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(
12 test,
13 not(any(
14 target_os = "emscripten",
15 target_os = "wasi",
16 target_env = "sgx",
17 target_os = "xous",
18 target_os = "trusty",
19 ))
20))]
21mod tests;
22
23use crate::ffi::OsString;
24use crate::fmt;
25use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
26use crate::path::{Path, PathBuf};
27use crate::sealed::Sealed;
28use crate::sync::Arc;
29use crate::sys::fs as fs_imp;
30use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
31use crate::time::SystemTime;
32
33/// An object providing access to an open file on the filesystem.
34///
35/// An instance of a `File` can be read and/or written depending on what options
36/// it was opened with. Files also implement [`Seek`] to alter the logical cursor
37/// that the file contains internally.
38///
39/// Files are automatically closed when they go out of scope. Errors detected
40/// on closing are ignored by the implementation of `Drop`. Use the method
41/// [`sync_all`] if these errors must be manually handled.
42///
43/// `File` does not buffer reads and writes. For efficiency, consider wrapping the
44/// file in a [`BufReader`] or [`BufWriter`] when performing many small [`read`]
45/// or [`write`] calls, unless unbuffered reads and writes are required.
46///
47/// # Examples
48///
49/// Creates a new file and write bytes to it (you can also use [`write`]):
50///
51/// ```no_run
52/// use std::fs::File;
53/// use std::io::prelude::*;
54///
55/// fn main() -> std::io::Result<()> {
56/// let mut file = File::create("foo.txt")?;
57/// file.write_all(b"Hello, world!")?;
58/// Ok(())
59/// }
60/// ```
61///
62/// Reads the contents of a file into a [`String`] (you can also use [`read`]):
63///
64/// ```no_run
65/// use std::fs::File;
66/// use std::io::prelude::*;
67///
68/// fn main() -> std::io::Result<()> {
69/// let mut file = File::open("foo.txt")?;
70/// let mut contents = String::new();
71/// file.read_to_string(&mut contents)?;
72/// assert_eq!(contents, "Hello, world!");
73/// Ok(())
74/// }
75/// ```
76///
77/// Using a buffered [`Read`]er:
78///
79/// ```no_run
80/// use std::fs::File;
81/// use std::io::BufReader;
82/// use std::io::prelude::*;
83///
84/// fn main() -> std::io::Result<()> {
85/// let file = File::open("foo.txt")?;
86/// let mut buf_reader = BufReader::new(file);
87/// let mut contents = String::new();
88/// buf_reader.read_to_string(&mut contents)?;
89/// assert_eq!(contents, "Hello, world!");
90/// Ok(())
91/// }
92/// ```
93///
94/// Note that, although read and write methods require a `&mut File`, because
95/// of the interfaces for [`Read`] and [`Write`], the holder of a `&File` can
96/// still modify the file, either through methods that take `&File` or by
97/// retrieving the underlying OS object and modifying the file that way.
98/// Additionally, many operating systems allow concurrent modification of files
99/// by different processes. Avoid assuming that holding a `&File` means that the
100/// file will not change.
101///
102/// # Platform-specific behavior
103///
104/// On Windows, the implementation of [`Read`] and [`Write`] traits for `File`
105/// perform synchronous I/O operations. Therefore the underlying file must not
106/// have been opened for asynchronous I/O (e.g. by using `FILE_FLAG_OVERLAPPED`).
107///
108/// [`BufReader`]: io::BufReader
109/// [`BufWriter`]: io::BufWriter
110/// [`sync_all`]: File::sync_all
111/// [`write`]: File::write
112/// [`read`]: File::read
113#[stable(feature = "rust1", since = "1.0.0")]
114#[cfg_attr(not(test), rustc_diagnostic_item = "File")]
115pub struct File {
116 inner: fs_imp::File,
117}
118
119/// Metadata information about a file.
120///
121/// This structure is returned from the [`metadata`] or
122/// [`symlink_metadata`] function or method and represents known
123/// metadata about a file such as its permissions, size, modification
124/// times, etc.
125#[stable(feature = "rust1", since = "1.0.0")]
126#[derive(Clone)]
127pub struct Metadata(fs_imp::FileAttr);
128
129/// Iterator over the entries in a directory.
130///
131/// This iterator is returned from the [`read_dir`] function of this module and
132/// will yield instances of <code>[io::Result]<[DirEntry]></code>. Through a [`DirEntry`]
133/// information like the entry's path and possibly other metadata can be
134/// learned.
135///
136/// The order in which this iterator returns entries is platform and filesystem
137/// dependent.
138///
139/// # Errors
140///
141/// This [`io::Result`] will be an [`Err`] if there's some sort of intermittent
142/// IO error during iteration.
143#[stable(feature = "rust1", since = "1.0.0")]
144#[derive(Debug)]
145pub struct ReadDir(fs_imp::ReadDir);
146
147/// Entries returned by the [`ReadDir`] iterator.
148///
149/// An instance of `DirEntry` represents an entry inside of a directory on the
150/// filesystem. Each entry can be inspected via methods to learn about the full
151/// path or possibly other metadata through per-platform extension traits.
152///
153/// # Platform-specific behavior
154///
155/// On Unix, the `DirEntry` struct contains an internal reference to the open
156/// directory. Holding `DirEntry` objects will consume a file handle even
157/// after the `ReadDir` iterator is dropped.
158///
159/// Note that this [may change in the future][changes].
160///
161/// [changes]: io#platform-specific-behavior
162#[stable(feature = "rust1", since = "1.0.0")]
163pub struct DirEntry(fs_imp::DirEntry);
164
165/// Options and flags which can be used to configure how a file is opened.
166///
167/// This builder exposes the ability to configure how a [`File`] is opened and
168/// what operations are permitted on the open file. The [`File::open`] and
169/// [`File::create`] methods are aliases for commonly used options using this
170/// builder.
171///
172/// Generally speaking, when using `OpenOptions`, you'll first call
173/// [`OpenOptions::new`], then chain calls to methods to set each option, then
174/// call [`OpenOptions::open`], passing the path of the file you're trying to
175/// open. This will give you a [`io::Result`] with a [`File`] inside that you
176/// can further operate on.
177///
178/// # Examples
179///
180/// Opening a file to read:
181///
182/// ```no_run
183/// use std::fs::OpenOptions;
184///
185/// let file = OpenOptions::new().read(true).open("foo.txt");
186/// ```
187///
188/// Opening a file for both reading and writing, as well as creating it if it
189/// doesn't exist:
190///
191/// ```no_run
192/// use std::fs::OpenOptions;
193///
194/// let file = OpenOptions::new()
195/// .read(true)
196/// .write(true)
197/// .create(true)
198/// .open("foo.txt");
199/// ```
200#[derive(Clone, Debug)]
201#[stable(feature = "rust1", since = "1.0.0")]
202#[cfg_attr(not(test), rustc_diagnostic_item = "FsOpenOptions")]
203pub struct OpenOptions(fs_imp::OpenOptions);
204
205/// Representation of the various timestamps on a file.
206#[derive(Copy, Clone, Debug, Default)]
207#[stable(feature = "file_set_times", since = "1.75.0")]
208pub struct FileTimes(fs_imp::FileTimes);
209
210/// Representation of the various permissions on a file.
211///
212/// This module only currently provides one bit of information,
213/// [`Permissions::readonly`], which is exposed on all currently supported
214/// platforms. Unix-specific functionality, such as mode bits, is available
215/// through the [`PermissionsExt`] trait.
216///
217/// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
218#[derive(Clone, PartialEq, Eq, Debug)]
219#[stable(feature = "rust1", since = "1.0.0")]
220#[cfg_attr(not(test), rustc_diagnostic_item = "FsPermissions")]
221pub struct Permissions(fs_imp::FilePermissions);
222
223/// A structure representing a type of file with accessors for each file type.
224/// It is returned by [`Metadata::file_type`] method.
225#[stable(feature = "file_type", since = "1.1.0")]
226#[derive(Copy, Clone, PartialEq, Eq, Hash)]
227#[cfg_attr(not(test), rustc_diagnostic_item = "FileType")]
228pub struct FileType(fs_imp::FileType);
229
230/// A builder used to create directories in various manners.
231///
232/// This builder also supports platform-specific options.
233#[stable(feature = "dir_builder", since = "1.6.0")]
234#[cfg_attr(not(test), rustc_diagnostic_item = "DirBuilder")]
235#[derive(Debug)]
236pub struct DirBuilder {
237 inner: fs_imp::DirBuilder,
238 recursive: bool,
239}
240
241/// Reads the entire contents of a file into a bytes vector.
242///
243/// This is a convenience function for using [`File::open`] and [`read_to_end`]
244/// with fewer imports and without an intermediate variable.
245///
246/// [`read_to_end`]: Read::read_to_end
247///
248/// # Errors
249///
250/// This function will return an error if `path` does not already exist.
251/// Other errors may also be returned according to [`OpenOptions::open`].
252///
253/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
254/// with automatic retries. See [io::Read] documentation for details.
255///
256/// # Examples
257///
258/// ```no_run
259/// use std::fs;
260///
261/// fn main() -> Result<(), Box<dyn std::error::Error + 'static>> {
262/// let data: Vec<u8> = fs::read("image.jpg")?;
263/// assert_eq!(data[0..3], [0xFF, 0xD8, 0xFF]);
264/// Ok(())
265/// }
266/// ```
267#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
268pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
269 fn inner(path: &Path) -> io::Result<Vec<u8>> {
270 let mut file: File = File::open(path)?;
271 let size: Option = file.metadata().map(|m: Metadata| m.len() as usize).ok();
272 let mut bytes: Vec = Vec::new();
273 bytes.try_reserve_exact(additional:size.unwrap_or(default:0))?;
274 io::default_read_to_end(&mut file, &mut bytes, size)?;
275 Ok(bytes)
276 }
277 inner(path.as_ref())
278}
279
280/// Reads the entire contents of a file into a string.
281///
282/// This is a convenience function for using [`File::open`] and [`read_to_string`]
283/// with fewer imports and without an intermediate variable.
284///
285/// [`read_to_string`]: Read::read_to_string
286///
287/// # Errors
288///
289/// This function will return an error if `path` does not already exist.
290/// Other errors may also be returned according to [`OpenOptions::open`].
291///
292/// If the contents of the file are not valid UTF-8, then an error will also be
293/// returned.
294///
295/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
296/// with automatic retries. See [io::Read] documentation for details.
297///
298/// # Examples
299///
300/// ```no_run
301/// use std::fs;
302/// use std::error::Error;
303///
304/// fn main() -> Result<(), Box<dyn Error>> {
305/// let message: String = fs::read_to_string("message.txt")?;
306/// println!("{}", message);
307/// Ok(())
308/// }
309/// ```
310#[stable(feature = "fs_read_write", since = "1.26.0")]
311pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
312 fn inner(path: &Path) -> io::Result<String> {
313 let mut file: File = File::open(path)?;
314 let size: Option = file.metadata().map(|m: Metadata| m.len() as usize).ok();
315 let mut string: String = String::new();
316 string.try_reserve_exact(additional:size.unwrap_or(default:0))?;
317 io::default_read_to_string(&mut file, &mut string, size)?;
318 Ok(string)
319 }
320 inner(path.as_ref())
321}
322
323/// Writes a slice as the entire contents of a file.
324///
325/// This function will create a file if it does not exist,
326/// and will entirely replace its contents if it does.
327///
328/// Depending on the platform, this function may fail if the
329/// full directory path does not exist.
330///
331/// This is a convenience function for using [`File::create`] and [`write_all`]
332/// with fewer imports.
333///
334/// [`write_all`]: Write::write_all
335///
336/// # Examples
337///
338/// ```no_run
339/// use std::fs;
340///
341/// fn main() -> std::io::Result<()> {
342/// fs::write("foo.txt", b"Lorem ipsum")?;
343/// fs::write("bar.txt", "dolor sit")?;
344/// Ok(())
345/// }
346/// ```
347#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
348pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> io::Result<()> {
349 fn inner(path: &Path, contents: &[u8]) -> io::Result<()> {
350 File::create(path)?.write_all(buf:contents)
351 }
352 inner(path.as_ref(), contents.as_ref())
353}
354
355impl File {
356 /// Attempts to open a file in read-only mode.
357 ///
358 /// See the [`OpenOptions::open`] method for more details.
359 ///
360 /// If you only need to read the entire file contents,
361 /// consider [`std::fs::read()`][self::read] or
362 /// [`std::fs::read_to_string()`][self::read_to_string] instead.
363 ///
364 /// # Errors
365 ///
366 /// This function will return an error if `path` does not already exist.
367 /// Other errors may also be returned according to [`OpenOptions::open`].
368 ///
369 /// # Examples
370 ///
371 /// ```no_run
372 /// use std::fs::File;
373 /// use std::io::Read;
374 ///
375 /// fn main() -> std::io::Result<()> {
376 /// let mut f = File::open("foo.txt")?;
377 /// let mut data = vec![];
378 /// f.read_to_end(&mut data)?;
379 /// Ok(())
380 /// }
381 /// ```
382 #[stable(feature = "rust1", since = "1.0.0")]
383 pub fn open<P: AsRef<Path>>(path: P) -> io::Result<File> {
384 OpenOptions::new().read(true).open(path.as_ref())
385 }
386
387 /// Attempts to open a file in read-only mode with buffering.
388 ///
389 /// See the [`OpenOptions::open`] method, the [`BufReader`][io::BufReader] type,
390 /// and the [`BufRead`][io::BufRead] trait for more details.
391 ///
392 /// If you only need to read the entire file contents,
393 /// consider [`std::fs::read()`][self::read] or
394 /// [`std::fs::read_to_string()`][self::read_to_string] instead.
395 ///
396 /// # Errors
397 ///
398 /// This function will return an error if `path` does not already exist,
399 /// or if memory allocation fails for the new buffer.
400 /// Other errors may also be returned according to [`OpenOptions::open`].
401 ///
402 /// # Examples
403 ///
404 /// ```no_run
405 /// #![feature(file_buffered)]
406 /// use std::fs::File;
407 /// use std::io::BufRead;
408 ///
409 /// fn main() -> std::io::Result<()> {
410 /// let mut f = File::open_buffered("foo.txt")?;
411 /// assert!(f.capacity() > 0);
412 /// for (line, i) in f.lines().zip(1..) {
413 /// println!("{i:6}: {}", line?);
414 /// }
415 /// Ok(())
416 /// }
417 /// ```
418 #[unstable(feature = "file_buffered", issue = "130804")]
419 pub fn open_buffered<P: AsRef<Path>>(path: P) -> io::Result<io::BufReader<File>> {
420 // Allocate the buffer *first* so we don't affect the filesystem otherwise.
