which/
lib.rs

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1//! which
2//!
3//! A Rust equivalent of Unix command `which(1)`.
4//! # Example:
5//!
6//! To find which rustc executable binary is using:
7//!
8//! ```no_run
9//! use which::which;
10//! use std::path::PathBuf;
11//!
12//! let result = which("rustc").unwrap();
13//! assert_eq!(result, PathBuf::from("/usr/bin/rustc"));
14//!
15//! ```
16
17mod checker;
18mod error;
19mod finder;
20#[cfg(windows)]
21mod helper;
22
23#[cfg(feature = "regex")]
24use std::borrow::Borrow;
25use std::env;
26use std::fmt;
27use std::path;
28
29use std::ffi::{OsStr, OsString};
30
31use crate::checker::{CompositeChecker, ExecutableChecker, ExistedChecker};
32pub use crate::error::*;
33use crate::finder::Finder;
34
35/// Find an executable binary's path by name.
36///
37/// If given an absolute path, returns it if the file exists and is executable.
38///
39/// If given a relative path, returns an absolute path to the file if
40/// it exists and is executable.
41///
42/// If given a string without path separators, looks for a file named
43/// `binary_name` at each directory in `$PATH` and if it finds an executable
44/// file there, returns it.
45///
46/// # Example
47///
48/// ```no_run
49/// use which::which;
50/// use std::path::PathBuf;
51///
52/// let result = which::which("rustc").unwrap();
53/// assert_eq!(result, PathBuf::from("/usr/bin/rustc"));
54///
55/// ```
56pub fn which<T: AsRef<OsStr>>(binary_name: T) -> Result<path::PathBuf> {
57    which_all(binary_name).and_then(|mut i| i.next().ok_or(Error::CannotFindBinaryPath))
58}
59
60/// Find an executable binary's path by name, ignoring `cwd`.
61///
62/// If given an absolute path, returns it if the file exists and is executable.
63///
64/// Does not resolve relative paths.
65///
66/// If given a string without path separators, looks for a file named
67/// `binary_name` at each directory in `$PATH` and if it finds an executable
68/// file there, returns it.
69///
70/// # Example
71///
72/// ```no_run
73/// use which::which;
74/// use std::path::PathBuf;
75///
76/// let result = which::which_global("rustc").unwrap();
77/// assert_eq!(result, PathBuf::from("/usr/bin/rustc"));
78///
79/// ```
80pub fn which_global<T: AsRef<OsStr>>(binary_name: T) -> Result<path::PathBuf> {
81    which_all_global(binary_name).and_then(|mut i| i.next().ok_or(Error::CannotFindBinaryPath))
82}
83
84/// Find all binaries with `binary_name` using `cwd` to resolve relative paths.
85pub fn which_all<T: AsRef<OsStr>>(binary_name: T) -> Result<impl Iterator<Item = path::PathBuf>> {
86    let cwd = env::current_dir().ok();
87
88    let binary_checker = build_binary_checker();
89
90    let finder = Finder::new();
91
92    finder.find(binary_name, env::var_os("PATH"), cwd, binary_checker)
93}
94
95/// Find all binaries with `binary_name` ignoring `cwd`.
96pub fn which_all_global<T: AsRef<OsStr>>(
97    binary_name: T,
98) -> Result<impl Iterator<Item = path::PathBuf>> {
99    let binary_checker = build_binary_checker();
100
101    let finder = Finder::new();
102
103    finder.find(
104        binary_name,
105        env::var_os("PATH"),
106        Option::<&Path>::None,
107        binary_checker,
108    )
109}
110
111/// Find all binaries matching a regular expression in a the system PATH.
112///
113/// Only available when feature `regex` is enabled.
114///
115/// # Arguments
116///
117/// * `regex` - A regular expression to match binaries with
118///
119/// # Examples
120///
121/// Find Python executables:
122///
123/// ```no_run
124/// use regex::Regex;
125/// use which::which;
126/// use std::path::PathBuf;
127///
128/// let re = Regex::new(r"python\d$").unwrap();
129/// let binaries: Vec<PathBuf> = which::which_re(re).unwrap().collect();
130/// let python_paths = vec![PathBuf::from("/usr/bin/python2"), PathBuf::from("/usr/bin/python3")];
131/// assert_eq!(binaries, python_paths);
132/// ```
133///
134/// Find all cargo subcommand executables on the path:
135///
136/// ```
137/// use which::which_re;
138/// use regex::Regex;
139///
140/// which_re(Regex::new("^cargo-.*").unwrap()).unwrap()
141///     .for_each(|pth| println!("{}", pth.to_string_lossy()));
142/// ```
143#[cfg(feature = "regex")]
144pub fn which_re(regex: impl Borrow<Regex>) -> Result<impl Iterator<Item = path::PathBuf>> {
145    which_re_in(regex, env::var_os("PATH"))
146}
147
148/// Find `binary_name` in the path list `paths`, using `cwd` to resolve relative paths.
