mirror of https://github.com/AMT-Cheif/drift.git
Remove DiffUtil and MoorAnimatedList
This commit is contained in:
Simon Binder
parent
c8ae99b52e
commit
138652fdc4
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/// A utility library to find an edit script that turns a list into another.
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/// This is useful when displaying a updating stream of immutable lists in a
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/// list that can be updated.
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@Deprecated('Will be removed in moor 2.0')
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library diff_util;
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import 'package:moor/src/utils/android_diffutils_port.dart' as impl;
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class EditAction {
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/// The index of the first list on which this action should be applied. If
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/// this action [isDelete], that index and the next [amount] indices should be
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/// deleted. Otherwise, this index should be moved back by [amount] and
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/// entries from the second list (starting at [indexFromOther]) should be
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/// inserted into the gap.
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final int index;
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/// The amount of entries affected by this action
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final int amount;
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/// If this action [isInsert], this is the first index from the second list
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/// from where the items should be taken from.
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final int indexFromOther;
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/// Whether this action should delete entries from the first list
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bool get isDelete => indexFromOther == null;
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/// Whether this action should insert entries into the first list
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bool get isInsert => indexFromOther != null;
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EditAction(this.index, this.amount, this.indexFromOther);
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@override
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String toString() {
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if (isDelete) {
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return 'EditAction: Delete $amount entries from the first list, starting '
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'at index $index';
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} else {
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return 'EditAction: Insert $amount entries into the first list, taking '
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'them from the second list starting at $indexFromOther. The entries '
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'should be written starting at index $index';
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}
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}
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}
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/// Finds the shortest edit script that turns list [a] into list [b].
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/// The implementation is ported from androids DiffUtil, which in turn
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/// implements a variation of Eugene W. Myer's difference algorithm. The
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/// algorithm is optimized for space and uses O(n) space to find the minimal
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/// number of addition and removal operations between the two lists. It has
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/// O(N + D^2) time performance, where D is the minimum amount of edits needed
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/// to turn a into b.
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List<EditAction> diff<T>(List<T> a, List<T> b,
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{bool Function(T a, T b) equals}) {
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final defaultEquals = equals ?? (T a, T b) => a == b;
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final snakes = impl.calculateDiff(impl.DiffInput<T>(a, b, defaultEquals));
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final actions = <EditAction>[];
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var posOld = a.length;
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var posNew = b.length;
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for (var snake in snakes.reversed) {
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final snakeSize = snake.size;
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final endX = snake.x + snakeSize;
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final endY = snake.y + snakeSize;
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if (endX < posOld) {
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// starting (including) with index endX, delete posOld - endX chars from a
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actions.add(EditAction(endX, posOld - endX, null));
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}
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if (endY < posNew) {
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// starting with index endX, insert posNex - endY characters into a. The
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// characters should be taken from b, starting (including) at the index
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// endY. The char that was at index endX should be pushed back.
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actions.add(EditAction(endX, posNew - endY, endY));
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}
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posOld = snake.x;
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posNew = snake.y;
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}
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return actions;
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}
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@ -1,249 +0,0 @@
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// ignore_for_file: cascade_invocations
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/*
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This implementation is copied from the DiffUtil class of the android support
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library, available at https://chromium.googlesource.com/android_tools/+/refs/heads/master/sdk/sources/android-25/android/support/v7/util/DiffUtil.java
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It has the following license:
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* Copyright (C) 2016 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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class Snake {
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int x;
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int y;
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int size;
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bool removal;
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bool reverse;
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}
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class Range {
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int oldListStart, oldListEnd;
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int newListStart, newListEnd;
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Range.nullFields();
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Range(this.oldListStart, this.oldListEnd, this.newListStart, this.newListEnd);
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}