421 let buffer = io::BufReader::<Self>::try_new_buffer()?;
422 let file = File::open(path)?;
423 Ok(io::BufReader::with_buffer(file, buffer))
424 }
425
426 /// Opens a file in write-only mode.
427 ///
428 /// This function will create a file if it does not exist,
429 /// and will truncate it if it does.
430 ///
431 /// Depending on the platform, this function may fail if the
432 /// full directory path does not exist.
433 /// See the [`OpenOptions::open`] function for more details.
434 ///
435 /// See also [`std::fs::write()`][self::write] for a simple function to
436 /// create a file with some given data.
437 ///
438 /// # Examples
439 ///
440 /// ```no_run
441 /// use std::fs::File;
442 /// use std::io::Write;
443 ///
444 /// fn main() -> std::io::Result<()> {
445 /// let mut f = File::create("foo.txt")?;
446 /// f.write_all(&1234_u32.to_be_bytes())?;
447 /// Ok(())
448 /// }
449 /// ```
450 #[stable(feature = "rust1", since = "1.0.0")]
451 pub fn create<P: AsRef<Path>>(path: P) -> io::Result<File> {
452 OpenOptions::new().write(true).create(true).truncate(true).open(path.as_ref())
453 }
454
455 /// Opens a file in write-only mode with buffering.
456 ///
457 /// This function will create a file if it does not exist,
458 /// and will truncate it if it does.
459 ///
460 /// Depending on the platform, this function may fail if the
461 /// full directory path does not exist.
462 ///
463 /// See the [`OpenOptions::open`] method and the
464 /// [`BufWriter`][io::BufWriter] type for more details.
465 ///
466 /// See also [`std::fs::write()`][self::write] for a simple function to
467 /// create a file with some given data.
468 ///
469 /// # Examples
470 ///
471 /// ```no_run
472 /// #![feature(file_buffered)]
473 /// use std::fs::File;
474 /// use std::io::Write;
475 ///
476 /// fn main() -> std::io::Result<()> {
477 /// let mut f = File::create_buffered("foo.txt")?;
478 /// assert!(f.capacity() > 0);
479 /// for i in 0..100 {
480 /// writeln!(&mut f, "{i}")?;
481 /// }
482 /// f.flush()?;
483 /// Ok(())
484 /// }
485 /// ```
486 #[unstable(feature = "file_buffered", issue = "130804")]
487 pub fn create_buffered<P: AsRef<Path>>(path: P) -> io::Result<io::BufWriter<File>> {
488 // Allocate the buffer *first* so we don't affect the filesystem otherwise.
489 let buffer = io::BufWriter::<Self>::try_new_buffer()?;
490 let file = File::create(path)?;
491 Ok(io::BufWriter::with_buffer(file, buffer))
492 }
493
494 /// Creates a new file in read-write mode; error if the file exists.
495 ///
496 /// This function will create a file if it does not exist, or return an error if it does. This
497 /// way, if the call succeeds, the file returned is guaranteed to be new.
498 /// If a file exists at the target location, creating a new file will fail with [`AlreadyExists`]
499 /// or another error based on the situation. See [`OpenOptions::open`] for a
500 /// non-exhaustive list of likely errors.
501 ///
502 /// This option is useful because it is atomic. Otherwise between checking whether a file
503 /// exists and creating a new one, the file may have been created by another process (a TOCTOU
504 /// race condition / attack).
505 ///
506 /// This can also be written using
507 /// `File::options().read(true).write(true).create_new(true).open(...)`.
508 ///
509 /// [`AlreadyExists`]: crate::io::ErrorKind::AlreadyExists
510 ///
511 /// # Examples
512 ///
513 /// ```no_run
514 /// use std::fs::File;
515 /// use std::io::Write;
516 ///
517 /// fn main() -> std::io::Result<()> {
518 /// let mut f = File::create_new("foo.txt")?;
519 /// f.write_all("Hello, world!".as_bytes())?;
520 /// Ok(())
521 /// }
522 /// ```
523 #[stable(feature = "file_create_new", since = "1.77.0")]
524 pub fn create_new<P: AsRef<Path>>(path: P) -> io::Result<File> {
525 OpenOptions::new().read(true).write(true).create_new(true).open(path.as_ref())
526 }
527
528 /// Returns a new OpenOptions object.
529 ///
530 /// This function returns a new OpenOptions object that you can use to
531 /// open or create a file with specific options if `open()` or `create()`
532 /// are not appropriate.
533 ///
534 /// It is equivalent to `OpenOptions::new()`, but allows you to write more
535 /// readable code. Instead of
536 /// `OpenOptions::new().append(true).open("example.log")`,
537 /// you can write `File::options().append(true).open("example.log")`. This
538 /// also avoids the need to import `OpenOptions`.
539 ///
540 /// See the [`OpenOptions::new`] function for more details.
541 ///
542 /// # Examples
543 ///
544 /// ```no_run
545 /// use std::fs::File;
546 /// use std::io::Write;
547 ///
548 /// fn main() -> std::io::Result<()> {
549 /// let mut f = File::options().append(true).open("example.log")?;
550 /// writeln!(&mut f, "new line")?;
551 /// Ok(())
552 /// }
553 /// ```
554 #[must_use]
555 #[stable(feature = "with_options", since = "1.58.0")]
556 #[cfg_attr(not(test), rustc_diagnostic_item = "file_options")]
557 pub fn options() -> OpenOptions {
558 OpenOptions::new()
559 }
560
561 /// Attempts to sync all OS-internal file content and metadata to disk.
562 ///
563 /// This function will attempt to ensure that all in-memory data reaches the
564 /// filesystem before returning.
565 ///
566 /// This can be used to handle errors that would otherwise only be caught
567 /// when the `File` is closed, as dropping a `File` will ignore all errors.
568 /// Note, however, that `sync_all` is generally more expensive than closing
569 /// a file by dropping it, because the latter is not required to block until
570 /// the data has been written to the filesystem.
571 ///
572 /// If synchronizing the metadata is not required, use [`sync_data`] instead.
573 ///
574 /// [`sync_data`]: File::sync_data
575 ///
576 /// # Examples
577 ///
578 /// ```no_run
579 /// use std::fs::File;
580 /// use std::io::prelude::*;
581 ///
582 /// fn main() -> std::io::Result<()> {
583 /// let mut f = File::create("foo.txt")?;
584 /// f.write_all(b"Hello, world!")?;
585 ///
586 /// f.sync_all()?;
587 /// Ok(())
588 /// }
589 /// ```
590 #[stable(feature = "rust1", since = "1.0.0")]
591 #[doc(alias = "fsync")]
592 pub fn sync_all(&self) -> io::Result<()> {
593 self.inner.fsync()
594 }
595
596 /// This function is similar to [`sync_all`], except that it might not
597 /// synchronize file metadata to the filesystem.
598 ///
599 /// This is intended for use cases that must synchronize content, but don't
600 /// need the metadata on disk. The goal of this method is to reduce disk
601 /// operations.
602 ///
603 /// Note that some platforms may simply implement this in terms of
604 /// [`sync_all`].
605 ///
606 /// [`sync_all`]: File::sync_all
607 ///
608 /// # Examples
609 ///
610 /// ```no_run
611 /// use std::fs::File;
612 /// use std::io::prelude::*;
613 ///
614 /// fn main() -> std::io::Result<()> {
615 /// let mut f = File::create("foo.txt")?;
616 /// f.write_all(b"Hello, world!")?;
617 ///
618 /// f.sync_data()?;
619 /// Ok(())
620 /// }
621 /// ```
622 #[stable(feature = "rust1", since = "1.0.0")]
623 #[doc(alias = "fdatasync")]
624 pub fn sync_data(&self) -> io::Result<()> {
625 self.inner.datasync()
626 }
627
628 /// Acquire an exclusive lock on the file. Blocks until the lock can be acquired.
629 ///
630 /// This acquires an exclusive lock; no other file handle to this file may acquire another lock.
631 ///
632 /// This lock may be advisory or mandatory. This lock is meant to interact with [`lock`],
633 /// [`try_lock`], [`lock_shared`], [`try_lock_shared`], and [`unlock`]. Its interactions with
634 /// other methods, such as [`read`] and [`write`] are platform specific, and it may or may not
635 /// cause non-lockholders to block.
636 ///
637 /// If this file handle/descriptor, or a clone of it, already holds an lock the exact behavior
638 /// is unspecified and platform dependent, including the possibility that it will deadlock.
639 /// However, if this method returns, then an exclusive lock is held.
640 ///
641 /// If the file not open for writing, it is unspecified whether this function returns an error.
642 ///
643 /// The lock will be released when this file (along with any other file descriptors/handles
644 /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called.
645 ///
646 /// # Platform-specific behavior
647 ///
648 /// This function currently corresponds to the `flock` function on Unix with the `LOCK_EX` flag,
649 /// and the `LockFileEx` function on Windows with the `LOCKFILE_EXCLUSIVE_LOCK` flag. Note that,
650 /// this [may change in the future][changes].
651 ///
652 /// On Windows, locking a file will fail if the file is opened only for append. To lock a file,
653 /// open it with one of `.read(true)`, `.read(true).append(true)`, or `.write(true)`.
654 ///
655 /// [changes]: io#platform-specific-behavior
656 ///
657 /// [`lock`]: File::lock
658 /// [`lock_shared`]: File::lock_shared
659 /// [`try_lock`]: File::try_lock
660 /// [`try_lock_shared`]: File::try_lock_shared
661 /// [`unlock`]: File::unlock
662 /// [`read`]: Read::read
663 /// [`write`]: Write::write
664 ///
665 /// # Examples
666 ///
667 /// ```no_run
668 /// #![feature(file_lock)]
669 /// use std::fs::File;
670 ///
671 /// fn main() -> std::io::Result<()> {
672 /// let f = File::create("foo.txt")?;
673 /// f.lock()?;
674 /// Ok(())
675 /// }
676 /// ```
677 #[unstable(feature = "file_lock", issue = "130994")]
678 pub fn lock(&self) -> io::Result<()> {
679 self.inner.lock()
680 }
681
682 /// Acquire a shared (non-exclusive) lock on the file. Blocks until the lock can be acquired.
683 ///
684 /// This acquires a shared lock; more than one file handle may hold a shared lock, but none may
685 /// hold an exclusive lock at the same time.
686 ///
687 /// This lock may be advisory or mandatory. This lock is meant to interact with [`lock`],
688 /// [`try_lock`], [`lock_shared`], [`try_lock_shared`], and [`unlock`]. Its interactions with
689 /// other methods, such as [`read`] and [`write`] are platform specific, and it may or may not
690 /// cause non-lockholders to block.
691 ///
692 /// If this file handle/descriptor, or a clone of it, already holds an lock, the exact behavior
693 /// is unspecified and platform dependent, including the possibility that it will deadlock.
694 /// However, if this method returns, then a shared lock is held.
695 ///
696 /// The lock will be released when this file (along with any other file descriptors/handles
697 /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called.
698 ///
699 /// # Platform-specific behavior
700 ///
701 /// This function currently corresponds to the `flock` function on Unix with the `LOCK_SH` flag,
702 /// and the `LockFileEx` function on Windows. Note that, this
703 /// [may change in the future][changes].
704 ///
705 /// On Windows, locking a file will fail if the file is opened only for append. To lock a file,
706 /// open it with one of `.read(true)`, `.read(true).append(true)`, or `.write(true)`.
707 ///
708 /// [changes]: io#platform-specific-behavior
709 ///
710 /// [`lock`]: File::lock
711 /// [`lock_shared`]: File::lock_shared
712 /// [`try_lock`]: File::try_lock
713 /// [`try_lock_shared`]: File::try_lock_shared
714 /// [`unlock`]: File::unlock
715 /// [`read`]: Read::read
716 /// [`write`]: Write::write
717 ///
718 /// # Examples
719 ///
720 /// ```no_run
721 /// #![feature(file_lock)]
722 /// use std::fs::File;
723 ///
724 /// fn main() -> std::io::Result<()> {
725 /// let f = File::open("foo.txt")?;
726 /// f.lock_shared()?;
727 /// Ok(())
728 /// }
729 /// ```
730 #[unstable(feature = "file_lock", issue = "130994")]
731 pub fn lock_shared(&self) -> io::Result<()> {
732 self.inner.lock_shared()
733 }
734
735 /// Try to acquire an exclusive lock on the file.
736 ///
737 /// Returns `Ok(false)` if a different lock is already held on this file (via another
738 /// handle/descriptor).
739 ///
740 /// This acquires an exclusive lock; no other file handle to this file may acquire another lock.
741 ///
742 /// This lock may be advisory or mandatory. This lock is meant to interact with [`lock`],
743 /// [`try_lock`], [`lock_shared`], [`try_lock_shared`], and [`unlock`]. Its interactions with
744 /// other methods, such as [`read`] and [`write`] are platform specific, and it may or may not
745 /// cause non-lockholders to block.
746 ///
747 /// If this file handle/descriptor, or a clone of it, already holds an lock, the exact behavior
748 /// is unspecified and platform dependent, including the possibility that it will deadlock.
749 /// However, if this method returns `Ok(true)`, then it has acquired an exclusive lock.
750 ///
751 /// If the file not open for writing, it is unspecified whether this function returns an error.
752 ///
753 /// The lock will be released when this file (along with any other file descriptors/handles
754 /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called.
755 ///
756 /// # Platform-specific behavior
757 ///
758 /// This function currently corresponds to the `flock` function on Unix with the `LOCK_EX` and
759 /// `LOCK_NB` flags, and the `LockFileEx` function on Windows with the `LOCKFILE_EXCLUSIVE_LOCK`
760 /// and `LOCKFILE_FAIL_IMMEDIATELY` flags. Note that, this
761 /// [may change in the future][changes].
762 ///
763 /// On Windows, locking a file will fail if the file is opened only for append. To lock a file,
764 /// open it with one of `.read(true)`, `.read(true).append(true)`, or `.write(true)`.
