61 lines
1.7 KiB
Rust
61 lines
1.7 KiB
Rust
use crate::op_tree::OpTreeInternal;
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use crate::query::VisWindow;
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use crate::types::{Clock, Key};
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use std::fmt::Debug;
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#[derive(Debug)]
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pub(crate) struct KeysAt<'a> {
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clock: Clock,
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window: VisWindow,
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index: usize,
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last_key: Option<Key>,
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index_back: usize,
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last_key_back: Option<Key>,
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op_tree: &'a OpTreeInternal,
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}
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impl<'a> KeysAt<'a> {
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pub(crate) fn new(op_tree: &'a OpTreeInternal, clock: Clock) -> Self {
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Self {
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clock,
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window: VisWindow::default(),
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index: 0,
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last_key: None,
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index_back: op_tree.len(),
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last_key_back: None,
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op_tree,
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}
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}
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}
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impl<'a> Iterator for KeysAt<'a> {
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type Item = Key;
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fn next(&mut self) -> Option<Self::Item> {
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for i in self.index..self.index_back {
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let op = self.op_tree.get(i)?;
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let visible = self.window.visible_at(op, i, &self.clock);
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self.index += 1;
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if Some(op.elemid_or_key()) != self.last_key && visible {
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self.last_key = Some(op.elemid_or_key());
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return Some(op.elemid_or_key());
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}
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}
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None
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}
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}
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impl<'a> DoubleEndedIterator for KeysAt<'a> {
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fn next_back(&mut self) -> Option<Self::Item> {
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for i in self.index..self.index_back {
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let op = self.op_tree.get(i)?;
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let visible = self.window.visible_at(op, i, &self.clock);
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self.index_back -= 1;
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if Some(op.elemid_or_key()) != self.last_key_back && visible {
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self.last_key_back = Some(op.elemid_or_key());
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return Some(op.elemid_or_key());
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}
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}
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None
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}
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}
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