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rust-index: using `hg::index::Index` in MissingAncestors...
rust-index: using `hg::index::Index` in MissingAncestors With this, the whole `hg-cpython::ancestors` module can now work without the C index.

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ancestors.rs
392 lines | 13.6 KiB | application/rls-services+xml | RustLexer
// 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::revlog::py_rust_index_to_graph;
use crate::PyRevision;
use crate::{
conversion::rev_pyiter_collect, exceptions::GraphError,
revlog::PySharedIndex,
};
use cpython::{
ObjectProtocol, PyClone, PyDict, PyErr, PyList, PyModule, PyObject,
PyResult, Python, PythonObject, ToPyObject, UnsafePyLeaked,
};
use hg::MissingAncestors as CoreMissing;
use hg::Revision;
use std::cell::RefCell;
use std::collections::HashSet;
use vcsgraph::lazy_ancestors::{
AncestorsIterator as VCGAncestorsIterator,
LazyAncestors as VCGLazyAncestors,
};
// Error propagation for an [`UnsafePyLeaked`] wrapping a [`Result`]
//
// It would be nice for UnsharedPyLeaked to provide this directly as a variant
// of the `map` method with a signature such as:
//
// ```
// unafe fn map_or_err(py: Python,
// f: impl FnOnce(T) -> Result(U, E),
// convert_err: impl FnOnce(Python, E) -> PyErr)
// ```
//
// This would spare users of the `cpython` crate the additional `unsafe` deref
// to inspect the error and return it outside `UnsafePyLeaked`, and the
// subsequent unwrapping that this function performs.
fn pyleaked_or_map_err<T, E: std::fmt::Debug + Copy>(
py: Python,
leaked: UnsafePyLeaked<Result<T, E>>,
convert_err: impl FnOnce(Python, E) -> PyErr,
) -> PyResult<UnsafePyLeaked<T>> {
// Result.inspect_err is unstable in Rust 1.61
if let Err(e) = *unsafe { leaked.try_borrow(py)? } {
return Err(convert_err(py, e));
}
Ok(unsafe {
leaked.map(py, |res| {
res.expect("Error case should have already be treated")
})
})
}
py_class!(pub class AncestorsIterator |py| {
data inner: RefCell<UnsafePyLeaked<VCGAncestorsIterator<PySharedIndex>>>;
def __next__(&self) -> PyResult<Option<PyRevision>> {
let mut leaked = self.inner(py).borrow_mut();
let mut inner = unsafe { leaked.try_borrow_mut(py)? };
match inner.next() {
Some(Err(e)) => Err(GraphError::pynew_from_vcsgraph(py, e)),
None => Ok(None),
Some(Ok(r)) => Ok(Some(PyRevision(r))),
}
}
def __contains__(&self, rev: PyRevision) -> PyResult<bool> {
let mut leaked = self.inner(py).borrow_mut();
let mut inner = unsafe { leaked.try_borrow_mut(py)? };
inner.contains(rev.0)
.map_err(|e| GraphError::pynew_from_vcsgraph(py, e))
}
def __iter__(&self) -> PyResult<Self> {
Ok(self.clone_ref(py))
}
def __new__(
_cls,
index: PyObject,
initrevs: PyObject,
stoprev: PyRevision,
inclusive: bool
) -> PyResult<AncestorsIterator> {
Self::inner_new(py, index, initrevs, stoprev, inclusive)
}
});
impl AncestorsIterator {
pub fn from_inner(
py: Python,
ait: UnsafePyLeaked<VCGAncestorsIterator<PySharedIndex>>,
) -> PyResult<Self> {
Self::create_instance(py, RefCell::new(ait))
}
pub fn inner_new(
py: Python,
index: PyObject,
initrevs: PyObject,
stoprev: PyRevision,
inclusive: bool,
) -> PyResult<AncestorsIterator> {
let index = py_rust_index_to_graph(py, index)?;
let initvec: Vec<_> = {
let borrowed_idx = unsafe { index.try_borrow(py)? };
rev_pyiter_collect(py, &initrevs, &*borrowed_idx)?
