Struct async_std::fs::Metadata

pub struct Metadata(_);

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 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 may 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 may 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 may 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

pub fn clone(&self) -> Metadata

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Metadata

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

Formats the value using the given formatter.

impl MetadataExt for Metadata

pub fn dev(&self) -> u64

Returns the ID of the device containing the file.

pub fn ino(&self) -> u64

Returns the inode number.

pub fn mode(&self) -> u32

Returns the rights applied to this file.

pub fn nlink(&self) -> u64

Returns the number of hard links pointing to this file.

pub fn uid(&self) -> u32

Returns the user ID of the owner of this file.

pub fn gid(&self) -> u32

Returns the group ID of the owner of this file.

pub fn rdev(&self) -> u64

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

pub fn size(&self) -> u64

Returns the total size of this file in bytes.

pub fn atime(&self) -> i64

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

pub fn atime_nsec(&self) -> i64

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

pub fn mtime(&self) -> i64

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

pub fn mtime_nsec(&self) -> i64

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

pub fn ctime(&self) -> i64

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

pub fn ctime_nsec(&self) -> i64

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

pub fn blksize(&self) -> u64

Returns the block size for filesystem I/O.

pub fn blocks(&self) -> u64

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

impl MetadataExt for Metadata

pub 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.

pub fn st_dev(&self) -> u64

Returns the device ID on which this file resides.

pub fn st_ino(&self) -> u64

Returns the inode number.

pub fn st_mode(&self) -> u32

Returns the file type and mode.

pub fn st_nlink(&self) -> u64

Returns the number of hard links to file.

pub fn st_uid(&self) -> u32

Returns the user ID of the file owner.

pub fn st_gid(&self) -> u32

Returns the group ID of the file owner.

pub fn st_rdev(&self) -> u64

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

pub fn st_size(&self) -> u64

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

pub fn st_atime(&self) -> i64

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

pub fn st_atime_nsec(&self) -> i64

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

pub fn st_mtime(&self) -> i64

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

pub fn st_mtime_nsec(&self) -> i64

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

pub fn st_ctime(&self) -> i64

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

pub fn st_ctime_nsec(&self) -> i64

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

pub fn st_blksize(&self) -> u64

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

pub fn st_blocks(&self) -> u64

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