1//! Filesystem manipulation operations.
2//!
3//! This module contains basic methods to manipulate the contents of the local
4//! filesystem. All methods in this module represent cross-platform filesystem
5//! operations. Extra platform-specific functionality can be found in the
6//! extension traits of `std::os::$platform`.
7
8#![stable(feature = "rust1", since = "1.0.0")]
9#![deny(unsafe_op_in_unsafe_fn)]
10
11#[cfg(all(test, not(any(target_os = "emscripten", target_env = "sgx", target_os = "xous"))))]
12mod tests;
13
14use crate::ffi::OsString;
15use crate::fmt;
16use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
17use crate::path::{Path, PathBuf};
18use crate::sealed::Sealed;
19use crate::sync::Arc;
20use crate::sys::fs as fs_imp;
21use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
22use crate::time::SystemTime;
23
24/// An object providing access to an open file on the filesystem.
25///
26/// An instance of a `File` can be read and/or written depending on what options
27/// it was opened with. Files also implement [`Seek`] to alter the logical cursor
28/// that the file contains internally.
29///
30/// Files are automatically closed when they go out of scope. Errors detected
31/// on closing are ignored by the implementation of `Drop`. Use the method
32/// [`sync_all`] if these errors must be manually handled.
33///
34/// `File` does not buffer reads and writes. For efficiency, consider wrapping the
35/// file in a [`BufReader`] or [`BufWriter`] when performing many small [`read`]
36/// or [`write`] calls, unless unbuffered reads and writes are required.
37///
38/// # Examples
39///
40/// Creates a new file and write bytes to it (you can also use [`write()`]):
41///
42/// ```no_run
43/// use std::fs::File;
44/// use std::io::prelude::*;
45///
46/// fn main() -> std::io::Result<()> {
47/// let mut file = File::create("foo.txt")?;
48/// file.write_all(b"Hello, world!")?;
49/// Ok(())
50/// }
51/// ```
52///
53/// Read the contents of a file into a [`String`] (you can also use [`read`]):
54///
55/// ```no_run
56/// use std::fs::File;
57/// use std::io::prelude::*;
58///
59/// fn main() -> std::io::Result<()> {
60/// let mut file = File::open("foo.txt")?;
61/// let mut contents = String::new();
62/// file.read_to_string(&mut contents)?;
63/// assert_eq!(contents, "Hello, world!");
64/// Ok(())
65/// }
66/// ```
67///
68/// Using a buffered [`Read`]er:
69///
70/// ```no_run
71/// use std::fs::File;
72/// use std::io::BufReader;
73/// use std::io::prelude::*;
74///
75/// fn main() -> std::io::Result<()> {
76/// let file = File::open("foo.txt")?;
77/// let mut buf_reader = BufReader::new(file);
78/// let mut contents = String::new();
79/// buf_reader.read_to_string(&mut contents)?;
80/// assert_eq!(contents, "Hello, world!");
81/// Ok(())
82/// }
83/// ```
84///
85/// Note that, although read and write methods require a `&mut File`, because
86/// of the interfaces for [`Read`] and [`Write`], the holder of a `&File` can
87/// still modify the file, either through methods that take `&File` or by
88/// retrieving the underlying OS object and modifying the file that way.
89/// Additionally, many operating systems allow concurrent modification of files
90/// by different processes. Avoid assuming that holding a `&File` means that the
91/// file will not change.
92///
93/// # Platform-specific behavior
94///
95/// On Windows, the implementation of [`Read`] and [`Write`] traits for `File`
96/// perform synchronous I/O operations. Therefore the underlying file must not
97/// have been opened for asynchronous I/O (e.g. by using `FILE_FLAG_OVERLAPPED`).
98///
99/// [`BufReader`]: io::BufReader
100/// [`BufWriter`]: io::BufReader
101/// [`sync_all`]: File::sync_all
102/// [`write`]: File::write
103/// [`read`]: File::read
104#[stable(feature = "rust1", since = "1.0.0")]
105#[cfg_attr(not(test), rustc_diagnostic_item = "File")]
106pub struct File {
107 inner: fs_imp::File,
108}
109
110/// Metadata information about a file.
111///
112/// This structure is returned from the [`metadata`] or
113/// [`symlink_metadata`] function or method and represents known
114/// metadata about a file such as its permissions, size, modification
115/// times, etc.
116#[stable(feature = "rust1", since = "1.0.0")]
117#[derive(Clone)]
118pub struct Metadata(fs_imp::FileAttr);
119
120/// Iterator over the entries in a directory.
121///
122/// This iterator is returned from the [`read_dir`] function of this module and
123/// will yield instances of <code>[io::Result]<[DirEntry]></code>. Through a [`DirEntry`]
124/// information like the entry's path and possibly other metadata can be
125/// learned.
126///
127/// The order in which this iterator returns entries is platform and filesystem
128/// dependent.
129///
130/// # Errors
131///
132/// This [`io::Result`] will be an [`Err`] if there's some sort of intermittent
133/// IO error during iteration.
134#[stable(feature = "rust1", since = "1.0.0")]
135#[derive(Debug)]
136pub struct ReadDir(fs_imp::ReadDir);
137
138/// Entries returned by the [`ReadDir`] iterator.
139///
140/// An instance of `DirEntry` represents an entry inside of a directory on the
141/// filesystem. Each entry can be inspected via methods to learn about the full
142/// path or possibly other metadata through per-platform extension traits.
143///
144/// # Platform-specific behavior
145///
146/// On Unix, the `DirEntry` struct contains an internal reference to the open
147/// directory. Holding `DirEntry` objects will consume a file handle even
148/// after the `ReadDir` iterator is dropped.
149///
150/// Note that this [may change in the future][changes].
151///
152/// [changes]: io#platform-specific-behavior
153#[stable(feature = "rust1", since = "1.0.0")]
154pub struct DirEntry(fs_imp::DirEntry);
155
156/// Options and flags which can be used to configure how a file is opened.
157///
158/// This builder exposes the ability to configure how a [`File`] is opened and
159/// what operations are permitted on the open file. The [`File::open`] and
160/// [`File::create`] methods are aliases for commonly used options using this
161/// builder.
162///
163/// Generally speaking, when using `OpenOptions`, you'll first call
164/// [`OpenOptions::new`], then chain calls to methods to set each option, then
165/// call [`OpenOptions::open`], passing the path of the file you're trying to
166/// open. This will give you a [`io::Result`] with a [`File`] inside that you
167/// can further operate on.
168///
169/// # Examples
170///
171/// Opening a file to read:
172///
173/// ```no_run
174/// use std::fs::OpenOptions;
175///
176/// let file = OpenOptions::new().read(true).open("foo.txt");
177/// ```
178///
179/// Opening a file for both reading and writing, as well as creating it if it
180/// doesn't exist:
181///
182/// ```no_run
183/// use std::fs::OpenOptions;
184///
185/// let file = OpenOptions::new()
186/// .read(true)
187/// .write(true)
188/// .create(true)
189/// .open("foo.txt");
190/// ```
191#[derive(Clone, Debug)]
192#[stable(feature = "rust1", since = "1.0.0")]
193#[cfg_attr(not(test), rustc_diagnostic_item = "FsOpenOptions")]
194pub struct OpenOptions(fs_imp::OpenOptions);
195
196/// Representation of the various timestamps on a file.
197#[derive(Copy, Clone, Debug, Default)]
198#[stable(feature = "file_set_times", since = "1.75.0")]
199pub struct FileTimes(fs_imp::FileTimes);
200
201/// Representation of the various permissions on a file.
202///
203/// This module only currently provides one bit of information,
204/// [`Permissions::readonly`], which is exposed on all currently supported
205/// platforms. Unix-specific functionality, such as mode bits, is available
206/// through the [`PermissionsExt`] trait.
207///
208/// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
209#[derive(Clone, PartialEq, Eq, Debug)]
210#[stable(feature = "rust1", since = "1.0.0")]
211#[cfg_attr(not(test), rustc_diagnostic_item = "FsPermissions")]
212pub struct Permissions(fs_imp::FilePermissions);
213
214/// A structure representing a type of file with accessors for each file type.
215/// It is returned by [`Metadata::file_type`] method.
216#[stable(feature = "file_type", since = "1.1.0")]
217#[derive(Copy, Clone, PartialEq, Eq, Hash, Debug)]
218#[cfg_attr(not(test), rustc_diagnostic_item = "FileType")]
219pub struct FileType(fs_imp::FileType);
220
221/// A builder used to create directories in various manners.
222///
223/// This builder also supports platform-specific options.
224#[stable(feature = "dir_builder", since = "1.6.0")]
225#[cfg_attr(not(test), rustc_diagnostic_item = "DirBuilder")]
226#[derive(Debug)]
227pub struct DirBuilder {
228 inner: fs_imp::DirBuilder,
229 recursive: bool,
230}
231
232/// Read the entire contents of a file into a bytes vector.
233///
234/// This is a convenience function for using [`File::open`] and [`read_to_end`]
235/// with fewer imports and without an intermediate variable.
236///
237/// [`read_to_end`]: Read::read_to_end
238///
239/// # Errors
240///
241/// This function will return an error if `path` does not already exist.
242/// Other errors may also be returned according to [`OpenOptions::open`].
243///
244/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
245/// with automatic retries. See [io::Read] documentation for details.
246///
247/// # Examples
248///
249/// ```no_run
250/// use std::fs;
251/// use std::net::SocketAddr;
252///
253/// fn main() -> Result<(), Box<dyn std::error::Error + 'static>> {
254/// let foo: SocketAddr = String::from_utf8_lossy(&fs::read("address.txt")?).parse()?;
255/// Ok(())
256/// }
257/// ```
258#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
259pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
260 fn inner(path: &Path) -> io::Result<Vec<u8>> {
261 let mut file: File = File::open(path)?;
262 let size: Option = file.metadata().map(|m: Metadata| m.len() as usize).ok();
263 let mut bytes: Vec = Vec::new();
264 bytes.try_reserve_exact(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
265 io::default_read_to_end(&mut file, &mut bytes, size_hint:size)?;
266 Ok(bytes)
267 }
268 inner(path.as_ref())
269}
270
271/// Read the entire contents of a file into a string.
272///
273/// This is a convenience function for using [`File::open`] and [`read_to_string`]
274/// with fewer imports and without an intermediate variable.
275///
276/// [`read_to_string`]: Read::read_to_string
277///
278/// # Errors
279///
280/// This function will return an error if `path` does not already exist.
281/// Other errors may also be returned according to [`OpenOptions::open`].
282///
283/// If the contents of the file are not valid UTF-8, then an error will also be
284/// returned.
285///
286/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
287/// with automatic retries. See [io::Read] documentation for details.
288///
289/// # Examples
290///
291/// ```no_run
292/// use std::fs;
293/// use std::net::SocketAddr;
294/// use std::error::Error;
295///
296/// fn main() -> Result<(), Box<dyn Error>> {
297/// let foo: SocketAddr = fs::read_to_string("address.txt")?.parse()?;
298/// Ok(())
299/// }
300/// ```
301#[stable(feature = "fs_read_write", since = "1.26.0")]
302pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
303 fn inner(path: &Path) -> io::Result<String> {
304 let mut file: File = File::open(path)?;
305 let size: Option = file.metadata().map(|m: Metadata| m.len() as usize).ok();
306 let mut string: String = String::new();
307 string.try_reserve_exact(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
308 io::default_read_to_string(&mut file, &mut string, size_hint:size)?;
309 Ok(string)
310 }
311 inner(path.as_ref())
312}
313
314/// Write a slice as the entire contents of a file.