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class DiffInput<T> {
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final List<T> from;
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final List<T> to;
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final bool Function(T a, T b) equals;
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DiffInput(this.from, this.to, this.equals);
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bool areItemsTheSame(int fromPos, int toPos) {
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return equals(from[fromPos], to[toPos]);
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}
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}
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@Deprecated('Will be removed in moor 2.0')
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List<Snake> calculateDiff(DiffInput input) {
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final oldSize = input.from.length;
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final newSize = input.to.length;
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final snakes = <Snake>[];
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final stack = <Range>[];
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stack.add(Range(0, oldSize, 0, newSize));
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final max = oldSize + newSize + (oldSize - newSize).abs();
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final forward = List<int>(max * 2);
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final backward = List<int>(max * 2);
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final rangePool = <Range>[];
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while (stack.isNotEmpty) {
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final range = stack.removeLast();
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final snake = _diffPartial(input, range.oldListStart, range.oldListEnd,
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range.newListStart, range.newListEnd, forward, backward, max);
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if (snake != null) {
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if (snake.size > 0) {
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snakes.add(snake);
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}
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// offset the snake to convert its coordinates from the Range's are to
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// global
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snake.x += range.oldListStart;
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snake.y += range.newListStart;
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// add new ranges for left and right
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final left =
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rangePool.isEmpty ? Range.nullFields() : rangePool.removeLast();
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left.oldListStart = range.oldListStart;
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left.newListStart = range.newListStart;
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if (snake.reverse) {
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left.oldListEnd = snake.x;
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left.newListEnd = snake.y;
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} else {
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if (snake.removal) {
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left.oldListEnd = snake.x - 1;
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left.newListEnd = snake.y;
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} else {
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left.oldListEnd = snake.x;
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left.newListEnd = snake.y - 1;
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}
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}
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stack.add(left);
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final right = range;
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if (snake.reverse) {
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if (snake.removal) {
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right.oldListStart = snake.x + snake.size + 1;
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right.newListStart = snake.y + snake.size;
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} else {
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right.oldListStart = snake.x + snake.size;
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right.newListStart = snake.y + snake.size + 1;
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}
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} else {
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right.oldListStart = snake.x + snake.size;
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right.newListStart = snake.y + snake.size;
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}
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stack.add(right);
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} else {
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rangePool.add(range);
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}
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}
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snakes.sort((a, b) {
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final cmpX = a.x - b.x;
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return cmpX == 0 ? a.y - b.y : cmpX;
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});
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// add root snake
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final first = snakes.isEmpty ? null : snakes.first;
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if (first == null || first.x != 0 || first.y != 0) {
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snakes.insert(
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0,
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Snake()
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..x = 0
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..y = 0
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..removal = false
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..size = 0
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..reverse = false);
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}
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return snakes;
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}
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Snake _diffPartial(DiffInput input, int startOld, int endOld, int startNew,
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int endNew, List<int> forward, List<int> backward, int kOffset) {
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final oldSize = endOld - startOld;
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final newSize = endNew - startNew;
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if (endOld - startOld < 1 || endNew - startNew < 1) return null;
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final delta = oldSize - newSize;
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final dLimit = (oldSize + newSize + 1) ~/ 2;
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forward.fillRange(kOffset - dLimit - 1, kOffset + dLimit + 1, 0);
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backward.fillRange(
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kOffset - dLimit - 1 + delta, kOffset + dLimit + 1 + delta, oldSize);
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final checkInFwd = delta.isOdd;
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for (var d = 0; d <= dLimit; d++) {
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for (var k = -d; k <= d; k += 2) {
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// find forward path
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// we can reach k from k - 1 or k + 1. Check which one is further in the
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// graph.
