This file is indexed.

/usr/include/firefox/nsAutoRef.h is in firefox-dev 11.0+build1-0ubuntu4.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  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
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set shiftwidth=4 tabstop=8 autoindent cindent expandtab: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is mozilla.org code.
 *
 * The Initial Developer of the Original Code is
 * The Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2008
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Karl Tomlinson <karlt+@karlt.net>, Mozilla Corporation
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

#ifndef nsAutoRef_h_
#define nsAutoRef_h_

#include "nscore.h" // for nsnull, bool

template <class T> class nsSimpleRef;
template <class T> class nsAutoRefBase;
template <class T> class nsReturnRef;
template <class T> class nsReturningRef;

/**
 * template <class T> class nsAutoRef
 *
 * A class that holds a handle to a resource that must be released.
 * No reference is added on construction.
 *
 * No copy constructor nor copy assignment operators are available, so the
 * resource will be held until released on destruction or explicitly
 * |reset()| or transferred through provided methods.
 *
 * The publicly available methods are the public methods on this class and its
 * public base classes |nsAutoRefBase<T>| and |nsSimpleRef<T>|.
 *
 * For ref-counted resources see also |nsCountedRef<T>|.
 * For function return values see |nsReturnRef<T>|.
 *
 * For each class |T|, |nsAutoRefTraits<T>| or |nsSimpleRef<T>| must be
 * specialized to use |nsAutoRef<T>| and |nsCountedRef<T>|.
 *
 * @param T  A class identifying the type of reference held by the
 *           |nsAutoRef<T>| and the unique set methods for managing references
 *           to the resource (defined by |nsAutoRefTraits<T>| or
 *           |nsSimpleRef<T>|).
 *
 *           Often this is the class representing the resource.  Sometimes a
 *           new possibly-incomplete class may need to be declared.
 *
 *
 * Example:  An Automatically closing file descriptor
 *
 * // References that are simple integral types (as file-descriptors are)
 * // usually need a new class to represent the resource and how to handle its
 * // references.
 * class nsRawFD;
 *
 * // Specializing nsAutoRefTraits<nsRawFD> describes how to manage file
 * // descriptors, so that nsAutoRef<nsRawFD> provides automatic closing of
 * // its file descriptor on destruction.
 * NS_SPECIALIZE_TEMPLATE
 * class nsAutoRefTraits<nsRawFD> {
 * public:
 *     // The file descriptor is held in an int.
 *     typedef int RawRef;
 *     // -1 means that there is no file associated with the handle.
 *     static int Void() { return -1; }
 *     // The file associated with a file descriptor is released with close().
 *     static void Release(RawRef aFD) { close(aFD); }
 * };
 *
 * // A function returning a file descriptor that must be closed.
 * nsReturnRef<nsRawFD> get_file(const char *filename) {
 *     // Constructing from a raw file descriptor assumes ownership.
 *     nsAutoRef<nsRawFD> fd(open(filename, O_RDONLY));
 *     fcntl(fd, F_SETFD, FD_CLOEXEC);
 *     return fd.out();
 * }
 *
 * void f() {
 *     unsigned char buf[1024];
 *
 *     // Hold a file descriptor for /etc/hosts in fd1.
 *     nsAutoRef<nsRawFD> fd1(get_file("/etc/hosts"));
 *
 *     nsAutoRef<nsRawFD> fd2;
 *     fd2.steal(fd1); // fd2 takes the file descriptor from fd1
 *     ssize_t count = read(fd1, buf, 1024); // error fd1 has no file
 *     count = read(fd2, buf, 1024); // reads from /etc/hosts
 *
 *     // If the file descriptor is not stored then it is closed.
 *     get_file("/etc/login.defs"); // login.defs is closed
 *
 *     // Now use fd1 to hold a file descriptor for /etc/passwd.
 *     fd1 = get_file("/etc/passwd");
 *
 *     // The nsAutoRef<nsRawFD> can give up the file descriptor if explicitly
 *     // instructed, but the caller must then ensure that the file is closed.
 *     int rawfd = fd1.disown();
 *
 *     // Assume ownership of another file descriptor.
 *     fd1.own(open("/proc/1/maps");
 *
 *     // On destruction, fd1 closes /proc/1/maps and fd2 closes /etc/hosts,
 *     // but /etc/passwd is not closed.
 * }
 *
 */


