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fuchsia / third_party / rust / e3029abfaec4252ab0ae7010780be0094d8870e0 / . / library / std / src / fs.rs
blob: 675140ff18f5f984e49ff38fd38303cd338c6127 [file] [log] [blame]
//! Filesystem manipulation operations.
//!
//! This module contains basic methods to manipulate the contents of the local
//! filesystem. All methods in this module represent cross-platform filesystem
//! operations. Extra platform-specific functionality can be found in the
//! extension traits of `std::os::$platform`.
#![stable(feature = "rust1", since = "1.0.0")]
#![deny(unsafe_op_in_unsafe_fn)]
#[cfg(all(
test,
not(any(
target_os = "emscripten",
target_os = "wasi",
target_env = "sgx",
target_os = "xous"
))
))]
mod tests;
use crate::ffi::OsString;
use crate::fmt;
use crate::io::{self, BorrowedCursor, IoSlice, IoSliceMut, Read, Seek, SeekFrom, Write};
use crate::path::{Path, PathBuf};
use crate::sealed::Sealed;
use crate::sync::Arc;
use crate::sys::fs as fs_imp;
use crate::sys_common::{AsInner, AsInnerMut, FromInner, IntoInner};
use crate::time::SystemTime;
/// An object providing access to an open file on the filesystem.
///
/// An instance of a `File` can be read and/or written depending on what options
/// it was opened with. Files also implement [`Seek`] to alter the logical cursor
/// that the file contains internally.
///
/// Files are automatically closed when they go out of scope. Errors detected
/// on closing are ignored by the implementation of `Drop`. Use the method
/// [`sync_all`] if these errors must be manually handled.
///
/// `File` does not buffer reads and writes. For efficiency, consider wrapping the
/// file in a [`BufReader`] or [`BufWriter`] when performing many small [`read`]
/// or [`write`] calls, unless unbuffered reads and writes are required.
///
/// # Examples
///
/// Creates a new file and write bytes to it (you can also use [`write`]):
///
/// ```no_run
/// use std::fs::File;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut file = File::create("foo.txt")?;
/// file.write_all(b"Hello, world!")?;
/// Ok(())
/// }
/// ```
///
/// Reads the contents of a file into a [`String`] (you can also use [`read`]):
///
/// ```no_run
/// use std::fs::File;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut file = File::open("foo.txt")?;
/// let mut contents = String::new();
/// file.read_to_string(&mut contents)?;
/// assert_eq!(contents, "Hello, world!");
/// Ok(())
/// }
/// ```
///
/// Using a buffered [`Read`]er:
///
/// ```no_run
/// use std::fs::File;
/// use std::io::BufReader;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let file = File::open("foo.txt")?;
/// let mut buf_reader = BufReader::new(file);
/// let mut contents = String::new();
/// buf_reader.read_to_string(&mut contents)?;
/// assert_eq!(contents, "Hello, world!");
/// Ok(())
/// }
/// ```
///
/// Note that, although read and write methods require a `&mut File`, because
/// of the interfaces for [`Read`] and [`Write`], the holder of a `&File` can
/// still modify the file, either through methods that take `&File` or by
/// retrieving the underlying OS object and modifying the file that way.
/// Additionally, many operating systems allow concurrent modification of files
/// by different processes. Avoid assuming that holding a `&File` means that the
/// file will not change.
///
/// # Platform-specific behavior
///
/// On Windows, the implementation of [`Read`] and [`Write`] traits for `File`
/// perform synchronous I/O operations. Therefore the underlying file must not
/// have been opened for asynchronous I/O (e.g. by using `FILE_FLAG_OVERLAPPED`).
///
/// [`BufReader`]: io::BufReader
/// [`BufWriter`]: io::BufWriter
/// [`sync_all`]: File::sync_all
/// [`write`]: File::write
/// [`read`]: File::read
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "File")]
pub struct File {
inner: fs_imp::File,
}
/// Metadata information about a file.
///
/// This structure is returned from the [`metadata`] or
/// [`symlink_metadata`] function or method and represents known
/// metadata about a file such as its permissions, size, modification
/// times, etc.
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(Clone)]
pub struct Metadata(fs_imp::FileAttr);
/// Iterator over the entries in a directory.
///
/// This iterator is returned from the [`read_dir`] function of this module and
/// will yield instances of <code>[io::Result]<[DirEntry]></code>. Through a [`DirEntry`]
/// information like the entry's path and possibly other metadata can be
/// learned.
///
/// The order in which this iterator returns entries is platform and filesystem
/// dependent.
///
/// # Errors
///
/// This [`io::Result`] will be an [`Err`] if there's some sort of intermittent
/// IO error during iteration.
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(Debug)]
pub struct ReadDir(fs_imp::ReadDir);
/// Entries returned by the [`ReadDir`] iterator.
///
/// An instance of `DirEntry` represents an entry inside of a directory on the
/// filesystem. Each entry can be inspected via methods to learn about the full
/// path or possibly other metadata through per-platform extension traits.
///
/// # Platform-specific behavior
///
/// On Unix, the `DirEntry` struct contains an internal reference to the open
/// directory. Holding `DirEntry` objects will consume a file handle even
/// after the `ReadDir` iterator is dropped.
///
/// Note that this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[stable(feature = "rust1", since = "1.0.0")]
pub struct DirEntry(fs_imp::DirEntry);
/// Options and flags which can be used to configure how a file is opened.
///
/// This builder exposes the ability to configure how a [`File`] is opened and
/// what operations are permitted on the open file. The [`File::open`] and
/// [`File::create`] methods are aliases for commonly used options using this
/// builder.
///
/// Generally speaking, when using `OpenOptions`, you'll first call
/// [`OpenOptions::new`], then chain calls to methods to set each option, then
/// call [`OpenOptions::open`], passing the path of the file you're trying to
/// open. This will give you a [`io::Result`] with a [`File`] inside that you
/// can further operate on.
///
/// # Examples
///
/// Opening a file to read:
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().read(true).open("foo.txt");
/// ```
///
/// Opening a file for both reading and writing, as well as creating it if it
/// doesn't exist:
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new()
/// .read(true)
/// .write(true)
/// .create(true)
/// .open("foo.txt");
/// ```
#[derive(Clone, Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "FsOpenOptions")]
pub struct OpenOptions(fs_imp::OpenOptions);
/// Representation of the various timestamps on a file.
#[derive(Copy, Clone, Debug, Default)]
#[stable(feature = "file_set_times", since = "1.75.0")]
pub struct FileTimes(fs_imp::FileTimes);
/// Representation of the various permissions on a file.
///
/// This module only currently provides one bit of information,
/// [`Permissions::readonly`], which is exposed on all currently supported
/// platforms. Unix-specific functionality, such as mode bits, is available
/// through the [`PermissionsExt`] trait.
///
/// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
#[derive(Clone, PartialEq, Eq, Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "FsPermissions")]
pub struct Permissions(fs_imp::FilePermissions);
/// A structure representing a type of file with accessors for each file type.
/// It is returned by [`Metadata::file_type`] method.
#[stable(feature = "file_type", since = "1.1.0")]
#[derive(Copy, Clone, PartialEq, Eq, Hash)]
#[cfg_attr(not(test), rustc_diagnostic_item = "FileType")]
pub struct FileType(fs_imp::FileType);
/// A builder used to create directories in various manners.
///
/// This builder also supports platform-specific options.
#[stable(feature = "dir_builder", since = "1.6.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "DirBuilder")]
#[derive(Debug)]
pub struct DirBuilder {
inner: fs_imp::DirBuilder,
recursive: bool,
}
/// Reads the entire contents of a file into a bytes vector.
///
/// This is a convenience function for using [`File::open`] and [`read_to_end`]
/// with fewer imports and without an intermediate variable.
///
/// [`read_to_end`]: Read::read_to_end
///
/// # Errors
///
/// This function will return an error if `path` does not already exist.
/// Other errors may also be returned according to [`OpenOptions::open`].
///
/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
/// with automatic retries. See [io::Read] documentation for details.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> Result<(), Box<dyn std::error::Error + 'static>> {
/// let data: Vec<u8> = fs::read("image.jpg")?;
/// assert_eq!(data[0..3], [0xFF, 0xD8, 0xFF]);
/// Ok(())
/// }
/// ```
#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
pub fn read<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
fn inner(path: &Path) -> io::Result<Vec<u8>> {
let mut file = File::open(path)?;
let size = file.metadata().map(|m| m.len() as usize).ok();
let mut bytes = Vec::new();
bytes.try_reserve_exact(size.unwrap_or(0))?;
io::default_read_to_end(&mut file, &mut bytes, size)?;
Ok(bytes)
}
inner(path.as_ref())
}
/// Reads the entire contents of a file into a string.
///
/// This is a convenience function for using [`File::open`] and [`read_to_string`]
/// with fewer imports and without an intermediate variable.
///
/// [`read_to_string`]: Read::read_to_string
///
/// # Errors
///
/// This function will return an error if `path` does not already exist.
/// Other errors may also be returned according to [`OpenOptions::open`].
