Initial commit of Effen reactive framework experiment for Sky

sky/examples/fn/lib/node.dart

Index: sky/examples/fn/lib/node.dart
diff --git a/sky/examples/fn/lib/node.dart b/sky/examples/fn/lib/node.dart
new file mode 100644
index 0000000000000000000000000000000000000000..f7ea1a301428b6fd3156f878ab8a6d139fdfa7ea
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+++ b/sky/examples/fn/lib/node.dart
@@ -0,0 +1,512 @@
+part of fn;
+
+void parentInsertBefore(sky.ParentNode parent,
+                        sky.Node node,
+                        sky.Node ref) {
+  if (ref != null) {
+    ref.insertBefore([node]);
+  } else {
+    parent.appendChild(node);
+  }
+}
+
+abstract class Node {
+  String _key = null;
+  sky.Node _root = null;
+
+  Node({ Object key }) {
+    _key = key == null ? "$runtimeType" : "$runtimeType-$key";
+  }
+
+  // Return true IFF the old node has *become* the new node (should be
+  // retained because it is stateful)
+  bool _sync(Node old, sky.ParentNode host, sky.Node insertBefore);
+
+  void _remove() {
+    assert(_root != null);
+    _root.remove();
+    _root = null;
+  }
+}
+
+class Text extends Node {
+  String data;
+
+  // Text nodes are special cases of having non-unique keys (which don't need
+  // to be assigned as part of the API). Since they are unique in not having
+  // children, there's little point to reordering, so we always just re-assign
+  // the data.
+  Text(this.data) : super(key:'*text*');
+
+  bool _sync(Node old, sky.ParentNode host, sky.Node insertBefore) {
+    if (old == null) {
+      _root = new sky.Text(data);
+      parentInsertBefore(host, _root, insertBefore);
+      return false;
+    }
+
+    _root = old._root;
+    (_root as sky.Text).data = data;
+    return false;
+  }
+}
+
+var _emptyList = new List<Node>();
+
+abstract class Element extends Node {
+
+  String get _tagName;
+
+  Element get _emptyElement;
+
+  String inlineStyle;
+
+  sky.EventListener onClick;
+  sky.EventListener onFlingCancel;
+  sky.EventListener onFlingStart;
+  sky.EventListener onGestureTap;
+  sky.EventListener onPointerCancel;
+  sky.EventListener onPointerDown;
+  sky.EventListener onPointerMove;
+  sky.EventListener onPointerUp;
+  sky.EventListener onScrollEnd;
+  sky.EventListener onScrollStart;
+  sky.EventListener onScrollUpdate;
+  sky.EventListener onWheel;
+
+  List<Node> _children = null;
+  String _className = '';
+
+  Element({
+    Object key,
+    List<Node> children,
+    Style style,
+
+    this.inlineStyle,
+
+    // Events
+    this.onClick,
+    this.onFlingCancel,
+    this.onFlingStart,
+    this.onGestureTap,
+    this.onPointerCancel,
+    this.onPointerDown,
+    this.onPointerMove,
+    this.onPointerUp,
+    this.onScrollEnd,
+    this.onScrollStart,
+    this.onScrollUpdate,
+    this.onWheel
+  }) : super(key:key) {
+
+    _className = style == null ? '': style._className;
+    _children = children == null ? _emptyList : children;
+
+    if (debugWarnings()) {
+      _debugReportDuplicateIds();
+    }
+  }
+
+  void _remove() {
+    super._remove();
+    if (_children != null) {
+      for (var child in _children) {
+        child._remove();
+      }
+    }
+    _children = null;
+  }
+
+  void _debugReportDuplicateIds() {
+    var idSet = new HashSet<String>();
+    for (var child in _children) {
+      if (child is Text) {
+        continue; // Text nodes all have the same key and are never reordered.
