The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 2 | * Copyright (C) 2016 The Android Open Source Project |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 17 | |
| 18 | // SOME COMMENTS ABOUT USAGE: |
| 19 | |
| 20 | // This provides primarily wp<> weak pointer types and RefBase, which work |
| 21 | // together with sp<> from <StrongPointer.h>. |
| 22 | |
| 23 | // sp<> (and wp<>) are a type of smart pointer that use a well defined protocol |
| 24 | // to operate. As long as the object they are templated with implements that |
| 25 | // protocol, these smart pointers work. In several places the platform |
| 26 | // instantiates sp<> with non-RefBase objects; the two are not tied to each |
| 27 | // other. |
| 28 | |
| 29 | // RefBase is such an implementation and it supports strong pointers, weak |
| 30 | // pointers and some magic features for the binder. |
| 31 | |
| 32 | // So, when using RefBase objects, you have the ability to use strong and weak |
| 33 | // pointers through sp<> and wp<>. |
| 34 | |
| 35 | // Normally, when the last strong pointer goes away, the object is destroyed, |
| 36 | // i.e. it's destructor is called. HOWEVER, parts of its associated memory is not |
| 37 | // freed until the last weak pointer is released. |
| 38 | |
| 39 | // Weak pointers are essentially "safe" pointers. They are always safe to |
| 40 | // access through promote(). They may return nullptr if the object was |
| 41 | // destroyed because it ran out of strong pointers. This makes them good candidates |
| 42 | // for keys in a cache for instance. |
| 43 | |
| 44 | // Weak pointers remain valid for comparison purposes even after the underlying |
| 45 | // object has been destroyed. Even if object A is destroyed and its memory reused |
| 46 | // for B, A remaining weak pointer to A will not compare equal to one to B. |
| 47 | // This again makes them attractive for use as keys. |
| 48 | |
| 49 | // How is this supposed / intended to be used? |
| 50 | |
| 51 | // Our recommendation is to use strong references (sp<>) when there is an |
| 52 | // ownership relation. e.g. when an object "owns" another one, use a strong |
| 53 | // ref. And of course use strong refs as arguments of functions (it's extremely |
| 54 | // rare that a function will take a wp<>). |
| 55 | |
| 56 | // Typically a newly allocated object will immediately be used to initialize |
| 57 | // a strong pointer, which may then be used to construct or assign to other |
| 58 | // strong and weak pointers. |
| 59 | |
| 60 | // Use weak references when there are no ownership relation. e.g. the keys in a |
| 61 | // cache (you cannot use plain pointers because there is no safe way to acquire |
| 62 | // a strong reference from a vanilla pointer). |
| 63 | |
| 64 | // This implies that two objects should never (or very rarely) have sp<> on |
| 65 | // each other, because they can't both own each other. |
| 66 | |
| 67 | |
| 68 | // Caveats with reference counting |
| 69 | |
| 70 | // Obviously, circular strong references are a big problem; this creates leaks |
| 71 | // and it's hard to debug -- except it's in fact really easy because RefBase has |
| 72 | // tons of debugging code for that. It can basically tell you exactly where the |
| 73 | // leak is. |
| 74 | |
| 75 | // Another problem has to do with destructors with side effects. You must |
| 76 | // assume that the destructor of reference counted objects can be called AT ANY |
| 77 | // TIME. For instance code as simple as this: |
| 78 | |
| 79 | // void setStuff(const sp<Stuff>& stuff) { |
| 80 | // std::lock_guard<std::mutex> lock(mMutex); |
| 81 | // mStuff = stuff; |
| 82 | // } |
| 83 | |
| 84 | // is very dangerous. This code WILL deadlock one day or another. |
| 85 | |
| 86 | // What isn't obvious is that ~Stuff() can be called as a result of the |
| 87 | // assignment. And it gets called with the lock held. First of all, the lock is |
| 88 | // protecting mStuff, not ~Stuff(). Secondly, if ~Stuff() uses its own internal |
| 89 | // mutex, now you have mutex ordering issues. Even worse, if ~Stuff() is |
| 90 | // virtual, now you're calling into "user" code (potentially), by that, I mean, |
| 91 | // code you didn't even write. |
| 92 | |
| 93 | // A correct way to write this code is something like: |
| 94 | |
| 95 | // void setStuff(const sp<Stuff>& stuff) { |
| 96 | // std::unique_lock<std::mutex> lock(mMutex); |
