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//! Windows-specific extensions to primitives in the [`std::fs`] module.
//!
//! [`std::fs`]: crate::fs
#![stable(feature = "rust1", since = "1.0.0")]
use crate::fs::{self, Metadata, OpenOptions};
use crate::path::Path;
use crate::sealed::Sealed;
use crate::sys_common::{AsInner, AsInnerMut, IntoInner};
use crate::time::SystemTime;
use crate::{io, sys};
/// Windows-specific extensions to [`fs::File`].
#[stable(feature = "file_offset", since = "1.15.0")]
pub trait FileExt {
/// Seeks to a given position and reads a number of bytes.
///
/// Returns the number of bytes read.
///
/// The offset is relative to the start of the file and thus independent
/// from the current cursor. The current cursor **is** affected by this
/// function, it is set to the end of the read.
///
/// Reading beyond the end of the file will always return with a length of
/// 0\.
///
/// Note that similar to `File::read`, it is not an error to return with a
/// short read. When returning from such a short read, the file pointer is
/// still updated.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs::File;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let mut file = File::open("foo.txt")?;
/// let mut buffer = [0; 10];
///
/// // Read 10 bytes, starting 72 bytes from the
/// // start of the file.
/// file.seek_read(&mut buffer[..], 72)?;
/// Ok(())
/// }
/// ```
#[stable(feature = "file_offset", since = "1.15.0")]
fn seek_read(&self, buf: &mut [u8], offset: u64) -> io::Result<usize>;
/// Seeks to a given position and writes a number of bytes.
///
/// Returns the number of bytes written.
///
/// The offset is relative to the start of the file and thus independent
/// from the current cursor. The current cursor **is** affected by this
/// function, it is set to the end of the write.
///
/// When writing beyond the end of the file, the file is appropriately
/// extended and the intermediate bytes are set to zero.
///
/// Note that similar to `File::write`, it is not an error to return a
/// short write. When returning from such a short write, the file pointer
/// is still updated.
///
/// # Examples
///
/// ```no_run
/// use std::fs::File;
/// use std::os::windows::prelude::*;
///
/// fn main() -> std::io::Result<()> {
/// let mut buffer = File::create("foo.txt")?;
///
/// // Write a byte string starting 72 bytes from
/// // the start of the file.
/// buffer.seek_write(b"some bytes", 72)?;
/// Ok(())
/// }
/// ```
#[stable(feature = "file_offset", since = "1.15.0")]
fn seek_write(&self, buf: &[u8], offset: u64) -> io::Result<usize>;
}
#[stable(feature = "file_offset", since = "1.15.0")]
impl FileExt for fs::File {
fn seek_read(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
self.as_inner().read_at(buf, offset)
}
fn seek_write(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
self.as_inner().write_at(buf, offset)
}
}
/// Windows-specific extensions to [`fs::OpenOptions`].
#[stable(feature = "open_options_ext", since = "1.10.0")]
pub trait OpenOptionsExt {
/// Overrides the `dwDesiredAccess` argument to the call to [`CreateFile`]
/// with the specified value.
///
/// This will override the `read`, `write`, and `append` flags on the
/// `OpenOptions` structure. This method provides fine-grained control over
/// the permissions to read, write and append data, attributes (like hidden
/// and system), and extended attributes.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
/// use std::os::windows::prelude::*;
///
/// // Open without read and write permission, for example if you only need
/// // to call `stat` on the file
/// let file = OpenOptions::new().access_mode(0).open("foo.txt");
/// ```
///
/// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
#[stable(feature = "open_options_ext", since = "1.10.0")]
fn access_mode(&mut self, access: u32) -> &mut Self;
/// Overrides the `dwShareMode` argument to the call to [`CreateFile`] with
/// the specified value.
///
/// By default `share_mode` is set to
/// `FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE`. This allows
/// other processes to read, write, and delete/rename the same file
/// while it is open. Removing any of the flags will prevent other
/// processes from performing the corresponding operation until the file
/// handle is closed.
///
/// # Examples
///
/// ```no_run
/// use std::fs::OpenOptions;
/// use std::os::windows::prelude::*;
///
/// // Do not allow others to read or modify this file while we have it open
/// // for writing.
