Merge pull request #1653 from Hixie/debugging

Sundry debugging aids and fixes

packages/flutter/lib/rendering.dart

@@ -7,6 +7,7 @@ library rendering;
 
 export 'src/rendering/auto_layout.dart';
 export 'src/rendering/basic_types.dart';
+export 'src/rendering/binding.dart';
 export 'src/rendering/block.dart';
 export 'src/rendering/box.dart';
 export 'src/rendering/debug.dart';
@@ -22,7 +23,6 @@ export 'src/rendering/object.dart';
 export 'src/rendering/paragraph.dart';
 export 'src/rendering/proxy_box.dart';
 export 'src/rendering/shifted_box.dart';
-export 'src/rendering/binding.dart';
 export 'src/rendering/stack.dart';
 export 'src/rendering/statistics_box.dart';
 export 'src/rendering/toggleable.dart';

packages/flutter/lib/src/animation/performance.dart

@@ -31,6 +31,8 @@ typedef void PerformanceStatusListener(PerformanceStatus status);
 /// want to watch a performance but should not be able to change the
 /// performance's state.
 abstract class PerformanceView {
+  const PerformanceView();
+
   /// Update the given variable according to the current progress of the performance
   void updateVariable(Animatable variable);
   /// Calls the listener every time the progress of the performance changes
@@ -45,6 +47,10 @@ abstract class PerformanceView {
   /// The current status of this animation
   PerformanceStatus get status;
 
+  /// The current progress of this animation (a value from 0.0 to 1.0).
+  /// This is the value that is used to update any variables when using updateVariable().
+  double get progress;
+
   /// Whether this animation is stopped at the beginning
   bool get isDismissed => status == PerformanceStatus.dismissed;
 
@@ -61,12 +67,16 @@ abstract class PerformanceView {
 /// [fling] the timeline causing a physics-based simulation to take over the
 /// progression.
 class Performance extends PerformanceView {
-  Performance({ this.duration, double progress }) {
+  Performance({ this.duration, double progress, this.debugLabel }) {
     _timeline = new SimulationStepper(_tick);
     if (progress != null)
       _timeline.value = progress.clamp(0.0, 1.0);
   }
 
+  /// A label that is used in the toString() output. Intended to aid with
+  /// identifying performance instances in debug output.
+  final String debugLabel;
+
   /// Returns a [PerformanceView] for this performance,
   /// so that a pointer to this object can be passed around without
   /// allowing users of that pointer to mutate the AnimationPerformance state.
@@ -220,6 +230,12 @@ class Performance extends PerformanceView {
     _notifyListeners();
     _checkStatusChanged();
   }
+
+  String toString() {
+    if (debugLabel != null)
+      return '$runtimeType at $progress for $debugLabel';
+    return '$runtimeType at $progress';
+  }
 }
 
 /// An animation performance with an animated variable with a concrete type

packages/flutter/lib/src/material/drawer.dart

@@ -106,7 +106,7 @@ class _DrawerRoute extends Route {
   final int level;
 
   PerformanceView get performance => _performance?.view;
-  Performance _performance = new Performance(duration: _kBaseSettleDuration);
+  Performance _performance = new Performance(duration: _kBaseSettleDuration, debugLabel: 'Drawer');
 
   bool get opaque => false;
 

packages/flutter/lib/src/rendering/binding.dart

@@ -6,6 +6,7 @@ import 'dart:ui' as ui;
 
 import 'package:flutter/animation.dart';
 import 'package:flutter/gestures.dart';
+import 'package:flutter/rendering.dart';
 
 import 'box.dart';
 import 'hit_test.dart';
@@ -252,5 +253,5 @@ class FlutterBinding extends HitTestTarget {
 