765 ///
766 /// [changes]: io#platform-specific-behavior
767 ///
768 /// [`lock`]: File::lock
769 /// [`lock_shared`]: File::lock_shared
770 /// [`try_lock`]: File::try_lock
771 /// [`try_lock_shared`]: File::try_lock_shared
772 /// [`unlock`]: File::unlock
773 /// [`read`]: Read::read
774 /// [`write`]: Write::write
775 ///
776 /// # Examples
777 ///
778 /// ```no_run
779 /// #![feature(file_lock)]
780 /// use std::fs::File;
781 ///
782 /// fn main() -> std::io::Result<()> {
783 /// let f = File::create("foo.txt")?;
784 /// f.try_lock()?;
785 /// Ok(())
786 /// }
787 /// ```
788 #[unstable(feature = "file_lock", issue = "130994")]
789 pub fn try_lock(&self) -> io::Result<bool> {
790 self.inner.try_lock()
791 }
792
793 /// Try to acquire a shared (non-exclusive) lock on the file.
794 ///
795 /// Returns `Ok(false)` if an exclusive lock is already held on this file (via another
796 /// handle/descriptor).
797 ///
798 /// This acquires a shared lock; more than one file handle may hold a shared lock, but none may
799 /// hold an exclusive lock at the same time.
800 ///
801 /// This lock may be advisory or mandatory. This lock is meant to interact with [`lock`],
802 /// [`try_lock`], [`lock_shared`], [`try_lock_shared`], and [`unlock`]. Its interactions with
803 /// other methods, such as [`read`] and [`write`] are platform specific, and it may or may not
804 /// cause non-lockholders to block.
805 ///
806 /// If this file handle, or a clone of it, already holds an lock, the exact behavior is
807 /// unspecified and platform dependent, including the possibility that it will deadlock.
808 /// However, if this method returns `Ok(true)`, then it has acquired a shared lock.
809 ///
810 /// The lock will be released when this file (along with any other file descriptors/handles
811 /// duplicated or inherited from it) is closed, or if the [`unlock`] method is called.
812 ///
813 /// # Platform-specific behavior
814 ///
815 /// This function currently corresponds to the `flock` function on Unix with the `LOCK_SH` and
816 /// `LOCK_NB` flags, and the `LockFileEx` function on Windows with the
817 /// `LOCKFILE_FAIL_IMMEDIATELY` flag. Note that, this
818 /// [may change in the future][changes].
819 ///
820 /// On Windows, locking a file will fail if the file is opened only for append. To lock a file,
821 /// open it with one of `.read(true)`, `.read(true).append(true)`, or `.write(true)`.
822 ///
823 /// [changes]: io#platform-specific-behavior
824 ///
825 /// [`lock`]: File::lock
826 /// [`lock_shared`]: File::lock_shared
827 /// [`try_lock`]: File::try_lock
828 /// [`try_lock_shared`]: File::try_lock_shared
829 /// [`unlock`]: File::unlock
830 /// [`read`]: Read::read
831 /// [`write`]: Write::write
832 ///
833 /// # Examples
834 ///
835 /// ```no_run
836 /// #![feature(file_lock)]
837 /// use std::fs::File;
838 ///
839 /// fn main() -> std::io::Result<()> {
840 /// let f = File::open("foo.txt")?;
841 /// f.try_lock_shared()?;
842 /// Ok(())
843 /// }
844 /// ```
845 #[unstable(feature = "file_lock", issue = "130994")]
846 pub fn try_lock_shared(&self) -> io::Result<bool> {
847 self.inner.try_lock_shared()
848 }
849
850 /// Release all locks on the file.
851 ///
852 /// All locks are released when the file (along with any other file descriptors/handles
853 /// duplicated or inherited from it) is closed. This method allows releasing locks without
854 /// closing the file.
855 ///
856 /// If no lock is currently held via this file descriptor/handle, this method may return an
857 /// error, or may return successfully without taking any action.
858 ///
859 /// # Platform-specific behavior
860 ///
861 /// This function currently corresponds to the `flock` function on Unix with the `LOCK_UN` flag,
862 /// and the `UnlockFile` function on Windows. Note that, this
863 /// [may change in the future][changes].
864 ///
865 /// On Windows, locking a file will fail if the file is opened only for append. To lock a file,
866 /// open it with one of `.read(true)`, `.read(true).append(true)`, or `.write(true)`.
867 ///
868 /// [changes]: io#platform-specific-behavior
869 ///
870 /// # Examples
871 ///
872 /// ```no_run
873 /// #![feature(file_lock)]
874 /// use std::fs::File;
875 ///
876 /// fn main() -> std::io::Result<()> {
877 /// let f = File::open("foo.txt")?;
878 /// f.lock()?;
879 /// f.unlock()?;
880 /// Ok(())
881 /// }
882 /// ```
883 #[unstable(feature = "file_lock", issue = "130994")]
884 pub fn unlock(&self) -> io::Result<()> {
885 self.inner.unlock()
886 }
887
888 /// Truncates or extends the underlying file, updating the size of
889 /// this file to become `size`.
890 ///
891 /// If the `size` is less than the current file's size, then the file will
892 /// be shrunk. If it is greater than the current file's size, then the file
893 /// will be extended to `size` and have all of the intermediate data filled
894 /// in with 0s.
895 ///
896 /// The file's cursor isn't changed. In particular, if the cursor was at the
897 /// end and the file is shrunk using this operation, the cursor will now be
898 /// past the end.
899 ///
900 /// # Errors
901 ///
902 /// This function will return an error if the file is not opened for writing.
903 /// Also, [`std::io::ErrorKind::InvalidInput`](crate::io::ErrorKind::InvalidInput)
904 /// will be returned if the desired length would cause an overflow due to
905 /// the implementation specifics.
906 ///
907 /// # Examples
908 ///
909 /// ```no_run
910 /// use std::fs::File;
911 ///
912 /// fn main() -> std::io::Result<()> {
913 /// let mut f = File::create("foo.txt")?;
914 /// f.set_len(10)?;
915 /// Ok(())
916 /// }
917 /// ```
918 ///
919 /// Note that this method alters the content of the underlying file, even
920 /// though it takes `&self` rather than `&mut self`.
921 #[stable(feature = "rust1", since = "1.0.0")]
922 pub fn set_len(&self, size: u64) -> io::Result<()> {
923 self.inner.truncate(size)
924 }
925
926 /// Queries metadata about the underlying file.
927 ///
928 /// # Examples
929 ///
930 /// ```no_run
931 /// use std::fs::File;
932 ///
933 /// fn main() -> std::io::Result<()> {
934 /// let mut f = File::open("foo.txt")?;
935 /// let metadata = f.metadata()?;
936 /// Ok(())
937 /// }
938 /// ```
939 #[stable(feature = "rust1", since = "1.0.0")]
940 pub fn metadata(&self) -> io::Result<Metadata> {
941 self.inner.file_attr().map(Metadata)
942 }
943
944 /// Creates a new `File` instance that shares the same underlying file handle
945 /// as the existing `File` instance. Reads, writes, and seeks will affect
946 /// both `File` instances simultaneously.
947 ///
948 /// # Examples
949 ///
950 /// Creates two handles for a file named `foo.txt`:
951 ///
952 /// ```no_run
953 /// use std::fs::File;
954 ///
955 /// fn main() -> std::io::Result<()> {
956 /// let mut file = File::open("foo.txt")?;
957 /// let file_copy = file.try_clone()?;
958 /// Ok(())
959 /// }
960 /// ```
961 ///
962 /// Assuming there’s a file named `foo.txt` with contents `abcdef\n`, create
963 /// two handles, seek one of them, and read the remaining bytes from the
964 /// other handle:
965 ///
966 /// ```no_run
967 /// use std::fs::File;
968 /// use std::io::SeekFrom;
969 /// use std::io::prelude::*;
970 ///
971 /// fn main() -> std::io::Result<()> {
972 /// let mut file = File::open("foo.txt")?;
973 /// let mut file_copy = file.try_clone()?;
974 ///
975 /// file.seek(SeekFrom::Start(3))?;
976 ///
977 /// let mut contents = vec![];
978 /// file_copy.read_to_end(&mut contents)?;
979 /// assert_eq!(contents, b"def\n");
980 /// Ok(())
981 /// }
982 /// ```
983 #[stable(feature = "file_try_clone", since = "1.9.0")]
984 pub fn try_clone(&self) -> io::Result<File> {
985 Ok(File { inner: self.inner.duplicate()? })
986 }
987
988 /// Changes the permissions on the underlying file.
989 ///
990 /// # Platform-specific behavior
991 ///
992 /// This function currently corresponds to the `fchmod` function on Unix and
993 /// the `SetFileInformationByHandle` function on Windows. Note that, this
994 /// [may change in the future][changes].
995 ///
996 /// [changes]: io#platform-specific-behavior
997 ///
998 /// # Errors
999 ///
1000 /// This function will return an error if the user lacks permission change
1001 /// attributes on the underlying file. It may also return an error in other
1002 /// os-specific unspecified cases.
1003 ///
1004 /// # Examples
1005 ///
1006 /// ```no_run
1007 /// fn main() -> std::io::Result<()> {
1008 /// use std::fs::File;
1009 ///
1010 /// let file = File::open("foo.txt")?;
1011 /// let mut perms = file.metadata()?.permissions();
1012 /// perms.set_readonly(true);
1013 /// file.set_permissions(perms)?;
1014 /// Ok(())
1015 /// }
1016 /// ```
1017 ///
1018 /// Note that this method alters the permissions of the underlying file,
1019 /// even though it takes `&self` rather than `&mut self`.
1020 #[doc(alias = "fchmod", alias = "SetFileInformationByHandle")]
1021 #[stable(feature = "set_permissions_atomic", since = "1.16.0")]
1022 pub fn set_permissions(&self, perm: Permissions) -> io::Result<()> {
1023 self.inner.set_permissions(perm.0)
1024 }
1025
1026 /// Changes the timestamps of the underlying file.
1027 ///
1028 /// # Platform-specific behavior
1029 ///
1030 /// This function currently corresponds to the `futimens` function on Unix (falling back to
1031 /// `futimes` on macOS before 10.13) and the `SetFileTime` function on Windows. Note that this
1032 /// [may change in the future][changes].
1033 ///
1034 /// [changes]: io#platform-specific-behavior
1035 ///
1036 /// # Errors
1037 ///
1038 /// This function will return an error if the user lacks permission to change timestamps on the
1039 /// underlying file. It may also return an error in other os-specific unspecified cases.
1040 ///
1041 /// This function may return an error if the operating system lacks support to change one or
1042 /// more of the timestamps set in the `FileTimes` structure.
1043 ///
1044 /// # Examples
1045 ///
1046 /// ```no_run
1047 /// fn main() -> std::io::Result<()> {
1048 /// use std::fs::{self, File, FileTimes};
1049 ///
1050 /// let src = fs::metadata("src")?;
1051 /// let dest = File::options().write(true).open("dest")?;
1052 /// let times = FileTimes::new()
1053 /// .set_accessed(src.accessed()?)
1054 /// .set_modified(src.modified()?);
1055 /// dest.set_times(times)?;
1056 /// Ok(())
1057 /// }
1058 /// ```
1059 #[stable(feature = "file_set_times", since = "1.75.0")]
1060 #[doc(alias = "futimens")]
1061 #[doc(alias = "futimes")]
1062 #[doc(alias = "SetFileTime")]
1063 pub fn set_times(&self, times: FileTimes) -> io::Result<()> {
1064 self.inner.set_times(times.0)
1065 }
1066
1067 /// Changes the modification time of the underlying file.
1068 ///
1069 /// This is an alias for `set_times(FileTimes::new().set_modified(time))`.
1070 #[stable(feature = "file_set_times", since = "1.75.0")]
1071 #[inline]
1072 pub fn set_modified(&self, time: SystemTime) -> io::Result<()> {
1073 self.set_times(FileTimes::new().set_modified(time))
1074 }
1075}
1076
1077// In addition to the `impl`s here, `File` also has `impl`s for
1078// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
1079// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
1080// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
1081// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
1082
1083impl AsInner<fs_imp::File> for File {
1084 #[inline]
1085 fn as_inner(&self) -> &fs_imp::File {
1086 &self.inner
1087 }
1088}
1089impl FromInner<fs_imp::File> for File {
1090 fn from_inner(f: fs_imp::File) -> File {
1091 File { inner: f }
1092 }
1093}
1094impl IntoInner<fs_imp::File> for File {
1095 fn into_inner(self) -> fs_imp::File {
1096 self.inner
1097 }
1098}
1099
1100#[stable(feature = "rust1", since = "1.0.0")]
1101impl fmt::Debug for File {
1102 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1103 self.inner.fmt(f)
1104 }
1105}
1106
1107/// Indicates how much extra capacity is needed to read the rest of the file.
1108fn buffer_capacity_required(mut file: &File) -> Option<usize> {
1109 let size: u64 = file.metadata().map(|m: Metadata| m.len()).ok()?;
1110 let pos: u64 = file.stream_position().ok()?;
1111 // Don't worry about `usize` overflow because reading will fail regardless
1112 // in that case.
1113 Some(size.saturating_sub(pos) as usize)
1114}
1115
1116#[stable(feature = "rust1", since = "1.0.0")]
1117impl Read for &File {
1118 /// Reads some bytes from the file.
1119 ///
1120 /// See [`Read::read`] docs for more info.
1121 ///
1122 /// # Platform-specific behavior
1123 ///
1124 /// This function currently corresponds to the `read` function on Unix and
1125 /// the `NtReadFile` function on Windows. Note that this [may change in
1126 /// the future][changes].
1127 ///
1128 /// [changes]: io#platform-specific-behavior
1129 #[inline]
1130 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
1131 self.inner.read(buf)
1132 }
1133
1134 /// Like `read`, except that it reads into a slice of buffers.
1135 ///
1136 /// See [`Read::read_vectored`] docs for more info.
1137 ///
1138 /// # Platform-specific behavior
1139 ///
1140 /// This function currently corresponds to the `readv` function on Unix and
1141 /// falls back to the `read` implementation on Windows. Note that this
1142 /// [may change in the future][changes].
1143 ///
1144 /// [changes]: io#platform-specific-behavior
1145 #[inline]
1146 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
1147 self.inner.read_vectored(bufs)
1148 }
1149
1150 #[inline]
1151 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
1152 self.inner.read_buf(cursor)
1153 }
1154
1155 /// Determines if `File` has an efficient `read_vectored` implementation.
