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fix(core): fix the key/value differ
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fixes angular#15457
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@vicb
vicb committed Mar 28, 2017
1 parent 8e03f65 commit 75a9e57
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Showing 2 changed files with 129 additions and 112 deletions.
217 changes: 113 additions & 104 deletions packages/core/src/change_detection/differs/default_keyvalue_differ.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -27,13 +27,20 @@ export class DefaultKeyValueDifferFactory<K, V> implements KeyValueDifferFactory
}

export class DefaultKeyValueDiffer<K, V> implements KeyValueDiffer<K, V>, KeyValueChanges<K, V> {
private _records: Map<K, V> = new Map<K, V>();
private _records = new Map<K, KeyValueChangeRecord_<K, V>>();

private _mapHead: KeyValueChangeRecord_<K, V> = null;
// _appendAfter is used in the check loop
private _appendAfter: KeyValueChangeRecord_<K, V> = null;

private _previousMapHead: KeyValueChangeRecord_<K, V> = null;

private _changesHead: KeyValueChangeRecord_<K, V> = null;
private _changesTail: KeyValueChangeRecord_<K, V> = null;

private _additionsHead: KeyValueChangeRecord_<K, V> = null;
private _additionsTail: KeyValueChangeRecord_<K, V> = null;

private _removalsHead: KeyValueChangeRecord_<K, V> = null;
private _removalsTail: KeyValueChangeRecord_<K, V> = null;

Expand Down Expand Up @@ -90,67 +97,130 @@ export class DefaultKeyValueDiffer<K, V> implements KeyValueDiffer<K, V>, KeyVal

onDestroy() {}

/**
* Check the current state of the map vs the previous.
* The algorithm is optimised for when the keys do no change.
*/
check(map: Map<any, any>|{[k: string]: any}): boolean {
this._reset();
const records = this._records;
let oldSeqRecord: KeyValueChangeRecord_<K, V> = this._mapHead;
let lastOldSeqRecord: KeyValueChangeRecord_<K, V> = null;
let lastNewSeqRecord: KeyValueChangeRecord_<K, V> = null;
let seqChanged: boolean = false;

let insertBefore = this._mapHead;
this._appendAfter = null;

this._forEach(map, (value: any, key: any) => {
let newSeqRecord: any;
if (oldSeqRecord && key === oldSeqRecord.key) {
newSeqRecord = oldSeqRecord;
this._maybeAddToChanges(newSeqRecord, value);
if (insertBefore && insertBefore.key === key) {
this._maybeAddToChanges(insertBefore, value);
this._appendAfter = insertBefore;
insertBefore = insertBefore._next;
} else {
seqChanged = true;
if (oldSeqRecord !== null) {
this._removeFromSeq(lastOldSeqRecord, oldSeqRecord);
this._addToRemovals(oldSeqRecord);
}
if (records.has(key)) {
newSeqRecord = records.get(key);
this._maybeAddToChanges(newSeqRecord, value);
} else {
newSeqRecord = new KeyValueChangeRecord_<K, V>(key);
records.set(key, newSeqRecord);
newSeqRecord.currentValue = value;
this._addToAdditions(newSeqRecord);
}
const record = this._getOrCreateRecordForKey(key, value);
insertBefore = this._insertBeforeOrAppend(insertBefore, record);
}
});

if (seqChanged) {
if (this._isInRemovals(newSeqRecord)) {
this._removeFromRemovals(newSeqRecord);
}
if (lastNewSeqRecord == null) {
this._mapHead = newSeqRecord;
} else {
lastNewSeqRecord._next = newSeqRecord;
// Items remaining at the end of the list have been deleted
if (insertBefore) {
if (insertBefore._prev) {
insertBefore._prev._next = null;
}

this._removalsHead = insertBefore;
this._removalsTail = insertBefore;

for (let record = insertBefore; record !== null; record = record._nextRemoved) {
if (record === this._mapHead) {
this._mapHead = null;
}
this._records.delete(record.key);
record._nextRemoved = record._next;
record.previousValue = record.currentValue;
record.currentValue = null;
record._prev = null;
record._next = null;
}
lastOldSeqRecord = oldSeqRecord;
lastNewSeqRecord = newSeqRecord;
oldSeqRecord = oldSeqRecord && oldSeqRecord._next;
});
this._truncate(lastOldSeqRecord, oldSeqRecord);
}

return this.isDirty;
}

/**
* Inserts a record before `before` or append at the end of the list when `before` is null.
*
* Notes:
* - This method appends at `this._appendAfter`,
* - This method updates `this._appendAfter`,
* - The return value is the new value for the insertion pointer.
*/
private _insertBeforeOrAppend(
before: KeyValueChangeRecord_<K, V>,
record: KeyValueChangeRecord_<K, V>): KeyValueChangeRecord_<K, V> {
if (before) {
const prev = before._prev;
record._next = before;
record._prev = prev;
before._prev = record;
if (prev) {
prev._next = record;
}
if (before === this._mapHead) {
this._mapHead = record;
}

this._appendAfter = before;
return before;
}

if (this._appendAfter) {
this._appendAfter._next = record;
record._prev = this._appendAfter;
} else {
this._mapHead = record;
}

this._appendAfter = record;
return null;
}

private _getOrCreateRecordForKey(key: K, value: V): KeyValueChangeRecord_<K, V> {
if (this._records.has(key)) {
const record = this._records.get(key);
this._maybeAddToChanges(record, value);
const prev = record._prev;
const next = record._next;
if (prev) {
prev._next = next;
}
if (next) {
next._prev = prev;
}
record._next = null;
record._prev = null;

return record;
}

const record = new KeyValueChangeRecord_<K, V>(key);
this._records.set(key, record);
record.currentValue = value;
this._addToAdditions(record);
return record;
}

