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use crate::sequence::sequence_apply_patch::apply_patch;
use crate::sequence::sequence_delta_patch_towards::delta_towards;
use crate::{CreatedDelta, Diffable, Patchable};
use serde::Serialize;
mod longest_common_subsequence;
mod sequence_apply_patch;
mod sequence_delta_patch_towards;
impl<'s, 'e, T: 'e + Diffable<'s, 'e, T>> Diffable<'s, 'e, Vec<T>> for Vec<T>
where
T: PartialEq,
&'e T: serde::Serialize,
{
type Delta = Vec<SequenceModificationDelta<'e, T>>;
type DeltaOwned = Vec<SequenceModificationDeltaOwned<T>>;
fn create_delta_towards(&self, end_state: &'e Self) -> CreatedDelta<Self::Delta> {
delta_towards(self, end_state)
}
}
impl<T> Patchable<Vec<SequenceModificationDeltaOwned<T>>> for Vec<T> {
fn apply_patch(&mut self, patch: Vec<SequenceModificationDeltaOwned<T>>) {
apply_patch(self, patch)
}
}
impl<'s, 'e, T: 'e + Diffable<'s, 'e, T>> Diffable<'s, 'e, [T]> for &[T]
where
T: PartialEq,
&'e T: serde::Serialize,
{
type Delta = Vec<SequenceModificationDelta<'e, T>>;
type DeltaOwned = Vec<SequenceModificationDeltaOwned<T>>;
fn create_delta_towards(&self, end_state: &'e [T]) -> CreatedDelta<Self::Delta> {
delta_towards(self, end_state)
}
}
/// Used to diff/patch sequences such as vectors and slices.
#[derive(Debug, Clone, Serialize)]
#[cfg_attr(test, derive(PartialEq))]
pub enum SequenceModificationDelta<'a, T>
where
&'a T: serde::Serialize,
{
/// Insert into the Vec<T>, starting at some start index.
InsertOne { index: usize, value: &'a T },
/// Prepend an item to the beginning of the vector.
PrependOne { item: &'a T },
/// Append item to the end of the new vector
AppendOne { item: &'a T },
/// Delete one item from the sequence
DeleteOne { index: usize },
/// Replace one item from the sequence
ReplaceOne { index: usize, new: &'a T },
// TODO: Heavily optimize small sequences. So we want operations like
// DeleteFirst, DeleteSecond ... DeleteFifth ... ReplaceThird ... etc.
/// Delete the first item in the sequence
DeleteFirst,
/// Delete the last item in the sequence
DeleteLast,
/// Replace the first item in the sequence
ReplaceFirst { item: &'a T },
/// Replace the last item in the sequence
ReplaceLast { item: &'a T },
/// Prepend many items to the beginning of the vector.
PrependMany { items: &'a [T] },
/// Insert multiple items into the Vec<T>, starting at some start index.
InsertMany { start_idx: usize, items: &'a [T] },
/// Delete from the Vec<T> starting from some start index
DeleteMany {
start_index: usize,
items_to_delete: usize,
},
/// Append item to the end of the new vector
AppendMany { items: &'a [T] },
/// Replace many items in the sequence.
ReplaceMany {
start_idx: usize,
items_to_replace: usize,
new: &'a [T],
},
/// Replace many items in the sequence when we are adding and removing the same number of
/// values.
ReplaceManySameAmountAddedAndRemoved { index: usize, new: &'a [T] },
/// Replace all of the values in the old sequence with the values in the new sequence.
/// Useful when there is no overlap between the start and end sequence.
ReplaceAll { new: &'a [T] },
/// Delete all items
DeleteAll,
/// Remove all items *at* AND *before* the specified index.
DeleteAllBeforeIncluding { end_index: usize },
/// Remove all items *at* AND *after* the specified index.
DeleteAllAfterIncluding { start_index: usize },
/// Replace all values before the provided index, inclusive.
