Struct Input

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

Represents an input source, which can be either standard input or a file.

Examples

use std::io::{self, BufRead as _};

use clap::Parser as _;
use clap_file::Input;

#[derive(Debug, clap::Parser)]
struct Args {
    /// Input file. If not provided, reads from standard input.
    input: Input,
}

fn main() -> io::Result<()> {
    let args = Args::parse();
    let input = args.input.lock();
    for line in input.lines() {
        let line = line?;
        println!("{line}");
    }
    Ok(())
}

Implementations

impl Input

pub fn stdin() -> Self

Creates a new Input instance that reads from standard input.

pub fn open(path: PathBuf) -> Result<Self>

Opens a file at the given path and creates a new Input instance that reads from it.

pub fn is_stdin(&self) -> bool

Returns true if this Input reads from standard input.

pub fn is_file(&self) -> bool

Returns true if this Input reads from a file.

pub fn path(&self) -> Option<&Path>

Returns the path of the file this Input reads from.

Returns None if this Input reads from standard input.

pub fn lock(&self) -> LockedInput<'_>

Locks the input source and returns a LockedInput instance.

This lock is released when the returned LockedInput instance is dropped. The returned LockedInput instance implements Read and BufRead traits.

Trait Implementations

impl Clone for Input

fn clone(&self) -> Input

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Input

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

Formats the value using the given formatter.

impl FromStr for Input

type Err = Error

The associated error which can be returned from parsing.

fn from_str(s: &str) -> Result<Self, Self::Err>

Parses a string s to return a value of this type.

impl Read for Input

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

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

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

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

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

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

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

Reads the exact number of bytes required to fill buf.

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_buf(&mut self, buf: BorrowedCursor<'_>) -> 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, cursor: BorrowedCursor<'_>) -> Result<(), Error>

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

Reads the exact number of bytes required to fill cursor.

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

where Self: Sized,

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

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

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

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

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

where Self: Sized,

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