1156 ///
1157 /// See [`Read::is_read_vectored`] docs for more info.
1158 ///
1159 /// # Platform-specific behavior
1160 ///
1161 /// This function currently returns `true` on Unix an `false` on Windows.
1162 /// Note that this [may change in the future][changes].
1163 ///
1164 /// [changes]: io#platform-specific-behavior
1165 #[inline]
1166 fn is_read_vectored(&self) -> bool {
1167 self.inner.is_read_vectored()
1168 }
1169
1170 // Reserves space in the buffer based on the file size when available.
1171 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
1172 let size = buffer_capacity_required(self);
1173 buf.try_reserve(size.unwrap_or(0))?;
1174 io::default_read_to_end(self, buf, size)
1175 }
1176
1177 // Reserves space in the buffer based on the file size when available.
1178 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
1179 let size = buffer_capacity_required(self);
1180 buf.try_reserve(size.unwrap_or(0))?;
1181 io::default_read_to_string(self, buf, size)
1182 }
1183}
1184#[stable(feature = "rust1", since = "1.0.0")]
1185impl Write for &File {
1186 /// Writes some bytes to the file.
1187 ///
1188 /// See [`Write::write`] docs for more info.
1189 ///
1190 /// # Platform-specific behavior
1191 ///
1192 /// This function currently corresponds to the `write` function on Unix and
1193 /// the `NtWriteFile` function on Windows. Note that this [may change in
1194 /// the future][changes].
1195 ///
1196 /// [changes]: io#platform-specific-behavior
1197 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
1198 self.inner.write(buf)
1199 }
1200
1201 /// Like `write`, except that it writes into a slice of buffers.
1202 ///
1203 /// See [`Write::write_vectored`] docs for more info.
1204 ///
1205 /// # Platform-specific behavior
1206 ///
1207 /// This function currently corresponds to the `writev` function on Unix
1208 /// and falls back to the `write` implementation on Windows. Note that this
1209 /// [may change in the future][changes].
1210 ///
1211 /// [changes]: io#platform-specific-behavior
1212 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
1213 self.inner.write_vectored(bufs)
1214 }
1215
1216 /// Determines if `File` has an efficient `write_vectored` implementation.
1217 ///
1218 /// See [`Write::is_write_vectored`] docs for more info.
1219 ///
1220 /// # Platform-specific behavior
1221 ///
1222 /// This function currently returns `true` on Unix an `false` on Windows.
1223 /// Note that this [may change in the future][changes].
1224 ///
1225 /// [changes]: io#platform-specific-behavior
1226 #[inline]
1227 fn is_write_vectored(&self) -> bool {
1228 self.inner.is_write_vectored()
1229 }
1230
1231 /// Flushes the file, ensuring that all intermediately buffered contents
1232 /// reach their destination.
1233 ///
1234 /// See [`Write::flush`] docs for more info.
1235 ///
1236 /// # Platform-specific behavior
1237 ///
1238 /// Since a `File` structure doesn't contain any buffers, this function is
1239 /// currently a no-op on Unix and Windows. Note that this [may change in
1240 /// the future][changes].
1241 ///
1242 /// [changes]: io#platform-specific-behavior
1243 #[inline]
1244 fn flush(&mut self) -> io::Result<()> {
1245 self.inner.flush()
1246 }
1247}
1248#[stable(feature = "rust1", since = "1.0.0")]
1249impl Seek for &File {
1250 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
1251 self.inner.seek(pos)
1252 }
1253 fn stream_position(&mut self) -> io::Result<u64> {
1254 self.inner.tell()
1255 }
1256}
1257
1258#[stable(feature = "rust1", since = "1.0.0")]
1259impl Read for File {
1260 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
1261 (&*self).read(buf)
1262 }
1263 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
1264 (&*self).read_vectored(bufs)
1265 }
1266 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
1267 (&*self).read_buf(cursor)
1268 }
1269 #[inline]
1270 fn is_read_vectored(&self) -> bool {
1271 (&&*self).is_read_vectored()
1272 }
1273 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
1274 (&*self).read_to_end(buf)
1275 }
1276 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
1277 (&*self).read_to_string(buf)
1278 }
1279}
1280#[stable(feature = "rust1", since = "1.0.0")]
1281impl Write for File {
1282 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
1283 (&*self).write(buf)
1284 }
1285 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
1286 (&*self).write_vectored(bufs)
1287 }
1288 #[inline]
1289 fn is_write_vectored(&self) -> bool {
1290 (&&*self).is_write_vectored()
1291 }
1292 #[inline]
1293 fn flush(&mut self) -> io::Result<()> {
1294 (&*self).flush()
1295 }
1296}
1297#[stable(feature = "rust1", since = "1.0.0")]
1298impl Seek for File {
1299 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
1300 (&*self).seek(pos)
1301 }
1302 fn stream_position(&mut self) -> io::Result<u64> {
1303 (&*self).stream_position()
1304 }
1305}
1306
1307#[stable(feature = "io_traits_arc", since = "1.73.0")]
1308impl Read for Arc<File> {
1309 fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
1310 (&**self).read(buf)
1311 }
1312 fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
1313 (&**self).read_vectored(bufs)
1314 }
1315 fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
1316 (&**self).read_buf(cursor)
1317 }
1318 #[inline]
1319 fn is_read_vectored(&self) -> bool {
1320 (&**self).is_read_vectored()
1321 }
1322 fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
1323 (&**self).read_to_end(buf)
1324 }
1325 fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
1326 (&**self).read_to_string(buf)
1327 }
1328}
1329#[stable(feature = "io_traits_arc", since = "1.73.0")]
1330impl Write for Arc<File> {
1331 fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
1332 (&**self).write(buf)
1333 }
1334 fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
1335 (&**self).write_vectored(bufs)
1336 }
1337 #[inline]
1338 fn is_write_vectored(&self) -> bool {
1339 (&**self).is_write_vectored()
1340 }
1341 #[inline]
1342 fn flush(&mut self) -> io::Result<()> {
1343 (&**self).flush()
1344 }
1345}
1346#[stable(feature = "io_traits_arc", since = "1.73.0")]
1347impl Seek for Arc<File> {
1348 fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
1349 (&**self).seek(pos)
1350 }
1351 fn stream_position(&mut self) -> io::Result<u64> {
1352 (&**self).stream_position()
1353 }
1354}
1355
1356impl OpenOptions {
1357 /// Creates a blank new set of options ready for configuration.
1358 ///
1359 /// All options are initially set to `false`.
1360 ///
1361 /// # Examples
1362 ///
1363 /// ```no_run
1364 /// use std::fs::OpenOptions;
1365 ///
1366 /// let mut options = OpenOptions::new();
1367 /// let file = options.read(true).open("foo.txt");
1368 /// ```
1369 #[cfg_attr(not(test), rustc_diagnostic_item = "open_options_new")]
1370 #[stable(feature = "rust1", since = "1.0.0")]
1371 #[must_use]
1372 pub fn new() -> Self {
1373 OpenOptions(fs_imp::OpenOptions::new())
1374 }
1375
1376 /// Sets the option for read access.
1377 ///
1378 /// This option, when true, will indicate that the file should be
1379 /// `read`-able if opened.
1380 ///
1381 /// # Examples
1382 ///
1383 /// ```no_run
1384 /// use std::fs::OpenOptions;
1385 ///
1386 /// let file = OpenOptions::new().read(true).open("foo.txt");
1387 /// ```
1388 #[stable(feature = "rust1", since = "1.0.0")]
1389 pub fn read(&mut self, read: bool) -> &mut Self {
1390 self.0.read(read);
1391 self
1392 }
1393
1394 /// Sets the option for write access.
1395 ///
1396 /// This option, when true, will indicate that the file should be
1397 /// `write`-able if opened.
1398 ///
1399 /// If the file already exists, any write calls on it will overwrite its
1400 /// contents, without truncating it.
1401 ///
1402 /// # Examples
1403 ///
1404 /// ```no_run
1405 /// use std::fs::OpenOptions;
1406 ///
1407 /// let file = OpenOptions::new().write(true).open("foo.txt");
1408 /// ```
1409 #[stable(feature = "rust1", since = "1.0.0")]
1410 pub fn write(&mut self, write: bool) -> &mut Self {
1411 self.0.write(write);
1412 self
1413 }
1414
1415 /// Sets the option for the append mode.
1416 ///
1417 /// This option, when true, means that writes will append to a file instead
1418 /// of overwriting previous contents.
1419 /// Note that setting `.write(true).append(true)` has the same effect as
1420 /// setting only `.append(true)`.
1421 ///
1422 /// Append mode guarantees that writes will be positioned at the current end of file,
1423 /// even when there are other processes or threads appending to the same file. This is
1424 /// unlike <code>[seek]\([SeekFrom]::[End]\(0))</code> followed by `write()`, which
1425 /// has a race between seeking and writing during which another writer can write, with
1426 /// our `write()` overwriting their data.
1427 ///
1428 /// Keep in mind that this does not necessarily guarantee that data appended by
1429 /// different processes or threads does not interleave. The amount of data accepted a
1430 /// single `write()` call depends on the operating system and file system. A
1431 /// successful `write()` is allowed to write only part of the given data, so even if
1432 /// you're careful to provide the whole message in a single call to `write()`, there
1433 /// is no guarantee that it will be written out in full. If you rely on the filesystem
1434 /// accepting the message in a single write, make sure that all data that belongs
1435 /// together is written in one operation. This can be done by concatenating strings
1436 /// before passing them to [`write()`].
1437 ///
1438 /// If a file is opened with both read and append access, beware that after
1439 /// opening, and after every write, the position for reading may be set at the
1440 /// end of the file. So, before writing, save the current position (using
1441 /// <code>[Seek]::[stream_position]</code>), and restore it before the next read.
1442 ///
1443 /// ## Note
1444 ///
1445 /// This function doesn't create the file if it doesn't exist. Use the
1446 /// [`OpenOptions::create`] method to do so.
1447 ///
1448 /// [`write()`]: Write::write "io::Write::write"
1449 /// [`flush()`]: Write::flush "io::Write::flush"
1450 /// [stream_position]: Seek::stream_position "io::Seek::stream_position"
1451 /// [seek]: Seek::seek "io::Seek::seek"
1452 /// [Current]: SeekFrom::Current "io::SeekFrom::Current"
1453 /// [End]: SeekFrom::End "io::SeekFrom::End"
1454 ///
1455 /// # Examples
1456 ///
1457 /// ```no_run
1458 /// use std::fs::OpenOptions;
1459 ///
1460 /// let file = OpenOptions::new().append(true).open("foo.txt");
1461 /// ```
1462 #[stable(feature = "rust1", since = "1.0.0")]
1463 pub fn append(&mut self, append: bool) -> &mut Self {
1464 self.0.append(append);
1465 self
1466 }
1467
1468 /// Sets the option for truncating a previous file.
1469 ///
1470 /// If a file is successfully opened with this option set to true, it will truncate
1471 /// the file to 0 length if it already exists.
1472 ///
1473 /// The file must be opened with write access for truncate to work.
1474 ///
1475 /// # Examples
1476 ///
1477 /// ```no_run
1478 /// use std::fs::OpenOptions;
1479 ///
1480 /// let file = OpenOptions::new().write(true).truncate(true).open("foo.txt");
1481 /// ```
1482 #[stable(feature = "rust1", since = "1.0.0")]
1483 pub fn truncate(&mut self, truncate: bool) -> &mut Self {
1484 self.0.truncate(truncate);
1485 self
1486 }
1487
1488 /// Sets the option to create a new file, or open it if it already exists.
1489 ///
1490 /// In order for the file to be created, [`OpenOptions::write`] or
1491 /// [`OpenOptions::append`] access must be used.
1492 ///
1493 /// See also [`std::fs::write()`][self::write] for a simple function to
1494 /// create a file with some given data.
1495 ///
1496 /// # Examples
1497 ///
1498 /// ```no_run
1499 /// use std::fs::OpenOptions;
1500 ///
1501 /// let file = OpenOptions::new().write(true).create(true).open("foo.txt");
1502 /// ```
1503 #[stable(feature = "rust1", since = "1.0.0")]
1504 pub fn create(&mut self, create: bool) -> &mut Self {
1505 self.0.create(create);
1506 self
1507 }
1508
1509 /// Sets the option to create a new file, failing if it already exists.
1510 ///
1511 /// No file is allowed to exist at the target location, also no (dangling) symlink. In this
1512 /// way, if the call succeeds, the file returned is guaranteed to be new.
1513 /// If a file exists at the target location, creating a new file will fail with [`AlreadyExists`]
1514 /// or another error based on the situation. See [`OpenOptions::open`] for a
1515 /// non-exhaustive list of likely errors.
1516 ///
1517 /// This option is useful because it is atomic. Otherwise between checking
1518 /// whether a file exists and creating a new one, the file may have been
1519 /// created by another process (a TOCTOU race condition / attack).
1520 ///
1521 /// If `.create_new(true)` is set, [`.create()`] and [`.truncate()`] are
1522 /// ignored.
1523 ///
1524 /// The file must be opened with write or append access in order to create
1525 /// a new file.
1526 ///
1527 /// [`.create()`]: OpenOptions::create
1528 /// [`.truncate()`]: OpenOptions::truncate
1529 /// [`AlreadyExists`]: io::ErrorKind::AlreadyExists
1530 ///
1531 /// # Examples
1532 ///
1533 /// ```no_run
1534 /// use std::fs::OpenOptions;
1535 ///
1536 /// let file = OpenOptions::new().write(true)
1537 /// .create_new(true)
1538 /// .open("foo.txt");
1539 /// ```
1540 #[stable(feature = "expand_open_options2", since = "1.9.0")]
1541 pub fn create_new(&mut self, create_new: bool) -> &mut Self {
1542 self.0.create_new(create_new);
1543 self
1544 }
1545
1546 /// Opens a file at `path` with the options specified by `self`.
1547 ///
1548 /// # Errors
1549 ///
1550 /// This function will return an error under a number of different
1551 /// circumstances. Some of these error conditions are listed here, together
1552 /// with their [`io::ErrorKind`]. The mapping to [`io::ErrorKind`]s is not
1553 /// part of the compatibility contract of the function.
1554 ///
1555 /// * [`NotFound`]: The specified file does not exist and neither `create`
1556 /// or `create_new` is set.
1557 /// * [`NotFound`]: One of the directory components of the file path does
1558 /// not exist.
