/*

 * Copyright (c) 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#ifndef OS_BSD_GC_Z_ZBACKINGFILE_BSD_HPP

#define OS_BSD_GC_Z_ZBACKINGFILE_BSD_HPP

#include "memory/allocation.hpp"

class ZPhysicalMemory;

// On macOS, we use a virtual backing file. It is represented by a reserved virtual

// address space, in which we commit physical memory using the mach_vm_map() API.

// The multi-mapping API simply remaps these addresses using mach_vm_remap() into

// the different heap views. This works as-if there was a backing file, it's just

// that the file is represented with memory mappings instead.

class ZBackingFile {

private:

  uintptr_t _base;

  size_t    _size;

  bool      _initialized;

  bool commit_inner(size_t offset, size_t length);

public:

  ZBackingFile();

  bool is_initialized() const;

  size_t size() const;

  size_t commit(size_t offset, size_t length);

  size_t uncommit(size_t offset, size_t length);

  void map(uintptr_t addr, size_t size, uintptr_t offset) const;

  void unmap(uintptr_t addr, size_t size) const;

};

#endif // OS_BSD_GC_Z_ZBACKINGFILE_BSD_HPP