149pub fn which_in<T, U, V>(binary_name: T, paths: Option<U>, cwd: V) -> Result<path::PathBuf>
150where
151    T: AsRef<OsStr>,
152    U: AsRef<OsStr>,
153    V: AsRef<path::Path>,
154{
155    which_in_all(binary_name, paths, cwd)
156        .and_then(|mut i| i.next().ok_or(Error::CannotFindBinaryPath))
157}
158
159/// Find all binaries matching a regular expression in a list of paths.
160///
161/// Only available when feature `regex` is enabled.
162///
163/// # Arguments
164///
165/// * `regex` - A regular expression to match binaries with
166/// * `paths` - A string containing the paths to search
167///             (separated in the same way as the PATH environment variable)
168///
169/// # Examples
170///
171/// ```no_run
172/// use regex::Regex;
173/// use which::which;
174/// use std::path::PathBuf;
175///
176/// let re = Regex::new(r"python\d$").unwrap();
177/// let paths = Some("/usr/bin:/usr/local/bin");
178/// let binaries: Vec<PathBuf> = which::which_re_in(re, paths).unwrap().collect();
179/// let python_paths = vec![PathBuf::from("/usr/bin/python2"), PathBuf::from("/usr/bin/python3")];
180/// assert_eq!(binaries, python_paths);
181/// ```
182#[cfg(feature = "regex")]
183pub fn which_re_in<T>(
184    regex: impl Borrow<Regex>,
185    paths: Option<T>,
186) -> Result<impl Iterator<Item = path::PathBuf>>
187where
188    T: AsRef<OsStr>,
189{
190    let binary_checker = build_binary_checker();
191
192    let finder = Finder::new();
193
194    finder.find_re(regex, paths, binary_checker)
195}
196
197/// Find all binaries with `binary_name` in the path list `paths`, using `cwd` to resolve relative paths.
198pub fn which_in_all<T, U, V>(
199    binary_name: T,
200    paths: Option<U>,
201    cwd: V,
202) -> Result<impl Iterator<Item = path::PathBuf>>
203where
204    T: AsRef<OsStr>,
205    U: AsRef<OsStr>,
206    V: AsRef<path::Path>,
207{
208    let binary_checker = build_binary_checker();
209
210    let finder = Finder::new();
211
212    finder.find(binary_name, paths, Some(cwd), binary_checker)
213}
214
215/// Find all binaries with `binary_name` in the path list `paths`, ignoring `cwd`.
216pub fn which_in_global<T, U>(
217    binary_name: T,
218    paths: Option<U>,
219) -> Result<impl Iterator<Item = path::PathBuf>>
220where
221    T: AsRef<OsStr>,
222    U: AsRef<OsStr>,
223{
224    let binary_checker = build_binary_checker();
225
226    let finder = Finder::new();
227
228    finder.find(binary_name, paths, Option::<&Path>::None, binary_checker)
229}
230
231fn build_binary_checker() -> CompositeChecker {
232    CompositeChecker::new()
233        .add_checker(Box::new(ExistedChecker::new()))
234        .add_checker(Box::new(ExecutableChecker::new()))
235}
236
237/// A wrapper containing all functionality in this crate.
238pub struct WhichConfig {
239    cwd: Option<either::Either<bool, path::PathBuf>>,
240    custom_path_list: Option<OsString>,
241    binary_name: Option<OsString>,
242    #[cfg(feature = "regex")]
243    regex: Option<Regex>,
244}
245
246impl Default for WhichConfig {
247    fn default() -> Self {
248        Self {
249            cwd: Some(either::Either::Left(true)),
250            custom_path_list: None,
251            binary_name: None,
252            #[cfg(feature = "regex")]
253            regex: None,
254        }
255    }
256}
257
258#[cfg(feature = "regex")]
259type Regex = regex::Regex;
260
261#[cfg(not(feature = "regex"))]
262type Regex = ();
263
264impl WhichConfig {
265    pub fn new() -> Self {
266        Self::default()
267    }
268
269    /// Whether or not to use the current working directory. `true` by default.
