rust-cpython: moved generic conversion fn out of ancestors module
This will allow to use it easily from other submodules
Differential Revision: https://phab.mercurial-scm.org/D5578
// ancestors.rs
//
// Copyright 2018 Georges Racinet <gracinet@anybox.fr>
//
// 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`
//! and can be used as replacement for the the pure `ancestor` Python module.
//!
//! # Classes visible from Python:
//! - [`LazyAncestors`] is the Rust implementation of
//! `mercurial.ancestor.lazyancestors`.
//! The only difference is that it is instantiated with a C `parsers.index`
//! instance instead of a parents function.
//!
//! - [`MissingAncestors`] is the Rust implementation of
//! `mercurial.ancestor.incrementalmissingancestors`.
//!
//! API differences:
//! + it is instantiated with a C `parsers.index`
//! instance instead of a parents function.
//! + `MissingAncestors.bases` is a method returning a tuple instead of
//! a set-valued attribute. We could return a Python set easily if our
//! [PySet PR](https://github.com/dgrunwald/rust-cpython/pull/165)
//! is accepted.
//!
//! - [`AncestorsIterator`] is the Rust counterpart of the
//! `ancestor._lazyancestorsiter` Python generator.
//! From Python, instances of this should be mainly obtained by calling
//! `iter()` on a [`LazyAncestors`] instance.
//!
//! [`LazyAncestors`]: struct.LazyAncestors.html
//! [`MissingAncestors`]: struct.MissingAncestors.html
//! [`AncestorsIterator`]: struct.AncestorsIterator.html
use crate::conversion::rev_pyiter_collect;
use cindex::Index;
use cpython::{
ObjectProtocol, PyClone, PyDict, PyList, PyModule, PyObject,
PyResult, PyTuple, Python, PythonObject, ToPyObject,
};
use exceptions::GraphError;
use hg::Revision;
use hg::{
AncestorsIterator as CoreIterator, LazyAncestors as CoreLazy,
MissingAncestors as CoreMissing,
};
use std::cell::RefCell;
use std::collections::HashSet;
py_class!(pub class AncestorsIterator |py| {
data inner: RefCell<Box<CoreIterator<Index>>>;
def __next__(&self) -> PyResult<Option<Revision>> {
match self.inner(py).borrow_mut().next() {
Some(Err(e)) => Err(GraphError::pynew(py, e)),
None => Ok(None),
Some(Ok(r)) => Ok(Some(r)),
}
}
def __contains__(&self, rev: Revision) -> PyResult<bool> {
self.inner(py).borrow_mut().contains(rev)
.map_err(|e| GraphError::pynew(py, e))
}
def __iter__(&self) -> PyResult<Self> {
Ok(self.clone_ref(py))
}
def __new__(_cls, index: PyObject, initrevs: PyObject, stoprev: Revision,
inclusive: bool) -> PyResult<AncestorsIterator> {
let initvec: Vec<Revision> = rev_pyiter_collect(py, &initrevs)?;
let ait = CoreIterator::new(
Index::new(py, index)?,
initvec,
stoprev,
inclusive,
)
.map_err(|e| GraphError::pynew(py, e))?;
AncestorsIterator::from_inner(py, ait)
}
});
impl AncestorsIterator {
pub fn from_inner(py: Python, ait: CoreIterator<Index>) -> PyResult<Self> {
Self::create_instance(py, RefCell::new(Box::new(ait)))
}
}
py_class!(pub class LazyAncestors |py| {
data inner: RefCell<Box<CoreLazy<Index>>>;
def __contains__(&self, rev: Revision) -> PyResult<bool> {
self.inner(py)
.borrow_mut()
.contains(rev)
.map_err(|e| GraphError::pynew(py, e))
}
def __iter__(&self) -> PyResult<AncestorsIterator> {
AncestorsIterator::from_inner(py, self.inner(py).borrow().iter())
}
def __bool__(&self) -> PyResult<bool> {
Ok(!self.inner(py).borrow().is_empty())
}
def __new__(_cls, index: PyObject, initrevs: PyObject, stoprev: Revision,
inclusive: bool) -> PyResult<Self> {
let initvec: Vec<Revision> = rev_pyiter_collect(py, &initrevs)?;
