Struct Metadata

pub struct Metadata(/* private fields */);

Available on crate feature std only.

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.

Implementations

impl Metadata

pub fn file_type(&self) -> FileType

Returns the file type for this metadata.

Examples

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

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

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

pub fn is_dir(&self) -> bool

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

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

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

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

pub fn is_file(&self) -> bool

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

use std::fs;

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

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

pub fn is_symlink(&self) -> bool

Returns true if this metadata is for a symbolic link.

Examples

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(())
}

pub fn len(&self) -> u64

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

Examples

use std::fs;

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

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

pub fn permissions(&self) -> Permissions

Returns the permissions of the file this metadata is for.

Examples

use std::fs;

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

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

pub fn modified(&self) -> Result<SystemTime, Error>

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

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(())
}

pub fn accessed(&self) -> Result<SystemTime, Error>

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

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(())
}

pub fn created(&self) -> Result<SystemTime, Error>

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

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(())
}

Trait Implementations

impl Clone for Metadata

fn clone(&self) -> Metadata

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Metadata

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl MetadataExt for Metadata

fn dev(&self) -> u64

Returns the ID of the device containing the file.

fn ino(&self) -> u64

Returns the inode number.

fn mode(&self) -> u32

Returns the rights applied to this file.

fn nlink(&self) -> u64

Returns the number of hard links pointing to this file.

fn uid(&self) -> u32

Returns the user ID of the owner of this file.

fn gid(&self) -> u32

Returns the group ID of the owner of this file.

fn rdev(&self) -> u64

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

fn size(&self) -> u64

Returns the total size of this file in bytes.

fn atime(&self) -> i64

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

fn atime_nsec(&self) -> i64

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

fn mtime(&self) -> i64

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

fn mtime_nsec(&self) -> i64

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

fn ctime(&self) -> i64

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

fn ctime_nsec(&self) -> i64

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

fn blksize(&self) -> u64

Returns the block size for filesystem I/O.

fn blocks(&self) -> u64

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

impl MetadataExt for Metadata

fn as_raw_stat(&self) -> &stat

👎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.

fn st_dev(&self) -> u64

Returns the device ID on which this file resides.

fn st_ino(&self) -> u64

Returns the inode number.

fn st_mode(&self) -> u32

Returns the file type and mode.

fn st_nlink(&self) -> u64

Returns the number of hard links to file.

fn st_uid(&self) -> u32

Returns the user ID of the file owner.

fn st_gid(&self) -> u32

Returns the group ID of the file owner.

fn st_rdev(&self) -> u64

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

fn st_size(&self) -> u64

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

fn st_atime(&self) -> i64

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

fn st_atime_nsec(&self) -> i64

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

fn st_mtime(&self) -> i64

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

fn st_mtime_nsec(&self) -> i64

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

fn st_ctime(&self) -> i64

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

fn st_ctime_nsec(&self) -> i64

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

fn st_blksize(&self) -> u64

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

fn st_blocks(&self) -> u64

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