From 279c9c83cf316e90f04a0d6c59472a61581bf092 Mon Sep 17 00:00:00 2001
From: triton <ripzonetriton@gmail.com>
Date: Mon, 2 Sep 2013 21:14:35 +0100
Subject: [PATCH] Fixed wrapping of null pointers to actually return null CLR
 references.

---
 src/Generator/Generators/CLI/CLISourcesTemplate.cs   | 10 ++++++++++
 .../Generators/CSharp/CSharpTextTemplate.cs          | 12 ++++++++++++
 tests/Basic/Basic.cpp                                |  5 +++++
 tests/Basic/Basic.h                                  |  1 +
 4 files changed, 28 insertions(+)

diff --git a/src/Generator/Generators/CLI/CLISourcesTemplate.cs b/src/Generator/Generators/CLI/CLISourcesTemplate.cs
index 6625d2a6..13ddc025 100644
--- a/src/Generator/Generators/CLI/CLISourcesTemplate.cs
+++ b/src/Generator/Generators/CLI/CLISourcesTemplate.cs
@@ -809,6 +809,16 @@ namespace CppSharp.Generators.CLI
 
             if (needsReturn)
             {
+                var retTypeName = retType.Visit(TypePrinter);
+                var isIntPtr = retTypeName.Contains("IntPtr");
+
+                if (retType.Type.IsPointer() && (isIntPtr || retTypeName.EndsWith("^")))
+                {
+                    WriteLine("if ({0} == nullptr) return {1};",
+                        Generator.GeneratedIdentifier("ret"),
+                        isIntPtr ? "System::IntPtr()" : "nullptr");
+                }
+
                 var ctx = new MarshalContext(Driver)
                     {
                         ArgName = Generator.GeneratedIdentifier("ret"),
diff --git a/src/Generator/Generators/CSharp/CSharpTextTemplate.cs b/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
index 9b0e70ff..d4eb1dbd 100644
--- a/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
+++ b/src/Generator/Generators/CSharp/CSharpTextTemplate.cs
@@ -1672,6 +1672,18 @@ namespace CppSharp.Generators.CSharp
 
             if (needsReturn)
             {
+                TypePrinter.PushContext(CSharpTypePrinterContextKind.Native);
+                var retTypeName = retType.CSharpType(TypePrinter).Type;
+                TypePrinter.PopContext();
+
+                var isIntPtr = retTypeName.Contains("IntPtr");
+
+                if (retType.Type.IsPointer() && isIntPtr)
+                {
+                    WriteLine("if ({0} == global::System.IntPtr.Zero) return null;",
+                        Generator.GeneratedIdentifier("ret"));
+                }
+
                 var ctx = new CSharpMarshalContext(Driver)
                 {
                     ArgName = GeneratedIdentifier("ret"),
diff --git a/tests/Basic/Basic.cpp b/tests/Basic/Basic.cpp
index 74fcfd40..c40f65b5 100644
--- a/tests/Basic/Basic.cpp
+++ b/tests/Basic/Basic.cpp
@@ -85,6 +85,11 @@ int Hello::RetEnum(Enum e)
     return (int)e;
 }
 
+Hello* Hello::RetNull()
+{
+    return 0;
+}
+
 int unsafeFunction(const Bar& ret, char* testForString, void (*foo)(int))
 {
     return ret.A;
diff --git a/tests/Basic/Basic.h b/tests/Basic/Basic.h
index bf48e043..4228e2fd 100644
--- a/tests/Basic/Basic.h
+++ b/tests/Basic/Basic.h
@@ -77,6 +77,7 @@ public:
     int AddBar2(Bar2);
 
     int RetEnum(Enum);
+    Hello* RetNull();
 };
 
 DLL_API Bar operator-(const Bar &);