1 // Copyright 2021 The Dawn Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #ifndef UTILS_SCOPEDAUTORELEASEPOOL_H_ 16 #define UTILS_SCOPEDAUTORELEASEPOOL_H_ 17 18 #include "common/Compiler.h" 19 20 #include <cstddef> 21 22 namespace utils { 23 24 /** 25 * ScopedAutoreleasePool is a scoped class which initializes an NSAutoreleasePool on 26 * creation, and drains it on destruction. On non-Apple platforms, ScopedAutoreleasePool 27 * is a no-op. 28 * 29 * An autoreleasepool is needed when using protocol objects in Objective-C because Cocoa 30 * expects a pool to always be available in each thread. If a pool is not available, then 31 * autoreleased objects will never be released and will leak. 32 * 33 * In long-running blocks of code or loops, it is important to periodically create and drain 34 * autorelease pools so that memory is recycled. In Dawn's tests, we have an autoreleasepool 35 * per-test. In graphics applications it's advised to create an autoreleasepool around the 36 * frame loop. Ex.) 37 * void frame() { 38 * // Any protocol objects will be reclaimed when this object falls out of scope. 39 * utils::ScopedAutoreleasePool pool; 40 * 41 * // do rendering ... 42 * } 43 */ 44 class DAWN_NO_DISCARD ScopedAutoreleasePool { 45 public: 46 ScopedAutoreleasePool(); 47 ~ScopedAutoreleasePool(); 48 49 ScopedAutoreleasePool(const ScopedAutoreleasePool&) = delete; 50 ScopedAutoreleasePool& operator=(const ScopedAutoreleasePool&) = delete; 51 52 ScopedAutoreleasePool(ScopedAutoreleasePool&&); 53 ScopedAutoreleasePool& operator=(ScopedAutoreleasePool&&); 54 55 private: 56 void* mPool = nullptr; 57 }; 58 59 } // namespace utils 60 61 #endif // UTILS_SCOPEDAUTORELEASEPOOL_H_ 62