annotate rust/hg-cpython/src/dirstate/status.rs @ 47093:787ff5d21bcd

dirstate-tree: Make Rust DirstateMap bindings go through a trait object

This changeset starts a series that adds an experiment to make status faster
by changing the dirstate (first only in memory and later also on disk) to
be shaped as a tree matching the directory structure, instead of the current
flat collection of entries. The status algorithm can then traverse this tree
dirstate at the same time as it traverses the filesystem.

We (Octobus) have made prototypes that show promising results but are prone
to bitrot. We would like to start upstreaming some experimental Rust code that
goes in this direction, but to avoid disrupting users it should only be
enabled by some run-time opt-in while keeping the existing dirstate structure
and status algorithm as-is.

The `DirstateMap` type and `status` function look like the appropriate
boundary. This adds a new trait that abstracts everything Python bindings need
and makes those bindings go through a `dyn` trait object. Later we’ll have two
implementations of this trait, and the same bindings can use either.

Differential Revision: https://phab.mercurial-scm.org/D10362

// status.rs
//
// Copyright 2019, Raphaël Gomès <[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::status` module provided by the
//! `hg-core` crate. From Python, this will be seen as
//! `rustext.dirstate.status`.

use crate::{dirstate::DirstateMap, exceptions::FallbackError};
use cpython::exc::OSError;
use cpython::{
    exc::ValueError, ObjectProtocol, PyBytes, PyErr, PyList, PyObject,
    PyResult, PyTuple, Python, PythonObject, ToPyObject,
};
use hg::{
    matchers::{AlwaysMatcher, FileMatcher, IncludeMatcher},
    parse_pattern_syntax,
    utils::{
        files::{get_bytes_from_path, get_path_from_bytes},
        hg_path::{HgPath, HgPathBuf},
    },
    BadMatch, DirstateStatus, IgnorePattern, PatternFileWarning, StatusError,
    StatusOptions,
};
use std::borrow::{Borrow, Cow};

/// This will be useless once trait impls for collection are added to `PyBytes`
/// upstream.
fn collect_pybytes_list(
    py: Python,
    collection: &[impl AsRef<HgPath>],
) -> PyList {
    let list = PyList::new(py, &[]);

    for path in collection.iter() {
        list.append(
            py,
            PyBytes::new(py, path.as_ref().as_bytes()).into_object(),
        )
    }

    list
}

fn collect_bad_matches(
    py: Python,
    collection: &[(impl AsRef<HgPath>, BadMatch)],
) -> PyResult<PyList> {
    let list = PyList::new(py, &[]);

    let os = py.import("os")?;
    let get_error_message = |code: i32| -> PyResult<_> {
        os.call(
            py,
            "strerror",
            PyTuple::new(py, &[code.to_py_object(py).into_object()]),
            None,
        )
    };

    for (path, bad_match) in collection.iter() {
        let message = match bad_match {
            BadMatch::OsError(code) => get_error_message(*code)?,
            BadMatch::BadType(bad_type) => format!(
                "unsupported file type (type is {})",
                bad_type.to_string()
            )
            .to_py_object(py)
            .into_object(),
        };
        list.append(
            py,
            (PyBytes::new(py, path.as_ref().as_bytes()), message)
                .to_py_object(py)
                .into_object(),
        )
    }

    Ok(list)
}

fn handle_fallback(py: Python, err: StatusError) -> PyErr {
    match err {
        StatusError::Pattern(e) => {
            let as_string = e.to_string();
            log::trace!("Rust status fallback: `{}`", &as_string);

            PyErr::new::<FallbackError, _>(py, &as_string)
        }
        StatusError::IO(e) => PyErr::new::<OSError, _>(py, e.to_string()),
        e => PyErr::new::<ValueError, _>(py, e.to_string()),
    }
}

pub fn status_wrapper(
    py: Python,
    dmap: DirstateMap,
    matcher: PyObject,
    root_dir: PyObject,
    ignore_files: PyList,
    check_exec: bool,
    last_normal_time: i64,
    list_clean: bool,
    list_ignored: bool,
    list_unknown: bool,
    collect_traversed_dirs: bool,
) -> PyResult<PyTuple> {
    let bytes = root_dir.extract::<PyBytes>(py)?;
    let root_dir = get_path_from_bytes(bytes.data(py));

    let dmap: DirstateMap = dmap.to_py_object(py);
    let dmap = dmap.get_inner(py);

    let ignore_files: PyResult<Vec<_>> = ignore_files
        .iter(py)
        .map(|b| {
            let file = b.extract::<PyBytes>(py)?;
            Ok(get_path_from_bytes(file.data(py)).to_owned())
        })
        .collect();
    let ignore_files = ignore_files?;

