annotate rust/hg-cpython/src/conversion.rs @ 51479:5bd31e68c7a3

stream-clone-test: add title to various test cases

These case are fine as is, but as we are adding title to all the other as we
simplify them, lets add title for all cases.

// conversion.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::ancestors module provided by the
//! `hg-core` crate. From Python, this will be seen as `rustext.ancestor`

use cpython::{ObjectProtocol, PyErr, PyObject, PyResult, Python};
use hg::{Revision, RevlogIndex, UncheckedRevision};

use crate::{exceptions::GraphError, PyRevision};

/// Utility function to convert a Python iterable into various collections
///
/// We need this in particular to feed to various methods of inner objects
/// with `impl IntoIterator<Item=Revision>` arguments, because
/// a `PyErr` can arise at each step of iteration, whereas these methods
/// expect iterables over `Revision`, not over some `Result<Revision, PyErr>`
pub fn rev_pyiter_collect<C, I>(
    py: Python,
    revs: &PyObject,
    index: &I,
) -> PyResult<C>
where
    C: FromIterator<Revision>,
    I: RevlogIndex,
{
    rev_pyiter_collect_or_else(py, revs, index, |r| {
        PyErr::new::<GraphError, _>(py, ("InvalidRevision", r.0))
    })
}

/// Same as [`rev_pyiter_collect`], giving control on returned errors
pub fn rev_pyiter_collect_or_else<C, I>(
    py: Python,
    revs: &PyObject,
    index: &I,
    invalid_rev_error: impl FnOnce(PyRevision) -> PyErr + Copy,
) -> PyResult<C>
where
    C: FromIterator<Revision>,
    I: RevlogIndex,
{
    revs.iter(py)?
        .map(|r| {
            r.and_then(|o| match o.extract::<PyRevision>(py) {
                Ok(r) => index
                    .check_revision(UncheckedRevision(r.0))
                    .ok_or_else(|| invalid_rev_error(r)),
                Err(e) => Err(e),
            })
        })
        .collect()
}