+      }
+
+      if (!idSet.add(child._key)) {
+        throw '''If multiple (non-Text) nodes of the same type exist as children
+                 of another node, they must have unique keys.''';
+      }
+    }
+  }
+
+  void _syncEvent(String eventName, sky.EventListener listener,
+                  sky.EventListener oldListener) {
+    sky.Element root = _root as sky.Element;
+    if (listener == oldListener)
+      return;
+
+    if (oldListener != null) {
+      root.removeEventListener(eventName, oldListener);
+    }
+
+    if (listener != null) {
+      root.addEventListener(eventName, listener);
+    }
+  }
+
+  void _syncEvents([Element old]) {
+    _syncEvent('click', onClick, old.onClick);
+    _syncEvent('gestureflingcancel', onFlingCancel, old.onFlingCancel);
+    _syncEvent('gestureflingstart', onFlingStart, old.onFlingStart);
+    _syncEvent('gesturescrollend', onScrollEnd, old.onScrollEnd);
+    _syncEvent('gesturescrollstart', onScrollStart, old.onScrollStart);
+    _syncEvent('gesturescrollupdate', onScrollUpdate, old.onScrollUpdate);
+    _syncEvent('gesturetap', onGestureTap, old.onGestureTap);
+    _syncEvent('pointercancel', onPointerCancel, old.onPointerCancel);
+    _syncEvent('pointerdown', onPointerDown, old.onPointerDown);
+    _syncEvent('pointermove', onPointerMove, old.onPointerMove);
+    _syncEvent('pointerup', onPointerUp, old.onPointerUp);
+    _syncEvent('wheel', onWheel, old.onWheel);
+  }
+
+  void _syncNode([Element old]) {
+    if (old == null) {
+      old = _emptyElement;
+    }
+
+    _syncEvents(old);
+
+    sky.Element root = _root as sky.Element;
+    if (_className != old._className) {
+      root.setAttribute('class', _className);
+    }
+
+    if (inlineStyle != old.inlineStyle) {
+      root.setAttribute('style', inlineStyle);
+    }
+  }
+
+  bool _sync(Node old, sky.ParentNode host, sky.Node insertBefore) {
+    // print("---Syncing children of $_key");
+
+    Element oldElement = old as Element;
+
+    if (oldElement == null) {
+      // print("...no oldElement, initial render");
+
+      _root = sky.document.createElement(_tagName);
+      _syncNode();
+
+      for (var child in _children) {
+        child._sync(null, _root, null);
+        assert(child._root is sky.Node);
+      }
+
+      parentInsertBefore(host, _root, insertBefore);
+      return false;
+    }
+
+    _root = oldElement._root;
+    oldElement._root = null;
+    sky.Element root = (_root as sky.Element);
+
+    _syncNode(oldElement);
+
+    var startIndex = 0;
+    var endIndex = _children.length;
+
+    var oldChildren = oldElement._children;
+    var oldStartIndex = 0;
+    var oldEndIndex = oldChildren.length;
+
+    sky.Node nextSibling = null;
+    Node currentNode = null;
+    Node oldNode = null;
+
+    void sync(int atIndex) {
+      if (currentNode._sync(oldNode, root, nextSibling)) {
+        // oldNode was stateful and must be retained.
+        assert(oldNode != null);
+        currentNode = oldNode;
+        _children[atIndex] = currentNode;
+      }
+      assert(currentNode._root is sky.Node);
+    }
+
+    // Scan backwards from end of list while nodes can be directly synced
+    // without reordering.
+    // print("...scanning backwards");
+    while (endIndex > startIndex && oldEndIndex > oldStartIndex) {
+      currentNode = _children[endIndex - 1];
+      oldNode = oldChildren[oldEndIndex - 1];
+
+      if (currentNode._key != oldNode._key) {
+        break;
+      }
+
+      // print('> syncing matched at: $endIndex : $oldEndIndex');
+      endIndex--;
+      oldEndIndex--;
+      sync(endIndex);
+      nextSibling = currentNode._root;
+    }
+
+    HashMap<String, Node> oldNodeIdMap = null;
+
+    bool oldNodeReordered(String key) {
+      return oldNodeIdMap != null &&
+             oldNodeIdMap.containsKey(key) &&
+             oldNodeIdMap[key] == null;
+    }
+
+    void advanceOldStartIndex() {
+      oldStartIndex++;
+      while (oldStartIndex < oldEndIndex &&
+             oldNodeReordered(oldChildren[oldStartIndex]._key)) {
+        oldStartIndex++;
+      }
+    }
+
+    void ensureOldIdMap() {
+      if (oldNodeIdMap != null)
+        return;
+
+      oldNodeIdMap = new HashMap<String, Node>();
+      for (int i = oldStartIndex; i < oldEndIndex; i++) {
+        var node = oldChildren[i];
+        if (node is! Text) {
+          oldNodeIdMap.putIfAbsent(node._key, () => node);
+        }
+      }
+    }
+
+    bool searchForOldNode() {
+      if (currentNode is Text)
+        return false; // Never re-order Text nodes.
