fs.rs.html -- source
Description: Source to the Rust file `src/libstd/sys/unix/ext/fs.rs`.
Keywords: rust, rustlang, rust-lang

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    // Copyright 2015 The Rust Project Developers. See the COPYRIGHT
    // file at the top-level directory of this distribution and at
    // http://rust-lang.org/COPYRIGHT.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    //! Unix-specific extensions to primitives in the `std::fs` module.

    #![stable(feature = "rust1", since = "1.0.0")]

    use fs::{self, Permissions, OpenOptions};
    use io;
    use libc;
    use path::Path;
    use sys;
    use sys_common::{FromInner, AsInner, AsInnerMut};
    use sys::platform::fs::MetadataExt as UnixMetadataExt;

    /// Unix-specific extensions to `File`
    #[stable(feature = "file_offset", since = "1.15.0")]
    pub trait FileExt {
        /// Reads a number of bytes starting from a given offset.
        ///
        /// 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 file cursor is not affected by this function.
        ///
        /// Note that similar to `File::read`, it is not an error to return with a
        /// short read.
        #[stable(feature = "file_offset", since = "1.15.0")]
        fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize>;

        /// Writes a number of bytes starting from a given offset.
        ///
        /// 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 file cursor is not affected by this function.
        ///
        /// When writing beyond the end of the file, the file is appropiately
        /// extended and the intermediate bytes are initialized with the value 0.
        ///
        /// Note that similar to `File::write`, it is not an error to return a
        /// short write.
        #[stable(feature = "file_offset", since = "1.15.0")]
        fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize>;
    }

    #[stable(feature = "file_offset", since = "1.15.0")]
    impl FileExt for fs::File {
        fn read_at(&self, buf: &mut [u8], offset: u64) -> io::Result<usize> {
            self.as_inner().read_at(buf, offset)
        }
        fn write_at(&self, buf: &[u8], offset: u64) -> io::Result<usize> {
            self.as_inner().write_at(buf, offset)
        }
    }

    /// Unix-specific extensions to `Permissions`
    #[stable(feature = "fs_ext", since = "1.1.0")]
    pub trait PermissionsExt {
        /// Returns the underlying raw `mode_t` bits that are the standard Unix
        /// permissions for this file.
        ///
        /// # Examples
        ///
        /// ```rust,ignore
        /// use std::fs::File;
        /// use std::os::unix::fs::PermissionsExt;
        ///
        /// let f = try!(File::create("foo.txt"));
        /// let metadata = try!(f.metadata());
        /// let permissions = metadata.permissions();
        ///
        /// println!("permissions: {}", permissions.mode());
        /// ```
        #[stable(feature = "fs_ext", since = "1.1.0")]
        fn mode(&self) -> u32;

        /// Sets the underlying raw bits for this set of permissions.
        ///
        /// # Examples
        ///
        /// ```rust,ignore
        /// use std::fs::File;
        /// use std::os::unix::fs::PermissionsExt;
        ///
        /// let f = try!(File::create("foo.txt"));
        /// let metadata = try!(f.metadata());
        /// let mut permissions = metadata.permissions();
        ///
        /// permissions.set_mode(0o644); // Read/write for owner and read for others.
        /// assert_eq!(permissions.mode(), 0o644);
        /// ```
        #[stable(feature = "fs_ext", since = "1.1.0")]
        fn set_mode(&mut self, mode: u32);

        /// Creates a new instance of `Permissions` from the given set of Unix
        /// permission bits.
        ///
        /// # Examples
        ///
        /// ```rust,ignore
        /// use std::fs::Permissions;
        /// use std::os::unix::fs::PermissionsExt;
        ///
        /// // Read/write for owner and read for others.
        /// let permissions = Permissions::from_mode(0o644);
        /// assert_eq!(permissions.mode(), 0o644);
        /// ```
        #[stable(feature = "fs_ext", since = "1.1.0")]
        fn from_mode(mode: u32) -> Self;
    }

    #[stable(feature = "fs_ext", since = "1.1.0")]
    impl PermissionsExt for Permissions {
        fn mode(&self) -> u32 {
            self.as_inner().mode()
        }

        fn set_mode(&mut self, mode: u32) {
            *self = Permissions::from_inner(FromInner::from_inner(mode));
        }

        fn from_mode(mode: u32) -> Permissions {
            Permissions::from_inner(FromInner::from_inner(mode))
        }
    }

