WIP: Move sum_tree module into gpui so we can use it in List
This commit is contained in:
Nathan Sobo
parent
2507f9b4d4
commit
c3dda14490
16 changed files with 190 additions and 138 deletions
665
gpui/src/sum_tree/cursor.rs
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665
gpui/src/sum_tree/cursor.rs
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@ -0,0 +1,665 @@
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use super::*;
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use arrayvec::ArrayVec;
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use std::{cmp::Ordering, sync::Arc};
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#[derive(Clone)]
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struct StackEntry<'a, T: Item, S, U> {
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tree: &'a SumTree<T>,
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index: usize,
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seek_dimension: S,
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sum_dimension: U,
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}
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#[derive(Clone)]
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pub struct Cursor<'a, T: Item, S, U> {
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tree: &'a SumTree<T>,
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stack: ArrayVec<StackEntry<'a, T, S, U>, 16>,
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seek_dimension: S,
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sum_dimension: U,
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did_seek: bool,
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at_end: bool,
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}
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impl<'a, T, S, U> Cursor<'a, T, S, U>
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where
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T: Item,
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S: Dimension<'a, T::Summary>,
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U: Dimension<'a, T::Summary>,
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{
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pub fn new(tree: &'a SumTree<T>) -> Self {
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Self {
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tree,
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stack: ArrayVec::new(),
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seek_dimension: S::default(),
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sum_dimension: U::default(),
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did_seek: false,
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at_end: false,
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}
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}
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fn reset(&mut self) {
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self.did_seek = false;
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self.at_end = false;
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self.stack.truncate(0);
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self.seek_dimension = S::default();
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self.sum_dimension = U::default();
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}
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pub fn seek_start(&self) -> &S {
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&self.seek_dimension
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}
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pub fn seek_end(&self, cx: &<T::Summary as Summary>::Context) -> S {
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if let Some(item_summary) = self.item_summary() {
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let mut end = self.seek_start().clone();
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end.add_summary(item_summary, cx);
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end
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} else {
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self.seek_start().clone()
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}
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}
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pub fn sum_start(&self) -> &U {
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&self.sum_dimension
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}
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pub fn sum_end(&self, cx: &<T::Summary as Summary>::Context) -> U {
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if let Some(item_summary) = self.item_summary() {
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let mut end = self.sum_start().clone();
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end.add_summary(item_summary, cx);
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end
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} else {
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self.sum_start().clone()
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}
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}
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pub fn item(&self) -> Option<&'a T> {
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assert!(self.did_seek, "Must seek before calling this method");
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if let Some(entry) = self.stack.last() {
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match *entry.tree.0 {
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Node::Leaf { ref items, .. } => {
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if entry.index == items.len() {
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None
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} else {
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Some(&items[entry.index])
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}
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}
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_ => unreachable!(),
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}
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} else {
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None
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}
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}
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pub fn item_summary(&self) -> Option<&'a T::Summary> {
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assert!(self.did_seek, "Must seek before calling this method");
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if let Some(entry) = self.stack.last() {
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match *entry.tree.0 {
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Node::Leaf {
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ref item_summaries, ..
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} => {
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if entry.index == item_summaries.len() {
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None
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} else {
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Some(&item_summaries[entry.index])
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}
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}
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_ => unreachable!(),
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}
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} else {
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None
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}
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}
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pub fn prev_item(&self) -> Option<&'a T> {
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assert!(self.did_seek, "Must seek before calling this method");
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if let Some(entry) = self.stack.last() {
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if entry.index == 0 {
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if let Some(prev_leaf) = self.prev_leaf() {
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Some(prev_leaf.0.items().last().unwrap())
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} else {
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None
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}
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} else {
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match *entry.tree.0 {
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Node::Leaf { ref items, .. } => Some(&items[entry.index - 1]),
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_ => unreachable!(),
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}
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}
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} else if self.at_end {
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self.tree.last()
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} else {
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None
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}
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}
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fn prev_leaf(&self) -> Option<&'a SumTree<T>> {
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for entry in self.stack.iter().rev().skip(1) {
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if entry.index != 0 {
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match *entry.tree.0 {
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Node::Internal {
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ref child_trees, ..