///
/// If the contents of the file are not valid UTF-8, then an error will also be
/// returned.
///
/// While reading from the file, this function handles [`io::ErrorKind::Interrupted`]
/// with automatic retries. See [io::Read] documentation for details.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
/// use std::error::Error;
///
/// fn main() -> Result<(), Box<dyn Error>> {
/// let message: String = fs::read_to_string("message.txt")?;
/// println!("{}", message);
/// Ok(())
/// }
/// ```
#[stable(feature = "fs_read_write", since = "1.26.0")]
pub fn read_to_string<P: AsRef<Path>>(path: P) -> io::Result<String> {
fn inner(path: &Path) -> io::Result<String> {
let mut file = File::open(path)?;
let size = file.metadata().map(|m| m.len() as usize).ok();
let mut string = String::new();
string.try_reserve_exact(size.unwrap_or(0))?;
io::default_read_to_string(&mut file, &mut string, size)?;
Ok(string)
}
inner(path.as_ref())
}
/// Writes a slice as the entire contents of a file.
///
/// This function will create a file if it does not exist,
/// and will entirely replace its contents if it does.
///
/// Depending on the platform, this function may fail if the
/// full directory path does not exist.
///
/// This is a convenience function for using [`File::create`] and [`write_all`]
/// with fewer imports.
///
/// [`write_all`]: Write::write_all
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::write("foo.txt", b"Lorem ipsum")?;
/// fs::write("bar.txt", "dolor sit")?;
/// Ok(())
/// }
/// ```
#[stable(feature = "fs_read_write_bytes", since = "1.26.0")]
pub fn write<P: AsRef<Path>, C: AsRef<[u8]>>(path: P, contents: C) -> io::Result<()> {
fn inner(path: &Path, contents: &[u8]) -> io::Result<()> {
File::create(path)?.write_all(contents)
}
inner(path.as_ref(), contents.as_ref())
}
impl File {
/// Attempts to open a file in read-only mode.
///
/// See the [`OpenOptions::open`] method for more details.
///
/// If you only need to read the entire file contents,
/// consider [`std::fs::read()`][self::read] or
/// [`std::fs::read_to_string()`][self::read_to_string] instead.
///
/// # Errors
///
/// This function will return an error if `path` does not already exist.
/// Other errors may also be returned according to [`OpenOptions::open`].
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::Read;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::open("foo.txt")?;
/// let mut data = vec![];
/// f.read_to_end(&mut data)?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn open<P: AsRef<Path>>(path: P) -> io::Result<File> {
OpenOptions::new().read(true).open(path.as_ref())
}
/// Attempts to open a file in read-only mode with buffering.
///
/// See the [`OpenOptions::open`] method, the [`BufReader`][io::BufReader] type,
/// and the [`BufRead`][io::BufRead] trait for more details.
///
/// If you only need to read the entire file contents,
/// consider [`std::fs::read()`][self::read] or
/// [`std::fs::read_to_string()`][self::read_to_string] instead.
///
/// # Errors
///
/// This function will return an error if `path` does not already exist,
/// or if memory allocation fails for the new buffer.
/// Other errors may also be returned according to [`OpenOptions::open`].
///
/// # Examples
///
/// ```no_run
/// #![feature(file_buffered)]
/// use std::fs::File;
/// use std::io::BufRead;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::open_buffered("foo.txt")?;
/// assert!(f.capacity() > 0);
/// for (line, i) in f.lines().zip(1..) {
/// println!("{i:6}: {}", line?);
/// }
/// Ok(())
/// }
/// ```
#[unstable(feature = "file_buffered", issue = "130804")]
pub fn open_buffered<P: AsRef<Path>>(path: P) -> io::Result<io::BufReader<File>> {
// Allocate the buffer *first* so we don't affect the filesystem otherwise.
let buffer = io::BufReader::<Self>::try_new_buffer()?;
let file = File::open(path)?;
Ok(io::BufReader::with_buffer(file, buffer))
}
/// Opens a file in write-only mode.
///
/// This function will create a file if it does not exist,
/// and will truncate it if it does.
///
/// Depending on the platform, this function may fail if the
/// full directory path does not exist.
/// See the [`OpenOptions::open`] function for more details.
///
/// See also [`std::fs::write()`][self::write] for a simple function to
/// create a file with some given data.
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::Write;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create("foo.txt")?;
/// f.write_all(&1234_u32.to_be_bytes())?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn create<P: AsRef<Path>>(path: P) -> io::Result<File> {
OpenOptions::new().write(true).create(true).truncate(true).open(path.as_ref())
}
/// Opens a file in write-only mode with buffering.
///
/// This function will create a file if it does not exist,
/// and will truncate it if it does.
///
/// Depending on the platform, this function may fail if the
/// full directory path does not exist.
///
/// See the [`OpenOptions::open`] method and the
/// [`BufWriter`][io::BufWriter] type for more details.
///
/// See also [`std::fs::write()`][self::write] for a simple function to
/// create a file with some given data.
///
/// # Examples
///
/// ```no_run
/// #![feature(file_buffered)]
/// use std::fs::File;
/// use std::io::Write;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create_buffered("foo.txt")?;
/// assert!(f.capacity() > 0);
/// for i in 0..100 {
/// writeln!(&mut f, "{i}")?;
/// }
/// f.flush()?;
/// Ok(())
/// }
/// ```
#[unstable(feature = "file_buffered", issue = "130804")]
pub fn create_buffered<P: AsRef<Path>>(path: P) -> io::Result<io::BufWriter<File>> {
// Allocate the buffer *first* so we don't affect the filesystem otherwise.
let buffer = io::BufWriter::<Self>::try_new_buffer()?;
let file = File::create(path)?;
Ok(io::BufWriter::with_buffer(file, buffer))
}
/// Creates a new file in read-write mode; error if the file exists.
///
/// This function will create a file if it does not exist, or return an error if it does. This
/// way, if the call succeeds, the file returned is guaranteed to be new.
/// If a file exists at the target location, creating a new file will fail with [`AlreadyExists`]
/// or another error based on the situation. See [`OpenOptions::open`] for a
/// non-exhaustive list of likely errors.
///
/// This option is useful because it is atomic. Otherwise between checking whether a file
/// exists and creating a new one, the file may have been created by another process (a TOCTOU
/// race condition / attack).
///
/// This can also be written using
/// `File::options().read(true).write(true).create_new(true).open(...)`.
///
/// [`AlreadyExists`]: crate::io::ErrorKind::AlreadyExists
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::Write;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create_new("foo.txt")?;
/// f.write_all("Hello, world!".as_bytes())?;
/// Ok(())
/// }
/// ```
#[stable(feature = "file_create_new", since = "1.77.0")]
pub fn create_new<P: AsRef<Path>>(path: P) -> io::Result<File> {
OpenOptions::new().read(true).write(true).create_new(true).open(path.as_ref())
}
/// Returns a new OpenOptions object.
///
/// This function returns a new OpenOptions object that you can use to
/// open or create a file with specific options if `open()` or `create()`
/// are not appropriate.
///
/// It is equivalent to `OpenOptions::new()`, but allows you to write more
/// readable code. Instead of
/// `OpenOptions::new().append(true).open("example.log")`,
/// you can write `File::options().append(true).open("example.log")`. This
/// also avoids the need to import `OpenOptions`.
///
/// See the [`OpenOptions::new`] function for more details.
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::Write;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::options().append(true).open("example.log")?;
/// writeln!(&mut f, "new line")?;
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "with_options", since = "1.58.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "file_options")]
pub fn options() -> OpenOptions {
OpenOptions::new()
}
/// Attempts to sync all OS-internal file content and metadata to disk.
///
/// This function will attempt to ensure that all in-memory data reaches the
/// filesystem before returning.
///
/// This can be used to handle errors that would otherwise only be caught
/// when the `File` is closed, as dropping a `File` will ignore all errors.
/// Note, however, that `sync_all` is generally more expensive than closing
/// a file by dropping it, because the latter is not required to block until
/// the data has been written to the filesystem.
///
/// If synchronizing the metadata is not required, use [`sync_data`] instead.
///
/// [`sync_data`]: File::sync_data
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create("foo.txt")?;
/// f.write_all(b"Hello, world!")?;
///
/// f.sync_all()?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(alias = "fsync")]
pub fn sync_all(&self) -> io::Result<()> {
self.inner.fsync()
}
/// This function is similar to [`sync_all`], except that it might not
/// synchronize file metadata to the filesystem.
///
/// This is intended for use cases that must synchronize content, but don't
/// need the metadata on disk. The goal of this method is to reduce disk
/// operations.
///
/// Note that some platforms may simply implement this in terms of
/// [`sync_all`].
///
/// [`sync_all`]: File::sync_all
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create("foo.txt")?;
/// f.write_all(b"Hello, world!")?;
///
/// f.sync_data()?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[doc(alias = "fdatasync")]
pub fn sync_data(&self) -> io::Result<()> {
self.inner.datasync()
}
/// Truncates or extends the underlying file, updating the size of
/// this file to become `size`.
