Verify that callers correctly set parentUsesSize if they use the child's size (and fix a few cases …

sky/sdk/lib/framework/rendering/box.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:math' as math;
 import 'dart:sky' as sky;
+
+import 'package:sky/framework/net/image_cache.dart' as image_cache;
+import 'package:vector_math/vector_math.dart';
+
+import '../debug/utils.dart';
+import '../painting/box_painter.dart';
 import 'object.dart';
-import '../painting/box_painter.dart';
-import 'package:vector_math/vector_math.dart';
-import 'package:sky/framework/net/image_cache.dart' as image_cache;
 
 export '../painting/box_painter.dart';
 
 // GENERIC BOX RENDERING
 // Anything that has a concept of x, y, width, height is going to derive from this
 
+// This class should only be used in debug builds
+class _DebugSize extends Size {
+  _DebugSize(Size source, this._owner, this._canBeUsedByParent): super.copy(source);
+  final RenderBox _owner;
+  final bool _canBeUsedByParent;
+}
+
 class EdgeDims {
   // used for e.g. padding
   const EdgeDims(this.top, this.right, this.bottom, this.left);
   const EdgeDims.all(double value)
       : top = value, right = value, bottom = value, left = value;
   const EdgeDims.only({ this.top: 0.0,
                         this.right: 0.0,
                         this.bottom: 0.0,
                         this.left: 0.0 });
   const EdgeDims.symmetric({ double vertical: 0.0,
@@ skipping 119 matching lines @@
 
   double constrainWidth(double width) {
     return clamp(min: minWidth, max: maxWidth, value: width);
   }
 
   double constrainHeight(double height) {
     return clamp(min: minHeight, max: maxHeight, value: height);
   }
 
   Size constrain(Size size) {
-    return new Size(constrainWidth(size.width), constrainHeight(size.height));
+    Size result = new Size(constrainWidth(size.width), constrainHeight(size.height));
+    if (size is _DebugSize)
+      result = new _DebugSize(result, size._owner, size._canBeUsedByParent);
+    return result;
   }
 
   bool get isInfinite => maxWidth >= double.INFINITY || maxHeight >= double.INFINITY;
 
   int get hashCode {
     int value = 373;
     value = 37 * value + minWidth.hashCode;
     value = 37 * value + maxWidth.hashCode;
     value = 37 * value + minHeight.hashCode;
     value = 37 * value + maxHeight.hashCode;
@@ skipping 46 matching lines @@
 
   // getMaxIntrinsicHeight should return the smallest height beyond which
   // increasing the height never decreases the width.
   // If the layout algorithm used is width-in-height-out, i.e. the height
   // depends on the width and not vice versa, then this will return the same
   // as getMinIntrinsicHeight().
   double getMaxIntrinsicHeight(BoxConstraints constraints) {
     return constraints.constrainHeight(0.0);
   }
 
+  // This whole block should only be here in debug builds
+  bool _debugDoingThisLayout = false;
+  bool _debugCanParentUseSize;
+  void layoutWithoutResize() {
+    _debugDoingThisLayout = true;
+    _debugCanParentUseSize = false;
+    super.layoutWithoutResize();
+    _debugCanParentUseSize = null;
+    _debugDoingThisLayout = false;
+  }
+  void layout(dynamic constraints, { bool parentUsesSize: false }) {
+    _debugDoingThisLayout = true;
+    _debugCanParentUseSize = parentUsesSize;
+    super.layout(constraints, parentUsesSize: parentUsesSize);
+    _debugCanParentUseSize = null;
+    _debugDoingThisLayout = false;
+  }
+
   BoxConstraints get constraints { BoxConstraints result = super.constraints; return result; }
   void performResize() {
     // default behaviour for subclasses that have sizedByParent = true
     size = constraints.constrain(Size.zero);
     assert(size.height < double.INFINITY);
     assert(size.width < double.INFINITY);
   }
   void performLayout() {
     // descendants have to either override performLayout() to set both
     // width and height and lay out children, or, set sizedByParent to
     // true so that performResize()'s logic above does its thing.
     assert(sizedByParent);
   }
 
   bool hitTest(HitTestResult result, { Point position }) {
     hitTestChildren(result, position: position);
     result.add(new BoxHitTestEntry(this, position));
     return true;
   }
   void hitTestChildren(HitTestResult result, { Point position }) { }
 