 /// Prints a textual representation of the entire render tree
 void debugDumpRenderTree() {
-  FlutterBinding.instance.renderView.toStringDeep().split('\n').forEach(print);
+  debugPrint(FlutterBinding.instance.renderView.toStringDeep());
 }

packages/flutter/lib/src/rendering/box.dart

@@ -359,9 +359,11 @@ abstract class RenderBox extends RenderObject {
         final _DebugSize _size = this._size;
         assert(_size._owner == this);
         if (RenderObject.debugActiveLayout != null) {
-          // we are always allowed to access our own size (for print debugging and asserts if nothing else)
-          // other than us, the only object that's allowed to read our size is our parent, if they're said they will
-          // if you hit this assert trying to access a child's size, pass parentUsesSize: true in layout()
+          // We are always allowed to access our own size (for print debugging
+          // and asserts if nothing else). Other than us, the only object that's
+          // allowed to read our size is our parent, if they've said they will.
+          // If you hit this assert trying to access a child's size, pass
+          // "parentUsesSize: true" to that child's layout().
           assert(debugDoingThisResize || debugDoingThisLayout ||
                  (RenderObject.debugActiveLayout == parent && _size._canBeUsedByParent));
         }
@@ -377,8 +379,12 @@ abstract class RenderBox extends RenderObject {
     assert((sizedByParent && debugDoingThisResize) ||
            (!sizedByParent && debugDoingThisLayout));
     assert(() {
-      if (value is _DebugSize)
-        return value._canBeUsedByParent && value._owner.parent == this;
+      if (value is _DebugSize) {
+        if (value._owner != this) {
+          assert(value._owner.parent == this);
+          assert(value._canBeUsedByParent);
+        }
+      }
       return true;
     });
     _size = value;
@@ -389,6 +395,11 @@ abstract class RenderBox extends RenderObject {
     assert(debugDoesMeetConstraints());
   }
 
+  void debugResetSize() {
+    // updates the value of size._canBeUsedByParent if necessary
+    size = size;
+  }
+
   Map<TextBaseline, double> _cachedBaselines;
   bool _ancestorUsesBaseline = false;
   static bool _debugDoingBaseline = false;
@@ -473,7 +484,7 @@ abstract class RenderBox extends RenderObject {
     });
     bool result = constraints.isSatisfiedBy(_size);
     if (!result)
-      print("${this.runtimeType} does not meet its constraints. Constraints: $constraints, size: $_size");
+      debugPrint("${this.runtimeType} does not meet its constraints. Constraints: $constraints, size: $_size");
     return result;
   }
 

packages/flutter/lib/src/rendering/debug.dart

@@ -3,6 +3,8 @@
 // found in the LICENSE file.
 
 import 'dart:ui' as ui;
+import 'dart:async';
+import 'dart:collection';
 
 /// Causes each RenderBox to paint a box around its bounds.
 bool debugPaintSizeEnabled = false;
@@ -30,3 +32,34 @@ bool debugPaintBoundsEnabled = false;
 
 /// The color to use when painting RenderError boxes in checked mode.
 ui.Color debugErrorBoxColor = const ui.Color(0xFFFF0000);
+
+/// Prints a message to the console, which you can access using the "flutter"
+/// tool's "logs" command ("flutter logs").
+///
+/// This function very crudely attempts to throttle the rate at which messages
+/// are sent to avoid data loss on Android. This means that interleaving calls
+/// to this function (directly or indirectly via [debugDumpRenderTree] or
+/// [debugDumpApp]) and to the Dart [print] method can result in out-of-order
+/// messages in the logs.
+void debugPrint(String message) {
+  _debugPrintBuffer.addAll(message.split('\n'));
+  if (!_debugPrintScheduled)
+    _debugPrintTask();
+}
+int _debugPrintedCharacters = 0;
+int _kDebugPrintCapacity = 32 * 1024;
+Queue<String> _debugPrintBuffer = new Queue<String>();
+bool _debugPrintScheduled = false;
+void _debugPrintTask() {
+  _debugPrintScheduled = false;
+  while (_debugPrintedCharacters < _kDebugPrintCapacity && _debugPrintBuffer.length > 0) {
+    String line = _debugPrintBuffer.removeFirst();
+    _debugPrintedCharacters += line.length; // TODO(ianh): Use the UTF-8 byte length instead
+    print(line);
+  }
+  if (_debugPrintBuffer.length > 0) {
+    _debugPrintScheduled = true;
+    _debugPrintedCharacters = 0;
+    new Timer(new Duration(seconds: 1), _debugPrintTask);
+  }
+}

