39 lines
1.7 KiB
Markdown
39 lines
1.7 KiB
Markdown
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title = "Rust's Impure Path"
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date = 2022-10-30T12:47:41-05:00
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languages = ["rust"]
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tags = ["rust"]
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+++
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I work on [garbage], a project that touches the filesystem a lot. Because of
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this, I'd really like to control when and where these filesystem accesses
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happen.
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[garbage]: https://git.sr.ht/~mzhang/garbage
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The Rust standard library has a `fs` module, which I expect to _exclusively_
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contain filesystem access primitives. But actually a lot of the functionality
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also gets leaked into `std::path::Path`.
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In my ideal world, `Path` only deals with the data in a path, not its
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interaction with the filesystem. So it should never be able to check whether or
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not a path [exists], for example, or if a path [is a symlink][is_symlink]. Those
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should be delegated to something within `fs`.
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[exists]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.exists
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[is_symlink]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.is_symlink
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In addition, many of these functions automatically resolve symlinks, without
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built-in ways of achieving the same functionality without resolving symlinks, so
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I ended up having to fill those in myself. For example, I really just expect
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[`canonicalize`] to be an in-memory manipulation of path components.
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[`canonicalize`]: https://doc.rust-lang.org/stable/std/path/struct.Path.html#method.canonicalize
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Honestly, I've got to give it to Python's [pathlib], which solves the problems I
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noted above. It splits the path API into `Path` and `PurePath`, the latter of
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which does not make any IO accesses. It also provides non-symlink-resolving and
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symlink-resolving variants of converting to absolute paths.
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[pathlib]: https://docs.python.org/3/library/pathlib.html
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