rust/chg/src/clientext.rs

rust: translation of missingancestors

This is as direct as possible a translation of the ancestor.missingancestors
Python class in pure Rust. The goal for this changeset is to make it easy
to compare with the Python version.

We also add to Python tests the cases that helped us develop and debug
this implementation.

Some possible optimizations are marked along the way as TODO comments

Differential Revision: https://phab.mercurial-scm.org/D5416

// Copyright 2018 Yuya Nishihara <[e-mail]>
//
// This software may be used and distributed according to the terms of the
// GNU General Public License version 2 or any later version.

//! cHg extensions to command server client.

use std::ffi::OsStr;
use std::os::unix::ffi::OsStrExt;
use std::os::unix::io::AsRawFd;
use std::path::Path;
use tokio_hglib::{Client, Connection};
use tokio_hglib::protocol::OneShotRequest;

use super::attachio::AttachIo;
use super::message;
use super::runcommand::ChgRunCommand;
use super::uihandler::SystemHandler;

pub trait ChgClientExt<C>
    where C: Connection + AsRawFd,
{
    /// Attaches the client file descriptors to the server.
    fn attach_io<I, O, E>(self, stdin: I, stdout: O, stderr: E) -> AttachIo<C, I, O, E>
        where I: AsRawFd,
              O: AsRawFd,
              E: AsRawFd;

    /// Changes the working directory of the server.
    fn set_current_dir<P>(self, dir: P) -> OneShotRequest<C>
        where P: AsRef<Path>;

    /// Runs the specified Mercurial command with cHg extension.
    fn run_command_chg<I, P, H>(self, handler: H, args: I) -> ChgRunCommand<C, H>
        where I: IntoIterator<Item = P>,
              P: AsRef<OsStr>,
              H: SystemHandler;
}

impl<C> ChgClientExt<C> for Client<C>
    where C: Connection + AsRawFd,
{
    fn attach_io<I, O, E>(self, stdin: I, stdout: O, stderr: E) -> AttachIo<C, I, O, E>
        where I: AsRawFd,
              O: AsRawFd,
              E: AsRawFd,
    {
        AttachIo::with_client(self, stdin, stdout, Some(stderr))
    }

    fn set_current_dir<P>(self, dir: P) -> OneShotRequest<C>
        where P: AsRef<Path>,
    {
        OneShotRequest::start_with_args(self, b"chdir", dir.as_ref().as_os_str().as_bytes())
    }

    fn run_command_chg<I, P, H>(self, handler: H, args: I) -> ChgRunCommand<C, H>
        where I: IntoIterator<Item = P>,
              P: AsRef<OsStr>,
              H: SystemHandler,
    {
        ChgRunCommand::with_client(self, handler, message::pack_args_os(args))
    }
}