Merge pull request #19 from TheBlueMatt/2021-04-invoice-incl
[ldk-c-bindings] / c-bindings-gen / src / main.rs
index 0d002bbbeb40421598b34add308071dc7afe6532..c2ef30fbcf83a9e0c37204e1ee1b0f9466756ba4 100644 (file)
@@ -25,12 +25,16 @@ use std::io::{Read, Write};
 use std::process;
 
 use proc_macro2::Span;
+use quote::format_ident;
+use syn::parse_quote;
 
 mod types;
 mod blocks;
 use types::*;
 use blocks::*;
 
+const DEFAULT_IMPORTS: &'static str = "\nuse std::str::FromStr;\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n";
+
 // *************************************
 // *** Manually-expanded conversions ***
 // *************************************
@@ -63,10 +67,8 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                                writeln!(w, "/// Serialize the {} object into a byte array which can be read by {}_read", for_obj, for_obj).unwrap();
                                writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
 
-                               let ref_type = syn::Type::Reference(syn::TypeReference {
-                                       and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
-                                       elem: Box::new(for_ty.clone()) });
-                               assert!(!types.write_from_c_conversion_new_var(w, &syn::Ident::new("obj", Span::call_site()), &ref_type, Some(generics)));
+                               let ref_type: syn::Type = syn::parse_quote!(&#for_ty);
+                               assert!(!types.write_from_c_conversion_new_var(w, &format_ident!("obj"), &ref_type, Some(generics)));
 
                                write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
                                types.write_from_c_conversion_prefix(w, &ref_type, Some(generics));
@@ -84,26 +86,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                        },
                        "lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs" => {
                                // Create the Result<Object, DecodeError> syn::Type
-                               let mut err_segs = syn::punctuated::Punctuated::new();
-                               err_segs.push(syn::PathSegment { ident: syn::Ident::new("ln", Span::call_site()), arguments: syn::PathArguments::None });
-                               err_segs.push(syn::PathSegment { ident: syn::Ident::new("msgs", Span::call_site()), arguments: syn::PathArguments::None });
-                               err_segs.push(syn::PathSegment { ident: syn::Ident::new("DecodeError", Span::call_site()), arguments: syn::PathArguments::None });
-                               let mut args = syn::punctuated::Punctuated::new();
-                               args.push(syn::GenericArgument::Type(for_ty.clone()));
-                               args.push(syn::GenericArgument::Type(syn::Type::Path(syn::TypePath {
-                                       qself: None, path: syn::Path {
-                                               leading_colon: Some(syn::Token![::](Span::call_site())), segments: err_segs,
-                                       }
-                               })));
-                               let mut res_segs = syn::punctuated::Punctuated::new();
-                               res_segs.push(syn::PathSegment {
-                                       ident: syn::Ident::new("Result", Span::call_site()),
-                                       arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
-                                               colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
-                                       })
-                               });
-                               let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path {
-                                       leading_colon: None, segments: res_segs } });
+                               let res_ty: syn::Type = parse_quote!(Result<#for_ty, ::ln::msgs::DecodeError>);
 
                                writeln!(w, "#[no_mangle]").unwrap();
                                writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
@@ -120,7 +103,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                                                if let syn::GenericArgument::Type(args_ty) = args.args.iter().next().unwrap() {
                                                        types.write_c_type(w, args_ty, Some(generics), false);
 
-                                                       assert!(!types.write_from_c_conversion_new_var(&mut arg_conv, &syn::Ident::new("arg", Span::call_site()), &args_ty, Some(generics)));
+                                                       assert!(!types.write_from_c_conversion_new_var(&mut arg_conv, &format_ident!("arg"), &args_ty, Some(generics)));
 
                                                        write!(&mut arg_conv, "\tlet arg_conv = ").unwrap();
                                                        types.write_from_c_conversion_prefix(&mut arg_conv, &args_ty, Some(generics));
@@ -143,7 +126,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                                        writeln!(w, "\tlet res = crate::c_types::deserialize_obj(ser);").unwrap();
                                }
                                write!(w, "\t").unwrap();
-                               if types.write_to_c_conversion_new_var(w, &syn::Ident::new("res", Span::call_site()), &res_ty, Some(generics), false) {
+                               if types.write_to_c_conversion_new_var(w, &format_ident!("res"), &res_ty, Some(generics), false) {
                                        write!(w, "\n\t").unwrap();
                                }
                                types.write_to_c_conversion_inline_prefix(w, &res_ty, Some(generics), false);
@@ -244,7 +227,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
        }
        writeln_docs(w, &t.attrs, "");
 
