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Side by Side Diff: webrtc/base/scoped_ptr.h

Issue 1797463002: Make rtc::scoped_ptr a type alias for std::unique_ptr (Closed) Base URL: https://chromium.googlesource.com/external/webrtc.git@master
Patch Set: Created 4 years, 8 months ago
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1 /* 1 /*
2 * Copyright 2012 The WebRTC Project Authors. All rights reserved. 2 * Copyright 2012 The WebRTC Project Authors. All rights reserved.
3 * 3 *
4 * Use of this source code is governed by a BSD-style license 4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source 5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found 6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may 7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree. 8 * be found in the AUTHORS file in the root of the source tree.
9 */ 9 */
10 10
11 // Borrowed from Chromium's src/base/memory/scoped_ptr.h. 11 // This entire file is deprecated, and will be removed in XXXX 2016. Use
12 12 // std::unique_ptr instead!
13 // Scopers help you manage ownership of a pointer, helping you easily manage a
14 // pointer within a scope, and automatically destroying the pointer at the end
15 // of a scope. There are two main classes you will use, which correspond to the
16 // operators new/delete and new[]/delete[].
17 //
18 // Example usage (scoped_ptr<T>):
19 // {
20 // scoped_ptr<Foo> foo(new Foo("wee"));
21 // } // foo goes out of scope, releasing the pointer with it.
22 //
23 // {
24 // scoped_ptr<Foo> foo; // No pointer managed.
25 // foo.reset(new Foo("wee")); // Now a pointer is managed.
26 // foo.reset(new Foo("wee2")); // Foo("wee") was destroyed.
27 // foo.reset(new Foo("wee3")); // Foo("wee2") was destroyed.
28 // foo->Method(); // Foo::Method() called.
29 // foo.get()->Method(); // Foo::Method() called.
30 // SomeFunc(foo.release()); // SomeFunc takes ownership, foo no longer
31 // // manages a pointer.
32 // foo.reset(new Foo("wee4")); // foo manages a pointer again.
33 // foo.reset(); // Foo("wee4") destroyed, foo no longer
34 // // manages a pointer.
35 // } // foo wasn't managing a pointer, so nothing was destroyed.
36 //
37 // Example usage (scoped_ptr<T[]>):
38 // {
39 // scoped_ptr<Foo[]> foo(new Foo[100]);
40 // foo.get()->Method(); // Foo::Method on the 0th element.
41 // foo[10].Method(); // Foo::Method on the 10th element.
42 // }
43 //
44 // These scopers also implement part of the functionality of C++11 unique_ptr
45 // in that they are "movable but not copyable." You can use the scopers in the
46 // parameter and return types of functions to signify ownership transfer in to
47 // and out of a function. When calling a function that has a scoper as the
48 // argument type, it must be called with the result of calling std::move on an
49 // analogous scoper, or another function that generates a temporary; passing by
50 // copy will NOT work. Here is an example using scoped_ptr:
51 //
52 // void TakesOwnership(scoped_ptr<Foo> arg) {
53 // // Do something with arg
54 // }
55 // scoped_ptr<Foo> CreateFoo() {
56 // // No need for calling std::move because we are constructing a temporary
57 // // for the return value.
58 // return scoped_ptr<Foo>(new Foo("new"));
59 // }
60 // scoped_ptr<Foo> PassThru(scoped_ptr<Foo> arg) {
61 // return std::move(arg);
62 // }
63 //
64 // {
65 // scoped_ptr<Foo> ptr(new Foo("yay")); // ptr manages Foo("yay").
66 // TakesOwnership(std::move(ptr)); // ptr no longer owns Foo("yay").
67 // scoped_ptr<Foo> ptr2 = CreateFoo(); // ptr2 owns the return Foo.
68 // scoped_ptr<Foo> ptr3 = // ptr3 now owns what was in ptr2.
69 // PassThru(std::move(ptr2)); // ptr2 is correspondingly nullptr.