315///
316/// This function will create a file if it does not exist,
317/// and will entirely replace its contents if it does.
318///
319/// Depending on the platform, this function may fail if the
320/// full directory path does not exist.
321///
322/// This is a convenience function for using [`File::create`] and [`write_all`]
323/// with fewer imports.
324///
325/// [`write_all`]: Write::write_all
326///
327/// # Examples
328///
329/// ```no_run
330/// use std::fs;
331///
332/// fn main() -> std::io::Result<()> {
333/// fs::write("foo.txt", b"Lorem ipsum")?;
334/// fs::write("bar.txt", "dolor sit")?;
335/// Ok(())
336/// }
337/// ```
338#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
339pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> io::Result<()> {
340 fn inner(path: &Path, contents: &[u8]) -> io::Result<()> {
341 File::create(path)?.write_all(buf:contents)
342 }
343 inner(path.as_ref(), contents.as_ref())
344}
345
346impl File {
347 /// Attempts to open a file in read-only mode.
348 ///
349 /// See the [`OpenOptions::open`] method for more details.
350 ///
351 /// If you only need to read the entire file contents,
352 /// consider [`std::fs::read()`][self::read] or
353 /// [`std::fs::read_to_string()`][self::read_to_string] instead.
354 ///
355 /// # Errors
356 ///
357 /// This function will return an error if `path` does not already exist.
358 /// Other errors may also be returned according to [`OpenOptions::open`].
359 ///
360 /// # Examples
361 ///
362 /// ```no_run
363 /// use std::fs::File;
364 /// use std::io::Read;
365 ///
366 /// fn main() -> std::io::Result<()> {
367 /// let mut f = File::open("foo.txt")?;
368 /// let mut data = vec![];
369 /// f.read_to_end(&mut data)?;
370 /// Ok(())
371 /// }
372 /// ```
373 #[stable(feature = "rust1", since = "1.0.0")]
374 pub fn open<P: AsRef<Path>>(path: P) -> io::Result<File> {
375 OpenOptions::new().read(true).open(path.as_ref())
376 }
377
378 /// Opens a file in write-only mode.
379 ///
380 /// This function will create a file if it does not exist,
381 /// and will truncate it if it does.
382 ///
383 /// Depending on the platform, this function may fail if the
384 /// full directory path does not exist.
385 /// See the [`OpenOptions::open`] function for more details.
386 ///
387 /// See also [`std::fs::write()`][self::write] for a simple function to
388 /// create a file with a given data.
389 ///
390 /// # Examples
391 ///
392 /// ```no_run
393 /// use std::fs::File;
394 /// use std::io::Write;
395 ///
396 /// fn main() -> std::io::Result<()> {
397 /// let mut f = File::create("foo.txt")?;
398 /// f.write_all(&1234_u32.to_be_bytes())?;
399 /// Ok(())
400 /// }
401 /// ```
402 #[stable(feature = "rust1", since = "1.0.0")]
403 pub fn create<P: AsRef<Path>>(path: P) -> io::Result<File> {
404 OpenOptions::new().write(true).create(true).truncate(true).open(path.as_ref())
405 }
406
407 /// Creates a new file in read-write mode; error if the file exists.
408 ///
409 /// This function will create a file if it does not exist, or return an error if it does. This
410 /// way, if the call succeeds, the file returned is guaranteed to be new.
411 ///
412 /// This option is useful because it is atomic. Otherwise between checking whether a file
413 /// exists and creating a new one, the file may have been created by another process (a TOCTOU
414 /// race condition / attack).
415 ///
416 /// This can also be written using
417 /// `File::options().read(true).write(true).create_new(true).open(...)`.
418 ///
419 /// # Examples
420 ///
421 /// ```no_run
422 /// use std::fs::File;
423 /// use std::io::Write;
424 ///
425 /// fn main() -> std::io::Result<()> {
426 /// let mut f = File::create_new("foo.txt")?;
427 /// f.write_all("Hello, world!".as_bytes())?;
428 /// Ok(())
429 /// }
430 /// ```
431 #[stable(feature = "file_create_new", since = "1.77.0")]
432 pub fn create_new<P: AsRef<Path>>(path: P) -> io::Result<File> {
433 OpenOptions::new().read(true).write(true).create_new(true).open(path.as_ref())
434 }
435
436 /// Returns a new OpenOptions object.
437 ///
438 /// This function returns a new OpenOptions object that you can use to
439 /// open or create a file with specific options if `open()` or `create()`
440 /// are not appropriate.
441 ///
442 /// It is equivalent to `OpenOptions::new()`, but allows you to write more
443 /// readable code. Instead of
444 /// `OpenOptions::new().append(true).open("example.log")`,
445 /// you can write `File::options().append(true).open("example.log")`. This
446 /// also avoids the need to import `OpenOptions`.
447 ///
448 /// See the [`OpenOptions::new`] function for more details.
449 ///
450 /// # Examples
451 ///
452 /// ```no_run
453 /// use std::fs::File;
454 /// use std::io::Write;
455 ///
456 /// fn main() -> std::io::Result<()> {
457 /// let mut f = File::options().append(true).open("example.log")?;
458 /// writeln!(&mut f, "new line")?;
459 /// Ok(())
460 /// }
461 /// ```
462 #[must_use]
463 #[stable(feature = "with_options", since = "1.58.0")]
464 pub fn options() -> OpenOptions {
465 OpenOptions::new()
466 }
467
468 /// Attempts to sync all OS-internal metadata to disk.
469 ///
470 /// This function will attempt to ensure that all in-memory data reaches the
471 /// filesystem before returning.
472 ///
473 /// This can be used to handle errors that would otherwise only be caught
474 /// when the `File` is closed. Dropping a file will ignore errors in
475 /// synchronizing this in-memory data.
476 ///
477 /// # Examples
478 ///
479 /// ```no_run
480 /// use std::fs::File;
481 /// use std::io::prelude::*;
482 ///
483 /// fn main() -> std::io::Result<()> {
484 /// let mut f = File::create("foo.txt")?;
485 /// f.write_all(b"Hello, world!")?;
486 ///
487 /// f.sync_all()?;
488 /// Ok(())
489 /// }
490 /// ```
491 #[stable(feature = "rust1", since = "1.0.0")]
492 pub fn sync_all(&self) -> io::Result<()> {
493 self.inner.fsync()
494 }
495
496 /// This function is similar to [`sync_all`], except that it might not
497 /// synchronize file metadata to the filesystem.
498 ///
499 /// This is intended for use cases that must synchronize content, but don't
500 /// need the metadata on disk. The goal of this method is to reduce disk
501 /// operations.
502 ///
503 /// Note that some platforms may simply implement this in terms of
504 /// [`sync_all`].
505 ///
506 /// [`sync_all`]: File::sync_all
507 ///
508 /// # Examples
509 ///
510 /// ```no_run
511 /// use std::fs::File;
512 /// use std::io::prelude::*;
513 ///
514 /// fn main() -> std::io::Result<()> {
515 /// let mut f = File::create("foo.txt")?;
516 /// f.write_all(b"Hello, world!")?;
517 ///
518 /// f.sync_data()?;
519 /// Ok(())
520 /// }
521 /// ```
522 #[stable(feature = "rust1", since = "1.0.0")]
523 pub fn sync_data(&self) -> io::Result<()> {
524 self.inner.datasync()
525 }
526
527 /// Truncates or extends the underlying file, updating the size of
528 /// this file to become `size`.
529 ///
530 /// If the `size` is less than the current file's size, then the file will
531 /// be shrunk. If it is greater than the current file's size, then the file
532 /// will be extended to `size` and have all of the intermediate data filled
533 /// in with 0s.
534 ///
535 /// The file's cursor isn't changed. In particular, if the cursor was at the
536 /// end and the file is shrunk using this operation, the cursor will now be
537 /// past the end.
538 ///
539 /// # Errors
540 ///
541 /// This function will return an error if the file is not opened for writing.
542 /// Also, [`std::io::ErrorKind::InvalidInput`](crate::io::ErrorKind::InvalidInput)
543 /// will be returned if the desired length would cause an overflow due to
544 /// the implementation specifics.
545 ///
546 /// # Examples
547 ///
548 /// ```no_run
549 /// use std::fs::File;
550 ///
551 /// fn main() -> std::io::Result<()> {
552 /// let mut f = File::create("foo.txt")?;
553 /// f.set_len(10)?;
554 /// Ok(())
555 /// }
556 /// ```
557 ///
558 /// Note that this method alters the content of the underlying file, even
559 /// though it takes `&self` rather than `&mut self`.
560 #[stable(feature = "rust1", since = "1.0.0")]
561 pub fn set_len(&self, size: u64) -> io::Result<()> {
562 self.inner.truncate(size)
563 }
564
565 /// Queries metadata about the underlying file.
566 ///
567 /// # Examples
568 ///
569 /// ```no_run
570 /// use std::fs::File;
571 ///
572 /// fn main() -> std::io::Result<()> {
573 /// let mut f = File::open("foo.txt")?;
574 /// let metadata = f.metadata()?;
575 /// Ok(())
576 /// }
577 /// ```
578 #[stable(feature = "rust1", since = "1.0.0")]
579 pub fn metadata(&self) -> io::Result<Metadata> {
580 self.inner.file_attr().map(Metadata)
581 }
582
583 /// Creates a new `File` instance that shares the same underlying file handle
584 /// as the existing `File` instance. Reads, writes, and seeks will affect
585 /// both `File` instances simultaneously.
586 ///
587 /// # Examples
588 ///
589 /// Creates two handles for a file named `foo.txt`:
590 ///
591 /// ```no_run
592 /// use std::fs::File;
593 ///
594 /// fn main() -> std::io::Result<()> {
595 /// let mut file = File::open("foo.txt")?;
596 /// let file_copy = file.try_clone()?;
597 /// Ok(())
598 /// }
599 /// ```
600 ///
601 /// Assuming there’s a file named `foo.txt` with contents `abcdef\n`, create
602 /// two handles, seek one of them, and read the remaining bytes from the
603 /// other handle:
604 ///
605 /// ```no_run
606 /// use std::fs::File;
607 /// use std::io::SeekFrom;
608 /// use std::io::prelude::*;
609 ///
610 /// fn main() -> std::io::Result<()> {
611 /// let mut file = File::open("foo.txt")?;
612 /// let mut file_copy = file.try_clone()?;
613 ///
614 /// file.seek(SeekFrom::Start(3))?;
615 ///
616 /// let mut contents = vec![];
617 /// file_copy.read_to_end(&mut contents)?;
618 /// assert_eq!(contents, b"def\n");
619 /// Ok(())
620 /// }
621 /// ```
622 #[stable(feature = "file_try_clone", since = "1.9.0")]
623 pub fn try_clone(&self) -> io::Result<File> {
624 Ok(File { inner: self.inner.duplicate()? })
625 }
626
627 /// Changes the permissions on the underlying file.
628 ///
629 /// # Platform-specific behavior
630 ///
631 /// This function currently corresponds to the `fchmod` function on Unix and
632 /// the `SetFileInformationByHandle` function on Windows. Note that, this
633 /// [may change in the future][changes].
634 ///
635 /// [changes]: io#platform-specific-behavior
636 ///
637 /// # Errors
638 ///
639 /// This function will return an error if the user lacks permission change
640 /// attributes on the underlying file. It may also return an error in other
641 /// os-specific unspecified cases.