-       let mut gen_types = GenericTypes::new();
+       let mut gen_types = GenericTypes::new(None);
        assert!(gen_types.learn_generics(&t.generics, types));
        gen_types.learn_associated_types(&t, types);
 
@@ -405,7 +388,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                                                                                                        ident.mutability.is_some() || ident.subpat.is_some() {
                                                                                                unimplemented!();
                                                                                        }
-                                                                                       write!(w, ", {}{}: ", if $type_resolver.skip_arg(&*arg.ty, Some(&meth_gen_types)) { "_" } else { "" }, ident.ident).unwrap();
+                                                                                       write!(w, ", mut {}{}: ", if $type_resolver.skip_arg(&*arg.ty, Some(&meth_gen_types)) { "_" } else { "" }, ident.ident).unwrap();
                                                                                }
                                                                                _ => unimplemented!(),
                                                                        }
@@ -598,7 +581,10 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
        writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
 
        if let syn::Fields::Named(fields) = &s.fields {
-               let mut gen_types = GenericTypes::new();
+               let mut self_path_segs = syn::punctuated::Punctuated::new();
+               self_path_segs.push(s.ident.clone().into());
+               let self_path = syn::Path { leading_colon: None, segments: self_path_segs};
+               let mut gen_types = GenericTypes::new(Some((types.resolve_path(&self_path, None), &self_path)));
                assert!(gen_types.learn_generics(&s.generics, types));
 
                let mut all_fields_settable = true;
@@ -622,14 +608,10 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
                                                write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> ", struct_name, ident, struct_name).unwrap();
                                                types.write_c_type(w, &ref_type, Some(&gen_types), true);
                                                write!(w, " {{\n\tlet mut inner_val = &mut unsafe {{ &mut *this_ptr.inner }}.{};\n\t", ident).unwrap();
-                                               let local_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("inner_val", Span::call_site()), &ref_type, Some(&gen_types), true);
+                                               let local_var = types.write_to_c_conversion_new_var(w, &format_ident!("inner_val"), &ref_type, Some(&gen_types), true);
                                                if local_var { write!(w, "\n\t").unwrap(); }
                                                types.write_to_c_conversion_inline_prefix(w, &ref_type, Some(&gen_types), true);
-                                               if local_var {
-                                                       write!(w, "inner_val").unwrap();
-                                               } else {
-                                                       write!(w, "(*inner_val)").unwrap();
-                                               }
+                                               write!(w, "inner_val").unwrap();
                                                types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
                                                writeln!(w, "\n}}").unwrap();
                                        }
@@ -639,7 +621,7 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
                                                write!(w, "#[no_mangle]\npub extern \"C\" fn {}_set_{}(this_ptr: &mut {}, mut val: ", struct_name, ident, struct_name).unwrap();
                                                types.write_c_type(w, &field.ty, Some(&gen_types), false);
                                                write!(w, ") {{\n\t").unwrap();
-                                               let local_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("val", Span::call_site()), &field.ty, Some(&gen_types));
+                                               let local_var = types.write_from_c_conversion_new_var(w, &format_ident!("val"), &field.ty, Some(&gen_types));
                                                if local_var { write!(w, "\n\t").unwrap(); }
                                                write!(w, "unsafe {{ &mut *this_ptr.inner }}.{} = ", ident).unwrap();
                                                types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
@@ -662,8 +644,8 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
                        }
                        write!(w, ") -> {} {{\n\t", struct_name).unwrap();
                        for field in fields.named.iter() {
-                               let field_name = format!("{}_arg", field.ident.as_ref().unwrap());
-                               if types.write_from_c_conversion_new_var(w, &syn::Ident::new(&field_name, Span::call_site()), &field.ty, Some(&gen_types)) {
+                               let field_ident = format_ident!("{}_arg", field.ident.as_ref().unwrap());
+                               if types.write_from_c_conversion_new_var(w, &field_ident, &field.ty, Some(&gen_types)) {
                                        write!(w, "\n\t").unwrap();
                                }
                        }
@@ -697,7 +679,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
 