/// let file = OpenOptions::new()
/// .write(true)
/// .share_mode(0)
/// .open("foo.txt");
/// ```
///
/// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
#[stable(feature = "open_options_ext", since = "1.10.0")]
fn share_mode(&mut self, val: u32) -> &mut Self;
/// Sets extra flags for the `dwFileFlags` argument to the call to
/// [`CreateFile2`] to the specified value (or combines it with
/// `attributes` and `security_qos_flags` to set the `dwFlagsAndAttributes`
/// for [`CreateFile`]).
///
/// Custom flags can only set flags, not remove flags set by Rust's options.
/// This option overwrites any previously set custom flags.
///
/// # Examples
///
/// ```no_run
/// # #![allow(unexpected_cfgs)]
/// # #[cfg(for_demonstration_only)]
/// extern crate winapi;
/// # mod winapi { pub const FILE_FLAG_DELETE_ON_CLOSE: u32 = 0x04000000; }
///
/// use std::fs::OpenOptions;
/// use std::os::windows::prelude::*;
///
/// let file = OpenOptions::new()
/// .create(true)
/// .write(true)
/// .custom_flags(winapi::FILE_FLAG_DELETE_ON_CLOSE)
/// .open("foo.txt");
/// ```
///
/// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
/// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
#[stable(feature = "open_options_ext", since = "1.10.0")]
fn custom_flags(&mut self, flags: u32) -> &mut Self;
/// Sets the `dwFileAttributes` argument to the call to [`CreateFile2`] to
/// the specified value (or combines it with `custom_flags` and
/// `security_qos_flags` to set the `dwFlagsAndAttributes` for
/// [`CreateFile`]).
///
/// If a _new_ file is created because it does not yet exist and
/// `.create(true)` or `.create_new(true)` are specified, the new file is
/// given the attributes declared with `.attributes()`.
///
/// If an _existing_ file is opened with `.create(true).truncate(true)`, its
/// existing attributes are preserved and combined with the ones declared
/// with `.attributes()`.
///
/// In all other cases the attributes get ignored.
///
/// # Examples
///
/// ```no_run
/// # #![allow(unexpected_cfgs)]
/// # #[cfg(for_demonstration_only)]
/// extern crate winapi;
/// # mod winapi { pub const FILE_ATTRIBUTE_HIDDEN: u32 = 2; }
///
/// use std::fs::OpenOptions;
/// use std::os::windows::prelude::*;
///
/// let file = OpenOptions::new()
/// .write(true)
/// .create(true)
/// .attributes(winapi::FILE_ATTRIBUTE_HIDDEN)
/// .open("foo.txt");
/// ```
///
/// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
/// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
#[stable(feature = "open_options_ext", since = "1.10.0")]
fn attributes(&mut self, val: u32) -> &mut Self;
/// Sets the `dwSecurityQosFlags` argument to the call to [`CreateFile2`] to
/// the specified value (or combines it with `custom_flags` and `attributes`
/// to set the `dwFlagsAndAttributes` for [`CreateFile`]).
///
/// By default `security_qos_flags` is not set. It should be specified when
/// opening a named pipe, to control to which degree a server process can
/// act on behalf of a client process (security impersonation level).
///
/// When `security_qos_flags` is not set, a malicious program can gain the
/// elevated privileges of a privileged Rust process when it allows opening
/// user-specified paths, by tricking it into opening a named pipe. So
/// arguably `security_qos_flags` should also be set when opening arbitrary
/// paths. However the bits can then conflict with other flags, specifically
/// `FILE_FLAG_OPEN_NO_RECALL`.
///
/// For information about possible values, see [Impersonation Levels] on the
/// Windows Dev Center site. The `SECURITY_SQOS_PRESENT` flag is set
/// automatically when using this method.
/// # Examples
///
/// ```no_run
/// # #![allow(unexpected_cfgs)]
/// # #[cfg(for_demonstration_only)]
/// extern crate winapi;
/// # mod winapi { pub const SECURITY_IDENTIFICATION: u32 = 0; }
/// use std::fs::OpenOptions;
/// use std::os::windows::prelude::*;
///
/// let file = OpenOptions::new()
/// .write(true)
/// .create(true)
///
/// // Sets the flag value to `SecurityIdentification`.
