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base / allocator / partition_allocator / src / partition_alloc / internal_allocator_forward.h [blame]
// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef PARTITION_ALLOC_INTERNAL_ALLOCATOR_FORWARD_H_
#define PARTITION_ALLOC_INTERNAL_ALLOCATOR_FORWARD_H_
#include <new>
#include <type_traits>
#include "partition_alloc/partition_alloc_base/component_export.h"
#include "partition_alloc/partition_alloc_forward.h"
// Internal Allocator can be used to get heap allocations required to
// implement PartitionAlloc's feature.
// As Internal Allocator being PartitionAlloc with minimal configuration,
// it is not allowed to use this allocator for PA's core implementation to avoid
// reentrancy issues. Also don't use this when satisfying the very first PA-E
// allocation of the process.
namespace partition_alloc::internal {
PA_COMPONENT_EXPORT(PARTITION_ALLOC)
PartitionRoot& InternalAllocatorRoot();
// A class that meets C++ named requirements, Allocator.
template <typename T>
class InternalAllocator {
public:
using value_type = T;
using is_always_equal = std::true_type;
InternalAllocator() = default;
template <typename U>
InternalAllocator(const InternalAllocator<U>&) {} // NOLINT
template <typename U>
InternalAllocator& operator=(const InternalAllocator<U>&) {
return *this;
}
template <typename U>
bool operator==(const InternalAllocator<U>&) {
// InternalAllocator<T> can free allocations made by InternalAllocator<U>.
return true;
}
value_type* allocate(std::size_t count);
void deallocate(value_type* ptr, std::size_t);
};
// Inherit this to make a class allocated on the internal partition.
struct PA_COMPONENT_EXPORT(PARTITION_ALLOC) InternalPartitionAllocated {
static void* operator new(size_t count);
static void* operator new(size_t count, std::align_val_t alignment);
// Though we do not forward placement new, we need to define this explicitly
// to allow it.
static void* operator new(std::size_t, void* ptr) { return ptr; }
static void operator delete(void* ptr);
static void operator delete(void* ptr, std::align_val_t);
};
// Create an object on heap in the internal partition.
template <typename T, typename... Args>
T* ConstructAtInternalPartition(Args&&... args);
// Destroy an object on heap in the internal partition.
// TODO(crbug.com/40274826) This is an unused function. Start using it in tests
// and/or in production code.
template <typename T>
void DestroyAtInternalPartition(T* ptr);
// A deleter for `std::unique_ptr<T>`.
struct PA_COMPONENT_EXPORT(PARTITION_ALLOC) InternalPartitionDeleter final {
void operator()(void* ptr) const;
};
} // namespace partition_alloc::internal
#endif // PARTITION_ALLOC_INTERNAL_ALLOCATOR_FORWARD_H_