Transaction: Add a changes_iter() that can convert back to a list of Changes

pull/11/head
Blaž Hrastnik 4 years ago
parent a74ff6bc03
commit 1d96cbfbd2

@ -390,6 +390,10 @@ impl ChangeSet {
} }
new_pos new_pos
} }
pub fn changes_iter(&self) -> ChangeIterator {
ChangeIterator::new(self)
}
} }
/// Transaction represents a single undoable unit of changes. Several changes can be grouped into /// Transaction represents a single undoable unit of changes. Several changes can be grouped into
@ -502,6 +506,10 @@ impl Transaction {
(range.head, range.head, Some(text.clone())) (range.head, range.head, Some(text.clone()))
}) })
} }
pub fn changes_iter(&self) -> ChangeIterator {
self.changes.changes_iter()
}
} }
impl From<ChangeSet> for Transaction { impl From<ChangeSet> for Transaction {
@ -513,6 +521,51 @@ impl From<ChangeSet> for Transaction {
} }
} }
pub struct ChangeIterator<'a> {
iter: std::iter::Peekable<std::slice::Iter<'a, Operation>>,
pos: usize,
}
impl<'a> ChangeIterator<'a> {
fn new(changeset: &'a ChangeSet) -> Self {
let iter = changeset.changes.iter().peekable();
Self { iter, pos: 0 }
}
}
impl<'a> Iterator for ChangeIterator<'a> {
type Item = Change;
fn next(&mut self) -> Option<Self::Item> {
use Operation::*;
loop {
match self.iter.next()? {
Retain(len) => {
self.pos += len;
}
Delete(len) => {
let start = self.pos;
self.pos += len;
return Some((start, self.pos, None));
}
Insert(s) => {
let start = self.pos;
// a subsequent delete means a replace, consume it
if let Some(Delete(len)) = self.iter.peek() {
self.iter.next();
self.pos += len;
return Some((start, self.pos, Some(s.clone())));
} else {
return Some((start, start, Some(s.clone())));
}
}
}
}
}
}
#[cfg(test)] #[cfg(test)]
mod test { mod test {
use super::*; use super::*;
@ -626,6 +679,14 @@ mod test {
assert_eq!(state.doc, Rope::from_str("hello void! 123")); assert_eq!(state.doc, Rope::from_str("hello void! 123"));
} }
#[test]
fn changes_iter() {
let mut state = State::new("hello world!\ntest 123".into());
let changes = vec![(6, 11, Some("void".into())), (12, 17, None)];
let transaction = Transaction::change(&state.doc, changes.clone().into_iter());
assert_eq!(transaction.changes_iter().collect::<Vec<_>>(), changes);
}
#[test] #[test]
fn optimized_composition() { fn optimized_composition() {
let mut state = State::new("".into()); let mut state = State::new("".into());

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