Bug 613659 - Implement box-decoration-break in the style system. r=cam

layout/style/nsCSSKeywordList.h

@@ -208,6 +208,7 @@ CSS_KEY(circle, circle)
 CSS_KEY(cjk-decimal, cjk_decimal)
 CSS_KEY(cjk-ideographic, cjk_ideographic)
 CSS_KEY(clip, clip)
+CSS_KEY(clone, clone)
 CSS_KEY(close-quote, close_quote)
 CSS_KEY(closest-corner, closest_corner)
 CSS_KEY(closest-side, closest_side)
@@ -497,6 +498,7 @@ CSS_KEY(skew, skew)
 CSS_KEY(skewx, skewx)
 CSS_KEY(skewy, skewy)
 CSS_KEY(slashed-zero, slashed_zero)
+CSS_KEY(slice, slice)
 CSS_KEY(small, small)
 CSS_KEY(small-caps, small_caps)
 CSS_KEY(small-caption, small_caption)

layout/style/nsCSSPropList.h

@@ -1365,6 +1365,16 @@ CSS_PROP_POSITION(
     nullptr,
     offsetof(nsStylePosition, mOffset),
     eStyleAnimType_Sides_Bottom)
+CSS_PROP_BORDER(
+    box-decoration-break,
+    box_decoration_break,
+    BoxDecorationBreak,
+    CSS_PROPERTY_PARSE_VALUE,
+    "layout.css.box-decoration-break.enabled",
+    VARIANT_HK,
+    kBoxDecorationBreakKTable,
+    CSS_PROP_NO_OFFSET,
+    eStyleAnimType_None)
 CSS_PROP_BORDER(
     box-shadow,
     box_shadow,

layout/style/nsCSSProps.cpp

@@ -796,6 +796,12 @@ const KTableValue nsCSSProps::kBoxPropSourceKTable[] = {
   eCSSKeyword_UNKNOWN,-1
 };
 
+const KTableValue nsCSSProps::kBoxDecorationBreakKTable[] = {
+  eCSSKeyword_slice, NS_STYLE_BOX_DECORATION_BREAK_SLICE,
+  eCSSKeyword_clone, NS_STYLE_BOX_DECORATION_BREAK_CLONE,
+  eCSSKeyword_UNKNOWN,-1
+};
+
 const KTableValue nsCSSProps::kBoxShadowTypeKTable[] = {
   eCSSKeyword_inset, NS_STYLE_BOX_SHADOW_INSET,
   eCSSKeyword_UNKNOWN,-1

layout/style/nsCSSProps.h

@@ -520,6 +520,7 @@ public:
   static const KTableValue kBorderStyleKTable[];
   static const KTableValue kBorderWidthKTable[];
   static const KTableValue kBoxAlignKTable[];
+  static const KTableValue kBoxDecorationBreakKTable[];
   static const KTableValue kBoxDirectionKTable[];
   static const KTableValue kBoxOrientKTable[];
   static const KTableValue kBoxPackKTable[];

layout/style/nsComputedDOMStyle.cpp

@@ -2980,6 +2980,16 @@ nsComputedDOMStyle::GetCSSShadowArray(nsCSSShadowArray* aArray,
   return valueList;
 }
 
+CSSValue*
+nsComputedDOMStyle::DoGetBoxDecorationBreak()
+{
+  nsROCSSPrimitiveValue* val = new nsROCSSPrimitiveValue;
+  val->SetIdent(
+    nsCSSProps::ValueToKeywordEnum(StyleBorder()->mBoxDecorationBreak,
+                                   nsCSSProps::kBoxDecorationBreakKTable));
+  return val;
+}
+
 CSSValue*
 nsComputedDOMStyle::DoGetBoxShadow()
 {

layout/style/nsComputedDOMStyle.h

@@ -222,6 +222,7 @@ private:
 
   /* Box properties */
   mozilla::dom::CSSValue* DoGetBoxAlign();
+  mozilla::dom::CSSValue* DoGetBoxDecorationBreak();
   mozilla::dom::CSSValue* DoGetBoxDirection();
   mozilla::dom::CSSValue* DoGetBoxFlex();
   mozilla::dom::CSSValue* DoGetBoxOrdinalGroup();

layout/style/nsRuleNode.cpp

@@ -6445,6 +6445,13 @@ nsRuleNode::ComputeBorderData(void* aStartStruct,
 {
   COMPUTE_START_RESET(Border, (mPresContext), border, parentBorder)
 
