Adds a setting to force some types to always be included in the emitted types

csbindgen/src/builder.rs

@@ -32,6 +32,7 @@ pub struct BindgenOptions {
     pub csharp_use_nint_types: bool,
     pub csharp_imported_namespaces: Vec<String>,
     pub csharp_generate_const_filter: fn(const_name: &str) -> bool,
+    pub always_included_types: Vec<String>,
 }
 
 impl Default for Builder {
@@ -57,6 +58,7 @@ impl Default for Builder {
                 csharp_use_nint_types: true,
                 csharp_imported_namespaces: vec![],
                 csharp_generate_const_filter: |_| false,
+                always_included_types: vec![],
             },
         }
     }
@@ -87,7 +89,14 @@ impl Builder {
         self
     }
 
-
+    /// Adds a list of types that will always be considered to be included in the
+    /// generated bindings, even if not part of any function signature
+    pub fn always_included_types<I, S>(mut self, always_included_types: I) -> Builder
+    where I: IntoIterator<Item = S>, S: ToString
+    {
+        self.options.always_included_types.extend(always_included_types.into_iter().map(|v| v.to_string()));
+        self
+    }
 
     /// add original extern call type prefix to rust wrapper,
     /// `return {rust_method_type_path}::foo()`

csbindgen/src/lib.rs

@@ -78,6 +78,8 @@ pub(crate) fn generate(
         }
     }
 
+    using_types.extend(options.always_included_types.iter().cloned());
+
     let structs = reduce_struct(&structs, &field_map, &using_types);
     let enums = reduce_enum(&enums, &field_map, &using_types);