use std::{borrow::Cow, convert::TryFrom, path::Path}; /// The error returned by [ask()][crate::ask()].#[derive(Debug, thiserror::Error)]#[allow(missing_docs)]pub enum Error {    #[error("Terminal prompts are disabled")]    Disabled,    #[error("The current platform has no implementation for prompting in the terminal")]    UnsupportedPlatform,    #[error(        "Failed to open terminal at {:?} for writing prompt, or to write it",        crate::unix::TTY_PATH    )]    TtyIo(#[from] std::io::Error),    #[cfg(unix)]    #[error("Failed to obtain or set terminal configuration")]    TerminalConfiguration(#[from] nix::errno::Errno),} /// The way the user is prompted.#[derive(Debug, Copy, Clone, Eq, PartialEq)]pub enum Mode {    /// Visibly show user input.    Visible,    /// Do not show user input, suitable for sensitive data.    Hidden,    /// Do not prompt the user at all but rather abort with an error. This is useful in conjunction with [Options::askpass].    Disable,} impl Default for Mode {    fn default() -> Self {        Mode::Hidden    }} /// The options used in `[ask()]`.#[derive(Default, Clone)]pub struct Options<'a> {    /// The path or name (for lookup in `PATH`) to the askpass program to call before prompting the user.    ///    /// It's called like this `askpass <prompt>`, but note that it won't know if the input should be hidden or not.    pub askpass: Option<Cow<'a, Path>>,    /// The way the user is prompted.    pub mode: Mode,} impl Options<'_> {    /// Change this instance to incorporate information from the environment.    ///    /// - if `use_git_askpass` is true, use `GIT_ASKPASS` to override any existing [`askpass`][Options::askpass] program    /// - otherwise fall back to the [`askpass`][Options::askpass] program already set    /// - or try to use the `SSH_ASKPASS` if `use_ssh_askpass` is true    ///    /// At the and of this process, the `askpass` program may be set depending on the rules above.    ///    /// Lastly, if `use_git_terminal_prompt` is set, use the `GIT_TERMINAL_PROMPT` environment variable and evaluate it as boolean,    /// and if false, set [`mode`][Options::mode] to `disable`.    pub fn apply_environment(        mut self,        use_git_askpass: bool,        use_ssh_askpass: bool,        use_git_terminal_prompt: bool,    ) -> Self {        if let Some(askpass) = use_git_askpass.then(|| std::env::var_os("GIT_ASKPASS")).flatten() {            self.askpass = Some(Cow::Owned(askpass.into()))        }        if self.askpass.is_none() {            if let Some(askpass) = use_ssh_askpass.then(|| std::env::var_os("SSH_ASKPASS")).flatten() {                self.askpass = Some(Cow::Owned(askpass.into()))            }        }        self.mode = use_git_terminal_prompt            .then(|| {                std::env::var_os("GIT_TERMINAL_PROMPT")                    .and_then(|val| git_config_value::Boolean::try_from(val).ok())                    .and_then(|allow| (!allow.0).then_some(Mode::Disable))            })            .flatten()            .unwrap_or(self.mode);        self    }}