template <class T>
class nsAutoRef : public nsAutoRefBase<T>
{
protected:
    typedef nsAutoRef<T> ThisClass;
    typedef nsAutoRefBase<T> BaseClass;
    typedef nsSimpleRef<T> SimpleRef;
    typedef typename BaseClass::RawRefOnly RawRefOnly;
    typedef typename BaseClass::LocalSimpleRef LocalSimpleRef;

public:
    nsAutoRef()
    {
    }

    // Explicit construction is required so as not to risk unintentionally
    // releasing the resource associated with a raw ref.
    explicit nsAutoRef(RawRefOnly aRefToRelease)
        : BaseClass(aRefToRelease)
    {
    }

    // Construction from a nsReturnRef<T> function return value, which expects
    // to give up ownership, transfers ownership.
    // (nsReturnRef<T> is converted to const nsReturningRef<T>.)
    explicit nsAutoRef(const nsReturningRef<T>& aReturning)
        : BaseClass(aReturning)
    {
    }

    // The only assignment operator provided is for transferring from an
    // nsReturnRef smart reference, which expects to pass its ownership to
    // another object.
    //
    // With raw references and other smart references, the type of the lhs and
    // its taking and releasing nature is often not obvious from an assignment
    // statement.  Assignment from a raw ptr especially is not normally
    // expected to release the reference.
    //
    // Use |steal| for taking ownership from other smart refs.
    //
    // For raw references, use |own| to indicate intention to have the
    // resource released.
    //
    // Or, to create another owner of the same reference, use an nsCountedRef.

    ThisClass& operator=(const nsReturningRef<T>& aReturning)
    {
        BaseClass::steal(aReturning.mReturnRef);
        return *this;
    }

    // Conversion to a raw reference allow the nsAutoRef<T> to often be used
    // like a raw reference.
    operator typename SimpleRef::RawRef() const
    {
        return this->get();
    }

    // Transfer ownership from another smart reference.
    void steal(ThisClass& aOtherRef)
    {
        BaseClass::steal(aOtherRef);
    }

    // Assume ownership of a raw ref.
    //
    // |own| has similar function to |steal|, and is useful for receiving
    // ownership from a return value of a function.  It is named differently
    // because |own| requires more care to ensure that the function intends to
    // give away ownership, and so that |steal| can be safely used, knowing
    // that it won't steal ownership from any methods returning raw ptrs to
    // data owned by a foreign object.
    void own(RawRefOnly aRefToRelease)
    {
        BaseClass::own(aRefToRelease);
    }

    // Exchange ownership with |aOther|
    void swap(ThisClass& aOther)
    {
        LocalSimpleRef temp;
        temp.SimpleRef::operator=(this);
        SimpleRef::operator=(aOther);
        aOther.SimpleRef::operator=(temp);
    }

    // Release the reference now.
    void reset()
    {
        this->SafeRelease();
        LocalSimpleRef empty;
        SimpleRef::operator=(empty);
    }

    // Pass out the reference for a function return values.
    nsReturnRef<T> out()
    {
        return nsReturnRef<T>(this->disown());
    }

    // operator->() and disown() are provided by nsAutoRefBase<T>.
    // The default nsSimpleRef<T> provides get().

private:
    // No copy constructor
    explicit nsAutoRef(ThisClass& aRefToSteal);
};

/**
 * template <class T> class nsCountedRef
 *
 * A class that creates (adds) a new reference to a resource on construction
 * or assignment and releases on destruction.
 *
 * This class is similar to nsAutoRef<T> and inherits its methods, but also
 * provides copy construction and assignment operators that enable more than
 * one concurrent reference to the same resource.
 *
 * Specialize |nsAutoRefTraits<T>| or |nsSimpleRef<T>| to use this.  This
 * class assumes that the resource itself counts references and so can only be
 * used when |T| represents a reference-counting resource.
 */

template <class T>
class nsCountedRef : public nsAutoRef<T>
{
protected:
    typedef nsCountedRef<T> ThisClass;
    typedef nsAutoRef<T> BaseClass;
    typedef nsSimpleRef<T> SimpleRef;
    typedef typename BaseClass::RawRef RawRef;

public:
    nsCountedRef()
    {
    }

    // Construction and assignment from a another nsCountedRef
    // or a raw ref copies and increments the ref count.
    nsCountedRef(const ThisClass& aRefToCopy)
    {
        SimpleRef::operator=(aRefToCopy);
        SafeAddRef();
    }
    ThisClass& operator=(const ThisClass& aRefToCopy)
    {
        if (this == &aRefToCopy)
            return *this;

        this->SafeRelease();
        SimpleRef::operator=(aRefToCopy);
        SafeAddRef();
        return *this;
    }