70 // }
71 //
72 // Notice that if you do not call std::move when returning from PassThru(), or
73 // when invoking TakesOwnership(), the code will not compile because scopers
74 // are not copyable; they only implement move semantics which require calling
75 // std::move to signify a destructive transfer of state. CreateFoo() is
76 // different though because we are constructing a temporary on the return line
77 // and thus can avoid needing to call std::move.
78 13
79 #ifndef WEBRTC_BASE_SCOPED_PTR_H__ 14 #ifndef WEBRTC_BASE_SCOPED_PTR_H__
80 #define WEBRTC_BASE_SCOPED_PTR_H__ 15 #define WEBRTC_BASE_SCOPED_PTR_H__
81 16
82 // This is an implementation designed to match the anticipated future TR2 17 // All these #includes are left to maximize backwards compatibility.
83 // implementation of the scoped_ptr class.
84 18
85 #include <assert.h> 19 #include <assert.h>
86 #include <stddef.h> 20 #include <stddef.h>
87 #include <stdlib.h> 21 #include <stdlib.h>
88 22
89 #include <algorithm> // For std::swap(). 23 #include <algorithm>
90 #include <cstddef> 24 #include <cstddef>
91 #include <memory> 25 #include <memory>
92 26
93 #include "webrtc/base/constructormagic.h" 27 #include "webrtc/base/constructormagic.h"
94 #include "webrtc/base/template_util.h" 28 #include "webrtc/base/template_util.h"
95 #include "webrtc/typedefs.h" 29 #include "webrtc/typedefs.h"
96 30
97 namespace rtc { 31 namespace rtc {
98 32
99 // Function object which deletes its parameter, which must be a pointer. 33 template <typename T, typename Deleter = std::default_delete<T>>
100 // If C is an array type, invokes 'delete[]' on the parameter; otherwise, 34 using scoped_ptr = std::unique_ptr<T, Deleter>;
101 // invokes 'delete'. The default deleter for scoped_ptr<T>.
102 template <class T>
103 struct DefaultDeleter {
104 DefaultDeleter() {}
105 template <typename U> DefaultDeleter(const DefaultDeleter<U>& other) {
106 // IMPLEMENTATION NOTE: C++11 20.7.1.1.2p2 only provides this constructor
107 // if U* is implicitly convertible to T* and U is not an array type.
108 //
109 // Correct implementation should use SFINAE to disable this
110 // constructor. However, since there are no other 1-argument constructors,
111 // using a static_assert based on is_convertible<> and requiring
112 // complete types is simpler and will cause compile failures for equivalent
113 // misuses.
114 //
115 // Note, the is_convertible<U*, T*> check also ensures that U is not an
116 // array. T is guaranteed to be a non-array, so any U* where U is an array
117 // cannot convert to T*.
118 enum { T_must_be_complete = sizeof(T) };
119 enum { U_must_be_complete = sizeof(U) };
120 static_assert(rtc::is_convertible<U*, T*>::value,
121 "U* must implicitly convert to T*");
122 }
123 inline void operator()(T* ptr) const {
124 enum { type_must_be_complete = sizeof(T) };
125 delete ptr;
126 }
127 };
128 35
129 // Specialization of DefaultDeleter for array types. 36 // These used to convert between rtc::scoped_ptr and std::unique_ptr. Now they
130 template <class T> 37 // are no-ops.
131 struct DefaultDeleter<T[]> {
132 inline void operator()(T* ptr) const {
133 enum { type_must_be_complete = sizeof(T) };
134 delete[] ptr;
135 }
136
137 private:
138 // Disable this operator for any U != T because it is undefined to execute
139 // an array delete when the static type of the array mismatches the dynamic
140 // type.
141 //
142 // References:
143 // C++98 [expr.delete]p3
144 // http://cplusplus.github.com/LWG/lwg-defects.html#938
145 template <typename U> void operator()(U* array) const;
146 };
147
148 template <class T, int n>
149 struct DefaultDeleter<T[n]> {
150 // Never allow someone to declare something like scoped_ptr<int[10]>.
