Index: pkg/template_binding/lib/src/node_binding.dart |
diff --git a/pkg/template_binding/lib/src/node_binding.dart b/pkg/template_binding/lib/src/node_binding.dart |
new file mode 100644 |
index 0000000000000000000000000000000000000000..95c5e00dd5ee999e2fca097f21cc17171252498a |
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+++ b/pkg/template_binding/lib/src/node_binding.dart |
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+// Copyright (c) 2013, 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 template_binding.src.node_binding; |
+ |
+import 'dart:async' show StreamSubscription; |
+import 'dart:html' show Node; |
+import 'package:observe/observe.dart' show PathObserver, CompoundPathObserver; |
+ |
+/** Test only method. Not re-exported. */ |
+getObserverForTest(NodeBinding binding) => binding._observer; |
+ |
+/** |
+ * A data binding on a [Node]. |
+ * See [NodeBindExtension.bindings] and [NodeBindExtension.bind]. |
+ */ |
+abstract class NodeBinding { |
+ Node _node; |
+ var _model; |
+ |
+ // TODO(jmesserly): need common interface for PathObserver, |
+ // CompoundPathObserver. |
+ var _observer; |
+ StreamSubscription _pathSub; |
+ |
+ /** The property of [node] which will be data bound. */ |
+ final String property; |
+ |
+ /** The property of [node] which will be data bound. */ |
+ final String path; |
+ |
+ /** The node that has [property] which will be data bound. */ |
+ Node get node => _node; |
+ |
+ /** The bound data model. */ |
+ get model => _model; |
+ |
+ /** True if this binding has been [closed]. */ |
+ bool get closed => _node == null; |
+ |
+ /** The value at the [path] on [model]. */ |
+ get value => _observer.value; |
+ |
+ set value(newValue) { |
+ _observer.value = newValue; |
+ } |
+ |
+ NodeBinding(this._node, this.property, this._model, [String path]) |
+ : path = path != null ? path : '' { |
+ |
+ // Fast path if we're observing "value" |
+ if ((model is PathObserver || model is CompoundPathObserver) && |
+ path == 'value') { |
+ |
+ _observer = model; |
+ } else { |
+ // Create the path observer |
+ _observer = new PathObserver(model, this.path); |
+ } |
+ |
+ _pathSub = _observer.changes.listen((r) => valueChanged(value)); |
+ valueChanged(value); |
+ } |
+ |
+ /** Called when [value] changes to update the [node]. */ |
+ // TODO(jmesserly): the impl in template_binding uses reflection to set the |
+ // property, but that isn't used except for specific known fields like |
+ // "textContent", so I'm overridding this in the subclasses instead. |
+ void valueChanged(newValue); |
+ |
+ /** Called to sanitize the value before it is assigned into the property. */ |
+ sanitizeBoundValue(value) => value == null ? '' : '$value'; |
+ |
+ /** |
+ * Called by [NodeBindExtension.unbind] to close this binding and unobserve |
+ * the [path]. |
+ * |
+ * This can be overridden in subclasses, but they must call `super.close()` |
+ * to free associated resources. They must also check [closed] and return |
+ * immediately if already closed. |
+ */ |
+ void close() { |
+ if (closed) return; |
+ |
+ if (_pathSub != null) _pathSub.cancel(); |
+ _pathSub = null; |
+ _observer = null; |
+ _node = null; |
+ _model = null; |
+ } |
+} |