642 ///
643 /// # Examples
644 ///
645 /// ```no_run
646 /// fn main() -> std::io::Result<()> {
647 /// use std::fs::File;
648 ///
649 /// let file = File::open("foo.txt")?;
650 /// let mut perms = file.metadata()?.permissions();
651 /// perms.set_readonly(true);
652 /// file.set_permissions(perms)?;
653 /// Ok(())
654 /// }
655 /// ```
656 ///
657 /// Note that this method alters the permissions of the underlying file,
658 /// even though it takes `&self` rather than `&mut self`.
659 #[stable(feature = "set_permissions_atomic", since = "1.16.0")]
660 pub fn set_permissions(&self, perm: Permissions) -> io::Result<()> {
661 self.inner.set_permissions(perm.0)
662 }
663
664 /// Changes the timestamps of the underlying file.
665 ///
666 /// # Platform-specific behavior
667 ///
668 /// This function currently corresponds to the `futimens` function on Unix (falling back to
669 /// `futimes` on macOS before 10.13) and the `SetFileTime` function on Windows. Note that this
670 /// [may change in the future][changes].
671 ///
672 /// [changes]: io#platform-specific-behavior
673 ///
674 /// # Errors
675 ///
676 /// This function will return an error if the user lacks permission to change timestamps on the
677 /// underlying file. It may also return an error in other os-specific unspecified cases.
678 ///
679 /// This function may return an error if the operating system lacks support to change one or
680 /// more of the timestamps set in the `FileTimes` structure.
681 ///
682 /// # Examples
683 ///
684 /// ```no_run
685 /// fn main() -> std::io::Result<()> {
686 /// use std::fs::{self, File, FileTimes};
687 ///
688 /// let src = fs::metadata("src")?;
689 /// let dest = File::options().write(true).open("dest")?;
690 /// let times = FileTimes::new()
691 /// .set_accessed(src.accessed()?)
692 /// .set_modified(src.modified()?);
693 /// dest.set_times(times)?;
694 /// Ok(())
695 /// }
696 /// ```
697 #[stable(feature = "file_set_times", since = "1.75.0")]
698 #[doc(alias = "futimens")]
699 #[doc(alias = "futimes")]
700 #[doc(alias = "SetFileTime")]
701 pub fn set_times(&self, times: FileTimes) -> io::Result<()> {
702 self.inner.set_times(times.0)
703 }
704
705 /// Changes the modification time of the underlying file.
706 ///
707 /// This is an alias for `set_times(FileTimes::new().set_modified(time))`.
708 #[stable(feature = "file_set_times", since = "1.75.0")]
709 #[inline]
710 pub fn set_modified(&self, time: SystemTime) -> io::Result<()> {
711 self.set_times(FileTimes::new().set_modified(time))
712 }
713}
714
715// In addition to the `impl`s here, `File` also has `impl`s for
716// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
717// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
718// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
719// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
720
721impl AsInner<fs_imp::File> for File {
722 #[inline]
723 fn as_inner(&self) -> &fs_imp::File {
724 &self.inner
725 }
726}
727impl FromInner<fs_imp::File> for File {
728 fn from_inner(f: fs_imp::File) -> File {
729 File { inner: f }
730 }
731}
732impl IntoInner<fs_imp::File> for File {
733 fn into_inner(self) -> fs_imp::File {
734 self.inner
735 }
736}
737
738#[stable(feature = "rust1", since = "1.0.0")]
739impl fmt::Debug for File {
740 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
741 self.inner.fmt(f)
742 }
743}
744
745/// Indicates how much extra capacity is needed to read the rest of the file.
746fn buffer_capacity_required(mut file: &File) -> Option<usize> {
747 let size: u64 = file.metadata().map(|m: Metadata| m.len()).ok()?;
748 let pos: u64 = file.stream_position().ok()?;
749 // Don't worry about `usize` overflow because reading will fail regardless
750 // in that case.
751 Some(size.saturating_sub(pos) as usize)
752}
753
754#[stable(feature = "rust1", since = "1.0.0")]
755impl Read for &File {
756 #[inline]
757 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
758 self.inner.read(buf)
759 }
760
761 #[inline]
762 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
763 self.inner.read_vectored(bufs)
764 }
765
766 #[inline]
767 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
768 self.inner.read_buf(cursor)
769 }
770
771 #[inline]
772 fn is_read_vectored(&self) -> bool {
773 self.inner.is_read_vectored()
774 }
775
776 // Reserves space in the buffer based on the file size when available.
777 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
778 let size = buffer_capacity_required(self);
779 buf.try_reserve_exact(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
780 io::default_read_to_end(self, buf, size)
781 }
782
783 // Reserves space in the buffer based on the file size when available.
784 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
785 let size = buffer_capacity_required(self);
786 buf.try_reserve_exact(size.unwrap_or(0)).map_err(|_| io::ErrorKind::OutOfMemory)?;
787 io::default_read_to_string(self, buf, size)
788 }
789}
790#[stable(feature = "rust1", since = "1.0.0")]
791impl Write for &File {
792 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
793 self.inner.write(buf)
794 }
795
796 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
797 self.inner.write_vectored(bufs)
798 }
799
800 #[inline]
801 fn is_write_vectored(&self) -> bool {
802 self.inner.is_write_vectored()
803 }
804
805 #[inline]
806 fn flush(&mut self) -> io::Result<()> {
807 self.inner.flush()
808 }
809}
810#[stable(feature = "rust1", since = "1.0.0")]
811impl Seek for &File {
812 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
813 self.inner.seek(pos)
814 }
815}
816
817#[stable(feature = "rust1", since = "1.0.0")]
818impl Read for File {
819 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
820 (&*self).read(buf)
821 }
822 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
823 (&*self).read_vectored(bufs)
824 }
825 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
826 (&*self).read_buf(cursor)
827 }
828 #[inline]
829 fn is_read_vectored(&self) -> bool {
830 (&&*self).is_read_vectored()
831 }
832 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
833 (&*self).read_to_end(buf)
834 }
835 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
836 (&*self).read_to_string(buf)
837 }
838}
839#[stable(feature = "rust1", since = "1.0.0")]
840impl Write for File {
841 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
842 (&*self).write(buf)
843 }
844 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
845 (&*self).write_vectored(bufs)
846 }
847 #[inline]
848 fn is_write_vectored(&self) -> bool {
849 (&&*self).is_write_vectored()
850 }
851 #[inline]
852 fn flush(&mut self) -> io::Result<()> {
853 (&*self).flush()
854 }
855}
856#[stable(feature = "rust1", since = "1.0.0")]
857impl Seek for File {
858 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
859 (&*self).seek(pos)
860 }
861}
862
863#[stable(feature = "io_traits_arc", since = "1.73.0")]
864impl Read for Arc<File> {
865 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
866 (&**self).read(buf)
867 }
868 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
869 (&**self).read_vectored(bufs)
870 }
871 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
872 (&**self).read_buf(cursor)
873 }
874 #[inline]
875 fn is_read_vectored(&self) -> bool {
876 (&**self).is_read_vectored()
877 }
878 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
879 (&**self).read_to_end(buf)
880 }
881 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
882 (&**self).read_to_string(buf)
883 }
884}
885#[stable(feature = "io_traits_arc", since = "1.73.0")]
886impl Write for Arc<File> {
887 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
888 (&**self).write(buf)
889 }
890 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
891 (&**self).write_vectored(bufs)
892 }
893 #[inline]
894 fn is_write_vectored(&self) -> bool {
895 (&**self).is_write_vectored()
896 }
897 #[inline]
898 fn flush(&mut self) -> io::Result<()> {
899 (&**self).flush()
900 }
901}
902#[stable(feature = "io_traits_arc", since = "1.73.0")]
903impl Seek for Arc<File> {
904 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
905 (&**self).seek(pos)
906 }
907}
908
909impl OpenOptions {
910 /// Creates a blank new set of options ready for configuration.
911 ///
912 /// All options are initially set to `false`.
913 ///
914 /// # Examples
915 ///
916 /// ```no_run
917 /// use std::fs::OpenOptions;
918 ///
919 /// let mut options = OpenOptions::new();
920 /// let file = options.read(true).open("foo.txt");
921 /// ```
922 #[stable(feature = "rust1", since = "1.0.0")]
923 #[must_use]
924 pub fn new() -> Self {
925 OpenOptions(fs_imp::OpenOptions::new())
926 }
927
928 /// Sets the option for read access.
929 ///
930 /// This option, when true, will indicate that the file should be
931 /// `read`-able if opened.
932 ///
933 /// # Examples
934 ///
935 /// ```no_run
936 /// use std::fs::OpenOptions;
937 ///
938 /// let file = OpenOptions::new().read(true).open("foo.txt");
939 /// ```
940 #[stable(feature = "rust1", since = "1.0.0")]
941 pub fn read(&mut self, read: bool) -> &mut Self {
942 self.0.read(read);
943 self
944 }
945
946 /// Sets the option for write access.
947 ///
948 /// This option, when true, will indicate that the file should be
949 /// `write`-able if opened.
950 ///
951 /// If the file already exists, any write calls on it will overwrite its
952 /// contents, without truncating it.
953 ///
954 /// # Examples
955 ///
956 /// ```no_run
957 /// use std::fs::OpenOptions;
958 ///
959 /// let file = OpenOptions::new().write(true).open("foo.txt");
960 /// ```
961 #[stable(feature = "rust1", since = "1.0.0")]
962 pub fn write(&mut self, write: bool) -> &mut Self {
963 self.0.write(write);
964 self
965 }
966
967 /// Sets the option for the append mode.
968 ///
969 /// This option, when true, means that writes will append to a file instead
970 /// of overwriting previous contents.
971 /// Note that setting `.write(true).append(true)` has the same effect as
972 /// setting only `.append(true)`.
973 ///
974 /// For most filesystems, the operating system guarantees that all writes are
975 /// atomic: no writes get mangled because another process writes at the same
976 /// time.
977 ///
978 /// One maybe obvious note when using append-mode: make sure that all data
979 /// that belongs together is written to the file in one operation. This
980 /// can be done by concatenating strings before passing them to [`write()`],
981 /// or using a buffered writer (with a buffer of adequate size),
982 /// and calling [`flush()`] when the message is complete.
983 ///
984 /// If a file is opened with both read and append access, beware that after
985 /// opening, and after every write, the position for reading may be set at the
986 /// end of the file. So, before writing, save the current position (using
987 /// <code>[seek]\([SeekFrom]::[Current]\(0))</code>), and restore it before the next read.
988 ///
989 /// ## Note
990 ///
991 /// This function doesn't create the file if it doesn't exist. Use the
992 /// [`OpenOptions::create`] method to do so.
993 ///
994 /// [`write()`]: Write::write "io::Write::write"
995 /// [`flush()`]: Write::flush "io::Write::flush"
996 /// [seek]: Seek::seek "io::Seek::seek"
997 /// [Current]: SeekFrom::Current "io::SeekFrom::Current"
998 ///
999 /// # Examples
1000 ///
1001 /// ```no_run
1002 /// use std::fs::OpenOptions;
1003 ///
1004 /// let file = OpenOptions::new().append(true).open("foo.txt");
1005 /// ```
1006 #[stable(feature = "rust1", since = "1.0.0")]
1007 pub fn append(&mut self, append: bool) -> &mut Self {
1008 self.0.append(append);
1009 self
1010 }
1011
1012 /// Sets the option for truncating a previous file.
1013 ///
1014 /// If a file is successfully opened with this option set it will truncate
1015 /// the file to 0 length if it already exists.
1016 ///
1017 /// The file must be opened with write access for truncate to work.