    // Implicit conversion from another smart ref argument (to a raw ref) is
    // accepted here because construction and assignment safely creates a new
    // reference without interfering with the reference to copy.
    explicit nsCountedRef(RawRef aRefToCopy)
        : BaseClass(aRefToCopy)
    {
        SafeAddRef();
    }
    ThisClass& operator=(RawRef aRefToCopy)
    {
        this->own(aRefToCopy);
        SafeAddRef();
        return *this;
    }

    // Construction and assignment from an nsReturnRef function return value,
    // which expects to give up ownership, transfers ownership.
    explicit nsCountedRef(const nsReturningRef<T>& aReturning)
        : BaseClass(aReturning)
    {
    }
    ThisClass& operator=(const nsReturningRef<T>& aReturning)
    {
        BaseClass::operator=(aReturning);
        return *this;
    }

protected:
    // Increase the reference count if there is a resource.
    void SafeAddRef()
    {
        if (this->HaveResource())
            this->AddRef(this->get());
    }
};

/**
 * template <class T> class nsReturnRef
 *
 * A type for function return values that hold a reference to a resource that
 * must be released.  See also |nsAutoRef<T>::out()|.
 */

template <class T>
class nsReturnRef : public nsAutoRefBase<T>
{
protected:
    typedef nsAutoRefBase<T> BaseClass;
    typedef typename BaseClass::RawRefOnly RawRefOnly;

public:
    // For constructing a return value with no resource
    nsReturnRef()
    {
    }

    // For returning a smart reference from a raw reference that must be
    // released.  Explicit construction is required so as not to risk
    // unintentionally releasing the resource associated with a raw ref.
    explicit nsReturnRef(RawRefOnly aRefToRelease)
        : BaseClass(aRefToRelease)
    {
    }

    // Copy construction transfers ownership
    nsReturnRef(nsReturnRef<T>& aRefToSteal)
        : BaseClass(aRefToSteal)
    {
    }

    nsReturnRef(const nsReturningRef<T>& aReturning)
        : BaseClass(aReturning)
    {
    }

    // Conversion to a temporary (const) object referring to this object so
    // that the reference may be passed from a function return value
    // (temporary) to another smart reference.  There is no need to use this
    // explicitly.  Simply assign a nsReturnRef<T> function return value to a
    // smart reference.
    operator nsReturningRef<T>()
    {
        return nsReturningRef<T>(*this);
    }

    // No conversion to RawRef operator is provided on nsReturnRef, to ensure
    // that the return value is not carelessly assigned to a raw ptr (and the
    // resource then released).  If passing to a function that takes a raw
    // ptr, use get or disown as appropriate.
};

/**
 * template <class T> class nsReturningRef
 *
 * A class to allow ownership to be transferred from nsReturnRef function
 * return values.
 *
 * It should not be necessary for clients to reference this
 * class directly.  Simply pass an nsReturnRef<T> to a parameter taking an
 * |nsReturningRef<T>|.
 *
 * The conversion operator on nsReturnRef constructs a temporary wrapper of
 * class nsReturningRef<T> around a non-const reference to the nsReturnRef.
 * The wrapper can then be passed as an rvalue parameter.
 */

template <class T>
class nsReturningRef
{
private:
    friend class nsReturnRef<T>;

    explicit nsReturningRef(nsReturnRef<T>& aReturnRef)
        : mReturnRef(aReturnRef)
    {
    }
public:
    nsReturnRef<T>& mReturnRef;
};

