csharp: Add context information about marshaling direction

This will be used to differentiate annotations between calls from C# to
C functions (DllImport-like) and delegates C# gives to C to be called
back (virtual methods and callbacks).

By default, the root context assumes the managed code calling the native
code.

3 files changed, 37 insertions, 2 deletions

diff --git a/src/bin/eolian_mono/eolian/mono/function_definition.hh b/src/bin/eolian_mono/eolian/mono/function_definition.hh
index cded973d23..5259437e18 100644
--- a/src/bin/eolian_mono/eolian/mono/function_definition.hh
+++ b/src/bin/eolian_mono/eolian/mono/function_definition.hh
@@ -54,6 +54,8 @@ struct native_function_definition_generator
 
     auto const& indent = current_indentation(context);
 
+    auto native_to_managed_context = marshall_direction::from_native_to_managed(context);
+
     // Delegate for the C# method we will export to EO as a method implementation.
     if(!as_generator
        (
@@ -69,7 +71,7 @@ struct native_function_definition_generator
          (marshall_annotation << " " << marshall_parameter)
         ) % ", ")
         << ");\n\n")
-       .generate(sink, std::make_tuple(f.return_type, f.return_type, f.c_name, f.parameters), context))
+       .generate(sink, std::make_tuple(f.return_type, f.return_type, f.c_name, f.parameters), native_to_managed_context))
       return false;
 
     // API delegate is the wrapper for the Eo methods exported from C that we will use from C#.
diff --git a/src/bin/eolian_mono/eolian/mono/generation_contexts.hh b/src/bin/eolian_mono/eolian/mono/generation_contexts.hh
index f7376f056a..a433d942b7 100644
--- a/src/bin/eolian_mono/eolian/mono/generation_contexts.hh
+++ b/src/bin/eolian_mono/eolian/mono/generation_contexts.hh
@@ -50,6 +50,38 @@ struct class_context
     {}
 };
 
+struct marshall_direction
+{
+    enum direction {
+      managed_to_native, // Used for DllImport'd methods
+      native_to_managed, // Used for delegates of functions passed to C to be called back
+    };
+
+    direction current_dir;
+
+    constexpr marshall_direction(direction direction)
+      : current_dir(direction)
+    {}
+
+    template<typename Context>
+    static inline constexpr Context from_native_to_managed(Context const& context)
+    {
+      return efl::eolian::grammar::context_replace_tag(marshall_direction(marshall_direction::native_to_managed), context);
+    }
+
+    template<typename Context>
+    static inline constexpr Context from_managed_to_native(Context const& context)
+    {
+      return efl::eolian::grammar::context_replace_tag(marshall_direction(marshall_direction::managed_to_native), context);
+    }
+
+    template<typename Context>
+    static inline constexpr marshall_direction::direction current_direction(Context const& context)
+    {
+      return efl::eolian::grammar::context_find_tag<marshall_direction>(context).current_dir;
+    }
+};
+
 struct indentation_context
 {
   constexpr indentation_context(indentation_context const& other) = default;
diff --git a/src/bin/eolian_mono/eolian_mono.cc b/src/bin/eolian_mono/eolian_mono.cc
index 62eed11b2a..0d4e58616c 100644
--- a/src/bin/eolian_mono/eolian_mono.cc
+++ b/src/bin/eolian_mono/eolian_mono.cc
@@ -181,6 +181,7 @@ run(options_type const& opts)
    using efl::eolian::grammar::context_add_tag;
 
    auto context = context_add_tag(eolian_mono::indentation_context{0},
+                  context_add_tag(eolian_mono::marshall_direction{eolian_mono::marshall_direction::managed_to_native},
                   context_add_tag(eolian_mono::eolian_state_context{opts.state},
                   context_add_tag(eolian_mono::options_context{opts.want_beta,
                                                                opts.examples_dir},
@@ -188,7 +189,7 @@ run(options_type const& opts)
                                                                opts.v_major,
                                                                opts.v_minor,
                                                                opts.references_map},
-                                  efl::eolian::grammar::context_null()))));
+                                  efl::eolian::grammar::context_null())))));
 
    EINA_ITERATOR_FOREACH(aliases, tp)
      {