annotate rust/hg-cpython/src/dirstate/dirstate_map.rs @ 47123:d8ac62374943

dirstate-tree: Make `DirstateMap` borrow from a bytes buffer

… that has the contents of the `.hg/dirstate` file.
This only applies to the tree-based flavor of `DirstateMap`.

For now only the entire `&[u8]` slice is stored, so this is not useful yet.

Adding a lifetime parameter to the `DirstateMap` struct (in hg-core) makes
Python bindings non-trivial because we keep that struct in a Python object
that has a dynamic lifetime tied to Python’s reference-counting and GC.
As long as we keep the `PyBytes` that owns the borrowed bytes buffer next to
the borrowing struct, the buffer will live long enough for the borrows to stay
valid. However this relationship cannot be expressed in safe Rust code in a
way that would statisfy they borrow-checker. We use `unsafe` code to erase
that lifetime parameter, and encapsulate it in a safe abstraction similar to
the owning-ref crate: https://docs.rs/owning_ref/

Differential Revision: https://phab.mercurial-scm.org/D10557

// dirstate_map.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::dirstate_map` file provided by the
//! `hg-core` package.

use std::cell::{RefCell, RefMut};
use std::convert::TryInto;

use cpython::{
    exc, ObjectProtocol, PyBool, PyBytes, PyClone, PyDict, PyErr, PyList,
    PyObject, PyResult, PySet, PyString, Python, PythonObject, ToPyObject,
    UnsafePyLeaked,
};

use crate::{
    dirstate::copymap::{CopyMap, CopyMapItemsIterator, CopyMapKeysIterator},
    dirstate::non_normal_entries::{
        NonNormalEntries, NonNormalEntriesIterator,
    },
    dirstate::owning::OwningDirstateMap,
    dirstate::{dirs_multiset::Dirs, make_dirstate_tuple},
    parsers::dirstate_parents_to_pytuple,
};
use hg::{
    dirstate::parsers::Timestamp,
    dirstate_tree::dispatch::DirstateMapMethods,
    errors::HgError,
    revlog::Node,
    utils::files::normalize_case,
    utils::hg_path::{HgPath, HgPathBuf},
    DirsMultiset, DirstateEntry, DirstateError,
    DirstateMap as RustDirstateMap, DirstateMapError, DirstateParents,
    EntryState, StateMapIter,
};

// TODO
//     This object needs to share references to multiple members of its Rust
//     inner struct, namely `copy_map`, `dirs` and `all_dirs`.
//     Right now `CopyMap` is done, but it needs to have an explicit reference
//     to `RustDirstateMap` which itself needs to have an encapsulation for
//     every method in `CopyMap` (copymapcopy, etc.).
//     This is ugly and hard to maintain.
//     The same logic applies to `dirs` and `all_dirs`, however the `Dirs`
//     `py_class!` is already implemented and does not mention
//     `RustDirstateMap`, rightfully so.
//     All attributes also have to have a separate refcount data attribute for
//     leaks, with all methods that go along for reference sharing.
py_class!(pub class DirstateMap |py| {
    @shared data inner: Box<dyn DirstateMapMethods + Send>;

    /// Returns a `(dirstate_map, parents)` tuple
    @staticmethod
    def new(use_dirstate_tree: bool, on_disk: PyBytes) -> PyResult<PyObject> {
        let dirstate_error = |_: DirstateError| {
            PyErr::new::<exc::OSError, _>(py, "Dirstate error".to_string())
        };
        let (inner, parents) = if use_dirstate_tree {
            let (map, parents) =
                OwningDirstateMap::new(py, on_disk)
                .map_err(dirstate_error)?;
            (Box::new(map) as _, parents)
        } else {
            let bytes = on_disk.data(py);
            let mut map = RustDirstateMap::default();
            let parents = map.read(bytes).map_err(dirstate_error)?;
            (Box::new(map) as _, parents)
        };
        let map = Self::create_instance(py, inner)?;
        let parents = parents.map(|p| dirstate_parents_to_pytuple(py, &p));
        Ok((map, parents).to_py_object(py).into_object())
    }

    def clear(&self) -> PyResult<PyObject> {
        self.inner(py).borrow_mut().clear();
        Ok(py.None())
    }

    def get(
        &self,
        key: PyObject,
        default: Option<PyObject> = None
    ) -> PyResult<Option<PyObject>> {
        let key = key.extract::<PyBytes>(py)?;
        match self.inner(py).borrow().get(HgPath::new(key.data(py))) {
            Some(entry) => {
                Ok(Some(make_dirstate_tuple(py, entry)?))
            },
            None => Ok(default)
        }
    }