};
let res_ait = unsafe {
index.map(py, |idx| {
VCGAncestorsIterator::new(
idx,
initvec.into_iter().map(|r| r.0),
stoprev.0,
inclusive,
)
})
};
let ait =
pyleaked_or_map_err(py, res_ait, GraphError::pynew_from_vcsgraph)?;
AncestorsIterator::from_inner(py, ait)
}
}
py_class!(pub class LazyAncestors |py| {
data inner: RefCell<UnsafePyLeaked<
RefCell<VCGLazyAncestors<PySharedIndex>>
>>;
data index: PyObject;
data initrevs: PyObject;
data stoprev: PyRevision;
data inclusive: bool;
def __contains__(&self, rev: PyRevision) -> PyResult<bool> {
let leaked = self.inner(py).borrow();
let inner: &RefCell<VCGLazyAncestors<PySharedIndex>> =
&*unsafe { leaked.try_borrow(py)? };
let inner_mut: &mut VCGLazyAncestors<PySharedIndex> =
&mut *inner.borrow_mut();
inner_mut.contains(rev.0)
.map_err(|e| GraphError::pynew_from_vcsgraph(py, e))
}
def __iter__(&self) -> PyResult<AncestorsIterator> {
let index = self.index(py).clone_ref(py);
let initrevs = self.initrevs(py).clone_ref(py);
AncestorsIterator::inner_new(py, index, initrevs,
*self.stoprev(py),
*self.inclusive(py))
}
def __bool__(&self) -> PyResult<bool> {
let leaked = self.inner(py).borrow();
let inner = unsafe { leaked.try_borrow(py)? };
let empty = inner.borrow().is_empty();
Ok(!empty)
}
def __new__(
_cls,
index: PyObject,
initrevs: PyObject,
stoprev: PyRevision,
inclusive: bool
) -> PyResult<Self> {
let cloned_index = index.clone_ref(py);
let index = py_rust_index_to_graph(py, index)?;
let initvec: Vec<_> = {
let borrowed_idx = unsafe {index.try_borrow(py)?};
rev_pyiter_collect(py, &initrevs, &*borrowed_idx)?
};
let res_lazy =
unsafe { index.map(py, |idx| VCGLazyAncestors::new(
idx,
initvec.into_iter().map(|r| r.0),
stoprev.0,
inclusive
))};
let lazy = pyleaked_or_map_err(py, res_lazy,
GraphError::pynew_from_vcsgraph)?;
let lazy_cell = unsafe { lazy.map(py, RefCell::new)};
let res = Self::create_instance(
py, RefCell::new(lazy_cell),
cloned_index, initrevs, stoprev, inclusive)?;
Ok(res)
}
});
py_class!(pub class MissingAncestors |py| {
data inner: RefCell<UnsafePyLeaked<
CoreMissing<PySharedIndex>
>>;
data index: PyObject;
def __new__(
_cls,
index: PyObject,
bases: PyObject
)
-> PyResult<MissingAncestors> {
let cloned_index = index.clone_ref(py);
let inner_index = py_rust_index_to_graph(py, index)?;
let bases_vec: Vec<_> = {
let borrowed_idx = unsafe { inner_index.try_borrow(py)? };
rev_pyiter_collect(py, &bases, &*borrowed_idx)?
};
let inner = unsafe {
inner_index.map(py, |idx| CoreMissing::new(idx, bases_vec))
};
MissingAncestors::create_instance(
py,
RefCell::new(inner),
cloned_index,
)
}
def hasbases(&self) -> PyResult<bool> {
let leaked = self.inner(py).borrow();
let inner: &CoreMissing<PySharedIndex> =
&*unsafe { leaked.try_borrow(py)? };
Ok(inner.has_bases())
}
def addbases(&self, bases: PyObject) -> PyResult<PyObject> {
let bases_vec: Vec<_> = {
let leaked = py_rust_index_to_graph(py,
self.index(py).clone_ref(py))?;
let index = &*unsafe { leaked.try_borrow(py)? };
rev_pyiter_collect(py, &bases, index)?
};
let mut leaked = self.inner(py).borrow_mut();
let inner: &mut CoreMissing<PySharedIndex> =
&mut *unsafe { leaked.try_borrow_mut(py)? };
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<HashSet<PyRevision>> {
let leaked = self.inner(py).borrow();
let inner: &CoreMissing<PySharedIndex> =
&*unsafe { leaked.try_borrow(py)? };
Ok(inner.get_bases()
.iter()
.map(|r| PyRevision(r.0))
.collect()
)
}
def basesheads(&self) -> PyResult<HashSet<PyRevision>> {
let leaked = self.inner(py).borrow();
let inner: &CoreMissing<PySharedIndex> =
&*unsafe { leaked.try_borrow(py)? };
Ok(
inner
.bases_heads()
.map_err(|e| GraphError::pynew(py, e))?
.into_iter()
.map(|r| PyRevision(r.0))
.collect()
)
}
def removeancestorsfrom(&self, revs: PyObject) -> PyResult<PyObject> {
let mut revs_pyset: HashSet<Revision> = {
// 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 leaked = py_rust_index_to_graph(py,
self.index(py).clone_ref(py))?;
let index = &*unsafe { leaked.try_borrow(py)? };
rev_pyiter_collect(py, &revs, &*index)?
};
let mut leaked = self.inner(py).borrow_mut();
let inner: &mut CoreMissing<PySharedIndex> =
&mut *unsafe { leaked.try_borrow_mut(py)? };
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(
PyRevision(rev.0).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 revs_vec: Vec<Revision> = {
let leaked = py_rust_index_to_graph(py,
self.index(py).clone_ref(py))?;
let index = &*unsafe { leaked.try_borrow(py)? };
rev_pyiter_collect(py, &revs, index)?
};
let mut leaked = self.inner(py).borrow_mut();
let inner: &mut CoreMissing<PySharedIndex> =
&mut *unsafe { leaked.try_borrow_mut(py)? };
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(
PyRevision(rev.0).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)
}