view rust/rhg/src/commands/config.rs @ 48495:e293ff808a05

rhg: Use binary search in manifest lookup

… instead of linear scan, when looking for a single entry based on its path.
Manifest entries are sorted by path, but are variable-size so we can’t use
the standard library’s `[T]::binary_search`. We can still jump to a byte
index and then look around for entry boundaries.

Differential Revision: https://phab.mercurial-scm.org/D11932

use crate::error::CommandError;
use clap::Arg;
use format_bytes::format_bytes;
use hg::errors::HgError;
use hg::utils::SliceExt;

pub const HELP_TEXT: &str = "
With one argument of the form section.name, print just the value of that config item.
";

pub fn args() -> clap::App<'static, 'static> {
    clap::SubCommand::with_name("config")
        .arg(
            Arg::with_name("name")
                .help("the section.name to print")
                .value_name("NAME")
                .required(true)
                .takes_value(true),
        )
        .about(HELP_TEXT)
}

pub fn run(invocation: &crate::CliInvocation) -> Result<(), CommandError> {
    let (section, name) = invocation
        .subcommand_args
        .value_of("name")
        .expect("missing required CLI argument")
        .as_bytes()
        .split_2(b'.')
        .ok_or_else(|| HgError::unsupported("hg config <section>"))?;

    if let Some(value) = invocation.config.get(section, name) {
        invocation.ui.write_stdout(&format_bytes!(b"{}\n", value))?;
        Ok(())
    } else {
        Err(CommandError::Unsuccessful)
    }
}