1018 ///
1019 /// # Examples
1020 ///
1021 /// ```no_run
1022 /// use std::fs::OpenOptions;
1023 ///
1024 /// let file = OpenOptions::new().write(true).truncate(true).open("foo.txt");
1025 /// ```
1026 #[stable(feature = "rust1", since = "1.0.0")]
1027 pub fn truncate(&mut self, truncate: bool) -> &mut Self {
1028 self.0.truncate(truncate);
1029 self
1030 }
1031
1032 /// Sets the option to create a new file, or open it if it already exists.
1033 ///
1034 /// In order for the file to be created, [`OpenOptions::write`] or
1035 /// [`OpenOptions::append`] access must be used.
1036 ///
1037 /// See also [`std::fs::write()`][self::write] for a simple function to
1038 /// create a file with a given data.
1039 ///
1040 /// # Examples
1041 ///
1042 /// ```no_run
1043 /// use std::fs::OpenOptions;
1044 ///
1045 /// let file = OpenOptions::new().write(true).create(true).open("foo.txt");
1046 /// ```
1047 #[stable(feature = "rust1", since = "1.0.0")]
1048 pub fn create(&mut self, create: bool) -> &mut Self {
1049 self.0.create(create);
1050 self
1051 }
1052
1053 /// Sets the option to create a new file, failing if it already exists.
1054 ///
1055 /// No file is allowed to exist at the target location, also no (dangling) symlink. In this
1056 /// way, if the call succeeds, the file returned is guaranteed to be new.
1057 ///
1058 /// This option is useful because it is atomic. Otherwise between checking
1059 /// whether a file exists and creating a new one, the file may have been
1060 /// created by another process (a TOCTOU race condition / attack).
1061 ///
1062 /// If `.create_new(true)` is set, [`.create()`] and [`.truncate()`] are
1063 /// ignored.
1064 ///
1065 /// The file must be opened with write or append access in order to create
1066 /// a new file.
1067 ///
1068 /// [`.create()`]: OpenOptions::create
1069 /// [`.truncate()`]: OpenOptions::truncate
1070 ///
1071 /// # Examples
1072 ///
1073 /// ```no_run
1074 /// use std::fs::OpenOptions;
1075 ///
1076 /// let file = OpenOptions::new().write(true)
1077 /// .create_new(true)
1078 /// .open("foo.txt");
1079 /// ```
1080 #[stable(feature = "expand_open_options2", since = "1.9.0")]
1081 pub fn create_new(&mut self, create_new: bool) -> &mut Self {
1082 self.0.create_new(create_new);
1083 self
1084 }
1085
1086 /// Opens a file at `path` with the options specified by `self`.
1087 ///
1088 /// # Errors
1089 ///
1090 /// This function will return an error under a number of different
1091 /// circumstances. Some of these error conditions are listed here, together
1092 /// with their [`io::ErrorKind`]. The mapping to [`io::ErrorKind`]s is not
1093 /// part of the compatibility contract of the function.
1094 ///
1095 /// * [`NotFound`]: The specified file does not exist and neither `create`
1096 /// or `create_new` is set.
1097 /// * [`NotFound`]: One of the directory components of the file path does
1098 /// not exist.
1099 /// * [`PermissionDenied`]: The user lacks permission to get the specified
1100 /// access rights for the file.
1101 /// * [`PermissionDenied`]: The user lacks permission to open one of the
1102 /// directory components of the specified path.
1103 /// * [`AlreadyExists`]: `create_new` was specified and the file already
1104 /// exists.
1105 /// * [`InvalidInput`]: Invalid combinations of open options (truncate
1106 /// without write access, no access mode set, etc.).
1107 ///
1108 /// The following errors don't match any existing [`io::ErrorKind`] at the moment:
1109 /// * One of the directory components of the specified file path
1110 /// was not, in fact, a directory.
1111 /// * Filesystem-level errors: full disk, write permission
1112 /// requested on a read-only file system, exceeded disk quota, too many
1113 /// open files, too long filename, too many symbolic links in the
1114 /// specified path (Unix-like systems only), etc.
1115 ///
1116 /// # Examples
1117 ///
1118 /// ```no_run
1119 /// use std::fs::OpenOptions;
1120 ///
1121 /// let file = OpenOptions::new().read(true).open("foo.txt");
1122 /// ```
1123 ///
1124 /// [`AlreadyExists`]: io::ErrorKind::AlreadyExists
1125 /// [`InvalidInput`]: io::ErrorKind::InvalidInput
1126 /// [`NotFound`]: io::ErrorKind::NotFound
1127 /// [`PermissionDenied`]: io::ErrorKind::PermissionDenied
1128 #[stable(feature = "rust1", since = "1.0.0")]
1129 pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
1130 self._open(path.as_ref())
1131 }
1132
1133 fn _open(&self, path: &Path) -> io::Result<File> {
1134 fs_imp::File::open(path, &self.0).map(|inner| File { inner })
1135 }
1136}
1137
1138impl AsInner<fs_imp::OpenOptions> for OpenOptions {
1139 #[inline]
1140 fn as_inner(&self) -> &fs_imp::OpenOptions {
1141 &self.0
1142 }
1143}
1144
1145impl AsInnerMut<fs_imp::OpenOptions> for OpenOptions {
1146 #[inline]
1147 fn as_inner_mut(&mut self) -> &mut fs_imp::OpenOptions {
1148 &mut self.0
1149 }
1150}
1151
1152impl Metadata {
1153 /// Returns the file type for this metadata.
1154 ///
1155 /// # Examples
1156 ///
1157 /// ```no_run
1158 /// fn main() -> std::io::Result<()> {
1159 /// use std::fs;
1160 ///
1161 /// let metadata = fs::metadata("foo.txt")?;
1162 ///
1163 /// println!("{:?}", metadata.file_type());
1164 /// Ok(())
1165 /// }
1166 /// ```
1167 #[must_use]
1168 #[stable(feature = "file_type", since = "1.1.0")]
1169 pub fn file_type(&self) -> FileType {
1170 FileType(self.0.file_type())
1171 }
1172
1173 /// Returns `true` if this metadata is for a directory. The
1174 /// result is mutually exclusive to the result of
1175 /// [`Metadata::is_file`], and will be false for symlink metadata
1176 /// obtained from [`symlink_metadata`].
1177 ///
1178 /// # Examples
1179 ///
1180 /// ```no_run
1181 /// fn main() -> std::io::Result<()> {
1182 /// use std::fs;
1183 ///
1184 /// let metadata = fs::metadata("foo.txt")?;
1185 ///
1186 /// assert!(!metadata.is_dir());
1187 /// Ok(())
1188 /// }
1189 /// ```
1190 #[must_use]
1191 #[stable(feature = "rust1", since = "1.0.0")]
1192 pub fn is_dir(&self) -> bool {
1193 self.file_type().is_dir()
1194 }
1195
1196 /// Returns `true` if this metadata is for a regular file. The
1197 /// result is mutually exclusive to the result of
1198 /// [`Metadata::is_dir`], and will be false for symlink metadata
1199 /// obtained from [`symlink_metadata`].
1200 ///
1201 /// When the goal is simply to read from (or write to) the source, the most
1202 /// reliable way to test the source can be read (or written to) is to open
1203 /// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
1204 /// a Unix-like system for example. See [`File::open`] or
1205 /// [`OpenOptions::open`] for more information.
1206 ///
1207 /// # Examples
1208 ///
1209 /// ```no_run
1210 /// use std::fs;
1211 ///
1212 /// fn main() -> std::io::Result<()> {
1213 /// let metadata = fs::metadata("foo.txt")?;
1214 ///
1215 /// assert!(metadata.is_file());
1216 /// Ok(())
1217 /// }
1218 /// ```
1219 #[must_use]
1220 #[stable(feature = "rust1", since = "1.0.0")]
1221 pub fn is_file(&self) -> bool {
1222 self.file_type().is_file()
1223 }
1224
1225 /// Returns `true` if this metadata is for a symbolic link.
1226 ///
1227 /// # Examples
1228 ///
1229 #[cfg_attr(unix, doc = "```no_run")]
1230 #[cfg_attr(not(unix), doc = "```ignore")]
1231 /// use std::fs;
1232 /// use std::path::Path;
1233 /// use std::os::unix::fs::symlink;
1234 ///
1235 /// fn main() -> std::io::Result<()> {
1236 /// let link_path = Path::new("link");
1237 /// symlink("/origin_does_not_exist/", link_path)?;
1238 ///
1239 /// let metadata = fs::symlink_metadata(link_path)?;
1240 ///
1241 /// assert!(metadata.is_symlink());
1242 /// Ok(())
1243 /// }
1244 /// ```
1245 #[must_use]
1246 #[stable(feature = "is_symlink", since = "1.58.0")]
1247 pub fn is_symlink(&self) -> bool {
1248 self.file_type().is_symlink()
1249 }
1250
1251 /// Returns the size of the file, in bytes, this metadata is for.
1252 ///
1253 /// # Examples
1254 ///
1255 /// ```no_run
1256 /// use std::fs;
1257 ///
1258 /// fn main() -> std::io::Result<()> {
1259 /// let metadata = fs::metadata("foo.txt")?;
1260 ///
1261 /// assert_eq!(0, metadata.len());
1262 /// Ok(())
1263 /// }
1264 /// ```
1265 #[must_use]
1266 #[stable(feature = "rust1", since = "1.0.0")]
1267 pub fn len(&self) -> u64 {
1268 self.0.size()
1269 }
1270
1271 /// Returns the permissions of the file this metadata is for.
1272 ///
1273 /// # Examples
1274 ///
1275 /// ```no_run
1276 /// use std::fs;
1277 ///
1278 /// fn main() -> std::io::Result<()> {
1279 /// let metadata = fs::metadata("foo.txt")?;
1280 ///
1281 /// assert!(!metadata.permissions().readonly());
1282 /// Ok(())
1283 /// }
1284 /// ```
1285 #[must_use]
1286 #[stable(feature = "rust1", since = "1.0.0")]
1287 pub fn permissions(&self) -> Permissions {
1288 Permissions(self.0.perm())
1289 }
1290
1291 /// Returns the last modification time listed in this metadata.
1292 ///
1293 /// The returned value corresponds to the `mtime` field of `stat` on Unix
1294 /// platforms and the `ftLastWriteTime` field on Windows platforms.
1295 ///
1296 /// # Errors
1297 ///
1298 /// This field might not be available on all platforms, and will return an
1299 /// `Err` on platforms where it is not available.
1300 ///
1301 /// # Examples
1302 ///
1303 /// ```no_run
1304 /// use std::fs;
1305 ///
1306 /// fn main() -> std::io::Result<()> {
1307 /// let metadata = fs::metadata("foo.txt")?;
1308 ///
1309 /// if let Ok(time) = metadata.modified() {
1310 /// println!("{time:?}");
1311 /// } else {
1312 /// println!("Not supported on this platform");
1313 /// }
1314 /// Ok(())
1315 /// }
1316 /// ```
1317 #[stable(feature = "fs_time", since = "1.10.0")]
1318 pub fn modified(&self) -> io::Result<SystemTime> {
1319 self.0.modified().map(FromInner::from_inner)
1320 }
1321
1322 /// Returns the last access time of this metadata.
1323 ///
1324 /// The returned value corresponds to the `atime` field of `stat` on Unix
1325 /// platforms and the `ftLastAccessTime` field on Windows platforms.
1326 ///
1327 /// Note that not all platforms will keep this field update in a file's
1328 /// metadata, for example Windows has an option to disable updating this
1329 /// time when files are accessed and Linux similarly has `noatime`.