270    ///
271    /// # Panics
272    ///
273    /// If regex was set previously, and you've just passed in `use_cwd: true`, this will panic.
274    pub fn system_cwd(mut self, use_cwd: bool) -> Self {
275        #[cfg(feature = "regex")]
276        if self.regex.is_some() && use_cwd {
277            panic!("which can't use regex and cwd at the same time!")
278        }
279        self.cwd = Some(either::Either::Left(use_cwd));
280        self
281    }
282
283    /// Sets a custom path for resolving relative paths.
284    ///
285    /// # Panics
286    ///
287    /// If regex was set previously, this will panic.
288    pub fn custom_cwd(mut self, cwd: path::PathBuf) -> Self {
289        #[cfg(feature = "regex")]
290        if self.regex.is_some() {
291            panic!("which can't use regex and cwd at the same time!")
292        }
293        self.cwd = Some(either::Either::Right(cwd));
294        self
295    }
296
297    /// Sets the path name regex to search for. You ***MUST*** call this, or [`Self::binary_name`] prior to searching.
298    ///
299    /// When `Regex` is disabled this function takes the unit type as a stand in. The parameter will change when
300    /// `Regex` is enabled.
301    ///
302    /// # Panics
303    ///
304    /// If the `regex` feature wasn't turned on for this crate this will always panic. Additionally if a
305    /// `cwd` (aka current working directory) or `binary_name` was set previously, this will panic, as those options
306    /// are incompatible with `regex`.
307    #[allow(unused_variables)]
308    #[allow(unused_mut)]
309    pub fn regex(mut self, regex: Regex) -> Self {
310        #[cfg(not(feature = "regex"))]
311        {
312            panic!("which's regex feature was not enabled in your Cargo.toml!")
313        }
314        #[cfg(feature = "regex")]
315        {
316            if self.cwd != Some(either::Either::Left(false)) && self.cwd.is_some() {
317                panic!("which can't use regex and cwd at the same time!")
318            }
319            if self.binary_name.is_some() {
320                panic!("which can't use `binary_name` and `regex` at the same time!");
321            }
322            self.regex = Some(regex);
323            self
324        }
325    }
326
327    /// Sets the path name to search for. You ***MUST*** call this, or [`Self::regex`] prior to searching.
328    ///
329    /// # Panics
330    ///
331    /// If a `regex` was set previously this will panic as this is not compatible with `regex`.
332    pub fn binary_name(mut self, name: OsString) -> Self {
333        #[cfg(feature = "regex")]
334        if self.regex.is_some() {
335            panic!("which can't use `binary_name` and `regex` at the same time!");
336        }
337        self.binary_name = Some(name);
338        self
339    }
340
341    /// Uses the given string instead of the `PATH` env variable.
342    pub fn custom_path_list(mut self, custom_path_list: OsString) -> Self {
343        self.custom_path_list = Some(custom_path_list);
344        self
345    }
346
347    /// Uses the `PATH` env variable. Enabled by default.
348    pub fn system_path_list(mut self) -> Self {
349        self.custom_path_list = None;
350        self
351    }
352
353    /// Finishes configuring, runs the query and returns the first result.
354    pub fn first_result(self) -> Result<path::PathBuf> {
355        self.all_results()
356            .and_then(|mut i| i.next().ok_or(Error::CannotFindBinaryPath))
357    }
358
359    /// Finishes configuring, runs the query and returns all results.
360    pub fn all_results(self) -> Result<impl Iterator<Item = path::PathBuf>> {
361        let binary_checker = build_binary_checker();
362
363        let finder = Finder::new();
364
365        let paths = self.custom_path_list.or_else(|| env::var_os("PATH"));
366
367        #[cfg(feature = "regex")]
368        if let Some(regex) = self.regex {
369            return finder
370                .find_re(regex, paths, binary_checker)
371                .map(|i| Box::new(i) as Box<dyn Iterator<Item = path::PathBuf>>);
372        }
373
374        let cwd = match self.cwd {
375            Some(either::Either::Left(false)) => None,
376            Some(either::Either::Right(custom)) => Some(custom),
377            None | Some(either::Either::Left(true)) => env::current_dir().ok(),
378        };
379
380        finder
381            .find(
382                self.binary_name.expect(
383                    "binary_name not set! You must set binary_name or regex before searching!",
384                ),
385                paths,
386                cwd,
387                binary_checker,
388            )
389            .map(|i| Box::new(i) as Box<dyn Iterator<Item = path::PathBuf>>)
390    }
391}
392
393/// An owned, immutable wrapper around a `PathBuf` containing the path of an executable.
