net/disk_cache/simple/simple_entry_format.h

   1 // Copyright (c) 2013 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 #ifndef NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_
   6 #define NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_
   7
   8 #include <stdint.h>
   9
  10 #include "base/basictypes.h"
  11 #include "net/base/net_export.h"
  12
  13 namespace base {
  14 class Time;
  15 }
  16
  17 namespace disk_cache {
  18
  19 const uint64 kSimpleInitialMagicNumber = UINT64_C(0xfcfb6d1ba7725c30);
  20 const uint64 kSimpleFinalMagicNumber = UINT64_C(0xf4fa6f45970d41d8);
  21 const uint64 kSimpleSparseRangeMagicNumber = UINT64_C(0xeb97bf016553676b);
  22
  23 // A file containing stream 0 and stream 1 in the Simple cache consists of:
  24 //   - a SimpleFileHeader.
  25 //   - the key.
  26 //   - the data from stream 1.
  27 //   - a SimpleFileEOF record for stream 1.
  28 //   - the data from stream 0.
  29 //   - a SimpleFileEOF record for stream 0.
  30
  31 // A file containing stream 2 in the Simple cache consists of:
  32 //   - a SimpleFileHeader.
  33 //   - the key.
  34 //   - the data.
  35 //   - at the end, a SimpleFileEOF record.
  36 static const int kSimpleEntryFileCount = 2;
  37 static const int kSimpleEntryStreamCount = 3;
  38
  39 struct NET_EXPORT_PRIVATE SimpleFileHeader {
  40   SimpleFileHeader();
  41
  42   uint64 initial_magic_number;
  43   uint32 version;
  44   uint32 key_length;
  45   uint32 key_hash;
  46 };
  47
  48 struct NET_EXPORT_PRIVATE SimpleFileEOF {
  49   enum Flags {
  50     FLAG_HAS_CRC32 = (1U << 0),
  51   };
  52
  53   SimpleFileEOF();
  54
  55   uint64 final_magic_number;
  56   uint32 flags;
  57   uint32 data_crc32;
  58   // |stream_size| is only used in the EOF record for stream 0.
  59   uint32 stream_size;
  60 };
  61
  62 struct SimpleFileSparseRangeHeader {
  63   SimpleFileSparseRangeHeader();
  64
  65   uint64 sparse_range_magic_number;
  66   int64 offset;
  67   int64 length;
  68   uint32 data_crc32;
  69 };
  70
  71 }  // namespace disk_cache
  72
  73 #endif  // NET_DISK_CACHE_SIMPLE_SIMPLE_ENTRY_FORMAT_H_