/// .security_qos_flags(winapi::SECURITY_IDENTIFICATION)
///
/// .open(r"\\.\pipe\MyPipe");
/// ```
///
/// [`CreateFile`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfilea
/// [`CreateFile2`]: https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-createfile2
/// [Impersonation Levels]:
/// https://docs.microsoft.com/en-us/windows/win32/api/winnt/ne-winnt-security_impersonation_level
#[stable(feature = "open_options_ext", since = "1.10.0")]
fn security_qos_flags(&mut self, flags: u32) -> &mut Self;
}
#[stable(feature = "open_options_ext", since = "1.10.0")]
impl OpenOptionsExt for OpenOptions {
fn access_mode(&mut self, access: u32) -> &mut OpenOptions {
self.as_inner_mut().access_mode(access);
self
}
fn share_mode(&mut self, share: u32) -> &mut OpenOptions {
self.as_inner_mut().share_mode(share);
self
}
fn custom_flags(&mut self, flags: u32) -> &mut OpenOptions {
self.as_inner_mut().custom_flags(flags);
self
}
fn attributes(&mut self, attributes: u32) -> &mut OpenOptions {
self.as_inner_mut().attributes(attributes);
self
}
fn security_qos_flags(&mut self, flags: u32) -> &mut OpenOptions {
self.as_inner_mut().security_qos_flags(flags);
self
}
}
/// Windows-specific extensions to [`fs::Metadata`].
///
/// The data members that this trait exposes correspond to the members
/// of the [`BY_HANDLE_FILE_INFORMATION`] structure.
///
/// [`BY_HANDLE_FILE_INFORMATION`]:
/// https://docs.microsoft.com/en-us/windows/win32/api/fileapi/ns-fileapi-by_handle_file_information
#[stable(feature = "metadata_ext", since = "1.1.0")]
pub trait MetadataExt {
/// Returns the value of the `dwFileAttributes` field of this metadata.
///
/// This field contains the file system attribute information for a file
/// or directory. For possible values and their descriptions, see
/// [File Attribute Constants] in the Windows Dev Center.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
/// let attributes = metadata.file_attributes();
/// Ok(())
/// }
/// ```
///
/// [File Attribute Constants]:
/// https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants
#[stable(feature = "metadata_ext", since = "1.1.0")]
fn file_attributes(&self) -> u32;
/// Returns the value of the `ftCreationTime` field of this metadata.
///
/// The returned 64-bit value is equivalent to a [`FILETIME`] struct,
/// which represents the number of 100-nanosecond intervals since
/// January 1, 1601 (UTC). The struct is automatically
/// converted to a `u64` value, as that is the recommended way
/// to use it.
///
/// If the underlying filesystem does not support creation time, the
/// returned value is 0.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
/// let creation_time = metadata.creation_time();
/// Ok(())
/// }
/// ```
///
/// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
#[stable(feature = "metadata_ext", since = "1.1.0")]
fn creation_time(&self) -> u64;
/// Returns the value of the `ftLastAccessTime` field of this metadata.
///
/// The returned 64-bit value is equivalent to a [`FILETIME`] struct,
/// which represents the number of 100-nanosecond intervals since
/// January 1, 1601 (UTC). The struct is automatically
/// converted to a `u64` value, as that is the recommended way
/// to use it.
///
/// For a file, the value specifies the last time that a file was read
/// from or written to. For a directory, the value specifies when
/// the directory was created. For both files and directories, the
/// specified date is correct, but the time of day is always set to
/// midnight.
///
/// If the underlying filesystem does not support last access time, the
/// returned value is 0.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
/// let last_access_time = metadata.last_access_time();
/// Ok(())
/// }
/// ```
///
/// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
#[stable(feature = "metadata_ext", since = "1.1.0")]
fn last_access_time(&self) -> u64;
/// Returns the value of the `ftLastWriteTime` field of this metadata.
///
/// The returned 64-bit value is equivalent to a [`FILETIME`] struct,
/// which represents the number of 100-nanosecond intervals since
/// January 1, 1601 (UTC). The struct is automatically
/// converted to a `u64` value, as that is the recommended way
/// to use it.
///
/// For a file, the value specifies the last time that a file was written
/// to. For a directory, the structure specifies when the directory was
/// created.