packages/flutter/lib/src/rendering/object.dart

@@ -513,14 +513,14 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
 
   dynamic debugExceptionContext = '';
   void _debugReportException(String method, dynamic exception, StackTrace stack) {
-    print('-- EXCEPTION --');
-    print('The following exception was raised during $method():');
-    print('$exception');
-    print('Stack trace:');
-    print('$stack');
-    print('The following RenderObject was being processed when the exception was fired:\n${this}');
+    debugPrint('-- EXCEPTION --');
+    debugPrint('The following exception was raised during $method():');
+    debugPrint('$exception');
+    debugPrint('Stack trace:');
+    debugPrint('$stack');
+    debugPrint('The following RenderObject was being processed when the exception was fired:\n${this}');
     if (debugExceptionContext != '')
-      'That RenderObject had the following exception context:\n$debugExceptionContext'.split('\n').forEach(print);
+      debugPrint('That RenderObject had the following exception context:\n$debugExceptionContext');
     if (debugRenderingExceptionHandler != null)
       debugRenderingExceptionHandler(this, method, exception, stack);
   }
@@ -723,15 +723,30 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
     else
       relayoutSubtreeRoot = parent._relayoutSubtreeRoot;
     assert(parent == this.parent);
-    if (!needsLayout && constraints == _constraints && relayoutSubtreeRoot == _relayoutSubtreeRoot)
+    assert(() {
+      _debugCanParentUseSize = parentUsesSize;
+      return true;
+    });
+    if (!needsLayout && constraints == _constraints && relayoutSubtreeRoot == _relayoutSubtreeRoot) {
+      assert(() {
+        // in case parentUsesSize changed since the last invocation, set size
+        // to itself, so it has the right internal debug values.
+        _debugDoingThisLayout = true;
+        RenderObject debugPreviousActiveLayout = _debugActiveLayout;
+        _debugActiveLayout = this;
+        debugResetSize();
+        _debugActiveLayout = debugPreviousActiveLayout;
+        _debugDoingThisLayout = false;
+        return true;
+      });
       return;
+    }
     _constraints = constraints;
     _relayoutSubtreeRoot = relayoutSubtreeRoot;
     assert(!_debugMutationsLocked);
     assert(!_doingThisLayoutWithCallback);
     assert(() {
       _debugMutationsLocked = true;
-      _debugCanParentUseSize = parentUsesSize;
       return true;
     });
     if (sizedByParent) {
@@ -768,6 +783,14 @@ abstract class RenderObject extends AbstractNode implements HitTestTarget {
     assert(parent == this.parent);
   }
 
+  /// If a subclass has a "size" (the state controlled by "parentUsesSize",
+  /// whatever it is in the subclass, e.g. the actual "size" property of
+  /// RenderBox), and the subclass verifies that in checked mode this "size"
+  /// property isn't used when debugCanParentUseSize isn't set, then that
+  /// subclass should override debugResetSize() to reapply the current values of
+  /// debugCanParentUseSize to that state.
+  void debugResetSize() { }
+
   /// Whether the constraints are the only input to the sizing algorithm (in
   /// particular, child nodes have no impact)
   ///

packages/flutter/lib/src/rendering/proxy_box.dart

@@ -1018,7 +1018,7 @@ class RenderTransform extends RenderProxyBox {
   String debugDescribeSettings(String prefix) {
     List<String> result = _transform.toString().split('\n').map((String s) => '$prefix  $s\n').toList();
     result.removeLast();
-    return '${super.debugDescribeSettings(prefix)}${prefix}transform matrix:\n${result.join()}\n${prefix}origin: $origin\nalignment: $alignment\n';
+    return '${super.debugDescribeSettings(prefix)}${prefix}transform matrix:\n${result.join()}\n${prefix}origin: $origin\n${prefix}alignment: $alignment\n';
   }
 }
 

