view rust/hg-cpython/src/lib.rs @ 51225:89ce6a49bfeb

rust-index: implement common_ancestors_heads() and ancestors()

The only differences betwwen `common_ancestors_heads()` and
`find_gca_candidates()` seems to be that:

- the former accepts "overlapping" input revisions (meaning with duplicates).
- limitation to 24 inputs (in the C code), that we translate to using the
  arbitrary size bit sets in the Rust code because we cannot bail to Python.

Given that the input is expected to be small in most cases, we take the
heavy handed approach of going through a HashSet and wait for perfomance
assessment

In case this is used via `hg-cpython`, we can anyway absorb the overhead
by having `commonancestorheads` build a vector of unique values
directly, and introduce a thin wrapper over `find_gca_candidates`, to take
care of bit set type dispatching only.

As far as `ancestors` is concerneed, this is just chaining
`common_ancestors_heads()` with `find_deepest_revs`.

// 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:
//!
//! ```text
//! >>> from mercurial.rustext import ancestor
//! >>> ancestor.__doc__
//! 'Generic DAG ancestor algorithms - Rust implementation'
//! ```
#![allow(clippy::too_many_arguments)] // rust-cpython macros
#![allow(clippy::zero_ptr)] // rust-cpython macros
#![allow(clippy::needless_update)] // rust-cpython macros
#![allow(clippy::manual_strip)] // rust-cpython macros
#![allow(clippy::type_complexity)] // rust-cpython macros

use cpython::{FromPyObject, PyInt, Python, ToPyObject};
use hg::{BaseRevision, Revision};

/// This crate uses nested private macros, `extern crate` is still needed in
/// 2018 edition.
#[macro_use]
extern crate cpython;

pub mod ancestors;
mod cindex;
mod conversion;
#[macro_use]
pub mod ref_sharing;
pub mod copy_tracing;
pub mod dagops;
pub mod debug;
pub mod dirstate;
pub mod discovery;
pub mod exceptions;
mod pybytes_deref;
pub mod revlog;
pub mod utils;

/// Revision as exposed to/from the Python layer.
///
/// We need this indirection because of the orphan rule, meaning we can't
/// implement a foreign trait (like [`cpython::ToPyObject`])
/// for a foreign type (like [`hg::UncheckedRevision`]).
///
/// This also acts as a deterrent against blindly trusting Python to send
/// us valid revision numbers.
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
pub struct PyRevision(BaseRevision);

impl From<Revision> for PyRevision {
    fn from(r: Revision) -> Self {
        PyRevision(r.0)
    }
}

impl<'s> FromPyObject<'s> for PyRevision {
    fn extract(
        py: Python,
        obj: &'s cpython::PyObject,
    ) -> cpython::PyResult<Self> {
        Ok(Self(obj.extract::<BaseRevision>(py)?))
    }
}

impl ToPyObject for PyRevision {
    type ObjectType = PyInt;

    fn to_py_object(&self, py: Python) -> Self::ObjectType {
        self.0.to_py_object(py)
    }
}

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, "ancestor", ancestors::init_module(py, &dotted_name)?)?;
    m.add(py, "dagop", dagops::init_module(py, &dotted_name)?)?;
    m.add(py, "debug", debug::init_module(py, &dotted_name)?)?;
    m.add(
        py,
        "copy_tracing",
        copy_tracing::init_module(py, &dotted_name)?,
    )?;
    m.add(py, "discovery", discovery::init_module(py, &dotted_name)?)?;
    m.add(py, "dirstate", dirstate::init_module(py, &dotted_name)?)?;
    m.add(py, "revlog", revlog::init_module(py, &dotted_name)?)?;
    m.add(py, "GraphError", py.get_type::<exceptions::GraphError>())?;
    Ok(())
});

#[cfg(not(feature = "python3-bin"))]
#[test]
#[ignore]
fn libpython_must_be_linked_to_run_tests() {
    // stub function to tell that some tests wouldn't run
}