    def addfile(
        &self,
        f: PyObject,
        oldstate: PyObject,
        state: PyObject,
        mode: PyObject,
        size: PyObject,
        mtime: PyObject
    ) -> PyResult<PyObject> {
        self.inner(py).borrow_mut().add_file(
            HgPath::new(f.extract::<PyBytes>(py)?.data(py)),
            oldstate.extract::<PyBytes>(py)?.data(py)[0]
                .try_into()
                .map_err(|e: HgError| {
                    PyErr::new::<exc::ValueError, _>(py, e.to_string())
                })?,
            DirstateEntry {
                state: state.extract::<PyBytes>(py)?.data(py)[0]
                    .try_into()
                    .map_err(|e: HgError| {
                        PyErr::new::<exc::ValueError, _>(py, e.to_string())
                    })?,
                mode: mode.extract(py)?,
                size: size.extract(py)?,
                mtime: mtime.extract(py)?,
            },
        ).and(Ok(py.None())).or_else(|e: DirstateMapError| {
            Err(PyErr::new::<exc::ValueError, _>(py, e.to_string()))
        })
    }

    def removefile(
        &self,
        f: PyObject,
        oldstate: PyObject,
        size: PyObject
    ) -> PyResult<PyObject> {
        self.inner(py).borrow_mut()
            .remove_file(
                HgPath::new(f.extract::<PyBytes>(py)?.data(py)),
                oldstate.extract::<PyBytes>(py)?.data(py)[0]
                    .try_into()
                    .map_err(|e: HgError| {
                        PyErr::new::<exc::ValueError, _>(py, e.to_string())
                    })?,
                size.extract(py)?,
            )
            .or_else(|_| {
                Err(PyErr::new::<exc::OSError, _>(
                    py,
                    "Dirstate error".to_string(),
                ))
            })?;
        Ok(py.None())
    }

    def dropfile(
        &self,
        f: PyObject,
        oldstate: PyObject
    ) -> PyResult<PyBool> {
        self.inner(py).borrow_mut()
            .drop_file(
                HgPath::new(f.extract::<PyBytes>(py)?.data(py)),
                oldstate.extract::<PyBytes>(py)?.data(py)[0]
                    .try_into()
                    .map_err(|e: HgError| {
                        PyErr::new::<exc::ValueError, _>(py, e.to_string())
                    })?,
            )
            .and_then(|b| Ok(b.to_py_object(py)))
            .or_else(|e| {
                Err(PyErr::new::<exc::OSError, _>(
                    py,
                    format!("Dirstate error: {}", e.to_string()),
                ))
            })
    }

    def clearambiguoustimes(
        &self,
        files: PyObject,
        now: PyObject
    ) -> PyResult<PyObject> {
        let files: PyResult<Vec<HgPathBuf>> = files
            .iter(py)?
            .map(|filename| {
                Ok(HgPathBuf::from_bytes(
                    filename?.extract::<PyBytes>(py)?.data(py),
                ))
            })
            .collect();
        self.inner(py).borrow_mut()
            .clear_ambiguous_times(files?, now.extract(py)?);
        Ok(py.None())
    }

    def other_parent_entries(&self) -> PyResult<PyObject> {
        let mut inner_shared = self.inner(py).borrow_mut();
        let set = PySet::empty(py)?;
        for path in inner_shared.iter_other_parent_paths() {
            set.add(py, PyBytes::new(py, path.as_bytes()))?;
        }
        Ok(set.into_object())
    }

    def non_normal_entries(&self) -> PyResult<NonNormalEntries> {
        NonNormalEntries::from_inner(py, self.clone_ref(py))
    }

    def non_normal_entries_contains(&self, key: PyObject) -> PyResult<bool> {
        let key = key.extract::<PyBytes>(py)?;
        Ok(self
            .inner(py)
            .borrow_mut()
            .non_normal_entries_contains(HgPath::new(key.data(py))))
    }

    def non_normal_entries_display(&self) -> PyResult<PyString> {
        Ok(
            PyString::new(
                py,
                &format!(
                    "NonNormalEntries: {}",
                    hg::utils::join_display(
                        self
                            .inner(py)
                            .borrow_mut()
                            .iter_non_normal_paths(),
                        ", "
                    )
                )
            )
        )
    }

    def non_normal_entries_remove(&self, key: PyObject) -> PyResult<PyObject> {
        let key = key.extract::<PyBytes>(py)?;
        self
            .inner(py)
            .borrow_mut()
            .non_normal_entries_remove(HgPath::new(key.data(py)));
        Ok(py.None())
    }

    def non_normal_or_other_parent_paths(&self) -> PyResult<PyList> {
        let mut inner = self.inner(py).borrow_mut();

        let ret = PyList::new(py, &[]);
        for filename in inner.non_normal_or_other_parent_paths() {
            let as_pystring = PyBytes::new(py, filename.as_bytes());
            ret.append(py, as_pystring.into_object());
        }
        Ok(ret)
    }

    def non_normal_entries_iter(&self) -> PyResult<NonNormalEntriesIterator> {
        // Make sure the sets are defined before we no longer have a mutable
        // reference to the dmap.
        self.inner(py)
            .borrow_mut()
            .set_non_normal_other_parent_entries(false);

        let leaked_ref = self.inner(py).leak_immutable();