| 97 | // sp<Stuff> hold = mStuff; |
| 98 | // mStuff = stuff; |
| 99 | // lock.unlock(); |
| 100 | // } |
| 101 | |
| 102 | // More importantly, reference counted objects should do as little work as |
| 103 | // possible in their destructor, or at least be mindful that their destructor |
| 104 | // could be called from very weird and unintended places. |
| 105 | |
| 106 | // Other more specific restrictions for wp<> and sp<>: |
| 107 | |
Hans Boehm | 23c857e | 2016-08-02 18:39:30 -0700 | [diff] [blame] | 108 | // Do not construct a strong pointer to "this" in an object's constructor. |
| 109 | // The onFirstRef() callback would be made on an incompletely constructed |
| 110 | // object. |
| 111 | // Construction of a weak pointer to "this" in an object's constructor is also |
| 112 | // discouraged. But the implementation was recently changed so that, in the |
| 113 | // absence of extendObjectLifetime() calls, weak pointers no longer impact |
| 114 | // object lifetime, and hence this no longer risks premature deallocation, |
| 115 | // and hence usually works correctly. |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 116 | |
| 117 | // Such strong or weak pointers can be safely created in the RefBase onFirstRef() |
| 118 | // callback. |
| 119 | |
| 120 | // Use of wp::unsafe_get() for any purpose other than debugging is almost |
| 121 | // always wrong. Unless you somehow know that there is a longer-lived sp<> to |
| 122 | // the same object, it may well return a pointer to a deallocated object that |
| 123 | // has since been reallocated for a different purpose. (And if you know there |
| 124 | // is a longer-lived sp<>, why not use an sp<> directly?) A wp<> should only be |
| 125 | // dereferenced by using promote(). |
| 126 | |
Hans Boehm | 23c857e | 2016-08-02 18:39:30 -0700 | [diff] [blame] | 127 | // Any object inheriting from RefBase should always be destroyed as the result |
| 128 | // of a reference count decrement, not via any other means. Such objects |
| 129 | // should never be stack allocated, or appear directly as data members in other |
| 130 | // objects. Objects inheriting from RefBase should have their strong reference |
| 131 | // count incremented as soon as possible after construction. Usually this |
| 132 | // will be done via construction of an sp<> to the object, but may instead |
| 133 | // involve other means of calling RefBase::incStrong(). |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 134 | // Explicitly deleting or otherwise destroying a RefBase object with outstanding |
Hans Boehm | 23c857e | 2016-08-02 18:39:30 -0700 | [diff] [blame] | 135 | // wp<> or sp<> pointers to it will result in an abort or heap corruption. |
| 136 | |
| 137 | // It is particularly important not to mix sp<> and direct storage management |
| 138 | // since the sp from raw pointer constructor is implicit. Thus if a RefBase- |
| 139 | // -derived object of type T is managed without ever incrementing its strong |
| 140 | // count, and accidentally passed to f(sp<T>), a strong pointer to the object |
| 141 | // will be temporarily constructed and destroyed, prematurely deallocating the |
| 142 | // object, and resulting in heap corruption. None of this would be easily |
| 143 | // visible in the source. |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 144 | |
| 145 | // Extra Features: |
| 146 | |
| 147 | // RefBase::extendObjectLifetime() can be used to prevent destruction of the |
| 148 | // object while there are still weak references. This is really special purpose |
| 149 | // functionality to support Binder. |
| 150 | |
| 151 | // Wp::promote(), implemented via the attemptIncStrong() member function, is |
| 152 | // used to try to convert a weak pointer back to a strong pointer. It's the |
| 153 | // normal way to try to access the fields of an object referenced only through |
| 154 | // a wp<>. Binder code also sometimes uses attemptIncStrong() directly. |
| 155 | |
| 156 | // RefBase provides a number of additional callbacks for certain reference count |
| 157 | // events, as well as some debugging facilities. |
| 158 | |
| 159 | // Debugging support can be enabled by turning on DEBUG_REFS in RefBase.cpp. |
Hans Boehm | 23c857e | 2016-08-02 18:39:30 -0700 | [diff] [blame] | 160 | // Otherwise little checking is provided. |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 161 | |
