Add new DirEntry class

[Schamper]

Related to #649, but I don't want to close that with this PR since there's still quite a lot of work left to do.

This is my initial effort into adding a DirEntry class that accompanies FilesystemEntry. With this, a FilesystemEntry could be seen more akin to an "inode", and DirEntry is, obviously, a "dirent". The function signature of .scandir() changes with this PR.

Not all possible improvements are immediately implemented with this PR, I want to do that incrementally. For example, VirtualFilesystem should get a major refactor, which means a ton of other "filesystems" will too. There's also a ton of separate improvements to be made for each filesystem, as most implementations don't currently have a DirEntry concept of their own (with the exception of VMFS and APFS, and NTFS with fox-it/dissect.ntfs#48, which this PR depends on).

Also the mentioned possibility of "flags" on directory entries in #649 is not implemented yet (e.g. "deleted").

[codecov]

Codecov Report

❌ Patch coverage is 72.96037% with 116 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.02%. Comparing base (73dd16d) to head (786bccd).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
dissect/target/filesystems/ntfs.py	44.89%	27 Missing ⚠️
dissect/target/filesystems/vmfs.py	48.00%	13 Missing ⚠️
dissect/target/filesystems/btrfs.py	50.00%	8 Missing ⚠️
dissect/target/filesystem.py	91.25%	7 Missing ⚠️
dissect/target/filesystems/extfs.py	60.00%	6 Missing ⚠️
dissect/target/filesystems/ffs.py	60.00%	6 Missing ⚠️
dissect/target/filesystems/smb.py	68.42%	6 Missing ⚠️
dissect/target/filesystems/xfs.py	60.00%	6 Missing ⚠️
dissect/target/filesystems/fat.py	61.53%	5 Missing ⚠️
dissect/target/filesystems/ad1.py	60.00%	4 Missing ⚠️
... and 9 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1389      +/-   ##
==========================================
+ Coverage   80.94%   81.02%   +0.08%     
==========================================
  Files         376      376              
  Lines       33544    33593      +49     
==========================================
+ Hits        27153    27220      +67     
+ Misses       6391     6373      -18     

Flag	Coverage Δ
unittests	81.02% <72.96%> (+0.08%)	⬆️

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[codspeed-hq]

CodSpeed Performance Report

Merging #1389 will not alter performance

_{Comparing direntry (786bccd) with main (73dd16d)}

Summary

✅ 9 untouched

[twiggler]

Don't forget about APFS

[twiggler]

I think the windows unit tests are failing

[Schamper]

Don't forget about APFS

If this is merged before #1365, I'll do it in that PR. If #1365 is merged before this, I'll fix it here.

[JSCU-CNI]

Am I correct to assume this PR should or does not introduce breaking changes for existing filesystem implementations? I see the TargetPath.get method does some duck typing for the _direntry attribute.

[Schamper]

Am I correct to assume this PR should or does not introduce breaking changes for existing filesystem implementations? I see the TargetPath.get method does some duck typing for the _direntry attribute.

If you implemented your own Filesystem, then there are some necessary changes:

• FilesystemEntry.scandir() -> should yield DirEntry now
• FilesystemEntry.iterdir() -> can be removed entirely
• Ideally, you also implement your own subclass of DirEntry, otherwise you get a very inefficient fallback

Any code that uses the scandir method directly will need to be adjusted to deal with DirEntry. However, all code that uses TargetPath does not require any changes. This will also be reflected in the changelog in the release that contains this change.