        NonNormalEntriesIterator::from_inner(py, unsafe {
            leaked_ref.map(py, |o| {
                o.iter_non_normal_paths_panic()
            })
        })
    }

    def hastrackeddir(&self, d: PyObject) -> PyResult<PyBool> {
        let d = d.extract::<PyBytes>(py)?;
        Ok(self.inner(py).borrow_mut()
            .has_tracked_dir(HgPath::new(d.data(py)))
            .map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?
            .to_py_object(py))
    }

    def hasdir(&self, d: PyObject) -> PyResult<PyBool> {
        let d = d.extract::<PyBytes>(py)?;
        Ok(self.inner(py).borrow_mut()
            .has_dir(HgPath::new(d.data(py)))
            .map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?
            .to_py_object(py))
    }

    def write(
        &self,
        p1: PyObject,
        p2: PyObject,
        now: PyObject
    ) -> PyResult<PyBytes> {
        let now = Timestamp(now.extract(py)?);
        let parents = DirstateParents {
            p1: extract_node_id(py, &p1)?,
            p2: extract_node_id(py, &p2)?,
        };

        match self.inner(py).borrow_mut().pack(parents, now) {
            Ok(packed) => Ok(PyBytes::new(py, &packed)),
            Err(_) => Err(PyErr::new::<exc::OSError, _>(
                py,
                "Dirstate error".to_string(),
            )),
        }
    }

    def filefoldmapasdict(&self) -> PyResult<PyDict> {
        let dict = PyDict::new(py);
        for (path, entry) in self.inner(py).borrow_mut().iter() {
            if entry.state != EntryState::Removed {
                let key = normalize_case(path);
                let value = path;
                dict.set_item(
                    py,
                    PyBytes::new(py, key.as_bytes()).into_object(),
                    PyBytes::new(py, value.as_bytes()).into_object(),
                )?;
            }
        }
        Ok(dict)
    }

    def __len__(&self) -> PyResult<usize> {
        Ok(self.inner(py).borrow().len())
    }

    def __contains__(&self, key: PyObject) -> PyResult<bool> {
        let key = key.extract::<PyBytes>(py)?;
        Ok(self.inner(py).borrow().contains_key(HgPath::new(key.data(py))))
    }

    def __getitem__(&self, key: PyObject) -> PyResult<PyObject> {
        let key = key.extract::<PyBytes>(py)?;
        let key = HgPath::new(key.data(py));
        match self.inner(py).borrow().get(key) {
            Some(entry) => {
                Ok(make_dirstate_tuple(py, entry)?)
            },
            None => Err(PyErr::new::<exc::KeyError, _>(
                py,
                String::from_utf8_lossy(key.as_bytes()),
            )),
        }
    }

    def keys(&self) -> PyResult<DirstateMapKeysIterator> {
        let leaked_ref = self.inner(py).leak_immutable();
        DirstateMapKeysIterator::from_inner(
            py,
            unsafe { leaked_ref.map(py, |o| o.iter()) },
        )
    }

    def items(&self) -> PyResult<DirstateMapItemsIterator> {
        let leaked_ref = self.inner(py).leak_immutable();
        DirstateMapItemsIterator::from_inner(
            py,
            unsafe { leaked_ref.map(py, |o| o.iter()) },
        )
    }

    def __iter__(&self) -> PyResult<DirstateMapKeysIterator> {
        let leaked_ref = self.inner(py).leak_immutable();
        DirstateMapKeysIterator::from_inner(
            py,
            unsafe { leaked_ref.map(py, |o| o.iter()) },
        )
    }

    def getdirs(&self) -> PyResult<Dirs> {
        // TODO don't copy, share the reference
        self.inner(py).borrow_mut().set_dirs()
            .map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?;
        Dirs::from_inner(
            py,
            DirsMultiset::from_dirstate(
                self.inner(py).borrow().iter(),
                Some(EntryState::Removed),
            )
            .map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?,
        )
    }
    def getalldirs(&self) -> PyResult<Dirs> {
        // TODO don't copy, share the reference
        self.inner(py).borrow_mut().set_all_dirs()
            .map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?;
        Dirs::from_inner(
            py,
            DirsMultiset::from_dirstate(
                self.inner(py).borrow().iter(),
                None,
            ).map_err(|e| {
                PyErr::new::<exc::ValueError, _>(py, e.to_string())
            })?,
        )
    }

