1// Copyright (c) 2012 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#include "net/disk_cache/mapped_file.h"
6
7#include <errno.h>
8#include <sys/mman.h>
9
10#include "base/files/file_path.h"
11#include "base/logging.h"
12#include "net/disk_cache/disk_cache.h"
13
14namespace disk_cache {
15
16void* MappedFile::Init(const base::FilePath& name, size_t size) {
17  DCHECK(!init_);
18  if (init_ || !File::Init(name))
19    return NULL;
20
21  size_t temp_len = size ? size : 4096;
22  if (!size)
23    size = GetLength();
24
25  buffer_ = mmap(NULL, size, PROT_READ | PROT_WRITE, MAP_SHARED,
26                 platform_file(), 0);
27  init_ = true;
28  view_size_ = size;
29  DCHECK(reinterpret_cast<intptr_t>(buffer_) != -1);
30  if (reinterpret_cast<intptr_t>(buffer_) == -1)
31    buffer_ = 0;
32
33  // Make sure we detect hardware failures reading the headers.
34  scoped_ptr<char[]> temp(new char[temp_len]);
35  if (!Read(temp.get(), temp_len, 0))
36    return NULL;
37
38  return buffer_;
39}
40
41bool MappedFile::Load(const FileBlock* block) {
42  size_t offset = block->offset() + view_size_;
43  return Read(block->buffer(), block->size(), offset);
44}
45
46bool MappedFile::Store(const FileBlock* block) {
47  size_t offset = block->offset() + view_size_;
48  return Write(block->buffer(), block->size(), offset);
49}
50
51void MappedFile::Flush() {
52}
53
54MappedFile::~MappedFile() {
55  if (!init_)
56    return;
57
58  if (buffer_) {
59    int ret = munmap(buffer_, view_size_);
60    DCHECK_EQ(0, ret);
61  }
62}
63
64}  // namespace disk_cache
65