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} => return Some(child_trees[entry.index - 1].rightmost_leaf()),
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Node::Leaf { .. } => unreachable!(),
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};
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}
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}
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None
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}
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#[allow(unused)]
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pub fn prev(&mut self, cx: &<T::Summary as Summary>::Context) {
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assert!(self.did_seek, "Must seek before calling this method");
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if self.at_end {
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self.seek_dimension = S::default();
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self.sum_dimension = U::default();
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self.descend_to_last_item(self.tree, cx);
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self.at_end = false;
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} else {
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while let Some(entry) = self.stack.pop() {
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if entry.index > 0 {
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let new_index = entry.index - 1;
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if let Some(StackEntry {
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seek_dimension,
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sum_dimension,
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..
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}) = self.stack.last()
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{
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self.seek_dimension = seek_dimension.clone();
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self.sum_dimension = sum_dimension.clone();
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} else {
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self.seek_dimension = S::default();
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self.sum_dimension = U::default();
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}
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match entry.tree.0.as_ref() {
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Node::Internal {
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child_trees,
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child_summaries,
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..
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} => {
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for summary in &child_summaries[0..new_index] {
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self.seek_dimension.add_summary(summary, cx);
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self.sum_dimension.add_summary(summary, cx);
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}
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self.stack.push(StackEntry {
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tree: entry.tree,
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index: new_index,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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self.descend_to_last_item(&child_trees[new_index], cx);
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}
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Node::Leaf { item_summaries, .. } => {
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for item_summary in &item_summaries[0..new_index] {
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self.seek_dimension.add_summary(item_summary, cx);
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self.sum_dimension.add_summary(item_summary, cx);
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}
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self.stack.push(StackEntry {
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tree: entry.tree,
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index: new_index,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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}
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}
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break;
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}
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}
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}
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}
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pub fn next(&mut self, cx: &<T::Summary as Summary>::Context) {
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self.next_internal(|_| true, cx)
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}
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fn next_internal<F>(&mut self, filter_node: F, cx: &<T::Summary as Summary>::Context)
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where
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F: Fn(&T::Summary) -> bool,
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{
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let mut descend = false;
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if self.stack.is_empty() && !self.at_end {
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self.stack.push(StackEntry {
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tree: self.tree,
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index: 0,
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seek_dimension: S::default(),
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sum_dimension: U::default(),
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});
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descend = true;
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self.did_seek = true;
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}
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while self.stack.len() > 0 {
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let new_subtree = {
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let entry = self.stack.last_mut().unwrap();
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match entry.tree.0.as_ref() {
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Node::Internal {
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child_trees,
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child_summaries,
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..
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} => {
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if !descend {
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entry.seek_dimension = self.seek_dimension.clone();
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entry.sum_dimension = self.sum_dimension.clone();
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entry.index += 1;
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}
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while entry.index < child_summaries.len() {
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let next_summary = &child_summaries[entry.index];
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if filter_node(next_summary) {
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break;
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} else {
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self.seek_dimension.add_summary(next_summary, cx);
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self.sum_dimension.add_summary(next_summary, cx);
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}
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entry.index += 1;
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}
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child_trees.get(entry.index)
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}
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Node::Leaf { item_summaries, .. } => {
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if !descend {
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let item_summary = &item_summaries[entry.index];
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self.seek_dimension.add_summary(item_summary, cx);
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entry.seek_dimension.add_summary(item_summary, cx);
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self.sum_dimension.add_summary(item_summary, cx);
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entry.sum_dimension.add_summary(item_summary, cx);
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entry.index += 1;
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}
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loop {
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if let Some(next_item_summary) = item_summaries.get(entry.index) {
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if filter_node(next_item_summary) {
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return;
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} else {
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self.seek_dimension.add_summary(next_item_summary, cx);
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entry.seek_dimension.add_summary(next_item_summary, cx);
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self.sum_dimension.add_summary(next_item_summary, cx);
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entry.sum_dimension.add_summary(next_item_summary, cx);
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entry.index += 1;
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}
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} else {
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break None;
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}
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}
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}
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}
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};
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if let Some(subtree) = new_subtree {
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descend = true;
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self.stack.push(StackEntry {
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tree: subtree,
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index: 0,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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} else {
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descend = false;
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self.stack.pop();
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}
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}
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self.at_end = self.stack.is_empty();
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debug_assert!(self.stack.is_empty() || self.stack.last().unwrap().tree.0.is_leaf());
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}
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fn descend_to_last_item(
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&mut self,
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mut subtree: &'a SumTree<T>,
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cx: &<T::Summary as Summary>::Context,
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) {
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self.did_seek = true;
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loop {
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match subtree.0.as_ref() {
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Node::Internal {
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child_trees,
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child_summaries,
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..