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int x;
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bool removal;
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if (k == -d ||
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k != d && forward[kOffset + k - 1] < forward[kOffset + k + 1]) {
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x = forward[kOffset + k + 1];
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removal = false;
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} else {
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x = forward[kOffset + k - 1] + 1;
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removal = true;
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}
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// set y based on x
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var y = x - k;
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// move diagonal as long as items match
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while (x < oldSize &&
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y < newSize &&
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input.areItemsTheSame(startOld + x, startNew + y)) {
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x++;
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y++;
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}
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forward[kOffset + k] = x;
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if (checkInFwd && k >= delta - d + 1 && k <= delta + d - 1) {
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if (forward[kOffset + k] >= backward[kOffset + k]) {
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final outSnake = Snake()..x = backward[kOffset + k];
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outSnake
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..y = outSnake.x - k
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..size = forward[kOffset + k] - backward[kOffset + k]
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..removal = removal
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..reverse = false;
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return outSnake;
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}
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}
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}
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for (var k = -d; k <= d; k += 2) {
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// find reverse path at k + delta, in reverse
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final backwardK = k + delta;
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int x;
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bool removal;
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if (backwardK == d + delta ||
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backwardK != -d + delta &&
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backward[kOffset + backwardK - 1] <
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backward[kOffset + backwardK + 1]) {
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x = backward[kOffset + backwardK - 1];
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removal = false;
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} else {
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x = backward[kOffset + backwardK + 1] - 1;
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removal = true;
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}
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// set y based on x
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var y = x - backwardK;
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// move diagonal as long as items match
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while (x > 0 &&
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y > 0 &&
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input.areItemsTheSame(startOld + x - 1, startNew + y - 1)) {
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x--;
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y--;
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}
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backward[kOffset + backwardK] = x;
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if (!checkInFwd && k + delta >= -d && k + delta <= d) {
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if (forward[kOffset + backwardK] >= backward[kOffset + backwardK]) {
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final outSnake = Snake()..x = backward[kOffset + backwardK];
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outSnake
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..y = outSnake.x - backwardK
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..size =
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forward[kOffset + backwardK] - backward[kOffset + backwardK]
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..removal = removal
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..reverse = true;
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return outSnake;
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}
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}
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}
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}
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throw StateError("Unexpected case: Please make sure the lists don't change "
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'during a diff');
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}
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@ -1,28 +0,0 @@
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import 'package:test_api/test_api.dart';
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import 'package:moor/diff_util.dart';
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List<T> applyEditScript<T>(List<T> a, List<T> b, List<EditAction> actions) {
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final copy = List.of(a);
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for (var action in actions) {
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if (action.isDelete) {
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final deleteStartIndex = action.index;
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copy.removeRange(deleteStartIndex, deleteStartIndex + action.amount);
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} else if (action.isInsert) {
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final toAdd = b.getRange(
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action.indexFromOther, action.indexFromOther + action.amount);
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copy.insertAll(action.index, toAdd);
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}
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}
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return copy;
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}
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void main() {
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final a = ['a', 'b', 'c', 'a', 'b', 'b', 'a'];
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final b = ['c', 'b', 'a', 'b', 'a', 'c'];
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test('diff matcher should produce a correct edit script', () {
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expect(applyEditScript(a, b, diff(a, b)), b);
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});
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}
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@ -12,7 +12,6 @@ import 'package:moor/moor.dart';
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import 'package:moor/backends.dart';
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import 'package:moor/backends.dart';
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import 'package:sqflite/sqflite.dart' as s;
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import 'package:sqflite/sqflite.dart' as s;
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export 'package:moor_flutter/src/animated_list.dart';
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export 'package:moor/moor.dart';
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export 'package:moor/moor.dart';
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/// Signature of a function that runs when a database doesn't exist on file.
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/// Signature of a function that runs when a database doesn't exist on file.
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@ -1,131 +0,0 @@
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import 'dart:async';
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import 'package:flutter/widgets.dart';
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// ignore: deprecated_member_use
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import 'package:moor/diff_util.dart';
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typedef Widget ItemBuilder<T>(
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BuildContext context, T item, Animation<double> anim);
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typedef Widget RemovedItemBuilder<T>(
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BuildContext context, T item, Animation<double> anim);
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/// An [AnimatedList] that shows the result of a moor query stream.
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@Deprecated('Will be removed in moor 2.0. You could use the '
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'animated_stream_list package as an alternative')
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class MoorAnimatedList<T> extends StatefulWidget {
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final Stream<List<T>> stream;
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final ItemBuilder<T> itemBuilder;
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|
||||||
final RemovedItemBuilder<T> removedItemBuilder;
|
|
||||||
|
|
||||||
/// A function that decides whether two items are considered equal. By
|
|
||||||
/// default, `a == b` will be used. A customization is useful if the content
|
|
||||||
/// of items can change (e.g. when a title changes, you'd only want to change
|
|
||||||
/// one text and not let the item disappear to show up again).