///
/// If the `size` is less than the current file's size, then the file will
/// be shrunk. If it is greater than the current file's size, then the file
/// will be extended to `size` and have all of the intermediate data filled
/// in with 0s.
///
/// The file's cursor isn't changed. In particular, if the cursor was at the
/// end and the file is shrunk using this operation, the cursor will now be
/// past the end.
///
/// # Errors
///
/// This function will return an error if the file is not opened for writing.
/// Also, [`std::io::ErrorKind::InvalidInput`](crate::io::ErrorKind::InvalidInput)
/// will be returned if the desired length would cause an overflow due to
/// the implementation specifics.
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create("foo.txt")?;
/// f.set_len(10)?;
/// Ok(())
/// }
/// ```
///
/// Note that this method alters the content of the underlying file, even
/// though it takes `&self` rather than `&mut self`.
#[stable(feature = "rust1", since = "1.0.0")]
pub fn set_len(&self, size: u64) -> io::Result<()> {
self.inner.truncate(size)
}
/// Queries metadata about the underlying file.
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::open("foo.txt")?;
/// let metadata = f.metadata()?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn metadata(&self) -> io::Result<Metadata> {
self.inner.file_attr().map(Metadata)
}
/// Creates a new `File` instance that shares the same underlying file handle
/// as the existing `File` instance. Reads, writes, and seeks will affect
/// both `File` instances simultaneously.
///
/// # Examples
///
/// Creates two handles for a file named `foo.txt`:
///
/// ```no_run
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let mut file = File::open("foo.txt")?;
/// let file_copy = file.try_clone()?;
/// Ok(())
/// }
/// ```
///
/// Assuming there’s a file named `foo.txt` with contents `abcdef\n`, create
/// two handles, seek one of them, and read the remaining bytes from the
/// other handle:
///
/// ```no_run
/// use std::fs::File;
/// use std::io::SeekFrom;
/// use std::io::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut file = File::open("foo.txt")?;
/// let mut file_copy = file.try_clone()?;
///
/// file.seek(SeekFrom::Start(3))?;
///
/// let mut contents = vec![];
/// file_copy.read_to_end(&mut contents)?;
/// assert_eq!(contents, b"def\n");
/// Ok(())
/// }
/// ```
#[stable(feature = "file_try_clone", since = "1.9.0")]
pub fn try_clone(&self) -> io::Result<File> {
Ok(File { inner: self.inner.duplicate()? })
}
/// Changes the permissions on the underlying file.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `fchmod` function on Unix and
/// the `SetFileInformationByHandle` function on Windows. Note that, this
/// [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error if the user lacks permission change
/// attributes on the underlying file. It may also return an error in other
/// os-specific unspecified cases.
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs::File;
///
/// let file = File::open("foo.txt")?;
/// let mut perms = file.metadata()?.permissions();
/// perms.set_readonly(true);
/// file.set_permissions(perms)?;
/// Ok(())
/// }
/// ```
///
/// Note that this method alters the permissions of the underlying file,
/// even though it takes `&self` rather than `&mut self`.
#[doc(alias = "fchmod", alias = "SetFileInformationByHandle")]
#[stable(feature = "set_permissions_atomic", since = "1.16.0")]
pub fn set_permissions(&self, perm: Permissions) -> io::Result<()> {
self.inner.set_permissions(perm.0)
}
/// Changes the timestamps of the underlying file.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `futimens` function on Unix (falling back to
/// `futimes` on macOS before 10.13) and the `SetFileTime` function on Windows. Note that this
/// [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error if the user lacks permission to change timestamps on the
/// underlying file. It may also return an error in other os-specific unspecified cases.
///
/// This function may return an error if the operating system lacks support to change one or
/// more of the timestamps set in the `FileTimes` structure.
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs::{self, File, FileTimes};
///
/// let src = fs::metadata("src")?;
/// let dest = File::options().write(true).open("dest")?;
/// let times = FileTimes::new()
/// .set_accessed(src.accessed()?)
/// .set_modified(src.modified()?);
/// dest.set_times(times)?;
/// Ok(())
/// }
/// ```
#[stable(feature = "file_set_times", since = "1.75.0")]
#[doc(alias = "futimens")]
#[doc(alias = "futimes")]
#[doc(alias = "SetFileTime")]
pub fn set_times(&self, times: FileTimes) -> io::Result<()> {
self.inner.set_times(times.0)
}
/// Changes the modification time of the underlying file.
///
/// This is an alias for `set_times(FileTimes::new().set_modified(time))`.
#[stable(feature = "file_set_times", since = "1.75.0")]
#[inline]
pub fn set_modified(&self, time: SystemTime) -> io::Result<()> {
self.set_times(FileTimes::new().set_modified(time))
}
}
// In addition to the `impl`s here, `File` also has `impl`s for
// `AsFd`/`From<OwnedFd>`/`Into<OwnedFd>` and
// `AsRawFd`/`IntoRawFd`/`FromRawFd`, on Unix and WASI, and
// `AsHandle`/`From<OwnedHandle>`/`Into<OwnedHandle>` and
// `AsRawHandle`/`IntoRawHandle`/`FromRawHandle` on Windows.
impl AsInner<fs_imp::File> for File {
#[inline]
fn as_inner(&self) -> &fs_imp::File {
&self.inner
}
}
impl FromInner<fs_imp::File> for File {
fn from_inner(f: fs_imp::File) -> File {
File { inner: f }
}
}
impl IntoInner<fs_imp::File> for File {
fn into_inner(self) -> fs_imp::File {
self.inner
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl fmt::Debug for File {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.inner.fmt(f)
}
}
/// Indicates how much extra capacity is needed to read the rest of the file.
fn buffer_capacity_required(mut file: &File) -> Option<usize> {
let size = file.metadata().map(|m| m.len()).ok()?;
let pos = file.stream_position().ok()?;
// Don't worry about `usize` overflow because reading will fail regardless
// in that case.
Some(size.saturating_sub(pos) as usize)
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Read for &File {
/// Reads some bytes from the file.
///
/// See [`Read::read`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `read` function on Unix and
/// the `NtReadFile` function on Windows. Note that this [may change in
/// the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[inline]
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
self.inner.read(buf)
}
/// Like `read`, except that it reads into a slice of buffers.
///
/// See [`Read::read_vectored`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `readv` function on Unix and
/// falls back to the `read` implementation on Windows. Note that this
/// [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[inline]
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
self.inner.read_vectored(bufs)
}
#[inline]
fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
self.inner.read_buf(cursor)
}
/// Determines if `File` has an efficient `read_vectored` implementation.
///
/// See [`Read::is_read_vectored`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently returns `true` on Unix an `false` on Windows.
/// Note that this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[inline]
fn is_read_vectored(&self) -> bool {
self.inner.is_read_vectored()
}
// Reserves space in the buffer based on the file size when available.
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
let size = buffer_capacity_required(self);
buf.try_reserve(size.unwrap_or(0))?;
io::default_read_to_end(self, buf, size)
}
// Reserves space in the buffer based on the file size when available.
fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
let size = buffer_capacity_required(self);
buf.try_reserve(size.unwrap_or(0))?;
io::default_read_to_string(self, buf, size)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Write for &File {
/// Writes some bytes to the file.
///
/// See [`Write::write`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `write` function on Unix and
/// the `NtWriteFile` function on Windows. Note that this [may change in
/// the future][changes].
///
/// [changes]: io#platform-specific-behavior
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.inner.write(buf)
}
/// Like `write`, except that it writes into a slice of buffers.
///
/// See [`Write::write_vectored`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `writev` function on Unix
/// and falls back to the `write` implementation on Windows. Note that this
/// [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
self.inner.write_vectored(bufs)
}
/// Determines if `File` has an efficient `write_vectored` implementation.
///
/// See [`Write::is_write_vectored`] docs for more info.
///
/// # Platform-specific behavior
///
/// This function currently returns `true` on Unix an `false` on Windows.
/// Note that this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[inline]
fn is_write_vectored(&self) -> bool {
self.inner.is_write_vectored()
}
/// Flushes the file, ensuring that all intermediately buffered contents
/// reach their destination.
///
/// See [`Write::flush`] docs for more info.
///
/// # Platform-specific behavior
///
/// Since a `File` structure doesn't contain any buffers, this function is
/// currently a no-op on Unix and Windows. Note that this [may change in
/// the future][changes].