/**
 * template <class T> class nsAutoRefTraits
 *
 * A class describing traits of references managed by the default
 * |nsSimpleRef<T>| implementation and thus |nsAutoRef<T>| and |nsCountedRef|.
 * The default |nsSimpleRef<T> is suitable for resources with handles that
 * have a void value.  (If there is no such void value for a handle,
 * specialize |nsSimpleRef<T>|.)
 *
 * Specializations must be provided for each class |T| according to the
 * following pattern:
 *
 * // The template parameter |T| should be a class such that the set of fields
 * // in class nsAutoRefTraits<T> is unique for class |T|.  Usually the
 * // resource object class is sufficient.  For handles that are simple
 * // integral typedefs, a new unique possibly-incomplete class may need to be
 * // declared.
 *
 * NS_SPECIALIZE_TEMPLATE
 * class nsAutoRefTraits<T>
 * {
 *     // Specializations must provide a typedef for RawRef, describing the
 *     // type of the handle to the resource.
 *     typedef <handle-type> RawRef;
 *
 *     // Specializations should define Void(), a function returning a value
 *     // suitable for a handle that does not have an associated resource.
 *     //
 *     // The return type must be a suitable as the parameter to a RawRef
 *     // constructor and operator==.
 *     //
 *     // If this method is not accessible then some limited nsAutoRef
 *     // functionality will still be available, but the default constructor,
 *     // |reset|, and most transfer of ownership methods will not be available.
 *     static <return-type> Void();
 *
 *     // Specializations must define Release() to properly finalize the
 *     // handle to a non-void custom-deleted or reference-counted resource.
 *     static void Release(RawRef aRawRef);
 *
 *     // For reference-counted resources, if |nsCountedRef<T>| is to be used,
 *     // specializations must define AddRef to increment the reference count
 *     // held by a non-void handle.
 *     // (AddRef() is not necessary for |nsAutoRef<T>|.)
 *     static void AddRef(RawRef aRawRef);
 * };
 *
 * See nsPointerRefTraits for example specializations for simple pointer
 * references.  See nsAutoRef for an example specialization for a non-pointer
 * reference.
 */

template <class T> class nsAutoRefTraits;

/**
 * template <class T> class nsPointerRefTraits
 *
 * A convenience class useful as a base class for specializations of
 * |nsAutoRefTraits<T>| where the handle to the resource is a pointer to |T|.
 * By inheriting from this class, definitions of only Release(RawRef) and
 * possibly AddRef(RawRef) need to be added.
 *
 * Examples of use:
 *
 * NS_SPECIALIZE_TEMPLATE
 * class nsAutoRefTraits<PRFileDesc> : public nsPointerRefTraits<PRFileDesc>
 * {
 * public:
 *     static void Release(PRFileDesc *ptr) { PR_Close(ptr); }
 * };
 *
 * NS_SPECIALIZE_TEMPLATE
 * class nsAutoRefTraits<FcPattern> : public nsPointerRefTraits<FcPattern>
 * {
 * public:
 *     static void Release(FcPattern *ptr) { FcPatternDestroy(ptr); }
 *     static void AddRef(FcPattern *ptr) { FcPatternReference(ptr); }
 * };
 */

template <class T>
class nsPointerRefTraits
{
public:
    // The handle is a pointer to T.
    typedef T* RawRef;
    // A NULL pointer does not have a resource.
    static RawRef Void() { return nsnull; };
};

/**
 * template <class T> class nsSimpleRef
 *
 * Constructs a non-smart reference, and provides methods to test whether
 * there is an associated resource and (if so) get its raw handle.
 *
 * A default implementation is suitable for resources with handles that have a
 * void value.  This is not intended for direct use but used by |nsAutoRef<T>|
 * and thus |nsCountedRef<T>|.
 *
 * Specialize this class if there is no particular void value for the resource
 * handle.  A specialized implementation must also provide Release(RawRef),
 * and, if |nsCountedRef<T>| is required, AddRef(RawRef), as described in
 * nsAutoRefTraits<T>.
 */

template <class T>
class nsSimpleRef : protected nsAutoRefTraits<T>
{
protected:
    // The default implementation uses nsAutoRefTrait<T>.
    // Specializations need not define this typedef.
    typedef nsAutoRefTraits<T> Traits;
    // The type of the handle to the resource.
    // A specialization must provide a typedef for RawRef.
    typedef typename Traits::RawRef RawRef;