394///
395/// The constructed `PathBuf` is the output of `which` or `which_in`, but `which::Path` has the
396/// advantage of being a type distinct from `std::path::Path` and `std::path::PathBuf`.
397///
398/// It can be beneficial to use `which::Path` instead of `std::path::Path` when you want the type
399/// system to enforce the need for a path that exists and points to a binary that is executable.
400///
401/// Since `which::Path` implements `Deref` for `std::path::Path`, all methods on `&std::path::Path`
402/// are also available to `&which::Path` values.
403#[derive(Clone, PartialEq, Eq)]
404pub struct Path {
405    inner: path::PathBuf,
406}
407
408impl Path {
409    /// Returns the path of an executable binary by name.
410    ///
411    /// This calls `which` and maps the result into a `Path`.
412    pub fn new<T: AsRef<OsStr>>(binary_name: T) -> Result<Path> {
413        which(binary_name).map(|inner| Path { inner })
414    }
415
416    /// Returns the paths of all executable binaries by a name.
417    ///
418    /// this calls `which_all` and maps the results into `Path`s.
419    pub fn all<T: AsRef<OsStr>>(binary_name: T) -> Result<impl Iterator<Item = Path>> {
420        which_all(binary_name).map(|inner| inner.map(|inner| Path { inner }))
421    }
422
423    /// Returns the path of an executable binary by name in the path list `paths` and using the
424    /// current working directory `cwd` to resolve relative paths.
425    ///
426    /// This calls `which_in` and maps the result into a `Path`.
427    pub fn new_in<T, U, V>(binary_name: T, paths: Option<U>, cwd: V) -> Result<Path>
428    where
429        T: AsRef<OsStr>,
430        U: AsRef<OsStr>,
431        V: AsRef<path::Path>,
432    {
433        which_in(binary_name, paths, cwd).map(|inner| Path { inner })
434    }
435
436    /// Returns all paths of an executable binary by name in the path list `paths` and using the
437    /// current working directory `cwd` to resolve relative paths.
438    ///
439    /// This calls `which_in_all` and maps the results into a `Path`.
440    pub fn all_in<T, U, V>(
441        binary_name: T,
442        paths: Option<U>,
443        cwd: V,
444    ) -> Result<impl Iterator<Item = Path>>
445    where
446        T: AsRef<OsStr>,
447        U: AsRef<OsStr>,
448        V: AsRef<path::Path>,
449    {
450        which_in_all(binary_name, paths, cwd).map(|inner| inner.map(|inner| Path { inner }))
451    }
452
453    /// Returns a reference to a `std::path::Path`.
454    pub fn as_path(&self) -> &path::Path {
455        self.inner.as_path()
456    }
457
458    /// Consumes the `which::Path`, yielding its underlying `std::path::PathBuf`.
459    pub fn into_path_buf(self) -> path::PathBuf {
460        self.inner
461    }
462}
463
464impl fmt::Debug for Path {
465    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
466        fmt::Debug::fmt(&self.inner, f)
467    }
468}
469
470impl std::ops::Deref for Path {
471    type Target = path::Path;
472
473    fn deref(&self) -> &path::Path {
474        self.inner.deref()
475    }
476}
477
478impl AsRef<path::Path> for Path {
479    fn as_ref(&self) -> &path::Path {
480        self.as_path()
481    }
482}
483
484impl AsRef<OsStr> for Path {
485    fn as_ref(&self) -> &OsStr {
486        self.as_os_str()
487    }
488}
489
490impl PartialEq<path::PathBuf> for Path {
491    fn eq(&self, other: &path::PathBuf) -> bool {
492        self.inner == *other
493    }
494}
495
496impl PartialEq<Path> for path::PathBuf {
497    fn eq(&self, other: &Path) -> bool {
498        *self == other.inner
499    }
500}
501
502/// An owned, immutable wrapper around a `PathBuf` containing the _canonical_ path of an
503/// executable.
504///
505/// The constructed `PathBuf` is the result of `which` or `which_in` followed by
506/// `Path::canonicalize`, but `CanonicalPath` has the advantage of being a type distinct from
507/// `std::path::Path` and `std::path::PathBuf`.
508///
509/// It can be beneficial to use `CanonicalPath` instead of `std::path::Path` when you want the type
510/// system to enforce the need for a path that exists, points to a binary that is executable, is
511/// absolute, has all components normalized, and has all symbolic links resolved
512///
513/// Since `CanonicalPath` implements `Deref` for `std::path::Path`, all methods on
514/// `&std::path::Path` are also available to `&CanonicalPath` values.