///
/// [changes]: io#platform-specific-behavior
#[inline]
fn flush(&mut self) -> io::Result<()> {
self.inner.flush()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Seek for &File {
fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
self.inner.seek(pos)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Read for File {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
(&*self).read(buf)
}
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
(&*self).read_vectored(bufs)
}
fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
(&*self).read_buf(cursor)
}
#[inline]
fn is_read_vectored(&self) -> bool {
(&&*self).is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
(&*self).read_to_end(buf)
}
fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
(&*self).read_to_string(buf)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Write for File {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
(&*self).write(buf)
}
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
(&*self).write_vectored(bufs)
}
#[inline]
fn is_write_vectored(&self) -> bool {
(&&*self).is_write_vectored()
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
(&*self).flush()
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Seek for File {
fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
(&*self).seek(pos)
}
}
#[stable(feature = "io_traits_arc", since = "1.73.0")]
impl Read for Arc<File> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
(&**self).read(buf)
}
fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> io::Result<usize> {
(&**self).read_vectored(bufs)
}
fn read_buf(&mut self, cursor: BorrowedCursor<'_>) -> io::Result<()> {
(&**self).read_buf(cursor)
}
#[inline]
fn is_read_vectored(&self) -> bool {
(&**self).is_read_vectored()
}
fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
(&**self).read_to_end(buf)
}
fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
(&**self).read_to_string(buf)
}
}
#[stable(feature = "io_traits_arc", since = "1.73.0")]
impl Write for Arc<File> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
(&**self).write(buf)
}
fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> io::Result<usize> {
(&**self).write_vectored(bufs)
}
#[inline]
fn is_write_vectored(&self) -> bool {
(&**self).is_write_vectored()
}
#[inline]
fn flush(&mut self) -> io::Result<()> {
(&**self).flush()
}
}
#[stable(feature = "io_traits_arc", since = "1.73.0")]
impl Seek for Arc<File> {
fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
(&**self).seek(pos)
}
}
impl OpenOptions {
/// Creates a blank new set of options ready for configuration.
///
/// All options are initially set to `false`.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let mut options = OpenOptions::new();
/// let file = options.read(true).open("foo.txt");
/// ```
#[cfg_attr(not(test), rustc_diagnostic_item = "open_options_new")]
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use]
pub fn new() -> Self {
OpenOptions(fs_imp::OpenOptions::new())
}
/// Sets the option for read access.
///
/// This option, when true, will indicate that the file should be
/// `read`-able if opened.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().read(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn read(&mut self, read: bool) -> &mut Self {
self.0.read(read);
self
}
/// Sets the option for write access.
///
/// This option, when true, will indicate that the file should be
/// `write`-able if opened.
///
/// If the file already exists, any write calls on it will overwrite its
/// contents, without truncating it.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().write(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn write(&mut self, write: bool) -> &mut Self {
self.0.write(write);
self
}
/// Sets the option for the append mode.
///
/// This option, when true, means that writes will append to a file instead
/// of overwriting previous contents.
/// Note that setting `.write(true).append(true)` has the same effect as
/// setting only `.append(true)`.
///
/// Append mode guarantees that writes will be positioned at the current end of file,
/// even when there are other processes or threads appending to the same file. This is
/// unlike <code>[seek]\([SeekFrom]::[End]\(0))</code> followed by `write()`, which
/// has a race between seeking and writing during which another writer can write, with
/// our `write()` overwriting their data.
///
/// Keep in mind that this does not necessarily guarantee that data appended by
/// different processes or threads does not interleave. The amount of data accepted a
/// single `write()` call depends on the operating system and file system. A
/// successful `write()` is allowed to write only part of the given data, so even if
/// you're careful to provide the whole message in a single call to `write()`, there
/// is no guarantee that it will be written out in full. If you rely on the filesystem
/// accepting the message in a single write, make sure that all data that belongs
/// together is written in one operation. This can be done by concatenating strings
/// before passing them to [`write()`].
///
/// If a file is opened with both read and append access, beware that after
/// opening, and after every write, the position for reading may be set at the
/// end of the file. So, before writing, save the current position (using
/// <code>[Seek]::[stream_position]</code>), and restore it before the next read.
///
/// ## Note
///
/// This function doesn't create the file if it doesn't exist. Use the
/// [`OpenOptions::create`] method to do so.
///
/// [`write()`]: Write::write "io::Write::write"
/// [`flush()`]: Write::flush "io::Write::flush"
/// [stream_position]: Seek::stream_position "io::Seek::stream_position"
/// [seek]: Seek::seek "io::Seek::seek"
/// [Current]: SeekFrom::Current "io::SeekFrom::Current"
/// [End]: SeekFrom::End "io::SeekFrom::End"
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().append(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn append(&mut self, append: bool) -> &mut Self {
self.0.append(append);
self
}
/// Sets the option for truncating a previous file.
///
/// If a file is successfully opened with this option set it will truncate
/// the file to 0 length if it already exists.
///
/// The file must be opened with write access for truncate to work.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().write(true).truncate(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn truncate(&mut self, truncate: bool) -> &mut Self {
self.0.truncate(truncate);
self
}
/// Sets the option to create a new file, or open it if it already exists.
///
/// In order for the file to be created, [`OpenOptions::write`] or
/// [`OpenOptions::append`] access must be used.
///
/// See also [`std::fs::write()`][self::write] for a simple function to
/// create a file with some given data.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().write(true).create(true).open("foo.txt");
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn create(&mut self, create: bool) -> &mut Self {
self.0.create(create);
self
}
/// Sets the option to create a new file, failing if it already exists.
///
/// No file is allowed to exist at the target location, also no (dangling) symlink. In this
/// way, if the call succeeds, the file returned is guaranteed to be new.
/// If a file exists at the target location, creating a new file will fail with [`AlreadyExists`]
/// or another error based on the situation. See [`OpenOptions::open`] for a
/// non-exhaustive list of likely errors.
///
/// This option is useful because it is atomic. Otherwise between checking
/// whether a file exists and creating a new one, the file may have been
/// created by another process (a TOCTOU race condition / attack).
///
/// If `.create_new(true)` is set, [`.create()`] and [`.truncate()`] are
/// ignored.
///
/// The file must be opened with write or append access in order to create
/// a new file.
///
/// [`.create()`]: OpenOptions::create
/// [`.truncate()`]: OpenOptions::truncate
/// [`AlreadyExists`]: io::ErrorKind::AlreadyExists
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().write(true)
/// .create_new(true)
/// .open("foo.txt");
/// ```
#[stable(feature = "expand_open_options2", since = "1.9.0")]
pub fn create_new(&mut self, create_new: bool) -> &mut Self {
self.0.create_new(create_new);
self
}
/// Opens a file at `path` with the options specified by `self`.
///
/// # Errors
///
/// This function will return an error under a number of different
/// circumstances. Some of these error conditions are listed here, together
/// with their [`io::ErrorKind`]. The mapping to [`io::ErrorKind`]s is not
/// part of the compatibility contract of the function.
///
/// * [`NotFound`]: The specified file does not exist and neither `create`
/// or `create_new` is set.
/// * [`NotFound`]: One of the directory components of the file path does
/// not exist.
/// * [`PermissionDenied`]: The user lacks permission to get the specified
/// access rights for the file.
/// * [`PermissionDenied`]: The user lacks permission to open one of the
/// directory components of the specified path.
/// * [`AlreadyExists`]: `create_new` was specified and the file already
/// exists.
/// * [`InvalidInput`]: Invalid combinations of open options (truncate
/// without write access, no access mode set, etc.).
///
/// The following errors don't match any existing [`io::ErrorKind`] at the moment:
/// * One of the directory components of the specified file path
/// was not, in fact, a directory.
/// * Filesystem-level errors: full disk, write permission
/// requested on a read-only file system, exceeded disk quota, too many
/// open files, too long filename, too many symbolic links in the
/// specified path (Unix-like systems only), etc.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
///
/// let file = OpenOptions::new().read(true).open("foo.txt");
/// ```
///
/// [`AlreadyExists`]: io::ErrorKind::AlreadyExists
/// [`InvalidInput`]: io::ErrorKind::InvalidInput
/// [`NotFound`]: io::ErrorKind::NotFound
/// [`PermissionDenied`]: io::ErrorKind::PermissionDenied
#[stable(feature = "rust1", since = "1.0.0")]
pub fn open<P: AsRef<Path>>(&self, path: P) -> io::Result<File> {
self._open(path.as_ref())
}
fn _open(&self, path: &Path) -> io::Result<File> {
fs_imp::File::open(path, &self.0).map(|inner| File { inner })
}
}
impl AsInner<fs_imp::OpenOptions> for OpenOptions {
#[inline]
fn as_inner(&self) -> &fs_imp::OpenOptions {
&self.0
}
}
impl AsInnerMut<fs_imp::OpenOptions> for OpenOptions {
#[inline]
fn as_inner_mut(&mut self) -> &mut fs_imp::OpenOptions {
&mut self.0
}
}
impl Metadata {
/// Returns the file type for this metadata.
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs;
///
/// let metadata = fs::metadata("foo.txt")?;
///
/// println!("{:?}", metadata.file_type());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "file_type", since = "1.1.0")]
pub fn file_type(&self) -> FileType {
FileType(self.0.file_type())
}
/// Returns `true` if this metadata is for a directory. The
/// result is mutually exclusive to the result of
/// [`Metadata::is_file`], and will be false for symlink metadata
/// obtained from [`symlink_metadata`].
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs;
///
/// let metadata = fs::metadata("foo.txt")?;
///
/// assert!(!metadata.is_dir());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn is_dir(&self) -> bool {
self.file_type().is_dir()
}
/// Returns `true` if this metadata is for a regular file. The
/// result is mutually exclusive to the result of
/// [`Metadata::is_dir`], and will be false for symlink metadata
/// obtained from [`symlink_metadata`].