| 162 | // Thread safety: |
| 163 | |
| 164 | // Like std::shared_ptr, sp<> and wp<> allow concurrent accesses to DIFFERENT |
| 165 | // sp<> and wp<> instances that happen to refer to the same underlying object. |
| 166 | // They do NOT support concurrent access (where at least one access is a write) |
| 167 | // to THE SAME sp<> or wp<>. In effect, their thread-safety properties are |
| 168 | // exactly like those of T*, NOT atomic<T*>. |
| 169 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 170 | #ifndef ANDROID_REF_BASE_H |
| 171 | #define ANDROID_REF_BASE_H |
| 172 | |
Hans Boehm | e263e6c | 2016-05-11 18:15:12 -0700 | [diff] [blame] | 173 | #include <atomic> |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 174 | |
| 175 | #include <stdint.h> |
| 176 | #include <sys/types.h> |
| 177 | #include <stdlib.h> |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 178 | #include <string.h> |
| 179 | |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 180 | // LightRefBase used to be declared in this header, so we have to include it |
| 181 | #include <utils/LightRefBase.h> |
| 182 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 183 | #include <utils/StrongPointer.h> |
Jeff Brown | 9a0a76d | 2012-03-16 14:45:49 -0700 | [diff] [blame] | 184 | #include <utils/TypeHelpers.h> |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 185 | |
| 186 | // --------------------------------------------------------------------------- |
| 187 | namespace android { |
| 188 | |
Mathias Agopian | 84a23fa | 2011-02-16 15:23:08 -0800 | [diff] [blame] | 189 | class TextOutput; |
Mathias Agopian | 84a23fa | 2011-02-16 15:23:08 -0800 | [diff] [blame] | 190 | TextOutput& printWeakPointer(TextOutput& to, const void* val); |
| 191 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 192 | // --------------------------------------------------------------------------- |
| 193 | |
Mathias Agopian | ff49de7 | 2011-02-09 18:38:55 -0800 | [diff] [blame] | 194 | #define COMPARE_WEAK(_op_) \ |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 195 | inline bool operator _op_ (const sp<T>& o) const { \ |
| 196 | return m_ptr _op_ o.m_ptr; \ |
| 197 | } \ |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 198 | inline bool operator _op_ (const T* o) const { \ |
| 199 | return m_ptr _op_ o; \ |
| 200 | } \ |
| 201 | template<typename U> \ |
| 202 | inline bool operator _op_ (const sp<U>& o) const { \ |
| 203 | return m_ptr _op_ o.m_ptr; \ |
| 204 | } \ |
| 205 | template<typename U> \ |
Mathias Agopian | ff49de7 | 2011-02-09 18:38:55 -0800 | [diff] [blame] | 206 | inline bool operator _op_ (const U* o) const { \ |
| 207 | return m_ptr _op_ o; \ |
| 208 | } |
| 209 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 210 | // --------------------------------------------------------------------------- |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 211 | |
Colin Cross | 1811d15 | 2016-09-26 14:24:48 -0700 | [diff] [blame] | 212 | // RefererenceRenamer is pure abstract, there is no virtual method |
| 213 | // implementation to put in a translation unit in order to silence the |
| 214 | // weak vtables warning. |
| 215 | #if defined(__clang__) |
| 216 | #pragma clang diagnostic push |
| 217 | #pragma clang diagnostic ignored "-Wweak-vtables" |
| 218 | #endif |
| 219 | |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 220 | class ReferenceRenamer { |
| 221 | protected: |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 222 | // destructor is purposely not virtual so we avoid code overhead from |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 223 | // subclasses; we have to make it protected to guarantee that it |
| 224 | // cannot be called from this base class (and to make strict compilers |
| 225 | // happy). |
Colin Cross | 1811d15 | 2016-09-26 14:24:48 -0700 | [diff] [blame] | 226 | ~ReferenceRenamer() { } |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 227 | public: |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 228 | virtual void operator()(size_t i) const = 0; |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 229 | }; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 230 | |
Colin Cross | 1811d15 | 2016-09-26 14:24:48 -0700 | [diff] [blame] | 231 | #if defined(__clang__) |
| 232 | #pragma clang diagnostic pop |
| 233 | #endif |
| 234 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 235 | // --------------------------------------------------------------------------- |