151 static_assert(sizeof(T) == -1, "do not use array with size as type");
152 };
153
154 // Function object which invokes 'free' on its parameter, which must be
155 // a pointer. Can be used to store malloc-allocated pointers in scoped_ptr:
156 //
157 // scoped_ptr<int, rtc::FreeDeleter> foo_ptr(
158 // static_cast<int*>(malloc(sizeof(int))));
159 struct FreeDeleter {
160 inline void operator()(void* ptr) const {
161 free(ptr);
162 }
163 };
164
165 namespace internal {
166
167 template <typename T> 38 template <typename T>
168 struct ShouldAbortOnSelfReset { 39 std::unique_ptr<T> ScopedToUnique(std::unique_ptr<T> up) {
169 template <typename U> 40 return up;
170 static rtc::internal::NoType Test(const typename U::AllowSelfReset*);
171
172 template <typename U>
173 static rtc::internal::YesType Test(...);
174
175 static const bool value =
176 sizeof(Test<T>(0)) == sizeof(rtc::internal::YesType);
177 };
178
179 // Minimal implementation of the core logic of scoped_ptr, suitable for
180 // reuse in both scoped_ptr and its specializations.
181 template <class T, class D>
182 class scoped_ptr_impl {
183 public:
184 explicit scoped_ptr_impl(T* p) : data_(p) {}
185
186 // Initializer for deleters that have data parameters.
187 scoped_ptr_impl(T* p, const D& d) : data_(p, d) {}
188
189 // Templated constructor that destructively takes the value from another
190 // scoped_ptr_impl.
191 template <typename U, typename V>
192 scoped_ptr_impl(scoped_ptr_impl<U, V>* other)
193 : data_(other->release(), other->get_deleter()) {
194 // We do not support move-only deleters. We could modify our move
195 // emulation to have rtc::subtle::move() and rtc::subtle::forward()
196 // functions that are imperfect emulations of their C++11 equivalents,
197 // but until there's a requirement, just assume deleters are copyable.
198 }
199
200 template <typename U, typename V>
201 void TakeState(scoped_ptr_impl<U, V>* other) {
202 // See comment in templated constructor above regarding lack of support
203 // for move-only deleters.
204 reset(other->release());
205 get_deleter() = other->get_deleter();
206 }
207
208 ~scoped_ptr_impl() {
209 if (data_.ptr != nullptr) {
210 // Not using get_deleter() saves one function call in non-optimized
211 // builds.
212 static_cast<D&>(data_)(data_.ptr);
213 }
214 }
215
216 void reset(T* p) {
217 // This is a self-reset, which is no longer allowed for default deleters:
218 // https://crbug.com/162971
219 assert(!ShouldAbortOnSelfReset<D>::value || p == nullptr || p != data_.ptr);
220
221 // Note that running data_.ptr = p can lead to undefined behavior if
222 // get_deleter()(get()) deletes this. In order to prevent this, reset()
223 // should update the stored pointer before deleting its old value.
224 //
225 // However, changing reset() to use that behavior may cause current code to
226 // break in unexpected ways. If the destruction of the owned object
227 // dereferences the scoped_ptr when it is destroyed by a call to reset(),
228 // then it will incorrectly dispatch calls to |p| rather than the original
229 // value of |data_.ptr|.
230 //
231 // During the transition period, set the stored pointer to nullptr while
232 // deleting the object. Eventually, this safety check will be removed to
233 // prevent the scenario initially described from occurring and
234 // http://crbug.com/176091 can be closed.
235 T* old = data_.ptr;
236 data_.ptr = nullptr;
237 if (old != nullptr)
238 static_cast<D&>(data_)(old);
239 data_.ptr = p;
240 }
241
242 T* get() const { return data_.ptr; }
243
244 D& get_deleter() { return data_; }
245 const D& get_deleter() const { return data_; }
246
247 void swap(scoped_ptr_impl& p2) {
248 // Standard swap idiom: 'using std::swap' ensures that std::swap is
249 // present in the overload set, but we call swap unqualified so that
250 // any more-specific overloads can be used, if available.
