rust/rhg/src/main.rs

extern crate log;
use clap::App;
use clap::AppSettings;
use clap::Arg;
use clap::ArgGroup;
use clap::ArgMatches;
use clap::SubCommand;
use hg::operations::DebugDataKind;
use std::convert::TryFrom;

mod commands;
mod error;
mod exitcode;
mod ui;
use commands::Command;
use error::CommandError;

fn main() {
    env_logger::init();
    let app = App::new("rhg")
        .setting(AppSettings::AllowInvalidUtf8)
        .setting(AppSettings::SubcommandRequired)
        .setting(AppSettings::VersionlessSubcommands)
        .version("0.0.1")
        .subcommand(
            SubCommand::with_name("root").about(commands::root::HELP_TEXT),
        )
        .subcommand(
            SubCommand::with_name("files").about(commands::files::HELP_TEXT),
        )
        .subcommand(
            SubCommand::with_name("debugdata")
                .about(commands::debugdata::HELP_TEXT)
                .arg(
                    Arg::with_name("changelog")
                        .help("open changelog")
                        .short("-c")
                        .long("--changelog"),
                )
                .arg(
                    Arg::with_name("manifest")
                        .help("open manifest")
                        .short("-m")
                        .long("--manifest"),
                )
                .group(
                    ArgGroup::with_name("")
                        .args(&["changelog", "manifest"])
                        .required(true),
                )
                .arg(
                    Arg::with_name("rev")
                        .help("revision")
                        .required(true)
                        .value_name("REV"),
                ),
        );

    let matches = app.clone().get_matches_safe().unwrap_or_else(|err| {
        let _ = ui::Ui::new().writeln_stderr_str(&err.message);
        std::process::exit(exitcode::UNIMPLEMENTED_COMMAND)
    });

    let ui = ui::Ui::new();

    let command_result = match_subcommand(matches, &ui);

    match command_result {
        Ok(_) => std::process::exit(exitcode::OK),
        Err(e) => {
            let message = e.get_error_message_bytes();
            if let Some(msg) = message {
                match ui.write_stderr(&msg) {
                    Ok(_) => (),
                    Err(_) => std::process::exit(exitcode::ABORT),
                };
            };
            e.exit()
        }
    }
}

fn match_subcommand(
    matches: ArgMatches,
    ui: &ui::Ui,
) -> Result<(), CommandError> {
    match matches.subcommand() {
        ("root", _) => commands::root::RootCommand::new().run(&ui),
        ("files", _) => commands::files::FilesCommand::new().run(&ui),
        ("debugdata", Some(matches)) => {
            commands::debugdata::DebugDataCommand::try_from(matches)?.run(&ui)
        }
        _ => unreachable!(), // Because of AppSettings::SubcommandRequired,
    }
}

impl<'a> TryFrom<&'a ArgMatches<'_>>
    for commands::debugdata::DebugDataCommand<'a>
{
    type Error = CommandError;

    fn try_from(args: &'a ArgMatches) -> Result<Self, Self::Error> {
        let rev = args
            .value_of("rev")
            .expect("rev should be a required argument");
        let kind = match (
            args.is_present("changelog"),
            args.is_present("manifest"),
        ) {
            (true, false) => DebugDataKind::Changelog,
            (false, true) => DebugDataKind::Manifest,
            (true, true) => {
                unreachable!("Should not happen since options are exclusive")
            }
            (false, false) => {
                unreachable!("Should not happen since options are required")
            }
        };
        Ok(commands::debugdata::DebugDataCommand::new(rev, kind))
    }
}