| OLD | NEW |
| 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__ |
| OLD | NEW |