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} => {
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for summary in &child_summaries[0..child_summaries.len() - 1] {
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self.seek_dimension.add_summary(summary, cx);
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self.sum_dimension.add_summary(summary, cx);
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}
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self.stack.push(StackEntry {
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tree: subtree,
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index: child_trees.len() - 1,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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subtree = child_trees.last().unwrap();
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}
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Node::Leaf { item_summaries, .. } => {
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let last_index = item_summaries.len().saturating_sub(1);
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for item_summary in &item_summaries[0..last_index] {
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self.seek_dimension.add_summary(item_summary, cx);
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self.sum_dimension.add_summary(item_summary, cx);
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}
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self.stack.push(StackEntry {
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tree: subtree,
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index: last_index,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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break;
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}
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}
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}
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}
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}
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impl<'a, T, S, U> Cursor<'a, T, S, U>
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where
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T: Item,
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S: SeekDimension<'a, T::Summary>,
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U: Dimension<'a, T::Summary>,
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{
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pub fn seek(&mut self, pos: &S, bias: Bias, cx: &<T::Summary as Summary>::Context) -> bool {
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self.reset();
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self.seek_internal::<()>(Some(pos), bias, &mut SeekAggregate::None, cx)
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}
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pub fn seek_forward(
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&mut self,
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pos: &S,
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bias: Bias,
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cx: &<T::Summary as Summary>::Context,
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) -> bool {
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self.seek_internal::<()>(Some(pos), bias, &mut SeekAggregate::None, cx)
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}
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pub fn slice(
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&mut self,
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end: &S,
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bias: Bias,
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cx: &<T::Summary as Summary>::Context,
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) -> SumTree<T> {
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let mut slice = SeekAggregate::Slice(SumTree::new());
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self.seek_internal::<()>(Some(end), bias, &mut slice, cx);
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if let SeekAggregate::Slice(slice) = slice {
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slice
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} else {
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unreachable!()
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}
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}
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pub fn suffix(&mut self, cx: &<T::Summary as Summary>::Context) -> SumTree<T> {
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let mut slice = SeekAggregate::Slice(SumTree::new());
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self.seek_internal::<()>(None, Bias::Right, &mut slice, cx);
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if let SeekAggregate::Slice(slice) = slice {
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slice
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} else {
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unreachable!()
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}
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}
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pub fn summary<D>(&mut self, end: &S, bias: Bias, cx: &<T::Summary as Summary>::Context) -> D
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where
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D: Dimension<'a, T::Summary>,
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{
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let mut summary = SeekAggregate::Summary(D::default());
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self.seek_internal(Some(end), bias, &mut summary, cx);
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if let SeekAggregate::Summary(summary) = summary {
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summary
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} else {
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unreachable!()
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}
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}
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fn seek_internal<D>(
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&mut self,
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target: Option<&S>,
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bias: Bias,
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aggregate: &mut SeekAggregate<T, D>,
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cx: &<T::Summary as Summary>::Context,
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) -> bool
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where
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D: Dimension<'a, T::Summary>,
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{
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if let Some(target) = target {
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debug_assert!(
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target.cmp(&self.seek_dimension, cx) >= Ordering::Equal,
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"cannot seek backward from {:?} to {:?}",
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self.seek_dimension,
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target
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);
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}
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if !self.did_seek {
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self.did_seek = true;
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self.stack.push(StackEntry {
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tree: self.tree,
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index: 0,
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seek_dimension: Default::default(),
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sum_dimension: Default::default(),
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});
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}
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let mut ascending = false;
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'outer: while let Some(entry) = self.stack.last_mut() {
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match *entry.tree.0 {
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Node::Internal {
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ref child_summaries,
|
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ref child_trees,
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..
