Enum clio::Input

pub enum Input {
    Stdin(Stdin),
    Pipe(OsString, File),
    File(OsString, File),
}

An enum that represents a command line input stream, either std in or a file

It is designed to be used with the clap crate when taking a file name as an argument to CLI app

use clap::Parser;
use clio::Input;

#[derive(Parser)]
struct Opt {
    /// path to file, use '-' for stdin
    #[clap(parse(try_from_os_str = TryFrom::try_from))]
    input_file: Input,
}

Variants

Stdin(Stdin)

Pipe(OsString, File)

File(OsString, File)

Implementations

impl Input

pub fn new<S: AsRef<OsStr>>(path: S) -> Result<Self>

Contructs a new input either by opening the file or for ‘-’ returning stdin

pub fn try_from_os_str(path: &OsStr) -> Result<Self, OsString>

Contructs a new input either by opening the file or for ‘-’ returning stdin

The error is converted to a OsString so that stuctopt can show it to the user.

It is recomended that you use TryFrom::try_from and clap 3.0 instead.

pub fn len(&self) -> Option<u64>

If input is a file, returns the size of the file, in bytes otherwise if input is stdin returns none.

Examples

let file = clio::Input::new("foo.txt").unwrap();

assert_eq!(Some(3), file.len());

pub fn is_empty(&self) -> Option<bool>

Returns a boolean saying if the file is empty, if using stdin returns None

Examples

let file = clio::Input::new("foo.txt").unwrap();

assert_eq!(Some(true), file.is_empty());

pub fn lock<'a>(&'a mut self) -> Box<dyn BufRead + 'a>

If the input is std in locks it, otherwise wraps the file in a buffered reader. This is useful to get the line iterator of the BufRead.

Examples

use std::io::BufRead;
let mut file = clio::Input::new("-")?;

for line in file.lock().lines() {
  println!("line is: {}", line?);
}

pub fn path(&self) -> &OsStr

Returns the path/url used to create the input

Trait Implementations

impl Debug for Input

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

Formats the value using the given formatter.

impl Display for Input

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

Formats the value using the given formatter.

impl Read for Input

fn read(&mut self, buf: &mut [u8]) -> IoResult<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬 This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8, Global>) -> Result<usize, Error>

Read all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Read all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Read the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>

🔬 This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact(&mut self, buf: &mut ReadBuf<'_>) -> Result<(), Error>

🔬 This is a nightly-only experimental API. (read_buf)

Read the exact number of bytes required to fill buf.

fn by_ref(&mut self) -> &mut Self

Creates a “by reference” adaptor for this instance of Read.

fn bytes(self) -> Bytes<Self>

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R> where
    R: Read, 

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

Creates an adapter which will read at most limit bytes from it.

impl Seek for Input

fn seek(&mut self, pos: SeekFrom) -> IoResult<u64>

Seek to an offset, in bytes, in a stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬 This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

impl TryFrom<&'_ OsStr> for Input

type Error = Error

The type returned in the event of a conversion error.

fn try_from(file_name: &OsStr) -> Result<Self>

Performs the conversion.