Struct std::fs::Metadata

1.0.0 · source ·
pub struct Metadata(/* private fields */);
Expand description

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§

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impl Metadata

1.1.0 · source

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(())
}
Run
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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(())
}
Run
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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(())
}
Run

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(())
}
Run
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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(())
}
Run
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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(())
}
Run
1.10.0 · source

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

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(())
}
Run
1.10.0 · source

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

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(())
}
Run
1.10.0 · source

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

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(())
}
Run

Trait Implementations§

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impl Clone for Metadata

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fn clone(&self) -> Metadata

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
1.16.0 · source§

impl Debug for Metadata

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

Formats the value using the given formatter. Read more
1.1.0 · source§

impl MetadataExt for Metadata

Available on Windows only.
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fn file_attributes(&self) -> u32

Returns the value of the dwFileAttributes field of this metadata. Read more
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fn creation_time(&self) -> u64

Returns the value of the ftCreationTime field of this metadata. Read more
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fn last_access_time(&self) -> u64

Returns the value of the ftLastAccessTime field of this metadata. Read more
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fn last_write_time(&self) -> u64

Returns the value of the ftLastWriteTime field of this metadata. Read more
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fn file_size(&self) -> u64

Returns the value of the nFileSize{High,Low} fields of this metadata. Read more
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fn volume_serial_number(&self) -> Option<u32>

🔬This is a nightly-only experimental API. (windows_by_handle #63010)
Returns the value of the dwVolumeSerialNumber field of this metadata. Read more
🔬This is a nightly-only experimental API. (windows_by_handle #63010)
Returns the value of the nNumberOfLinks field of this metadata. Read more
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fn file_index(&self) -> Option<u64>

🔬This is a nightly-only experimental API. (windows_by_handle #63010)
Returns the value of the nFileIndex{Low,High} fields of this metadata. Read more
1.1.0 · source§

impl MetadataExt for Metadata

Available on Linux only.
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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. Read more
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fn st_dev(&self) -> u64

Returns the device ID on which this file resides. Read more
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fn st_ino(&self) -> u64

Returns the inode number. Read more
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fn st_mode(&self) -> u32

Returns the file type and mode. Read more
Returns the number of hard links to file. Read more
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fn st_uid(&self) -> u32

Returns the user ID of the file owner. Read more
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fn st_gid(&self) -> u32

Returns the group ID of the file owner. Read more
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fn st_rdev(&self) -> u64

Returns the device ID that this file represents. Only relevant for special file. Read more
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fn st_size(&self) -> u64

Returns the size of the file (if it is a regular file or a symbolic link) in bytes. Read more
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fn st_atime(&self) -> i64

Returns the last access time of the file, in seconds since Unix Epoch. Read more
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fn st_atime_nsec(&self) -> i64

Returns the last access time of the file, in nanoseconds since st_atime. Read more
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fn st_mtime(&self) -> i64

Returns the last modification time of the file, in seconds since Unix Epoch. Read more
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fn st_mtime_nsec(&self) -> i64

Returns the last modification time of the file, in nanoseconds since st_mtime. Read more
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fn st_ctime(&self) -> i64

Returns the last status change time of the file, in seconds since Unix Epoch. Read more
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fn st_ctime_nsec(&self) -> i64

Returns the last status change time of the file, in nanoseconds since st_ctime. Read more
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fn st_blksize(&self) -> u64

Returns the “preferred” block size for efficient filesystem I/O. Read more
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fn st_blocks(&self) -> u64

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

impl MetadataExt for Metadata

Available on Unix only.
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fn dev(&self) -> u64

Returns the ID of the device containing the file. Read more
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fn ino(&self) -> u64

Returns the inode number. Read more
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fn mode(&self) -> u32

Returns the rights applied to this file. Read more
Returns the number of hard links pointing to this file. Read more
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fn uid(&self) -> u32

Returns the user ID of the owner of this file. Read more
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fn gid(&self) -> u32

Returns the group ID of the owner of this file. Read more
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fn rdev(&self) -> u64

Returns the device ID of this file (if it is a special one). Read more
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fn size(&self) -> u64

Returns the total size of this file in bytes. Read more
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fn atime(&self) -> i64

Returns the last access time of the file, in seconds since Unix Epoch. Read more
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fn atime_nsec(&self) -> i64

Returns the last access time of the file, in nanoseconds since atime. Read more
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fn mtime(&self) -> i64

Returns the last modification time of the file, in seconds since Unix Epoch. Read more
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fn mtime_nsec(&self) -> i64

Returns the last modification time of the file, in nanoseconds since mtime. Read more
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fn ctime(&self) -> i64

Returns the last status change time of the file, in seconds since Unix Epoch. Read more
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fn ctime_nsec(&self) -> i64

Returns the last status change time of the file, in nanoseconds since ctime. Read more
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fn blksize(&self) -> u64

Returns the block size for filesystem I/O. Read more
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fn blocks(&self) -> u64

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

Available on WASI only.
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fn dev(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_dev field of the internal filestat_t
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fn ino(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_ino field of the internal filestat_t
🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_nlink field of the internal filestat_t
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fn size(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_size field of the internal filestat_t
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fn atim(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_atim field of the internal filestat_t
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fn mtim(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_mtim field of the internal filestat_t
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fn ctim(&self) -> u64

🔬This is a nightly-only experimental API. (wasi_ext #71213)
Returns the st_ctim field of the internal filestat_t

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type Owned = T

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type Error = <U as TryFrom<T>>::Error

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