Factor VarPrefix and ArgumentPrefix helpers into base marshaler.

src/Generator/Generators/C/CppMarshal.cs

@@ -333,15 +333,9 @@ namespace CppSharp.Generators.Cpp
 
     public class CppMarshalManagedToNativePrinter : MarshalPrinter<MarshalContext>
     {
-        public readonly TextGenerator VarPrefix;
-        public readonly TextGenerator ArgumentPrefix;
-
         public CppMarshalManagedToNativePrinter(MarshalContext ctx) 
             : base(ctx)
         {
-            VarPrefix = new TextGenerator();
-            ArgumentPrefix = new TextGenerator();
-
             Context.MarshalToNative = this;
         }
 
@@ -414,7 +408,7 @@ namespace CppSharp.Generators.Cpp
                 var isRef = Context.Parameter.Usage == ParameterUsage.Out ||
                     Context.Parameter.Usage == ParameterUsage.InOut;
 
-                ArgumentPrefix.Write("&");
+                Context.ArgumentPrefix.Write("&");
                 Context.Return.Write($"(::{@enum.QualifiedOriginalName}){0}{Context.Parameter.Name}",
                     isRef ? string.Empty : "*");
                 return true;
@@ -586,7 +580,7 @@ namespace CppSharp.Generators.Cpp
                 Context.Return.Write("*");
 
                 if (Context.Parameter.Type.IsReference())
-                    VarPrefix.Write("&");
+                    Context.VarPrefix.Write("&");
             }
 
             var method = Context.Function as Method;

src/Generator/Generators/C/CppSources.cs

@@ -658,8 +658,8 @@ namespace CppSharp.Generators.Cpp
                 if (!string.IsNullOrWhiteSpace(marshal.Context.Before))
                     Write(marshal.Context.Before);
 
-                WriteLine($"auto {marshal.VarPrefix}{argName} = {marshal.Context.Return};");
-                paramMarshal.Prefix = marshal.ArgumentPrefix;
+                WriteLine($"auto {marshal.Context.VarPrefix}{argName} = {marshal.Context.Return};");
+                paramMarshal.Prefix = marshal.Context.ArgumentPrefix;
             }
 
             paramMarshal.Name = argName;

src/Generator/Generators/CLI/CLIMarshal.cs

@@ -738,7 +738,7 @@ namespace CppSharp.Generators.CLI
 
         public void MarshalValueClass(Class @class)
         {
-            var marshalVar = Context.MarshalVarPrefix + "_marshal" +
+            var marshalVar = Context.VarPrefix + "_marshal" +
                 Context.ParameterIndex++;
 
             Context.Before.WriteLine("auto {0} = ::{1}();", marshalVar,
@@ -774,14 +774,12 @@ namespace CppSharp.Generators.CLI
 
         private void MarshalValueClassProperty(Property property, string marshalVar)
         {
-            var fieldRef = string.Format("{0}.{1}", Context.Parameter.Name,
-                                         property.Name);
+            var fieldRef = $"{Context.Parameter.Name}.{property.Name}";
 
             var marshalCtx = new MarshalContext(Context.Context, Context.Indentation)
                                  {
                                      ArgName = fieldRef,
                                      ParameterIndex = Context.ParameterIndex++,
-                                     MarshalVarPrefix = Context.MarshalVarPrefix,
                                      ReturnVarName = $"{marshalVar}.{property.Field.OriginalName}"
                                  };
 

src/Generator/Generators/CLI/CLISources.cs

@@ -968,9 +968,9 @@ namespace CppSharp.Generators.CLI
                 var param = new Parameter { Name = "(*this)" , Namespace = function.Namespace };
                 var ctx = new MarshalContext(Context, CurrentIndentation)
                     {
-                        MarshalVarPrefix = valueMarshalName,
                         Parameter = param
                     };
+                ctx.VarPrefix.Write(valueMarshalName);
 
                 var marshal = new CLIMarshalManagedToNativePrinter(ctx);
                 marshal.MarshalValueClassProperties(@class, valueMarshalName);

src/Generator/Generators/CSharp/CSharpMarshal.cs

@@ -12,12 +12,8 @@ namespace CppSharp.Generators.CSharp
         public CSharpMarshalContext(BindingContext context, uint indentation)
             : base(context, indentation)
         {
-            ArgumentPrefix = new TextGenerator { CurrentIndentation = indentation };
-            Cleanup = new TextGenerator { CurrentIndentation = indentation };
         }
 
-        public TextGenerator ArgumentPrefix { get; }
-        public TextGenerator Cleanup { get; }
         public bool HasCodeBlock { get; set; }
     }
 

src/Generator/Generators/Marshal.cs

@@ -9,7 +9,9 @@ namespace CppSharp.Generators
             Context = context;
             Before = new TextGenerator { CurrentIndentation = indentation };
             Return = new TextGenerator { CurrentIndentation = indentation };
-            MarshalVarPrefix = string.Empty;
+            Cleanup = new TextGenerator { CurrentIndentation = indentation };
+            VarPrefix = new TextGenerator();
+            ArgumentPrefix = new TextGenerator();
             this.Indentation = indentation;
         }
 
@@ -19,6 +21,9 @@ namespace CppSharp.Generators
 
         public TextGenerator Before { get; }
         public TextGenerator Return { get; }
+        public TextGenerator Cleanup { get; }
+        public TextGenerator VarPrefix;
+        public TextGenerator ArgumentPrefix;
 
         public string ReturnVarName { get; set; }
         public QualifiedType ReturnType { get; set; }
@@ -27,7 +32,6 @@ namespace CppSharp.Generators
         public int ParameterIndex { get; set; }
         public Function Function { get; set; }
 
-        public string MarshalVarPrefix { get; set; }
         public uint Indentation { get; }
     }