    /// Unix-specific extensions to `OpenOptions`
    #[stable(feature = "fs_ext", since = "1.1.0")]
    pub trait OpenOptionsExt {
        /// Sets the mode bits that a new file will be created with.
        ///
        /// If a new file is created as part of a `File::open_opts` call then this
        /// specified `mode` will be used as the permission bits for the new file.
        /// If no `mode` is set, the default of `0o666` will be used.
        /// The operating system masks out bits with the systems `umask`, to produce
        /// the final permissions.
        ///
        /// # Examples
        ///
        /// ```rust,ignore
        /// extern crate libc;
        /// use std::fs::OpenOptions;
        /// use std::os::unix::fs::OpenOptionsExt;
        ///
        /// let mut options = OpenOptions::new();
        /// options.mode(0o644); // Give read/write for owner and read for others.
        /// let file = options.open("foo.txt");
        /// ```
        #[stable(feature = "fs_ext", since = "1.1.0")]
        fn mode(&mut self, mode: u32) -> &mut Self;

        /// Pass custom flags to the `flags` agument of `open`.
        ///
        /// The bits that define the access mode are masked out with `O_ACCMODE`, to
        /// ensure they do not interfere with the access mode set by Rusts options.
        ///
        /// Custom flags can only set flags, not remove flags set by Rusts options.
        /// This options overwrites any previously set custom flags.
        ///
        /// # Examples
        ///
        /// ```rust,ignore
        /// extern crate libc;
        /// use std::fs::OpenOptions;
        /// use std::os::unix::fs::OpenOptionsExt;
        ///
        /// let mut options = OpenOptions::new();
        /// options.write(true);
        /// if cfg!(unix) {
        ///     options.custom_flags(libc::O_NOFOLLOW);
        /// }
        /// let file = options.open("foo.txt");
        /// ```
        #[stable(feature = "open_options_ext", since = "1.10.0")]
        fn custom_flags(&mut self, flags: i32) -> &mut Self;
    }

    #[stable(feature = "fs_ext", since = "1.1.0")]
    impl OpenOptionsExt for OpenOptions {
        fn mode(&mut self, mode: u32) -> &mut OpenOptions {
            self.as_inner_mut().mode(mode); self
        }

        fn custom_flags(&mut self, flags: i32) -> &mut OpenOptions {
            self.as_inner_mut().custom_flags(flags); self
        }
    }

    // Hm, why are there casts here to the returned type, shouldn't the types always
    // be the same? Right you are! Turns out, however, on android at least the types
    // in the raw `stat` structure are not the same as the types being returned. Who
    // knew!
    //
    // As a result to make sure this compiles for all platforms we do the manual
    // casts and rely on manual lowering to `stat` if the raw type is desired.
    #[stable(feature = "metadata_ext", since = "1.1.0")]
    pub trait MetadataExt {
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn dev(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn ino(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn mode(&self) -> u32;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn nlink(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn uid(&self) -> u32;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn gid(&self) -> u32;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn rdev(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn size(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn atime(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn atime_nsec(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn mtime(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn mtime_nsec(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn ctime(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn ctime_nsec(&self) -> i64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn blksize(&self) -> u64;
        #[stable(feature = "metadata_ext", since = "1.1.0")]
        fn blocks(&self) -> u64;
    }

    #[stable(feature = "metadata_ext", since = "1.1.0")]
    impl MetadataExt for fs::Metadata {
        fn dev(&self) -> u64 { self.st_dev() }
        fn ino(&self) -> u64 { self.st_ino() }
        fn mode(&self) -> u32 { self.st_mode() }
        fn nlink(&self) -> u64 { self.st_nlink() }
        fn uid(&self) -> u32 { self.st_uid() }
        fn gid(&self) -> u32 { self.st_gid() }
        fn rdev(&self) -> u64 { self.st_rdev() }
        fn size(&self) -> u64 { self.st_size() }
        fn atime(&self) -> i64 { self.st_atime() }
        fn atime_nsec(&self) -> i64 { self.st_atime_nsec() }
        fn mtime(&self) -> i64 { self.st_mtime() }
        fn mtime_nsec(&self) -> i64 { self.st_mtime_nsec() }
        fn ctime(&self) -> i64 { self.st_ctime() }
        fn ctime_nsec(&self) -> i64 { self.st_ctime_nsec() }
        fn blksize(&self) -> u64 { self.st_blksize() }
        fn blocks(&self) -> u64 { self.st_blocks() }
    }