1330 ///
1331 /// # Errors
1332 ///
1333 /// This field might not be available on all platforms, and will return an
1334 /// `Err` on platforms where it is not available.
1335 ///
1336 /// # Examples
1337 ///
1338 /// ```no_run
1339 /// use std::fs;
1340 ///
1341 /// fn main() -> std::io::Result<()> {
1342 /// let metadata = fs::metadata("foo.txt")?;
1343 ///
1344 /// if let Ok(time) = metadata.accessed() {
1345 /// println!("{time:?}");
1346 /// } else {
1347 /// println!("Not supported on this platform");
1348 /// }
1349 /// Ok(())
1350 /// }
1351 /// ```
1352 #[stable(feature = "fs_time", since = "1.10.0")]
1353 pub fn accessed(&self) -> io::Result<SystemTime> {
1354 self.0.accessed().map(FromInner::from_inner)
1355 }
1356
1357 /// Returns the creation time listed in this metadata.
1358 ///
1359 /// The returned value corresponds to the `btime` field of `statx` on
1360 /// Linux kernel starting from to 4.11, the `birthtime` field of `stat` on other
1361 /// Unix platforms, and the `ftCreationTime` field on Windows platforms.
1362 ///
1363 /// # Errors
1364 ///
1365 /// This field might not be available on all platforms, and will return an
1366 /// `Err` on platforms or filesystems where it is not available.
1367 ///
1368 /// # Examples
1369 ///
1370 /// ```no_run
1371 /// use std::fs;
1372 ///
1373 /// fn main() -> std::io::Result<()> {
1374 /// let metadata = fs::metadata("foo.txt")?;
1375 ///
1376 /// if let Ok(time) = metadata.created() {
1377 /// println!("{time:?}");
1378 /// } else {
1379 /// println!("Not supported on this platform or filesystem");
1380 /// }
1381 /// Ok(())
1382 /// }
1383 /// ```
1384 #[stable(feature = "fs_time", since = "1.10.0")]
1385 pub fn created(&self) -> io::Result<SystemTime> {
1386 self.0.created().map(FromInner::from_inner)
1387 }
1388}
1389
1390#[stable(feature = "std_debug", since = "1.16.0")]
1391impl fmt::Debug for Metadata {
1392 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1393 f&mut DebugStruct<'_, '_>.debug_struct("Metadata")
1394 .field("file_type", &self.file_type())
1395 .field("is_dir", &self.is_dir())
1396 .field("is_file", &self.is_file())
1397 .field("permissions", &self.permissions())
1398 .field("modified", &self.modified())
1399 .field("accessed", &self.accessed())
1400 .field(name:"created", &self.created())
1401 .finish_non_exhaustive()
1402 }
1403}
1404
1405impl AsInner<fs_imp::FileAttr> for Metadata {
1406 #[inline]
1407 fn as_inner(&self) -> &fs_imp::FileAttr {
1408 &self.0
1409 }
1410}
1411
1412impl FromInner<fs_imp::FileAttr> for Metadata {
1413 fn from_inner(attr: fs_imp::FileAttr) -> Metadata {
1414 Metadata(attr)
1415 }
1416}
1417
1418impl FileTimes {
1419 /// Create a new `FileTimes` with no times set.
1420 ///
1421 /// Using the resulting `FileTimes` in [`File::set_times`] will not modify any timestamps.
1422 #[stable(feature = "file_set_times", since = "1.75.0")]
1423 pub fn new() -> Self {
1424 Self::default()
1425 }
1426
1427 /// Set the last access time of a file.
1428 #[stable(feature = "file_set_times", since = "1.75.0")]
1429 pub fn set_accessed(mut self, t: SystemTime) -> Self {
1430 self.0.set_accessed(t.into_inner());
1431 self
1432 }
1433
1434 /// Set the last modified time of a file.
1435 #[stable(feature = "file_set_times", since = "1.75.0")]
1436 pub fn set_modified(mut self, t: SystemTime) -> Self {
1437 self.0.set_modified(t.into_inner());
1438 self
1439 }
1440}
1441
1442impl AsInnerMut<fs_imp::FileTimes> for FileTimes {
1443 fn as_inner_mut(&mut self) -> &mut fs_imp::FileTimes {
1444 &mut self.0
1445 }
1446}
1447
1448// For implementing OS extension traits in `std::os`
1449#[stable(feature = "file_set_times", since = "1.75.0")]
1450impl Sealed for FileTimes {}
1451
1452impl Permissions {
1453 /// Returns `true` if these permissions describe a readonly (unwritable) file.
1454 ///
1455 /// # Note
1456 ///
1457 /// This function does not take Access Control Lists (ACLs) or Unix group
1458 /// membership into account.
1459 ///
1460 /// # Windows
1461 ///
1462 /// On Windows this returns [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
1463 /// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
1464 /// but the user may still have permission to change this flag. If
1465 /// `FILE_ATTRIBUTE_READONLY` is *not* set then writes may still fail due
1466 /// to lack of write permission.
1467 /// The behavior of this attribute for directories depends on the Windows
1468 /// version.
1469 ///
1470 /// # Unix (including macOS)
1471 ///
1472 /// On Unix-based platforms this checks if *any* of the owner, group or others
1473 /// write permission bits are set. It does not check if the current
1474 /// user is in the file's assigned group. It also does not check ACLs.
1475 /// Therefore even if this returns true you may not be able to write to the
1476 /// file, and vice versa. The [`PermissionsExt`] trait gives direct access
1477 /// to the permission bits but also does not read ACLs. If you need to
1478 /// accurately know whether or not a file is writable use the `access()`
1479 /// function from libc.
1480 ///
1481 /// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
1482 ///
1483 /// # Examples
1484 ///
1485 /// ```no_run
1486 /// use std::fs::File;
1487 ///
1488 /// fn main() -> std::io::Result<()> {
1489 /// let mut f = File::create("foo.txt")?;
1490 /// let metadata = f.metadata()?;
1491 ///
1492 /// assert_eq!(false, metadata.permissions().readonly());
1493 /// Ok(())
1494 /// }
1495 /// ```
1496 #[must_use = "call `set_readonly` to modify the readonly flag"]
1497 #[stable(feature = "rust1", since = "1.0.0")]
1498 pub fn readonly(&self) -> bool {
1499 self.0.readonly()
1500 }
1501
1502 /// Modifies the readonly flag for this set of permissions. If the
1503 /// `readonly` argument is `true`, using the resulting `Permission` will
1504 /// update file permissions to forbid writing. Conversely, if it's `false`,
1505 /// using the resulting `Permission` will update file permissions to allow
1506 /// writing.
1507 ///
1508 /// This operation does **not** modify the files attributes. This only
1509 /// changes the in-memory value of these attributes for this `Permissions`
1510 /// instance. To modify the files attributes use the [`set_permissions`]
1511 /// function which commits these attribute changes to the file.
1512 ///
1513 /// # Note
1514 ///
1515 /// `set_readonly(false)` makes the file *world-writable* on Unix.
1516 /// You can use the [`PermissionsExt`] trait on Unix to avoid this issue.
1517 ///
1518 /// It also does not take Access Control Lists (ACLs) or Unix group
1519 /// membership into account.
1520 ///
1521 /// # Windows
1522 ///
1523 /// On Windows this sets or clears [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
1524 /// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
1525 /// but the user may still have permission to change this flag. If
1526 /// `FILE_ATTRIBUTE_READONLY` is *not* set then the write may still fail if
1527 /// the user does not have permission to write to the file.
1528 ///
1529 /// In Windows 7 and earlier this attribute prevents deleting empty
1530 /// directories. It does not prevent modifying the directory contents.
1531 /// On later versions of Windows this attribute is ignored for directories.
1532 ///
1533 /// # Unix (including macOS)
1534 ///
1535 /// On Unix-based platforms this sets or clears the write access bit for
1536 /// the owner, group *and* others, equivalent to `chmod a+w <file>`
1537 /// or `chmod a-w <file>` respectively. The latter will grant write access
1538 /// to all users! You can use the [`PermissionsExt`] trait on Unix
1539 /// to avoid this issue.
1540 ///
1541 /// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
1542 ///
1543 /// # Examples
1544 ///
1545 /// ```no_run
1546 /// use std::fs::File;
1547 ///
1548 /// fn main() -> std::io::Result<()> {
1549 /// let f = File::create("foo.txt")?;
1550 /// let metadata = f.metadata()?;
1551 /// let mut permissions = metadata.permissions();
1552 ///
1553 /// permissions.set_readonly(true);
1554 ///
1555 /// // filesystem doesn't change, only the in memory state of the
1556 /// // readonly permission
1557 /// assert_eq!(false, metadata.permissions().readonly());
1558 ///
1559 /// // just this particular `permissions`.
1560 /// assert_eq!(true, permissions.readonly());
1561 /// Ok(())
1562 /// }
1563 /// ```
1564 #[stable(feature = "rust1", since = "1.0.0")]
1565 pub fn set_readonly(&mut self, readonly: bool) {
1566 self.0.set_readonly(readonly)
1567 }
1568}
1569
1570impl FileType {
1571 /// Tests whether this file type represents a directory. The
1572 /// result is mutually exclusive to the results of
1573 /// [`is_file`] and [`is_symlink`]; only zero or one of these
1574 /// tests may pass.
1575 ///
1576 /// [`is_file`]: FileType::is_file
1577 /// [`is_symlink`]: FileType::is_symlink
1578 ///
1579 /// # Examples
1580 ///
1581 /// ```no_run
1582 /// fn main() -> std::io::Result<()> {
1583 /// use std::fs;
1584 ///
1585 /// let metadata = fs::metadata("foo.txt")?;
1586 /// let file_type = metadata.file_type();
1587 ///
1588 /// assert_eq!(file_type.is_dir(), false);
1589 /// Ok(())
1590 /// }
1591 /// ```
1592 #[must_use]
1593 #[stable(feature = "file_type", since = "1.1.0")]
1594 pub fn is_dir(&self) -> bool {
1595 self.0.is_dir()
1596 }
1597
1598 /// Tests whether this file type represents a regular file.
1599 /// The result is mutually exclusive to the results of
1600 /// [`is_dir`] and [`is_symlink`]; only zero or one of these
1601 /// tests may pass.
1602 ///
1603 /// When the goal is simply to read from (or write to) the source, the most
1604 /// reliable way to test the source can be read (or written to) is to open
1605 /// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
1606 /// a Unix-like system for example. See [`File::open`] or
1607 /// [`OpenOptions::open`] for more information.
1608 ///
1609 /// [`is_dir`]: FileType::is_dir
1610 /// [`is_symlink`]: FileType::is_symlink
1611 ///
1612 /// # Examples
1613 ///
1614 /// ```no_run
1615 /// fn main() -> std::io::Result<()> {
1616 /// use std::fs;
1617 ///
1618 /// let metadata = fs::metadata("foo.txt")?;
1619 /// let file_type = metadata.file_type();
1620 ///
1621 /// assert_eq!(file_type.is_file(), true);
1622 /// Ok(())
1623 /// }
1624 /// ```
1625 #[must_use]
1626 #[stable(feature = "file_type", since = "1.1.0")]
1627 pub fn is_file(&self) -> bool {
1628 self.0.is_file()
1629 }
1630
1631 /// Tests whether this file type represents a symbolic link.
1632 /// The result is mutually exclusive to the results of
1633 /// [`is_dir`] and [`is_file`]; only zero or one of these
1634 /// tests may pass.
1635 ///
1636 /// The underlying [`Metadata`] struct needs to be retrieved
1637 /// with the [`fs::symlink_metadata`] function and not the
1638 /// [`fs::metadata`] function. The [`fs::metadata`] function
1639 /// follows symbolic links, so [`is_symlink`] would always
1640 /// return `false` for the target file.
