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|
//! The various iterators this crate provides.
//!
//! These iterators are not a very stable interface and you really should
//! avoid considering them to be concrete types. A lot of the iterators in
//! this crate use `impl Iterator` for this reason but restrictions in the
//! language don't allow this to be used in all places on the versions of
//! rust this crate wants to compile for.
use std::marker::PhantomData;
use std::ops::{Index, Range};
use crate::{Change, ChangeTag, DiffOp, DiffTag};
/// Iterator for [`DiffOp::iter_changes`].
pub struct ChangesIter<'lookup, Old: ?Sized, New: ?Sized, T> {
old: &'lookup Old,
new: &'lookup New,
old_range: Range<usize>,
new_range: Range<usize>,
old_index: usize,
new_index: usize,
old_i: usize,
new_i: usize,
tag: DiffTag,
_marker: PhantomData<T>,
}
impl<'lookup, Old, New, T> ChangesIter<'lookup, Old, New, T>
where
Old: Index<usize, Output = T> + ?Sized,
New: Index<usize, Output = T> + ?Sized,
{
pub(crate) fn new(old: &'lookup Old, new: &'lookup New, op: DiffOp) -> Self {
let (tag, old_range, new_range) = op.as_tag_tuple();
let old_index = old_range.start;
let new_index = new_range.start;
let old_i = old_range.start;
let new_i = new_range.start;
ChangesIter {
old,
new,
old_range,
new_range,
old_index,
new_index,
old_i,
new_i,
tag,
_marker: PhantomData,
}
}
}
impl<'lookup, Old, New, T> Iterator for ChangesIter<'lookup, Old, New, T>
where
Old: Index<usize, Output = T> + ?Sized,
New: Index<usize, Output = T> + ?Sized,
T: Clone,
{
type Item = Change<T>;
fn next(&mut self) -> Option<Self::Item> {
match self.tag {
DiffTag::Equal => {
if self.old_i < self.old_range.end {
let value = self.old[self.old_i].clone();
self.old_i += 1;
self.old_index += 1;
self.new_index += 1;
Some(Change {
tag: ChangeTag::Equal,
old_index: Some(self.old_index - 1),
new_index: Some(self.new_index - 1),
value,
})
} else {
None
}
}
DiffTag::Delete => {
if self.old_i < self.old_range.end {
let value = self.old[self.old_i].clone();
self.old_i += 1;
self.old_index += 1;
Some(Change {
tag: ChangeTag::Delete,
old_index: Some(self.old_index - 1),
new_index: None,
value,
})
} else {
None
}
}
DiffTag::Insert => {
if self.new_i < self.new_range.end {
let value = self.new[self.new_i].clone();
self.new_i += 1;
self.new_index += 1;
Some(Change {
tag: ChangeTag::Insert,
old_index: None,
new_index: Some(self.new_index - 1),
value,
})
} else {
None
}
}
DiffTag::Replace => {
if self.old_i < self.old_range.end {
let value = self.old[self.old_i].clone();
self.old_i += 1;
self.old_index += 1;
Some(Change {
tag: ChangeTag::Delete,
old_index: Some(self.old_index - 1),
new_index: None,
value,
})
} else if self.new_i < self.new_range.end {
let value = self.new[self.new_i].clone();
self.new_i += 1;
self.new_index += 1;
Some(Change {
tag: ChangeTag::Insert,
old_index: None,
new_index: Some(self.new_index - 1),
value,
})
} else {
None
}
}
}
}
}
#[cfg(feature = "text")]
mod text {
use super::*;
/// Iterator for [`TextDiff::iter_all_changes`](crate::TextDiff::iter_all_changes).
pub struct AllChangesIter<'slf, 'data, T: ?Sized> {
old: &'slf [&'data T],
new: &'slf [&'data T],
ops: &'slf [DiffOp],
current_iter: Option<ChangesIter<'slf, [&'data T], [&'data T], &'data T>>,
}
impl<'slf, 'data, T> AllChangesIter<'slf, 'data, T>
where
T: 'data + ?Sized + PartialEq,
{
pub(crate) fn new(
old: &'slf [&'data T],
new: &'slf [&'data T],
ops: &'slf [DiffOp],
) -> Self {
AllChangesIter {
old,
new,
ops,
current_iter: None,
}
}
}
impl<'slf, 'data, T> Iterator for AllChangesIter<'slf, 'data, T>
where
T: PartialEq + 'data + ?Sized,
'data: 'slf,
{
type Item = Change<&'data T>;
fn next(&mut self) -> Option<Self::Item> {
loop {
if let Some(ref mut iter) = self.current_iter {
if let Some(rv) = iter.next() {
return Some(rv);
}
self.current_iter.take();
}
if let Some((&first, rest)) = self.ops.split_first() {
self.current_iter = Some(ChangesIter::new(self.old, self.new, first));
self.ops = rest;
} else {
return None;
}
}
}
}
}
#[cfg(feature = "text")]
pub use self::text::*;
|