///
/// When the goal is simply to read from (or write to) the source, the most
/// reliable way to test the source can be read (or written to) is to open
/// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
/// a Unix-like system for example. See [`File::open`] or
/// [`OpenOptions::open`] for more information.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// assert!(metadata.is_file());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn is_file(&self) -> bool {
self.file_type().is_file()
}
/// Returns `true` if this metadata is for a symbolic link.
///
/// # Examples
///
#[cfg_attr(unix, doc = "```no_run")]
#[cfg_attr(not(unix), doc = "```ignore")]
/// use std::fs;
/// use std::path::Path;
/// use std::os::unix::fs::symlink;
///
/// fn main() -> std::io::Result<()> {
/// let link_path = Path::new("link");
/// symlink("/origin_does_not_exist/", link_path)?;
///
/// let metadata = fs::symlink_metadata(link_path)?;
///
/// assert!(metadata.is_symlink());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "is_symlink", since = "1.58.0")]
pub fn is_symlink(&self) -> bool {
self.file_type().is_symlink()
}
/// Returns the size of the file, in bytes, this metadata is for.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// assert_eq!(0, metadata.len());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn len(&self) -> u64 {
self.0.size()
}
/// Returns the permissions of the file this metadata is for.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// assert!(!metadata.permissions().readonly());
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn permissions(&self) -> Permissions {
Permissions(self.0.perm())
}
/// Returns the last modification time listed in this metadata.
///
/// The returned value corresponds to the `mtime` field of `stat` on Unix
/// platforms and the `ftLastWriteTime` field on Windows platforms.
///
/// # Errors
///
/// This field might not be available on all platforms, and will return an
/// `Err` on platforms where it is not available.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// if let Ok(time) = metadata.modified() {
/// println!("{time:?}");
/// } else {
/// println!("Not supported on this platform");
/// }
/// Ok(())
/// }
/// ```
#[doc(alias = "mtime", alias = "ftLastWriteTime")]
#[stable(feature = "fs_time", since = "1.10.0")]
pub fn modified(&self) -> io::Result<SystemTime> {
self.0.modified().map(FromInner::from_inner)
}
/// Returns the last access time of this metadata.
///
/// The returned value corresponds to the `atime` field of `stat` on Unix
/// platforms and the `ftLastAccessTime` field on Windows platforms.
///
/// Note that not all platforms will keep this field update in a file's
/// metadata, for example Windows has an option to disable updating this
/// time when files are accessed and Linux similarly has `noatime`.
///
/// # Errors
///
/// This field might not be available on all platforms, and will return an
/// `Err` on platforms where it is not available.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// if let Ok(time) = metadata.accessed() {
/// println!("{time:?}");
/// } else {
/// println!("Not supported on this platform");
/// }
/// Ok(())
/// }
/// ```
#[doc(alias = "atime", alias = "ftLastAccessTime")]
#[stable(feature = "fs_time", since = "1.10.0")]
pub fn accessed(&self) -> io::Result<SystemTime> {
self.0.accessed().map(FromInner::from_inner)
}
/// Returns the creation time listed in this metadata.
///
/// The returned value corresponds to the `btime` field of `statx` on
/// Linux kernel starting from to 4.11, the `birthtime` field of `stat` on other
/// Unix platforms, and the `ftCreationTime` field on Windows platforms.
///
/// # Errors
///
/// This field might not be available on all platforms, and will return an
/// `Err` on platforms or filesystems where it is not available.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
///
/// if let Ok(time) = metadata.created() {
/// println!("{time:?}");
/// } else {
/// println!("Not supported on this platform or filesystem");
/// }
/// Ok(())
/// }
/// ```
#[doc(alias = "btime", alias = "birthtime", alias = "ftCreationTime")]
#[stable(feature = "fs_time", since = "1.10.0")]
pub fn created(&self) -> io::Result<SystemTime> {
self.0.created().map(FromInner::from_inner)
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for Metadata {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
let mut debug = f.debug_struct("Metadata");
debug.field("file_type", &self.file_type());
debug.field("permissions", &self.permissions());
debug.field("len", &self.len());
if let Ok(modified) = self.modified() {
debug.field("modified", &modified);
}
if let Ok(accessed) = self.accessed() {
debug.field("accessed", &accessed);
}
if let Ok(created) = self.created() {
debug.field("created", &created);
}
debug.finish_non_exhaustive()
}
}
impl AsInner<fs_imp::FileAttr> for Metadata {
#[inline]
fn as_inner(&self) -> &fs_imp::FileAttr {
&self.0
}
}
impl FromInner<fs_imp::FileAttr> for Metadata {
fn from_inner(attr: fs_imp::FileAttr) -> Metadata {
Metadata(attr)
}
}
impl FileTimes {
/// Creates a new `FileTimes` with no times set.
///
/// Using the resulting `FileTimes` in [`File::set_times`] will not modify any timestamps.
#[stable(feature = "file_set_times", since = "1.75.0")]
pub fn new() -> Self {
Self::default()
}
/// Set the last access time of a file.
#[stable(feature = "file_set_times", since = "1.75.0")]
pub fn set_accessed(mut self, t: SystemTime) -> Self {
self.0.set_accessed(t.into_inner());
self
}
/// Set the last modified time of a file.
#[stable(feature = "file_set_times", since = "1.75.0")]
pub fn set_modified(mut self, t: SystemTime) -> Self {
self.0.set_modified(t.into_inner());
self
}
}
impl AsInnerMut<fs_imp::FileTimes> for FileTimes {
fn as_inner_mut(&mut self) -> &mut fs_imp::FileTimes {
&mut self.0
}
}
// For implementing OS extension traits in `std::os`
#[stable(feature = "file_set_times", since = "1.75.0")]
impl Sealed for FileTimes {}
impl Permissions {
/// Returns `true` if these permissions describe a readonly (unwritable) file.
///
/// # Note
///
/// This function does not take Access Control Lists (ACLs) or Unix group
/// membership into account.
///
/// # Windows
///
/// On Windows this returns [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
/// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
/// but the user may still have permission to change this flag. If
/// `FILE_ATTRIBUTE_READONLY` is *not* set then writes may still fail due
/// to lack of write permission.
/// The behavior of this attribute for directories depends on the Windows
/// version.
///
/// # Unix (including macOS)
///
/// On Unix-based platforms this checks if *any* of the owner, group or others
/// write permission bits are set. It does not check if the current
/// user is in the file's assigned group. It also does not check ACLs.
/// Therefore the return value of this function cannot be relied upon
/// to predict whether attempts to read or write the file will actually succeed.
/// The [`PermissionsExt`] trait gives direct access to the permission bits but
/// also does not read ACLs.
///
/// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let mut f = File::create("foo.txt")?;
/// let metadata = f.metadata()?;
///
/// assert_eq!(false, metadata.permissions().readonly());
/// Ok(())
/// }
/// ```
#[must_use = "call `set_readonly` to modify the readonly flag"]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn readonly(&self) -> bool {
self.0.readonly()
}
/// Modifies the readonly flag for this set of permissions. If the
/// `readonly` argument is `true`, using the resulting `Permission` will
/// update file permissions to forbid writing. Conversely, if it's `false`,
/// using the resulting `Permission` will update file permissions to allow
/// writing.
///
/// This operation does **not** modify the files attributes. This only
/// changes the in-memory value of these attributes for this `Permissions`
/// instance. To modify the files attributes use the [`set_permissions`]
/// function which commits these attribute changes to the file.
///
/// # Note
///
/// `set_readonly(false)` makes the file *world-writable* on Unix.
/// You can use the [`PermissionsExt`] trait on Unix to avoid this issue.
///
/// It also does not take Access Control Lists (ACLs) or Unix group
/// membership into account.
///
/// # Windows
///
/// On Windows this sets or clears [`FILE_ATTRIBUTE_READONLY`](https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants).
/// If `FILE_ATTRIBUTE_READONLY` is set then writes to the file will fail
/// but the user may still have permission to change this flag. If
/// `FILE_ATTRIBUTE_READONLY` is *not* set then the write may still fail if
/// the user does not have permission to write to the file.
///
/// In Windows 7 and earlier this attribute prevents deleting empty
/// directories. It does not prevent modifying the directory contents.
/// On later versions of Windows this attribute is ignored for directories.
///
/// # Unix (including macOS)
///
/// On Unix-based platforms this sets or clears the write access bit for
/// the owner, group *and* others, equivalent to `chmod a+w <file>`
/// or `chmod a-w <file>` respectively. The latter will grant write access
/// to all users! You can use the [`PermissionsExt`] trait on Unix
/// to avoid this issue.
///
/// [`PermissionsExt`]: crate::os::unix::fs::PermissionsExt
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
///
/// fn main() -> std::io::Result<()> {
/// let f = File::create("foo.txt")?;
/// let metadata = f.metadata()?;
/// let mut permissions = metadata.permissions();
///
/// permissions.set_readonly(true);
///
/// // filesystem doesn't change, only the in memory state of the
/// // readonly permission
/// assert_eq!(false, metadata.permissions().readonly());
///
/// // just this particular `permissions`.