1559 /// * [`PermissionDenied`]: The user lacks permission to get the specified
1560 /// access rights for the file.
1561 /// * [`PermissionDenied`]: The user lacks permission to open one of the
1562 /// directory components of the specified path.
1563 /// * [`AlreadyExists`]: `create_new` was specified and the file already
1564 /// exists.
1565 /// * [`InvalidInput`]: Invalid combinations of open options (truncate
1566 /// without write access, no access mode set, etc.).
1567 ///
1568 /// The following errors don't match any existing [`io::ErrorKind`] at the moment:
1569 /// * One of the directory components of the specified file path
1570 /// was not, in fact, a directory.
1571 /// * Filesystem-level errors: full disk, write permission
1572 /// requested on a read-only file system, exceeded disk quota, too many
1573 /// open files, too long filename, too many symbolic links in the
1574 /// specified path (Unix-like systems only), etc.
1575 ///
1576 /// # Examples
1577 ///
1578 /// ```no_run
1579 /// use std::fs::OpenOptions;
1580 ///
1581 /// let file = OpenOptions::new().read(true).open("foo.txt");
1582 /// ```
1583 ///
1584 /// [`AlreadyExists`]: io::ErrorKind::AlreadyExists
1585 /// [`InvalidInput`]: io::ErrorKind::InvalidInput
1586 /// [`NotFound`]: io::ErrorKind::NotFound
1587 /// [`PermissionDenied`]: io::ErrorKind::PermissionDenied
1588 #[stable(feature = "rust1", since = "1.0.0")]
1589 pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
1590 self._open(path.as_ref())
1591 }
1592
1593 fn _open(&self, path: &Path) -> io::Result<File> {
1594 fs_imp::File::open(path, &self.0).map(|inner| File { inner })
1595 }
1596}
1597
1598impl AsInner<fs_imp::OpenOptions> for OpenOptions {
1599 #[inline]
1600 fn as_inner(&self) -> &fs_imp::OpenOptions {
1601 &self.0
1602 }
1603}
1604
1605impl AsInnerMut<fs_imp::OpenOptions> for OpenOptions {
1606 #[inline]
1607 fn as_inner_mut(&mut self) -> &mut fs_imp::OpenOptions {
1608 &mut self.0
1609 }
1610}
1611
1612impl Metadata {
1613 /// Returns the file type for this metadata.
1614 ///
1615 /// # Examples
1616 ///
1617 /// ```no_run
1618 /// fn main() -> std::io::Result<()> {
1619 /// use std::fs;
1620 ///
1621 /// let metadata = fs::metadata("foo.txt")?;
1622 ///
1623 /// println!("{:?}", metadata.file_type());
1624 /// Ok(())
1625 /// }
1626 /// ```
1627 #[must_use]
1628 #[stable(feature = "file_type", since = "1.1.0")]
1629 pub fn file_type(&self) -> FileType {
1630 FileType(self.0.file_type())
1631 }
1632
1633 /// Returns `true` if this metadata is for a directory. The
1634 /// result is mutually exclusive to the result of
1635 /// [`Metadata::is_file`], and will be false for symlink metadata
1636 /// obtained from [`symlink_metadata`].
1637 ///
1638 /// # Examples
1639 ///
1640 /// ```no_run
1641 /// fn main() -> std::io::Result<()> {
1642 /// use std::fs;
1643 ///
1644 /// let metadata = fs::metadata("foo.txt")?;
1645 ///
1646 /// assert!(!metadata.is_dir());
1647 /// Ok(())
1648 /// }
1649 /// ```
1650 #[must_use]
1651 #[stable(feature = "rust1", since = "1.0.0")]
1652 pub fn is_dir(&self) -> bool {
1653 self.file_type().is_dir()
1654 }
1655
1656 /// Returns `true` if this metadata is for a regular file. The
1657 /// result is mutually exclusive to the result of
1658 /// [`Metadata::is_dir`], and will be false for symlink metadata
1659 /// obtained from [`symlink_metadata`].
1660 ///
1661 /// When the goal is simply to read from (or write to) the source, the most
1662 /// reliable way to test the source can be read (or written to) is to open
1663 /// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
1664 /// a Unix-like system for example. See [`File::open`] or
1665 /// [`OpenOptions::open`] for more information.
1666 ///
1667 /// # Examples
1668 ///
1669 /// ```no_run
1670 /// use std::fs;
1671 ///
1672 /// fn main() -> std::io::Result<()> {
1673 /// let metadata = fs::metadata("foo.txt")?;
1674 ///
1675 /// assert!(metadata.is_file());
1676 /// Ok(())
1677 /// }
1678 /// ```
1679 #[must_use]
1680 #[stable(feature = "rust1", since = "1.0.0")]
1681 pub fn is_file(&self) -> bool {
1682 self.file_type().is_file()
1683 }
1684
1685 /// Returns `true` if this metadata is for a symbolic link.
1686 ///
1687 /// # Examples
1688 ///
1689 #[cfg_attr(unix, doc = "```no_run")]
1690 #[cfg_attr(not(unix), doc = "```ignore")]
1691 /// use std::fs;
1692 /// use std::path::Path;
1693 /// use std::os::unix::fs::symlink;
1694 ///
1695 /// fn main() -> std::io::Result<()> {
1696 /// let link_path = Path::new("link");
1697 /// symlink("/origin_does_not_exist/", link_path)?;
1698 ///
1699 /// let metadata = fs::symlink_metadata(link_path)?;
1700 ///
1701 /// assert!(metadata.is_symlink());
1702 /// Ok(())
1703 /// }
1704 /// ```
1705 #[must_use]
1706 #[stable(feature = "is_symlink", since = "1.58.0")]
1707 pub fn is_symlink(&self) -> bool {
1708 self.file_type().is_symlink()
1709 }
1710
1711 /// Returns the size of the file, in bytes, this metadata is for.
1712 ///
1713 /// # Examples
1714 ///
1715 /// ```no_run
1716 /// use std::fs;
1717 ///
1718 /// fn main() -> std::io::Result<()> {
1719 /// let metadata = fs::metadata("foo.txt")?;
1720 ///
1721 /// assert_eq!(0, metadata.len());
1722 /// Ok(())
1723 /// }
1724 /// ```
1725 #[must_use]
1726 #[stable(feature = "rust1", since = "1.0.0")]
1727 pub fn len(&self) -> u64 {
1728 self.0.size()
1729 }
1730
1731 /// Returns the permissions of the file this metadata is for.
1732 ///
1733 /// # Examples
1734 ///
1735 /// ```no_run
1736 /// use std::fs;
1737 ///
1738 /// fn main() -> std::io::Result<()> {
1739 /// let metadata = fs::metadata("foo.txt")?;
1740 ///
1741 /// assert!(!metadata.permissions().readonly());
1742 /// Ok(())
1743 /// }
1744 /// ```
1745 #[must_use]
1746 #[stable(feature = "rust1", since = "1.0.0")]
1747 pub fn permissions(&self) -> Permissions {
1748 Permissions(self.0.perm())
1749 }
1750
1751 /// Returns the last modification time listed in this metadata.
1752 ///
1753 /// The returned value corresponds to the `mtime` field of `stat` on Unix
1754 /// platforms and the `ftLastWriteTime` field on Windows platforms.
1755 ///
1756 /// # Errors
1757 ///
1758 /// This field might not be available on all platforms, and will return an
1759 /// `Err` on platforms where it is not available.
1760 ///
1761 /// # Examples
1762 ///
1763 /// ```no_run
1764 /// use std::fs;
1765 ///
1766 /// fn main() -> std::io::Result<()> {
1767 /// let metadata = fs::metadata("foo.txt")?;
1768 ///
1769 /// if let Ok(time) = metadata.modified() {
1770 /// println!("{time:?}");
1771 /// } else {
1772 /// println!("Not supported on this platform");
1773 /// }
1774 /// Ok(())
1775 /// }
1776 /// ```
1777 #[doc(alias = "mtime", alias = "ftLastWriteTime")]
1778 #[stable(feature = "fs_time", since = "1.10.0")]
1779 pub fn modified(&self) -> io::Result<SystemTime> {
1780 self.0.modified().map(FromInner::from_inner)
1781 }
1782
1783 /// Returns the last access time of this metadata.
1784 ///
1785 /// The returned value corresponds to the `atime` field of `stat` on Unix
1786 /// platforms and the `ftLastAccessTime` field on Windows platforms.
1787 ///
1788 /// Note that not all platforms will keep this field update in a file's
1789 /// metadata, for example Windows has an option to disable updating this
1790 /// time when files are accessed and Linux similarly has `noatime`.
1791 ///
1792 /// # Errors
1793 ///
1794 /// This field might not be available on all platforms, and will return an
1795 /// `Err` on platforms where it is not available.
1796 ///
1797 /// # Examples
1798 ///
1799 /// ```no_run
1800 /// use std::fs;
1801 ///
1802 /// fn main() -> std::io::Result<()> {
1803 /// let metadata = fs::metadata("foo.txt")?;
1804 ///
1805 /// if let Ok(time) = metadata.accessed() {
1806 /// println!("{time:?}");
1807 /// } else {
1808 /// println!("Not supported on this platform");
1809 /// }
1810 /// Ok(())
1811 /// }
1812 /// ```
1813 #[doc(alias = "atime", alias = "ftLastAccessTime")]
1814 #[stable(feature = "fs_time", since = "1.10.0")]
1815 pub fn accessed(&self) -> io::Result<SystemTime> {
1816 self.0.accessed().map(FromInner::from_inner)
1817 }
1818
1819 /// Returns the creation time listed in this metadata.
1820 ///
1821 /// The returned value corresponds to the `btime` field of `statx` on
1822 /// Linux kernel starting from to 4.11, the `birthtime` field of `stat` on other
1823 /// Unix platforms, and the `ftCreationTime` field on Windows platforms.
1824 ///
1825 /// # Errors
1826 ///
1827 /// This field might not be available on all platforms, and will return an
1828 /// `Err` on platforms or filesystems where it is not available.
1829 ///
1830 /// # Examples
1831 ///
1832 /// ```no_run
1833 /// use std::fs;
1834 ///
1835 /// fn main() -> std::io::Result<()> {
1836 /// let metadata = fs::metadata("foo.txt")?;
1837 ///
1838 /// if let Ok(time) = metadata.created() {
1839 /// println!("{time:?}");
1840 /// } else {
1841 /// println!("Not supported on this platform or filesystem");
1842 /// }
1843 /// Ok(())
1844 /// }
1845 /// ```
1846 #[doc(alias = "btime", alias = "birthtime", alias = "ftCreationTime")]
1847 #[stable(feature = "fs_time", since = "1.10.0")]
1848 pub fn created(&self) -> io::Result<SystemTime> {
1849 self.0.created().map(FromInner::from_inner)
1850 }
1851}
1852
1853#[stable(feature = "std_debug", since = "1.16.0")]
1854impl fmt::Debug for Metadata {
1855 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
1856 let mut debug: DebugStruct<'_, '_> = f.debug_struct(name:"Metadata");
1857 debug.field(name:"file_type", &self.file_type());
1858 debug.field(name:"permissions", &self.permissions());
1859 debug.field(name:"len", &self.len());
1860 if let Ok(modified: SystemTime) = self.modified() {
1861 debug.field(name:"modified", &modified);
1862 }
1863 if let Ok(accessed: SystemTime) = self.accessed() {
1864 debug.field(name:"accessed", &accessed);
1865 }
1866 if let Ok(created: SystemTime) = self.created() {
1867 debug.field(name:"created", &created);
1868 }
1869 debug.finish_non_exhaustive()
1870 }
1871}
1872
1873impl AsInner<fs_imp::FileAttr> for Metadata {
1874 #[inline]
1875 fn as_inner(&self) -> &fs_imp::FileAttr {
1876 &self.0
1877 }
1878}
1879
1880impl FromInner<fs_imp::FileAttr> for Metadata {
1881 fn from_inner(attr: fs_imp::FileAttr) -> Metadata {
1882 Metadata(attr)
1883 }
1884}
1885
1886impl FileTimes {
1887 /// Creates a new `FileTimes` with no times set.
1888 ///
1889 /// Using the resulting `FileTimes` in [`File::set_times`] will not modify any timestamps.
1890 #[stable(feature = "file_set_times", since = "1.75.0")]
1891 pub fn new() -> Self {
1892 Self::default()
1893 }
1894
1895 /// Set the last access time of a file.
1896 #[stable(feature = "file_set_times", since = "1.75.0")]
1897 pub fn set_accessed(mut self, t: SystemTime) -> Self {
1898 self.0.set_accessed(t.into_inner());
1899 self
1900 }
1901
1902 /// Set the last modified time of a file.
1903 #[stable(feature = "file_set_times", since = "1.75.0")]
1904 pub fn set_modified(mut self, t: SystemTime) -> Self {
1905 self.0.set_modified(t.into_inner());
1906 self
1907 }
1908}
1909
1910impl AsInnerMut<fs_imp::FileTimes> for FileTimes {
1911 fn as_inner_mut(&mut self) -> &mut fs_imp::FileTimes {
1912 &mut self.0
1913 }
1914}
1915
1916// For implementing OS extension traits in `std::os`
1917#[stable(feature = "file_set_times", since = "1.75.0")]
1918impl Sealed for FileTimes {}
1919
1920impl Permissions {
1921 /// Returns `true` if these permissions describe a readonly (unwritable) file.
1922 ///
1923 /// # Note
1924 ///
1925 /// This function does not take Access Control Lists (ACLs), Unix group
1926 /// membership and other nuances into account.
1927 /// Therefore the return value of this function cannot be relied upon
1928 /// to predict whether attempts to read or write the file will actually succeed.
1929 ///
1930 /// # Windows
1931 ///
1932 /// On Windows this returns [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
1933 /// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
1934 /// but the user may still have permission to change this flag. If
1935 /// `FILE_ATTRIBUTE_READONLY` is *not* set then writes may still fail due
1936 /// to lack of write permission.
1937 /// The behavior of this attribute for directories depends on the Windows
1938 /// version.
1939 ///
1940 /// # Unix (including macOS)
1941 ///
1942 /// On Unix-based platforms this checks if *any* of the owner, group or others
1943 /// write permission bits are set. It does not consider anything else, including:
1944 ///
1945 /// * Whether the current user is in the file's assigned group.
