Leaf Petersen
745f112ef6
Opt an initial batch of files under samples, samples-dev, utils, and runtime/tools/dartfuzz out of null safety in preparation for switching the flag on by default. Change-Id: Icdfd52a5a969e678a7205903332f73fe3841c223 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/166960 Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Leaf Petersen <leafp@google.com>
96 lines
2.7 KiB
Dart
96 lines
2.7 KiB
Dart
// Copyright (c) 2011, the Dart project authors. Please see the AUTHORS file
|
|
// for details. All rights reserved. Use of this source code is governed by a
|
|
// BSD-style license that can be found in the LICENSE file.
|
|
|
|
// @dart = 2.9
|
|
|
|
part of observable;
|
|
|
|
/** A change to an observable instance. */
|
|
class ChangeEvent {
|
|
// TODO(sigmund): capture language issues around enums & create a canonical
|
|
// Dart enum design.
|
|
/** Type denoting an in-place update event. */
|
|
static const UPDATE = 0;
|
|
|
|
/** Type denoting an insertion event. */
|
|
static const INSERT = 1;
|
|
|
|
/** Type denoting a single-remove event. */
|
|
static const REMOVE = 2;
|
|
|
|
/**
|
|
* Type denoting events that affect the entire observable instance. For
|
|
* example, a list operation like clear or sort.
|
|
*/
|
|
static const GLOBAL = 3;
|
|
|
|
/** The observable instance that changed. */
|
|
final Observable target;
|
|
|
|
/** Whether the change was an [INSERT], [REMOVE], or [UPDATE]. */
|
|
final int type;
|
|
|
|
/** The value after the change (or inserted value in a list). */
|
|
final newValue;
|
|
|
|
/** The value before the change (or removed value from a list). */
|
|
final oldValue;
|
|
|
|
/** Property that changed (null for list changes). */
|
|
final String propertyName;
|
|
|
|
/**
|
|
* Index of the list operation. Insertions prepend in front of the given
|
|
* index (insert at 0 means an insertion at the beginning of the list).
|
|
*/
|
|
final int index;
|
|
|
|
/** Factory constructor for property change events. */
|
|
ChangeEvent.property(
|
|
this.target, this.propertyName, this.newValue, this.oldValue)
|
|
: type = UPDATE,
|
|
index = null;
|
|
|
|
/** Factory constructor for list change events. */
|
|
ChangeEvent.list(
|
|
this.target, this.type, this.index, this.newValue, this.oldValue)
|
|
: propertyName = null;
|
|
|
|
/** Factory constructor for [GLOBAL] change events. */
|
|
ChangeEvent.global(this.target)
|
|
: type = GLOBAL,
|
|
newValue = null,
|
|
oldValue = null,
|
|
propertyName = null,
|
|
index = null;
|
|
}
|
|
|
|
/** A collection of change events on a single observable instance. */
|
|
class EventSummary {
|
|
final Observable target;
|
|
|
|
// TODO(sigmund): evolve this to track changes per property.
|
|
List<ChangeEvent> events;
|
|
|
|
EventSummary(this.target) : events = new List<ChangeEvent>();
|
|
|
|
void addEvent(ChangeEvent e) {
|
|
events.add(e);
|
|
}
|
|
|
|
/** Notify listeners of [target] and parents of [target] about all changes. */
|
|
void notify() {
|
|
if (!events.isEmpty) {
|
|
for (Observable obj = target; obj != null; obj = obj.parent) {
|
|
for (final listener in obj.listeners) {
|
|
listener(this);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/** A listener of change events. */
|
|
typedef void ChangeListener(EventSummary events);
|