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feat(sdk): Map Update::RemoveItem into VectorDiff::Remove in `Upd…
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…ateToVectorDiff`.

This patch implements the support of `Update::RemoveItem` inside
`UpdateToVectorDiff` to emit a `VectorDiff::Remove`.
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Hywan committed Oct 28, 2024
1 parent bcec08e commit 74283ea
Showing 1 changed file with 100 additions and 7 deletions.
107 changes: 100 additions & 7 deletions crates/matrix-sdk/src/event_cache/linked_chunk/as_vector.rs
Original file line number Diff line number Diff line change
Expand Up @@ -356,8 +356,19 @@ impl UpdateToVectorDiff {
}
}

Update::RemoveItem { at } => {
todo!()
Update::RemoveItem { at: position } => {
let (offset, (_chunk_index, chunk_length)) = self.map_to_offset(position);

// Remove one item to the chunk in `self.chunks`.
*chunk_length -= 1;

// See `reattaching` to learn more.
if reattaching {
continue;
}

// Let's emit a `VectorDiff::Remove`.
diffs.push(VectorDiff::Remove { index: offset });
}

Update::DetachLastItems { at: position } => {
Expand Down Expand Up @@ -456,6 +467,9 @@ mod tests {
match diff {
VectorDiff::Insert { index, value } => accumulator.insert(index, value),
VectorDiff::Append { values } => accumulator.append(values),
VectorDiff::Remove { index } => {
accumulator.remove(index);
}
diff => unimplemented!("{diff:?}"),
}
}
Expand Down Expand Up @@ -599,15 +613,77 @@ mod tests {
&[VectorDiff::Insert { index: 0, value: 'm' }],
);

let removed_item = linked_chunk
.remove_item_at(linked_chunk.item_position(|item| *item == 'c').unwrap())
.unwrap();
assert_eq!(removed_item, 'c');
assert_items_eq!(
linked_chunk,
['m', 'a', 'w'] ['x'] ['y', 'z', 'b'] ['d'] ['i', 'j', 'k'] ['l'] ['e', 'f', 'g'] ['h']
);

// From an `ObservableVector` point of view, it would look like:
//
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// | m | a | w | x | y | z | b | d | i | j | k | l | e | f | g | h |
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// ^
// |
// `c` has been removed
apply_and_assert_eq(&mut accumulator, as_vector.take(), &[VectorDiff::Remove { index: 7 }]);

let removed_item = linked_chunk
.remove_item_at(linked_chunk.item_position(|item| *item == 'z').unwrap())
.unwrap();
assert_eq!(removed_item, 'z');
assert_items_eq!(
linked_chunk,
['m', 'a', 'w'] ['x'] ['y', 'b'] ['d'] ['i', 'j', 'k'] ['l'] ['e', 'f', 'g'] ['h']
);

// From an `ObservableVector` point of view, it would look like:
//
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// | m | a | w | x | y | b | d | i | j | k | l | e | f | g | h |
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// ^
// |
// `z` has been removed
apply_and_assert_eq(&mut accumulator, as_vector.take(), &[VectorDiff::Remove { index: 5 }]);

linked_chunk
.insert_items_at(['z'], linked_chunk.item_position(|item| *item == 'h').unwrap())
.unwrap();

assert_items_eq!(
linked_chunk,
['m', 'a', 'w'] ['x'] ['y', 'b'] ['d'] ['i', 'j', 'k'] ['l'] ['e', 'f', 'g'] ['z', 'h']
);

// From an `ObservableVector` point of view, it would look like:
//
// 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// | m | a | w | x | y | b | d | i | j | k | l | e | f | g | z | h |
// +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
// ^^^^
// |
// new!
apply_and_assert_eq(
&mut accumulator,
as_vector.take(),
&[VectorDiff::Insert { index: 14, value: 'z' }],
);

drop(linked_chunk);
assert!(as_vector.take().is_empty());

// Finally, ensure the “reconstitued” vector is the one expected.
assert_eq!(
accumulator,
vector![
'm', 'a', 'w', 'x', 'y', 'z', 'b', 'c', 'd', 'i', 'j', 'k', 'l', 'e', 'f', 'g', 'h'
]
vector!['m', 'a', 'w', 'x', 'y', 'b', 'd', 'i', 'j', 'k', 'l', 'e', 'f', 'g', 'z', 'h']
);
}

Expand Down Expand Up @@ -643,6 +719,7 @@ mod tests {
PushItems { items: Vec<char> },
PushGap,
ReplaceLastGap { items: Vec<char> },
RemoveItem { item: char },
}

fn as_vector_operation_strategy() -> impl Strategy<Value = AsVectorOperation> {
Expand All @@ -654,13 +731,16 @@ mod tests {

1 => prop::collection::vec(prop::char::ranges(vec!['a'..='z', 'A'..='Z'].into()), 0..=25)
.prop_map(|items| AsVectorOperation::ReplaceLastGap { items }),

1 => prop::char::ranges(vec!['a'..='z', 'A'..='Z'].into())
.prop_map(|item| AsVectorOperation::RemoveItem { item }),
]
}

proptest! {
#[test]
fn as_vector_is_correct(
operations in prop::collection::vec(as_vector_operation_strategy(), 10..=50)
operations in prop::collection::vec(as_vector_operation_strategy(), 50..=200)
) {
let mut linked_chunk = LinkedChunk::<10, char, ()>::new_with_update_history();
let mut as_vector = linked_chunk.as_vector().unwrap();
Expand All @@ -683,7 +763,17 @@ mod tests {
continue;
};

linked_chunk.replace_gap_at(items, gap_identifier).unwrap();
linked_chunk.replace_gap_at(items, gap_identifier).expect("Failed to replace a gap");
}

AsVectorOperation::RemoveItem { item: expected_item } => {
let Some(position) = linked_chunk
.items().find_map(|(position, item)| (*item == expected_item).then_some(position))
else {
continue;
};

linked_chunk.remove_item_at(position).expect("Failed to remove an item");
}
}
}
Expand All @@ -699,6 +789,9 @@ mod tests {

vector_from_diffs.append(&mut values);
}
VectorDiff::Remove { index } => {
vector_from_diffs.remove(index);
}
_ => unreachable!(),
}
}
Expand Down

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