// dirstate.rs

//

// Copyright 2019 Raphaël Gomès <rgomes@octobus.net>

//

// 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 dirs_multiset;

use crate::dirstate::dirs_multiset::Dirs;

use cpython::{

    exc, PyBytes, PyDict, PyErr, PyModule, PyObject, PyResult, PySequence,

    Python,

};

use hg::{DirstateEntry, DirstateParseError, EntryState, StateMap};

use libc::{c_char, c_int};

#[cfg(feature = "python27")]

use python27_sys::PyCapsule_Import;

#[cfg(feature = "python3")]

use python3_sys::PyCapsule_Import;

use std::convert::TryFrom;

use std::ffi::CStr;

use std::mem::transmute;

/// 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.

type MakeDirstateTupleFn = extern "C" fn(

    state: c_char,

    mode: c_int,

    size: c_int,

    mtime: c_int,

) -> PyObject;

/// This is largely a copy/paste from cindex.rs, pending the merge of a

/// `py_capsule_fn!` macro in the rust-cpython project:

/// https://github.com/dgrunwald/rust-cpython/pull/169

pub fn decapsule_make_dirstate_tuple(

    py: Python,

) -> PyResult<MakeDirstateTupleFn> {

    unsafe {

        let caps_name = CStr::from_bytes_with_nul_unchecked(

            b"mercurial.cext.parsers.make_dirstate_tuple_CAPI\0",

        );

        let from_caps = PyCapsule_Import(caps_name.as_ptr(), 0);

        if from_caps.is_null() {

            return Err(PyErr::fetch(py));

        }

        Ok(transmute(from_caps))

    }

}

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((

                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)?;

    m.add(py, "__package__", package)?;

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

    m.add_class::<Dirs>(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)?;

    Ok(m)

}