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Unified Diff: client/observable/observable.dart

Issue 9382027: Move client/{base, observable, layout, touch, util, view} to samples/ui_lib . (Closed) Base URL: http://dart.googlecode.com/svn/branches/bleeding_edge/dart/
Patch Set: '' Created 8 years, 10 months ago
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Index: client/observable/observable.dart
===================================================================
--- client/observable/observable.dart (revision 4144)
+++ client/observable/observable.dart (working copy)
@@ -1,299 +0,0 @@
-// 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.
-
-#library('observable');
-
-#import('dart:coreimpl');
-
-#source('ChangeEvent.dart');
-#source('EventBatch.dart');
-
-/**
- * An object whose changes are tracked and who can issue events notifying how it
- * has been changed.
- */
-interface Observable {
- /** Returns a globally unique identifier for the object. */
- // TODO(sigmund): remove once dart supports maps with arbitrary keys.
- final int uid;
-
- /** Listeners on this model. */
- final List<ChangeListener> listeners;
-
- /** The parent observable to notify when this child is changed. */
- final Observable parent;
-
- /**
- * Adds a listener for changes on this observable instance. Returns whether
- * the listener was added successfully.
- */
- bool addChangeListener(ChangeListener listener);
-
- /**
- * Removes a listener for changes on this observable instance. Returns whether
- * the listener was removed successfully.
- */
- bool removeChangeListener(ChangeListener listener);
-}
-
-
-/** Common functionality for observable objects. */
-class AbstractObservable implements Observable {
-
- /** Unique id to identify this model in an event batch. */
- final int uid;
-
- /** The parent observable to notify when this child is changed. */
- final Observable parent;
-
- /** Listeners on this model. */
- List<ChangeListener> listeners;
-
- /** Whether this object is currently observed by listeners or propagators. */
- bool get isObserved() {
- for (Observable obj = this; obj != null; obj = obj.parent) {
- if (listeners.length > 0) {
- return true;
- }
- }
- return false;
- }
-
- AbstractObservable([Observable this.parent = null])
- : uid = EventBatch.genUid(),
- listeners = new List<ChangeListener>();
-
- bool addChangeListener(ChangeListener listener) {
- if (listeners.indexOf(listener, 0) == -1) {
- listeners.add(listener);
- return true;
- }
-
- return false;
- }
-
- bool removeChangeListener(ChangeListener listener) {
- // TODO(rnystrom): This is awkward without List.remove(e).
- if (listeners.indexOf(listener, 0) != -1) {
- bool found = false;
- listeners = listeners.filter((e) => found || !(found = (e == listener)));
- return true;
- } else {
- return false;
- }
- }
-
- void recordPropertyUpdate(String propertyName, newValue, oldValue) {
- recordEvent(new ChangeEvent.property(
- this, propertyName, newValue, oldValue));
- }
-
- void recordListUpdate(int index, newValue, oldValue) {
- recordEvent(new ChangeEvent.list(
- this, ChangeEvent.UPDATE, index, newValue, oldValue));
- }
-
- void recordListInsert(int index, newValue) {
- recordEvent(new ChangeEvent.list(
- this, ChangeEvent.INSERT, index, newValue, null));
- }
-
- void recordListRemove(int index, oldValue) {
- recordEvent(new ChangeEvent.list(
- this, ChangeEvent.REMOVE, index, null, oldValue));
- }
-
- void recordGlobalChange() {
- recordEvent(new ChangeEvent.global(this));
- }
-
- void recordEvent(ChangeEvent event) {
- // Bail if no one cares about the event.
- if (!isObserved) {
- return;
- }
-
- if (EventBatch.current != null) {
- // Already in a batch, so just add it.
- assert (!EventBatch.current.sealed);
- // TODO(sigmund): measure the performance implications of this indirection
- // and consider whether caching the summary object in this instance helps.
- var summary = EventBatch.current.getEvents(this);
- summary.addEvent(event);
- } else {
- // Not in a batch, so create a one-off one.
- // TODO(rnystrom): Needing to do ignore and (null) here is awkward.
- EventBatch.wrap((ignore) { recordEvent(event); })(null);
- }
- }
-}
-
-/** A growable list that fires events when it's modified. */
-class ObservableList<T>
- extends AbstractObservable
- implements List<T>, Observable {
-
- /** Underlying list. */
- // TODO(rnystrom): Make this final if we get list.remove().