1946 /// * Permissions granted by ACL.
1947 /// * That `root` user can write to files that do not have any write bits set.
1948 /// * Writable files on a filesystem that is mounted read-only.
1949 ///
1950 /// The [`PermissionsExt`] trait gives direct access to the permission bits but
1951 /// also does not read ACLs.
1952 ///
1953 /// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
1954 ///
1955 /// # Examples
1956 ///
1957 /// ```no_run
1958 /// use std::fs::File;
1959 ///
1960 /// fn main() -> std::io::Result<()> {
1961 /// let mut f = File::create("foo.txt")?;
1962 /// let metadata = f.metadata()?;
1963 ///
1964 /// assert_eq!(false, metadata.permissions().readonly());
1965 /// Ok(())
1966 /// }
1967 /// ```
1968 #[must_use = "call `set_readonly` to modify the readonly flag"]
1969 #[stable(feature = "rust1", since = "1.0.0")]
1970 pub fn readonly(&self) -> bool {
1971 self.0.readonly()
1972 }
1973
1974 /// Modifies the readonly flag for this set of permissions. If the
1975 /// `readonly` argument is `true`, using the resulting `Permission` will
1976 /// update file permissions to forbid writing. Conversely, if it's `false`,
1977 /// using the resulting `Permission` will update file permissions to allow
1978 /// writing.
1979 ///
1980 /// This operation does **not** modify the files attributes. This only
1981 /// changes the in-memory value of these attributes for this `Permissions`
1982 /// instance. To modify the files attributes use the [`set_permissions`]
1983 /// function which commits these attribute changes to the file.
1984 ///
1985 /// # Note
1986 ///
1987 /// `set_readonly(false)` makes the file *world-writable* on Unix.
1988 /// You can use the [`PermissionsExt`] trait on Unix to avoid this issue.
1989 ///
1990 /// It also does not take Access Control Lists (ACLs) or Unix group
1991 /// membership into account.
1992 ///
1993 /// # Windows
1994 ///
1995 /// On Windows this sets or clears [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
1996 /// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
1997 /// but the user may still have permission to change this flag. If
1998 /// `FILE_ATTRIBUTE_READONLY` is *not* set then the write may still fail if
1999 /// the user does not have permission to write to the file.
2000 ///
2001 /// In Windows 7 and earlier this attribute prevents deleting empty
2002 /// directories. It does not prevent modifying the directory contents.
2003 /// On later versions of Windows this attribute is ignored for directories.
2004 ///
2005 /// # Unix (including macOS)
2006 ///
2007 /// On Unix-based platforms this sets or clears the write access bit for
2008 /// the owner, group *and* others, equivalent to `chmod a+w <file>`
2009 /// or `chmod a-w <file>` respectively. The latter will grant write access
2010 /// to all users! You can use the [`PermissionsExt`] trait on Unix
2011 /// to avoid this issue.
2012 ///
2013 /// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
2014 ///
2015 /// # Examples
2016 ///
2017 /// ```no_run
2018 /// use std::fs::File;
2019 ///
2020 /// fn main() -> std::io::Result<()> {
2021 /// let f = File::create("foo.txt")?;
2022 /// let metadata = f.metadata()?;
2023 /// let mut permissions = metadata.permissions();
2024 ///
2025 /// permissions.set_readonly(true);
2026 ///
2027 /// // filesystem doesn't change, only the in memory state of the
2028 /// // readonly permission
2029 /// assert_eq!(false, metadata.permissions().readonly());
2030 ///
2031 /// // just this particular `permissions`.
2032 /// assert_eq!(true, permissions.readonly());
2033 /// Ok(())
2034 /// }
2035 /// ```
2036 #[stable(feature = "rust1", since = "1.0.0")]
2037 pub fn set_readonly(&mut self, readonly: bool) {
2038 self.0.set_readonly(readonly)
2039 }
2040}
2041
2042impl FileType {
2043 /// Tests whether this file type represents a directory. The
2044 /// result is mutually exclusive to the results of
2045 /// [`is_file`] and [`is_symlink`]; only zero or one of these
2046 /// tests may pass.
2047 ///
2048 /// [`is_file`]: FileType::is_file
2049 /// [`is_symlink`]: FileType::is_symlink
2050 ///
2051 /// # Examples
2052 ///
2053 /// ```no_run
2054 /// fn main() -> std::io::Result<()> {
2055 /// use std::fs;
2056 ///
2057 /// let metadata = fs::metadata("foo.txt")?;
2058 /// let file_type = metadata.file_type();
2059 ///
2060 /// assert_eq!(file_type.is_dir(), false);
2061 /// Ok(())
2062 /// }
2063 /// ```
2064 #[must_use]
2065 #[stable(feature = "file_type", since = "1.1.0")]
2066 pub fn is_dir(&self) -> bool {
2067 self.0.is_dir()
2068 }
2069
2070 /// Tests whether this file type represents a regular file.
2071 /// The result is mutually exclusive to the results of
2072 /// [`is_dir`] and [`is_symlink`]; only zero or one of these
2073 /// tests may pass.
2074 ///
2075 /// When the goal is simply to read from (or write to) the source, the most
2076 /// reliable way to test the source can be read (or written to) is to open
2077 /// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
2078 /// a Unix-like system for example. See [`File::open`] or
2079 /// [`OpenOptions::open`] for more information.
2080 ///
2081 /// [`is_dir`]: FileType::is_dir
2082 /// [`is_symlink`]: FileType::is_symlink
2083 ///
2084 /// # Examples
2085 ///
2086 /// ```no_run
2087 /// fn main() -> std::io::Result<()> {
2088 /// use std::fs;
2089 ///
2090 /// let metadata = fs::metadata("foo.txt")?;
2091 /// let file_type = metadata.file_type();
2092 ///
2093 /// assert_eq!(file_type.is_file(), true);
2094 /// Ok(())
2095 /// }
2096 /// ```
2097 #[must_use]
2098 #[stable(feature = "file_type", since = "1.1.0")]
2099 pub fn is_file(&self) -> bool {
2100 self.0.is_file()
2101 }
2102
2103 /// Tests whether this file type represents a symbolic link.
2104 /// The result is mutually exclusive to the results of
2105 /// [`is_dir`] and [`is_file`]; only zero or one of these
2106 /// tests may pass.
2107 ///
2108 /// The underlying [`Metadata`] struct needs to be retrieved
2109 /// with the [`fs::symlink_metadata`] function and not the
2110 /// [`fs::metadata`] function. The [`fs::metadata`] function
2111 /// follows symbolic links, so [`is_symlink`] would always
2112 /// return `false` for the target file.
2113 ///
2114 /// [`fs::metadata`]: metadata
2115 /// [`fs::symlink_metadata`]: symlink_metadata
2116 /// [`is_dir`]: FileType::is_dir
2117 /// [`is_file`]: FileType::is_file
2118 /// [`is_symlink`]: FileType::is_symlink
2119 ///
2120 /// # Examples
2121 ///
2122 /// ```no_run
2123 /// use std::fs;
2124 ///
2125 /// fn main() -> std::io::Result<()> {
2126 /// let metadata = fs::symlink_metadata("foo.txt")?;
2127 /// let file_type = metadata.file_type();
2128 ///
2129 /// assert_eq!(file_type.is_symlink(), false);
2130 /// Ok(())
2131 /// }
2132 /// ```
2133 #[must_use]
2134 #[stable(feature = "file_type", since = "1.1.0")]
2135 pub fn is_symlink(&self) -> bool {
2136 self.0.is_symlink()
2137 }
2138}
2139
2140#[stable(feature = "std_debug", since = "1.16.0")]
2141impl fmt::Debug for FileType {
2142 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2143 f&mut DebugStruct<'_, '_>.debug_struct("FileType")
2144 .field("is_file", &self.is_file())
2145 .field("is_dir", &self.is_dir())
2146 .field(name:"is_symlink", &self.is_symlink())
2147 .finish_non_exhaustive()
2148 }
2149}
2150
2151impl AsInner<fs_imp::FileType> for FileType {
2152 #[inline]
2153 fn as_inner(&self) -> &fs_imp::FileType {
2154 &self.0
2155 }
2156}
2157
2158impl FromInner<fs_imp::FilePermissions> for Permissions {
2159 fn from_inner(f: fs_imp::FilePermissions) -> Permissions {
2160 Permissions(f)
2161 }
2162}
2163
2164impl AsInner<fs_imp::FilePermissions> for Permissions {
2165 #[inline]
2166 fn as_inner(&self) -> &fs_imp::FilePermissions {
2167 &self.0
2168 }
2169}
2170
2171#[stable(feature = "rust1", since = "1.0.0")]
2172impl Iterator for ReadDir {
2173 type Item = io::Result<DirEntry>;
2174
2175 fn next(&mut self) -> Option<io::Result<DirEntry>> {
2176 self.0.next().map(|entry: Result| entry.map(op:DirEntry))
2177 }
2178}
2179
2180impl DirEntry {
2181 /// Returns the full path to the file that this entry represents.
2182 ///
2183 /// The full path is created by joining the original path to `read_dir`
2184 /// with the filename of this entry.
2185 ///
2186 /// # Examples
2187 ///
2188 /// ```no_run
2189 /// use std::fs;
2190 ///
2191 /// fn main() -> std::io::Result<()> {
2192 /// for entry in fs::read_dir(".")? {
2193 /// let dir = entry?;
2194 /// println!("{:?}", dir.path());
2195 /// }
2196 /// Ok(())
2197 /// }
2198 /// ```
2199 ///
2200 /// This prints output like:
2201 ///
2202 /// ```text
2203 /// "./whatever.txt"
2204 /// "./foo.html"
2205 /// "./hello_world.rs"
2206 /// ```
2207 ///
2208 /// The exact text, of course, depends on what files you have in `.`.
2209 #[must_use]
2210 #[stable(feature = "rust1", since = "1.0.0")]
2211 pub fn path(&self) -> PathBuf {
2212 self.0.path()
2213 }
2214
2215 /// Returns the metadata for the file that this entry points at.
2216 ///
2217 /// This function will not traverse symlinks if this entry points at a
2218 /// symlink. To traverse symlinks use [`fs::metadata`] or [`fs::File::metadata`].
2219 ///
2220 /// [`fs::metadata`]: metadata
2221 /// [`fs::File::metadata`]: File::metadata
2222 ///
2223 /// # Platform-specific behavior
2224 ///
2225 /// On Windows this function is cheap to call (no extra system calls
2226 /// needed), but on Unix platforms this function is the equivalent of
2227 /// calling `symlink_metadata` on the path.
2228 ///
2229 /// # Examples
2230 ///
2231 /// ```
2232 /// use std::fs;
2233 ///
2234 /// if let Ok(entries) = fs::read_dir(".") {
2235 /// for entry in entries {
2236 /// if let Ok(entry) = entry {
2237 /// // Here, `entry` is a `DirEntry`.
2238 /// if let Ok(metadata) = entry.metadata() {
2239 /// // Now let's show our entry's permissions!
2240 /// println!("{:?}: {:?}", entry.path(), metadata.permissions());
2241 /// } else {
2242 /// println!("Couldn't get metadata for {:?}", entry.path());
2243 /// }
2244 /// }
2245 /// }
2246 /// }
2247 /// ```
2248 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
2249 pub fn metadata(&self) -> io::Result<Metadata> {
2250 self.0.metadata().map(Metadata)
2251 }
2252
2253 /// Returns the file type for the file that this entry points at.
2254 ///
2255 /// This function will not traverse symlinks if this entry points at a
2256 /// symlink.
2257 ///
2258 /// # Platform-specific behavior
2259 ///
2260 /// On Windows and most Unix platforms this function is free (no extra
2261 /// system calls needed), but some Unix platforms may require the equivalent
2262 /// call to `symlink_metadata` to learn about the target file type.
2263 ///
2264 /// # Examples
2265 ///
2266 /// ```
2267 /// use std::fs;
2268 ///
2269 /// if let Ok(entries) = fs::read_dir(".") {
2270 /// for entry in entries {
2271 /// if let Ok(entry) = entry {
2272 /// // Here, `entry` is a `DirEntry`.
2273 /// if let Ok(file_type) = entry.file_type() {
2274 /// // Now let's show our entry's file type!
2275 /// println!("{:?}: {:?}", entry.path(), file_type);
2276 /// } else {
2277 /// println!("Couldn't get file type for {:?}", entry.path());
2278 /// }
2279 /// }
2280 /// }
2281 /// }
2282 /// ```
2283 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
2284 pub fn file_type(&self) -> io::Result<FileType> {
2285 self.0.file_type().map(FileType)
2286 }
2287
2288 /// Returns the file name of this directory entry without any
2289 /// leading path component(s).
2290 ///
2291 /// As an example,
2292 /// the output of the function will result in "foo" for all the following paths:
2293 /// - "./foo"
2294 /// - "/the/foo"
2295 /// - "../../foo"
2296 ///
2297 /// # Examples
2298 ///
2299 /// ```
2300 /// use std::fs;
2301 ///
2302 /// if let Ok(entries) = fs::read_dir(".") {
2303 /// for entry in entries {
2304 /// if let Ok(entry) = entry {
2305 /// // Here, `entry` is a `DirEntry`.
2306 /// println!("{:?}", entry.file_name());
2307 /// }
2308 /// }
2309 /// }
2310 /// ```
2311 #[must_use]
2312 #[stable(feature = "dir_entry_ext", since = "1.1.0")]
2313 pub fn file_name(&self) -> OsString {
2314 self.0.file_name()
2315 }
2316}
2317
2318#[stable(feature = "dir_entry_debug", since = "1.13.0")]
2319impl fmt::Debug for DirEntry {
2320 fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
2321 f.debug_tuple(name:"DirEntry").field(&self.path()).finish()
2322 }
2323}
2324
2325impl AsInner<fs_imp::DirEntry> for DirEntry {
2326 #[inline]
2327 fn as_inner(&self) -> &fs_imp::DirEntry {
2328 &self.0
2329 }
2330}
2331
2332/// Removes a file from the filesystem.
2333///
2334/// Note that there is no
2335/// guarantee that the file is immediately deleted (e.g., depending on
2336/// platform, other open file descriptors may prevent immediate removal).
2337///
2338/// # Platform-specific behavior
2339///
2340/// This function currently corresponds to the `unlink` function on Unix.
2341/// On Windows, `DeleteFile` is used or `CreateFileW` and `SetInformationByHandle` for readonly files.
