memory_mapped_file.h 2.1 KB
Newer Older
gejun's avatar
gejun committed
1 2 3 4
// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

5 6
#ifndef BUTIL_FILES_MEMORY_MAPPED_FILE_H_
#define BUTIL_FILES_MEMORY_MAPPED_FILE_H_
gejun's avatar
gejun committed
7

8 9 10 11
#include "butil/base_export.h"
#include "butil/basictypes.h"
#include "butil/files/file.h"
#include "butil/build_config.h"
gejun's avatar
gejun committed
12 13 14 15 16

#if defined(OS_WIN)
#include <windows.h>
#endif

17
namespace butil {
gejun's avatar
gejun committed
18 19 20

class FilePath;

21
class BUTIL_EXPORT MemoryMappedFile {
gejun's avatar
gejun committed
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69
 public:
  // The default constructor sets all members to invalid/null values.
  MemoryMappedFile();
  ~MemoryMappedFile();

  // Opens an existing file and maps it into memory. Access is restricted to
  // read only. If this object already points to a valid memory mapped file
  // then this method will fail and return false. If it cannot open the file,
  // the file does not exist, or the memory mapping fails, it will return false.
  // Later we may want to allow the user to specify access.
  bool Initialize(const FilePath& file_name);

  // As above, but works with an already-opened file. MemoryMappedFile takes
  // ownership of |file| and closes it when done.
  bool Initialize(File file);

#if defined(OS_WIN)
  // Opens an existing file and maps it as an image section. Please refer to
  // the Initialize function above for additional information.
  bool InitializeAsImageSection(const FilePath& file_name);
#endif  // OS_WIN

  const uint8_t* data() const { return data_; }
  size_t length() const { return length_; }

  // Is file_ a valid file handle that points to an open, memory mapped file?
  bool IsValid() const;

 private:
  // Map the file to memory, set data_ to that memory address. Return true on
  // success, false on any kind of failure. This is a helper for Initialize().
  bool MapFileToMemory();

  // Closes all open handles.
  void CloseHandles();

  File file_;
  uint8_t* data_;
  size_t length_;

#if defined(OS_WIN)
  win::ScopedHandle file_mapping_;
  bool image_;  // Map as an image.
#endif

  DISALLOW_COPY_AND_ASSIGN(MemoryMappedFile);
};

70
}  // namespace butil
gejun's avatar
gejun committed
71

72
#endif  // BUTIL_FILES_MEMORY_MAPPED_FILE_H_