+
+      ensureOldIdMap();
+      oldNode = oldNodeIdMap[currentNode._key];
+      if (oldNode == null)
+        return false;
+
+      oldNodeIdMap[currentNode._key] = null; // mark it reordered.
+      // print("Reparenting ${currentNode._key}");
+      parentInsertBefore(root, oldNode._root, nextSibling);
+      return true;
+    }
+
+    // Scan forwards, this time we may re-order;
+    // print("...scanning forward");
+    nextSibling = root.firstChild;
+    while (startIndex < endIndex && oldStartIndex < oldEndIndex) {
+      currentNode = _children[startIndex];
+      oldNode = oldChildren[oldStartIndex];
+
+      if (currentNode._key == oldNode._key) {
+        // print('> syncing matched at: $startIndex : $oldStartIndex');
+        assert(currentNode.runtimeType == oldNode.runtimeType);
+        nextSibling = nextSibling.nextSibling;
+        sync(startIndex);
+        startIndex++;
+        advanceOldStartIndex();
+        continue;
+      }
+
+      oldNode = null;
+      if (searchForOldNode()) {
+        // print('> reordered to $startIndex');
+      } else {
+        // print('> inserting at $startIndex');
+      }
+
+      sync(startIndex);
+      startIndex++;
+    }
+
+    // New insertions
+    oldNode = null;
+    // print('...processing remaining insertions');
+    while (startIndex < endIndex) {
+      // print('> inserting at $startIndex');
+      currentNode = _children[startIndex];
+      sync(startIndex);
+      startIndex++;
+    }
+
+    // Removals
+    // print('...processing remaining removals');
+    currentNode = null;
+    while (oldStartIndex < oldEndIndex) {
+      oldNode = oldChildren[oldStartIndex];
+      // print('> ${oldNode._key} removing from $oldEndIndex');
+      oldNode._remove();
+      advanceOldStartIndex();
+    }
+
+    oldElement._children = null;
+    return false;
+  }
+}
+
+class Container extends Element {
+
+  String get _tagName => 'div';
+
+  static Container _emptyContainer = new Container();
+
+  Element get _emptyElement => _emptyContainer;
+
+  Container({
+    Object key,
+    List<Node> children,
+    Style style,
+    String inlineStyle,
+    sky.EventListener onClick,
+    sky.EventListener onFlingCancel,
+    sky.EventListener onFlingStart,
+    sky.EventListener onGestureTap,
+    sky.EventListener onPointerCancel,
+    sky.EventListener onPointerDown,
+    sky.EventListener onPointerMove,
+    sky.EventListener onPointerUp,
+    sky.EventListener onScrollEnd,
+    sky.EventListener onScrollStart,
+    sky.EventListener onScrollUpdate,
+    sky.EventListener onWheel
+  }) : super(
+    key: key,
+    children: children,
+    style: style,
+    inlineStyle: inlineStyle,
+    onClick: onClick,
+    onFlingCancel: onFlingCancel,
+    onFlingStart: onFlingStart,
+    onGestureTap: onGestureTap,
+    onPointerCancel: onPointerCancel,
+    onPointerDown: onPointerDown,
+    onPointerMove: onPointerMove,
+    onPointerUp: onPointerUp,
+    onScrollEnd: onScrollEnd,
+    onScrollStart: onScrollStart,
+    onScrollUpdate: onScrollUpdate,
+    onWheel: onWheel
+  );
+}
+
+class Image extends Element {
+
+  String get _tagName => 'img';
+