1641 ///
1642 /// [`fs::metadata`]: metadata
1643 /// [`fs::symlink_metadata`]: symlink_metadata
1644 /// [`is_dir`]: FileType::is_dir
1645 /// [`is_file`]: FileType::is_file
1646 /// [`is_symlink`]: FileType::is_symlink
1647 ///
1648 /// # Examples
1649 ///
1650 /// ```no_run
1651 /// use std::fs;
1652 ///
1653 /// fn main() -> std::io::Result<()> {
1654 /// let metadata = fs::symlink_metadata("foo.txt")?;
1655 /// let file_type = metadata.file_type();
1656 ///
1657 /// assert_eq!(file_type.is_symlink(), false);
1658 /// Ok(())
1659 /// }
1660 /// ```
1661 #[must_use]
1662 #[stable(feature = "file_type", since = "1.1.0")]
1663 pub fn is_symlink(&self) -> bool {
1664 self.0.is_symlink()
1665 }
1666}
1667
1668impl AsInner<fs_imp::FileType> for FileType {
1669 #[inline]
1670 fn as_inner(&self) -> &fs_imp::FileType {
1671 &self.0
1672 }
1673}
1674
1675impl FromInner<fs_imp::FilePermissions> for Permissions {
1676 fn from_inner(f: fs_imp::FilePermissions) -> Permissions {
1677 Permissions(f)
1678 }
1679}
1680
1681impl AsInner<fs_imp::FilePermissions> for Permissions {
1682 #[inline]
1683 fn as_inner(&self) -> &fs_imp::FilePermissions {
1684 &self.0
1685 }
1686}
1687
1688#[stable(feature = "rust1", since = "1.0.0")]
1689impl Iterator for ReadDir {
1690 type Item = io::Result<DirEntry>;
1691
1692 fn next(&mut self) -> Option<io::Result<DirEntry>> {
1693 self.0.next().map(|entry: Result| entry.map(op:DirEntry))
1694 }
1695}
1696
1697impl DirEntry {
1698 /// Returns the full path to the file that this entry represents.
1699 ///
1700 /// The full path is created by joining the original path to `read_dir`
1701 /// with the filename of this entry.
1702 ///
1703 /// # Examples
1704 ///
1705 /// ```no_run
1706 /// use std::fs;
1707 ///
1708 /// fn main() -> std::io::Result<()> {
1709 /// for entry in fs::read_dir(".")? {
1710 /// let dir = entry?;
1711 /// println!("{:?}", dir.path());
1712 /// }
1713 /// Ok(())
1714 /// }
1715 /// ```
1716 ///
1717 /// This prints output like:
1718 ///
1719 /// ```text
1720 /// "./whatever.txt"
1721 /// "./foo.html"
1722 /// "./hello_world.rs"
1723 /// ```
1724 ///
1725 /// The exact text, of course, depends on what files you have in `.`.
1726 #[must_use]
1727 #[stable(feature = "rust1", since = "1.0.0")]
1728 pub fn path(&self) -> PathBuf {
1729 self.0.path()
1730 }
1731
1732 /// Returns the metadata for the file that this entry points at.
1733 ///
1734 /// This function will not traverse symlinks if this entry points at a
1735 /// symlink. To traverse symlinks use [`fs::metadata`] or [`fs::File::metadata`].
1736 ///
1737 /// [`fs::metadata`]: metadata
1738 /// [`fs::File::metadata`]: File::metadata
1739 ///
1740 /// # Platform-specific behavior
1741 ///
1742 /// On Windows this function is cheap to call (no extra system calls
1743 /// needed), but on Unix platforms this function is the equivalent of
1744 /// calling `symlink_metadata` on the path.
1745 ///
1746 /// # Examples
1747 ///
1748 /// ```
1749 /// use std::fs;
1750 ///
1751 /// if let Ok(entries) = fs::read_dir(".") {
1752 /// for entry in entries {
1753 /// if let Ok(entry) = entry {
1754 /// // Here, `entry` is a `DirEntry`.
1755 /// if let Ok(metadata) = entry.metadata() {
1756 /// // Now let's show our entry's permissions!
1757 /// println!("{:?}: {:?}", entry.path(), metadata.permissions());
1758 /// } else {
1759 /// println!("Couldn't get metadata for {:?}", entry.path());
1760 /// }
1761 /// }
1762 /// }
1763 /// }
1764 /// ```
1765 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
1766 pub fn metadata(&self) -> io::Result<Metadata> {
1767 self.0.metadata().map(Metadata)
1768 }
1769
1770 /// Returns the file type for the file that this entry points at.
1771 ///
1772 /// This function will not traverse symlinks if this entry points at a
1773 /// symlink.
1774 ///
1775 /// # Platform-specific behavior
1776 ///
1777 /// On Windows and most Unix platforms this function is free (no extra
1778 /// system calls needed), but some Unix platforms may require the equivalent
1779 /// call to `symlink_metadata` to learn about the target file type.
1780 ///
1781 /// # Examples
1782 ///
1783 /// ```
1784 /// use std::fs;
1785 ///
1786 /// if let Ok(entries) = fs::read_dir(".") {
1787 /// for entry in entries {
1788 /// if let Ok(entry) = entry {
1789 /// // Here, `entry` is a `DirEntry`.
1790 /// if let Ok(file_type) = entry.file_type() {
1791 /// // Now let's show our entry's file type!
1792 /// println!("{:?}: {:?}", entry.path(), file_type);
1793 /// } else {
1794 /// println!("Couldn't get file type for {:?}", entry.path());
1795 /// }
1796 /// }
1797 /// }
1798 /// }
1799 /// ```
1800 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
1801 pub fn file_type(&self) -> io::Result<FileType> {
1802 self.0.file_type().map(FileType)
1803 }
1804
1805 /// Returns the file name of this directory entry without any
1806 /// leading path component(s).
1807 ///
1808 /// As an example,
1809 /// the output of the function will result in "foo" for all the following paths:
1810 /// - "./foo"
1811 /// - "/the/foo"
1812 /// - "../../foo"
1813 ///
1814 /// # Examples
1815 ///
1816 /// ```
1817 /// use std::fs;
1818 ///
1819 /// if let Ok(entries) = fs::read_dir(".") {
1820 /// for entry in entries {
1821 /// if let Ok(entry) = entry {
1822 /// // Here, `entry` is a `DirEntry`.
1823 /// println!("{:?}", entry.file_name());
1824 /// }
1825 /// }
1826 /// }
1827 /// ```
1828 #[must_use]
1829 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
1830 pub fn file_name(&self) -> OsString {
1831 self.0.file_name()
1832 }
1833}
1834
1835#[stable(feature = "dir_entry_debug", since = "1.13.0")]
1836impl fmt::Debug for DirEntry {
1837 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1838 f.debug_tuple(name:"DirEntry").field(&self.path()).finish()
1839 }
1840}
1841
1842impl AsInner<fs_imp::DirEntry> for DirEntry {
1843 #[inline]
1844 fn as_inner(&self) -> &fs_imp::DirEntry {
1845 &self.0
1846 }
1847}
1848
1849/// Removes a file from the filesystem.
1850///
1851/// Note that there is no
1852/// guarantee that the file is immediately deleted (e.g., depending on
1853/// platform, other open file descriptors may prevent immediate removal).
1854///
1855/// # Platform-specific behavior
1856///
1857/// This function currently corresponds to the `unlink` function on Unix
1858/// and the `DeleteFile` function on Windows.
1859/// Note that, this [may change in the future][changes].
1860///
1861/// [changes]: io#platform-specific-behavior
1862///
1863/// # Errors
1864///
1865/// This function will return an error in the following situations, but is not
1866/// limited to just these cases:
1867///
1868/// * `path` points to a directory.
1869/// * The file doesn't exist.
1870/// * The user lacks permissions to remove the file.
1871///
1872/// # Examples
1873///
1874/// ```no_run
1875/// use std::fs;
1876///
1877/// fn main() -> std::io::Result<()> {
1878/// fs::remove_file("a.txt")?;
1879/// Ok(())
1880/// }
1881/// ```
1882#[stable(feature = "rust1", since = "1.0.0")]
1883pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
1884 fs_imp::unlink(path.as_ref())
1885}
1886
1887/// Given a path, query the file system to get information about a file,
1888/// directory, etc.
1889///
1890/// This function will traverse symbolic links to query information about the
1891/// destination file.
1892///
1893/// # Platform-specific behavior
1894///
1895/// This function currently corresponds to the `stat` function on Unix
1896/// and the `GetFileInformationByHandle` function on Windows.
1897/// Note that, this [may change in the future][changes].
1898///
1899/// [changes]: io#platform-specific-behavior
1900///
1901/// # Errors
1902///
1903/// This function will return an error in the following situations, but is not
1904/// limited to just these cases:
1905///
1906/// * The user lacks permissions to perform `metadata` call on `path`.
1907/// * `path` does not exist.
1908///
1909/// # Examples
1910///
1911/// ```rust,no_run
1912/// use std::fs;
1913///
1914/// fn main() -> std::io::Result<()> {
1915/// let attr = fs::metadata("/some/file/path.txt")?;
1916/// // inspect attr ...
1917/// Ok(())
1918/// }
1919/// ```
1920#[stable(feature = "rust1", since = "1.0.0")]
1921pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
1922 fs_imp::stat(path.as_ref()).map(op:Metadata)
1923}
1924
1925/// Query the metadata about a file without following symlinks.
1926///
1927/// # Platform-specific behavior
1928///
1929/// This function currently corresponds to the `lstat` function on Unix
1930/// and the `GetFileInformationByHandle` function on Windows.
1931/// Note that, this [may change in the future][changes].
1932///
1933/// [changes]: io#platform-specific-behavior
1934///
1935/// # Errors
1936///
1937/// This function will return an error in the following situations, but is not
1938/// limited to just these cases:
1939///
1940/// * The user lacks permissions to perform `metadata` call on `path`.
1941/// * `path` does not exist.
1942///
1943/// # Examples
1944///
1945/// ```rust,no_run
1946/// use std::fs;
1947///
1948/// fn main() -> std::io::Result<()> {
1949/// let attr = fs::symlink_metadata("/some/file/path.txt")?;
1950/// // inspect attr ...
1951/// Ok(())
1952/// }
1953/// ```
1954#[stable(feature = "symlink_metadata", since = "1.1.0")]
1955pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
1956 fs_imp::lstat(path.as_ref()).map(op:Metadata)
1957}
1958
1959/// Rename a file or directory to a new name, replacing the original file if
1960/// `to` already exists.
1961///
1962/// This will not work if the new name is on a different mount point.
1963///
1964/// # Platform-specific behavior
1965///
1966/// This function currently corresponds to the `rename` function on Unix
1967/// and the `MoveFileEx` function with the `MOVEFILE_REPLACE_EXISTING` flag on Windows.
1968///
1969/// Because of this, the behavior when both `from` and `to` exist differs. On
1970/// Unix, if `from` is a directory, `to` must also be an (empty) directory. If
1971/// `from` is not a directory, `to` must also be not a directory. In contrast,
1972/// on Windows, `from` can be anything, but `to` must *not* be a directory.
1973///
1974/// Note that, this [may change in the future][changes].
1975///
1976/// [changes]: io#platform-specific-behavior
1977///
1978/// # Errors
1979///
1980/// This function will return an error in the following situations, but is not
1981/// limited to just these cases:
1982///
1983/// * `from` does not exist.