| 236 | |
| 237 | class RefBase |
| 238 | { |
| 239 | public: |
| 240 | void incStrong(const void* id) const; |
| 241 | void decStrong(const void* id) const; |
| 242 | |
| 243 | void forceIncStrong(const void* id) const; |
| 244 | |
| 245 | //! DEBUGGING ONLY: Get current strong ref count. |
| 246 | int32_t getStrongCount() const; |
| 247 | |
| 248 | class weakref_type |
| 249 | { |
| 250 | public: |
| 251 | RefBase* refBase() const; |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 252 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 253 | void incWeak(const void* id); |
| 254 | void decWeak(const void* id); |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 255 | |
Mathias Agopian | ad09965 | 2011-08-10 21:07:02 -0700 | [diff] [blame] | 256 | // acquires a strong reference if there is already one. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 257 | bool attemptIncStrong(const void* id); |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 258 | |
Mathias Agopian | ad09965 | 2011-08-10 21:07:02 -0700 | [diff] [blame] | 259 | // acquires a weak reference if there is already one. |
| 260 | // This is not always safe. see ProcessState.cpp and BpBinder.cpp |
| 261 | // for proper use. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 262 | bool attemptIncWeak(const void* id); |
| 263 | |
| 264 | //! DEBUGGING ONLY: Get current weak ref count. |
| 265 | int32_t getWeakCount() const; |
| 266 | |
| 267 | //! DEBUGGING ONLY: Print references held on object. |
| 268 | void printRefs() const; |
| 269 | |
| 270 | //! DEBUGGING ONLY: Enable tracking for this object. |
| 271 | // enable -- enable/disable tracking |
| 272 | // retain -- when tracking is enable, if true, then we save a stack trace |
| 273 | // for each reference and dereference; when retain == false, we |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 274 | // match up references and dereferences and keep only the |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 275 | // outstanding ones. |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 276 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 277 | void trackMe(bool enable, bool retain); |
| 278 | }; |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 279 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 280 | weakref_type* createWeak(const void* id) const; |
| 281 | |
| 282 | weakref_type* getWeakRefs() const; |
| 283 | |
| 284 | //! DEBUGGING ONLY: Print references held on object. |
| 285 | inline void printRefs() const { getWeakRefs()->printRefs(); } |
| 286 | |
| 287 | //! DEBUGGING ONLY: Enable tracking of object. |
| 288 | inline void trackMe(bool enable, bool retain) |
| 289 | { |
| 290 | getWeakRefs()->trackMe(enable, retain); |
| 291 | } |
| 292 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 293 | typedef RefBase basetype; |
| 294 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 295 | protected: |
| 296 | RefBase(); |
| 297 | virtual ~RefBase(); |
Mathias Agopian | 7f57eac | 2011-06-16 17:15:51 -0700 | [diff] [blame] | 298 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 299 | //! Flags for extendObjectLifetime() |
| 300 | enum { |
Mathias Agopian | ad09965 | 2011-08-10 21:07:02 -0700 | [diff] [blame] | 301 | OBJECT_LIFETIME_STRONG = 0x0000, |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 302 | OBJECT_LIFETIME_WEAK = 0x0001, |
Mathias Agopian | ad09965 | 2011-08-10 21:07:02 -0700 | [diff] [blame] | 303 | OBJECT_LIFETIME_MASK = 0x0001 |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 304 | }; |
| 305 | |
| 306 | void extendObjectLifetime(int32_t mode); |
| 307 | |
| 308 | //! Flags for onIncStrongAttempted() |
| 309 | enum { |
| 310 | FIRST_INC_STRONG = 0x0001 |
| 311 | }; |
| 312 | |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 313 | // Invoked after creation of initial strong pointer/reference. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 314 | virtual void onFirstRef(); |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 315 | // Invoked when either the last strong reference goes away, or we need to undo |
| 316 | // the effect of an unnecessary onIncStrongAttempted. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 317 | virtual void onLastStrongRef(const void* id); |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 318 | // Only called in OBJECT_LIFETIME_WEAK case. Returns true if OK to promote to |
