--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/hg-cpython/src/parsers.rs	Wed Jul 10 10:16:28 2019 +0200
@@ -0,0 +1,177 @@
+// parsers.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::parsers` module provided by the
+//! `hg-core` package.
+//!
+//! From Python, this will be seen as `mercurial.rustext.parsers`
+//!
+use cpython::{
+    exc, PyBytes, PyDict, PyErr, PyInt, PyModule, PyResult, PyTuple, Python,
+    PythonObject, ToPyObject,
+};
+use hg::{
+    pack_dirstate, parse_dirstate, CopyVecEntry, DirstateEntry,
+    DirstatePackError, DirstateParents, DirstateParseError,
+};
+use std::collections::HashMap;
+
+use libc::c_char;
+
+use crate::dirstate::{decapsule_make_dirstate_tuple, extract_dirstate_vec};
+
+fn parse_dirstate_wrapper(
+    py: Python,
+    dmap: PyDict,
+    copymap: PyDict,
+    st: PyBytes,
+) -> PyResult<PyTuple> {
+    match parse_dirstate(st.data(py)) {
+        Ok((parents, dirstate_vec, copies)) => {
+            for (filename, entry) in dirstate_vec {
+                dmap.set_item(
+                    py,
+                    PyBytes::new(py, &filename[..]),
+                    decapsule_make_dirstate_tuple(py)?(
+                        entry.state as c_char,
+                        entry.mode,
+                        entry.size,
+                        entry.mtime,
+                    ),
+                )?;
+            }
+            for CopyVecEntry { path, copy_path } in copies {
+                copymap.set_item(
+                    py,
+                    PyBytes::new(py, path),
+                    PyBytes::new(py, copy_path),
+                )?;
+            }
+            Ok((PyBytes::new(py, parents.p1), PyBytes::new(py, parents.p2))
+                .to_py_object(py))
+        }
+        Err(e) => Err(PyErr::new::<exc::ValueError, _>(
+            py,
+            match e {
+                DirstateParseError::TooLittleData => {
+                    "too little data for parents".to_string()
+                }
+                DirstateParseError::Overflow => {
+                    "overflow in dirstate".to_string()
+                }
+                DirstateParseError::CorruptedEntry(e) => e,
+            },
+        )),
+    }
+}
+
+fn pack_dirstate_wrapper(
+    py: Python,
+    dmap: PyDict,
+    copymap: PyDict,
+    pl: PyTuple,
+    now: PyInt,
+) -> PyResult<PyBytes> {
+    let p1 = pl.get_item(py, 0).extract::<PyBytes>(py)?;
+    let p1: &[u8] = p1.data(py);
+    let p2 = pl.get_item(py, 1).extract::<PyBytes>(py)?;
+    let p2: &[u8] = p2.data(py);
+
+    let dirstate_vec = extract_dirstate_vec(py, &dmap)?;
+
+    let copies: Result<HashMap<Vec<u8>, Vec<u8>>, PyErr> = copymap
+        .items(py)
+        .iter()
+        .map(|(key, value)| {
+            Ok((
+                key.extract::<PyBytes>(py)?.data(py).to_owned(),
+                value.extract::<PyBytes>(py)?.data(py).to_owned(),
+            ))
+        })
+        .collect();
+
+    match pack_dirstate(
+        &dirstate_vec,
+        &copies?,
+        DirstateParents { p1, p2 },
+        now.as_object().extract::<i32>(py)?,
+    ) {
+        Ok((packed, new_dirstate_vec)) => {
+            for (
+                filename,
+                DirstateEntry {
+                    state,
+                    mode,
+                    size,
+                    mtime,
+                },
+            ) in new_dirstate_vec
+            {
+                dmap.set_item(
+                    py,
+                    PyBytes::new(py, &filename[..]),
+                    decapsule_make_dirstate_tuple(py)?(
+                        state as c_char,
+                        mode,
+                        size,
+                        mtime,
+                    ),
+                )?;
+            }
+            Ok(PyBytes::new(py, &packed))
+        }
+        Err(error) => Err(PyErr::new::<exc::ValueError, _>(
+            py,
+            match error {
+                DirstatePackError::CorruptedParent => {
+                    "expected a 20-byte hash".to_string()
+                }
+                DirstatePackError::CorruptedEntry(e) => e,
+                DirstatePackError::BadSize(expected, actual) => {
+                    format!("bad dirstate size: {} != {}", actual, expected)
+                }
+            },
+        )),
+    }
+}
+
+/// Create the module, with `__package__` given from parent
+pub fn init_parsers_module(py: Python, package: &str) -> PyResult<PyModule> {
+    let dotted_name = &format!("{}.parsers", package);
+    let m = PyModule::new(py, dotted_name)?;
+
+    m.add(py, "__package__", package)?;
+    m.add(py, "__doc__", "Parsers - Rust implementation")?;
+
+    m.add(
+        py,
+        "parse_dirstate",
+        py_fn!(
+            py,
+            parse_dirstate_wrapper(dmap: PyDict, copymap: PyDict, st: PyBytes)
+        ),
+    )?;
+    m.add(
+        py,
+        "pack_dirstate",
+        py_fn!(
+            py,
+            pack_dirstate_wrapper(
+                dmap: PyDict,
+                copymap: PyDict,
+                pl: PyTuple,
+                now: PyInt
+            )
+        ),
+    )?;
+
+    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)
+}