2342/// Note that, this [may change in the future][changes].
2343///
2344/// [changes]: io#platform-specific-behavior
2345///
2346/// # Errors
2347///
2348/// This function will return an error in the following situations, but is not
2349/// limited to just these cases:
2350///
2351/// * `path` points to a directory.
2352/// * The file doesn't exist.
2353/// * The user lacks permissions to remove the file.
2354///
2355/// This function will only ever return an error of kind `NotFound` if the given
2356/// path does not exist. Note that the inverse is not true,
2357/// ie. if a path does not exist, its removal may fail for a number of reasons,
2358/// such as insufficient permissions.
2359///
2360/// # Examples
2361///
2362/// ```no_run
2363/// use std::fs;
2364///
2365/// fn main() -> std::io::Result<()> {
2366/// fs::remove_file("a.txt")?;
2367/// Ok(())
2368/// }
2369/// ```
2370#[doc(alias = "rm", alias = "unlink", alias = "DeleteFile")]
2371#[stable(feature = "rust1", since = "1.0.0")]
2372pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
2373 fs_imp::unlink(path.as_ref())
2374}
2375
2376/// Given a path, queries the file system to get information about a file,
2377/// directory, etc.
2378///
2379/// This function will traverse symbolic links to query information about the
2380/// destination file.
2381///
2382/// # Platform-specific behavior
2383///
2384/// This function currently corresponds to the `stat` function on Unix
2385/// and the `GetFileInformationByHandle` function on Windows.
2386/// Note that, this [may change in the future][changes].
2387///
2388/// [changes]: io#platform-specific-behavior
2389///
2390/// # Errors
2391///
2392/// This function will return an error in the following situations, but is not
2393/// limited to just these cases:
2394///
2395/// * The user lacks permissions to perform `metadata` call on `path`.
2396/// * `path` does not exist.
2397///
2398/// # Examples
2399///
2400/// ```rust,no_run
2401/// use std::fs;
2402///
2403/// fn main() -> std::io::Result<()> {
2404/// let attr = fs::metadata("/some/file/path.txt")?;
2405/// // inspect attr ...
2406/// Ok(())
2407/// }
2408/// ```
2409#[doc(alias = "stat")]
2410#[stable(feature = "rust1", since = "1.0.0")]
2411pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
2412 fs_imp::stat(path.as_ref()).map(op:Metadata)
2413}
2414
2415/// Queries the metadata about a file without following symlinks.
2416///
2417/// # Platform-specific behavior
2418///
2419/// This function currently corresponds to the `lstat` function on Unix
2420/// and the `GetFileInformationByHandle` function on Windows.
2421/// Note that, this [may change in the future][changes].
2422///
2423/// [changes]: io#platform-specific-behavior
2424///
2425/// # Errors
2426///
2427/// This function will return an error in the following situations, but is not
2428/// limited to just these cases:
2429///
2430/// * The user lacks permissions to perform `metadata` call on `path`.
2431/// * `path` does not exist.
2432///
2433/// # Examples
2434///
2435/// ```rust,no_run
2436/// use std::fs;
2437///
2438/// fn main() -> std::io::Result<()> {
2439/// let attr = fs::symlink_metadata("/some/file/path.txt")?;
2440/// // inspect attr ...
2441/// Ok(())
2442/// }
2443/// ```
2444#[doc(alias = "lstat")]
2445#[stable(feature = "symlink_metadata", since = "1.1.0")]
2446pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
2447 fs_imp::lstat(path.as_ref()).map(op:Metadata)
2448}
2449
2450/// Renames a file or directory to a new name, replacing the original file if
2451/// `to` already exists.
2452///
2453/// This will not work if the new name is on a different mount point.
2454///
2455/// # Platform-specific behavior
2456///
2457/// This function currently corresponds to the `rename` function on Unix
2458/// and the `MoveFileExW` or `SetFileInformationByHandle` function on Windows.
2459///
2460/// Because of this, the behavior when both `from` and `to` exist differs. On
2461/// Unix, if `from` is a directory, `to` must also be an (empty) directory. If
2462/// `from` is not a directory, `to` must also be not a directory. The behavior
2463/// on Windows is the same on Windows 10 1607 and higher if `FileRenameInfoEx`
2464/// is supported by the filesystem; otherwise, `from` can be anything, but
2465/// `to` must *not* be a directory.
2466///
2467/// Note that, this [may change in the future][changes].
2468///
2469/// [changes]: io#platform-specific-behavior
2470///
2471/// # Errors
2472///
2473/// This function will return an error in the following situations, but is not
2474/// limited to just these cases:
2475///
2476/// * `from` does not exist.
2477/// * The user lacks permissions to view contents.
2478/// * `from` and `to` are on separate filesystems.
2479///
2480/// # Examples
2481///
2482/// ```no_run
2483/// use std::fs;
2484///
2485/// fn main() -> std::io::Result<()> {
2486/// fs::rename("a.txt", "b.txt")?; // Rename a.txt to b.txt
2487/// Ok(())
2488/// }
2489/// ```
2490#[doc(alias = "mv", alias = "MoveFile", alias = "MoveFileEx")]
2491#[stable(feature = "rust1", since = "1.0.0")]
2492pub fn rename<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<()> {
2493 fs_imp::rename(old:from.as_ref(), new:to.as_ref())
2494}
2495
2496/// Copies the contents of one file to another. This function will also
2497/// copy the permission bits of the original file to the destination file.
2498///
2499/// This function will **overwrite** the contents of `to`.
2500///
2501/// Note that if `from` and `to` both point to the same file, then the file
2502/// will likely get truncated by this operation.
2503///
2504/// On success, the total number of bytes copied is returned and it is equal to
2505/// the length of the `to` file as reported by `metadata`.
2506///
2507/// If you want to copy the contents of one file to another and you’re
2508/// working with [`File`]s, see the [`io::copy`](io::copy()) function.
2509///
2510/// # Platform-specific behavior
2511///
2512/// This function currently corresponds to the `open` function in Unix
2513/// with `O_RDONLY` for `from` and `O_WRONLY`, `O_CREAT`, and `O_TRUNC` for `to`.
2514/// `O_CLOEXEC` is set for returned file descriptors.
2515///
2516/// On Linux (including Android), this function attempts to use `copy_file_range(2)`,
2517/// and falls back to reading and writing if that is not possible.
2518///
2519/// On Windows, this function currently corresponds to `CopyFileEx`. Alternate
2520/// NTFS streams are copied but only the size of the main stream is returned by
2521/// this function.
2522///
2523/// On MacOS, this function corresponds to `fclonefileat` and `fcopyfile`.
2524///
2525/// Note that platform-specific behavior [may change in the future][changes].
2526///
2527/// [changes]: io#platform-specific-behavior
2528///
2529/// # Errors
2530///
2531/// This function will return an error in the following situations, but is not
2532/// limited to just these cases:
2533///
2534/// * `from` is neither a regular file nor a symlink to a regular file.
2535/// * `from` does not exist.
2536/// * The current process does not have the permission rights to read
2537/// `from` or write `to`.
2538/// * The parent directory of `to` doesn't exist.
2539///
2540/// # Examples
2541///
2542/// ```no_run
2543/// use std::fs;
2544///
2545/// fn main() -> std::io::Result<()> {
2546/// fs::copy("foo.txt", "bar.txt")?; // Copy foo.txt to bar.txt
2547/// Ok(())
2548/// }
2549/// ```
2550#[doc(alias = "cp")]
2551#[doc(alias = "CopyFile", alias = "CopyFileEx")]
2552#[doc(alias = "fclonefileat", alias = "fcopyfile")]
2553#[stable(feature = "rust1", since = "1.0.0")]
2554pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<u64> {
2555 fs_imp::copy(from.as_ref(), to.as_ref())
2556}
2557
2558/// Creates a new hard link on the filesystem.
2559///
2560/// The `link` path will be a link pointing to the `original` path. Note that
2561/// systems often require these two paths to both be located on the same
2562/// filesystem.
2563///
2564/// If `original` names a symbolic link, it is platform-specific whether the
2565/// symbolic link is followed. On platforms where it's possible to not follow
2566/// it, it is not followed, and the created hard link points to the symbolic
2567/// link itself.
2568///
2569/// # Platform-specific behavior
2570///
2571/// This function currently corresponds the `CreateHardLink` function on Windows.
2572/// On most Unix systems, it corresponds to the `linkat` function with no flags.
2573/// On Android, VxWorks, and Redox, it instead corresponds to the `link` function.
2574/// On MacOS, it uses the `linkat` function if it is available, but on very old
2575/// systems where `linkat` is not available, `link` is selected at runtime instead.
2576/// Note that, this [may change in the future][changes].
2577///
2578/// [changes]: io#platform-specific-behavior
2579///
2580/// # Errors
2581///
2582/// This function will return an error in the following situations, but is not
2583/// limited to just these cases:
2584///
2585/// * The `original` path is not a file or doesn't exist.
2586/// * The 'link' path already exists.
2587///
2588/// # Examples
2589///
2590/// ```no_run
2591/// use std::fs;
2592///
2593/// fn main() -> std::io::Result<()> {
2594/// fs::hard_link("a.txt", "b.txt")?; // Hard link a.txt to b.txt
2595/// Ok(())
2596/// }
2597/// ```
2598#[doc(alias = "CreateHardLink", alias = "linkat")]
2599#[stable(feature = "rust1", since = "1.0.0")]
2600pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
2601 fs_imp::link(original.as_ref(), link.as_ref())
2602}
2603
2604/// Creates a new symbolic link on the filesystem.
2605///
2606/// The `link` path will be a symbolic link pointing to the `original` path.
2607/// On Windows, this will be a file symlink, not a directory symlink;
2608/// for this reason, the platform-specific [`std::os::unix::fs::symlink`]
2609/// and [`std::os::windows::fs::symlink_file`] or [`symlink_dir`] should be
2610/// used instead to make the intent explicit.
2611///
2612/// [`std::os::unix::fs::symlink`]: crate::os::unix::fs::symlink
2613/// [`std::os::windows::fs::symlink_file`]: crate::os::windows::fs::symlink_file
2614/// [`symlink_dir`]: crate::os::windows::fs::symlink_dir
2615///
2616/// # Examples
2617///
2618/// ```no_run
2619/// use std::fs;
2620///
2621/// fn main() -> std::io::Result<()> {
2622/// fs::soft_link("a.txt", "b.txt")?;
2623/// Ok(())
2624/// }
2625/// ```
2626#[stable(feature = "rust1", since = "1.0.0")]
2627#[deprecated(
2628 since = "1.1.0",
2629 note = "replaced with std::os::unix::fs::symlink and \
2630 std::os::windows::fs::{symlink_file, symlink_dir}"
2631)]
2632pub fn soft_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
2633 fs_imp::symlink(original.as_ref(), link.as_ref())
2634}
2635
2636/// Reads a symbolic link, returning the file that the link points to.
2637///
2638/// # Platform-specific behavior
2639///
2640/// This function currently corresponds to the `readlink` function on Unix
2641/// and the `CreateFile` function with `FILE_FLAG_OPEN_REPARSE_POINT` and
2642/// `FILE_FLAG_BACKUP_SEMANTICS` flags on Windows.
2643/// Note that, this [may change in the future][changes].
2644///
2645/// [changes]: io#platform-specific-behavior
2646///
2647/// # Errors
2648///
2649/// This function will return an error in the following situations, but is not
2650/// limited to just these cases:
2651///
2652/// * `path` is not a symbolic link.
2653/// * `path` does not exist.
2654///
2655/// # Examples
2656///
2657/// ```no_run
2658/// use std::fs;
2659///
2660/// fn main() -> std::io::Result<()> {
2661/// let path = fs::read_link("a.txt")?;
2662/// Ok(())
2663/// }
2664/// ```
2665#[stable(feature = "rust1", since = "1.0.0")]
2666pub fn read_link<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
2667 fs_imp::readlink(path.as_ref())
2668}
2669
2670/// Returns the canonical, absolute form of a path with all intermediate
2671/// components normalized and symbolic links resolved.
2672///
2673/// # Platform-specific behavior
2674///
2675/// This function currently corresponds to the `realpath` function on Unix
2676/// and the `CreateFile` and `GetFinalPathNameByHandle` functions on Windows.
2677/// Note that this [may change in the future][changes].
2678///
2679/// On Windows, this converts the path to use [extended length path][path]
2680/// syntax, which allows your program to use longer path names, but means you
2681/// can only join backslash-delimited paths to it, and it may be incompatible
2682/// with other applications (if passed to the application on the command-line,
2683/// or written to a file another application may read).
2684///
2685/// [changes]: io#platform-specific-behavior
2686/// [path]: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
2687///
2688/// # Errors
2689///
2690/// This function will return an error in the following situations, but is not
2691/// limited to just these cases:
2692///
2693/// * `path` does not exist.
2694/// * A non-final component in path is not a directory.
2695///
2696/// # Examples
2697///
2698/// ```no_run
2699/// use std::fs;
2700///
2701/// fn main() -> std::io::Result<()> {
2702/// let path = fs::canonicalize("../a/../foo.txt")?;
2703/// Ok(())
2704/// }
2705/// ```
2706#[doc(alias = "realpath")]
2707#[doc(alias = "GetFinalPathNameByHandle")]
2708#[stable(feature = "fs_canonicalize", since = "1.5.0")]
2709pub fn canonicalize<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
2710 fs_imp::canonicalize(path.as_ref())
2711}
2712
2713/// Creates a new, empty directory at the provided path
2714///
2715/// # Platform-specific behavior
2716///
2717/// This function currently corresponds to the `mkdir` function on Unix
2718/// and the `CreateDirectoryW` function on Windows.
2719/// Note that, this [may change in the future][changes].
2720///
2721/// [changes]: io#platform-specific-behavior
2722///
2723/// **NOTE**: If a parent of the given path doesn't exist, this function will
2724/// return an error. To create a directory and all its missing parents at the
2725/// same time, use the [`create_dir_all`] function.
2726///
2727/// # Errors
2728///
2729/// This function will return an error in the following situations, but is not
2730/// limited to just these cases:
2731///
2732/// * User lacks permissions to create directory at `path`.
2733/// * A parent of the given path doesn't exist. (To create a directory and all
2734/// its missing parents at the same time, use the [`create_dir_all`]
2735/// function.)
2736/// * `path` already exists.
