Metadata in std::fs - Rust (original) (raw)

Expand description

Metadata information about a file.

This structure is returned from the metadata orsymlink_metadata function or method and represents known metadata about a file such as its permissions, size, modification times, etc.

Returns the file type for this metadata.

fn main() -> std::io::Result<()> {
    use std::fs;

    let metadata = fs::metadata("foo.txt")?;

    println!("{:?}", metadata.file_type());
    Ok(())
}

Run

Returns true if this metadata is for a directory. The result is mutually exclusive to the result ofMetadata::is_file, and will be false for symlink metadata obtained from symlink_metadata.

fn main() -> std::io::Result<()> {
    use std::fs;

    let metadata = fs::metadata("foo.txt")?;

    assert!(!metadata.is_dir());
    Ok(())
}

Run

Returns true if this metadata is for a regular file. The result is mutually exclusive to the result ofMetadata::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 orOpenOptions::open for more information.

use std::fs;

fn main() -> std::io::Result<()> {
    let metadata = fs::metadata("foo.txt")?;

    assert!(metadata.is_file());
    Ok(())
}

Run

Returns true if this metadata is for a symbolic link.

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(())
}

Run

Returns the size of the file, in bytes, this metadata is for.

use std::fs;

fn main() -> std::io::Result<()> {
    let metadata = fs::metadata("foo.txt")?;

    assert_eq!(0, metadata.len());
    Ok(())
}

Run

Returns the permissions of the file this metadata is for.

use std::fs;

fn main() -> std::io::Result<()> {
    let metadata = fs::metadata("foo.txt")?;

    assert!(!metadata.permissions().readonly());
    Ok(())
}

Run

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.

This field might not be available on all platforms, and will return anErr on platforms where it is not available.

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(())
}

Run

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.

This field might not be available on all platforms, and will return anErr on platforms where it is not available.

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(())
}

Run

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.

This field might not be available on all platforms, and will return anErr on platforms or filesystems where it is not available.

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(())
}

Run

Formats the value using the given formatter. Read more

Returns the ID of the device containing the file. Read more

Returns the rights applied to this file. Read more

Returns the number of hard links pointing to this file. Read more

Returns the user ID of the owner of this file. Read more

Returns the group ID of the owner of this file. Read more

Returns the device ID of this file (if it is a special one). Read more

Returns the total size of this file in bytes. Read more

Returns the last access time of the file, in seconds since Unix Epoch. Read more

Returns the last access time of the file, in nanoseconds since atime. Read more

Returns the last modification time of the file, in seconds since Unix Epoch. Read more

Returns the last modification time of the file, in nanoseconds since mtime. Read more

Returns the last status change time of the file, in seconds since Unix Epoch. Read more

Returns the last status change time of the file, in nanoseconds since ctime. Read more

Returns the block size for filesystem I/O. Read more

Returns the number of blocks allocated to the file, in 512-byte units. Read more

👎 Deprecated since 1.8.0:

other methods of this trait are now preferred

Gain a reference to the underlying stat structure which contains the raw information returned by the OS. Read more

Returns the device ID on which this file resides. Read more

Returns the file type and mode. Read more

Returns the number of hard links to file. Read more

Returns the user ID of the file owner. Read more

Returns the group ID of the file owner. Read more

Returns the device ID that this file represents. Only relevant for special file. Read more

Returns the size of the file (if it is a regular file or a symbolic link) in bytes. Read more

Returns the last access time of the file, in seconds since Unix Epoch. Read more

Returns the last access time of the file, in nanoseconds since st_atime. Read more

Returns the last modification time of the file, in seconds since Unix Epoch. Read more

Returns the last modification time of the file, in nanoseconds since st_mtime. Read more

Returns the last status change time of the file, in seconds since Unix Epoch. Read more

Returns the last status change time of the file, in nanoseconds since st_ctime. Read more

Returns the “preferred” block size for efficient filesystem I/O. Read more

Returns the number of blocks allocated to the file, 512-byte units. Read more