1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
# camino - UTF-8 encoded paths
[](https://crates.io/crates/camino)
[](https://crates.io/crates/camino)
[](https://docs.rs/camino)
[](https://camino-rs.github.io/camino/rustdoc/camino/)
[](LICENSE-APACHE)
[](LICENSE-MIT)
This repository contains the source code for `camino`, an extension of the `std::path` module that adds new
[`Utf8PathBuf`] and [`Utf8Path`] types.
## What is camino?
`camino`'s [`Utf8PathBuf`] and [`Utf8Path`] types are like the standard library's [`PathBuf`] and [`Path`] types, except
they are guaranteed to only contain UTF-8 encoded data. Therefore, they expose the ability to get their
contents as strings, they implement `Display`, etc.
The `std::path` types are not guaranteed to be valid UTF-8. This is the right decision for the standard library,
since it must be as general as possible. However, on all platforms, non-Unicode paths are vanishingly uncommon for a
number of reasons:
* Unicode won. There are still some legacy codebases that store paths in encodings like [Shift JIS], but most
have been converted to Unicode at this point.
* Unicode is the common subset of supported paths across Windows and Unix platforms. (On Windows, Rust stores paths
as [an extension to UTF-8](https://simonsapin.github.io/wtf-8/), and converts them to UTF-16 at Win32
API boundaries.)
* There are already many systems, such as Cargo, that only support UTF-8 paths. If your own tool interacts with any such
system, you can assume that paths are valid UTF-8 without creating any additional burdens on consumers.
* The ["makefile problem"](https://www.mercurial-scm.org/wiki/EncodingStrategy#The_.22makefile_problem.22) asks: given a
Makefile or other metadata file (such as `Cargo.toml`) that lists the names of other files, how should the names in
the Makefile be matched with the ones on disk? This has *no general, cross-platform solution* in systems that support
non-UTF-8 paths. However, restricting paths to UTF-8 eliminates this problem.
[Shift JIS]: https://en.wikipedia.org/wiki/Shift_JIS
Therefore, many programs that want to manipulate paths *do* assume they contain UTF-8 data, and convert them to `str`s
as necessary. However, because this invariant is not encoded in the `Path` type, conversions such as
`path.to_str().unwrap()` need to be repeated again and again, creating a frustrating experience.
Instead, `camino` allows you to check that your paths are UTF-8 *once*, and then manipulate them
as valid UTF-8 from there on, avoiding repeated lossy and confusing conversions.
## Examples
The documentation for [`Utf8PathBuf`] and [`Utf8Path`] contains several examples.
For examples of how to use `camino` with other libraries like `serde` and `clap`, see the [`camino-examples`] directory.
## API design
`camino` is a very thin wrapper around `std::path`. [`Utf8Path`] and [`Utf8PathBuf`] are drop-in replacements
for [`Path`] and [`PathBuf`].
Most APIs are the same, but those at the boundary with `str` are different. Some examples:
* `Path::to_str() -> Option<&str>` has been renamed to `Utf8Path::as_str() -> &str`.
* [`Utf8Path`] implements `Display`, and `Path::display()` has been removed.
* Iterating over a [`Utf8Path`] returns `&str`, not `&OsStr`.
Every [`Utf8Path`] is a valid [`Path`], so [`Utf8Path`] implements `AsRef<Path>`. Any APIs that accept `impl AsRef<Path>`
will continue to work with [`Utf8Path`] instances.
## Should you use camino?
`camino` trades off some utility for a great deal of simplicity. Whether `camino` is appropriate for a project or not
is ultimately a case-by-case decision. Here are some general guidelines that may help.
*You should consider using camino if...*
* **You're building portable, cross-platform software.** While both Unix and Windows platforms support different kinds
of non-Unicode paths, Unicode is the common subset that's supported across them.
* **Your system has files that contain the names of other files.** If you don't use UTF-8 paths, you will run into the
makefile problem described above, which has no general, cross-platform solution.
* **You're interacting with existing systems that already assume UTF-8 paths.** In that case you won't be adding any new
burdens on downstream consumers.
* **You're building something brand new and are willing to ask your users to rename their paths if necessary.** Projects
that don't have to worry about legacy compatibility have more flexibility in choosing what paths they support.
In general, using camino is the right choice for most projects.
*You should **NOT** use camino, if...*
* **You're writing a core system utility.** If you're writing, say, an `mv` or `cat` replacement, you should
**not** use camino. Instead, use [`std::path::Path`] and add extensive tests for non-UTF-8 paths.
* **You have legacy compatibility constraints.** For example, Git supports non-UTF-8 paths. If your tool needs to handle
arbitrary Git repositories, it should use its own path type that's a wrapper around `Vec<u8>`.
* [`std::path::Path`] supports arbitrary bytestrings [on Unix] but not on Windows.
* **There's some other reason you need to support non-UTF-8 paths.** Some tools like disk recovery utilities need to
handle potentially corrupt filenames: only being able to handle UTF-8 paths would greatly diminish their utility.
[on Unix]: https://doc.rust-lang.org/std/os/unix/ffi/index.html
## Optional features
By default, `camino` has **no dependencies** other than `std`. There are some optional features that enable
dependencies:
* `serde1` adds serde [`Serialize`] and [`Deserialize`] impls for [`Utf8PathBuf`] and [`Utf8Path`]
(zero-copy).
* `proptest1` adds [proptest](https://altsysrq.github.io/proptest-book/) [`Arbitrary`]
implementations for [`Utf8PathBuf`] and `Box<Utf8Path>`.
## Rust version support
The minimum supported Rust version (MSRV) for `camino` with default features is **1.34**. This project is tested in CI
against the latest stable version of Rust and the MSRV.
* *Stable APIs* added in later Rust versions are supported either through conditional compilation in `build.rs`, or through backfills that also work on older versions.
* *Deprecations* are kept in sync with the version of Rust they're added in.
* *Unstable APIs* are currently not supported. Please
[file an issue on GitHub](https://github.com/camino-rs/camino/issues/new) if you need an unstable API.
`camino` is designed to be a core library and has a conservative MSRV policy. MSRV increases will only happen for
a compelling enough reason, and will involve at least a minor version bump.
Optional features may pull in dependencies that require a newer version of Rust.
## License
This project is available under the terms of either the [Apache 2.0 license](LICENSE-APACHE) or the [MIT
license](LICENSE-MIT).
This project's documentation is adapted from [The Rust Programming Language](https://github.com/rust-lang/rust/), which is
available under the terms of either the [Apache 2.0 license](https://github.com/rust-lang/rust/blob/master/LICENSE-APACHE)
or the [MIT license](https://github.com/rust-lang/rust/blob/master/LICENSE-MIT).
[`Utf8PathBuf`]: https://docs.rs/camino/*/camino/struct.Utf8PathBuf.html
[`Utf8Path`]: https://docs.rs/camino/*/camino/struct.Utf8Path.html
[`PathBuf`]: https://doc.rust-lang.org/std/path/struct.PathBuf.html
[`Path`]: https://doc.rust-lang.org/std/path/struct.Path.html
[`std::path::Path`]: https://doc.rust-lang.org/std/path/struct.Path.html
[`Serialize`]: https://docs.rs/serde/1/serde/trait.Serialize.html
[`Deserialize`]: https://docs.rs/serde/1/serde/trait.Deserialize.html
[`camino-examples`]: https://github.com/camino-rs/camino/tree/main/camino-examples
[`Arbitrary`]: https://docs.rs/proptest/1/proptest/arbitrary/trait.Arbitrary.html
|