+  static Image _emptyImage = new Image();
+  Element get _emptyElement => _emptyImage;
+
+  String src;
+  int width;
+  int height;
+
+  Image({
+    Object key,
+    List<Node> children,
+    Style style,
+    String inlineStyle,
+    sky.EventListener onClick,
+    sky.EventListener onFlingCancel,
+    sky.EventListener onFlingStart,
+    sky.EventListener onGestureTap,
+    sky.EventListener onPointerCancel,
+    sky.EventListener onPointerDown,
+    sky.EventListener onPointerMove,
+    sky.EventListener onPointerUp,
+    sky.EventListener onScrollEnd,
+    sky.EventListener onScrollStart,
+    sky.EventListener onScrollUpdate,
+    sky.EventListener onWheel,
+    this.width,
+    this.height,
+    this.src
+  }) : super(
+    key: key,
+    children: children,
+    style: style,
+    inlineStyle: inlineStyle,
+    onClick: onClick,
+    onFlingCancel: onFlingCancel,
+    onFlingStart: onFlingStart,
+    onGestureTap: onGestureTap,
+    onPointerCancel: onPointerCancel,
+    onPointerDown: onPointerDown,
+    onPointerMove: onPointerMove,
+    onPointerUp: onPointerUp,
+    onScrollEnd: onScrollEnd,
+    onScrollStart: onScrollStart,
+    onScrollUpdate: onScrollUpdate,
+    onWheel: onWheel
+  );
+
+  void _syncNode([Element old]) {
+    super._syncNode(old);
+
+    Image oldImage = old != null ? old : _emptyImage;
+    sky.HTMLImageElement skyImage = _root as sky.HTMLImageElement;
+    if (src != oldImage.src) {
+      skyImage.src = src;
+    }
+
+    if (width != oldImage.width) {
+      skyImage.style['width'] = '${width}px';
+    }
+    if (height != oldImage.height) {
+      skyImage.style['height'] = '${height}px';
+    }
+  }
+}
+
+class Anchor extends Element {
+
+  String get _tagName => 'a';
+
+  static Anchor _emptyAnchor = new Anchor();
+
+  String href;
+
+  Anchor({
+    Object key,
+    List<Node> children,
+    Style style,
+    String inlineStyle,
+    sky.EventListener onClick,
+    sky.EventListener onFlingCancel,
+    sky.EventListener onFlingStart,
+    sky.EventListener onGestureTap,
+    sky.EventListener onPointerCancel,
+    sky.EventListener onPointerDown,
+    sky.EventListener onPointerMove,
+    sky.EventListener onPointerUp,
+    sky.EventListener onScrollEnd,
+    sky.EventListener onScrollStart,
+    sky.EventListener onScrollUpdate,
+    sky.EventListener onWheel,
+    this.width,
+    this.height,
+    this.href
+  }) : super(
+    key: key,
+    children: children,
+    style: style,
+    inlineStyle: inlineStyle,
+    onClick: onClick,
+    onFlingCancel: onFlingCancel,
+    onFlingStart: onFlingStart,
+    onGestureTap: onGestureTap,
+    onPointerCancel: onPointerCancel,
+    onPointerDown: onPointerDown,
+    onPointerMove: onPointerMove,
+    onPointerUp: onPointerUp,
+    onScrollEnd: onScrollEnd,
+    onScrollStart: onScrollStart,
+    onScrollUpdate: onScrollUpdate,
+    onWheel: onWheel
+  );
+
+  void _syncNode([Element old]) {
+    Anchor oldAnchor = old != null ? old as Anchor : _emptyAnchor;
+    super._syncNode(oldAnchor);
+
+    sky.HTMLAnchorElement skyAnchor = _root as sky.HTMLAnchorElement;
+    if (href != oldAnchor.href) {
+      skyAnchor.href = href;
+    }
+  }
+}