Serialize border-image shorthand to shortest form, with the exception that we'll always serialize 'border-image-source'. (Bug 713643, patch 1) r=bzbarsky

layout/style/Declaration.cpp

@@ -264,17 +264,40 @@ Declaration::GetValue(nsCSSProperty aProperty, nsAString& aValue) const
       }
       break;
     }
-    case eCSSProperty_border_image:
+    case eCSSProperty_border_image: {
+      // Even though there are some cases where we could omit
+      // 'border-image-source' (when it's none), it's probably not a
+      // good idea since it's likely to be confusing.  It would also
+      // require adding the extra check that we serialize *something*.
       AppendValueToString(eCSSProperty_border_image_source, aValue);
-      aValue.Append(PRUnichar(' '));
-      AppendValueToString(eCSSProperty_border_image_slice, aValue);
-      aValue.Append(NS_LITERAL_STRING(" / "));
-      AppendValueToString(eCSSProperty_border_image_width, aValue);
-      aValue.Append(NS_LITERAL_STRING(" / "));
-      AppendValueToString(eCSSProperty_border_image_outset, aValue);
-      aValue.Append(PRUnichar(' '));
-      AppendValueToString(eCSSProperty_border_image_repeat, aValue);
+
+      bool sliceDefault = data->HasDefaultBorderImageSlice();
+      bool widthDefault = data->HasDefaultBorderImageWidth();
+      bool outsetDefault = data->HasDefaultBorderImageOutset();
+
+      if (!sliceDefault || !widthDefault || !outsetDefault) {
+        aValue.Append(PRUnichar(' '));
+        AppendValueToString(eCSSProperty_border_image_slice, aValue);
+        if (!widthDefault || !outsetDefault) {
+          aValue.Append(NS_LITERAL_STRING(" /"));
+          if (!widthDefault) {
+            aValue.Append(PRUnichar(' '));
+            AppendValueToString(eCSSProperty_border_image_width, aValue);
+          }
+          if (!outsetDefault) {
+            aValue.Append(NS_LITERAL_STRING(" / "));
+            AppendValueToString(eCSSProperty_border_image_outset, aValue);
+          }
+        }
+      }
+
+      bool repeatDefault = data->HasDefaultBorderImageRepeat();
+      if (!repeatDefault) {
+        aValue.Append(PRUnichar(' '));
+        AppendValueToString(eCSSProperty_border_image_repeat, aValue);
+      }
       break;
+    }
     case eCSSProperty_border: {
       const nsCSSProperty* subproptables[3] = {
         nsCSSProps::SubpropertyEntryFor(eCSSProperty_border_color),

layout/style/nsCSSDataBlock.cpp

@@ -225,6 +225,41 @@ nsCSSCompressedDataBlock::SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf) c
     return n;
 }
 
+bool
+nsCSSCompressedDataBlock::HasDefaultBorderImageSlice() const
+{
+  const nsCSSValueList *slice =
+    ValueFor(eCSSProperty_border_image_slice)->GetListValue();
+  return !slice->mNext &&
+         slice->mValue.GetRectValue().AllSidesEqualTo(
+           nsCSSValue(1.0f, eCSSUnit_Percent));
+}
+
+bool
+nsCSSCompressedDataBlock::HasDefaultBorderImageWidth() const
+{
+  const nsCSSRect &width =
+    ValueFor(eCSSProperty_border_image_width)->GetRectValue();
+  return width.AllSidesEqualTo(nsCSSValue(1.0f, eCSSUnit_Number));
+}
+
+bool
+nsCSSCompressedDataBlock::HasDefaultBorderImageOutset() const
+{
+  const nsCSSRect &outset =
+    ValueFor(eCSSProperty_border_image_outset)->GetRectValue();
+  return outset.AllSidesEqualTo(nsCSSValue(0.0f, eCSSUnit_Number));
+}
+
+bool
+nsCSSCompressedDataBlock::HasDefaultBorderImageRepeat() const
+{
+  const nsCSSValuePair &repeat =
+    ValueFor(eCSSProperty_border_image_repeat)->GetPairValue();
+  return repeat.BothValuesEqualTo(
+    nsCSSValue(NS_STYLE_BORDER_IMAGE_REPEAT_STRETCH, eCSSUnit_Enumerated));
+}
+
 /*****************************************************************************/
 
 nsCSSExpandedDataBlock::nsCSSExpandedDataBlock()

layout/style/nsCSSDataBlock.h

@@ -83,6 +83,11 @@ public:
 
     size_t SizeOfIncludingThis(nsMallocSizeOfFun aMallocSizeOf) const;
 
+    bool HasDefaultBorderImageSlice() const;
+    bool HasDefaultBorderImageWidth() const;
+    bool HasDefaultBorderImageOutset() const;
+    bool HasDefaultBorderImageRepeat() const;
+
 private:
     void* operator new(size_t aBaseSize, PRUint32 aNumProps) {
         NS_ABORT_IF_FALSE(aBaseSize == sizeof(nsCSSCompressedDataBlock),

layout/style/nsCSSValue.h

@@ -706,6 +706,13 @@ struct nsCSSRect {
 
   void SetAllSidesTo(const nsCSSValue& aValue);
 
+  bool AllSidesEqualTo(const nsCSSValue& aValue) const {
+    return mTop == aValue &&
+           mRight == aValue &&
+           mBottom == aValue &&
+           mLeft == aValue;
+  }
+
   void Reset() {
     mTop.Reset();
     mRight.Reset();
@@ -790,6 +797,11 @@ struct nsCSSValuePair {
            mYValue != aOther.mYValue;
   }
 
+  bool BothValuesEqualTo(const nsCSSValue& aValue) const {
+    return mXValue == aValue &&
+           mYValue == aValue;
+  }
+
   void SetBothValuesTo(const nsCSSValue& aValue) {
     mXValue = aValue;
     mYValue = aValue;
@@ -866,6 +878,12 @@ struct nsCSSValueTriplet {
                mZValue != aOther.mZValue;
     }
 
+    bool AllValuesEqualTo(const nsCSSValue& aValue) const {
+        return mXValue == aValue &&
+               mYValue == aValue &&
+               mZValue == aValue;
+    }
+
     void SetAllValuesTo(const nsCSSValue& aValue) {
         mXValue = aValue;
         mYValue = aValue;