| 319 | // strong reference. May have side effects if it returns true. |
| 320 | // The first flags argument is always FIRST_INC_STRONG. |
| 321 | // TODO: Remove initial flag argument. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 322 | virtual bool onIncStrongAttempted(uint32_t flags, const void* id); |
Hans Boehm | 9ba7192 | 2016-07-21 18:56:55 -0700 | [diff] [blame] | 323 | // Invoked in the OBJECT_LIFETIME_WEAK case when the last reference of either |
| 324 | // kind goes away. Unused. |
| 325 | // TODO: Remove. |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 326 | virtual void onLastWeakRef(const void* id); |
| 327 | |
| 328 | private: |
| 329 | friend class weakref_type; |
| 330 | class weakref_impl; |
| 331 | |
| 332 | RefBase(const RefBase& o); |
| 333 | RefBase& operator=(const RefBase& o); |
Mathias Agopian | ad09965 | 2011-08-10 21:07:02 -0700 | [diff] [blame] | 334 | |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 335 | private: |
| 336 | friend class ReferenceMover; |
| 337 | |
| 338 | static void renameRefs(size_t n, const ReferenceRenamer& renamer); |
| 339 | |
| 340 | static void renameRefId(weakref_type* ref, |
| 341 | const void* old_id, const void* new_id); |
| 342 | |
| 343 | static void renameRefId(RefBase* ref, |
| 344 | const void* old_id, const void* new_id); |
| 345 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 346 | weakref_impl* const mRefs; |
| 347 | }; |
| 348 | |
| 349 | // --------------------------------------------------------------------------- |
| 350 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 351 | template <typename T> |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 352 | class wp |
| 353 | { |
| 354 | public: |
| 355 | typedef typename RefBase::weakref_type weakref_type; |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 356 | |
Yi Kong | c1a1562 | 2018-07-11 17:37:34 -0700 | [diff] [blame] | 357 | inline wp() : m_ptr(nullptr) { } |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 358 | |
Chih-Hung Hsieh | 2a92996 | 2016-08-02 12:14:47 -0700 | [diff] [blame] | 359 | wp(T* other); // NOLINT(implicit) |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 360 | wp(const wp<T>& other); |
Chih-Hung Hsieh | 2a92996 | 2016-08-02 12:14:47 -0700 | [diff] [blame] | 361 | explicit wp(const sp<T>& other); |
| 362 | template<typename U> wp(U* other); // NOLINT(implicit) |
| 363 | template<typename U> wp(const sp<U>& other); // NOLINT(implicit) |
| 364 | template<typename U> wp(const wp<U>& other); // NOLINT(implicit) |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 365 | |
| 366 | ~wp(); |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 367 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 368 | // Assignment |
| 369 | |
| 370 | wp& operator = (T* other); |
| 371 | wp& operator = (const wp<T>& other); |
| 372 | wp& operator = (const sp<T>& other); |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 373 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 374 | template<typename U> wp& operator = (U* other); |
| 375 | template<typename U> wp& operator = (const wp<U>& other); |
| 376 | template<typename U> wp& operator = (const sp<U>& other); |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 377 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 378 | void set_object_and_refs(T* other, weakref_type* refs); |
| 379 | |
| 380 | // promotion to sp |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 381 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 382 | sp<T> promote() const; |
| 383 | |
| 384 | // Reset |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 385 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 386 | void clear(); |
| 387 | |
| 388 | // Accessors |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 389 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 390 | inline weakref_type* get_refs() const { return m_refs; } |
Mathias Agopian | 44cee05 | 2017-03-27 17:59:01 -0700 | [diff] [blame] | 391 | |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 392 | inline T* unsafe_get() const { return m_ptr; } |
| 393 | |
| 394 | // Operators |
Mathias Agopian | ff49de7 | 2011-02-09 18:38:55 -0800 | [diff] [blame] | 395 | |
| 396 | COMPARE_WEAK(==) |
| 397 | COMPARE_WEAK(!=) |
| 398 | COMPARE_WEAK(>) |
| 399 | COMPARE_WEAK(<) |
| 400 | COMPARE_WEAK(<=) |
