Struct AutoStream

pub struct AutoStream<S: RawStream> { /* private fields */ }

std::io::Write that adapts ANSI escape codes to the underlying Writes capabilities

This includes

• Stripping colors for non-terminals
• Respecting env variables like NO_COLOR or CLICOLOR
• (windows) Falling back to the wincon API where ENABLE_VIRTUAL_TERMINAL_PROCESSING is unsupported

You can customize auto-detection by calling into anstyle_query to get a ColorChoice and then calling [AutoStream::new(stream, choice)].

Implementations

impl<S> AutoStream<S>

where S: RawStream,

pub fn new(raw: S, choice: ColorChoice) -> Self

Runtime control over styling behavior

Example

// Like `AutoStream::choice` but without `NO_COLOR`, `CLICOLOR_FORCE`, `CI`
fn choice(raw: &dyn anstream::stream::RawStream) -> anstream::ColorChoice {
    let choice = anstream::ColorChoice::global();
    if choice == anstream::ColorChoice::Auto {
        if raw.is_terminal() && anstyle_query::term_supports_color() {
            anstream::ColorChoice::Always
        } else {
            anstream::ColorChoice::Never
        }
    } else {
        choice
    }
}

let stream = std::io::stdout();
let choice = choice(&stream);
let auto = anstream::AutoStream::new(stream, choice);

pub fn auto(raw: S) -> Self

Auto-adapt for the stream’s capabilities

pub fn choice(raw: &S) -> ColorChoice

Report the desired choice for the given stream

pub fn always_ansi(raw: S) -> Self

Force ANSI escape codes to be passed through as-is, no matter what the inner Write supports.

pub fn always(raw: S) -> Self

Force color, no matter what the inner Write supports.

pub fn never(raw: S) -> Self

Only pass printable data to the inner Write.

pub fn into_inner(self) -> S

Get the wrapped RawStream

pub fn is_terminal(&self) -> bool

Returns true if the descriptor/handle refers to a terminal/tty.

pub fn current_choice(&self) -> ColorChoice

Prefer AutoStream::choice

This doesn’t report what is requested but what is currently active.

impl AutoStream<Stdout>

pub fn lock(self) -> AutoStream<StdoutLock<'static>>

Get exclusive access to the AutoStream

Why?

• Faster performance when writing in a loop
• Avoid other threads interleaving output with the current thread

impl AutoStream<Stderr>

pub fn lock(self) -> AutoStream<StderrLock<'static>>

Get exclusive access to the AutoStream

Why?

• Faster performance when writing in a loop
• Avoid other threads interleaving output with the current thread

Trait Implementations

impl<S: Debug + RawStream> Debug for AutoStream<S>

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

Formats the value using the given formatter.

impl<S> Write for AutoStream<S>

where S: RawStream + AsLockedWrite,

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

Writes a buffer into this writer, returning how many bytes were written.

fn write_vectored(&mut self, bufs: &[IoSlice<'_>]) -> Result<usize>

Like write, except that it writes from a slice of buffers.

fn flush(&mut self) -> Result<()>

Flushes this output stream, ensuring that all intermediately buffered contents reach their destination.

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

Attempts to write an entire buffer into this writer.

fn write_fmt(&mut self, args: Arguments<'_>) -> Result<()>

Writes a formatted string into this writer, returning any error encountered.

fn is_write_vectored(&self) -> bool

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

Determines if this Writer has an efficient write_vectored implementation.

fn write_all_vectored(&mut self, bufs: &mut [IoSlice<'_>]) -> Result<(), Error>

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

Attempts to write multiple buffers into this writer.

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

where Self: Sized,

Creates a “by reference” adapter for this instance of Write.