Bug 1028460 - part 1, Implement a mozilla::Sides type that represents a set of sides that can be used for the GetSkipSides() result among other things. r=roc

gfx/2d/BaseMargin.h

@@ -9,6 +9,57 @@
 #include "Types.h"
 
 namespace mozilla {
+
+/**
+ * Sides represents a set of physical sides.
+ */
+struct Sides MOZ_FINAL {
+  Sides() : mBits(0) {}
+  explicit Sides(SideBits aSideBits)
+  {
+    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
+    mBits = aSideBits;
+  }
+  bool IsEmpty() const { return mBits == 0; }
+  bool Top()     const { return mBits & eSideBitsTop; }
+  bool Right()   const { return mBits & eSideBitsRight; }
+  bool Bottom()  const { return mBits & eSideBitsBottom; }
+  bool Left()    const { return mBits & eSideBitsLeft; }
+  bool Contains(SideBits aSideBits) const
+  {
+    MOZ_ASSERT((aSideBits & ~eSideBitsAll) == 0, "illegal side bits");
+    return (mBits & aSideBits) == aSideBits;
+  }
+  Sides operator|(Sides aOther) const
+  {
+    return Sides(SideBits(mBits | aOther.mBits));
+  }
+  Sides operator|(SideBits aSideBits) const
+  {
+    return *this | Sides(aSideBits);
+  }
+  Sides& operator|=(Sides aOther)
+  {
+    mBits |= aOther.mBits;
+    return *this;
+  }
+  Sides& operator|=(SideBits aSideBits)
+  {
+    return *this |= Sides(aSideBits);
+  }
+  bool operator==(Sides aOther) const
+  {
+    return mBits == aOther.mBits;
+  }
+  bool operator!=(Sides aOther) const
+  {
+    return !(*this == aOther);
+  }
+
+private:
+  uint8_t mBits;
+};
+
 namespace gfx {
 
 /**
@@ -17,7 +68,7 @@ namespace gfx {
  */
 template <class T, class Sub>
 struct BaseMargin {
-  typedef mozilla::css::Side SideT;
+  typedef mozilla::Side SideT; // because we have a method named Side
 
   // Do not change the layout of these members; the Side() methods below
   // depend on this order.
@@ -45,18 +96,18 @@ struct BaseMargin {
     return *(&top + T(aSide));
   }
 
-  void ApplySkipSides(int aSkipSides)
+  void ApplySkipSides(Sides aSkipSides)
   {
-    if (aSkipSides & (1 << mozilla::css::eSideTop)) {
+    if (aSkipSides.Top()) {
       top = 0;
     }
-    if (aSkipSides & (1 << mozilla::css::eSideRight)) {
+    if (aSkipSides.Right()) {
       right = 0;
     }
-    if (aSkipSides & (1 << mozilla::css::eSideBottom)) {
+    if (aSkipSides.Bottom()) {
       bottom = 0;
     }
-    if (aSkipSides & (1 << mozilla::css::eSideLeft)) {
+    if (aSkipSides.Left()) {
       left = 0;
     }
   }

gfx/2d/Types.h

@@ -264,17 +264,25 @@ struct GradientStop
 #define GFX2D_API
 #endif
 
-// Side constants for use in various places
 namespace mozilla {
-  namespace css {
-    enum Side {eSideTop, eSideRight, eSideBottom, eSideLeft};
-  }
-}
+// Side constants for use in various places.
+enum Side { eSideTop, eSideRight, eSideBottom, eSideLeft };
 
-// XXX - These don't really belong here. But for now this is where they go.
-#define NS_SIDE_TOP     mozilla::css::eSideTop
-#define NS_SIDE_RIGHT   mozilla::css::eSideRight
-#define NS_SIDE_BOTTOM  mozilla::css::eSideBottom
-#define NS_SIDE_LEFT    mozilla::css::eSideLeft
+enum SideBits {
+  eSideBitsNone   = 0,
+  eSideBitsTop    = 1 << eSideTop,
+  eSideBitsRight  = 1 << eSideRight,
+  eSideBitsBottom = 1 << eSideBottom,
+  eSideBitsLeft   = 1 << eSideLeft,
+  eSideBitsTopBottom = eSideBitsTop  | eSideBitsBottom,
+  eSideBitsLeftRight = eSideBitsLeft | eSideBitsRight,
+  eSideBitsAll = eSideBitsTopBottom | eSideBitsLeftRight
+};
+} // namespace mozilla
+
+#define NS_SIDE_TOP    mozilla::eSideTop
+#define NS_SIDE_RIGHT  mozilla::eSideRight
+#define NS_SIDE_BOTTOM mozilla::eSideBottom
+#define NS_SIDE_LEFT   mozilla::eSideLeft
 
 #endif /* MOZILLA_GFX_TYPES_H_ */