1984/// * The user lacks permissions to view contents.
1985/// * `from` and `to` are on separate filesystems.
1986///
1987/// # Examples
1988///
1989/// ```no_run
1990/// use std::fs;
1991///
1992/// fn main() -> std::io::Result<()> {
1993/// fs::rename("a.txt", "b.txt")?; // Rename a.txt to b.txt
1994/// Ok(())
1995/// }
1996/// ```
1997#[stable(feature = "rust1", since = "1.0.0")]
1998pub fn rename<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<()> {
1999 fs_imp::rename(old:from.as_ref(), new:to.as_ref())
2000}
2001
2002/// Copies the contents of one file to another. This function will also
2003/// copy the permission bits of the original file to the destination file.
2004///
2005/// This function will **overwrite** the contents of `to`.
2006///
2007/// Note that if `from` and `to` both point to the same file, then the file
2008/// will likely get truncated by this operation.
2009///
2010/// On success, the total number of bytes copied is returned and it is equal to
2011/// the length of the `to` file as reported by `metadata`.
2012///
2013/// If you want to copy the contents of one file to another and you’re
2014/// working with [`File`]s, see the [`io::copy()`] function.
2015///
2016/// # Platform-specific behavior
2017///
2018/// This function currently corresponds to the `open` function in Unix
2019/// with `O_RDONLY` for `from` and `O_WRONLY`, `O_CREAT`, and `O_TRUNC` for `to`.
2020/// `O_CLOEXEC` is set for returned file descriptors.
2021///
2022/// On Linux (including Android), this function attempts to use `copy_file_range(2)`,
2023/// and falls back to reading and writing if that is not possible.
2024///
2025/// On Windows, this function currently corresponds to `CopyFileEx`. Alternate
2026/// NTFS streams are copied but only the size of the main stream is returned by
2027/// this function.
2028///
2029/// On MacOS, this function corresponds to `fclonefileat` and `fcopyfile`.
2030///
2031/// Note that platform-specific behavior [may change in the future][changes].
2032///
2033/// [changes]: io#platform-specific-behavior
2034///
2035/// # Errors
2036///
2037/// This function will return an error in the following situations, but is not
2038/// limited to just these cases:
2039///
2040/// * `from` is neither a regular file nor a symlink to a regular file.
2041/// * `from` does not exist.
2042/// * The current process does not have the permission rights to read
2043/// `from` or write `to`.
2044///
2045/// # Examples
2046///
2047/// ```no_run
2048/// use std::fs;
2049///
2050/// fn main() -> std::io::Result<()> {
2051/// fs::copy("foo.txt", "bar.txt")?; // Copy foo.txt to bar.txt
2052/// Ok(())
2053/// }
2054/// ```
2055#[stable(feature = "rust1", since = "1.0.0")]
2056pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<u64> {
2057 fs_imp::copy(from.as_ref(), to.as_ref())
2058}
2059
2060/// Creates a new hard link on the filesystem.
2061///
2062/// The `link` path will be a link pointing to the `original` path. Note that
2063/// systems often require these two paths to both be located on the same
2064/// filesystem.
2065///
2066/// If `original` names a symbolic link, it is platform-specific whether the
2067/// symbolic link is followed. On platforms where it's possible to not follow
2068/// it, it is not followed, and the created hard link points to the symbolic
2069/// link itself.
2070///
2071/// # Platform-specific behavior
2072///
2073/// This function currently corresponds the `CreateHardLink` function on Windows.
2074/// On most Unix systems, it corresponds to the `linkat` function with no flags.
2075/// On Android, VxWorks, and Redox, it instead corresponds to the `link` function.
2076/// On MacOS, it uses the `linkat` function if it is available, but on very old
2077/// systems where `linkat` is not available, `link` is selected at runtime instead.
2078/// Note that, this [may change in the future][changes].
2079///
2080/// [changes]: io#platform-specific-behavior
2081///
2082/// # Errors
2083///
2084/// This function will return an error in the following situations, but is not
2085/// limited to just these cases:
2086///
2087/// * The `original` path is not a file or doesn't exist.
2088///
2089/// # Examples
2090///
2091/// ```no_run
2092/// use std::fs;
2093///
2094/// fn main() -> std::io::Result<()> {
2095/// fs::hard_link("a.txt", "b.txt")?; // Hard link a.txt to b.txt
2096/// Ok(())
2097/// }
2098/// ```
2099#[stable(feature = "rust1", since = "1.0.0")]
2100pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
2101 fs_imp::link(original.as_ref(), link.as_ref())
2102}
2103
2104/// Creates a new symbolic link on the filesystem.
2105///
2106/// The `link` path will be a symbolic link pointing to the `original` path.
2107/// On Windows, this will be a file symlink, not a directory symlink;
2108/// for this reason, the platform-specific [`std::os::unix::fs::symlink`]
2109/// and [`std::os::windows::fs::symlink_file`] or [`symlink_dir`] should be
2110/// used instead to make the intent explicit.
2111///
2112/// [`std::os::unix::fs::symlink`]: crate::os::unix::fs::symlink
2113/// [`std::os::windows::fs::symlink_file`]: crate::os::windows::fs::symlink_file
2114/// [`symlink_dir`]: crate::os::windows::fs::symlink_dir
2115///
2116/// # Examples
2117///
2118/// ```no_run
2119/// use std::fs;
2120///
2121/// fn main() -> std::io::Result<()> {
2122/// fs::soft_link("a.txt", "b.txt")?;
2123/// Ok(())
2124/// }
2125/// ```
2126#[stable(feature = "rust1", since = "1.0.0")]
2127#[deprecated(
2128 since = "1.1.0",
2129 note = "replaced with std::os::unix::fs::symlink and \
2130 std::os::windows::fs::{symlink_file, symlink_dir}"
2131)]
2132pub fn soft_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
2133 fs_imp::symlink(original.as_ref(), link.as_ref())
2134}
2135
2136/// Reads a symbolic link, returning the file that the link points to.
2137///
2138/// # Platform-specific behavior
2139///
2140/// This function currently corresponds to the `readlink` function on Unix
2141/// and the `CreateFile` function with `FILE_FLAG_OPEN_REPARSE_POINT` and
2142/// `FILE_FLAG_BACKUP_SEMANTICS` flags on Windows.
2143/// Note that, this [may change in the future][changes].
2144///
2145/// [changes]: io#platform-specific-behavior
2146///
2147/// # Errors
2148///
2149/// This function will return an error in the following situations, but is not
2150/// limited to just these cases:
2151///
2152/// * `path` is not a symbolic link.
2153/// * `path` does not exist.
2154///
2155/// # Examples
2156///
2157/// ```no_run
2158/// use std::fs;
2159///
2160/// fn main() -> std::io::Result<()> {
2161/// let path = fs::read_link("a.txt")?;
2162/// Ok(())
2163/// }
2164/// ```
2165#[stable(feature = "rust1", since = "1.0.0")]
2166pub fn read_link<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
2167 fs_imp::readlink(path.as_ref())
2168}
2169
2170/// Returns the canonical, absolute form of a path with all intermediate
2171/// components normalized and symbolic links resolved.
2172///
2173/// # Platform-specific behavior
2174///
2175/// This function currently corresponds to the `realpath` function on Unix
2176/// and the `CreateFile` and `GetFinalPathNameByHandle` functions on Windows.
2177/// Note that, this [may change in the future][changes].
2178///
2179/// On Windows, this converts the path to use [extended length path][path]
2180/// syntax, which allows your program to use longer path names, but means you
2181/// can only join backslash-delimited paths to it, and it may be incompatible
2182/// with other applications (if passed to the application on the command-line,
2183/// or written to a file another application may read).
2184///
2185/// [changes]: io#platform-specific-behavior
2186/// [path]: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
2187///
2188/// # Errors
2189///
2190/// This function will return an error in the following situations, but is not
2191/// limited to just these cases:
2192///
2193/// * `path` does not exist.
2194/// * A non-final component in path is not a directory.
2195///
2196/// # Examples
2197///
2198/// ```no_run
2199/// use std::fs;
2200///
2201/// fn main() -> std::io::Result<()> {
2202/// let path = fs::canonicalize("../a/../foo.txt")?;
2203/// Ok(())
2204/// }
2205/// ```
2206#[doc(alias = "realpath")]
2207#[doc(alias = "GetFinalPathNameByHandle")]
2208#[stable(feature = "fs_canonicalize", since = "1.5.0")]
2209pub fn canonicalize<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
2210 fs_imp::canonicalize(path.as_ref())
2211}
2212
2213/// Creates a new, empty directory at the provided path
2214///
2215/// # Platform-specific behavior
2216///
2217/// This function currently corresponds to the `mkdir` function on Unix
2218/// and the `CreateDirectory` function on Windows.
2219/// Note that, this [may change in the future][changes].
2220///
2221/// [changes]: io#platform-specific-behavior
2222///
2223/// **NOTE**: If a parent of the given path doesn't exist, this function will
2224/// return an error. To create a directory and all its missing parents at the
2225/// same time, use the [`create_dir_all`] function.
2226///
2227/// # Errors
2228///
2229/// This function will return an error in the following situations, but is not
2230/// limited to just these cases:
2231///
2232/// * User lacks permissions to create directory at `path`.
2233/// * A parent of the given path doesn't exist. (To create a directory and all
2234/// its missing parents at the same time, use the [`create_dir_all`]
2235/// function.)
2236/// * `path` already exists.
2237///
2238/// # Examples
2239///
2240/// ```no_run
2241/// use std::fs;
2242///
2243/// fn main() -> std::io::Result<()> {
2244/// fs::create_dir("/some/dir")?;
2245/// Ok(())
2246/// }
2247/// ```
2248#[doc(alias = "mkdir")]
2249#[stable(feature = "rust1", since = "1.0.0")]
2250#[cfg_attr(not(test), rustc_diagnostic_item = "fs_create_dir")]
2251pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
2252 DirBuilder::new().create(path.as_ref())
2253}
2254
2255/// Recursively create a directory and all of its parent components if they
2256/// are missing.
2257///
2258/// # Platform-specific behavior
2259///
2260/// This function currently corresponds to the `mkdir` function on Unix
2261/// and the `CreateDirectory` function on Windows.
2262/// Note that, this [may change in the future][changes].
2263///
2264/// [changes]: io#platform-specific-behavior
2265///
2266/// # Errors
2267///
2268/// This function will return an error in the following situations, but is not
2269/// limited to just these cases:
2270///
2271/// * If any directory in the path specified by `path`
2272/// does not already exist and it could not be created otherwise. The specific
2273/// error conditions for when a directory is being created (after it is
2274/// determined to not exist) are outlined by [`fs::create_dir`].
2275///
2276/// Notable exception is made for situations where any of the directories
2277/// specified in the `path` could not be created as it was being created concurrently.
2278/// Such cases are considered to be successful. That is, calling `create_dir_all`
2279/// concurrently from multiple threads or processes is guaranteed not to fail
2280/// due to a race condition with itself.
2281///
2282/// [`fs::create_dir`]: create_dir
2283///
2284/// # Examples
2285///
2286/// ```no_run
2287/// use std::fs;
2288///
2289/// fn main() -> std::io::Result<()> {
2290/// fs::create_dir_all("/some/dir")?;
2291/// Ok(())
2292/// }
2293/// ```
2294#[stable(feature = "rust1", since = "1.0.0")]
2295pub fn create_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
2296 DirBuilder::new().recursive(true).create(path.as_ref())
2297}
2298
2299/// Removes an empty directory.