ReplaceAllBeforeIncluding { before: usize, new: &'a [T] },
/// Replace all values after the provided index, inclusive.
ReplaceAllAfterIncluding { after: usize, new: &'a [T] },
}
/// Used to patch sequences such as vectors and slices.
#[derive(Debug, Clone, Serialize, Deserialize)]
#[cfg_attr(test, derive(PartialEq))]
pub enum SequenceModificationDeltaOwned<T> {
/// Insert into the Vec<T>, starting at some start index.
InsertOne { index: usize, value: T },
/// Prepend an item to the beginning of the vector.
PrependOne { item: T },
/// Append item to the end of the new vector
AppendOne { item: T },
/// Delete one item from the sequence
DeleteOne { index: usize },
/// Replace one item from the sequence
ReplaceOne { index: usize, new: T },
/// Delete the first item in the sequence
DeleteFirst,
/// Delete the last item in the sequence
DeleteLast,
/// Replace the first item in the sequence
ReplaceFirst { item: T },
/// Replace the last item in the sequence
ReplaceLast { item: T },
/// Prepend many items to the beginning of the vector.
PrependMany { items: Vec<T> },
/// Insert multiple items into the Vec<T>, starting at some start index.
InsertMany { start_idx: usize, items: Vec<T> },
/// Delete from the Vec<T> starting from some start index
DeleteMany {
start_index: usize,
items_to_delete: usize,
},
/// Append item to the end of the new vector
AppendMany { items: Vec<T> },
/// Replace many items in the sequence.
ReplaceMany {
start_idx: usize,
items_to_replace: usize,
new: Vec<T>,
},
/// Replace many items in the sequence when we are adding and removing the same number of
/// values.
ReplaceManySameAmountAddedAndRemoved { index: usize, new: Vec<T> },
/// Replace all of the values in the old sequence with the values in the new sequence.
ReplaceAll { new: Vec<T> },
/// Delete all items
DeleteAll,
/// Remove all items *at* AND *before* the specified index.
DeleteAllBeforeIncluding { end_index: usize },
/// Remove all items *at* AND *after* the specified index.
DeleteAllAfterIncluding { start_index: usize },
/// Replace all values before the provided index, inclusive.
ReplaceAllBeforeIncluding { before: usize, new: Vec<T> },
/// Replace all values after the provided index, inclusive.
ReplaceAllAfterIncluding { after: usize, new: Vec<T> },
}
#[cfg(test)]
mod tests {
use super::*;
use crate::dipa_impl_tester::DipaImplTester;
use bincode::Options;
/// 1 byte for the u8 length of the Vec that holds all of the patch operations
const BASE_PATCH_BYTES: usize = 1;
/// Verify that there is no diff if the start and end vector are the same.
#[test]
fn vec_unchanged() {
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3],
end: &vec![1u8, 2, 3],
expected_delta: vec![],
// No change, none variant is one byte
expected_serialized_patch_size: 1,
expected_did_change: false,
}
.test();
}
/// Verify that we delete one extra item at the end.
#[test]
fn deletion_one_at_end() {
// 1 for the variant
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1;
DipaImplTester {
label: None,
start: &mut vec![0u8, 1, 2, 3],
end: &vec![0u8, 1, 2],
expected_delta: vec![SequenceModificationDelta::DeleteLast],
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we delete many extra items at the end.
#[test]
fn deletion_many_at_end() {
// 1 for the variant then
// 1 bytes for the start index
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![0u8, 1, 2, 3, 4],
end: &vec![0u8, 1, 2],
expected_delta: vec![SequenceModificationDelta::DeleteAllAfterIncluding {
start_index: 3,
}],
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly delete the first item.
#[test]
fn delete_one_at_beginning() {
// 1 for the variant then
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1;
DipaImplTester {
label: None,
start: &mut vec![0u8, 1, 2],
end: &vec![1u8, 2],
expected_delta: vec![SequenceModificationDelta::DeleteFirst],
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly delete the first `n` items.
