simple_path/
simple_path.rs

1#![cfg_attr(not(target_os = "windows"), allow(unused))]
2use crate::Display;
3#[cfg(windows)]
4use crate::{PathExt, UncPath, Volumes};
5use std::{
6    borrow::Cow,
7    fs, io,
8    path::{Path, PathBuf, StripPrefixError},
9};
10
11/// Simplifies [Win32 File Namespaces] paths (the "`\\?\`" prefix)
12/// for better readability and compatibility.
13///
14/// The following code is a snap-in replacement of [`fs::canonicalize`].
15/// ```no_run
16/// # use simple_path::SimplePath;
17/// # let path = "";
18/// SimplePath::default().canonicalize(path);
19/// ```
20///
21/// If you have `net use Z: \\server\share`:
22/// | | `C:\dir` | `Z:\x` |
23/// | --- | --- | --- |
24/// | [`fs::canonicalize`] | `\\?\C:\dir` | `\\?\UNC\server\share\x` |
25/// | `SimplePath` | `C:\dir` | `\\server\share\x` |
26/// | `SimplePath` with [`map_to_drive`] | `C:\dir` | `Z:\x` |
27///
28/// [`map_to_drive`]: `SimplePath::map_to_drive`
29/// [Win32 File Namespaces]: https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file#win32-file-namespaces
30#[derive(Clone, Debug, Default)]
31pub struct SimplePath {
32    /// Disallow simplifications
33    /// if the result is a "long path" (longer than 260 characters).
34    /// Initially `false`.
35    ///
36    /// Long paths may not be supported by some programs and APIs.
37    /// In such cases, using the [Win32 File Namespaces] (the "`\\?\`" prefix)
38    /// can often work around the limitation.
39    /// Setting this option to `true` can improve
40    /// the compatibility with such cases.
41    ///
42    /// On the other hand, some other programs such as PowerShell v7
43    /// can handle long paths,
44    /// but they can't handle the "`\\?\`" prefix.
45    /// They work best with `false`.
46    ///
47    /// Please also see the [Maximum Path Length Limitation].
48    ///
49    /// [Maximum Path Length Limitation]: https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
50    /// [Win32 File Namespaces]: https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file#win32-file-namespaces
51    pub disallow_long: bool,
52
53    /// Simplify all long UNC paths (prefixed by "`\\?\UNC\`").
54    /// Initially `false`.
55    ///
56    /// Technically speaking,
57    /// since the "`\\?\`" prefix ([Win32 File Namespaces])
58    /// disables all string parsing and
59    /// sends the following string directly to the file system,
60    /// simplifying the path is not always guaranteed to be safe or equivalent.
61    ///
62    /// For this reason,
63    /// the `SimplePath` simplifies connected network shares only by default.
64    /// Set this option to `true`
65    /// to simplify all paths prefixed by "`\\?\UNC\`".
66    ///
67    /// Please also see the [safety] note.
68    ///
69    /// # Examples
70    /// ```
71    /// # use simple_path::SimplePath;
72    /// # use std::path::Path;
73    /// let path = Path::new(r"\\?\UNC\server\share\dir");
74    /// let simple = SimplePath { allow_unknown_unc: true, ..Default::default() };
75    /// #[cfg(windows)]
76    /// assert_eq!(&*simple.simplify(path).unwrap().unwrap(), r"\\server\share\dir");
77    /// ```
78    ///
79    /// [safety]: https://github.com/kojiishi/simple-path#safety-and-equivalence
80    /// [Win32 File Namespaces]: https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file#win32-file-namespaces
81    pub allow_unknown_unc: bool,
82
83    /// Map to network share drive names when possible.
84    /// Initially `false`.