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} => {
|
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if ascending {
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entry.index += 1;
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}
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for (child_tree, child_summary) in child_trees[entry.index..]
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.iter()
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.zip(&child_summaries[entry.index..])
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{
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let mut child_end = self.seek_dimension.clone();
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child_end.add_summary(&child_summary, cx);
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let comparison =
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target.map_or(Ordering::Greater, |t| t.cmp(&child_end, cx));
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if comparison == Ordering::Greater
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|| (comparison == Ordering::Equal && bias == Bias::Right)
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{
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self.seek_dimension = child_end;
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self.sum_dimension.add_summary(child_summary, cx);
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match aggregate {
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SeekAggregate::None => {}
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SeekAggregate::Slice(slice) => {
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slice.push_tree(child_tree.clone(), cx);
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}
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SeekAggregate::Summary(summary) => {
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summary.add_summary(child_summary, cx);
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}
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}
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entry.index += 1;
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entry.seek_dimension = self.seek_dimension.clone();
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entry.sum_dimension = self.sum_dimension.clone();
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} else {
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self.stack.push(StackEntry {
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tree: child_tree,
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index: 0,
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seek_dimension: self.seek_dimension.clone(),
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sum_dimension: self.sum_dimension.clone(),
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});
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ascending = false;
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continue 'outer;
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}
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}
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}
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Node::Leaf {
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ref items,
|
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ref item_summaries,
|
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..
|
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} => {
|
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let mut slice_items = ArrayVec::<T, { 2 * TREE_BASE }>::new();
|
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let mut slice_item_summaries = ArrayVec::<T::Summary, { 2 * TREE_BASE }>::new();
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let mut slice_items_summary = match aggregate {
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SeekAggregate::Slice(_) => Some(T::Summary::default()),
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||||
_ => None,
|
||||
};
|
||||
|
||||
for (item, item_summary) in items[entry.index..]
|
||||
.iter()
|
||||
.zip(&item_summaries[entry.index..])
