feat: support null when serializing classes (#2290)

MirageNet · Sep 29, 2020 · 513a0f9 · 513a0f9
1 parent fe641ad
commit 513a0f9
Show file tree

Hide file tree

Showing 3 changed files with 75 additions and 0 deletions.
diff --git a/Assets/Mirror/Editor/Weaver/Readers.cs b/Assets/Mirror/Editor/Weaver/Readers.cs
@@ -397,6 +397,9 @@ static MethodDefinition GenerateClassOrStructReadFunction(TypeReference variable
 
             TypeDefinition td = variable.Resolve();
 
+            if (!td.IsValueType)
+                GenerateNullCheck(worker);
+
             CreateNew(variable, worker, td);
             ReadAllFields(variable, recursionCount, worker);
 
@@ -405,6 +408,23 @@ static MethodDefinition GenerateClassOrStructReadFunction(TypeReference variable
             return readerFunc;
         }
 
+        private static void GenerateNullCheck(ILProcessor worker)
+        {
+            // if (!reader.ReadBoolean()) {
+            //   return null;
+            // }
+
+            worker.Append(worker.Create(OpCodes.Ldarg_0));
+            worker.Append(worker.Create(OpCodes.Call, GetReadFunc(WeaverTypes.Import<bool>())));
+
+            Instruction labelEmptyArray = worker.Create(OpCodes.Nop);
+            worker.Append(worker.Create(OpCodes.Brtrue, labelEmptyArray));
+            // return null
+            worker.Append(worker.Create(OpCodes.Ldnull));
+            worker.Append(worker.Create(OpCodes.Ret));
+            worker.Append(labelEmptyArray);
+        }
+
         // Initialize the local variable with a new instance
         static void CreateNew(TypeReference variable, ILProcessor worker, TypeDefinition td)
         {

diff --git a/Assets/Mirror/Editor/Weaver/Writers.cs b/Assets/Mirror/Editor/Weaver/Writers.cs
@@ -178,13 +178,40 @@ static MethodDefinition GenerateClassOrStructWriterFunction(TypeReference variab
 
             ILProcessor worker = writerFunc.Body.GetILProcessor();
 
+            if (!variable.Resolve().IsValueType)
+                WriteNullCheck(worker);
+
             if (!WriteAllFields(variable, recursionCount, worker))
                 return null;
 
             worker.Append(worker.Create(OpCodes.Ret));
             return writerFunc;
         }
 
+        private static void WriteNullCheck(ILProcessor worker)
+        {
+            // if (value == null)
+            // {
+            //  writer.WriteBoolean(false);
+            //  return;
+            // }
+            //
+
+            Instruction labelNotNull = worker.Create(OpCodes.Nop);
+            worker.Append(worker.Create(OpCodes.Ldarg_1));
+            worker.Append(worker.Create(OpCodes.Brtrue, labelNotNull));
+            worker.Append(worker.Create(OpCodes.Ldarg_0));
+            worker.Append(worker.Create(OpCodes.Ldc_I4_0));
+            worker.Append(worker.Create(OpCodes.Call,  GetWriteFunc(WeaverTypes.Import<bool>())));
+            worker.Append(worker.Create(OpCodes.Ret));
+            worker.Append(labelNotNull);
+
+            // write.WriteBoolean(true);
+            worker.Append(worker.Create(OpCodes.Ldarg_0));
+            worker.Append(worker.Create(OpCodes.Ldc_I4_1));
+            worker.Append(worker.Create(OpCodes.Call, GetWriteFunc(WeaverTypes.Import<bool>())));
+        }
+
         /// <summary>
         /// Find all fields in type and write them
         /// </summary>

diff --git a/Assets/Mirror/Tests/Editor/MessageBaseTests.cs b/Assets/Mirror/Tests/Editor/MessageBaseTests.cs
@@ -83,6 +83,17 @@ class Layer3Message : Layer2Message
         public int value3;
     }
 
+    class NullableObject
+    {
+        public int id = 3;
+    }
+
+    class NullableObjectMessage : MessageBase
+    {
+        public string name;
+        public NullableObject nullObj;
+    }
+
     [TestFixture]
     public class MessageBaseTests
     {
@@ -158,5 +169,22 @@ public void MessageInheirtanceWorksWithMultipleLayers()
             Assert.That(unpacked.value2, Is.EqualTo(value2));
             Assert.That(unpacked.value3, Is.EqualTo(value3));
         }
+
+        [Test]
+        public void NullObjectMessageTest()
+        {
+            NullableObjectMessage nullableObjectMessage = new NullableObjectMessage
+            {
+                name = "pepe",
+                nullObj = null
+            };
+
+            byte[] data = MessagePacker.Pack(nullableObjectMessage);
+
+            NullableObjectMessage unpacked = MessagePacker.Unpack<NullableObjectMessage>(data);
+
+            Assert.That(unpacked.name, Is.EqualTo("pepe"));
+            Assert.That(unpacked.nullObj, Is.Null);
+        }
     }
 }