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

@@ -76,6 +76,11 @@ class Opacity extends OneChildRenderObjectWidget {
   void updateRenderObject(RenderOpacity renderObject, Opacity oldWidget) {
     renderObject.opacity = opacity;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    description.add('opacity: $opacity');
+  }
 }
 
 class ColorFilter extends OneChildRenderObjectWidget {
@@ -283,6 +288,14 @@ class SizedBox extends OneChildRenderObjectWidget {
   void updateRenderObject(RenderConstrainedBox renderObject, SizedBox oldWidget) {
     renderObject.additionalConstraints = _additionalConstraints;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    if (width != null)
+      description.add('width: $width');
+    if (height != null)
+      description.add('height: $height');
+  }
 }
 
 class ConstrainedBox extends OneChildRenderObjectWidget {
@@ -298,6 +311,11 @@ class ConstrainedBox extends OneChildRenderObjectWidget {
   void updateRenderObject(RenderConstrainedBox renderObject, ConstrainedBox oldWidget) {
     renderObject.additionalConstraints = constraints;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    description.add('constraints: $constraints');
+  }
 }
 
 class FractionallySizedBox extends OneChildRenderObjectWidget {
@@ -316,6 +334,14 @@ class FractionallySizedBox extends OneChildRenderObjectWidget {
     renderObject.widthFactor = width;
     renderObject.heightFactor = height;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    if (width != null)
+      description.add('width: $width');
+    if (height != null)
+      description.add('height: $height');
+  }
 }
 
 class OverflowBox extends OneChildRenderObjectWidget {
@@ -355,6 +381,11 @@ class AspectRatio extends OneChildRenderObjectWidget {
   void updateRenderObject(RenderAspectRatio renderObject, AspectRatio oldWidget) {
     renderObject.aspectRatio = aspectRatio;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    description.add('aspectRatio: $aspectRatio');
+  }
 }
 
 class IntrinsicWidth extends OneChildRenderObjectWidget {
@@ -644,6 +675,18 @@ class Positioned extends ParentDataWidget {
     if (needsLayout)
       renderObject.markNeedsLayout();
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    if (left != null)
+      description.add('left: $left');
+    if (top != null)
+      description.add('top: $top');
+    if (right != null)
+      description.add('right: $right');
+    if (bottom != null)
+      description.add('bottom: $bottom');
+  }
 }
 
 class Grid extends MultiChildRenderObjectWidget {
@@ -728,6 +771,11 @@ class Flexible extends ParentDataWidget {
       renderObject.markNeedsLayout();
     }
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    description.add('flex: $flex');
+  }
 }
 
 class Paragraph extends LeafRenderObjectWidget {
@@ -1077,6 +1125,11 @@ class MetaData extends OneChildRenderObjectWidget {
   void updateRenderObject(RenderMetaData renderObject, MetaData oldWidget) {
     renderObject.metaData = metaData;
   }
+
+  void debugFillDescription(List<String> description) {
+    super.debugFillDescription(description);
+    description.add('$metaData');
+  }
 }
 
 class KeyedSubtree extends StatelessComponent {

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

@@ -94,8 +94,8 @@ void debugDumpApp() {
   assert(WidgetFlutterBinding.instance.renderViewElement != null);
   String mode = 'RELEASE MODE';
   assert(() { mode = 'CHECKED MODE'; return true; });
-  print('${WidgetFlutterBinding.instance.runtimeType} - $mode');
-  WidgetFlutterBinding.instance.renderViewElement.toStringDeep().split('\n').forEach(print);
+  debugPrint('${WidgetFlutterBinding.instance.runtimeType} - $mode');
+  debugPrint(WidgetFlutterBinding.instance.renderViewElement.toStringDeep());
 }
 
 /// This class provides a bridge from a RenderObject to an Element tree. The

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

@@ -7,6 +7,8 @@ import 'dart:collection';
 
 import 'package:flutter/rendering.dart';
 
+export 'package:flutter/rendering.dart' show debugPrint;
+
 // KEYS
 
 /// A Key is an identifier for [Widget]s and [Element]s. A new Widget will only
@@ -184,7 +186,7 @@ class GlobalObjectKey extends GlobalKey {
     return identical(value, typedOther.value);
   }
   int get hashCode => identityHashCode(value);
-  String toString() => '[GlobalKey ${value.runtimeType}(${value.hashCode})]';
+  String toString() => '[$runtimeType ${value.runtimeType}(${value.hashCode})]';
 }
 