    // Construct with no resource.
    //
    // If this constructor is not accessible then some limited nsAutoRef
    // functionality will still be available, but the default constructor,
    // |reset|, and most transfer of ownership methods will not be available.
    nsSimpleRef()
        : mRawRef(Traits::Void())
    {
    }
    // Construct with a handle to a resource.
    // A specialization must provide this. 
    nsSimpleRef(RawRef aRawRef)
        : mRawRef(aRawRef)
    {
    }

    // Test whether there is an associated resource.  A specialization must
    // provide this.  The function is permitted to always return true if the
    // default constructor is not accessible, or if Release (and AddRef) can
    // deal with void handles.
    bool HaveResource() const
    {
        return mRawRef != Traits::Void();
    }

public:
    // A specialization must provide get() or loose some functionality.  This
    // is inherited by derived classes and the specialization may choose
    // whether it is public or protected.
    RawRef get() const
    {
        return mRawRef;
    }

private:
    RawRef mRawRef;
};


/**
 * template <class T> class nsAutoRefBase
 *
 * Internal base class for |nsAutoRef<T>| and |nsReturnRef<T>|.
 * Adds release on destruction to a |nsSimpleRef<T>|.
 */

template <class T>
class nsAutoRefBase : public nsSimpleRef<T>
{
protected:
    typedef nsAutoRefBase<T> ThisClass;
    typedef nsSimpleRef<T> SimpleRef;
    typedef typename SimpleRef::RawRef RawRef;

    nsAutoRefBase()
    {
    }

    // A type for parameters that should be passed a raw ref but should not
    // accept implicit conversions (from another smart ref).  (The only
    // conversion to this type is from a raw ref so only raw refs will be
    // accepted.)
    class RawRefOnly
    {
    public:
        RawRefOnly(RawRef aRawRef)
            : mRawRef(aRawRef)
        {
        }
        operator RawRef() const
        {
            return mRawRef;
        }
    private:
        RawRef mRawRef;
    };

    // Construction from a raw ref assumes ownership
    explicit nsAutoRefBase(RawRefOnly aRefToRelease)
        : SimpleRef(aRefToRelease)
    {
    }

    // Constructors that steal ownership
    explicit nsAutoRefBase(ThisClass& aRefToSteal)
        : SimpleRef(aRefToSteal.disown())
    {
    }
    explicit nsAutoRefBase(const nsReturningRef<T>& aReturning)
        : SimpleRef(aReturning.mReturnRef.disown())
    {
    }

    ~nsAutoRefBase()
    {
        SafeRelease();
    }

    // An internal class providing access to protected nsSimpleRef<T>
    // constructors for construction of temporary simple references (that are
    // not ThisClass).
    class LocalSimpleRef : public SimpleRef
    {
    public:
        LocalSimpleRef()
        {
        }
        explicit LocalSimpleRef(RawRef aRawRef)
            : SimpleRef(aRawRef)
        {
        }
    };

private:
    ThisClass& operator=(const ThisClass& aSmartRef);
    
public:
    RawRef operator->() const
    {
        return this->get();
    }

    // Transfer ownership to a raw reference.
    //
    // THE CALLER MUST ENSURE THAT THE REFERENCE IS EXPLICITLY RELEASED.
    //
    // Is this really what you want to use?  Using this removes any guarantee
    // of release.  Use nsAutoRef<T>::out() for return values, or an
    // nsAutoRef<T> modifiable lvalue for an out parameter.  Use disown() when
    // the reference must be stored in a POD type object, such as may be
    // preferred for a namespace-scope object with static storage duration,
    // for example.
    RawRef disown()
    {
        RawRef temp = this->get();
        LocalSimpleRef empty;
        SimpleRef::operator=(empty);
        return temp;
    }

protected:
    // steal and own are protected because they make no sense on nsReturnRef,
    // but steal is implemented on this class for access to aOtherRef.disown()
    // when aOtherRef is an nsReturnRef;

    // Transfer ownership from another smart reference.
    void steal(ThisClass& aOtherRef)
    {
        own(aOtherRef.disown());
    }
    // Assume ownership of a raw ref.
    void own(RawRefOnly aRefToRelease)
    {
        SafeRelease();
        LocalSimpleRef ref(aRefToRelease);
        SimpleRef::operator=(ref);
    }

    // Release a resource if there is one.
    void SafeRelease()
    {
        if (this->HaveResource())
            this->Release(this->get());
    }
};

#endif // !defined(nsAutoRef_h_)