+  // TODO(ianh): In non-debug builds, this should all just be:
+  // Size size = Size.zero;
+  // In debug builds, however:
   Size _size = Size.zero;
   Size get size => _size;
   void set size(Size value) {
     assert(RenderObject.debugDoingLayout);
-    _size = value;
+    assert(_debugDoingThisLayout);
+    if (value is _DebugSize) {
+      assert(value._canBeUsedByParent);
+      assert(value._owner.parent == this);
+    }
+    _size = inDebugBuild ? new _DebugSize(value, this, _debugCanParentUseSize) : value;
   }
 
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}size: ${size}\n';
 }
 
 class RenderProxyBox extends RenderBox with RenderObjectWithChildMixin<RenderBox> {
 
   // ProxyBox assumes the child will be at 0,0 and will have the same size
 
   RenderProxyBox([RenderBox child = null]) {
@@ skipping 128 matching lines @@
   }
 
   double getMaxIntrinsicHeight(BoxConstraints constraints) {
     if (child != null)
       return child.getMaxIntrinsicHeight(constraints.apply(_additionalConstraints));
     return constraints.constrainHeight(0.0);
   }
 
   void performLayout() {
     if (child != null) {
-      child.layout(constraints.apply(_additionalConstraints));
+      child.layout(constraints.apply(_additionalConstraints), parentUsesSize: true);
       size = child.size;
     } else {
       performResize();
     }
   }
 
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}additionalConstraints: ${additionalConstraints}\n';
 }
 
 class RenderShrinkWrapWidth extends RenderProxyBox {
@@ skipping 24 matching lines @@
   }
 
   double getMaxIntrinsicHeight(BoxConstraints constraints) {
     if (child != null)
       return child.getMaxIntrinsicHeight(_getInnerConstraints(constraints));
     return constraints.constrainWidth(0.0);
   }
 
   void performLayout() {
     if (child != null) {
-      child.layout(_getInnerConstraints(constraints));
+      child.layout(_getInnerConstraints(constraints), parentUsesSize: true);
       size = child.size;
     } else {
       performResize();
     }
   }
 }
 
 class RenderOpacity extends RenderProxyBox {
   RenderOpacity({ RenderBox child, double opacity })
     : this._opacity = opacity, super(child) {
@@ skipping 203 matching lines @@
   }
 
   double getMaxIntrinsicHeight(BoxConstraints constraints) {
     if (child != null)
       return child.getMaxIntrinsicHeight(constraints);
     return super.getMaxIntrinsicHeight(constraints);
   }
 
   void performLayout() {
     if (child != null) {
-      child.layout(constraints.loosen());
+      child.layout(constraints.loosen(), parentUsesSize: true);
       size = constraints.constrain(child.size);
       assert(child.parentData is BoxParentData);
       Size delta = size - child.size;
       child.parentData.position = new Point(delta.width * horizontal, delta.height * vertical);
     } else {
       performResize();
     }
   }
 
   String debugDescribeSettings(String prefix) => '${super.debugDescribeSettings(prefix)}${prefix}horizontal: ${horizontal}\n${prefix}vertical: ${vertical}\n';
@@ skipping 362 matching lines @@
 
   void defaultPaint(RenderObjectDisplayList canvas) {
     RenderBox child = firstChild;
     while (child != null) {
       assert(child.parentData is ParentDataType);
       canvas.paintChild(child, child.parentData.position);
       child = child.parentData.nextSibling;
     }
   }
 }