85    ///
86    /// # Examples
87    ///
88    /// ```
89    /// # use simple_path::SimplePath;
90    /// # fn test() -> std::io::Result<()> {
91    /// let path = "file.txt";
92    /// let simple = SimplePath { map_to_drive: true, ..Default::default() };
93    /// let canonicalized = simple.canonicalize(path)?;
94    /// # Ok(())
95    /// # }
96    /// ```
97    /// If the `file.txt` is in a network drive,
98    /// the result is `Z:\dir\file.txt`
99    /// instead of `\\server\share\dir\file.txt`.
100    ///
101    /// The following code tries to preserve the original form of the `path`.
102    /// ```
103    /// # use simple_path::SimplePath;
104    /// # fn test(path: &std::path::Path) -> std::io::Result<()> {
105    /// SimplePath {
106    ///     map_to_drive: !path.as_os_str().as_encoded_bytes().starts_with(br"\\"),
107    ///     ..Default::default()
108    /// }.canonicalize(path)?;
109    /// # Ok(())
110    /// # }
111    /// ```
112    pub map_to_drive: bool,
113
114    /// Skip the [`dunce`] simplification.
115    /// Initially `false`.
116    ///
117    /// [`dunce`]: https://crates.io/crates/dunce
118    pub skip_dunce: bool,
119
120    /// It is highly recommended to always use `, ..Default::default()`.
121    /// Otherwise builds fail when new fields are added.
122    ///
123    /// This field is not used in any ways,
124    /// but exists to allow using `, ..Default::default()`
125    /// even when all other fields are specified.
126    pub _unused: bool,
127
128    #[cfg(all(test, windows))]
129    volumes: Option<Volumes>,
130}
131
132impl SimplePath {
133    #[cfg(all(test, windows))]
134    pub(crate) fn mock() -> SimplePath {
135        SimplePath {
136            volumes: Some(Volumes::mock()),
137            ..Default::default()
138        }
139    }
140
141    /// A snap-in replacement for [`fs::canonicalize`].
142    /// It calls [`fs::canonicalize`] and [`simplify`].
143    ///
144    /// On other platforms than Windows,
145    /// this is equivalent to [`fs::canonicalize`].
146    ///
147    /// # Examples
148    /// ```
149    /// # fn test(path: &std::path::Path) -> std::io::Result<()> {
150    /// use simple_path::SimplePath;
151    /// let canonicalized = SimplePath::default().canonicalize(path)?;
152    /// println!("{}", canonicalized.display());
153    /// # Ok(()) }
154    /// ```
155    ///
156    /// [`fs::canonicalize`]: https://doc.rust-lang.org/std/fs/fn.canonicalize.html
157    /// [`simplify`]: SimplePath::simplify
158    #[inline]
159    pub fn canonicalize(&self, path: impl AsRef<Path>) -> io::Result<PathBuf> {
160        let canonicalized = fs::canonicalize(path)?;
161        #[cfg(windows)]
162        if let Some(simplified) = self.simplify(&canonicalized)? {
163            return Ok(simplified.into_owned());
164        }
165        Ok(canonicalized)
166    }
167
168    /// Try to simplify the given `path`.
169    ///
170    /// Returns `Ok(None)`
171    /// if no simplification is applied,
172    /// or on other platforms than Windows.
173    #[inline]
174    pub fn simplify<'a>(&self, path: &'a Path) -> io::Result<Option<Cow<'a, Path>>> {
175        #[cfg(windows)]
176        return self._simplify(path).map_err(io_error_from_anyhow);
177        #[cfg(not(windows))]
178        Ok(None)
179    }
180
181    #[cfg(windows)]
182    fn _simplify<'a>(&self, path: &'a Path) -> anyhow::Result<Option<Cow<'a, Path>>> {
183        // If it starts with the `\\?\UNC\` prefix.
184        if let Ok(unc) = UncPath::try_from(path)
185            && unc.is_file_namespace_unc()
186        {
187            // Try mapped network drives.
188            let drive_path = if !self.allow_unknown_unc || self.map_to_drive {
189                self.drive_path(path)?