| 401 | COMPARE_WEAK(>=) |
| 402 | |
| 403 | inline bool operator == (const wp<T>& o) const { |
| 404 | return (m_ptr == o.m_ptr) && (m_refs == o.m_refs); |
| 405 | } |
| 406 | template<typename U> |
| 407 | inline bool operator == (const wp<U>& o) const { |
| 408 | return m_ptr == o.m_ptr; |
| 409 | } |
| 410 | |
| 411 | inline bool operator > (const wp<T>& o) const { |
| 412 | return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr); |
| 413 | } |
| 414 | template<typename U> |
| 415 | inline bool operator > (const wp<U>& o) const { |
| 416 | return (m_ptr == o.m_ptr) ? (m_refs > o.m_refs) : (m_ptr > o.m_ptr); |
| 417 | } |
| 418 | |
| 419 | inline bool operator < (const wp<T>& o) const { |
| 420 | return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr); |
| 421 | } |
| 422 | template<typename U> |
| 423 | inline bool operator < (const wp<U>& o) const { |
| 424 | return (m_ptr == o.m_ptr) ? (m_refs < o.m_refs) : (m_ptr < o.m_ptr); |
| 425 | } |
| 426 | inline bool operator != (const wp<T>& o) const { return m_refs != o.m_refs; } |
| 427 | template<typename U> inline bool operator != (const wp<U>& o) const { return !operator == (o); } |
| 428 | inline bool operator <= (const wp<T>& o) const { return !operator > (o); } |
| 429 | template<typename U> inline bool operator <= (const wp<U>& o) const { return !operator > (o); } |
| 430 | inline bool operator >= (const wp<T>& o) const { return !operator < (o); } |
| 431 | template<typename U> inline bool operator >= (const wp<U>& o) const { return !operator < (o); } |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 432 | |
| 433 | private: |
| 434 | template<typename Y> friend class sp; |
| 435 | template<typename Y> friend class wp; |
| 436 | |
| 437 | T* m_ptr; |
| 438 | weakref_type* m_refs; |
| 439 | }; |
| 440 | |
| 441 | template <typename T> |
| 442 | TextOutput& operator<<(TextOutput& to, const wp<T>& val); |
| 443 | |
Mathias Agopian | ff49de7 | 2011-02-09 18:38:55 -0800 | [diff] [blame] | 444 | #undef COMPARE_WEAK |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 445 | |
| 446 | // --------------------------------------------------------------------------- |
| 447 | // No user serviceable parts below here. |
| 448 | |
| 449 | template<typename T> |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 450 | wp<T>::wp(T* other) |
| 451 | : m_ptr(other) |
| 452 | { |
| 453 | if (other) m_refs = other->createWeak(this); |
| 454 | } |
| 455 | |
| 456 | template<typename T> |
| 457 | wp<T>::wp(const wp<T>& other) |
| 458 | : m_ptr(other.m_ptr), m_refs(other.m_refs) |
| 459 | { |
| 460 | if (m_ptr) m_refs->incWeak(this); |
| 461 | } |
| 462 | |
| 463 | template<typename T> |
| 464 | wp<T>::wp(const sp<T>& other) |
| 465 | : m_ptr(other.m_ptr) |
| 466 | { |
| 467 | if (m_ptr) { |
| 468 | m_refs = m_ptr->createWeak(this); |
| 469 | } |
| 470 | } |
| 471 | |
| 472 | template<typename T> template<typename U> |
| 473 | wp<T>::wp(U* other) |
| 474 | : m_ptr(other) |
| 475 | { |
| 476 | if (other) m_refs = other->createWeak(this); |
| 477 | } |
| 478 | |
| 479 | template<typename T> template<typename U> |
| 480 | wp<T>::wp(const wp<U>& other) |
| 481 | : m_ptr(other.m_ptr) |
| 482 | { |
| 483 | if (m_ptr) { |
| 484 | m_refs = other.m_refs; |
| 485 | m_refs->incWeak(this); |
| 486 | } |
| 487 | } |
| 488 | |
| 489 | template<typename T> template<typename U> |
| 490 | wp<T>::wp(const sp<U>& other) |
| 491 | : m_ptr(other.m_ptr) |
| 492 | { |
| 493 | if (m_ptr) { |
| 494 | m_refs = m_ptr->createWeak(this); |
| 495 | } |
| 496 | } |
| 497 | |
| 498 | template<typename T> |
| 499 | wp<T>::~wp() |
| 500 | { |
| 501 | if (m_ptr) m_refs->decWeak(this); |
| 502 | } |
| 503 | |
| 504 | template<typename T> |
| 505 | wp<T>& wp<T>::operator = (T* other) |
| 506 | { |
| 507 | weakref_type* newRefs = |
Yi Kong | c1a1562 | 2018-07-11 17:37:34 -0700 | [diff] [blame] | 508 | other ? other->createWeak(this) : nullptr; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 509 | if (m_ptr) m_refs->decWeak(this); |
| 510 | m_ptr = other; |
| 511 | m_refs = newRefs; |
| 512 | return *this; |
| 513 | } |
| 514 | |
| 515 | template<typename T> |
| 516 | wp<T>& wp<T>::operator = (const wp<T>& other) |
| 517 | { |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 518 | weakref_type* otherRefs(other.m_refs); |
| 519 | T* otherPtr(other.m_ptr); |
