--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/rust/hg-cpython/src/dirstate/dirs_multiset.rs	Mon Jul 08 18:01:39 2019 +0200
@@ -0,0 +1,110 @@
+// dirs_multiset.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::dirs_multiset` file provided by the
+//! `hg-core` package.
+
+use std::cell::RefCell;
+
+use cpython::{
+    exc, ObjectProtocol, PyBytes, PyDict, PyErr, PyObject, PyResult,
+    ToPyObject,
+};
+
+use crate::dirstate::extract_dirstate_vec;
+use hg::{DirsIterable, DirsMultiset, DirstateMapError};
+
+py_class!(pub class Dirs |py| {
+    data dirs_map: RefCell<DirsMultiset>;
+
+    // `map` is either a `dict` or a flat iterator (usually a `set`, sometimes
+    // a `list`)
+    def __new__(
+        _cls,
+        map: PyObject,
+        skip: Option<PyObject> = None
+    ) -> PyResult<Self> {
+        let mut skip_state: Option<i8> = None;
+        if let Some(skip) = skip {
+            skip_state = Some(skip.extract::<PyBytes>(py)?.data(py)[0] as i8);
+        }
+        let dirs_map;
+
+        if let Ok(map) = map.cast_as::<PyDict>(py) {
+            let dirstate_vec = extract_dirstate_vec(py, &map)?;
+            dirs_map = DirsMultiset::new(
+                DirsIterable::Dirstate(dirstate_vec),
+                skip_state,
+            )
+        } else {
+            let map: Result<Vec<Vec<u8>>, PyErr> = map
+                .iter(py)?
+                .map(|o| Ok(o?.extract::<PyBytes>(py)?.data(py).to_owned()))
+                .collect();
+            dirs_map = DirsMultiset::new(
+                DirsIterable::Manifest(map?),
+                skip_state,
+            )
+        }
+
+        Self::create_instance(py, RefCell::new(dirs_map))
+    }
+
+    def addpath(&self, path: PyObject) -> PyResult<PyObject> {
+        self.dirs_map(py).borrow_mut().add_path(
+            path.extract::<PyBytes>(py)?.data(py),
+        );
+        Ok(py.None())
+    }
+
+    def delpath(&self, path: PyObject) -> PyResult<PyObject> {
+        self.dirs_map(py).borrow_mut().delete_path(
+            path.extract::<PyBytes>(py)?.data(py),
+        )
+            .and(Ok(py.None()))
+            .or_else(|e| {
+                match e {
+                    DirstateMapError::PathNotFound(_p) => {
+                        Err(PyErr::new::<exc::ValueError, _>(
+                            py,
+                            "expected a value, found none".to_string(),
+                        ))
+                    }
+                    DirstateMapError::EmptyPath => {
+                        Ok(py.None())
+                    }
+                }
+            })
+    }
+
+    // This is really inefficient on top of being ugly, but it's an easy way
+    // of having it work to continue working on the rest of the module
+    // hopefully bypassing Python entirely pretty soon.
+    def __iter__(&self) -> PyResult<PyObject> {
+        let dict = PyDict::new(py);
+
+        for (key, value) in self.dirs_map(py).borrow().iter() {
+            dict.set_item(
+                py,
+                PyBytes::new(py, &key[..]),
+                value.to_py_object(py),
+            )?;
+        }
+
+        let locals = PyDict::new(py);
+        locals.set_item(py, "obj", dict)?;
+
+        py.eval("iter(obj)", None, Some(&locals))
+    }
+
+    def __contains__(&self, item: PyObject) -> PyResult<bool> {
+        Ok(self
+            .dirs_map(py)
+            .borrow()
+            .contains_key(item.extract::<PyBytes>(py)?.data(py).as_ref()))
+    }
+});