|
|
||||||
final bool Function(T a, T b) equals;
|
|
||||||
|
|
||||||
MoorAnimatedList(
|
|
||||||
{@required this.stream,
|
|
||||||
@required this.itemBuilder,
|
|
||||||
@required this.removedItemBuilder,
|
|
||||||
this.equals});
|
|
||||||
|
|
||||||
@override
|
|
||||||
_MoorAnimatedListState<T> createState() {
|
|
||||||
return _MoorAnimatedListState<T>();
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
class _MoorAnimatedListState<T> extends State<MoorAnimatedList<T>> {
|
|
||||||
List<T> _lastSnapshot;
|
|
||||||
int _initialItemCount;
|
|
||||||
|
|
||||||
StreamSubscription _subscription;
|
|
||||||
|
|
||||||
final GlobalKey<AnimatedListState> _key = GlobalKey();
|
|
||||||
AnimatedListState get listState => _key.currentState;
|
|
||||||
|
|
||||||
@override
|
|
||||||
void initState() {
|
|
||||||
_setupSubscription();
|
|
||||||
super.initState();
|
|
||||||
}
|
|
||||||
|
|
||||||
void _receiveData(List<T> data) {
|
|
||||||
if (listState == null) {
|
|
||||||
setState(() {
|
|
||||||
_lastSnapshot = data;
|
|
||||||
_initialItemCount = data.length;
|
|
||||||
});
|
|
||||||
return;
|
|
||||||
}
|
|
||||||
|
|
||||||
if (_lastSnapshot == null) {
|
|
||||||
// no diff possible. Initialize lists instead of diffing
|
|
||||||
_lastSnapshot = data;
|
|
||||||
for (var i = 0; i < data.length; i++) {
|
|
||||||
listState.insertItem(i);
|
|
||||||
}
|
|
||||||
} else {
|
|
||||||
final editScript = diff(_lastSnapshot, data, equals: widget.equals);
|
|
||||||
|
|
||||||
for (var action in editScript) {
|
|
||||||
if (action.isDelete) {
|
|
||||||
// we need to delete action.amount items at index action.index
|
|
||||||
for (var i = 0; i < action.amount; i++) {
|
|
||||||
// i items have already been deleted, so + 1 for the index. Notice
|
|
||||||
// that we don't have to do this when calling removeItem on the
|
|
||||||
// animated list state, as it will reflect the operation immediately.
|
|
||||||
final itemHere = _lastSnapshot[action.index + i];
|
|
||||||
listState.removeItem(action.index, (ctx, anim) {
|
|
||||||
return widget.removedItemBuilder(ctx, itemHere, anim);
|
|
||||||
});
|
|
||||||
}
|
|
||||||
} else {
|
|
||||||
for (var i = 0; i < action.amount; i++) {
|
|
||||||
listState.insertItem(action.index + i);
|
|
||||||
}
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
setState(() {
|
|
||||||
_lastSnapshot = data;
|
|
||||||
});
|
|
||||||
}
|
|
||||||
}
|
|
||||||
|
|
||||||
void _setupSubscription() {
|
|
||||||
_subscription = widget.stream.listen(_receiveData);
|
|
||||||
}
|
|
||||||
|
|
||||||
@override
|
|
||||||
void didUpdateWidget(MoorAnimatedList<T> oldWidget) {
|
|
||||||
_subscription?.cancel();
|
|
||||||
_lastSnapshot = null;
|
|
||||||
_setupSubscription();
|
|
||||||
|
|
||||||
super.didUpdateWidget(oldWidget);
|
|
||||||
}
|
|
||||||
|
|
||||||
@override
|
|
||||||
void dispose() {
|
|
||||||
_subscription?.cancel();
|
|
||||||
super.dispose();
|
|
||||||
}
|
|
||||||
|
|
||||||
@override
|
|
||||||
Widget build(BuildContext context) {
|
|
||||||
if (_lastSnapshot == null) return const SizedBox();
|
|
||||||
|
|
||||||
return AnimatedList(
|
|
||||||
key: _key,
|
|
||||||
initialItemCount: _initialItemCount ?? 0,
|
|
||||||
itemBuilder: (ctx, index, anim) {
|
|
||||||
final item = _lastSnapshot[index];
|
|
||||||
final child = widget.itemBuilder(ctx, item, anim);
|
|
||||||
|
|
||||||
return child;
|
|
||||||
},
|
|
||||||
);
|
|
||||||
}
|
|
||||||
}
|
|
||||||
Loading…
Reference in New Issue