comparison rust/hg-core/src/dirstate_tree/dirstate_map.rs @ 47352:9d58e54b5966

dirstate-v2: Drop parent directory cache when removing a dirstate node

The premise of the directory cache is that the dirstate contains child nodes
for every entry that `read_dir` would return. When removing nodes, that may
not be the case anymore so the cache should be invalidated.

Differential Revision: https://phab.mercurial-scm.org/D10829

47351:3b9914b28133

        struct Dropped {
            was_tracked: bool,
            had_entry: bool,
            had_copy_source: bool,
        }
        fn recur<'on_disk>(
            on_disk: &'on_disk [u8],
            nodes: &mut ChildNodes<'on_disk>,
            path: &HgPath,
        ) -> Result<Option<Dropped>, DirstateV2ParseError> {
            let (first_path_component, rest_of_path) =
                path.split_first_component();
            let node = if let Some(node) =
                nodes.make_mut(on_disk)?.get_mut(first_path_component)
            {

            } else {
                return Ok(None);
            };
            let dropped;
            if let Some(rest) = rest_of_path {
                if let Some(d) = recur(on_disk, &mut node.children, rest)? {
                    dropped = d;
                    if dropped.was_tracked {
                        node.tracked_descendants_count -= 1;
                    }
                } else {
                    return Ok(None);
                }
            } else {

                    had_copy_source: node.copy_source.take().is_some(),
                };
            }
            // After recursion, for both leaf (rest_of_path is None) nodes and
            // parent nodes, remove a node if it just became empty.
            if !node.data.has_entry()
                && node.copy_source.is_none()
                && node.children.is_empty()
            {
                nodes.make_mut(on_disk)?.remove(first_path_component);
            }
            Ok(Some(dropped))
        }

        if let Some(dropped) = recur(self.on_disk, &mut self.root, filename)? {
            if dropped.had_entry {
                self.nodes_with_entry_count -= 1
            }
            if dropped.had_copy_source {
                self.nodes_with_copy_source_count -= 1

47352:9d58e54b5966

        struct Dropped {
            was_tracked: bool,
            had_entry: bool,
            had_copy_source: bool,
        }

        /// If this returns `Ok(Some((dropped, removed)))`, then
        ///
        /// * `dropped` is about the leaf node that was at `filename`
        /// * `removed` is whether this particular level of recursion just
        ///   removed a node in `nodes`.
        fn recur<'on_disk>(
            on_disk: &'on_disk [u8],
            nodes: &mut ChildNodes<'on_disk>,
            path: &HgPath,
        ) -> Result<Option<(Dropped, bool)>, DirstateV2ParseError> {
            let (first_path_component, rest_of_path) =
                path.split_first_component();
            let node = if let Some(node) =
                nodes.make_mut(on_disk)?.get_mut(first_path_component)
            {

            } else {
                return Ok(None);
            };
            let dropped;
            if let Some(rest) = rest_of_path {
                if let Some((d, removed)) =
                    recur(on_disk, &mut node.children, rest)?
                {
                    dropped = d;
                    if dropped.was_tracked {
                        node.tracked_descendants_count -= 1;
                    }

                    // Directory caches must be invalidated when removing a
                    // child node
                    if removed {
                        if let NodeData::CachedDirectory { .. } = &node.data {
                            node.data = NodeData::None
                        }
                    }
                } else {
                    return Ok(None);
                }
            } else {

                    had_copy_source: node.copy_source.take().is_some(),
                };
            }
            // After recursion, for both leaf (rest_of_path is None) nodes and
            // parent nodes, remove a node if it just became empty.
            let remove = !node.data.has_entry()
                && node.copy_source.is_none()
                && node.children.is_empty();
            if remove {
                nodes.make_mut(on_disk)?.remove(first_path_component);
            }
            Ok(Some((dropped, remove)))
        }

        if let Some((dropped, _removed)) =
            recur(self.on_disk, &mut self.root, filename)?
        {
            if dropped.had_entry {
                self.nodes_with_entry_count -= 1
            }
            if dropped.had_copy_source {
                self.nodes_with_copy_source_count -= 1