251 using std::swap;
252 swap(static_cast<D&>(data_), static_cast<D&>(p2.data_));
253 swap(data_.ptr, p2.data_.ptr);
254 }
255
256 T* release() {
257 T* old_ptr = data_.ptr;
258 data_.ptr = nullptr;
259 return old_ptr;
260 }
261
262 T** accept() {
263 reset(nullptr);
264 return &(data_.ptr);
265 }
266
267 T** use() {
268 return &(data_.ptr);
269 }
270
271 private:
272 // Needed to allow type-converting constructor.
273 template <typename U, typename V> friend class scoped_ptr_impl;
274
275 // Use the empty base class optimization to allow us to have a D
276 // member, while avoiding any space overhead for it when D is an
277 // empty class. See e.g. http://www.cantrip.org/emptyopt.html for a good
278 // discussion of this technique.
279 struct Data : public D {
280 explicit Data(T* ptr_in) : ptr(ptr_in) {}
281 Data(T* ptr_in, const D& other) : D(other), ptr(ptr_in) {}
282 T* ptr;
283 };
284
285 Data data_;
286
287 RTC_DISALLOW_COPY_AND_ASSIGN(scoped_ptr_impl);
288 };
289
290 } // namespace internal
291
292 // A scoped_ptr<T> is like a T*, except that the destructor of scoped_ptr<T>
293 // automatically deletes the pointer it holds (if any).
294 // That is, scoped_ptr<T> owns the T object that it points to.
295 // Like a T*, a scoped_ptr<T> may hold either nullptr or a pointer to a T
296 // object. Also like T*, scoped_ptr<T> is thread-compatible, and once you
297 // dereference it, you get the thread safety guarantees of T.
298 //
299 // The size of scoped_ptr is small. On most compilers, when using the
300 // DefaultDeleter, sizeof(scoped_ptr<T>) == sizeof(T*). Custom deleters will
301 // increase the size proportional to whatever state they need to have. See
302 // comments inside scoped_ptr_impl<> for details.
303 //
304 // Current implementation targets having a strict subset of C++11's
305 // unique_ptr<> features. Known deficiencies include not supporting move-only
306 // deleters, function pointers as deleters, and deleters with reference
307 // types.
308 template <class T, class D = rtc::DefaultDeleter<T> >
309 class scoped_ptr {
310
311 // TODO(ajm): If we ever import RefCountedBase, this check needs to be
312 // enabled.
313 //static_assert(rtc::internal::IsNotRefCounted<T>::value,
314 // "T is refcounted type and needs scoped refptr");
315
316 public:
317 // The element and deleter types.
318 typedef T element_type;
319 typedef D deleter_type;
320
321 // Constructor. Defaults to initializing with nullptr.
322 scoped_ptr() : impl_(nullptr) {}
323
324 // Constructor. Takes ownership of p.
325 explicit scoped_ptr(element_type* p) : impl_(p) {}
326
327 // Constructor. Allows initialization of a stateful deleter.
328 scoped_ptr(element_type* p, const D& d) : impl_(p, d) {}
329
330 // Constructor. Allows construction from a nullptr.
331 scoped_ptr(std::nullptr_t) : impl_(nullptr) {}
332
333 // Constructor. Allows construction from a scoped_ptr rvalue for a
334 // convertible type and deleter.
335 //
336 // IMPLEMENTATION NOTE: C++11 unique_ptr<> keeps this constructor distinct
337 // from the normal move constructor. By C++11 20.7.1.2.1.21, this constructor
338 // has different post-conditions if D is a reference type. Since this
339 // implementation does not support deleters with reference type,
340 // we do not need a separate move constructor allowing us to avoid one
341 // use of SFINAE. You only need to care about this if you modify the
342 // implementation of scoped_ptr.