///
/// If the underlying filesystem does not support the last write time,
/// the returned value is 0.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
/// let last_write_time = metadata.last_write_time();
/// Ok(())
/// }
/// ```
///
/// [`FILETIME`]: https://docs.microsoft.com/en-us/windows/win32/api/minwinbase/ns-minwinbase-filetime
#[stable(feature = "metadata_ext", since = "1.1.0")]
fn last_write_time(&self) -> u64;
/// Returns the value of the `nFileSize{High,Low}` fields of this
/// metadata.
///
/// The returned value does not have meaning for directories.
///
/// # Examples
///
/// ```no_run
/// use std::io;
/// use std::fs;
/// use std::os::windows::prelude::*;
///
/// fn main() -> io::Result<()> {
/// let metadata = fs::metadata("foo.txt")?;
/// let file_size = metadata.file_size();
/// Ok(())
/// }
/// ```
#[stable(feature = "metadata_ext", since = "1.1.0")]
fn file_size(&self) -> u64;
/// Returns the value of the `dwVolumeSerialNumber` field of this
/// metadata.
///
/// This will return `None` if the `Metadata` instance was created from a
/// call to `DirEntry::metadata`. If this `Metadata` was created by using
/// `fs::metadata` or `File::metadata`, then this will return `Some`.
#[unstable(feature = "windows_by_handle", issue = "63010")]
fn volume_serial_number(&self) -> Option<u32>;
/// Returns the value of the `nNumberOfLinks` field of this
/// metadata.
///
/// This will return `None` if the `Metadata` instance was created from a
/// call to `DirEntry::metadata`. If this `Metadata` was created by using
/// `fs::metadata` or `File::metadata`, then this will return `Some`.
#[unstable(feature = "windows_by_handle", issue = "63010")]
fn number_of_links(&self) -> Option<u32>;
/// Returns the value of the `nFileIndex{Low,High}` fields of this
/// metadata.
///
/// This will return `None` if the `Metadata` instance was created from a
/// call to `DirEntry::metadata`. If this `Metadata` was created by using
/// `fs::metadata` or `File::metadata`, then this will return `Some`.
#[unstable(feature = "windows_by_handle", issue = "63010")]
fn file_index(&self) -> Option<u64>;
/// Returns the change time, which is the last time file metadata was changed, such as
/// renames, attributes, etc
///
/// This will return `None` if the `Metadata` instance was not created using the `FILE_BASIC_INFO` type.
#[unstable(feature = "windows_change_time", issue = "121478")]
fn change_time(&self) -> Option<u64>;
}
#[stable(feature = "metadata_ext", since = "1.1.0")]
impl MetadataExt for Metadata {
fn file_attributes(&self) -> u32 {
self.as_inner().attrs()
}
fn creation_time(&self) -> u64 {
self.as_inner().created_u64()
}
fn last_access_time(&self) -> u64 {
self.as_inner().accessed_u64()
}
fn last_write_time(&self) -> u64 {
self.as_inner().modified_u64()
}
fn file_size(&self) -> u64 {
self.as_inner().size()
}
fn volume_serial_number(&self) -> Option<u32> {
self.as_inner().volume_serial_number()
}
fn number_of_links(&self) -> Option<u32> {
self.as_inner().number_of_links()
}
fn file_index(&self) -> Option<u64> {
self.as_inner().file_index()
}
fn change_time(&self) -> Option<u64> {
self.as_inner().changed_u64()
}
}
/// Windows-specific extensions to [`fs::FileType`].
///
/// On Windows, a symbolic link knows whether it is a file or directory.
#[stable(feature = "windows_file_type_ext", since = "1.64.0")]
pub trait FileTypeExt: Sealed {
/// Returns `true` if this file type is a symbolic link that is also a directory.
#[stable(feature = "windows_file_type_ext", since = "1.64.0")]
fn is_symlink_dir(&self) -> bool;
/// Returns `true` if this file type is a symbolic link that is also a file.
