view rust/hg-cpython/src/dagops.rs @ 44203:2a24ead003f0

rust-cpython: add panicking version of borrow_mut() and use it

The original borrow_mut() is renamed to try_borrow_mut().

Since leak_immutable() no longer incref the borrow count, the caller should
know if the underlying value is borrowed or not. No Python world is involved.
That's why we can simply use the panicking borrow_mut().

// dagops.rs
//
// Copyright 2019 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.

//! Bindings for the `hg::dagops` module provided by the
//! `hg-core` package.
//!
//! From Python, this will be seen as `mercurial.rustext.dagop`
use crate::{conversion::rev_pyiter_collect, exceptions::GraphError};
use cpython::{PyDict, PyModule, PyObject, PyResult, Python};
use hg::dagops;
use hg::Revision;
use std::collections::HashSet;

use crate::revlog::pyindex_to_graph;

/// Using the the `index`, return heads out of any Python iterable of Revisions
///
/// This is the Rust counterpart for `mercurial.dagop.headrevs`
pub fn headrevs(
    py: Python,
    index: PyObject,
    revs: PyObject,
) -> PyResult<HashSet<Revision>> {
    let mut as_set: HashSet<Revision> = rev_pyiter_collect(py, &revs)?;
    dagops::retain_heads(&pyindex_to_graph(py, index)?, &mut as_set)
        .map_err(|e| GraphError::pynew(py, e))?;
    Ok(as_set)
}

/// Create the module, with `__package__` given from parent
pub fn init_module(py: Python, package: &str) -> PyResult<PyModule> {
    let dotted_name = &format!("{}.dagop", package);
    let m = PyModule::new(py, dotted_name)?;
    m.add(py, "__package__", package)?;
    m.add(py, "__doc__", "DAG operations - Rust implementation")?;
    m.add(
        py,
        "headrevs",
        py_fn!(py, headrevs(index: PyObject, revs: PyObject)),
    )?;

    let sys = PyModule::import(py, "sys")?;
    let sys_modules: PyDict = sys.get(py, "modules")?.extract(py)?;
    sys_modules.set_item(py, dotted_name, &m)?;
    // Example C code (see pyexpat.c and import.c) will "give away the
    // reference", but we won't because it will be consumed once the
    // Rust PyObject is dropped.
    Ok(m)
}