190            } else {
191                None
192            };
193            if self.map_to_drive
194                && let Some(drive_path) = &drive_path
195                && drive_path.has_drive()
196                && !drive_path.has_invalid_chars()
197                && (!self.disallow_long || !drive_path.is_longer_than_max_path())
198            {
199                return Ok(Some(Cow::Owned(drive_path.to_path_buf())));
200            }
201
202            // Try short UNC (`\\server\share`).
203            if (self.allow_unknown_unc || drive_path.is_some())
204                && let Some(short_unc) = unc.to_short_unc()
205                && !short_unc.has_invalid_chars()
206                && (!self.disallow_long || !short_unc.is_longer_than_win_max_path())
207            {
208                return Ok(Some(Cow::Owned(short_unc)));
209            }
210        }
211
212        // Try `dunce::simplified`.
213        if !self.skip_dunce {
214            let simplified = dunce::simplified(path);
215            if !std::ptr::eq(path, simplified) {
216                return Ok(Some(Cow::Borrowed(simplified)));
217            }
218        }
219        Ok(None)
220    }
221
222    #[cfg(windows)]
223    #[inline]
224    fn drive_path<'a>(&self, path: &'a Path) -> anyhow::Result<Option<crate::DrivePath<'a>>> {
225        #[cfg(test)]
226        if let Some(volumes) = &self.volumes {
227            return Ok(volumes._drive_path(path));
228        }
229        Volumes::drive_path(path)
230    }
231
232    /// Refreshes the cached information.
233    pub fn refresh() -> io::Result<()> {
234        #[cfg(windows)]
235        Volumes::refresh().map_err(io_error_from_anyhow)?;
236        Ok(())
237    }
238
239    /// Returns an object that implements [`Display`][`core::fmt::Display`]
240    /// for printing simplified paths.
241    ///
242    /// # Examples
243    ///
244    /// ```
245    /// # use std::path::Path;
246    /// # use simple_path::SimplePath;
247    /// # fn test() -> std::io::Result<()> {
248    /// let path = Path::new("file").canonicalize()?;
249    /// println!("{}", SimplePath::default().display(&path));
250    /// # Ok(())
251    /// # }
252    /// ```
253    pub fn display<'a>(&'a self, path: &'a Path) -> Display<'a> {
254        Display::new(self, path)
255    }
256
257    /// A snap-in replacement for [`Path::strip_prefix`]
258    /// with a fix for [a leading directory separator "`\`" left for UNC paths
259    /// on Windows](https://github.com/rust-lang/rust/issues/155183).
260    ///
261    /// # Examples
262    ///
263    /// ```
264    /// # use std::path::{Path, StripPrefixError};
265    /// # use simple_path::SimplePath;
266    /// # fn t<'a>(path: &'a Path, base: &'a Path) -> Result<&'a Path, StripPrefixError> {
267    /// SimplePath::strip_prefix(path, base)
268    /// # }
269    /// ```
270    pub fn strip_prefix(path: &Path, base: impl AsRef<Path>) -> Result<&Path, StripPrefixError> {
271        #[cfg(windows)]
272        return PathExt::strip_prefix_fix(path, base);
273        #[cfg(not(windows))]
274        path.strip_prefix(base)
275    }
276}
277
278fn io_error_from_anyhow(error: anyhow::Error) -> io::Error {
279    match error.downcast::<io::Error>() {
280        Ok(io_error) => io_error,
281        Err(other_error) => io::Error::other(other_error),
282    }
283}
284
285#[cfg(test)]
286mod tests {
287    use super::*;
288
289    #[cfg(windows)]
290    #[test]
291    fn simplify_drive() {
292        let mut simple = SimplePath::mock();
293        assert_eq!(simple.simplify(Path::new(r"C:\foo")).unwrap(), None);