343 template <typename U, typename V>
344 scoped_ptr(scoped_ptr<U, V>&& other)
345 : impl_(&other.impl_) {
346 static_assert(!rtc::is_array<U>::value, "U cannot be an array");
347 }
348
349 // operator=. Allows assignment from a scoped_ptr rvalue for a convertible
350 // type and deleter.
351 //
352 // IMPLEMENTATION NOTE: C++11 unique_ptr<> keeps this operator= distinct from
353 // the normal move assignment operator. By C++11 20.7.1.2.3.4, this templated
354 // form has different requirements on for move-only Deleters. Since this
355 // implementation does not support move-only Deleters, we do not need a
356 // separate move assignment operator allowing us to avoid one use of SFINAE.
357 // You only need to care about this if you modify the implementation of
358 // scoped_ptr.
359 template <typename U, typename V>
360 scoped_ptr& operator=(scoped_ptr<U, V>&& rhs) {
361 static_assert(!rtc::is_array<U>::value, "U cannot be an array");
362 impl_.TakeState(&rhs.impl_);
363 return *this;
364 }
365
366 // operator=. Allows assignment from a nullptr. Deletes the currently owned
367 // object, if any.
368 scoped_ptr& operator=(std::nullptr_t) {
369 reset();
370 return *this;
371 }
372
373 // Deleted copy constructor and copy assignment, to make the type move-only.
374 scoped_ptr(const scoped_ptr& other) = delete;
375 scoped_ptr& operator=(const scoped_ptr& other) = delete;
376
377 // Reset. Deletes the currently owned object, if any.
378 // Then takes ownership of a new object, if given.
379 void reset(element_type* p = nullptr) { impl_.reset(p); }
380
381 // Accessors to get the owned object.
382 // operator* and operator-> will assert() if there is no current object.
383 element_type& operator*() const {
384 assert(impl_.get() != nullptr);
385 return *impl_.get();
386 }
387 element_type* operator->() const {
388 assert(impl_.get() != nullptr);
389 return impl_.get();
390 }
391 element_type* get() const { return impl_.get(); }
392
393 // Access to the deleter.
394 deleter_type& get_deleter() { return impl_.get_deleter(); }
395 const deleter_type& get_deleter() const { return impl_.get_deleter(); }
396
397 // Allow scoped_ptr<element_type> to be used in boolean expressions, but not
398 // implicitly convertible to a real bool (which is dangerous).
399 //
400 // Note that this trick is only safe when the == and != operators
401 // are declared explicitly, as otherwise "scoped_ptr1 ==
402 // scoped_ptr2" will compile but do the wrong thing (i.e., convert
403 // to Testable and then do the comparison).
404 private:
405 typedef rtc::internal::scoped_ptr_impl<element_type, deleter_type>
406 scoped_ptr::*Testable;
407
408 public:
409 operator Testable() const {
410 return impl_.get() ? &scoped_ptr::impl_ : nullptr;
411 }
412
413 // Comparison operators.
414 // These return whether two scoped_ptr refer to the same object, not just to
415 // two different but equal objects.
416 bool operator==(const element_type* p) const { return impl_.get() == p; }
417 bool operator!=(const element_type* p) const { return impl_.get() != p; }
418
419 // Swap two scoped pointers.
420 void swap(scoped_ptr& p2) {
421 impl_.swap(p2.impl_);
422 }
423
424 // Release a pointer.
425 // The return value is the current pointer held by this object. If this object
426 // holds a nullptr, the return value is nullptr. After this operation, this
427 // object will hold a nullptr, and will not own the object any more.
428 element_type* release() WARN_UNUSED_RESULT {
429 return impl_.release();
430 }
431
432 // Delete the currently held pointer and return a pointer
433 // to allow overwriting of the current pointer address.
434 element_type** accept() WARN_UNUSED_RESULT {
435 return impl_.accept();
436 }
437
438 // Return a pointer to the current pointer address.
439 element_type** use() WARN_UNUSED_RESULT {
440 return impl_.use();
441 }
442
443 private:
444 // Needed to reach into |impl_| in the constructor.