#[test]
fn delete_many_at_beginning() {
// 1 for the variant then
// 1 the index
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![0u8, 1, 2, 3],
end: &vec![2u8, 3],
expected_delta: vec![SequenceModificationDelta::DeleteAllBeforeIncluding {
end_index: 1,
}],
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we delete many extra items at the end.
#[test]
fn delete_many_beginning_and_many_end() {
// 2 for the two variants then
// 1 bytes for the end index
// 1 bytes for the start index
let expected_serialized_patch_size = BASE_PATCH_BYTES + 2 + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![0u8, 1, 2, 3, 4, 5],
end: &vec![2],
expected_delta: vec![
SequenceModificationDelta::DeleteAllAfterIncluding { start_index: 3 },
SequenceModificationDelta::DeleteAllBeforeIncluding { end_index: 1 },
],
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we delete one item in the middle.
#[test]
fn delete_one_in_middle() {
let expected_patch = vec![SequenceModificationDelta::DeleteOne { index: 1 }];
// 1 for the one variant in the vec, 1 index
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3],
end: &vec![1u8, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we delete many items in the middle.
#[test]
fn delete_many_in_middle() {
let expected_patch = vec![SequenceModificationDelta::DeleteMany {
start_index: 1,
items_to_delete: 2,
}];
// 1 for the one variant in the vec
// 1 for start idx
// 1 for item to delete count
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4],
end: &vec![1u8, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly go from an empty vec to one item in the vec.
#[test]
fn insert_one_into_empty_vec() {
let expected_patch = vec![SequenceModificationDelta::ReplaceAll { new: &[1] }];
// 1 for the one variant in the vec
// 1 for len of items vector
// 1 for the two u8's
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![],
end: &vec![1u8],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly go from an empty vec to 2 items in the vec.
#[test]
fn insert_many_into_empty_vec() {
let expected_patch = vec![SequenceModificationDelta::ReplaceAll { new: &[1, 2] }];
// 1 for the one variant in the vec
// 1 for len of items vector
// 2 for the two u8's
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![],
end: &vec![1u8, 2],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly insert one item at the beginning of the start sequence.
#[test]
fn insert_one_at_beginning() {
let expected_patch = vec![SequenceModificationDelta::PrependOne { item: &1 }];
// 1 for the one variant in the vec, 1 for the appended u8
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![2u8, 3],
end: &vec![1u8, 2, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly insert many items at the beginning of the start sequence.
#[test]
fn insert_many_at_beginning() {
let expected_patch = vec![SequenceModificationDelta::PrependMany { items: &[1, 2] }];
// 1 for the one variant in the vec
// 1 for the length of the items vector
// 2 for the prepended u8's
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![3u8, 4],
end: &vec![1u8, 2u8, 3, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we properly diff/patch inserting one item in the middle
#[test]
fn insert_one_in_middle() {
let expected_patch = vec![SequenceModificationDelta::InsertOne {
index: 1,
value: &2,
}];
// 1 for the one variant in the vec, 1 for the index, 1 for the appended u8
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1;
// If the start idx has advanced by 1 but the end index has advanced by 2 then
// insert one
DipaImplTester {
label: None,
start: &mut vec![1u8, 3],
end: &vec![1u8, 2, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Insert multiple items into the middle of the array.
#[test]
fn insert_many_in_middle() {
let expected_patch = vec![SequenceModificationDelta::InsertMany {
start_idx: 1,
items: &[2, 3],
}];
// 1 for the one variant in the vec
// 1 for the index
// 1 for length of items slice
// 2 for the appended u8's
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 4],
end: &vec![1u8, 2, 3, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we append one item to the end.
#[test]
fn append_one_at_end() {
let expected_patch = vec![SequenceModificationDelta::AppendOne { item: &3 }];
// 1 for the one variant in the vec, 1 for the appended u8
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2],
end: &vec![1u8, 2, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we create a patch to append many items to the end.
