annotate rust/hg-cpython/src/lib.rs @ 40965:5532823e8c18

rust-cpython: start cpython crate bindings

This changeset introduces the hg-cpython crate,
that compiles as a shared library holding a whole
Python package (mercurial.rustext), with only the empty
'ancestor' submodule for now.

Such bindings will be easier and safer to develop and maintain
that those of `hg-direct-ffi`.
They don't involve C code, only unsafe Rust that's mostly isolated
within the cpython crate.

The long-term goal would be to import the provided modules, such
as rustext.ancestor with mercurial.policy.importmod, same as
we already do with cext modules.

Differential Revision: https://phab.mercurial-scm.org/D5434

// lib.rs
//
// Copyright 2018 Georges Racinet <[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.

//! Python bindings of `hg-core` objects using the `cpython` crate.
//! Once compiled, the resulting single shared library object can be placed in
//! the `mercurial` package directly as `rustext.so` or `rustext.dll`.
//! It holds several modules, so that from the point of view of Python,
//! it behaves as the `cext` package.
//!
//! Example:
//! ```
//! >>> from mercurial.rustext import ancestor
//! >>> ancestor.__doc__
//! 'Generic DAG ancestor algorithms - Rust implementation'
//! ```

#[macro_use]
extern crate cpython;
extern crate hg;

mod ancestors;
mod exceptions;

py_module_initializer!(rustext, initrustext, PyInit_rustext, |py, m| {
    m.add(
        py,
        "__doc__",
        "Mercurial core concepts - Rust implementation",
    )?;

    let dotted_name: String = m.get(py, "__name__")?.extract(py)?;
    m.add(py, "__package__", "mercurial")?;
    m.add(py, "ancestor", ancestors::init_module(py, &dotted_name)?)?;
    m.add(py, "GraphError", py.get_type::<exceptions::GraphError>())?;
    Ok(())
});