2737///
2738/// # Examples
2739///
2740/// ```no_run
2741/// use std::fs;
2742///
2743/// fn main() -> std::io::Result<()> {
2744/// fs::create_dir("/some/dir")?;
2745/// Ok(())
2746/// }
2747/// ```
2748#[doc(alias = "mkdir", alias = "CreateDirectory")]
2749#[stable(feature = "rust1", since = "1.0.0")]
2750#[cfg_attr(not(test), rustc_diagnostic_item = "fs_create_dir")]
2751pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
2752 DirBuilder::new().create(path.as_ref())
2753}
2754
2755/// Recursively create a directory and all of its parent components if they
2756/// are missing.
2757///
2758/// If this function returns an error, some of the parent components might have
2759/// been created already.
2760///
2761/// If the empty path is passed to this function, it always succeeds without
2762/// creating any directories.
2763///
2764/// # Platform-specific behavior
2765///
2766/// This function currently corresponds to multiple calls to the `mkdir`
2767/// function on Unix and the `CreateDirectoryW` function on Windows.
2768///
2769/// Note that, this [may change in the future][changes].
2770///
2771/// [changes]: io#platform-specific-behavior
2772///
2773/// # Errors
2774///
2775/// The function will return an error if any directory specified in path does not exist and
2776/// could not be created. There may be other error conditions; see [`fs::create_dir`] for specifics.
2777///
2778/// Notable exception is made for situations where any of the directories
2779/// specified in the `path` could not be created as it was being created concurrently.
2780/// Such cases are considered to be successful. That is, calling `create_dir_all`
2781/// concurrently from multiple threads or processes is guaranteed not to fail
2782/// due to a race condition with itself.
2783///
2784/// [`fs::create_dir`]: create_dir
2785///
2786/// # Examples
2787///
2788/// ```no_run
2789/// use std::fs;
2790///
2791/// fn main() -> std::io::Result<()> {
2792/// fs::create_dir_all("/some/dir")?;
2793/// Ok(())
2794/// }
2795/// ```
2796#[stable(feature = "rust1", since = "1.0.0")]
2797pub fn create_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
2798 DirBuilder::new().recursive(true).create(path.as_ref())
2799}
2800
2801/// Removes an empty directory.
2802///
2803/// If you want to remove a directory that is not empty, as well as all
2804/// of its contents recursively, consider using [`remove_dir_all`]
2805/// instead.
2806///
2807/// # Platform-specific behavior
2808///
2809/// This function currently corresponds to the `rmdir` function on Unix
2810/// and the `RemoveDirectory` function on Windows.
2811/// Note that, this [may change in the future][changes].
2812///
2813/// [changes]: io#platform-specific-behavior
2814///
2815/// # Errors
2816///
2817/// This function will return an error in the following situations, but is not
2818/// limited to just these cases:
2819///
2820/// * `path` doesn't exist.
2821/// * `path` isn't a directory.
2822/// * The user lacks permissions to remove the directory at the provided `path`.
2823/// * The directory isn't empty.
2824///
2825/// This function will only ever return an error of kind `NotFound` if the given
2826/// path does not exist. Note that the inverse is not true,
2827/// ie. if a path does not exist, its removal may fail for a number of reasons,
2828/// such as insufficient permissions.
2829///
2830/// # Examples
2831///
2832/// ```no_run
2833/// use std::fs;
2834///
2835/// fn main() -> std::io::Result<()> {
2836/// fs::remove_dir("/some/dir")?;
2837/// Ok(())
2838/// }
2839/// ```
2840#[doc(alias = "rmdir", alias = "RemoveDirectory")]
2841#[stable(feature = "rust1", since = "1.0.0")]
2842pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
2843 fs_imp::rmdir(path.as_ref())
2844}
2845
2846/// Removes a directory at this path, after removing all its contents. Use
2847/// carefully!
2848///
2849/// This function does **not** follow symbolic links and it will simply remove the
2850/// symbolic link itself.
2851///
2852/// # Platform-specific behavior
2853///
2854/// This function currently corresponds to `openat`, `fdopendir`, `unlinkat` and `lstat` functions
2855/// on Unix (except for REDOX) and the `CreateFileW`, `GetFileInformationByHandleEx`,
2856/// `SetFileInformationByHandle`, and `NtCreateFile` functions on Windows. Note that, this
2857/// [may change in the future][changes].
2858///
2859/// [changes]: io#platform-specific-behavior
2860///
2861/// On REDOX, as well as when running in Miri for any target, this function is not protected against
2862/// time-of-check to time-of-use (TOCTOU) race conditions, and should not be used in
2863/// security-sensitive code on those platforms. All other platforms are protected.
2864///
2865/// # Errors
2866///
2867/// See [`fs::remove_file`] and [`fs::remove_dir`].
2868///
2869/// [`remove_dir_all`] will fail if [`remove_dir`] or [`remove_file`] fail on *any* constituent
2870/// paths, *including* the root `path`. Consequently,
2871///
2872/// - The directory you are deleting *must* exist, meaning that this function is *not idempotent*.
2873/// - [`remove_dir_all`] will fail if the `path` is *not* a directory.
2874///
2875/// Consider ignoring the error if validating the removal is not required for your use case.
2876///
2877/// [`io::ErrorKind::NotFound`] is only returned if no removal occurs.
2878///
2879/// [`fs::remove_file`]: remove_file
2880/// [`fs::remove_dir`]: remove_dir
2881///
2882/// # Examples
2883///
2884/// ```no_run
2885/// use std::fs;
2886///
2887/// fn main() -> std::io::Result<()> {
2888/// fs::remove_dir_all("/some/dir")?;
2889/// Ok(())
2890/// }
2891/// ```
2892#[stable(feature = "rust1", since = "1.0.0")]
2893pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
2894 fs_imp::remove_dir_all(path.as_ref())
2895}
2896
2897/// Returns an iterator over the entries within a directory.
2898///
2899/// The iterator will yield instances of <code>[io::Result]<[DirEntry]></code>.
2900/// New errors may be encountered after an iterator is initially constructed.
2901/// Entries for the current and parent directories (typically `.` and `..`) are
2902/// skipped.
2903///
2904/// # Platform-specific behavior
2905///
2906/// This function currently corresponds to the `opendir` function on Unix
2907/// and the `FindFirstFileEx` function on Windows. Advancing the iterator
2908/// currently corresponds to `readdir` on Unix and `FindNextFile` on Windows.
2909/// Note that, this [may change in the future][changes].
2910///
2911/// [changes]: io#platform-specific-behavior
2912///
2913/// The order in which this iterator returns entries is platform and filesystem
2914/// dependent.
2915///
2916/// # Errors
2917///
2918/// This function will return an error in the following situations, but is not
2919/// limited to just these cases:
2920///
2921/// * The provided `path` doesn't exist.
2922/// * The process lacks permissions to view the contents.
2923/// * The `path` points at a non-directory file.
2924///
2925/// # Examples
2926///
2927/// ```
2928/// use std::io;
2929/// use std::fs::{self, DirEntry};
2930/// use std::path::Path;
2931///
2932/// // one possible implementation of walking a directory only visiting files
2933/// fn visit_dirs(dir: &Path, cb: &dyn Fn(&DirEntry)) -> io::Result<()> {
2934/// if dir.is_dir() {
2935/// for entry in fs::read_dir(dir)? {
2936/// let entry = entry?;
2937/// let path = entry.path();
2938/// if path.is_dir() {
2939/// visit_dirs(&path, cb)?;
2940/// } else {
2941/// cb(&entry);
2942/// }
2943/// }
2944/// }
2945/// Ok(())
2946/// }
2947/// ```
2948///
2949/// ```rust,no_run
2950/// use std::{fs, io};
2951///
2952/// fn main() -> io::Result<()> {
2953/// let mut entries = fs::read_dir(".")?
2954/// .map(|res| res.map(|e| e.path()))
2955/// .collect::<Result<Vec<_>, io::Error>>()?;
2956///
2957/// // The order in which `read_dir` returns entries is not guaranteed. If reproducible
2958/// // ordering is required the entries should be explicitly sorted.
2959///
2960/// entries.sort();
2961///
2962/// // The entries have now been sorted by their path.
2963///
2964/// Ok(())
2965/// }
2966/// ```
2967#[doc(alias = "ls", alias = "opendir", alias = "FindFirstFile", alias = "FindNextFile")]
2968#[stable(feature = "rust1", since = "1.0.0")]
2969pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
2970 fs_imp::readdir(path.as_ref()).map(op:ReadDir)
2971}
2972
2973/// Changes the permissions found on a file or a directory.
2974///
2975/// # Platform-specific behavior
2976///
2977/// This function currently corresponds to the `chmod` function on Unix
2978/// and the `SetFileAttributes` function on Windows.
2979/// Note that, this [may change in the future][changes].
2980///
2981/// [changes]: io#platform-specific-behavior
2982///
2983/// # Errors
2984///
2985/// This function will return an error in the following situations, but is not
2986/// limited to just these cases:
2987///
2988/// * `path` does not exist.
2989/// * The user lacks the permission to change attributes of the file.
2990///
2991/// # Examples
2992///
2993/// ```no_run
2994/// use std::fs;
2995///
2996/// fn main() -> std::io::Result<()> {
2997/// let mut perms = fs::metadata("foo.txt")?.permissions();
2998/// perms.set_readonly(true);
2999/// fs::set_permissions("foo.txt", perms)?;
3000/// Ok(())
3001/// }
3002/// ```
3003#[doc(alias = "chmod", alias = "SetFileAttributes")]
3004#[stable(feature = "set_permissions", since = "1.1.0")]
3005pub fn set_permissions<P: AsRef<Path>>(path: P, perm: Permissions) -> io::Result<()> {
3006 fs_imp::set_perm(p:path.as_ref(), perm.0)
3007}
3008
3009impl DirBuilder {
3010 /// Creates a new set of options with default mode/security settings for all
3011 /// platforms and also non-recursive.
3012 ///
3013 /// # Examples
3014 ///
3015 /// ```
3016 /// use std::fs::DirBuilder;
3017 ///
3018 /// let builder = DirBuilder::new();
3019 /// ```
3020 #[stable(feature = "dir_builder", since = "1.6.0")]
3021 #[must_use]
3022 pub fn new() -> DirBuilder {
3023 DirBuilder { inner: fs_imp::DirBuilder::new(), recursive: false }
3024 }
3025
3026 /// Indicates that directories should be created recursively, creating all
3027 /// parent directories. Parents that do not exist are created with the same
3028 /// security and permissions settings.
3029 ///
3030 /// This option defaults to `false`.
3031 ///
3032 /// # Examples
3033 ///
3034 /// ```
3035 /// use std::fs::DirBuilder;
3036 ///
3037 /// let mut builder = DirBuilder::new();
3038 /// builder.recursive(true);
3039 /// ```
3040 #[stable(feature = "dir_builder", since = "1.6.0")]
3041 pub fn recursive(&mut self, recursive: bool) -> &mut Self {
3042 self.recursive = recursive;
3043 self
3044 }
3045
3046 /// Creates the specified directory with the options configured in this
3047 /// builder.
3048 ///
3049 /// It is considered an error if the directory already exists unless
3050 /// recursive mode is enabled.
3051 ///
3052 /// # Examples
3053 ///
3054 /// ```no_run
3055 /// use std::fs::{self, DirBuilder};
3056 ///
3057 /// let path = "/tmp/foo/bar/baz";
3058 /// DirBuilder::new()
3059 /// .recursive(true)
3060 /// .create(path).unwrap();
3061 ///
3062 /// assert!(fs::metadata(path).unwrap().is_dir());
3063 /// ```
3064 #[stable(feature = "dir_builder", since = "1.6.0")]
3065 pub fn create<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
3066 self._create(path.as_ref())
3067 }
3068
3069 fn _create(&self, path: &Path) -> io::Result<()> {
3070 if self.recursive { self.create_dir_all(path) } else { self.inner.mkdir(path) }
3071 }
3072
3073 fn create_dir_all(&self, path: &Path) -> io::Result<()> {
3074 if path == Path::new("") {
3075 return Ok(());
3076 }
3077
3078 match self.inner.mkdir(path) {
3079 Ok(()) => return Ok(()),
3080 Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
3081 Err(_) if path.is_dir() => return Ok(()),
3082 Err(e) => return Err(e),
3083 }
3084 match path.parent() {
3085 Some(p) => self.create_dir_all(p)?,
3086 None => {
3087 return Err(io::const_error!(
3088 io::ErrorKind::Uncategorized,
3089 "failed to create whole tree",
3090 ));
3091 }
3092 }
3093 match self.inner.mkdir(path) {
3094 Ok(()) => Ok(()),
3095 Err(_) if path.is_dir() => Ok(()),
3096 Err(e) => Err(e),
3097 }
3098 }
3099}
3100
3101impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
3102 #[inline]
3103 fn as_inner_mut(&mut self) -> &mut fs_imp::DirBuilder {
3104 &mut self.inner
3105 }
3106}
3107
3108/// Returns `Ok(true)` if the path points at an existing entity.
3109///
3110/// This function will traverse symbolic links to query information about the
3111/// destination file. In case of broken symbolic links this will return `Ok(false)`.
3112///
3113/// As opposed to the [`Path::exists`] method, this will only return `Ok(true)` or `Ok(false)`
3114/// if the path was _verified_ to exist or not exist. If its existence can neither be confirmed
3115/// nor denied, an `Err(_)` will be propagated instead. This can be the case if e.g. listing
3116/// permission is denied on one of the parent directories.
3117///
3118/// Note that while this avoids some pitfalls of the `exists()` method, it still can not
3119/// prevent time-of-check to time-of-use (TOCTOU) bugs. You should only use it in scenarios
3120/// where those bugs are not an issue.
3121///
3122/// # Examples
3123///
3124/// ```no_run
3125/// use std::fs;
3126///
3127/// assert!(!fs::exists("does_not_exist.txt").expect("Can't check existence of file does_not_exist.txt"));
3128/// assert!(fs::exists("/root/secret_file.txt").is_err());
3129/// ```
3130///
3131/// [`Path::exists`]: crate::path::Path::exists
3132#[stable(feature = "fs_try_exists", since = "1.81.0")]
3133#[inline]
3134pub fn exists<P: AsRef<Path>>(path: P) -> io::Result<bool> {
3135 fs_imp::exists(path.as_ref())
3136}
3137

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