445 template <typename U, typename V> friend class scoped_ptr;
446 rtc::internal::scoped_ptr_impl<element_type, deleter_type> impl_;
447
448 // Forbidden for API compatibility with std::unique_ptr.
449 explicit scoped_ptr(int disallow_construction_from_null);
450
451 // Forbid comparison of scoped_ptr types. If U != T, it totally
452 // doesn't make sense, and if U == T, it still doesn't make sense
453 // because you should never have the same object owned by two different
454 // scoped_ptrs.
455 template <class U> bool operator==(scoped_ptr<U> const& p2) const;
456 template <class U> bool operator!=(scoped_ptr<U> const& p2) const;
457 };
458
459 template <class T, class D>
460 class scoped_ptr<T[], D> {
461 public:
462 // The element and deleter types.
463 typedef T element_type;
464 typedef D deleter_type;
465
466 // Constructor. Defaults to initializing with nullptr.
467 scoped_ptr() : impl_(nullptr) {}
468
469 // Constructor. Stores the given array. Note that the argument's type
470 // must exactly match T*. In particular:
471 // - it cannot be a pointer to a type derived from T, because it is
472 // inherently unsafe in the general case to access an array through a
473 // pointer whose dynamic type does not match its static type (eg., if
474 // T and the derived types had different sizes access would be
475 // incorrectly calculated). Deletion is also always undefined
476 // (C++98 [expr.delete]p3). If you're doing this, fix your code.
477 // - it cannot be const-qualified differently from T per unique_ptr spec
478 // (http://cplusplus.github.com/LWG/lwg-active.html#2118). Users wanting
479 // to work around this may use implicit_cast<const T*>().
480 // However, because of the first bullet in this comment, users MUST
481 // NOT use implicit_cast<Base*>() to upcast the static type of the array.
482 explicit scoped_ptr(element_type* array) : impl_(array) {}
483
484 // Constructor. Allows construction from a nullptr.
485 scoped_ptr(std::nullptr_t) : impl_(nullptr) {}
486
487 // Constructor. Allows construction from a scoped_ptr rvalue.
488 scoped_ptr(scoped_ptr&& other) : impl_(&other.impl_) {}
489
490 // operator=. Allows assignment from a scoped_ptr rvalue.
491 scoped_ptr& operator=(scoped_ptr&& rhs) {
492 impl_.TakeState(&rhs.impl_);
493 return *this;
494 }
495
496 // operator=. Allows assignment from a nullptr. Deletes the currently owned
497 // array, if any.
498 scoped_ptr& operator=(std::nullptr_t) {
499 reset();
500 return *this;
501 }
502
503 // Deleted copy constructor and copy assignment, to make the type move-only.
504 scoped_ptr(const scoped_ptr& other) = delete;
505 scoped_ptr& operator=(const scoped_ptr& other) = delete;
506
507 // Reset. Deletes the currently owned array, if any.
508 // Then takes ownership of a new object, if given.
509 void reset(element_type* array = nullptr) { impl_.reset(array); }
510
511 // Accessors to get the owned array.
512 element_type& operator[](size_t i) const {
513 assert(impl_.get() != nullptr);
514 return impl_.get()[i];
515 }
516 element_type* get() const { return impl_.get(); }
517
518 // Access to the deleter.
519 deleter_type& get_deleter() { return impl_.get_deleter(); }
520 const deleter_type& get_deleter() const { return impl_.get_deleter(); }
521
522 // Allow scoped_ptr<element_type> to be used in boolean expressions, but not
523 // implicitly convertible to a real bool (which is dangerous).
524 private:
525 typedef rtc::internal::scoped_ptr_impl<element_type, deleter_type>
526 scoped_ptr::*Testable;
527
528 public:
529 operator Testable() const {
530 return impl_.get() ? &scoped_ptr::impl_ : nullptr;
531 }
532
533 // Comparison operators.
534 // These return whether two scoped_ptr refer to the same object, not just to
535 // two different but equal objects.