| 520 | if (otherPtr) otherRefs->incWeak(this); |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 521 | if (m_ptr) m_refs->decWeak(this); |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 522 | m_ptr = otherPtr; |
| 523 | m_refs = otherRefs; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 524 | return *this; |
| 525 | } |
| 526 | |
| 527 | template<typename T> |
| 528 | wp<T>& wp<T>::operator = (const sp<T>& other) |
| 529 | { |
| 530 | weakref_type* newRefs = |
Yi Kong | c1a1562 | 2018-07-11 17:37:34 -0700 | [diff] [blame] | 531 | other != nullptr ? other->createWeak(this) : nullptr; |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 532 | T* otherPtr(other.m_ptr); |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 533 | if (m_ptr) m_refs->decWeak(this); |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 534 | m_ptr = otherPtr; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 535 | m_refs = newRefs; |
| 536 | return *this; |
| 537 | } |
| 538 | |
| 539 | template<typename T> template<typename U> |
| 540 | wp<T>& wp<T>::operator = (U* other) |
| 541 | { |
| 542 | weakref_type* newRefs = |
| 543 | other ? other->createWeak(this) : 0; |
| 544 | if (m_ptr) m_refs->decWeak(this); |
| 545 | m_ptr = other; |
| 546 | m_refs = newRefs; |
| 547 | return *this; |
| 548 | } |
| 549 | |
| 550 | template<typename T> template<typename U> |
| 551 | wp<T>& wp<T>::operator = (const wp<U>& other) |
| 552 | { |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 553 | weakref_type* otherRefs(other.m_refs); |
| 554 | U* otherPtr(other.m_ptr); |
| 555 | if (otherPtr) otherRefs->incWeak(this); |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 556 | if (m_ptr) m_refs->decWeak(this); |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 557 | m_ptr = otherPtr; |
| 558 | m_refs = otherRefs; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 559 | return *this; |
| 560 | } |
| 561 | |
| 562 | template<typename T> template<typename U> |
| 563 | wp<T>& wp<T>::operator = (const sp<U>& other) |
| 564 | { |
| 565 | weakref_type* newRefs = |
Yi Kong | e1731a4 | 2018-07-16 18:11:34 -0700 | [diff] [blame] | 566 | other != nullptr ? other->createWeak(this) : 0; |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 567 | U* otherPtr(other.m_ptr); |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 568 | if (m_ptr) m_refs->decWeak(this); |
Mathias Agopian | 7b15167 | 2010-06-24 21:49:02 -0700 | [diff] [blame] | 569 | m_ptr = otherPtr; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 570 | m_refs = newRefs; |
| 571 | return *this; |
| 572 | } |
| 573 | |
| 574 | template<typename T> |
| 575 | void wp<T>::set_object_and_refs(T* other, weakref_type* refs) |
| 576 | { |
| 577 | if (other) refs->incWeak(this); |
| 578 | if (m_ptr) m_refs->decWeak(this); |
| 579 | m_ptr = other; |
| 580 | m_refs = refs; |
| 581 | } |
| 582 | |
| 583 | template<typename T> |
| 584 | sp<T> wp<T>::promote() const |
| 585 | { |
Mathias Agopian | 3e0f875 | 2011-02-24 18:12:34 -0800 | [diff] [blame] | 586 | sp<T> result; |
| 587 | if (m_ptr && m_refs->attemptIncStrong(&result)) { |
| 588 | result.set_pointer(m_ptr); |
| 589 | } |
| 590 | return result; |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 591 | } |
| 592 | |
| 593 | template<typename T> |
| 594 | void wp<T>::clear() |
| 595 | { |
| 596 | if (m_ptr) { |
| 597 | m_refs->decWeak(this); |
| 598 | m_ptr = 0; |
| 599 | } |
| 600 | } |
| 601 | |
| 602 | template <typename T> |
| 603 | inline TextOutput& operator<<(TextOutput& to, const wp<T>& val) |
| 604 | { |
Mathias Agopian | 84a23fa | 2011-02-16 15:23:08 -0800 | [diff] [blame] | 605 | return printWeakPointer(to, val.unsafe_get()); |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 606 | } |
| 607 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 608 | // --------------------------------------------------------------------------- |
| 609 | |
| 610 | // this class just serves as a namespace so TYPE::moveReferences can stay |
| 611 | // private. |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 612 | class ReferenceMover { |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 613 | public: |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 614 | // it would be nice if we could make sure no extra code is generated |
| 615 | // for sp<TYPE> or wp<TYPE> when TYPE is a descendant of RefBase: |
| 616 | // Using a sp<RefBase> override doesn't work; it's a bit like we wanted |