294        simple.allow_unknown_unc = true;
295        assert_eq!(simple.simplify(Path::new(r"C:\foo")).unwrap(), None);
296    }
297
298    #[cfg(windows)]
299    #[test]
300    fn simplify_drive_unc() {
301        let mut simple = SimplePath::mock();
302        let path = Path::new(r"\\?\UNC\server\share\foo");
303        let path2 = Path::new(r"\\?\UNC\server2\share2\foo2");
304        assert_eq!(
305            simple.simplify(path).unwrap(),
306            Some(Cow::Owned(PathBuf::from(r"\\server\share\foo")))
307        );
308        assert_eq!(
309            simple.simplify(path2).unwrap(),
310            Some(Cow::Owned(PathBuf::from(r"\\server2\share2\foo2")))
311        );
312
313        simple.map_to_drive = true;
314        assert_eq!(
315            simple.simplify(path).unwrap(),
316            Some(Cow::Owned(PathBuf::from(r"X:\foo")))
317        );
318        assert_eq!(
319            simple.simplify(path2).unwrap(),
320            Some(Cow::Owned(PathBuf::from(r"Z:\foo2")))
321        );
322    }
323
324    #[cfg(windows)]
325    #[test]
326    fn simplify_dunce() {
327        let simple = SimplePath::default();
328        assert_eq!(
329            simple.simplify(Path::new(r"\\?\C:\foo")).unwrap(),
330            Some(Cow::Borrowed(Path::new(r"C:\foo")))
331        );
332    }
333
334    #[cfg(windows)]
335    #[test]
336    fn simplify_dunce_skip() {
337        let simple = SimplePath {
338            skip_dunce: true,
339            ..Default::default()
340        };
341        assert_eq!(simple.simplify(Path::new(r"\\?\C:\foo")).unwrap(), None);
342    }
343
344    #[cfg(windows)]
345    #[test]
346    fn simplify_unmapped_connected_share() {
347        let mut simple = SimplePath::mock();
348        let path = Path::new(r"\\?\UNC\server0\share0\foo");
349        assert_eq!(
350            simple.simplify(path).unwrap(),
351            Some(Cow::Owned(PathBuf::from(r"\\server0\share0\foo")))
352        );
353
354        // Even with map_to_drive = true, it should simplify to the UNC path,
355        // because the drive letter is '\0'.
356        simple.map_to_drive = true;
357        assert_eq!(
358            simple.simplify(path).unwrap(),
359            Some(Cow::Owned(PathBuf::from(r"\\server0\share0\foo")))
360        );
361    }
362
363    #[cfg(windows)]
364    #[test]
365    fn simplify_unknown_unc() -> anyhow::Result<()> {
366        let mut simple = SimplePath::mock();
367        let unknown = Path::new(r"\\?\UNC\server\unknown\foo");
368        let mapped = Path::new(r"\\?\UNC\server\share\foo");
369        assert_eq!(simple.simplify(unknown)?, None);
370
371        // `unknown` should be simplified if `allow_unknown_unc`.
372        simple.allow_unknown_unc = true;
373        assert_eq!(
374            simple.simplify(unknown)?,
375            Some(Cow::Owned(PathBuf::from(r"\\server\unknown\foo")))
376        );
377        assert_eq!(
378            simple.simplify(mapped)?,
379            Some(Cow::Owned(PathBuf::from(r"\\server\share\foo")))
380        );
381
382        // `map_to_drive` should still be in effect.
383        simple.map_to_drive = true;
384        assert_eq!(
385            simple.simplify(mapped)?,
386            Some(Cow::Owned(PathBuf::from(r"X:\foo")))
387        );
388
389        // `allow_unknown_unc` should simplify only for "`\\?\UNC\`".
390        assert_eq!(simple.simplify(Path::new(r"\\.\COM1:"))?, None);
391        simple.skip_dunce = true;
392        assert_eq!(simple.simplify(Path::new(r"\\?\C:\foo"))?, None);
393        Ok(())
394    }
395}
simple_path/simple_path.rs

simple_path/
simple_path.rs
