Inspector JSON protocol to support Flutter IntelliJ Plugin tree view. (#12932)

packages/flutter/lib/src/foundation/diagnostics.dart

@@ -743,6 +743,33 @@ abstract class DiagnosticsNode {
 
   String get _separator => showSeparator ? ':' : '';
 
+  /// Serialize the node excluding its descendents to a JSON map.
+  ///
+  /// Subclasses should override if they have additional properties that are
+  /// useful for the GUI tools that consume this JSON.
+  ///
+  /// See also:
+  ///
+  ///  * [WidgetInspectorService], which forms the bridge between JSON returned
+  ///    by this method and interactive tree views in the Flutter IntelliJ
+  ///    plugin.
+  @mustCallSuper
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> data = <String, Object>{
+      'name': name,
+      'showSeparator': showSeparator,
+      'description': toDescription(),
+      'level': describeEnum(level),
+      'showName': showName,
+      'emptyBodyDescription': emptyBodyDescription,
+      'style': describeEnum(style),
+      'valueToString': value.toString(),
+      'type': runtimeType.toString(),
+      'hasChildren': getChildren().isNotEmpty,
+    };
+    return data;
+  }
+
   /// Returns a string representation of this diagnostic that is compatible with
   /// the style of the parent if the node is not the root.
   ///
@@ -1054,6 +1081,13 @@ class StringProperty extends DiagnosticsProperty<String> {
   /// Whether the value is enclosed in double quotes.
   final bool quoted;
 
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    json['quoted'] = quoted;
+    return json;
+  }
+
   @override
   String valueToString({ TextTreeConfiguration parentConfiguration }) {
     String text = _description ?? value;
@@ -1114,6 +1148,15 @@ abstract class _NumProperty<T extends num> extends DiagnosticsProperty<T> {
     level: level,
   );
 
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    if (unit != null)
+      json['unit'] = unit;
+
+    json['numberToString'] = numberToString();
+    return json;
+  }
 
   /// Optional unit the [value] is measured in.
   ///
@@ -1326,6 +1369,17 @@ class FlagProperty extends DiagnosticsProperty<bool> {
          level: level,
        );
 
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    if (ifTrue != null)
+      json['ifTrue'] = ifTrue;
+    if (ifFalse != null)
+      json['ifFalse'] = ifFalse;
+
+    return json;
+  }
+
   /// Description to use if the property [value] is true.
   ///
   /// If not specified and [value] equals true the property's priority [level]
@@ -1443,6 +1497,15 @@ class IterableProperty<T> extends DiagnosticsProperty<Iterable<T>> {
       return DiagnosticLevel.fine;
     return super.level;
   }
+
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    if (value != null) {
+      json['values'] = value.map<String>((T value) => value.toString()).toList();
+    }
+    return json;
+  }
 }
 
 /// An property than displays enum values tersely.
@@ -1581,6 +1644,14 @@ class ObjectFlagProperty<T> extends DiagnosticsProperty<T> {
 
     return super.level;
   }
+
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    if (ifPresent != null)
+      json['ifPresent'] = ifPresent;
+    return json;
+  }
 }
 
 /// Signature for computing the value of a property.
@@ -1683,6 +1754,28 @@ class DiagnosticsProperty<T> extends DiagnosticsNode {
 
   final String _description;
 
+  @override
+  Map<String, Object> toJsonMap() {
+    final Map<String, Object> json = super.toJsonMap();
+    if (defaultValue != kNoDefaultValue)
+      json['defaultValue'] = defaultValue.toString();
+    if (ifEmpty != null)
+      json['ifEmpty'] = ifEmpty;
+    if (ifNull != null)
+      json['ifNull'] = ifNull;
+    if (tooltip != null)
+      json['tooltip'] = tooltip;
+    json['missingIfNull'] = missingIfNull;
+    if (exception != null)
+      json['exception'] = exception.toString();
+    json['propertyType'] = propertyType.toString();
+    json['valueToString'] = valueToString();
+    json['defaultLevel'] = describeEnum(_defaultLevel);
+    if (T is Diagnosticable)
+      json['isDiagnosticableValue'] = true;
+    return json;
+  }
+
   /// Returns a string representation of the property value.
   ///
   /// Subclasses should override this method instead of [toDescription] to

packages/flutter/lib/src/widgets/framework.dart

@@ -3362,6 +3362,20 @@ abstract class Element extends DiagnosticableTree implements BuildContext {
     return chain.join(' \u2190 ');
   }
 
+  /// Returns the parent chain from this element back to the root of the tree.
+  ///
+  /// Useful for debug display of a tree of Elements with only nodes in the path
+  /// from the root to this Element expanded.
+  List<Element> debugGetDiagnosticChain() {
+    final List<Element> chain = <Element>[this];
+    Element node = _parent;
+    while (node != null) {
+      chain.add(node);
+      node = node._parent;
+    }
+    return chain;
+  }
+
   /// A short, textual description of this element.
   @override String toStringShort() {
     return widget != null ? '${widget.toStringShort()}' : '[$runtimeType]';