[CSS Shapes] inset args and radial args should serialize to the simplest form

Source/core/css/CSSBasicShapes.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1. Redistributions of source code must retain the above
  *    copyright notice, this list of conditions and the following
  *    disclaimer.
@@ skipping 278 matching lines @@
     const String& topRightRadiusWidth, const String& topRightRadiusHeight,
     const String& bottomRightRadiusWidth, const String& bottomRightRadiusHeight,
     const String& bottomLeftRadiusWidth, const String& bottomLeftRadiusHeight)
 {
     char opening[] = "inset(";
     char separator[] = " ";
     char cornersSeparator[] = "round";
     StringBuilder result;
     result.appendLiteral(opening);
     result.append(top);
-    if (!right.isNull()) {
+    bool showLeftArg = !left.isNull() && left != right;
+    bool showBottomArg = !bottom.isNull() && (bottom != top || showLeftArg);
+    bool showRightArg = !right.isNull() && (right != top || showBottomArg);
+    if (showRightArg) {
         result.appendLiteral(separator);
         result.append(right);
     }
-    if (!bottom.isNull()) {
+    if (showBottomArg) {
         result.appendLiteral(separator);
         result.append(bottom);
     }
-    if (!left.isNull()) {
+    if (showLeftArg) {
         result.appendLiteral(separator);
         result.append(left);
     }
 
     if (!topLeftRadiusWidth.isNull() && !topLeftRadiusHeight.isNull()) {
-        result.appendLiteral(separator);
-        result.appendLiteral(cornersSeparator);
-        result.appendLiteral(separator);
+        bool showHorizontalBottomLeft = topRightRadiusWidth != bottomLeftRadiusWidth;
+        bool showHorizontalBottomRight = showHorizontalBottomLeft || (bottomRightRadiusWidth != topLeftRadiusWidth);
+        bool showHorizontalTopRight = showHorizontalBottomRight || (topRightRadiusWidth != topLeftRadiusWidth);
 
-        result.append(topLeftRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(topRightRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(bottomRightRadiusWidth);
-        result.appendLiteral(separator);
-        result.append(bottomLeftRadiusWidth);
+        Vector<String> horizontalRadii;

[Bear Travis, 2014/04/08 19:08:35]

Would it be possible / worth it to factor out the horizontalRadii and
verticalRadii building into a helper method that calculates the booleans and
adds the requisite strings to the vector?

+        horizontalRadii.append(topLeftRadiusWidth);
+        if (showHorizontalTopRight)
+            horizontalRadii.append(topRightRadiusWidth);
+        if (showHorizontalBottomRight)
+            horizontalRadii.append(bottomRightRadiusWidth);
+        if (showHorizontalBottomLeft)
+            horizontalRadii.append(bottomLeftRadiusWidth);
 
-        result.appendLiteral(separator);
-        result.appendLiteral("/");
-        result.appendLiteral(separator);
+        bool showVerticalBottomLeft = topRightRadiusHeight != bottomLeftRadiusHeight;
+        bool showVerticalBottomRight = showVerticalBottomLeft || (bottomRightRadiusHeight != topLeftRadiusHeight);
+        bool showVerticalTopRight = showVerticalBottomRight || (topRightRadiusHeight != topLeftRadiusHeight);
 
-        result.append(topLeftRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(topRightRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(bottomRightRadiusHeight);
-        result.appendLiteral(separator);
-        result.append(bottomLeftRadiusHeight);
+        Vector<String> verticalRadii;
+        verticalRadii.append(topLeftRadiusHeight);
+        if (showVerticalTopRight)
+            verticalRadii.append(topRightRadiusHeight);
+        if (showVerticalBottomRight)
+            verticalRadii.append(bottomRightRadiusHeight);
+        if (showVerticalBottomLeft)
+            verticalRadii.append(bottomLeftRadiusHeight);
+
+        if (!(horizontalRadii.size() == 1 && horizontalRadii[0] == "0px" && verticalRadii[0] == "0px")) {

[Bear Travis, 2014/04/08 19:08:35]

I think this also needs to check for verticalRadii.size being 1, otherwise
you'll miss the case of inset(10px round 0px / 0px 10px). Might be worth
factoring this into a method so you can specify what you're testing, eg
'areDefaultCornerRadii' or some such.

+            result.appendLiteral(separator);
+            result.appendLiteral(cornersSeparator);
+
+            for (size_t i = 0; i < horizontalRadii.size(); ++i) {
+                result.appendLiteral(separator);
+                result.append(horizontalRadii[i]);
+            }
+            if (horizontalRadii != verticalRadii) {
+                result.appendLiteral(separator);
+                result.appendLiteral("/");
+
+                for (size_t i = 0; i < verticalRadii.size(); ++i) {
+                    result.appendLiteral(separator);
+                    result.append(verticalRadii[i]);
+                }
+            }
+        }
     }
     result.append(')');
 
     return result.toString();
 }
 
 static inline void updateCornerRadiusWidthAndHeight(CSSPrimitiveValue* corner, String& width, String& height)
 {
     if (!corner)
         return;
@@ skipping 58 matching lines @@
     visitor->trace(m_left);
     visitor->trace(m_topLeftRadius);
     visitor->trace(m_topRightRadius);
     visitor->trace(m_bottomRightRadius);
     visitor->trace(m_bottomLeftRadius);
     CSSBasicShape::trace(visitor);
 }
 
 } // namespace WebCore