1// Copyright (c) 2010 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// See net/disk_cache/disk_cache.h for the public interface of the cache.
6
7#ifndef NET_DISK_CACHE_MAPPED_FILE_H_
8#define NET_DISK_CACHE_MAPPED_FILE_H_
9#pragma once
10
11#include "net/disk_cache/disk_format.h"
12#include "net/disk_cache/file.h"
13#include "net/disk_cache/file_block.h"
14
15class FilePath;
16
17namespace disk_cache {
18
19// This class implements a memory mapped file used to access block-files. The
20// idea is that the header and bitmap will be memory mapped all the time, and
21// the actual data for the blocks will be access asynchronously (most of the
22// time).
23class MappedFile : public File {
24 public:
25  MappedFile() : File(true), init_(false) {}
26
27  // Performs object initialization. name is the file to use, and size is the
28  // ammount of data to memory map from th efile. If size is 0, the whole file
29  // will be mapped in memory.
30  void* Init(const FilePath& name, size_t size);
31
32  void* buffer() const {
33    return buffer_;
34  }
35
36  // Loads or stores a given block from the backing file (synchronously).
37  bool Load(const FileBlock* block);
38  bool Store(const FileBlock* block);
39
40 private:
41  virtual ~MappedFile();
42
43  bool init_;
44#if defined(OS_WIN)
45  HANDLE section_;
46#endif
47  void* buffer_;  // Address of the memory mapped buffer.
48  size_t view_size_;  // Size of the memory pointed by buffer_.
49
50  DISALLOW_COPY_AND_ASSIGN(MappedFile);
51};
52
53}  // namespace disk_cache
54
55#endif  // NET_DISK_CACHE_MAPPED_FILE_H_
56