Update CSSNodeFree for C#, Java and Objective-C

Summary:
- Update CSSNodeFree to unlink parent and children for C#, Java and Objective-C bindings finalizer.
- [C#] Fix build (Fix #232)
- [C#] Add Clear API for convenience as CSSNodeFreeRecursive.
- [C#] Revise and add unit tests

Reviewed By: emilsjolander

Differential Revision: D4069655

fbshipit-source-id: 1fd764059784d7968af38b6aaf7fb6f70fdee8ee

CSSLayout/CSSLayout.c

@@ -155,6 +155,17 @@ CSSNodeRef CSSNodeNew(void) {
 }
 
 void CSSNodeFree(const CSSNodeRef node) {
+  if (node->parent) {
+    CSSNodeListDelete(node->parent->children, node);
+    node->parent = NULL;
+  }
+
+  const uint32_t childCount = CSSNodeChildCount(node);
+  for (uint32_t i = 0; i < childCount; i++) {
+    const CSSNodeRef child = CSSNodeGetChild(node, i);
+    child->parent = NULL;
+  }
+
   CSSNodeListFree(node->children);
   free(node);
   gNodeInstanceCount--;

csharp/Facebook.CSSLayout/CSSNode.cs

@@ -15,7 +15,7 @@ using System.Text;
 
 namespace Facebook.CSSLayout
 {
-    public class CSSNode : IDisposable, IEnumerable<CSSNode>
+    public class CSSNode : IEnumerable<CSSNode>
     {
         private IntPtr _cssNode;
 
@@ -35,7 +35,6 @@ namespace Facebook.CSSLayout
             {
                 throw new InvalidOperationException("Failed to allocate native memory");
             }
-
         }
 
         ~CSSNode()
@@ -483,6 +482,14 @@ namespace Facebook.CSSLayout
             Native.CSSNodeRemoveChild(_cssNode, child._cssNode);
         }
 
+        public void Clear()
+        {
+            while (_children.Count > 0)
+            {
+                RemoveAt(0);
+            }
+        }
+
         public int IndexOf(CSSNode node)
         {
             return _children.IndexOf(node);

csharp/tests/Facebook.CSSLayout/CSSNodeTest.cs

@@ -52,117 +52,50 @@ namespace Facebook.CSSLayout
         }
 
         [Test]
-        [ExpectedException("System.InvalidOperationException")]
+        public void TestReset()
-        public void TestAlreadyInitialize()
         {
-            CSSNode node = new CSSNode();
-            node.Reinitialize();
-        }
-
-        [Test]
-        [ExpectedException("System.InvalidOperationException")]
-        public void TestNullNativePointer()
-        {
-            CSSNode node = new CSSNode();
-            node.Free();
-            node.CalculateLayout();
-        }
-
-        [Test]
-        [ExpectedException("System.InvalidOperationException")]
-        public void TestDoubleFree()
-        {
-            CSSNode node = new CSSNode();
-            node.Free();
-            node.Free();
-        }
-
-        [Test]
-        public void TestReinitialize()
-        {
-            CSSNode node = new CSSNode();
-            node.Free();
-            node.Reinitialize();
-        }
-
-        [Test]
-        [ExpectedException("System.ObjectDisposedException")]
-        public void TestDisposed()
-        {
-            CSSNode node = new CSSNode();
-            node.Dispose();
-            node.CalculateLayout();
-        }
-
-        [Test]
-        public void TestFree()
-        {
-            CSSNode node = new CSSNode();
-            node.Free();
-        }
-
-        [Test]
-        public void TestDispose()
-        {
-            ForceGC();
             int instanceCount = CSSNode.GetInstanceCount();
             CSSNode node = new CSSNode();
             Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-            node.Dispose();
+            node.Reset();
-            Assert.AreEqual(instanceCount, CSSNode.GetInstanceCount());
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-        }
-
-        [Test]
-        public void TestDisposeWithUsing()
-        {
-            ForceGC();
-            int instanceCount = CSSNode.GetInstanceCount();
-            using (CSSNode node = new CSSNode())
-            {
-                Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-            }
-            Assert.AreEqual(instanceCount, CSSNode.GetInstanceCount());
         }
 
