legacy: move hardlink helpers, NSIndex1, AES, and PBKDF2 key file methods to borg.legacy, refs #9556

[mr-raj12]

Description

Moves four borg 1.x components into borg.legacy, refs #9556.

• helpers/fs.py → legacy/helpers.py: hardlink helper functions
• hashindex.pyx → legacy/hashindex.py: NSIndex1 (borg 1.x hash index format)
• crypto/low_level.pyx → legacy/crypto/low_level.pyx: cdef class AES (AES-256-CTR for borg 1.x key file encryption)
• crypto/key.py → legacy/crypto/key.py: PBKDF2 key file methods extracted into Pbkdf2FileMixin

AES needs its own .pyx , cdef types can't live in a .py file and can't be shared across binary extensions. ro_buffer (a cdef helper) is duplicated rather than imported.

setup.py and pyproject.toml updated to build and type-check borg.legacy.crypto.low_level. All consumer imports updated. No logic changes.

Refs #9556

Checklist

• PR is against master
• New code has tests
• Tests pass
• Commit message references related issue

[codecov]

Codecov Report

❌ Patch coverage is 80.00000% with 28 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.78%. Comparing base (b0f3096) to head (228ac45).
⚠️ Report is 22 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
src/borg/legacy/hashindex.py	83.52%	7 Missing and 7 partials ⚠️
src/borg/legacy/crypto/key.py	68.29%	10 Missing and 3 partials ⚠️
src/borg/crypto/key.py	66.66%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #9664      +/-   ##
==========================================
+ Coverage   83.00%   83.78%   +0.77%     
==========================================
  Files          90       92       +2     
  Lines       15549    15653     +104     
  Branches     2340     2356      +16     
==========================================
+ Hits        12907    13115     +208     
+ Misses       1887     1796      -91     
+ Partials      755      742      -13     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[ThomasWaldmann]

Somehow the tests didn't pass in CI.

[mr-raj12]

Somehow the tests didn't pass in CI.

Fixing

[ThomasWaldmann]

LGTM.

About the kdf benchmarking: thinking about it, guess we should just not do that.

kdfs are supposed to be slow, so not much point in benchmarking them.

IIRC the benchmark outputs even a note about that.

[mr-raj12]

LGTM.

About the kdf benchmarking: thinking about it, guess we should just not do that.

kdfs are supposed to be slow, so not much point in benchmarking them.

IIRC the benchmark outputs even a note about that.

Should I remove the KDF section here or handle it in a follow-up PR?

[ThomasWaldmann]

whatever works better for you.

[ThomasWaldmann]

pbkdf2 stays in FlexiKey since benchmark_cmd.py calls it directly.

Not anymore. :)

[ThomasWaldmann]

@mr-raj12 are you working on moving the pbkdf2 related code?

[mr-raj12]

@mr-raj12 are you working on moving the pbkdf2 related code?

Yes, will raise a PR for shortly

[ThomasWaldmann]

If you don't want to put it into this PR, shall we merge this first?

[mr-raj12]

If you don't want to put it into this PR, shall we merge this first?

Yaa, I'm working on it on a seperate branch