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