Made the checking if a type is const char* universally accessible.

Signed-off-by: Dimitar Dobrev <dpldobrev@protonmail.com>

src/AST/TypeExtensions.cs

@@ -346,6 +346,36 @@
             return left.Equals(right);
         }
 
+        public static bool IsConst(this QualifiedType type)
+        {
+            return type.Type != null && (type.Qualifiers.IsConst ||
+                type.Type.GetQualifiedPointee().IsConst());
+        }
+
+        public static bool IsConstCharString(this Type type)
+        {
+            var desugared = type.Desugar();
+
+            if (!(desugared is PointerType))
+                return false;
+
+            var pointer = desugared as PointerType;
+            return IsConstCharString(pointer);
+        }
+
+        public static bool IsConstCharString(this PointerType pointer)
+        {
+            if (pointer.IsReference)
+                return false;
+
+            var pointee = pointer.Pointee.Desugar();
+
+            return (pointee.IsPrimitiveType(PrimitiveType.Char) ||
+                    pointee.IsPrimitiveType(PrimitiveType.Char16) ||
+                    pointee.IsPrimitiveType(PrimitiveType.WideChar)) &&
+                    pointer.QualifiedPointee.Qualifiers.IsConst;
+        }
+
         public static bool IsDependentPointer(this Type type)
         {
             var desugared = type.Desugar();

src/Generator/Generators/CLI/CLIMarshal.cs

@@ -102,7 +102,7 @@ namespace CppSharp.Generators.CLI
                 return true;
             }
 
-            if (CSharpTypePrinter.IsConstCharString(pointer))
+            if (pointer.IsConstCharString())
             {
                 Context.Return.Write(MarshalStringToManaged(Context.ReturnVarName,
                     pointer.Pointee.Desugar() as BuiltinType));

src/Generator/Generators/CLI/CLITypePrinter.cs

@@ -116,7 +116,7 @@ namespace CppSharp.Generators.CLI
                 return string.Format("{0}^", function.Visit(this, quals));
             }
 
-            if (CSharpTypePrinter.IsConstCharString(pointer))
+            if (pointer.IsConstCharString())
                 return "System::String^";
 
             // From http://msdn.microsoft.com/en-us/library/y31yhkeb.aspx

src/Generator/Generators/CSharp/CSharpMarshal.cs

@@ -157,9 +157,9 @@ namespace CppSharp.Generators.CSharp
             var isRefParam = param != null && (param.IsInOut || param.IsOut);
 
             var pointee = pointer.Pointee.Desugar();
-            bool marshalPointeeAsString = CSharpTypePrinter.IsConstCharString(pointee) && isRefParam;
+            bool marshalPointeeAsString = pointee.IsConstCharString() && isRefParam;
 
-            if ((CSharpTypePrinter.IsConstCharString(pointer) && !MarshalsParameter) ||
+            if ((pointer.IsConstCharString() && !MarshalsParameter) ||
                 marshalPointeeAsString)
             {
                 Context.Return.Write(MarshalStringToManaged(Context.ReturnVarName,
@@ -604,7 +604,7 @@ namespace CppSharp.Generators.CSharp
             var param = Context.Parameter;
             var isRefParam = param != null && (param.IsInOut || param.IsOut);
 
-            if (CSharpTypePrinter.IsConstCharString(pointee) && isRefParam)
+            if (pointee.IsConstCharString() && isRefParam)
             {
                 if (param.IsOut)
                 {
@@ -650,7 +650,7 @@ namespace CppSharp.Generators.CSharp
                 return true;
             }
 
-            var marshalAsString = CSharpTypePrinter.IsConstCharString(pointer);
+            var marshalAsString = pointer.IsConstCharString();
             var finalPointee = pointer.GetFinalPointee();
             PrimitiveType primitive;
             if (finalPointee.IsPrimitiveType(out primitive) || finalPointee.IsEnumType() ||

src/Generator/Generators/CSharp/CSharpSources.cs

@@ -926,8 +926,7 @@ namespace CppSharp.Generators.CSharp
                 if (type.IsPointer())
                 {
                     Type pointee = type.GetFinalPointee();
-                    if (pointee.IsPrimitiveType() &&
+                    if (pointee.IsPrimitiveType() && !type.IsConstCharString())
-                        !CSharpTypePrinter.IsConstCharString(type))
                     {
                         Write($"({CSharpTypePrinter.IntPtrType}) ");
                         var templateSubstitution = pointee.Desugar(false) as TemplateParameterSubstitutionType;

src/Generator/Generators/CSharp/CSharpTypePrinter.cs

@@ -177,35 +177,6 @@ namespace CppSharp.Generators.CSharp
             return string.Format("Func<{0}{1}>", returnTypePrinterResult, args);
         }
 
-        public static bool IsConstCharString(PointerType pointer)
-        {
-            if (pointer.IsReference)
-                return false;
-
-            var pointee = pointer.Pointee.Desugar();
-
-            return (pointee.IsPrimitiveType(PrimitiveType.Char) ||
-                    pointee.IsPrimitiveType(PrimitiveType.Char16) ||
-                    pointee.IsPrimitiveType(PrimitiveType.WideChar)) &&
-                    pointer.QualifiedPointee.Qualifiers.IsConst;
-        }
-
-        public static bool IsConstCharString(Type type)
-        {
-            var desugared = type.Desugar();
-
-            if (!(desugared is PointerType))
-                return false;
-
-            var pointer = desugared as PointerType;
-            return IsConstCharString(pointer);
-        }
-
-        public static bool IsConstCharString(QualifiedType qualType)
-        {
-            return IsConstCharString(qualType.Type);
-        }
-
         private bool allowStrings = true;
 
         public override TypePrinterResult VisitPointerType(PointerType pointer,
@@ -224,7 +195,7 @@ namespace CppSharp.Generators.CSharp
 
             var isManagedContext = ContextKind == TypePrinterContextKind.Managed;
 
-            if (allowStrings && IsConstCharString(pointer))
+            if (allowStrings && pointer.IsConstCharString())
             {
                 if (isManagedContext)
                     return "string";
@@ -259,7 +230,7 @@ namespace CppSharp.Generators.CSharp
                 if (pointee.IsPrimitiveType(PrimitiveType.Void))
                     return IntPtrType;
 
-                if (IsConstCharString(pointee) && isRefParam)
+                if (pointee.IsConstCharString() && isRefParam)
                     return IntPtrType + "*";
 
                 // Do not allow strings inside primitive arrays case, else we'll get invalid types

src/Generator/Types/Std/Stdlib.cs

@@ -93,7 +93,7 @@ namespace CppSharp.Types.Std
 
         public override void CSharpMarshalToManaged(CSharpMarshalContext ctx)
         {
-            var type = ctx.ReturnType.Type.Desugar();
+            var type = Type.Desugar(resolveTemplateSubstitution: false);
             ClassTemplateSpecialization basicString = GetBasicString(type);
             var c_str = basicString.Methods.First(m => m.OriginalName == "c_str");
             var typePrinter = new CSharpTypePrinter(ctx.Context);