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Use lowest common ancestor search in History::changes_since

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Michael Davis 2022-11-27 12:46:36 -06:00 • committed by Blaž Hrastnik
parent 9a9e462183
commit 9387dfafed
1 changed files with 9 additions and 25 deletions
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34
helix-core/src/history.rs
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@ -122,32 +122,16 @@ impl History {
/// Returns the changes since the given revision composed into a transaction.
/// Returns None if there are no changes between the current and given revisions.
pub fn changes_since(&self, revision: usize) -> Option<Transaction> {
use std::cmp::Ordering::*;
let lca = self.lowest_common_ancestor(revision, self.current);
let up = self.path_up(revision, lca);
let down = self.path_up(self.current, lca);
let up_txns = up
.iter()
.rev()
.map(|&n| self.revisions[n].inversion.clone());
let down_txns = down.iter().map(|&n| self.revisions[n].transaction.clone());
match revision.cmp(&self.current) {
Equal => None,
Less => {
let mut child = self.revisions[revision].last_child?.get();
let mut transaction = self.revisions[child].transaction.clone();
while child != self.current {
child = self.revisions[child].last_child?.get();
transaction = transaction.compose(self.revisions[child].transaction.clone());
}
Some(transaction)
}
Greater => {
let mut inversion = self.revisions[revision].inversion.clone();
let mut parent = self.revisions[revision].parent;
while parent != self.current {
parent = self.revisions[parent].parent;
if parent == 0 {
return None;
}
inversion = inversion.compose(self.revisions[parent].inversion.clone());
}
Some(inversion)
}
}
up_txns.chain(down_txns).reduce(|acc, tx| tx.compose(acc))
}
/// Undo the last edit.