chrome/utility/safe_browsing/mac/hfs.h

   1 // Copyright 2015 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 CHROME_UTILITY_SAFE_BROWSING_MAC_HFS_H_
   6 #define CHROME_UTILITY_SAFE_BROWSING_MAC_HFS_H_
   7
   8 #include <hfs/hfs_format.h>
   9 #include <stdint.h>
  10
  11 #include "base/macros.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/strings/string16.h"
  14
  15 namespace safe_browsing {
  16 namespace dmg {
  17
  18 class ReadStream;
  19 class HFSBTreeIterator;
  20 class HFSForkReadStream;
  21
  22 // HFSIterator is a read-only iterator over an HFS+ file system. It provides
  23 // access to the data fork of all files on the system, as well as the path. This
  24 // implementation has several deliberate limitations:
  25 //   - Only HFS+ and HFSX are supported.
  26 //   - The journal file is ignored. As this is intended to be used for HFS+ in
  27 //     a DMG, replaying the journal should not typically be required.
  28 //   - The extents overflow file is not consulted. In a DMG, the file system
  29 //     should not be fragmented, and so consulting this should not typically be
  30 //     required.
  31 //   - No access is provided to resource forks.
  32 //   - Getting the ReadStream for hard linked files is not supported.
  33 //   - Files in hard linked directories are ignored.
  34 //   - No content will be returned for files that are decmpfs compressed.
  35 // For information on the HFS format, see
  36 // <https://developer.apple.com/legacy/library/technotes/tn/tn1150.html>.
  37 class HFSIterator {
  38  public:
  39   // Constructs an iterator from a stream.
  40   explicit HFSIterator(ReadStream* stream);
  41   ~HFSIterator();
  42
  43   // Opens the filesystem and initializes the iterator. The iterator is
  44   // initialized to an invalid item before the first entry. Use Next() to
  45   // advance the iterator. This method must be called before any other
  46   // method. If this returns false, it is not legal to call any other methods.
  47   bool Open();
  48
  49   // Advances the iterator to the next item. If this returns false, then it
  50   // is not legal to call any other methods.
  51   bool Next();
  52
  53   // Returns true if the current iterator item is a directory and false if it
  54   // is a file.
  55   bool IsDirectory();
  56
  57   // Returns true if the current iterator item is a symbolic link.
  58   bool IsSymbolicLink();
  59
  60   // Returns true if the current iterator item is a hard link.
  61   bool IsHardLink();
  62
  63   // Returns true if the current iterator item is decmpfs-compressed.
  64   bool IsDecmpfsCompressed();
  65
  66   // Returns the full filesystem path of the current iterator item.
  67   base::string16 GetPath();
  68
  69   // Returns a stream for the data fork of the current iterator item. This may
  70   // only be called if IsDirectory() and IsHardLink() returns false.
  71   scoped_ptr<ReadStream> GetReadStream();
  72
  73  private:
  74   friend class HFSForkReadStream;
  75
  76   // Moves the |stream_| position to a specific HFS+ |block|.
  77   bool SeekToBlock(uint64_t block);
  78
  79   // Reads the catalog file to initialize the iterator.
  80   bool ReadCatalogFile();
  81
  82   uint32_t block_size() const { return volume_header_.blockSize; }
  83   ReadStream* stream() const { return stream_; }
  84
  85   ReadStream* const stream_;  // The stream backing the filesystem.
  86   HFSPlusVolumeHeader volume_header_;
  87   scoped_ptr<HFSForkReadStream> catalog_file_;  // Data of the catalog file.
  88   scoped_ptr<HFSBTreeIterator> catalog_;  // Iterator over the catalog file.
  89
  90   DISALLOW_COPY_AND_ASSIGN(HFSIterator);
  91 };
  92
  93 }  // namespace dmg
  94 }  // namespace safe_browsing
  95
  96 #endif  // CHROME_UTILITY_SAFE_BROWSING_MAC_HFS_H_