decomp-toolkit/src/argh_version.rs

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// From https://gist.github.com/suluke/e0c672492126be0a4f3b4f0e1115d77c
//! Extend `argh` to be better integrated with the `cargo` ecosystem
//!
//! For now, this only adds a --version/-V option which causes early-exit.
use argh::{FromArgs, TopLevelCommand};
struct ArgsOrVersion<T: FromArgs>(T);
impl<T> TopLevelCommand for ArgsOrVersion<T> where T: FromArgs {}
impl<T> FromArgs for ArgsOrVersion<T>
where T: FromArgs
{
fn from_args(command_name: &[&str], args: &[&str]) -> Result<Self, argh::EarlyExit> {
/// Also use argh for catching `--version`-only invocations
#[derive(FromArgs)]
struct Version {
/// print version information and exit
#[argh(switch, short = 'V')]
pub version: bool,
}
match Version::from_args(command_name, args) {
Ok(v) => {
if v.version {
Err(argh::EarlyExit {
output: format!(
"{} {} {}",
command_name.first().unwrap_or(&""),
env!("CARGO_PKG_VERSION"),
env!("GIT_COMMIT_SHA"),
),
status: Ok(()),
})
} else {
// seems args are empty
T::from_args(command_name, args).map(Self)
}
}
Err(exit) => match exit.status {
Ok(()) => {
// must have been --help
let help = match T::from_args(command_name, &["--help"]) {
Ok(_) => unreachable!(),
Err(exit) => exit.output,
};
Err(argh::EarlyExit {
output: format!(
"{help} -V, --version print version information and exit"
),
status: Ok(()),
})
}
Err(()) => T::from_args(command_name, args).map(Self),
},
}
}
}
/// Create a `FromArgs` type from the current processs `env::args`.
///
/// This function will exit early from the current process if argument parsing was unsuccessful or if information like `--help` was requested.
/// Error messages will be printed to stderr, and `--help` output to stdout.
pub fn from_env<T>() -> T
where T: TopLevelCommand {
argh::from_env::<ArgsOrVersion<T>>().0
}