
		}

		return *this; 
	}

	LLConstPointer<Type>& operator =(const LLConstPointer<Type>& ptr)  
	{ 
		if( mPointer != ptr.mPointer )
		{
			unref(); 
			mPointer = ptr.mPointer;
			ref();
		}
		return *this; 
	}

	// support assignment up the type hierarchy. See Item 45 in Effective C++, 3rd Ed.
	template<typename Subclass>
	LLConstPointer<Type>& operator =(const LLConstPointer<Subclass>& ptr)  
	{ 
		if( mPointer != ptr.get() )
		{
			unref(); 
			mPointer = ptr.get();
			ref();
		}
		return *this; 
	}
	
	// Just exchange the pointers, which will not change the reference counts.
	static void swap(LLConstPointer<Type>& a, LLConstPointer<Type>& b)
	{
		const Type* temp = a.mPointer;
		a.mPointer = b.mPointer;
		b.mPointer = temp;
	}

protected:
#ifdef LL_LIBRARY_INCLUDE
	void ref();                             
	void unref();
#else
	void ref()                             
	{ 
		if (mPointer)
		{
			mPointer->ref();
		}
	}

	void unref()
	{
		if (mPointer)
		{
			const Type *tempp = mPointer;
			mPointer = NULL;
			tempp->unref();
			if (mPointer != NULL)
			{
				LL_WARNS() << "Unreference did assignment to non-NULL because of destructor" << LL_ENDL;
				unref();
			}
		}
	}
#endif
protected:
	const Type*	mPointer;
};

template<typename Type>
class LLCopyOnWritePointer : public LLPointer<Type>
{
public:
	typedef LLCopyOnWritePointer<Type> self_t;
    typedef LLPointer<Type> pointer_t;
    
	LLCopyOnWritePointer() 
	:	mStayUnique(false)
	{}

	LLCopyOnWritePointer(Type* ptr) 
	:	LLPointer<Type>(ptr),
		mStayUnique(false)
	{}

	LLCopyOnWritePointer(LLPointer<Type>& ptr)
	:	LLPointer<Type>(ptr),
		mStayUnique(false)
	{
		if (ptr.mForceUnique)
		{
			makeUnique();
		}
	}

	Type* write()
	{
		makeUnique();
		return pointer_t::mPointer;
	}

	void makeUnique()
	{
		if (pointer_t::notNull() && pointer_t::mPointer->getNumRefs() > 1)
		{
			*(pointer_t* )(this) = new Type(*pointer_t::mPointer);
		}
	}

	const Type*	operator->() const	{ return pointer_t::mPointer; }
	const Type&	operator*() const	{ return *pointer_t::mPointer; }

	void setStayUnique(bool stay) { makeUnique(); mStayUnique = stay; }
private:
	bool mStayUnique;
};

#endif