comparison rust/hg-cpython/src/dirstate/dirstate_map.rs @ 47682:78f7f0d490ee

dirstate-v2: Move fixed-size tree metadata into the docket file

Before this changeset, the dirstate-v2 data file contained not only nodes
and paths that may be reused when appending to an existing file,
but also some fixed-size metadata that applies to the entire tree
and was added at the end of the data file for every append.

This moves that metadata into the docket file, so that repeated "append"
operations without meaningful changes don’t actually need to grow any file.

Differential Revision: https://phab.mercurial-scm.org/D11098

47681:d94118365ec5

    /// Returns a DirstateMap
    @staticmethod
    def new_v2(
        on_disk: PyBytes,
        data_size: usize,
    ) -> PyResult<PyObject> {
        let dirstate_error = |e: DirstateError| {
            PyErr::new::<exc::OSError, _>(py, format!("Dirstate error: {:?}", e))
        };
        let inner = OwningDirstateMap::new_v2(py, on_disk, data_size)
                .map_err(dirstate_error)?;
        let map = Self::create_instance(py, Box::new(inner))?;
        Ok(map.into_object())
    }

    def clear(&self) -> PyResult<PyObject> {

        let now = Timestamp(now.extract(py)?);

        let mut inner = self.inner(py).borrow_mut();
        let result = inner.pack_v2(now, can_append);
        match result {
            Ok((packed, append)) => {
                let packed = PyBytes::new(py, &packed);
                Ok((packed, append).to_py_object(py).into_object())
            },
            Err(_) => Err(PyErr::new::<exc::OSError, _>(
                py,
                "Dirstate error".to_string(),
            )),

47682:78f7f0d490ee

    /// Returns a DirstateMap
    @staticmethod
    def new_v2(
        on_disk: PyBytes,
        data_size: usize,
        tree_metadata: PyBytes,
    ) -> PyResult<PyObject> {
        let dirstate_error = |e: DirstateError| {
            PyErr::new::<exc::OSError, _>(py, format!("Dirstate error: {:?}", e))
        };
        let inner = OwningDirstateMap::new_v2(
            py, on_disk, data_size, tree_metadata,
        ).map_err(dirstate_error)?;
        let map = Self::create_instance(py, Box::new(inner))?;
        Ok(map.into_object())
    }

    def clear(&self) -> PyResult<PyObject> {

        let now = Timestamp(now.extract(py)?);

        let mut inner = self.inner(py).borrow_mut();
        let result = inner.pack_v2(now, can_append);
        match result {
            Ok((packed, tree_metadata, append)) => {
                let packed = PyBytes::new(py, &packed);
                let tree_metadata = PyBytes::new(py, &tree_metadata);
                let tuple = (packed, tree_metadata, append);
                Ok(tuple.to_py_object(py).into_object())
            },
            Err(_) => Err(PyErr::new::<exc::OSError, _>(
                py,
                "Dirstate error".to_string(),
            )),