/// assert_eq!(true, permissions.readonly());
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn set_readonly(&mut self, readonly: bool) {
self.0.set_readonly(readonly)
}
}
impl FileType {
/// Tests whether this file type represents a directory. The
/// result is mutually exclusive to the results of
/// [`is_file`] and [`is_symlink`]; only zero or one of these
/// tests may pass.
///
/// [`is_file`]: FileType::is_file
/// [`is_symlink`]: FileType::is_symlink
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs;
///
/// let metadata = fs::metadata("foo.txt")?;
/// let file_type = metadata.file_type();
///
/// assert_eq!(file_type.is_dir(), false);
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "file_type", since = "1.1.0")]
pub fn is_dir(&self) -> bool {
self.0.is_dir()
}
/// Tests whether this file type represents a regular file.
/// The result is mutually exclusive to the results of
/// [`is_dir`] and [`is_symlink`]; only zero or one of these
/// tests may pass.
///
/// When the goal is simply to read from (or write to) the source, the most
/// reliable way to test the source can be read (or written to) is to open
/// it. Only using `is_file` can break workflows like `diff <( prog_a )` on
/// a Unix-like system for example. See [`File::open`] or
/// [`OpenOptions::open`] for more information.
///
/// [`is_dir`]: FileType::is_dir
/// [`is_symlink`]: FileType::is_symlink
///
/// # Examples
///
/// ```no_run
/// fn main() -> std::io::Result<()> {
/// use std::fs;
///
/// let metadata = fs::metadata("foo.txt")?;
/// let file_type = metadata.file_type();
///
/// assert_eq!(file_type.is_file(), true);
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "file_type", since = "1.1.0")]
pub fn is_file(&self) -> bool {
self.0.is_file()
}
/// Tests whether this file type represents a symbolic link.
/// The result is mutually exclusive to the results of
/// [`is_dir`] and [`is_file`]; only zero or one of these
/// tests may pass.
///
/// The underlying [`Metadata`] struct needs to be retrieved
/// with the [`fs::symlink_metadata`] function and not the
/// [`fs::metadata`] function. The [`fs::metadata`] function
/// follows symbolic links, so [`is_symlink`] would always
/// return `false` for the target file.
///
/// [`fs::metadata`]: metadata
/// [`fs::symlink_metadata`]: symlink_metadata
/// [`is_dir`]: FileType::is_dir
/// [`is_file`]: FileType::is_file
/// [`is_symlink`]: FileType::is_symlink
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let metadata = fs::symlink_metadata("foo.txt")?;
/// let file_type = metadata.file_type();
///
/// assert_eq!(file_type.is_symlink(), false);
/// Ok(())
/// }
/// ```
#[must_use]
#[stable(feature = "file_type", since = "1.1.0")]
pub fn is_symlink(&self) -> bool {
self.0.is_symlink()
}
}
#[stable(feature = "std_debug", since = "1.16.0")]
impl fmt::Debug for FileType {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("FileType")
.field("is_file", &self.is_file())
.field("is_dir", &self.is_dir())
.field("is_symlink", &self.is_symlink())
.finish_non_exhaustive()
}
}
impl AsInner<fs_imp::FileType> for FileType {
#[inline]
fn as_inner(&self) -> &fs_imp::FileType {
&self.0
}
}
impl FromInner<fs_imp::FilePermissions> for Permissions {
fn from_inner(f: fs_imp::FilePermissions) -> Permissions {
Permissions(f)
}
}
impl AsInner<fs_imp::FilePermissions> for Permissions {
#[inline]
fn as_inner(&self) -> &fs_imp::FilePermissions {
&self.0
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl Iterator for ReadDir {
type Item = io::Result<DirEntry>;
fn next(&mut self) -> Option<io::Result<DirEntry>> {
self.0.next().map(|entry| entry.map(DirEntry))
}
}
impl DirEntry {
/// Returns the full path to the file that this entry represents.
///
/// The full path is created by joining the original path to `read_dir`
/// with the filename of this entry.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// for entry in fs::read_dir(".")? {
/// let dir = entry?;
/// println!("{:?}", dir.path());
/// }
/// Ok(())
/// }
/// ```
///
/// This prints output like:
///
/// ```text
/// "./whatever.txt"
/// "./foo.html"
/// "./hello_world.rs"
/// ```
///
/// The exact text, of course, depends on what files you have in `.`.
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn path(&self) -> PathBuf {
self.0.path()
}
/// Returns the metadata for the file that this entry points at.
///
/// This function will not traverse symlinks if this entry points at a
/// symlink. To traverse symlinks use [`fs::metadata`] or [`fs::File::metadata`].
///
/// [`fs::metadata`]: metadata
/// [`fs::File::metadata`]: File::metadata
///
/// # Platform-specific behavior
///
/// On Windows this function is cheap to call (no extra system calls
/// needed), but on Unix platforms this function is the equivalent of
/// calling `symlink_metadata` on the path.
///
/// # Examples
///
/// ```
/// use std::fs;
///
/// if let Ok(entries) = fs::read_dir(".") {
/// for entry in entries {
/// if let Ok(entry) = entry {
/// // Here, `entry` is a `DirEntry`.
/// if let Ok(metadata) = entry.metadata() {
/// // Now let's show our entry's permissions!
/// println!("{:?}: {:?}", entry.path(), metadata.permissions());
/// } else {
/// println!("Couldn't get metadata for {:?}", entry.path());
/// }
/// }
/// }
/// }
/// ```
#[stable(feature = "dir_entry_ext", since = "1.1.0")]
pub fn metadata(&self) -> io::Result<Metadata> {
self.0.metadata().map(Metadata)
}
/// Returns the file type for the file that this entry points at.
///
/// This function will not traverse symlinks if this entry points at a
/// symlink.
///
/// # Platform-specific behavior
///
/// On Windows and most Unix platforms this function is free (no extra
/// system calls needed), but some Unix platforms may require the equivalent
/// call to `symlink_metadata` to learn about the target file type.
///
/// # Examples
///
/// ```
/// use std::fs;
///
/// if let Ok(entries) = fs::read_dir(".") {
/// for entry in entries {
/// if let Ok(entry) = entry {
/// // Here, `entry` is a `DirEntry`.
/// if let Ok(file_type) = entry.file_type() {
/// // Now let's show our entry's file type!
/// println!("{:?}: {:?}", entry.path(), file_type);
/// } else {
/// println!("Couldn't get file type for {:?}", entry.path());
/// }
/// }
/// }
/// }
/// ```
#[stable(feature = "dir_entry_ext", since = "1.1.0")]
pub fn file_type(&self) -> io::Result<FileType> {
self.0.file_type().map(FileType)
}
/// Returns the file name of this directory entry without any
/// leading path component(s).
///
/// As an example,
/// the output of the function will result in "foo" for all the following paths:
/// - "./foo"
/// - "/the/foo"
/// - "../../foo"
///
/// # Examples
///
/// ```
/// use std::fs;
///
/// if let Ok(entries) = fs::read_dir(".") {
/// for entry in entries {
/// if let Ok(entry) = entry {
/// // Here, `entry` is a `DirEntry`.
/// println!("{:?}", entry.file_name());
/// }
/// }
/// }
/// ```
#[must_use]
#[stable(feature = "dir_entry_ext", since = "1.1.0")]
pub fn file_name(&self) -> OsString {
self.0.file_name()
}
}
#[stable(feature = "dir_entry_debug", since = "1.13.0")]
impl fmt::Debug for DirEntry {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_tuple("DirEntry").field(&self.path()).finish()
}
}
impl AsInner<fs_imp::DirEntry> for DirEntry {
#[inline]
fn as_inner(&self) -> &fs_imp::DirEntry {
&self.0
}
}
/// Removes a file from the filesystem.
///
/// Note that there is no
/// guarantee that the file is immediately deleted (e.g., depending on
/// platform, other open file descriptors may prevent immediate removal).
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `unlink` function on Unix
/// and the `DeleteFile` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `path` points to a directory.
/// * The file doesn't exist.
/// * The user lacks permissions to remove the file.
///
/// This function will only ever return an error of kind `NotFound` if the given
/// path does not exist. Note that the inverse is not true,
/// ie. if a path does not exist, its removal may fail for a number of reasons,
/// such as insufficient permissions.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::remove_file("a.txt")?;
/// Ok(())
/// }
/// ```
#[doc(alias = "rm", alias = "unlink", alias = "DeleteFile")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn remove_file<P: AsRef<Path>>(path: P) -> io::Result<()> {
fs_imp::unlink(path.as_ref())
}
/// Given a path, queries the file system to get information about a file,
/// directory, etc.
///
/// This function will traverse symbolic links to query information about the
/// destination file.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `stat` function on Unix
/// and the `GetFileInformationByHandle` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * The user lacks permissions to perform `metadata` call on `path`.
/// * `path` does not exist.
///
/// # Examples
///
/// ```rust,no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let attr = fs::metadata("/some/file/path.txt")?;
/// // inspect attr ...