    match matcher.get_type(py).name(py).borrow() {
        "alwaysmatcher" => {
            let matcher = AlwaysMatcher;
            let ((lookup, status_res), warnings) = dmap
                .status(
                    &matcher,
                    root_dir.to_path_buf(),
                    ignore_files,
                    StatusOptions {
                        check_exec,
                        last_normal_time,
                        list_clean,
                        list_ignored,
                        list_unknown,
                        collect_traversed_dirs,
                    },
                )
                .map_err(|e| handle_fallback(py, e))?;
            build_response(py, lookup, status_res, warnings)
        }
        "exactmatcher" => {
            let files = matcher.call_method(
                py,
                "files",
                PyTuple::new(py, &[]),
                None,
            )?;
            let files: PyList = files.cast_into(py)?;
            let files: PyResult<Vec<HgPathBuf>> = files
                .iter(py)
                .map(|f| {
                    Ok(HgPathBuf::from_bytes(
                        f.extract::<PyBytes>(py)?.data(py),
                    ))
                })
                .collect();

            let files = files?;
            let matcher = FileMatcher::new(files.as_ref())
                .map_err(|e| PyErr::new::<ValueError, _>(py, e.to_string()))?;
            let ((lookup, status_res), warnings) = dmap
                .status(
                    &matcher,
                    root_dir.to_path_buf(),
                    ignore_files,
                    StatusOptions {
                        check_exec,
                        last_normal_time,
                        list_clean,
                        list_ignored,
                        list_unknown,
                        collect_traversed_dirs,
                    },
                )
                .map_err(|e| handle_fallback(py, e))?;
            build_response(py, lookup, status_res, warnings)
        }
        "includematcher" => {
            // Get the patterns from Python even though most of them are
            // redundant with those we will parse later on, as they include
            // those passed from the command line.
            let ignore_patterns: PyResult<Vec<_>> = matcher
                .getattr(py, "_kindpats")?
                .iter(py)?
                .map(|k| {
                    let k = k?;
                    let syntax = parse_pattern_syntax(
                        &[
                            k.get_item(py, 0)?
                                .extract::<PyBytes>(py)?
                                .data(py),
                            &b":"[..],
                        ]
                        .concat(),
                    )
                    .map_err(|e| {
                        handle_fallback(py, StatusError::Pattern(e))
                    })?;
                    let pattern = k.get_item(py, 1)?.extract::<PyBytes>(py)?;
                    let pattern = pattern.data(py);
                    let source = k.get_item(py, 2)?.extract::<PyBytes>(py)?;
                    let source = get_path_from_bytes(source.data(py));
                    let new = IgnorePattern::new(syntax, pattern, source);
                    Ok(new)
                })
                .collect();

            let ignore_patterns = ignore_patterns?;
            let mut all_warnings = vec![];

            let (matcher, warnings) =
                IncludeMatcher::new(ignore_patterns, &root_dir)
                    .map_err(|e| handle_fallback(py, e.into()))?;
            all_warnings.extend(warnings);

            let ((lookup, status_res), warnings) = dmap
                .status(
                    &matcher,
                    root_dir.to_path_buf(),
                    ignore_files,
                    StatusOptions {
                        check_exec,
                        last_normal_time,
                        list_clean,
                        list_ignored,
                        list_unknown,
                        collect_traversed_dirs,
                    },
                )
                .map_err(|e| handle_fallback(py, e))?;

            all_warnings.extend(warnings);

            build_response(py, lookup, status_res, all_warnings)
        }
        e => Err(PyErr::new::<ValueError, _>(
            py,
            format!("Unsupported matcher {}", e),
        )),
    }
}

fn build_response(
    py: Python,
    lookup: Vec<Cow<HgPath>>,
    status_res: DirstateStatus,
    warnings: Vec<PatternFileWarning>,
) -> PyResult<PyTuple> {
    let modified = collect_pybytes_list(py, status_res.modified.as_ref());
    let added = collect_pybytes_list(py, status_res.added.as_ref());
    let removed = collect_pybytes_list(py, status_res.removed.as_ref());
    let deleted = collect_pybytes_list(py, status_res.deleted.as_ref());
    let clean = collect_pybytes_list(py, status_res.clean.as_ref());
    let ignored = collect_pybytes_list(py, status_res.ignored.as_ref());
    let unknown = collect_pybytes_list(py, status_res.unknown.as_ref());
    let lookup = collect_pybytes_list(py, lookup.as_ref());
    let bad = collect_bad_matches(py, status_res.bad.as_ref())?;
    let traversed = collect_pybytes_list(py, status_res.traversed.as_ref());
    let py_warnings = PyList::new(py, &[]);
    for warning in warnings.iter() {
        // We use duck-typing on the Python side for dispatch, good enough for
        // now.
        match warning {
            PatternFileWarning::InvalidSyntax(file, syn) => {
                py_warnings.append(
                    py,
                    (
                        PyBytes::new(py, &get_bytes_from_path(&file)),
                        PyBytes::new(py, syn),
                    )
                        .to_py_object(py)
                        .into_object(),
                );
            }
            PatternFileWarning::NoSuchFile(file) => py_warnings.append(
                py,
                PyBytes::new(py, &get_bytes_from_path(&file)).into_object(),
            ),
        }
    }

    Ok(PyTuple::new(
        py,
        &[
            lookup.into_object(),
            modified.into_object(),
            added.into_object(),
            removed.into_object(),
            deleted.into_object(),
            clean.into_object(),
            ignored.into_object(),
            unknown.into_object(),
            py_warnings.into_object(),
            bad.into_object(),
            traversed.into_object(),
        ][..],
    ))
}