Dont go down through JNI to figure out that no margin/padding/border/position was set

Summary: Many layout systems query the padding after calculation to as it is needs to be propagated to the underlying view system on the platform. However most nodes have no padding set on them so going 4-6 times through JNI layer to figure this out is a waste of time.

Differential Revision: D4080909

fbshipit-source-id: 7eb1885c615191055aa21e3435c6fbc652b883ae

java/com/facebook/csslayout/CSSNode.java

@@ -40,6 +40,11 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
   private long mNativePointer;
   private Object mData;
 
+  private boolean mHasSetPadding = false;
+  private boolean mHasSetMargin = false;
+  private boolean mHasSetBorder = false;
+  private boolean mHasSetPosition = false;
+
   private native long jni_CSSNodeNew();
   public CSSNode() {
     mNativePointer = jni_CSSNodeNew();
@@ -63,6 +68,10 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
   private native void jni_CSSNodeReset(long nativePointer);
   @Override
   public void reset() {
+    mHasSetPadding = false;
+    mHasSetMargin = false;
+    mHasSetBorder = false;
+    mHasSetPosition = false;
     jni_CSSNodeReset(mNativePointer);
   }
 
@@ -304,48 +313,64 @@ public class CSSNode implements CSSNodeAPI<CSSNode> {
   private native float jni_CSSNodeStyleGetMargin(long nativePointer, int edge);
   @Override
   public float getMargin(int spacingType) {
+    if (!mHasSetMargin) {
+      return spacingType < Spacing.START ? 0 : CSSConstants.UNDEFINED;
+    }
     return jni_CSSNodeStyleGetMargin(mNativePointer, spacingType);
   }
 
   private native void jni_CSSNodeStyleSetMargin(long nativePointer, int edge, float margin);
   @Override
   public void setMargin(int spacingType, float margin) {
+    mHasSetMargin = true;
     jni_CSSNodeStyleSetMargin(mNativePointer, spacingType, margin);
   }
 
   private native float jni_CSSNodeStyleGetPadding(long nativePointer, int edge);
   @Override
   public float getPadding(int spacingType) {
+    if (!mHasSetPadding) {
+      return spacingType < Spacing.START ? 0 : CSSConstants.UNDEFINED;
+    }
     return jni_CSSNodeStyleGetPadding(mNativePointer, spacingType);
   }
 
   private native void jni_CSSNodeStyleSetPadding(long nativePointer, int edge, float padding);
   @Override
   public void setPadding(int spacingType, float padding) {
+    mHasSetPadding = true;
     jni_CSSNodeStyleSetPadding(mNativePointer, spacingType, padding);
   }
 
   private native float jni_CSSNodeStyleGetBorder(long nativePointer, int edge);
   @Override
   public float getBorder(int spacingType) {
+    if (!mHasSetBorder) {
+      return spacingType < Spacing.START ? 0 : CSSConstants.UNDEFINED;
+    }
     return jni_CSSNodeStyleGetBorder(mNativePointer, spacingType);
   }
 
   private native void jni_CSSNodeStyleSetBorder(long nativePointer, int edge, float border);
   @Override
   public void setBorder(int spacingType, float border) {
+    mHasSetBorder = true;
     jni_CSSNodeStyleSetBorder(mNativePointer, spacingType, border);
   }
 
   private native float jni_CSSNodeStyleGetPosition(long nativePointer, int edge);
   @Override
   public float getPosition(int spacingType) {
+    if (!mHasSetPosition) {
+      return CSSConstants.UNDEFINED;
+    }
     return jni_CSSNodeStyleGetPosition(mNativePointer, spacingType);
   }
 
   private native void jni_CSSNodeStyleSetPosition(long nativePointer, int edge, float position);
   @Override
   public void setPosition(int spacingType, float position) {
+    mHasSetPosition = true;
     jni_CSSNodeStyleSetPosition(mNativePointer, spacingType, position);
   }