#[stable(feature = "windows_file_type_ext", since = "1.64.0")]
fn is_symlink_file(&self) -> bool;
}
#[stable(feature = "windows_file_type_ext", since = "1.64.0")]
impl Sealed for fs::FileType {}
#[stable(feature = "windows_file_type_ext", since = "1.64.0")]
impl FileTypeExt for fs::FileType {
fn is_symlink_dir(&self) -> bool {
self.as_inner().is_symlink_dir()
}
fn is_symlink_file(&self) -> bool {
self.as_inner().is_symlink_file()
}
}
/// Windows-specific extensions to [`fs::FileTimes`].
#[stable(feature = "file_set_times", since = "1.75.0")]
pub trait FileTimesExt: Sealed {
/// Set the creation time of a file.
#[stable(feature = "file_set_times", since = "1.75.0")]
fn set_created(self, t: SystemTime) -> Self;
}
#[stable(feature = "file_set_times", since = "1.75.0")]
impl FileTimesExt for fs::FileTimes {
fn set_created(mut self, t: SystemTime) -> Self {
self.as_inner_mut().set_created(t.into_inner());
self
}
}
/// Creates a new symlink to a non-directory file on the filesystem.
///
/// The `link` path will be a file symbolic link pointing to the `original`
/// path.
///
/// The `original` path should not be a directory or a symlink to a directory,
/// otherwise the symlink will be broken. Use [`symlink_dir`] for directories.
///
/// This function currently corresponds to [`CreateSymbolicLinkW`][CreateSymbolicLinkW].
/// Note that this [may change in the future][changes].
///
/// [CreateSymbolicLinkW]: https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createsymboliclinkw
/// [changes]: io#platform-specific-behavior
///
/// # Examples
///
/// ```no_run
/// use std::os::windows::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::symlink_file("a.txt", "b.txt")?;
/// Ok(())
/// }
/// ```
///
/// # Limitations
///
/// Windows treats symlink creation as a [privileged action][symlink-security],
/// therefore this function is likely to fail unless the user makes changes to
/// their system to permit symlink creation. Users can try enabling Developer
/// Mode, granting the `SeCreateSymbolicLinkPrivilege` privilege, or running
/// the process as an administrator.
///
/// [symlink-security]: https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/create-symbolic-links
#[stable(feature = "symlink", since = "1.1.0")]
pub fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
sys::fs::symlink_inner(original.as_ref(), link.as_ref(), false)
}
/// Creates a new symlink to a directory on the filesystem.
///
/// The `link` path will be a directory symbolic link pointing to the `original`
/// path.
///
/// The `original` path must be a directory or a symlink to a directory,
/// otherwise the symlink will be broken. Use [`symlink_file`] for other files.
///
/// This function currently corresponds to [`CreateSymbolicLinkW`][CreateSymbolicLinkW].
/// Note that this [may change in the future][changes].
///
/// [CreateSymbolicLinkW]: https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-createsymboliclinkw
/// [changes]: io#platform-specific-behavior
///
/// # Examples
///
/// ```no_run
/// use std::os::windows::fs;
///
/// fn main() -> std::io::Result<()> {
/// fs::symlink_dir("a", "b")?;
/// Ok(())
/// }
/// ```
///
/// # Limitations
///
/// Windows treats symlink creation as a [privileged action][symlink-security],
/// therefore this function is likely to fail unless the user makes changes to
/// their system to permit symlink creation. Users can try enabling Developer
/// Mode, granting the `SeCreateSymbolicLinkPrivilege` privilege, or running
/// the process as an administrator.
///
/// [symlink-security]: https://docs.microsoft.com/en-us/windows/security/threat-protection/security-policy-settings/create-symbolic-links
#[stable(feature = "symlink", since = "1.1.0")]
pub fn symlink_dir<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
sys::fs::symlink_inner(original.as_ref(), link.as_ref(), true)
}
/// Creates a junction point.
///
/// The `link` path will be a directory junction pointing to the original path.
/// If `link` is a relative path then it will be made absolute prior to creating the junction point.
/// The `original` path must be a directory or a link to a directory, otherwise the junction point will be broken.
///
/// If either path is not a local file path then this will fail.
#[unstable(feature = "junction_point", issue = "121709")]
pub fn junction_point<P: AsRef<Path>, Q: AsRef<Path>>(original: P, link: Q) -> io::Result<()> {
sys::fs::junction_point(original.as_ref(), link.as_ref())
}