2300///
2301/// # Platform-specific behavior
2302///
2303/// This function currently corresponds to the `rmdir` function on Unix
2304/// and the `RemoveDirectory` function on Windows.
2305/// Note that, this [may change in the future][changes].
2306///
2307/// [changes]: io#platform-specific-behavior
2308///
2309/// # Errors
2310///
2311/// This function will return an error in the following situations, but is not
2312/// limited to just these cases:
2313///
2314/// * `path` doesn't exist.
2315/// * `path` isn't a directory.
2316/// * The user lacks permissions to remove the directory at the provided `path`.
2317/// * The directory isn't empty.
2318///
2319/// # Examples
2320///
2321/// ```no_run
2322/// use std::fs;
2323///
2324/// fn main() -> std::io::Result<()> {
2325/// fs::remove_dir("/some/dir")?;
2326/// Ok(())
2327/// }
2328/// ```
2329#[doc(alias = "rmdir")]
2330#[stable(feature = "rust1", since = "1.0.0")]
2331pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
2332 fs_imp::rmdir(path.as_ref())
2333}
2334
2335/// Removes a directory at this path, after removing all its contents. Use
2336/// carefully!
2337///
2338/// This function does **not** follow symbolic links and it will simply remove the
2339/// symbolic link itself.
2340///
2341/// # Platform-specific behavior
2342///
2343/// This function currently corresponds to `openat`, `fdopendir`, `unlinkat` and `lstat` functions
2344/// on Unix (except for macOS before version 10.10 and REDOX) and the `CreateFileW`,
2345/// `GetFileInformationByHandleEx`, `SetFileInformationByHandle`, and `NtCreateFile` functions on
2346/// Windows. Note that, this [may change in the future][changes].
2347///
2348/// [changes]: io#platform-specific-behavior
2349///
2350/// On macOS before version 10.10 and REDOX, as well as when running in Miri for any target, this
2351/// function is not protected against time-of-check to time-of-use (TOCTOU) race conditions, and
2352/// should not be used in security-sensitive code on those platforms. All other platforms are
2353/// protected.
2354///
2355/// # Errors
2356///
2357/// See [`fs::remove_file`] and [`fs::remove_dir`].
2358///
2359/// `remove_dir_all` will fail if `remove_dir` or `remove_file` fail on any constituent paths, including the root path.
2360/// As a result, the directory you are deleting must exist, meaning that this function is not idempotent.
2361///
2362/// Consider ignoring the error if validating the removal is not required for your use case.
2363///
2364/// [`fs::remove_file`]: remove_file
2365/// [`fs::remove_dir`]: remove_dir
2366///
2367/// # Examples
2368///
2369/// ```no_run
2370/// use std::fs;
2371///
2372/// fn main() -> std::io::Result<()> {
2373/// fs::remove_dir_all("/some/dir")?;
2374/// Ok(())
2375/// }
2376/// ```
2377#[stable(feature = "rust1", since = "1.0.0")]
2378pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
2379 fs_imp::remove_dir_all(path.as_ref())
2380}
2381
2382/// Returns an iterator over the entries within a directory.
2383///
2384/// The iterator will yield instances of <code>[io::Result]<[DirEntry]></code>.
2385/// New errors may be encountered after an iterator is initially constructed.
2386/// Entries for the current and parent directories (typically `.` and `..`) are
2387/// skipped.
2388///
2389/// # Platform-specific behavior
2390///
2391/// This function currently corresponds to the `opendir` function on Unix
2392/// and the `FindFirstFile` function on Windows. Advancing the iterator
2393/// currently corresponds to `readdir` on Unix and `FindNextFile` on Windows.
2394/// Note that, this [may change in the future][changes].
2395///
2396/// [changes]: io#platform-specific-behavior
2397///
2398/// The order in which this iterator returns entries is platform and filesystem
2399/// dependent.
2400///
2401/// # Errors
2402///
2403/// This function will return an error in the following situations, but is not
2404/// limited to just these cases:
2405///
2406/// * The provided `path` doesn't exist.
2407/// * The process lacks permissions to view the contents.
2408/// * The `path` points at a non-directory file.
2409///
2410/// # Examples
2411///
2412/// ```
2413/// use std::io;
2414/// use std::fs::{self, DirEntry};
2415/// use std::path::Path;
2416///
2417/// // one possible implementation of walking a directory only visiting files
2418/// fn visit_dirs(dir: &Path, cb: &dyn Fn(&DirEntry)) -> io::Result<()> {
2419/// if dir.is_dir() {
2420/// for entry in fs::read_dir(dir)? {
2421/// let entry = entry?;
2422/// let path = entry.path();
2423/// if path.is_dir() {
2424/// visit_dirs(&path, cb)?;
2425/// } else {
2426/// cb(&entry);
2427/// }
2428/// }
2429/// }
2430/// Ok(())
2431/// }
2432/// ```
2433///
2434/// ```rust,no_run
2435/// use std::{fs, io};
2436///
2437/// fn main() -> io::Result<()> {
2438/// let mut entries = fs::read_dir(".")?
2439/// .map(|res| res.map(|e| e.path()))
2440/// .collect::<Result<Vec<_>, io::Error>>()?;
2441///
2442/// // The order in which `read_dir` returns entries is not guaranteed. If reproducible
2443/// // ordering is required the entries should be explicitly sorted.
2444///
2445/// entries.sort();
2446///
2447/// // The entries have now been sorted by their path.
2448///
2449/// Ok(())
2450/// }
2451/// ```
2452#[stable(feature = "rust1", since = "1.0.0")]
2453pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
2454 fs_imp::readdir(path.as_ref()).map(op:ReadDir)
2455}
2456
2457/// Changes the permissions found on a file or a directory.
2458///
2459/// # Platform-specific behavior
2460///
2461/// This function currently corresponds to the `chmod` function on Unix
2462/// and the `SetFileAttributes` function on Windows.
2463/// Note that, this [may change in the future][changes].
2464///
2465/// [changes]: io#platform-specific-behavior
2466///
2467/// # Errors
2468///
2469/// This function will return an error in the following situations, but is not
2470/// limited to just these cases:
2471///
2472/// * `path` does not exist.
2473/// * The user lacks the permission to change attributes of the file.
2474///
2475/// # Examples
2476///
2477/// ```no_run
2478/// use std::fs;
2479///
2480/// fn main() -> std::io::Result<()> {
2481/// let mut perms = fs::metadata("foo.txt")?.permissions();
2482/// perms.set_readonly(true);
2483/// fs::set_permissions("foo.txt", perms)?;
2484/// Ok(())
2485/// }
2486/// ```
2487#[stable(feature = "set_permissions", since = "1.1.0")]
2488pub fn set_permissions<P: AsRef<Path>>(path: P, perm: Permissions) -> io::Result<()> {
2489 fs_imp::set_perm(p:path.as_ref(), perm:perm.0)
2490}
2491
2492impl DirBuilder {
2493 /// Creates a new set of options with default mode/security settings for all
2494 /// platforms and also non-recursive.
2495 ///
2496 /// # Examples
2497 ///
2498 /// ```
2499 /// use std::fs::DirBuilder;
2500 ///
2501 /// let builder = DirBuilder::new();
2502 /// ```
2503 #[stable(feature = "dir_builder", since = "1.6.0")]
2504 #[must_use]
2505 pub fn new() -> DirBuilder {
2506 DirBuilder { inner: fs_imp::DirBuilder::new(), recursive: false }
2507 }
2508
2509 /// Indicates that directories should be created recursively, creating all
2510 /// parent directories. Parents that do not exist are created with the same
2511 /// security and permissions settings.
2512 ///
2513 /// This option defaults to `false`.
2514 ///
2515 /// # Examples
2516 ///
2517 /// ```
2518 /// use std::fs::DirBuilder;
2519 ///
2520 /// let mut builder = DirBuilder::new();
2521 /// builder.recursive(true);
2522 /// ```
2523 #[stable(feature = "dir_builder", since = "1.6.0")]
2524 pub fn recursive(&mut self, recursive: bool) -> &mut Self {
2525 self.recursive = recursive;
2526 self
2527 }
2528
2529 /// Creates the specified directory with the options configured in this
2530 /// builder.
2531 ///
2532 /// It is considered an error if the directory already exists unless
2533 /// recursive mode is enabled.
2534 ///
2535 /// # Examples
2536 ///
2537 /// ```no_run
2538 /// use std::fs::{self, DirBuilder};
2539 ///
2540 /// let path = "/tmp/foo/bar/baz";
2541 /// DirBuilder::new()
2542 /// .recursive(true)
2543 /// .create(path).unwrap();
2544 ///
2545 /// assert!(fs::metadata(path).unwrap().is_dir());
2546 /// ```
2547 #[stable(feature = "dir_builder", since = "1.6.0")]
2548 pub fn create<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
2549 self._create(path.as_ref())
2550 }
2551
2552 fn _create(&self, path: &Path) -> io::Result<()> {
2553 if self.recursive { self.create_dir_all(path) } else { self.inner.mkdir(path) }
2554 }
2555
2556 fn create_dir_all(&self, path: &Path) -> io::Result<()> {
2557 if path == Path::new("") {
2558 return Ok(());
2559 }
2560
2561 match self.inner.mkdir(path) {
2562 Ok(()) => return Ok(()),
2563 Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
2564 Err(_) if path.is_dir() => return Ok(()),
2565 Err(e) => return Err(e),
2566 }
2567 match path.parent() {
2568 Some(p) => self.create_dir_all(p)?,
2569 None => {
2570 return Err(io::const_io_error!(
2571 io::ErrorKind::Uncategorized,
2572 "failed to create whole tree",
2573 ));
2574 }
2575 }
2576 match self.inner.mkdir(path) {
2577 Ok(()) => Ok(()),
2578 Err(_) if path.is_dir() => Ok(()),
2579 Err(e) => Err(e),
2580 }
2581 }
2582}
2583
2584impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
2585 #[inline]
2586 fn as_inner_mut(&mut self) -> &mut fs_imp::DirBuilder {
2587 &mut self.inner
2588 }
2589}
2590
2591/// Returns `Ok(true)` if the path points at an existing entity.
2592///
2593/// This function will traverse symbolic links to query information about the
2594/// destination file. In case of broken symbolic links this will return `Ok(false)`.
2595///
2596/// As opposed to the [`Path::exists`] method, this will only return `Ok(true)` or `Ok(false)`
2597/// if the path was _verified_ to exist or not exist. If its existence can neither be confirmed
2598/// nor denied, an `Err(_)` will be propagated instead. This can be the case if e.g. listing
2599/// permission is denied on one of the parent directories.
2600///
2601/// Note that while this avoids some pitfalls of the `exists()` method, it still can not
2602/// prevent time-of-check to time-of-use (TOCTOU) bugs. You should only use it in scenarios
2603/// where those bugs are not an issue.
2604///
2605/// # Examples
2606///
2607/// ```no_run
2608/// #![feature(fs_try_exists)]
2609/// use std::fs;
2610///
2611/// assert!(!fs::try_exists("does_not_exist.txt").expect("Can't check existence of file does_not_exist.txt"));
2612/// assert!(fs::try_exists("/root/secret_file.txt").is_err());
2613/// ```
2614///
2615/// [`Path::exists`]: crate::path::Path::exists
2616// FIXME: stabilization should modify documentation of `exists()` to recommend this method
2617// instead.
2618#[unstable(feature = "fs_try_exists", issue = "83186")]
2619#[inline]
2620pub fn try_exists<P: AsRef<Path>>(path: P) -> io::Result<bool> {
2621 fs_imp::try_exists(path.as_ref())
2622}
2623