+  // box-decoration-break: enum, inherit, initial
+  SetDiscrete(*aRuleData->ValueForBoxDecorationBreak(),
+              border->mBoxDecorationBreak, canStoreInRuleTree,
+              SETDSC_ENUMERATED | SETDSC_UNSET_INITIAL,
+              parentBorder->mBoxDecorationBreak,
+              NS_STYLE_BOX_DECORATION_BREAK_SLICE, 0, 0, 0, 0);
+
   // box-shadow: none, list, inherit, initial
   const nsCSSValue* boxShadowValue = aRuleData->ValueForBoxShadow();
   switch (boxShadowValue->GetUnit()) {

layout/style/nsStyleConsts.h

@@ -117,6 +117,10 @@ static inline mozilla::css::Side operator++(mozilla::css::Side& side, int) {
 #define NS_STYLE_BOX_PACK_END          2
 #define NS_STYLE_BOX_PACK_JUSTIFY      3
 
+// box-decoration-break
+#define NS_STYLE_BOX_DECORATION_BREAK_SLICE  0
+#define NS_STYLE_BOX_DECORATION_BREAK_CLONE  1
+
 // box-direction
 #define NS_STYLE_BOX_DIRECTION_NORMAL    0
 #define NS_STYLE_BOX_DIRECTION_REVERSE   1

layout/style/nsStyleStruct.cpp

@@ -388,6 +388,7 @@ nsStyleBorder::nsStyleBorder(nsPresContext* aPresContext)
     mBorderImageRepeatH(NS_STYLE_BORDER_IMAGE_REPEAT_STRETCH),
     mBorderImageRepeatV(NS_STYLE_BORDER_IMAGE_REPEAT_STRETCH),
     mFloatEdge(NS_STYLE_FLOAT_EDGE_CONTENT),
+    mBoxDecorationBreak(NS_STYLE_BOX_DECORATION_BREAK_SLICE),
     mComputedBorder(0, 0, 0, 0)
 {
   MOZ_COUNT_CTOR(nsStyleBorder);
@@ -439,6 +440,7 @@ nsStyleBorder::nsStyleBorder(const nsStyleBorder& aSrc)
     mBorderImageRepeatH(aSrc.mBorderImageRepeatH),
     mBorderImageRepeatV(aSrc.mBorderImageRepeatV),
     mFloatEdge(aSrc.mFloatEdge),
+    mBoxDecorationBreak(aSrc.mBoxDecorationBreak),
     mComputedBorder(aSrc.mComputedBorder),
     mBorder(aSrc.mBorder),
     mTwipsPerPixel(aSrc.mTwipsPerPixel)
@@ -528,7 +530,8 @@ nsChangeHint nsStyleBorder::CalcDifference(const nsStyleBorder& aOther) const
       GetComputedBorder() != aOther.GetComputedBorder() ||
       mFloatEdge != aOther.mFloatEdge ||
       mBorderImageOutset != aOther.mBorderImageOutset ||
-      (shadowDifference & nsChangeHint_NeedReflow))
+      (shadowDifference & nsChangeHint_NeedReflow) ||
+      mBoxDecorationBreak != aOther.mBoxDecorationBreak)
     return NS_STYLE_HINT_REFLOW;
 
   NS_FOR_CSS_SIDES(ix) {

layout/style/nsStyleStruct.h

@@ -986,6 +986,7 @@ public:
   uint8_t        mBorderImageRepeatH; // [reset] see nsStyleConsts.h
   uint8_t        mBorderImageRepeatV; // [reset]
   uint8_t        mFloatEdge;          // [reset]
+  uint8_t        mBoxDecorationBreak; // [reset] see nsStyleConsts.h
 
 protected:
   // mComputedBorder holds the CSS2.1 computed border-width values.

layout/style/test/property_database.js

@@ -5394,6 +5394,17 @@ if (SpecialPowers.getBoolPref("layout.css.overflow-clip-box.enabled")) {
 	};
 }
 
+if (SpecialPowers.getBoolPref("layout.css.box-decoration-break.enabled")) {
+	gCSSProperties["box-decoration-break"] = {
+		domProp: "boxDecorationBreak",
+		inherited: false,
+		type: CSS_TYPE_LONGHAND,
+		initial_values: [ "slice" ],
+		other_values: [ "clone" ],
+		invalid_values: [ "auto",  "none",  "1px" ]
+	};
+}
+
 if (SpecialPowers.getBoolPref("layout.css.unset-value.enabled")) {
   gCSSProperties["animation-direction"].invalid_values.push("normal, unset");
   gCSSProperties["animation-name"].invalid_values.push("bounce, unset", "unset, bounce");

modules/libpref/src/init/all.js

@@ -1901,6 +1901,9 @@ pref("layout.css.overflow-clip-box.enabled", false);
 // Is support for CSS grid enabled?
 pref("layout.css.grid.enabled", false);
 
+// Is support for CSS box-decoration-break enabled?
+pref("layout.css.box-decoration-break.enabled", false);
+
 // pref for which side vertical scrollbars should be on
 // 0 = end-side in UI direction
 // 1 = end-side in document/content direction