#[test]
fn append_many_at_end() {
let expected_patch = vec![SequenceModificationDelta::AppendMany { items: &[3, 4] }];
// 1 for the one variant in the modifications
// 1 for the length of the items vec
// 2 for the appended u8's
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2],
end: &vec![1u8, 2, 3, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace one item at the beginning of the array.
#[test]
fn replace_one_at_beginning() {
let expected_patch = vec![SequenceModificationDelta::ReplaceFirst { item: &2 }];
// 1 for the one variant in the modifications
// 1 for the item
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 3],
end: &vec![2u8, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace many items in the middle of the array.
#[test]
fn replace_many_at_beginning() {
let expected_patch = vec![SequenceModificationDelta::ReplaceAllBeforeIncluding {
before: 1,
new: &[5, 6],
}];
// 1 for the one variant in the modifications
// 1 for the index
// 1 for the items length
// 2 for the items
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4],
end: &vec![5u8, 6, 3, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace one item at the end of the array.
#[test]
fn replace_one_at_end() {
let expected_patch = vec![SequenceModificationDelta::ReplaceLast { item: &3 }];
// 1 for the one variant in the modifications
// 1 for the item
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2],
end: &vec![1u8, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace many items at the end of the array.
#[test]
fn replace_many_at_end() {
let expected_patch = vec![SequenceModificationDelta::ReplaceAllAfterIncluding {
after: 2,
new: &[5, 6],
}];
// 1 for the one variant in the modifications
// 1 for index
// 1 for the items length
// 2 for the items
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4],
end: &vec![1u8, 2, 5, 6],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace one item in the middle of the array.
#[test]
fn replace_one_in_middle() {
let expected_patch = vec![SequenceModificationDelta::ReplaceOne { index: 1, new: &4 }];
// 1 for the one variant in the modifications
// 1 for index
// 1 for the item
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3],
end: &vec![1u8, 4, 3],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can rename `n` items with `m` new items.
#[test]
fn replace_many_in_middle() {
let expected_patch = vec![SequenceModificationDelta::ReplaceMany {
start_idx: 1,
items_to_replace: 3,
new: &[6, 7],
}];
// 1 for the one variant in the modifications
// 1 for index
// 1 for items to replace count
// 1 for length of items
// 2 for the items
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4, 5],
end: &vec![1u8, 6, 7, 5],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we can replace many items in the middle of the array when we are removing just
/// as many items as we are adding.
#[test]
fn replace_many_in_middle_same_amount_added_and_removed() {
let expected_patch = vec![
SequenceModificationDelta::ReplaceManySameAmountAddedAndRemoved {
index: 1,
new: &[5, 6],
},
];
// 1 for the one variant in the modifications
// 1 for index
// 1 for items length
// 2 for the items
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1 + 1 + 1 + 2;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4],
end: &vec![1u8, 5, 6, 4],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that we create a patch to remove all items.
#[test]
fn delete_entire_vector() {
let expected_patch = vec![SequenceModificationDelta::DeleteAll];
// 1 for the one variant in the modifications
let expected_serialized_patch_size = BASE_PATCH_BYTES + 1;
DipaImplTester {
label: None,
start: &mut vec![1u8, 2, 3, 4],
end: &vec![],
expected_delta: expected_patch,
expected_serialized_patch_size,
expected_did_change: true,
}
.test();
}
/// Verify that only one byte is used to serialize a sequence modification variant.
///
/// This test guards against us accidentally adding more than 250 variants, at which point
/// bincode would begin to use 2 bytes instead of one.
#[test]
fn sequence_variant_one_byte() {
let diff: SequenceModificationDelta<()> = SequenceModificationDelta::DeleteFirst;
assert_eq!(
bincode::options()
.with_varint_encoding()
.serialize(&diff)
.unwrap()
.len(),
1
);
}
}