system/ulib/fbl/include/fbl/alloc_checker.h

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#pragma once

#include <new>
#include <stddef.h>

namespace fbl {

// An object which is passed to operator new to allow client code to handle
// allocation failures.  Once armed by operator new, the client must call `check()`
// to verify the state of the allocation checker before it goes out of scope.
//
// Use it like this:
//
//     AllocChecker ac;
//     MyObject* obj = new (&ac) MyObject();
//     if (!ac.check()) {
//         // handle allocation failure (obj will be null)
//     }
class AllocChecker {
public:
    AllocChecker();
    ~AllocChecker();
    void arm(size_t size, bool result);
    bool check();

private:
    unsigned state_;
};

} // namespace fbl
void* operator new(size_t size, std::align_val_t align, fbl::AllocChecker* ac) noexcept;
void* operator new[](size_t size, std::align_val_t align, fbl::AllocChecker* ac) noexcept;

void* operator new(size_t size, fbl::AllocChecker* ac) noexcept;
void* operator new[](size_t size, fbl::AllocChecker* ac) noexcept;