rust/hg-cpython/src/discovery.rs

dirstate-map: move most of `dirstate.update_file` logic in the dsmap

A new `reset_state` method is introduced to deal with most of that logic. This
move things one layer lower, but the ultimate goal is to deal with most of this
at the DirstateItem level.

This reveal various imperfection with the data passed to update_file by
`mergestate.recordupdates`, however this is orthogonal to this patch and should
be dealt with at a higher level.

Differential Revision: https://phab.mercurial-scm.org/D11134

// discovery.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.

//! Bindings for the `hg::discovery` module provided by the
//! `hg-core` crate. From Python, this will be seen as `rustext.discovery`
//!
//! # Classes visible from Python:
//! - [`PartialDiscover`] is the Rust implementation of
//!   `mercurial.setdiscovery.partialdiscovery`.

use crate::{
    cindex::Index, conversion::rev_pyiter_collect, exceptions::GraphError,
};
use cpython::{
    ObjectProtocol, PyDict, PyModule, PyObject, PyResult, PyTuple, Python,
    PythonObject, ToPyObject,
};
use hg::discovery::PartialDiscovery as CorePartialDiscovery;
use hg::Revision;
use std::collections::HashSet;

use std::cell::RefCell;

use crate::revlog::pyindex_to_graph;

py_class!(pub class PartialDiscovery |py| {
    data inner: RefCell<Box<CorePartialDiscovery<Index>>>;

    // `_respectsize` is currently only here to replicate the Python API and
    // will be used in future patches inside methods that are yet to be
    // implemented.
    def __new__(
        _cls,
        repo: PyObject,
        targetheads: PyObject,
        respectsize: bool,
        randomize: bool = true
    ) -> PyResult<PartialDiscovery> {
        let index = repo.getattr(py, "changelog")?.getattr(py, "index")?;
        Self::create_instance(
            py,
            RefCell::new(Box::new(CorePartialDiscovery::new(
                pyindex_to_graph(py, index)?,
                rev_pyiter_collect(py, &targetheads)?,
                respectsize,
                randomize,
            )))
        )
    }

    def addcommons(&self, commons: PyObject) -> PyResult<PyObject> {
        let mut inner = self.inner(py).borrow_mut();
        let commons_vec: Vec<Revision> = rev_pyiter_collect(py, &commons)?;
        inner.add_common_revisions(commons_vec)
            .map_err(|e| GraphError::pynew(py, e))?;
        Ok(py.None())
    }

    def addmissings(&self, missings: PyObject) -> PyResult<PyObject> {
        let mut inner = self.inner(py).borrow_mut();
        let missings_vec: Vec<Revision> = rev_pyiter_collect(py, &missings)?;
        inner.add_missing_revisions(missings_vec)
            .map_err(|e| GraphError::pynew(py, e))?;
        Ok(py.None())
    }

    def addinfo(&self, sample: PyObject) -> PyResult<PyObject> {
        let mut missing: Vec<Revision> = Vec::new();
        let mut common: Vec<Revision> = Vec::new();
        for info in sample.iter(py)? { // info is a pair (Revision, bool)
            let mut revknown = info?.iter(py)?;
            let rev: Revision = revknown.next().unwrap()?.extract(py)?;
            let known: bool = revknown.next().unwrap()?.extract(py)?;
            if known {
                common.push(rev);
            } else {
                missing.push(rev);
            }
        }
        let mut inner = self.inner(py).borrow_mut();
        inner.add_common_revisions(common)
            .map_err(|e| GraphError::pynew(py, e))?;
        inner.add_missing_revisions(missing)
            .map_err(|e| GraphError::pynew(py, e))?;
        Ok(py.None())
    }

    def hasinfo(&self) -> PyResult<bool> {
        Ok(self.inner(py).borrow().has_info())
    }

    def iscomplete(&self) -> PyResult<bool> {
        Ok(self.inner(py).borrow().is_complete())
    }

    def stats(&self) -> PyResult<PyDict> {
        let stats = self.inner(py).borrow().stats();
        let as_dict: PyDict = PyDict::new(py);
        as_dict.set_item(py, "undecided",
                         stats.undecided.map(
                             |l| l.to_py_object(py).into_object())
                             .unwrap_or_else(|| py.None()))?;
        Ok(as_dict)
    }

    def commonheads(&self) -> PyResult<HashSet<Revision>> {
        self.inner(py).borrow().common_heads()
            .map_err(|e| GraphError::pynew(py, e))
    }

    def takefullsample(&self, _headrevs: PyObject,
                       size: usize) -> PyResult<PyObject> {
        let mut inner = self.inner(py).borrow_mut();
        let sample = inner.take_full_sample(size)
            .map_err(|e| GraphError::pynew(py, e))?;
        let as_vec: Vec<PyObject> = sample
            .iter()
            .map(|rev| rev.to_py_object(py).into_object())
            .collect();
        Ok(PyTuple::new(py, as_vec.as_slice()).into_object())
    }

    def takequicksample(&self, headrevs: PyObject,
                        size: usize) -> PyResult<PyObject> {
        let mut inner = self.inner(py).borrow_mut();
        let revsvec: Vec<Revision> = rev_pyiter_collect(py, &headrevs)?;
        let sample = inner.take_quick_sample(revsvec, size)
            .map_err(|e| GraphError::pynew(py, e))?;
        let as_vec: Vec<PyObject> = sample
            .iter()
            .map(|rev| rev.to_py_object(py).into_object())
            .collect();
        Ok(PyTuple::new(py, as_vec.as_slice()).into_object())
    }

});

/// Create the module, with __package__ given from parent
pub fn init_module(py: Python, package: &str) -> PyResult<PyModule> {
    let dotted_name = &format!("{}.discovery", package);
    let m = PyModule::new(py, dotted_name)?;
    m.add(py, "__package__", package)?;
    m.add(
        py,
        "__doc__",
        "Discovery of common node sets - Rust implementation",
    )?;
    m.add_class::<PartialDiscovery>(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)
}