Files
lazymc/src/util/cli.rs
2023-02-10 11:11:05 +01:00

92 lines
2.5 KiB
Rust

// Allow dead code, until we've fully implemented CLI/error handling
#![allow(dead_code)]
use std::io::{stderr, stdin, Write};
use crate::util::error::{quit_error, ErrorHints};
/// Prompt the user to enter some value.
/// The prompt that is shown should be passed to `msg`,
/// excluding the `:` suffix.
pub fn prompt(msg: &str) -> String {
// Show the prompt
eprint!("{msg}: ");
let _ = stderr().flush();
// Get the input
let mut input = String::new();
if let Err(err) = stdin()
.read_line(&mut input)
.map_err(|err| -> anyhow::Error { err.into() })
{
quit_error(
err.context("failed to read input from prompt"),
ErrorHints::default(),
);
}
// Trim and return
input.trim().to_owned()
}
/// Prompt the user for a question, allowing a yes or now answer.
/// True is returned if yes was answered, false if no.
///
/// A default may be given, which is chosen if no-interact mode is
/// enabled, or if enter was pressed by the user without entering anything.
pub fn prompt_yes(msg: &str, def: Option<bool>) -> bool {
// Define the available options string
let options = format!(
"[{}/{}]",
match def {
Some(def) if def => "Y",
_ => "y",
},
match def {
Some(def) if !def => "N",
_ => "n",
}
);
// Get the user input
let answer = prompt(&format!("{msg} {options}"));
// Assume the default if the answer is empty
if answer.is_empty() {
if let Some(def) = def {
return def;
}
}
// Derive a boolean and return
match derive_bool(&answer) {
Some(answer) => answer,
None => prompt_yes(msg, def),
}
}
/// Try to derive true or false (yes or no) from the given input.
/// None is returned if no boolean could be derived accurately.
fn derive_bool(input: &str) -> Option<bool> {
// Process the input
let input = input.trim().to_lowercase();
// Handle short or incomplete answers
match input.as_str() {
"y" | "ye" | "t" | "1" => return Some(true),
"n" | "f" | "0" => return Some(false),
_ => {}
}
// Handle complete answers with any suffix
if input.starts_with("yes") || input.starts_with("true") {
return Some(true);
}
if input.starts_with("no") || input.starts_with("false") {
return Some(false);
}
// The answer could not be determined, return none
None
}