 
@@ -823,10 +825,13 @@ abstract class Element<T extends Widget> implements BuildContext {
   void debugFillDescription(List<String> description) {
     if (depth == null)
       description.add('no depth');
-    if (widget == null)
+    if (widget == null) {
       description.add('no widget');
-    else
+    } else {
+      if (widget.key != null)
+        description.add('${widget.key}');
       widget.debugFillDescription(description);
+    }
   }
 
   String toStringDeep([String prefixLineOne = '', String prefixOtherLines = '']) {
@@ -1090,7 +1095,7 @@ class StatefulComponentElement<T extends StatefulComponent, U extends State<T>>
     assert(() {
       if (_state._debugLifecycleState == _StateLifecycle.initialized)
         return true;
-      print('${_state.runtimeType}.initState failed to call super.initState');
+      debugPrint('${_state.runtimeType}.initState failed to call super.initState');
       return false;
     });
     assert(() { _state._debugLifecycleState = _StateLifecycle.ready; return true; });
@@ -1123,7 +1128,7 @@ class StatefulComponentElement<T extends StatefulComponent, U extends State<T>>
     assert(() {
       if (_state._debugLifecycleState == _StateLifecycle.defunct)
         return true;
-      print('${_state.runtimeType}.dispose failed to call super.dispose');
+      debugPrint('${_state.runtimeType}.dispose failed to call super.dispose');
       return false;
     });
     assert(!dirty); // See BuildableElement.unmount for why this is important.
@@ -1267,7 +1272,7 @@ abstract class RenderObjectElement<T extends RenderObjectWidget> extends Buildab
     // dirty, e.g. if they have a builder callback. (Builder callbacks have a
     // 'BuildContext' argument which you can pass to Theme.of() and other
     // InheritedWidget APIs which eventually trigger a rebuild.)
-    print('$runtimeType failed to implement reinvokeBuilders(), but got marked dirty');
+    debugPrint('$runtimeType failed to implement reinvokeBuilders(), but got marked dirty');
     assert(() {
       'reinvokeBuilders() not implemented';
       return false;
@@ -1609,11 +1614,11 @@ void _debugReportException(String context, dynamic exception, StackTrace stack)
   if (debugWidgetsExceptionHandler != null) {
     debugWidgetsExceptionHandler(context, exception, stack);
   } else {
-    print('------------------------------------------------------------------------');
-    'Exception caught while $context'.split('\n').forEach(print);
-    print('$exception');
-    print('Stack trace:');
-    '$stack'.split('\n').forEach(print);
-    print('------------------------------------------------------------------------');
+    debugPrint('------------------------------------------------------------------------');
+    debugPrint('Exception caught while $context');
+    debugPrint('$exception');
+    debugPrint('Stack trace:');
+    debugPrint('$stack');
+    debugPrint('------------------------------------------------------------------------');
   }
 }

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

@@ -333,7 +333,7 @@ class _MixedViewportElement extends RenderObjectElement<MixedViewport> {
     double newExtent = _getElementExtent(element, innerConstraints);
     bool result = _childExtents[index] == newExtent;
     if (!result)
-      print("Element $element at index $index was size ${_childExtents[index]} but is now size $newExtent yet no invalidate() was received to that effect");
+      debugPrint("Element $element at index $index was size ${_childExtents[index]} but is now size $newExtent yet no invalidate() was received to that effect");
     return result;
   }
 

packages/unit/test/widget/drawer_test.dart

@@ -14,7 +14,7 @@ void main() {
           routes: <String, RouteBuilder>{
             '/': (RouteArguments args) {
               navigator = args.navigator;
-              new Container();
+              return new Container();
             }
           }
         )
@@ -43,7 +43,7 @@ void main() {
           routes: <String, RouteBuilder>{
             '/': (RouteArguments args) {
               navigator = args.navigator;
-              new Container();
+              return new Container();
             }
           }
         )