515#[derive(Clone, PartialEq, Eq)]
516pub struct CanonicalPath {
517    inner: path::PathBuf,
518}
519
520impl CanonicalPath {
521    /// Returns the canonical path of an executable binary by name.
522    ///
523    /// This calls `which` and `Path::canonicalize` and maps the result into a `CanonicalPath`.
524    pub fn new<T: AsRef<OsStr>>(binary_name: T) -> Result<CanonicalPath> {
525        which(binary_name)
526            .and_then(|p| p.canonicalize().map_err(|_| Error::CannotCanonicalize))
527            .map(|inner| CanonicalPath { inner })
528    }
529
530    /// Returns the canonical paths of an executable binary by name.
531    ///
532    /// This calls `which_all` and `Path::canonicalize` and maps the results into `CanonicalPath`s.
533    pub fn all<T: AsRef<OsStr>>(
534        binary_name: T,
535    ) -> Result<impl Iterator<Item = Result<CanonicalPath>>> {
536        which_all(binary_name).map(|inner| {
537            inner.map(|inner| {
538                inner
539                    .canonicalize()
540                    .map_err(|_| Error::CannotCanonicalize)
541                    .map(|inner| CanonicalPath { inner })
542            })
543        })
544    }
545
546    /// Returns the canonical path of an executable binary by name in the path list `paths` and
547    /// using the current working directory `cwd` to resolve relative paths.
548    ///
549    /// This calls `which_in` and `Path::canonicalize` and maps the result into a `CanonicalPath`.
550    pub fn new_in<T, U, V>(binary_name: T, paths: Option<U>, cwd: V) -> Result<CanonicalPath>
551    where
552        T: AsRef<OsStr>,
553        U: AsRef<OsStr>,
554        V: AsRef<path::Path>,
555    {
556        which_in(binary_name, paths, cwd)
557            .and_then(|p| p.canonicalize().map_err(|_| Error::CannotCanonicalize))
558            .map(|inner| CanonicalPath { inner })
559    }
560
561    /// Returns all of the canonical paths of an executable binary by name in the path list `paths` and
562    /// using the current working directory `cwd` to resolve relative paths.
563    ///
564    /// This calls `which_in_all` and `Path::canonicalize` and maps the result into a `CanonicalPath`.
565    pub fn all_in<T, U, V>(
566        binary_name: T,
567        paths: Option<U>,
568        cwd: V,
569    ) -> Result<impl Iterator<Item = Result<CanonicalPath>>>
570    where
571        T: AsRef<OsStr>,
572        U: AsRef<OsStr>,
573        V: AsRef<path::Path>,
574    {
575        which_in_all(binary_name, paths, cwd).map(|inner| {
576            inner.map(|inner| {
577                inner
578                    .canonicalize()
579                    .map_err(|_| Error::CannotCanonicalize)
580                    .map(|inner| CanonicalPath { inner })
581            })
582        })
583    }
584
585    /// Returns a reference to a `std::path::Path`.
586    pub fn as_path(&self) -> &path::Path {
587        self.inner.as_path()
588    }
589
590    /// Consumes the `which::CanonicalPath`, yielding its underlying `std::path::PathBuf`.
591    pub fn into_path_buf(self) -> path::PathBuf {
592        self.inner
593    }
594}
595
596impl fmt::Debug for CanonicalPath {
597    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
598        fmt::Debug::fmt(&self.inner, f)
599    }
600}
601
602impl std::ops::Deref for CanonicalPath {
603    type Target = path::Path;
604
605    fn deref(&self) -> &path::Path {
606        self.inner.deref()
607    }
608}
609
610impl AsRef<path::Path> for CanonicalPath {
611    fn as_ref(&self) -> &path::Path {
612        self.as_path()
613    }
614}
615
616impl AsRef<OsStr> for CanonicalPath {
617    fn as_ref(&self) -> &OsStr {
618        self.as_os_str()
619    }
620}
621
622impl PartialEq<path::PathBuf> for CanonicalPath {
623    fn eq(&self, other: &path::PathBuf) -> bool {
624        self.inner == *other
625    }
626}
627
628impl PartialEq<CanonicalPath> for path::PathBuf {
629    fn eq(&self, other: &CanonicalPath) -> bool {
630        *self == other.inner
631    }
632}
which/lib.rs

which/
lib.rs
