rust/rhg/src/commands/cat.rs

rhg: Group values passed to every sub-command into a struct

The set of which values this is is evidently not stable yet,
so this will make changes easier. Also it is growing, and the function
signatures are getting out hand.

Differential Revision: https://phab.mercurial-scm.org/D10003

use crate::error::CommandError;
use clap::Arg;
use hg::operations::cat;
use hg::repo::Repo;
use hg::utils::hg_path::HgPathBuf;
use micro_timer::timed;
use std::convert::TryFrom;

pub const HELP_TEXT: &str = "
Output the current or given revision of files
";

pub fn args() -> clap::App<'static, 'static> {
    clap::SubCommand::with_name("cat")
        .arg(
            Arg::with_name("rev")
                .help("search the repository as it is in REV")
                .short("-r")
                .long("--revision")
                .value_name("REV")
                .takes_value(true),
        )
        .arg(
            clap::Arg::with_name("files")
                .required(true)
                .multiple(true)
                .empty_values(false)
                .value_name("FILE")
                .help("Activity to start: activity@category"),
        )
        .about(HELP_TEXT)
}

#[timed]
pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {
    let rev = invocation.subcommand_args.value_of("rev");
    let file_args = match invocation.subcommand_args.values_of("files") {
        Some(files) => files.collect(),
        None => vec![],
    };

    let repo = Repo::find(invocation.non_repo_config, invocation.repo_path)?;
    let cwd = hg::utils::current_dir()?;

    let mut files = vec![];
    for file in file_args.iter() {
        // TODO: actually normalize `..` path segments etc?
        let normalized = cwd.join(&file);
        let stripped = normalized
            .strip_prefix(&repo.working_directory_path())
            // TODO: error message for path arguments outside of the repo
            .map_err(|_| CommandError::abort(""))?;
        let hg_file = HgPathBuf::try_from(stripped.to_path_buf())
            .map_err(|e| CommandError::abort(e.to_string()))?;
        files.push(hg_file);
    }

    match rev {
        Some(rev) => {
            let data = cat(&repo, rev, &files).map_err(|e| (e, rev))?;
            invocation.ui.write_stdout(&data)?;
            Ok(())
        }
        None => Err(CommandError::Unimplemented.into()),
    }
}