// Copyright 2018 The Abseil Authors. // // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // https://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. #ifndef ABSL_BASE_INTERNAL_HIDE_PTR_H_ #define ABSL_BASE_INTERNAL_HIDE_PTR_H_ #include <cstdint> #include "absl/base/config.h" namespace absl { ABSL_NAMESPACE_BEGIN namespace base_internal { // Arbitrary value with high bits set. Xor'ing with it is unlikely // to map one valid pointer to another valid pointer. constexpr uintptr_t HideMask() { return (uintptr_t{0xF03A5F7BU} << (sizeof(uintptr_t) - 4) * 8) | 0xF03A5F7BU; } // Hide a pointer from the leak checker. For internal use only. // Differs from absl::IgnoreLeak(ptr) in that absl::IgnoreLeak(ptr) causes ptr // and all objects reachable from ptr to be ignored by the leak checker. template <class T> inline uintptr_t HidePtr(T* ptr) { return reinterpret_cast<uintptr_t>(ptr) ^ HideMask(); } // Return a pointer that has been hidden from the leak checker. // For internal use only. template <class T> inline T* UnhidePtr(uintptr_t hidden) { return reinterpret_cast<T*>(hidden ^ HideMask()); } } // namespace base_internal ABSL_NAMESPACE_END } // namespace absl #endif // ABSL_BASE_INTERNAL_HIDE_PTR_H_