1 // Copyright 2012 The Chromium Authors
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/blockfile/mapped_file.h"
6
7 #include <stdlib.h>
8
9 #include "base/check.h"
10 #include "base/files/file_path.h"
11
12 namespace disk_cache {
13
Init(const base::FilePath & name,size_t size)14 void* MappedFile::Init(const base::FilePath& name, size_t size) {
15 DCHECK(!init_);
16 if (init_ || !File::Init(name))
17 return nullptr;
18
19 if (!size)
20 size = GetLength();
21
22 buffer_ = malloc(size);
23 snapshot_ = malloc(size);
24 if (buffer_ && snapshot_ && Read(buffer_, size, 0)) {
25 memcpy(snapshot_, buffer_, size);
26 } else {
27 free(buffer_);
28 free(snapshot_);
29 buffer_ = nullptr;
30 snapshot_ = nullptr;
31 }
32
33 init_ = true;
34 view_size_ = size;
35 return buffer_;
36 }
37
Flush()38 void MappedFile::Flush() {
39 DCHECK(buffer_);
40 DCHECK(snapshot_);
41 const char* buffer_ptr = static_cast<const char*>(buffer_);
42 char* snapshot_ptr = static_cast<char*>(snapshot_);
43 const size_t block_size = 4096;
44 for (size_t offset = 0; offset < view_size_; offset += block_size) {
45 size_t size = std::min(view_size_ - offset, block_size);
46 if (memcmp(snapshot_ptr + offset, buffer_ptr + offset, size)) {
47 memcpy(snapshot_ptr + offset, buffer_ptr + offset, size);
48 Write(snapshot_ptr + offset, size, offset);
49 }
50 }
51 }
52
~MappedFile()53 MappedFile::~MappedFile() {
54 if (!init_)
55 return;
56
57 if (buffer_ && snapshot_) {
58 Flush();
59 }
60 free(buffer_);
61 free(snapshot_);
62 }
63
64 } // namespace disk_cache
65