    /// Add special unix types (block/char device, fifo and socket)
    #[stable(feature = "file_type_ext", since = "1.5.0")]
    pub trait FileTypeExt {
        /// Returns whether this file type is a block device.
        #[stable(feature = "file_type_ext", since = "1.5.0")]
        fn is_block_device(&self) -> bool;
        /// Returns whether this file type is a char device.
        #[stable(feature = "file_type_ext", since = "1.5.0")]
        fn is_char_device(&self) -> bool;
        /// Returns whether this file type is a fifo.
        #[stable(feature = "file_type_ext", since = "1.5.0")]
        fn is_fifo(&self) -> bool;
        /// Returns whether this file type is a socket.
        #[stable(feature = "file_type_ext", since = "1.5.0")]
        fn is_socket(&self) -> bool;
    }

    #[stable(feature = "file_type_ext", since = "1.5.0")]
    impl FileTypeExt for fs::FileType {
        fn is_block_device(&self) -> bool { self.as_inner().is(libc::S_IFBLK) }
        fn is_char_device(&self) -> bool { self.as_inner().is(libc::S_IFCHR) }
        fn is_fifo(&self) -> bool { self.as_inner().is(libc::S_IFIFO) }
        fn is_socket(&self) -> bool { self.as_inner().is(libc::S_IFSOCK) }
    }

    /// Unix-specific extension methods for `fs::DirEntry`
    #[stable(feature = "dir_entry_ext", since = "1.1.0")]
    pub trait DirEntryExt {
        /// Returns the underlying `d_ino` field in the contained `dirent`
        /// structure.
        ///
        /// # Examples
        ///
        /// ```
        /// use std::fs;
        /// use std::os::unix::fs::DirEntryExt;
        ///
        /// 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(), entry.ino());
        ///         }
        ///     }
        /// }
        /// ```
        #[stable(feature = "dir_entry_ext", since = "1.1.0")]
        fn ino(&self) -> u64;
    }

    #[stable(feature = "dir_entry_ext", since = "1.1.0")]
    impl DirEntryExt for fs::DirEntry {
        fn ino(&self) -> u64 { self.as_inner().ino() }
    }

    /// Creates a new symbolic link on the filesystem.
    ///
    /// The `dst` path will be a symbolic link pointing to the `src` path.
    ///
    /// # Note
    ///
    /// On Windows, you must specify whether a symbolic link points to a file
    /// or directory.  Use `os::windows::fs::symlink_file` to create a
    /// symbolic link to a file, or `os::windows::fs::symlink_dir` to create a
    /// symbolic link to a directory.  Additionally, the process must have
    /// `SeCreateSymbolicLinkPrivilege` in order to be able to create a
    /// symbolic link.
    ///
    /// # Examples
    ///
    /// ```
    /// use std::os::unix::fs;
    ///
    /// # fn foo() -> std::io::Result<()> {
    /// try!(fs::symlink("a.txt", "b.txt"));
    /// # Ok(())
    /// # }
    /// ```
    #[stable(feature = "symlink", since = "1.1.0")]
    pub fn symlink<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> io::Result<()>
    {
        sys::fs::symlink(src.as_ref(), dst.as_ref())
    }

    #[stable(feature = "dir_builder", since = "1.6.0")]
    /// An extension trait for `fs::DirBuilder` for unix-specific options.
    pub trait DirBuilderExt {
        /// Sets the mode to create new directories with. This option defaults to
        /// 0o777.
        ///
        /// # Examples
        ///
        /// ```ignore
        /// use std::fs::DirBuilder;
        /// use std::os::unix::fs::DirBuilderExt;
        ///
        /// let mut builder = DirBuilder::new();
        /// builder.mode(0o755);
        /// ```
        #[stable(feature = "dir_builder", since = "1.6.0")]
        fn mode(&mut self, mode: u32) -> &mut Self;
    }

    #[stable(feature = "dir_builder", since = "1.6.0")]
    impl DirBuilderExt for fs::DirBuilder {
        fn mode(&mut self, mode: u32) -> &mut fs::DirBuilder {
            self.as_inner_mut().set_mode(mode);
            self
        }
    }

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