536 bool operator==(element_type* array) const { return impl_.get() == array; }
537 bool operator!=(element_type* array) const { return impl_.get() != array; }
538
539 // Swap two scoped pointers.
540 void swap(scoped_ptr& p2) {
541 impl_.swap(p2.impl_);
542 }
543
544 // Release a pointer.
545 // The return value is the current pointer held by this object. If this object
546 // holds a nullptr, the return value is nullptr. After this operation, this
547 // object will hold a nullptr, and will not own the object any more.
548 element_type* release() WARN_UNUSED_RESULT {
549 return impl_.release();
550 }
551
552 // Delete the currently held pointer and return a pointer
553 // to allow overwriting of the current pointer address.
554 element_type** accept() WARN_UNUSED_RESULT {
555 return impl_.accept();
556 }
557
558 // Return a pointer to the current pointer address.
559 element_type** use() WARN_UNUSED_RESULT {
560 return impl_.use();
561 }
562
563 private:
564 // Force element_type to be a complete type.
565 enum { type_must_be_complete = sizeof(element_type) };
566
567 // Actually hold the data.
568 rtc::internal::scoped_ptr_impl<element_type, deleter_type> impl_;
569
570 // Disable initialization from any type other than element_type*, by
571 // providing a constructor that matches such an initialization, but is
572 // private and has no definition. This is disabled because it is not safe to
573 // call delete[] on an array whose static type does not match its dynamic
574 // type.
575 template <typename U> explicit scoped_ptr(U* array);
576 explicit scoped_ptr(int disallow_construction_from_null);
577
578 // Disable reset() from any type other than element_type*, for the same
579 // reasons as the constructor above.
580 template <typename U> void reset(U* array);
581 void reset(int disallow_reset_from_null);
582
583 // Forbid comparison of scoped_ptr types. If U != T, it totally
584 // doesn't make sense, and if U == T, it still doesn't make sense
585 // because you should never have the same object owned by two different
586 // scoped_ptrs.
587 template <class U> bool operator==(scoped_ptr<U> const& p2) const;
588 template <class U> bool operator!=(scoped_ptr<U> const& p2) const;
589 };
590
591 template <class T, class D>
592 void swap(rtc::scoped_ptr<T, D>& p1, rtc::scoped_ptr<T, D>& p2) {
593 p1.swap(p2);
594 }
595
596 // Convert between the most common kinds of scoped_ptr and unique_ptr.
597 template <typename T>
598 std::unique_ptr<T> ScopedToUnique(scoped_ptr<T> sp) {
599 return std::unique_ptr<T>(sp.release());
600 } 41 }
601 template <typename T> 42 template <typename T>
602 scoped_ptr<T> UniqueToScoped(std::unique_ptr<T> up) { 43 std::unique_ptr<T> UniqueToScoped(std::unique_ptr<T> up) {
603 return scoped_ptr<T>(up.release()); 44 return up;
604 } 45 }
605 46
606 } // namespace rtc 47 } // namespace rtc
607 48
608 template <class T, class D>
609 bool operator==(T* p1, const rtc::scoped_ptr<T, D>& p2) {
610 return p1 == p2.get();
611 }
612
613 template <class T, class D>
614 bool operator!=(T* p1, const rtc::scoped_ptr<T, D>& p2) {
615 return p1 != p2.get();
616 }
617
618 // A function to convert T* into scoped_ptr<T>
619 // Doing e.g. make_scoped_ptr(new FooBarBaz<type>(arg)) is a shorter notation
620 // for scoped_ptr<FooBarBaz<type> >(new FooBarBaz<type>(arg))
621 template <typename T>
622 rtc::scoped_ptr<T> rtc_make_scoped_ptr(T* ptr) {
623 return rtc::scoped_ptr<T>(ptr);
624 }
625
626 #endif // #ifndef WEBRTC_BASE_SCOPED_PTR_H__ 49 #endif // #ifndef WEBRTC_BASE_SCOPED_PTR_H__
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