         [Test]
         [ExpectedException("System.InvalidOperationException")]
-        public void TestFreeParent()
+        public void TestResetParent()
         {
             CSSNode parent = new CSSNode();
             CSSNode child = new CSSNode();
             parent.Insert(0, child);
-            parent.Free();
+            parent.Reset();
         }
 
         [Test]
         [ExpectedException("System.InvalidOperationException")]
-        public void TestFreeChild()
+        public void TestResetChild()
         {
             CSSNode parent = new CSSNode();
             CSSNode child = new CSSNode();
             parent.Insert(0, child);
-            child.Free();
+            child.Reset();
         }
 
         [Test]
-        public void TestDisposeChild()
+        public void TestClear()
         {
-            ForceGC();
             int instanceCount = CSSNode.GetInstanceCount();
             CSSNode parent = new CSSNode();
-            CSSNode child0 = new CSSNode();
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-            CSSNode child1 = new CSSNode();
+            CSSNode child = new CSSNode();
-            Assert.AreEqual(instanceCount + 3, CSSNode.GetInstanceCount());
-            Assert.AreEqual(0, parent.Count);
-            parent.Insert(0, child1);
-            Assert.AreEqual(0, parent.IndexOf(child1));
-            parent.Insert(0, child0);
-            Assert.AreEqual(0, parent.IndexOf(child0));
-            Assert.AreEqual(1, parent.IndexOf(child1));
-            child0.Dispose();
             Assert.AreEqual(instanceCount + 2, CSSNode.GetInstanceCount());
+            parent.Insert(0, child);
             Assert.AreEqual(1, parent.Count);
-            Assert.AreEqual(0, parent.IndexOf(child1));
+            Assert.AreEqual(parent, child.Parent);
+            parent.Clear();
+            Assert.AreEqual(0, parent.Count);
+            Assert.IsNull(child.Parent);
+            Assert.AreEqual(instanceCount + 2, CSSNode.GetInstanceCount());
         }
 
         [Test]
@@ -257,26 +190,48 @@ namespace Facebook.CSSLayout
         }
 
         [Test]
-        public void TestDisposeParent()
+        public void TestParentDestructor()
         {
             ForceGC();
             int instanceCount = CSSNode.GetInstanceCount();
-            CSSNode parent = new CSSNode();
+            CSSNode child = new CSSNode();
             Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-            TestDisposeParentForGC(parent, instanceCount + 1);
+
+            TestParentDestructorForGC(child, instanceCount + 1);
             ForceGC();
-            Assert.AreEqual(instanceCount + 2, CSSNode.GetInstanceCount());
+
-            parent.Dispose();
+            Assert.IsNull(child.Parent);
-            ForceGC();
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
-            Assert.AreEqual(instanceCount, CSSNode.GetInstanceCount());
         }
 
-        private void TestDisposeParentForGC(CSSNode parent, int instanceCount)
+        private void TestParentDestructorForGC(CSSNode child, int instanceCount)
+        {
+            CSSNode parent = new CSSNode();
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
+            parent.Insert(0, child);
+        }
+
+        [Test]
+        public void TestClearWithChildDestructor()
+        {
+            ForceGC();
+            int instanceCount = CSSNode.GetInstanceCount();
+            CSSNode node = new CSSNode();
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
+            TestClearWithChildDestructorForGC(node, instanceCount + 1);
+            ForceGC();
+            Assert.AreEqual(instanceCount + 2, CSSNode.GetInstanceCount());
+            node.Clear();
+            Assert.AreEqual(0, node.Count);
+            ForceGC();
+            Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
+        }
+
+        private void TestClearWithChildDestructorForGC(CSSNode parent, int instanceCount)
         {
             CSSNode child = new CSSNode();
             Assert.AreEqual(instanceCount + 1, CSSNode.GetInstanceCount());
             parent.Insert(0, child);
-            child = null;
         }
 #endif
     }