Struct snarkvm_wasm::fs::Metadata

1.0.0 · source ·

pub struct Metadata(_);

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

source

impl Metadata

1.1.0 · source

pub fn file_type(&self) -> FileType

Returns the file type for this metadata.

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.

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(())
}

1.58.0 · source

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(())
}

source

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(())
}

source

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(())
}

1.10.0 · source

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(())
}

1.10.0 · source

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(())
}

1.10.0 · source

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(())
}