comparison rust/hg-core/src/dirstate_tree/dirstate_map.rs @ 47192:1249eb9cc332

dirstate-tree: Refactor DirstateMap::drop_file to be recursive

It should behave the same as before. This will enable the next changeset
to run code on the way "down" (in order to removing newly-empty nodes).

Differential Revision: https://phab.mercurial-scm.org/D10705

47191:b338d831d18c

    /// other fields while the returned borrow is still valid
    fn get_node_mut<'tree>(
        root: &'tree mut ChildNodes<'on_disk>,
        path: &HgPath,
    ) -> Option<&'tree mut Node<'on_disk>> {
        Self::get_node_mut_tracing_ancestors(root, path, |_| {})
    }

    /// Same as `get_node_mut`, and calls `each_ancestor` for each ancestor of
    /// the node.
    ///
    /// Note that `each_ancestor` may be called (with what would be ancestors)
    /// even if it turns out there is no node at `path`.
    fn get_node_mut_tracing_ancestors<'tree>(
        root: &'tree mut ChildNodes<'on_disk>,
        path: &HgPath,
        mut each_ancestor: impl FnMut(&mut Node),
    ) -> Option<&'tree mut Node<'on_disk>> {
        let mut children = root;
        let mut components = path.components();
        let mut component =
            components.next().expect("expected at least one components");
        loop {
            let child = children.get_mut(component)?;
            if let Some(next_component) = components.next() {
                each_ancestor(child);
                component = next_component;
                children = &mut child.children;
            } else {
                return Some(child);
            }

    fn drop_file(
        &mut self,
        filename: &HgPath,
        old_state: EntryState,
    ) -> Result<bool, DirstateMapError> {
        let was_tracked = old_state.is_tracked();
        if let Some(node) = Self::get_node_mut_tracing_ancestors(
            &mut self.root,
            filename,
            |ancestor| {
                if was_tracked {
                    ancestor.tracked_descendants_count -= 1
                }
            },
        ) {
            let had_entry = node.entry.is_some();
            let had_copy_source = node.copy_source.is_some();

            // TODO: this leaves in the tree a "non-file" node. Should we
            // remove the node instead, together with ancestor nodes for
            // directories that become empty?
            node.entry = None;
            node.copy_source = None;

            if had_entry {
                self.nodes_with_entry_count -= 1
            }
            if had_copy_source {
                self.nodes_with_copy_source_count -= 1
            }
            Ok(had_entry)
        } else {
            assert!(!was_tracked);
            Ok(false)
        }
    }

    fn clear_ambiguous_times(&mut self, filenames: Vec<HgPathBuf>, now: i32) {

47192:1249eb9cc332

    /// other fields while the returned borrow is still valid
    fn get_node_mut<'tree>(
        root: &'tree mut ChildNodes<'on_disk>,
        path: &HgPath,
    ) -> Option<&'tree mut Node<'on_disk>> {
        let mut children = root;
        let mut components = path.components();
        let mut component =
            components.next().expect("expected at least one components");
        loop {
            let child = children.get_mut(component)?;
            if let Some(next_component) = components.next() {
                component = next_component;
                children = &mut child.children;
            } else {
                return Some(child);
            }

    fn drop_file(
        &mut self,
        filename: &HgPath,
        old_state: EntryState,
    ) -> Result<bool, DirstateMapError> {
        struct Dropped {
            was_tracked: bool,
            had_entry: bool,
            had_copy_source: bool,
        }
        fn recur(nodes: &mut ChildNodes, path: &HgPath) -> Option<Dropped> {
            let (first_path_component, rest_of_path) =
                path.split_first_component();
            let node = nodes.get_mut(first_path_component)?;
            let dropped;
            if let Some(rest) = rest_of_path {
                dropped = recur(&mut node.children, rest)?;
                if dropped.was_tracked {
                    node.tracked_descendants_count -= 1;
                }
            } else {
                dropped = Dropped {
                    was_tracked: node
                        .entry
                        .as_ref()
                        .map_or(false, |entry| entry.state.is_tracked()),
                    had_entry: node.entry.take().is_some(),
                    had_copy_source: node.copy_source.take().is_some(),
                };
                // TODO: this leaves in the tree a "non-file" node. Should we
                // remove the node instead, together with ancestor nodes for
                // directories that become empty?
            }
            Some(dropped)
        }

        if let Some(dropped) = recur(&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
            }
            Ok(dropped.had_entry)
        } else {
            debug_assert!(!old_state.is_tracked());
            Ok(false)
        }
    }

    fn clear_ambiguous_times(&mut self, filenames: Vec<HgPathBuf>, now: i32) {