|
||||
{
|
||||
let mut child_end = self.seek_dimension.clone();
|
||||
child_end.add_summary(item_summary, cx);
|
||||
|
||||
let comparison =
|
||||
target.map_or(Ordering::Greater, |t| t.cmp(&child_end, cx));
|
||||
if comparison == Ordering::Greater
|
||||
|| (comparison == Ordering::Equal && bias == Bias::Right)
|
||||
{
|
||||
self.seek_dimension = child_end;
|
||||
self.sum_dimension.add_summary(item_summary, cx);
|
||||
match aggregate {
|
||||
SeekAggregate::None => {}
|
||||
SeekAggregate::Slice(_) => {
|
||||
slice_items.push(item.clone());
|
||||
slice_item_summaries.push(item_summary.clone());
|
||||
slice_items_summary
|
||||
.as_mut()
|
||||
.unwrap()
|
||||
.add_summary(item_summary, cx);
|
||||
}
|
||||
SeekAggregate::Summary(summary) => {
|
||||
summary.add_summary(item_summary, cx);
|
||||
}
|
||||
}
|
||||
entry.index += 1;
|
||||
} else {
|
||||
if let SeekAggregate::Slice(slice) = aggregate {
|
||||
slice.push_tree(
|
||||
SumTree(Arc::new(Node::Leaf {
|
||||
summary: slice_items_summary.unwrap(),
|
||||
items: slice_items,
|
||||
item_summaries: slice_item_summaries,
|
||||
})),
|
||||
cx,
|
||||
);
|
||||
}
|
||||
break 'outer;
|
||||
}
|
||||
}
|
||||
|
||||
if let SeekAggregate::Slice(slice) = aggregate {
|
||||
if !slice_items.is_empty() {
|
||||
slice.push_tree(
|
||||
SumTree(Arc::new(Node::Leaf {
|
||||
summary: slice_items_summary.unwrap(),
|
||||
items: slice_items,
|
||||
item_summaries: slice_item_summaries,
|
||||
})),
|
||||
cx,
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
self.stack.pop();
|
||||
ascending = true;
|
||||
}
|
||||
|
||||
self.at_end = self.stack.is_empty();
|
||||
debug_assert!(self.stack.is_empty() || self.stack.last().unwrap().tree.0.is_leaf());
|
||||
|
||||
let mut end = self.seek_dimension.clone();
|
||||
if bias == Bias::Left {
|
||||
if let Some(summary) = self.item_summary() {
|
||||
end.add_summary(summary, cx);
|
||||
}
|
||||
}
|
||||
|
||||
target.map_or(false, |t| t.cmp(&end, cx) == Ordering::Equal)
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, T, S, Seek, Sum> Iterator for Cursor<'a, T, Seek, Sum>
|
||||
where
|
||||
T: Item<Summary = S>,
|
||||
S: Summary<Context = ()>,
|
||||
Seek: Dimension<'a, T::Summary>,
|
||||
Sum: Dimension<'a, T::Summary>,
|
||||
{
|
||||
type Item = &'a T;
|
||||
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
if !self.did_seek {
|
||||
self.next(&());
|
||||
}
|
||||
|
||||
if let Some(item) = self.item() {
|
||||
self.next(&());
|
||||
Some(item)
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
pub struct FilterCursor<'a, F: Fn(&T::Summary) -> bool, T: Item, U> {
|
||||
cursor: Cursor<'a, T, (), U>,
|
||||
filter_node: F,
|
||||
}
|
||||
|
||||
impl<'a, F, T, U> FilterCursor<'a, F, T, U>
|
||||
where
|
||||
F: Fn(&T::Summary) -> bool,
|
||||
T: Item,
|
||||
U: Dimension<'a, T::Summary>,
|
||||
{
|
||||
pub fn new(
|
||||
tree: &'a SumTree<T>,
|
||||
filter_node: F,
|
||||
cx: &<T::Summary as Summary>::Context,
|
||||
) -> Self {
|
||||
let mut cursor = tree.cursor::<(), U>();
|
||||
cursor.next_internal(&filter_node, cx);
|
||||
Self {
|
||||
cursor,
|
||||
filter_node,
|
||||
}
|
||||
}
|
||||
|
||||
pub fn start(&self) -> &U {
|
||||
self.cursor.sum_start()
|
||||
}
|
||||
|
||||
pub fn item(&self) -> Option<&'a T> {
|
||||
self.cursor.item()
|
||||
}
|
||||
|
||||
pub fn next(&mut self, cx: &<T::Summary as Summary>::Context) {
|
||||
self.cursor.next_internal(&self.filter_node, cx);
|
||||
}
|
||||
}
|
||||
|
||||
impl<'a, F, T, S, U> Iterator for FilterCursor<'a, F, T, U>
|
||||
where
|
||||
F: Fn(&T::Summary) -> bool,
|
||||
T: Item<Summary = S>,
|
||||
S: Summary<Context = ()>,
|
||||
U: Dimension<'a, T::Summary>,
|
||||
{
|
||||
type Item = &'a T;
|
||||
|
||||
fn next(&mut self) -> Option<Self::Item> {
|
||||
if let Some(item) = self.item() {
|
||||
self.cursor.next_internal(&self.filter_node, &());
|
||||
Some(item)
|
||||
} else {
|
||||
None
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
enum SeekAggregate<T: Item, D> {
|
||||
None,
|
||||
Slice(SumTree<T>),
|
||||
Summary(D),
|
||||
}
|
||||
Loading…
Add table
Add a link
Reference in a new issue