NixOS/nix

Collect "file system object" parts of `libnixutil` together

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#9,278 opened on Nov 2, 2023

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good first issueidea approved

Description

We now have bunch of involved code for working with file system objects.

Someday it might be good to codify this into a new libnixfile. (Don't worry, that doesn't mean I am planning a "file-only" Nix!) But going down that road would mean lots of little libraries, which could have implications for dynamic linking. For now we can instead group files into subdirectories (see build/ in libstore for this same concept), but keep all such directories linked together in the parent library.

For initial contents I am thinking:

  • src/libutil/archive
  • src/libutil/canon-path
  • src/libutil/fs-sink
  • src/libutil/git.cc will contain more stuff after #8918
  • src/libutil/posix-source-accessor
  • src/libutil/source-accessor
  • src/libutil/file-content-address New, doesn't distinguish between "flat" and "text" because w.r.t file system objects (as opposed to store objects) they are the same.

I think this will continue growing too based on our current plans. libnixfetchers only barely depends on the store layer anyways, so I think some or even all of it could end up here too.

Contributor guide

Tech stack
cpp
Domain
developer experiencetooling
Issue type
refactor
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
basic C++ knowledgeunderstanding of Nix codebase structure
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
The issue proposes grouping file system object related code in libutil into subdirectories. First, explore the current files listed: src/libutil/archive, src/libutil/canon path, src/libutil/fs sink, src/libutil/git.cc, src/libutil/posix source accessor, src/libutil/source accessor, and consider where to place new code like file content address. Review existing subdirectory patterns in libstore (e.g., build/). Then create a plan to move and organize these files, ensuring includes and build system (Makefile or CMake) are updated accordingly. Check for dependencies between these components to ensure no breakage.
Collect "file system object" parts of `libnixutil` together · NixOS/nix#9278 | Good First Issue