mapped_file.h

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/*
 * Copyright (C) 2018 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.
 */
 
#pragma once
 
#include <sys/types.h>
 
#include <memory>
 
#include "android-base/macros.h"
#include "android-base/off64_t.h"
#include "android-base/unique_fd.h"
 
#if defined(_WIN32)
#include <windows.h>
#define PROT_READ 1
#define PROT_WRITE 2
using os_handle = HANDLE;
#else
#include <sys/mman.h>
using os_handle = int;
#endif
 
namespace android {
namespace base {
 
class MappedFile {
 public:
  static std::unique_ptr<MappedFile> FromFd(borrowed_fd fd, off64_t offset, size_t length,
                                            int prot);
 
  static std::unique_ptr<MappedFile> FromOsHandle(os_handle h, off64_t offset, size_t length,
                                                  int prot);
 
  ~MappedFile();
 
  MappedFile(MappedFile&& other);
  MappedFile& operator=(MappedFile&& other);
 
  char* data() const { return base_ + offset_; }
  size_t size() const { return size_; }
 
 private:
  DISALLOW_IMPLICIT_CONSTRUCTORS(MappedFile);
 
  void Close();
 
  char* base_;
  size_t size_;
 
  size_t offset_;
 
#if defined(_WIN32)
  MappedFile(char* base, size_t size, size_t offset, HANDLE handle)
      : base_(base), size_(size), offset_(offset), handle_(handle) {}
  HANDLE handle_;
#else
  MappedFile(char* base, size_t size, size_t offset) : base_(base), size_(size), offset_(offset) {}
#endif
};
 
}  // namespace base
}  // namespace android