/** @internal */
_reset() {
if (this.isDirty) {
let record: KeyValueChangeRecord_<K, V>;
// Record the state of the mapping
for (record = this._previousMapHead = this._mapHead; record !== null; record = record._next) {
// let `_previousMapHead` contain the state of the map before the changes
this._previousMapHead = this._mapHead;
for (record = this._previousMapHead; record !== null; record = record._next) {
record._nextPrevious = record._next;
}

// Update `record.previousValue` with the value of the item before the changes
// We need to update all changed items (that's those which have been added and changed)
for (record = this._changesHead; record !== null; record = record._nextChanged) {
record.previousValue = record.currentValue;
}

for (record = this._additionsHead; record != null; record = record._nextAdded) {
record.previousValue = record.currentValue;
}
Expand All @@ -161,27 +231,7 @@ export class DefaultKeyValueDiffer<K, V> implements KeyValueDiffer<K, V>, KeyVal
}
}

private _truncate(lastRecord: KeyValueChangeRecord_<K, V>, record: KeyValueChangeRecord_<K, V>) {
while (record !== null) {
if (lastRecord === null) {
this._mapHead = null;
} else {
lastRecord._next = null;
}
const nextRecord = record._next;
this._addToRemovals(record);
lastRecord = record;
record = nextRecord;
}

for (let rec: KeyValueChangeRecord_<K, V> = this._removalsHead; rec !== null;
rec = rec._nextRemoved) {
rec.previousValue = rec.currentValue;
rec.currentValue = null;
this._records.delete(rec.key);
}
}

// Add the record or a given key to the list of changes only when the value has actually changed
private _maybeAddToChanges(record: KeyValueChangeRecord_<K, V>, newValue: any): void {
if (!looseIdentical(newValue, record.currentValue)) {
record.previousValue = record.currentValue;
Expand All @@ -190,47 +240,6 @@ export class DefaultKeyValueDiffer<K, V> implements KeyValueDiffer<K, V>, KeyVal
}
}

private _isInRemovals(record: KeyValueChangeRecord_<K, V>) {
return record === this._removalsHead || record._nextRemoved !== null ||
record._prevRemoved !== null;
}

private _addToRemovals(record: KeyValueChangeRecord_<K, V>) {
if (this._removalsHead === null) {
this._removalsHead = this._removalsTail = record;
} else {
this._removalsTail._nextRemoved = record;
record._prevRemoved = this._removalsTail;
this._removalsTail = record;
}
}

private _removeFromSeq(prev: KeyValueChangeRecord_<K, V>, record: KeyValueChangeRecord_<K, V>) {
const next = record._next;
if (prev === null) {
this._mapHead = next;
} else {
prev._next = next;
}
record._next = null;
}

private _removeFromRemovals(record: KeyValueChangeRecord_<K, V>) {
const prev = record._prevRemoved;
const next = record._nextRemoved;
if (prev === null) {
this._removalsHead = next;
} else {
prev._nextRemoved = next;
}
if (next === null) {
this._removalsTail = prev;
} else {
next._prevRemoved = prev;
}
record._prevRemoved = record._nextRemoved = null;
}

private _addToAdditions(record: KeyValueChangeRecord_<K, V>) {
if (this._additionsHead === null) {
this._additionsHead = this._additionsTail = record;
Expand Down Expand Up @@ -303,12 +312,12 @@ class KeyValueChangeRecord_<K, V> implements KeyValueChangeRecord<K, V> {
/** @internal */
_next: KeyValueChangeRecord_<K, V> = null;
/** @internal */
_prev: KeyValueChangeRecord_<K, V> = null;
/** @internal */
_nextAdded: KeyValueChangeRecord_<K, V> = null;
/** @internal */
_nextRemoved: KeyValueChangeRecord_<K, V> = null;
/** @internal */
_prevRemoved: KeyValueChangeRecord_<K, V> = null;
/** @internal */
_nextChanged: KeyValueChangeRecord_<K, V> = null;

constructor(public key: K) {}
Expand Down
24 changes: 16 additions & 8 deletions packages/core/test/change_detection/differs/default_keyvalue_differ_spec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -7,7 +7,6 @@
*/

import {DefaultKeyValueDiffer, DefaultKeyValueDifferFactory} from '@angular/core/src/change_detection/differs/default_keyvalue_differ';
import {afterEach, beforeEach, describe, expect, it} from '@angular/core/testing/src/testing_internal';
import {kvChangesAsString} from '../../change_detection/util';

// todo(vicb): Update the code & tests for object equality
Expand Down Expand Up @@ -55,21 +54,17 @@ export function main() {
});

it('should expose previous and current value', () => {
let previous: any /** TODO #9100 */, current: any /** TODO #9100 */;

m.set(1, 10);
differ.check(m);

m.set(1, 20);
differ.check(m);

differ.forEachChangedItem((record: any /** TODO #9100 */) => {
previous = record.previousValue;
current = record.currentValue;
differ.forEachChangedItem((record: any) => {
expect(record.previousValue).toEqual(10);
expect(record.currentValue).toEqual(20);
});

expect(previous).toEqual(10);
expect(current).toEqual(20);
});

it('should do basic map watching', () => {
Expand Down Expand Up @@ -198,6 +193,19 @@ export function main() {
changes: ['b[0->1]', 'a[0->1]']
}));
});

it('should when the first item is moved', () => {
differ.check({a: 'a', b: 'b'});
differ.check({c: 'c', a: 'a'});

expect(differ.toString()).toEqual(kvChangesAsString({
map: ['c[null->c]', 'a'],
previous: ['a', 'b[b->null]'],
additions: ['c[null->c]'],
removals: ['b[b->null]']
}));
});

});

describe('diff', () => {
Expand Down

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