use std::io::Read; use crate::helper::{Action, Context, Error, NextAction, Outcome, Result}; impl Action {    /// Send ourselves to the given `write` which is expected to be credentials-helper compatible    pub fn send(&self, mut write: impl std::io::Write) -> std::io::Result<()> {        match self {            Action::Get(ctx) => ctx.write_to(write),            Action::Store(last) | Action::Erase(last) => {                write.write_all(last)?;                write.write_all(&[b'\n'])            }        }    }} /// Invoke the given `helper` with `action` in `context`.////// Usually the first call is performed with [`Action::Get`] to obtain `Some` identity, which subsequently can be used if it is complete./// Note that it may also only contain the username _or_ password, and should start out with everything the helper needs./// On successful usage, use [`NextAction::store()`], otherwise [`NextAction::erase()`], which is when this function/// returns `Ok(None)` as no outcome is expected.pub fn invoke(helper: &mut crate::Program, action: &Action) -> Result {    match raw(helper, action)? {        None => Ok(None),        Some(stdout) => {            let ctx = Context::from_bytes(stdout.as_slice())?;            Ok(Some(Outcome {                username: ctx.username,                password: ctx.password,                quit: ctx.quit.unwrap_or(false),                next: NextAction {                    previous_output: stdout.into(),                },            }))        }    }} pub(crate) fn raw(helper: &mut crate::Program, action: &Action) -> std::result::Result<Option<Vec<u8>>, Error> {    let (stdin, stdout) = helper.start(action)?;    if let (Action::Get(_), None) = (&action, &stdout) {        panic!("BUG: `Helper` impls must return an output handle to read output from if Action::Get is provided")    }    action.send(stdin)?;    let stdout = stdout        .map(|mut stdout| {            let mut buf = Vec::new();            stdout.read_to_end(&mut buf).map(|_| buf)        })        .transpose()        .map_err(|err| Error::CredentialsHelperFailed { source: err })?;    helper.finish().map_err(|err| {        if err.kind() == std::io::ErrorKind::Other {            Error::CredentialsHelperFailed { source: err }        } else {            err.into()        }    })?;     match matches!(action, Action::Get(_)).then(|| stdout).flatten() {        None => Ok(None),        Some(stdout) => Ok(Some(stdout)),    }}