let lazy =
CoreLazy::new(Index::new(py, index)?, initvec, stoprev, inclusive)
.map_err(|e| GraphError::pynew(py, e))?;
Self::create_instance(py, RefCell::new(Box::new(lazy)))
}
});
py_class!(pub class MissingAncestors |py| {
data inner: RefCell<Box<CoreMissing<Index>>>;
def __new__(_cls, index: PyObject, bases: PyObject) -> PyResult<MissingAncestors> {
let bases_vec: Vec<Revision> = rev_pyiter_collect(py, &bases)?;
let inner = CoreMissing::new(Index::new(py, index)?, bases_vec);
MissingAncestors::create_instance(py, RefCell::new(Box::new(inner)))
}
def hasbases(&self) -> PyResult<bool> {
Ok(self.inner(py).borrow().has_bases())
}
def addbases(&self, bases: PyObject) -> PyResult<PyObject> {
let mut inner = self.inner(py).borrow_mut();
let bases_vec: Vec<Revision> = rev_pyiter_collect(py, &bases)?;
inner.add_bases(bases_vec);
// cpython doc has examples with PyResult<()> but this gives me
// the trait `cpython::ToPyObject` is not implemented for `()`
// so let's return an explicit None
Ok(py.None())
}
def bases(&self) -> PyResult<PyTuple> {
let inner = self.inner(py).borrow();
let bases_set = inner.get_bases();
// convert as Python tuple TODO how to return a proper Python set?
let mut bases_vec: Vec<PyObject> = Vec::with_capacity(
bases_set.len());
for rev in bases_set {
bases_vec.push(rev.to_py_object(py).into_object());
}
Ok(PyTuple::new(py, bases_vec.as_slice()))
}
def removeancestorsfrom(&self, revs: PyObject) -> PyResult<PyObject> {
let mut inner = self.inner(py).borrow_mut();
// this is very lame: we convert to a Rust set, update it in place
// and then convert back to Python, only to have Python remove the
// excess (thankfully, Python is happy with a list or even an iterator)
// Leads to improve this:
// - have the CoreMissing instead do something emit revisions to
// discard
// - define a trait for sets of revisions in the core and implement
// it for a Python set rewrapped with the GIL marker
let mut revs_pyset: HashSet<Revision> = rev_pyiter_collect(py, &revs)?;
inner.remove_ancestors_from(&mut revs_pyset)
.map_err(|e| GraphError::pynew(py, e))?;
// convert as Python list
let mut remaining_pyint_vec: Vec<PyObject> = Vec::with_capacity(
revs_pyset.len());
for rev in revs_pyset {
remaining_pyint_vec.push(rev.to_py_object(py).into_object());
}
let remaining_pylist = PyList::new(py, remaining_pyint_vec.as_slice());
revs.call_method(py, "intersection_update", (remaining_pylist, ), None)
}
def missingancestors(&self, revs: PyObject) -> PyResult<PyList> {
let mut inner = self.inner(py).borrow_mut();
let revs_vec: Vec<Revision> = rev_pyiter_collect(py, &revs)?;
let missing_vec = match inner.missing_ancestors(revs_vec) {
Ok(missing) => missing,
Err(e) => {
return Err(GraphError::pynew(py, e));
}
};
// convert as Python list
let mut missing_pyint_vec: Vec<PyObject> = Vec::with_capacity(
missing_vec.len());
for rev in missing_vec {
missing_pyint_vec.push(rev.to_py_object(py).into_object());
}
Ok(PyList::new(py, missing_pyint_vec.as_slice()))
}
});
/// Create the module, with __package__ given from parent
pub fn init_module(py: Python, package: &str) -> PyResult<PyModule> {
let dotted_name = &format!("{}.ancestor", package);
let m = PyModule::new(py, dotted_name)?;
m.add(py, "__package__", package)?;
m.add(
py,
"__doc__",
"Generic DAG ancestor algorithms - Rust implementation",
)?;
m.add_class::<AncestorsIterator>(py)?;
m.add_class::<LazyAncestors>(py)?;
m.add_class::<MissingAncestors>(py)?;
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)
}