- List<T> _internal;
-
- ObservableList([Observable parent = null])
- : super(parent), _internal = new List<T>();
-
- T operator [](int index) => _internal[index];
-
- void operator []=(int index, T value) {
- recordListUpdate(index, value, _internal[index]);
- _internal[index] = value;
- }
-
- int get length() => _internal.length;
-
- void set length(int value) {
- _internal.length = value;
- recordGlobalChange();
- }
-
- void clear() {
- _internal.clear();
- recordGlobalChange();
- }
-
- void sort(int compare(Object a, Object b)) {
- _internal.sort(compare);
- recordGlobalChange();
- }
-
- void add(T element) {
- recordListInsert(length, element);
- _internal.add(element);
- }
-
- void addLast(T element) {
- add(element);
- }
-
- void addAll(Collection<T> elements) {
- for (T element in elements) {
- add(element);
- }
- }
-
- int push(T element) {
- recordListInsert(length, element);
- _internal.add(element);
- return _internal.length;
- }
-
- T last() => _internal.last();
-
- T removeLast() {
- final result = _internal.removeLast();
- recordListRemove(length, result);
- return result;
- }
-
- T removeAt(int index) {
- int i = 0;
- T found = null;
- _internal = _internal.filter(bool _(element) {
- if (i++ == index) {
- found = element;
- return false;
- }
- return true;
- });
- if (found != null) {
- recordListRemove(index, found);
- }
- return found;
- }
-
- int indexOf(T element, [int start = 0]) {
- return _internal.indexOf(element, start);
- }
-
- int lastIndexOf(T element, [int start = null]) {
- if (start === null) start = length - 1;
- return _internal.lastIndexOf(element, start);
- }
-
- bool removeFirstElement(T element) {
- // the removeAt above will record the event.
- return (removeAt(indexOf(element, 0)) != null);
- }
-
- int removeAllElements(T element) {
- int count = 0;
- for (int i = 0; i < length; i++) {
- if (_internal[i] == element) {
- // the removeAt above will record the event.
- removeAt(i);
- // adjust index since remove shifted elements.
- i--;
- count++;
- }
- }
- return count;
- }
-
- void copyFrom(List<T> src, int srcStart, int dstStart, int count) {
- Arrays.copy(src, srcStart, this, dstStart, count);
- }
-
- void setRange(int start, int length, List from, [int startFrom = 0]) {
- throw const NotImplementedException();
- }
-
- void removeRange(int start, int length) {
- throw const NotImplementedException();
- }
-
- void insertRange(int start, int length, [initialValue = null]) {
- throw const NotImplementedException();
- }
-
- List getRange(int start, int length) {
- throw const NotImplementedException();
- }
-
- // Iterable<T>:
- Iterator<T> iterator() => _internal.iterator();
-
- // Collection<T>:
- Collection<T> filter(bool f(T element)) => _internal.filter(f);
- Collection map(f(T element)) => _internal.map(f);
- bool every(bool f(T element)) => _internal.every(f);
- bool some(bool f(T element)) => _internal.some(f);
- void forEach(void f(T element)) { _internal.forEach(f); }
- bool isEmpty() => length == 0;
-}
-
-// TODO(jmesserly): is this too granular? Other similar systems make whole
-// classes observable instead of individual fields. The memory cost of having
-// every field effectively boxed, plus having a listeners list is likely too
-// much. Also, making a value observable necessitates adding ".value" to lots
-// of places, and constructing all fields with the verbose
-// "new ObservableValue<DataType>(myValue)".
-/** A wrapper around a single value whose change can be observed. */
-class ObservableValue<T> extends AbstractObservable {
- ObservableValue(T value, [Observable parent = null])
- : super(parent), _value = value;
-
- T get value() => _value;
-
- void set value(T newValue) {
- // Only fire on an actual change.
- // TODO(terry): An object identity test === is needed. Each DataSource has
- // its own operator == which does a value compare. Which
- // equality check should be done?
- if (newValue !== _value) {
- final oldValue = _value;
- _value = newValue;
- recordPropertyUpdate("value", newValue, oldValue);
- }
- }
-
- T _value;
-}
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