| 617 | // a template<typename TYPE inherits RefBase> template... |
| 618 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 619 | template<typename TYPE> static inline |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 620 | void move_references(sp<TYPE>* dest, sp<TYPE> const* src, size_t n) { |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 621 | |
| 622 | class Renamer : public ReferenceRenamer { |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 623 | sp<TYPE>* d_; |
| 624 | sp<TYPE> const* s_; |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 625 | virtual void operator()(size_t i) const { |
| 626 | // The id are known to be the sp<>'s this pointer |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 627 | TYPE::renameRefId(d_[i].get(), &s_[i], &d_[i]); |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 628 | } |
| 629 | public: |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 630 | Renamer(sp<TYPE>* d, sp<TYPE> const* s) : d_(d), s_(s) { } |
Ukri Niemimuukko | 00e56a2 | 2014-04-29 06:25:28 +0800 | [diff] [blame] | 631 | virtual ~Renamer() { } |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 632 | }; |
| 633 | |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 634 | memmove(dest, src, n*sizeof(sp<TYPE>)); |
| 635 | TYPE::renameRefs(n, Renamer(dest, src)); |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 636 | } |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 637 | |
| 638 | |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 639 | template<typename TYPE> static inline |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 640 | void move_references(wp<TYPE>* dest, wp<TYPE> const* src, size_t n) { |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 641 | |
| 642 | class Renamer : public ReferenceRenamer { |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 643 | wp<TYPE>* d_; |
| 644 | wp<TYPE> const* s_; |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 645 | virtual void operator()(size_t i) const { |
| 646 | // The id are known to be the wp<>'s this pointer |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 647 | TYPE::renameRefId(d_[i].get_refs(), &s_[i], &d_[i]); |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 648 | } |
| 649 | public: |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 650 | Renamer(wp<TYPE>* rd, wp<TYPE> const* rs) : d_(rd), s_(rs) { } |
Ukri Niemimuukko | 00e56a2 | 2014-04-29 06:25:28 +0800 | [diff] [blame] | 651 | virtual ~Renamer() { } |
Mathias Agopian | 6cd548c | 2013-03-18 22:27:41 -0700 | [diff] [blame] | 652 | }; |
| 653 | |
Colin Cross | 17b5b82 | 2016-09-15 18:15:37 -0700 | [diff] [blame] | 654 | memmove(dest, src, n*sizeof(wp<TYPE>)); |
| 655 | TYPE::renameRefs(n, Renamer(dest, src)); |
Mathias Agopian | b26ea8b | 2011-02-16 20:23:43 -0800 | [diff] [blame] | 656 | } |
| 657 | }; |
| 658 | |
| 659 | // specialization for moving sp<> and wp<> types. |
| 660 | // these are used by the [Sorted|Keyed]Vector<> implementations |
| 661 | // sp<> and wp<> need to be handled specially, because they do not |
| 662 | // have trivial copy operation in the general case (see RefBase.cpp |
| 663 | // when DEBUG ops are enabled), but can be implemented very |
| 664 | // efficiently in most cases. |
| 665 | |
| 666 | template<typename TYPE> inline |
| 667 | void move_forward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { |
| 668 | ReferenceMover::move_references(d, s, n); |
| 669 | } |
| 670 | |
| 671 | template<typename TYPE> inline |
| 672 | void move_backward_type(sp<TYPE>* d, sp<TYPE> const* s, size_t n) { |
| 673 | ReferenceMover::move_references(d, s, n); |
| 674 | } |
| 675 | |
| 676 | template<typename TYPE> inline |
| 677 | void move_forward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { |
| 678 | ReferenceMover::move_references(d, s, n); |
| 679 | } |
| 680 | |
| 681 | template<typename TYPE> inline |
| 682 | void move_backward_type(wp<TYPE>* d, wp<TYPE> const* s, size_t n) { |
| 683 | ReferenceMover::move_references(d, s, n); |
| 684 | } |
| 685 | |
Pirama Arumuga Nainar | eab48ce | 2018-04-10 14:31:29 -0700 | [diff] [blame] | 686 | } // namespace android |
The Android Open Source Project | cbb1011 | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 687 | |
| 688 | // --------------------------------------------------------------------------- |
| 689 | |
| 690 | #endif // ANDROID_REF_BASE_H |