/// Ok(())
/// }
/// ```
#[doc(alias = "stat")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
fs_imp::stat(path.as_ref()).map(Metadata)
}
/// Queries the metadata about a file without following symlinks.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `lstat` function on Unix
/// and the `GetFileInformationByHandle` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * The user lacks permissions to perform `metadata` call on `path`.
/// * `path` does not exist.
///
/// # Examples
///
/// ```rust,no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let attr = fs::symlink_metadata("/some/file/path.txt")?;
/// // inspect attr ...
/// Ok(())
/// }
/// ```
#[doc(alias = "lstat")]
#[stable(feature = "symlink_metadata", since = "1.1.0")]
pub fn symlink_metadata<P: AsRef<Path>>(path: P) -> io::Result<Metadata> {
fs_imp::lstat(path.as_ref()).map(Metadata)
}
/// Renames a file or directory to a new name, replacing the original file if
/// `to` already exists.
///
/// This will not work if the new name is on a different mount point.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `rename` function on Unix
/// and the `MoveFileEx` function with the `MOVEFILE_REPLACE_EXISTING` flag on Windows.
///
/// Because of this, the behavior when both `from` and `to` exist differs. On
/// Unix, if `from` is a directory, `to` must also be an (empty) directory. If
/// `from` is not a directory, `to` must also be not a directory. In contrast,
/// on Windows, `from` can be anything, but `to` must *not* be a directory.
///
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `from` does not exist.
/// * The user lacks permissions to view contents.
/// * `from` and `to` are on separate filesystems.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::rename("a.txt", "b.txt")?; // Rename a.txt to b.txt
/// Ok(())
/// }
/// ```
#[doc(alias = "mv", alias = "MoveFile", alias = "MoveFileEx")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn rename<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<()> {
fs_imp::rename(from.as_ref(), to.as_ref())
}
/// Copies the contents of one file to another. This function will also
/// copy the permission bits of the original file to the destination file.
///
/// This function will **overwrite** the contents of `to`.
///
/// Note that if `from` and `to` both point to the same file, then the file
/// will likely get truncated by this operation.
///
/// On success, the total number of bytes copied is returned and it is equal to
/// the length of the `to` file as reported by `metadata`.
///
/// If you want to copy the contents of one file to another and you’re
/// working with [`File`]s, see the [`io::copy`](io::copy()) function.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `open` function in Unix
/// with `O_RDONLY` for `from` and `O_WRONLY`, `O_CREAT`, and `O_TRUNC` for `to`.
/// `O_CLOEXEC` is set for returned file descriptors.
///
/// On Linux (including Android), this function attempts to use `copy_file_range(2)`,
/// and falls back to reading and writing if that is not possible.
///
/// On Windows, this function currently corresponds to `CopyFileEx`. Alternate
/// NTFS streams are copied but only the size of the main stream is returned by
/// this function.
///
/// On MacOS, this function corresponds to `fclonefileat` and `fcopyfile`.
///
/// Note that platform-specific behavior [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `from` is neither a regular file nor a symlink to a regular file.
/// * `from` does not exist.
/// * The current process does not have the permission rights to read
/// `from` or write `to`.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::copy("foo.txt", "bar.txt")?; // Copy foo.txt to bar.txt
/// Ok(())
/// }
/// ```
#[doc(alias = "cp")]
#[doc(alias = "CopyFile", alias = "CopyFileEx")]
#[doc(alias = "fclonefileat", alias = "fcopyfile")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn copy<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> io::Result<u64> {
fs_imp::copy(from.as_ref(), to.as_ref())
}
/// Creates a new hard link on the filesystem.
///
/// The `link` path will be a link pointing to the `original` path. Note that
/// systems often require these two paths to both be located on the same
/// filesystem.
///
/// If `original` names a symbolic link, it is platform-specific whether the
/// symbolic link is followed. On platforms where it's possible to not follow
/// it, it is not followed, and the created hard link points to the symbolic
/// link itself.
///
/// # Platform-specific behavior
///
/// This function currently corresponds the `CreateHardLink` function on Windows.
/// On most Unix systems, it corresponds to the `linkat` function with no flags.
/// On Android, VxWorks, and Redox, it instead corresponds to the `link` function.
/// On MacOS, it uses the `linkat` function if it is available, but on very old
/// systems where `linkat` is not available, `link` is selected at runtime instead.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * The `original` path is not a file or doesn't exist.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::hard_link("a.txt", "b.txt")?; // Hard link a.txt to b.txt
/// Ok(())
/// }
/// ```
#[doc(alias = "CreateHardLink", alias = "linkat")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
fs_imp::link(original.as_ref(), link.as_ref())
}
/// Creates a new symbolic link on the filesystem.
///
/// The `link` path will be a symbolic link pointing to the `original` path.
/// On Windows, this will be a file symlink, not a directory symlink;
/// for this reason, the platform-specific [`std::os::unix::fs::symlink`]
/// and [`std::os::windows::fs::symlink_file`] or [`symlink_dir`] should be
/// used instead to make the intent explicit.
///
/// [`std::os::unix::fs::symlink`]: crate::os::unix::fs::symlink
/// [`std::os::windows::fs::symlink_file`]: crate::os::windows::fs::symlink_file
/// [`symlink_dir`]: crate::os::windows::fs::symlink_dir
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::soft_link("a.txt", "b.txt")?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[deprecated(
since = "1.1.0",
note = "replaced with std::os::unix::fs::symlink and \
std::os::windows::fs::{symlink_file, symlink_dir}"
)]
pub fn soft_link<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
fs_imp::symlink(original.as_ref(), link.as_ref())
}
/// Reads a symbolic link, returning the file that the link points to.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `readlink` function on Unix
/// and the `CreateFile` function with `FILE_FLAG_OPEN_REPARSE_POINT` and
/// `FILE_FLAG_BACKUP_SEMANTICS` flags on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `path` is not a symbolic link.
/// * `path` does not exist.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let path = fs::read_link("a.txt")?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn read_link<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
fs_imp::readlink(path.as_ref())
}
/// Returns the canonical, absolute form of a path with all intermediate
/// components normalized and symbolic links resolved.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `realpath` function on Unix
/// and the `CreateFile` and `GetFinalPathNameByHandle` functions on Windows.
/// Note that this [may change in the future][changes].
///
/// On Windows, this converts the path to use [extended length path][path]
/// syntax, which allows your program to use longer path names, but means you
/// can only join backslash-delimited paths to it, and it may be incompatible
/// with other applications (if passed to the application on the command-line,
/// or written to a file another application may read).
///
/// [changes]: io#platform-specific-behavior
/// [path]: https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `path` does not exist.
/// * A non-final component in path is not a directory.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let path = fs::canonicalize("../a/../foo.txt")?;
/// Ok(())
/// }
/// ```
#[doc(alias = "realpath")]
#[doc(alias = "GetFinalPathNameByHandle")]
#[stable(feature = "fs_canonicalize", since = "1.5.0")]
pub fn canonicalize<P: AsRef<Path>>(path: P) -> io::Result<PathBuf> {
fs_imp::canonicalize(path.as_ref())
}
/// Creates a new, empty directory at the provided path
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `mkdir` function on Unix
/// and the `CreateDirectoryW` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// **NOTE**: If a parent of the given path doesn't exist, this function will
/// return an error. To create a directory and all its missing parents at the
/// same time, use the [`create_dir_all`] function.
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * User lacks permissions to create directory at `path`.
/// * A parent of the given path doesn't exist. (To create a directory and all
/// its missing parents at the same time, use the [`create_dir_all`]
/// function.)
/// * `path` already exists.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::create_dir("/some/dir")?;
/// Ok(())
/// }
/// ```
#[doc(alias = "mkdir", alias = "CreateDirectory")]
#[stable(feature = "rust1", since = "1.0.0")]
#[cfg_attr(not(test), rustc_diagnostic_item = "fs_create_dir")]
pub fn create_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
DirBuilder::new().create(path.as_ref())
}
/// Recursively create a directory and all of its parent components if they
/// are missing.
///
/// If this function returns an error, some of the parent components might have
/// been created already.
///
/// If the empty path is passed to this function, it always succeeds without
/// creating any directories.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to multiple calls to the `mkdir`
/// function on Unix and the `CreateDirectoryW` function on Windows.
///
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// The function will return an error if any directory specified in path does not exist and
/// could not be created. There may be other error conditions; see [`fs::create_dir`] for specifics.
///
/// Notable exception is made for situations where any of the directories
/// specified in the `path` could not be created as it was being created concurrently.
/// Such cases are considered to be successful. That is, calling `create_dir_all`
/// concurrently from multiple threads or processes is guaranteed not to fail
/// due to a race condition with itself.
///
/// [`fs::create_dir`]: create_dir
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::create_dir_all("/some/dir")?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn create_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
DirBuilder::new().recursive(true).create(path.as_ref())
}
/// Removes an empty directory.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `rmdir` function on Unix
/// and the `RemoveDirectory` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `path` doesn't exist.
/// * `path` isn't a directory.
/// * The user lacks permissions to remove the directory at the provided `path`.