    // TODO all copymap* methods, see docstring above
    def copymapcopy(&self) -> PyResult<PyDict> {
        let dict = PyDict::new(py);
        for (key, value) in self.inner(py).borrow().copy_map_iter() {
            dict.set_item(
                py,
                PyBytes::new(py, key.as_bytes()),
                PyBytes::new(py, value.as_bytes()),
            )?;
        }
        Ok(dict)
    }

    def copymapgetitem(&self, key: PyObject) -> PyResult<PyBytes> {
        let key = key.extract::<PyBytes>(py)?;
        match self.inner(py).borrow().copy_map_get(HgPath::new(key.data(py))) {
            Some(copy) => Ok(PyBytes::new(py, copy.as_bytes())),
            None => Err(PyErr::new::<exc::KeyError, _>(
                py,
                String::from_utf8_lossy(key.data(py)),
            )),
        }
    }
    def copymap(&self) -> PyResult<CopyMap> {
        CopyMap::from_inner(py, self.clone_ref(py))
    }

    def copymaplen(&self) -> PyResult<usize> {
        Ok(self.inner(py).borrow().copy_map_len())
    }
    def copymapcontains(&self, key: PyObject) -> PyResult<bool> {
        let key = key.extract::<PyBytes>(py)?;
        Ok(self
            .inner(py)
            .borrow()
            .copy_map_contains_key(HgPath::new(key.data(py))))
    }
    def copymapget(
        &self,
        key: PyObject,
        default: Option<PyObject>
    ) -> PyResult<Option<PyObject>> {
        let key = key.extract::<PyBytes>(py)?;
        match self
            .inner(py)
            .borrow()
            .copy_map_get(HgPath::new(key.data(py)))
        {
            Some(copy) => Ok(Some(
                PyBytes::new(py, copy.as_bytes()).into_object(),
            )),
            None => Ok(default),
        }
    }
    def copymapsetitem(
        &self,
        key: PyObject,
        value: PyObject
    ) -> PyResult<PyObject> {
        let key = key.extract::<PyBytes>(py)?;
        let value = value.extract::<PyBytes>(py)?;
        self.inner(py).borrow_mut().copy_map_insert(
            HgPathBuf::from_bytes(key.data(py)),
            HgPathBuf::from_bytes(value.data(py)),
        );
        Ok(py.None())
    }
    def copymappop(
        &self,
        key: PyObject,
        default: Option<PyObject>
    ) -> PyResult<Option<PyObject>> {
        let key = key.extract::<PyBytes>(py)?;
        match self
            .inner(py)
            .borrow_mut()
            .copy_map_remove(HgPath::new(key.data(py)))
        {
            Some(_) => Ok(None),
            None => Ok(default),
        }
    }

    def copymapiter(&self) -> PyResult<CopyMapKeysIterator> {
        let leaked_ref = self.inner(py).leak_immutable();
        CopyMapKeysIterator::from_inner(
            py,
            unsafe { leaked_ref.map(py, |o| o.copy_map_iter()) },
        )
    }

    def copymapitemsiter(&self) -> PyResult<CopyMapItemsIterator> {
        let leaked_ref = self.inner(py).leak_immutable();
        CopyMapItemsIterator::from_inner(
            py,
            unsafe { leaked_ref.map(py, |o| o.copy_map_iter()) },
        )
    }

});

impl DirstateMap {
    pub fn get_inner_mut<'a>(
        &'a self,
        py: Python<'a>,
    ) -> RefMut<'a, Box<dyn DirstateMapMethods + Send>> {
        self.inner(py).borrow_mut()
    }
    fn translate_key(
        py: Python,
        res: (&HgPathBuf, &DirstateEntry),
    ) -> PyResult<Option<PyBytes>> {
        Ok(Some(PyBytes::new(py, res.0.as_bytes())))
    }
    fn translate_key_value(
        py: Python,
        res: (&HgPathBuf, &DirstateEntry),
    ) -> PyResult<Option<(PyBytes, PyObject)>> {
        let (f, entry) = res;
        Ok(Some((
            PyBytes::new(py, f.as_bytes()),
            make_dirstate_tuple(py, &entry)?,
        )))
    }
}

py_shared_iterator!(
    DirstateMapKeysIterator,
    UnsafePyLeaked<StateMapIter<'static>>,
    DirstateMap::translate_key,
    Option<PyBytes>
);

py_shared_iterator!(
    DirstateMapItemsIterator,
    UnsafePyLeaked<StateMapIter<'static>>,
    DirstateMap::translate_key_value,
    Option<(PyBytes, PyObject)>
);

fn extract_node_id(py: Python, obj: &PyObject) -> PyResult<Node> {
    let bytes = obj.extract::<PyBytes>(py)?;
    match bytes.data(py).try_into() {
        Ok(s) => Ok(s),
        Err(e) => Err(PyErr::new::<exc::ValueError, _>(py, e.to_string())),
    }
}