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/*
* Copyright (C) 2019 The Android Open Source Project
*
* 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
*
* http://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 SRC_PROFILING_MEMORY_UNHOOKED_ALLOCATOR_H_
#define SRC_PROFILING_MEMORY_UNHOOKED_ALLOCATOR_H_
#include <stdlib.h>
#include <atomic>
#include <exception>
namespace perfetto {
namespace profiling {
// An allocator that uses the given |malloc| & |free| function pointers to
// allocate/deallocate memory. Used in the heapprofd_client library, which hooks
// the malloc functions in a target process, and therefore needs to use this
// allocator to not have its own heap usage enter the hooks.
//
// See https://en.cppreference.com/w/cpp/named_req/Allocator.
template <typename T>
class UnhookedAllocator {
public:
template <typename U>
friend class UnhookedAllocator;
// to satisfy the Allocator interface
using value_type = T;
// for implementation convenience
using unhooked_malloc_t = void* (*)(size_t);
using unhooked_free_t = void (*)(void*);
UnhookedAllocator(unhooked_malloc_t unhooked_malloc,
unhooked_free_t unhooked_free)
: unhooked_malloc_(unhooked_malloc), unhooked_free_(unhooked_free) {}
template <typename U>
constexpr UnhookedAllocator(const UnhookedAllocator<U>& other) noexcept
: unhooked_malloc_(other.unhooked_malloc_),
unhooked_free_(other.unhooked_free_) {}
T* allocate(size_t n) {
if (n > size_t(-1) / sizeof(T))
std::terminate();
if (T* p = static_cast<T*>(unhooked_malloc_(n * sizeof(T))))
return p;
std::terminate();
}
void deallocate(T* p, size_t) noexcept { unhooked_free_(p); }
private:
unhooked_malloc_t unhooked_malloc_ = nullptr;
unhooked_free_t unhooked_free_ = nullptr;
};
template <typename T, typename U>
bool operator==(const UnhookedAllocator<T>& first,
const UnhookedAllocator<U>& second) {
return first.unhooked_malloc_ == second.unhooked_malloc_ &&
first.unhooked_free_ == second.unhooked_free_;
}
template <typename T, typename U>
bool operator!=(const UnhookedAllocator<T>& first,
const UnhookedAllocator<U>& second) {
return !(first == second);
}
} // namespace profiling
} // namespace perfetto
#endif // SRC_PROFILING_MEMORY_UNHOOKED_ALLOCATOR_H_