/// * The directory isn't empty.
///
/// This function will only ever return an error of kind `NotFound` if the given
/// path does not exist. Note that the inverse is not true,
/// ie. if a path does not exist, its removal may fail for a number of reasons,
/// such as insufficient permissions.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::remove_dir("/some/dir")?;
/// Ok(())
/// }
/// ```
#[doc(alias = "rmdir", alias = "RemoveDirectory")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn remove_dir<P: AsRef<Path>>(path: P) -> io::Result<()> {
fs_imp::rmdir(path.as_ref())
}
/// Removes a directory at this path, after removing all its contents. Use
/// carefully!
///
/// This function does **not** follow symbolic links and it will simply remove the
/// symbolic link itself.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to `openat`, `fdopendir`, `unlinkat` and `lstat` functions
/// on Unix (except for REDOX) and the `CreateFileW`, `GetFileInformationByHandleEx`,
/// `SetFileInformationByHandle`, and `NtCreateFile` functions on Windows. Note that, this
/// [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// On REDOX, as well as when running in Miri for any target, this function is not protected against
/// time-of-check to time-of-use (TOCTOU) race conditions, and should not be used in
/// security-sensitive code on those platforms. All other platforms are protected.
///
/// # Errors
///
/// See [`fs::remove_file`] and [`fs::remove_dir`].
///
/// `remove_dir_all` will fail if `remove_dir` or `remove_file` fail on any constituent paths, including the root path.
/// As a result, the directory you are deleting must exist, meaning that this function is not idempotent.
///
/// Consider ignoring the error if validating the removal is not required for your use case.
///
/// [`io::ErrorKind::NotFound`] is only returned if no removal occurs.
///
/// [`fs::remove_file`]: remove_file
/// [`fs::remove_dir`]: remove_dir
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::remove_dir_all("/some/dir")?;
/// Ok(())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn remove_dir_all<P: AsRef<Path>>(path: P) -> io::Result<()> {
fs_imp::remove_dir_all(path.as_ref())
}
/// Returns an iterator over the entries within a directory.
///
/// The iterator will yield instances of <code>[io::Result]<[DirEntry]></code>.
/// New errors may be encountered after an iterator is initially constructed.
/// Entries for the current and parent directories (typically `.` and `..`) are
/// skipped.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `opendir` function on Unix
/// and the `FindFirstFile` function on Windows. Advancing the iterator
/// currently corresponds to `readdir` on Unix and `FindNextFile` on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// The order in which this iterator returns entries is platform and filesystem
/// dependent.
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * The provided `path` doesn't exist.
/// * The process lacks permissions to view the contents.
/// * The `path` points at a non-directory file.
///
/// # Examples
///
/// ```
/// use std::io;
/// use std::fs::{self, DirEntry};
/// use std::path::Path;
///
/// // one possible implementation of walking a directory only visiting files
/// fn visit_dirs(dir: &Path, cb: &dyn Fn(&DirEntry)) -> io::Result<()> {
/// if dir.is_dir() {
/// for entry in fs::read_dir(dir)? {
/// let entry = entry?;
/// let path = entry.path();
/// if path.is_dir() {
/// visit_dirs(&path, cb)?;
/// } else {
/// cb(&entry);
/// }
/// }
/// }
/// Ok(())
/// }
/// ```
///
/// ```rust,no_run
/// use std::{fs, io};
///
/// fn main() -> io::Result<()> {
/// let mut entries = fs::read_dir(".")?
/// .map(|res| res.map(|e| e.path()))
/// .collect::<Result<Vec<_>, io::Error>>()?;
///
/// // The order in which `read_dir` returns entries is not guaranteed. If reproducible
/// // ordering is required the entries should be explicitly sorted.
///
/// entries.sort();
///
/// // The entries have now been sorted by their path.
///
/// Ok(())
/// }
/// ```
#[doc(alias = "ls", alias = "opendir", alias = "FindFirstFile", alias = "FindNextFile")]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn read_dir<P: AsRef<Path>>(path: P) -> io::Result<ReadDir> {
fs_imp::readdir(path.as_ref()).map(ReadDir)
}
/// Changes the permissions found on a file or a directory.
///
/// # Platform-specific behavior
///
/// This function currently corresponds to the `chmod` function on Unix
/// and the `SetFileAttributes` function on Windows.
/// Note that, this [may change in the future][changes].
///
/// [changes]: io#platform-specific-behavior
///
/// # Errors
///
/// This function will return an error in the following situations, but is not
/// limited to just these cases:
///
/// * `path` does not exist.
/// * The user lacks the permission to change attributes of the file.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// fn main() -> std::io::Result<()> {
/// let mut perms = fs::metadata("foo.txt")?.permissions();
/// perms.set_readonly(true);
/// fs::set_permissions("foo.txt", perms)?;
/// Ok(())
/// }
/// ```
#[doc(alias = "chmod", alias = "SetFileAttributes")]
#[stable(feature = "set_permissions", since = "1.1.0")]
pub fn set_permissions<P: AsRef<Path>>(path: P, perm: Permissions) -> io::Result<()> {
fs_imp::set_perm(path.as_ref(), perm.0)
}
impl DirBuilder {
/// Creates a new set of options with default mode/security settings for all
/// platforms and also non-recursive.
///
/// # Examples
///
/// ```
/// use std::fs::DirBuilder;
///
/// let builder = DirBuilder::new();
/// ```
#[stable(feature = "dir_builder", since = "1.6.0")]
#[must_use]
pub fn new() -> DirBuilder {
DirBuilder { inner: fs_imp::DirBuilder::new(), recursive: false }
}
/// Indicates that directories should be created recursively, creating all
/// parent directories. Parents that do not exist are created with the same
/// security and permissions settings.
///
/// This option defaults to `false`.
///
/// # Examples
///
/// ```
/// use std::fs::DirBuilder;
///
/// let mut builder = DirBuilder::new();
/// builder.recursive(true);
/// ```
#[stable(feature = "dir_builder", since = "1.6.0")]
pub fn recursive(&mut self, recursive: bool) -> &mut Self {
self.recursive = recursive;
self
}
/// Creates the specified directory with the options configured in this
/// builder.
///
/// It is considered an error if the directory already exists unless
/// recursive mode is enabled.
///
/// # Examples
///
/// ```no_run
/// use std::fs::{self, DirBuilder};
///
/// let path = "/tmp/foo/bar/baz";
/// DirBuilder::new()
/// .recursive(true)
/// .create(path).unwrap();
///
/// assert!(fs::metadata(path).unwrap().is_dir());
/// ```
#[stable(feature = "dir_builder", since = "1.6.0")]
pub fn create<P: AsRef<Path>>(&self, path: P) -> io::Result<()> {
self._create(path.as_ref())
}
fn _create(&self, path: &Path) -> io::Result<()> {
if self.recursive { self.create_dir_all(path) } else { self.inner.mkdir(path) }
}
fn create_dir_all(&self, path: &Path) -> io::Result<()> {
if path == Path::new("") {
return Ok(());
}
match self.inner.mkdir(path) {
Ok(()) => return Ok(()),
Err(ref e) if e.kind() == io::ErrorKind::NotFound => {}
Err(_) if path.is_dir() => return Ok(()),
Err(e) => return Err(e),
}
match path.parent() {
Some(p) => self.create_dir_all(p)?,
None => {
return Err(io::const_io_error!(
io::ErrorKind::Uncategorized,
"failed to create whole tree",
));
}
}
match self.inner.mkdir(path) {
Ok(()) => Ok(()),
Err(_) if path.is_dir() => Ok(()),
Err(e) => Err(e),
}
}
}
impl AsInnerMut<fs_imp::DirBuilder> for DirBuilder {
#[inline]
fn as_inner_mut(&mut self) -> &mut fs_imp::DirBuilder {
&mut self.inner
}
}
/// Returns `Ok(true)` if the path points at an existing entity.
///
/// This function will traverse symbolic links to query information about the
/// destination file. In case of broken symbolic links this will return `Ok(false)`.
///
/// As opposed to the [`Path::exists`] method, this will only return `Ok(true)` or `Ok(false)`
/// if the path was _verified_ to exist or not exist. If its existence can neither be confirmed
/// nor denied, an `Err(_)` will be propagated instead. This can be the case if e.g. listing
/// permission is denied on one of the parent directories.
///
/// Note that while this avoids some pitfalls of the `exists()` method, it still can not
/// prevent time-of-check to time-of-use (TOCTOU) bugs. You should only use it in scenarios
/// where those bugs are not an issue.
///
/// # Examples
///
/// ```no_run
/// use std::fs;
///
/// assert!(!fs::exists("does_not_exist.txt").expect("Can't check existence of file does_not_exist.txt"));
/// assert!(fs::exists("/root/secret_file.txt").is_err());
/// ```
///
/// [`Path::exists`]: crate::path::Path::exists
#[stable(feature = "fs_try_exists", since = "1.81.0")]
#[inline]
pub fn exists<P: AsRef<Path>>(path: P) -> io::Result<bool> {
fs_imp::exists(path.as_ref())
}