Struct Chrome 

pub struct Chrome<W: Write> { /* private fields */ }

The terminal’s decorations, and the promise to undo them.

Generic over its sink so the sequences are assertable. That is not a courtesy to the tests: every one of these writes is invisible to every other kind of test — a title that is never restored, a progress bar left at 41% forever, a frame that begins a synchronized update and never ends it — and the last of those leaves the reader looking at a frozen screen.

Implementations

impl<W: Write> Chrome<W>

pub fn new(out: W, decor: Decor) -> Self

A chrome that writes what decor allows, and nothing else, to out.

pub fn enter(&mut self) -> Result<()>

Takes the states that have to be given back: the title, and focus reporting.

Focus reporting is only asked for when a notification could actually be sent, because it is the answer to exactly one question — is anybody looking — and a terminal that cannot show a notification is not being asked it.

The flag is set before the writes rather than after each one, which is the opposite of [super::Restore]’s rule and deliberate: a half-written enter leaves the terminal in a state this cannot know, and of the two ways to be wrong, undoing something that never happened costs five bytes at a terminal already being restored while skipping the undo leaves a shell answering every click with escape gibberish.

Errors

Anything the terminal refuses.

pub fn begin_frame(&mut self) -> Result<()>

Opens a synchronized update. Everything drawn until Chrome::end_frame lands at once.

Errors

Anything the terminal refuses.

pub fn end_frame(&mut self) -> Result<()>

Closes it. Must run even when the draw between the two failed.

Errors

Anything the terminal refuses.

pub fn show(&mut self, status: Status) -> Result<()>

Says where the run has got to, writing only what changed.

Errors

Anything the terminal refuses.

pub fn focused(&mut self, here: bool)

What the terminal reported about the reader’s attention.

pub fn announce(&mut self, body: &str, took: Duration) -> Result<()>

Tells the reader something finished, if they are not here to see it and it took long enough to be worth saying.

Errors

Anything the terminal refuses.

pub fn failed(&mut self)

Records that the run is ending without having done everything it was asked.

The bar says so rather than simply going out, because the reader who wanted a bar is by definition the reader who is not looking at the exit status.

pub fn restore(&mut self) -> Result<()>

Puts back everything this took, and can be called twice.

Idempotent because it runs from two places by design: the ordinary way out, and the guard that owns it being dropped by a ? or a panic. Every step is attempted and the first refusal reported, for [super::Restore]’s reason — a terminal half restored is no better than one not restored at all, and a failing call says nothing about whether the next would.

Errors

The first thing the terminal refused.

Trait Implementations

impl<W: Debug + Write> Debug for Chrome<W>

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

Formats the value using the given formatter.