rust/hg-cpython/src/dirstate.rs

branchmap: update rev-branch-cache incrementally

Historically, the revision to branch mapping cache was updated on demand
and shared via bundle2 to avoid the cost of rebuilding on first use.

Use the new `register_changeset` callback and update rbc directly on
every change. Make the transfer of the bundle part redundant, but keep
it for the moment to avoid the test churn.

Over all, "hg unbundle" for large bundles is less than 1.8% slower for
different larger repositories and that seems to a reasonable trade off.

Differential Revision: https://phab.mercurial-scm.org/D9781

// dirstate.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::dirstate` module provided by the
//! `hg-core` package.
//!
//! From Python, this will be seen as `mercurial.rustext.dirstate`
mod copymap;
mod dirs_multiset;
mod dirstate_map;
mod non_normal_entries;
mod status;
use crate::{
    dirstate::{
        dirs_multiset::Dirs, dirstate_map::DirstateMap, status::status_wrapper,
    },
    exceptions,
};
use cpython::{
    exc, PyBytes, PyDict, PyErr, PyList, PyModule, PyObject, PyResult,
    PySequence, Python,
};
use hg::{
    utils::hg_path::HgPathBuf, DirstateEntry, DirstateParseError, EntryState,
    StateMap,
};
use libc::{c_char, c_int};
use std::convert::TryFrom;

// C code uses a custom `dirstate_tuple` type, checks in multiple instances
// for this type, and raises a Python `Exception` if the check does not pass.
// Because this type differs only in name from the regular Python tuple, it
// would be a good idea in the near future to remove it entirely to allow
// for a pure Python tuple of the same effective structure to be used,
// rendering this type and the capsule below useless.
py_capsule_fn!(
    from mercurial.cext.parsers import make_dirstate_tuple_CAPI
        as make_dirstate_tuple_capi
        signature (
            state: c_char,
            mode: c_int,
            size: c_int,
            mtime: c_int,
        ) -> *mut RawPyObject
);

pub fn make_dirstate_tuple(
    py: Python,
    entry: &DirstateEntry,
) -> PyResult<PyObject> {
    // might be silly to retrieve capsule function in hot loop
    let make = make_dirstate_tuple_capi::retrieve(py)?;

    let &DirstateEntry {
        state,
        mode,
        size,
        mtime,
    } = entry;
    // Explicitly go through u8 first, then cast to platform-specific `c_char`
    // because Into<u8> has a specific implementation while `as c_char` would
    // just do a naive enum cast.
    let state_code: u8 = state.into();

    let maybe_obj = unsafe {
        let ptr = make(state_code as c_char, mode, size, mtime);
        PyObject::from_owned_ptr_opt(py, ptr)
    };
    maybe_obj.ok_or_else(|| PyErr::fetch(py))
}

pub fn extract_dirstate(py: Python, dmap: &PyDict) -> Result<StateMap, PyErr> {
    dmap.items(py)
        .iter()
        .map(|(filename, stats)| {
            let stats = stats.extract::<PySequence>(py)?;
            let state = stats.get_item(py, 0)?.extract::<PyBytes>(py)?;
            let state = EntryState::try_from(state.data(py)[0]).map_err(
                |e: DirstateParseError| {
                    PyErr::new::<exc::ValueError, _>(py, e.to_string())
                },
            )?;
            let mode = stats.get_item(py, 1)?.extract(py)?;
            let size = stats.get_item(py, 2)?.extract(py)?;
            let mtime = stats.get_item(py, 3)?.extract(py)?;
            let filename = filename.extract::<PyBytes>(py)?;
            let filename = filename.data(py);
            Ok((
                HgPathBuf::from(filename.to_owned()),
                DirstateEntry {
                    state,
                    mode,
                    size,
                    mtime,
                },
            ))
        })
        .collect()
}

/// Create the module, with `__package__` given from parent
pub fn init_module(py: Python, package: &str) -> PyResult<PyModule> {
    let dotted_name = &format!("{}.dirstate", package);
    let m = PyModule::new(py, dotted_name)?;

    env_logger::init();

    m.add(py, "__package__", package)?;
    m.add(py, "__doc__", "Dirstate - Rust implementation")?;

    m.add(
        py,
        "FallbackError",
        py.get_type::<exceptions::FallbackError>(),
    )?;
    m.add_class::<Dirs>(py)?;
    m.add_class::<DirstateMap>(py)?;
    m.add(
        py,
        "status",
        py_fn!(
            py,
            status_wrapper(
                dmap: DirstateMap,
                root_dir: PyObject,
                matcher: PyObject,
                ignorefiles: PyList,
                check_exec: bool,
                last_normal_time: i64,
                list_clean: bool,
                list_ignored: bool,
                list_unknown: bool,
                collect_traversed_dirs: bool
            )
        ),
    )?;

    let sys = PyModule::import(py, "sys")?;
    let sys_modules: PyDict = sys.get(py, "modules")?.extract(py)?;
    sys_modules.set_item(py, dotted_name, &m)?;

    Ok(m)
}