        if let syn::Type::Tuple(_) = &*i.self_ty {
                if types.understood_c_type(&*i.self_ty, None) {
-                       let mut gen_types = GenericTypes::new();
+                       let mut gen_types = GenericTypes::new(None);
                        if !gen_types.learn_generics(&i.generics, types) {
                                eprintln!("Not implementing anything for `impl (..)` due to not understood generics");
                                return;
@@ -724,7 +706,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                if p.qself.is_some() { unimplemented!(); }
                if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
                        if let Some(resolved_path) = types.maybe_resolve_non_ignored_ident(&ident) {
-                               let mut gen_types = GenericTypes::new();
+                               let mut gen_types = GenericTypes::new(Some((resolved_path.clone(), &p.path)));
                                if !gen_types.learn_generics(&i.generics, types) {
                                        eprintln!("Not implementing anything for impl {} due to not understood generics", ident);
                                        return;
@@ -976,6 +958,39 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                writeln!(w, "/// Creates a copy of the {}", ident).unwrap();
                                                writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", ident, ident, ident).unwrap();
                                                writeln!(w, "\torig.clone()").unwrap();
+                                               writeln!(w, "}}").unwrap();
+                                       } else if path_matches_nongeneric(&trait_path.1, &["FromStr"]) {
+                                               if let Some(container) = types.get_c_mangled_container_type(
+                                                               vec![&*i.self_ty, &syn::Type::Tuple(syn::TypeTuple { paren_token: Default::default(), elems: syn::punctuated::Punctuated::new() })],
+                                                               Some(&gen_types), "Result") {
+                                                       writeln!(w, "#[no_mangle]").unwrap();
+                                                       writeln!(w, "/// Read a {} object from a string", ident).unwrap();
+                                                       writeln!(w, "pub extern \"C\" fn {}_from_str(s: crate::c_types::Str) -> {} {{", ident, container).unwrap();
+                                                       writeln!(w, "\tmatch {}::from_str(s.into_str()) {{", resolved_path).unwrap();
+                                                       writeln!(w, "\t\tOk(r) => {{").unwrap();
+                                                       let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("r"), &*i.self_ty, Some(&gen_types), false);
+                                                       write!(w, "\t\t\tcrate::c_types::CResultTempl::ok(\n\t\t\t\t").unwrap();
+                                                       types.write_to_c_conversion_inline_prefix(w, &*i.self_ty, Some(&gen_types), false);
+                                                       write!(w, "{}r", if new_var { "local_" } else { "" }).unwrap();
+                                                       types.write_to_c_conversion_inline_suffix(w, &*i.self_ty, Some(&gen_types), false);
+                                                       writeln!(w, "\n\t\t\t)\n\t\t}},").unwrap();
+                                                       writeln!(w, "\t\tErr(e) => crate::c_types::CResultTempl::err(()),").unwrap();
+                                                       writeln!(w, "\t}}.into()\n}}").unwrap();
+                                               }
+                                       } else if path_matches_nongeneric(&trait_path.1, &["Display"]) {
+                                               writeln!(w, "#[no_mangle]").unwrap();
+                                               writeln!(w, "/// Get the string representation of a {} object", ident).unwrap();
+                                               writeln!(w, "pub extern \"C\" fn {}_to_str(o: &crate::{}) -> Str {{", ident, resolved_path).unwrap();
+
+                                               let self_ty = &i.self_ty;
+                                               let ref_type: syn::Type = syn::parse_quote!(&#self_ty);
+                                               let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("o"), &ref_type, Some(&gen_types));
+                                               write!(w, "\tformat!(\"{{}}\", ").unwrap();
+                                               types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
+                                               write!(w, "{}o", if new_var { "local_" } else { "" }).unwrap();
+                                               types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
+                                               writeln!(w, ").into()").unwrap();
+
                                                writeln!(w, "}}").unwrap();
                                        } else {
                                                //XXX: implement for other things like ToString
@@ -1010,18 +1025,30 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                        write_method_var_decl_body(w, &m.sig, "", types, Some(&meth_gen_types), false);
                                                                        let mut takes_self = false;
                                                                        let mut takes_mut_self = false;
+                                                                       let mut takes_owned_self = false;
                                                                        for inp in m.sig.inputs.iter() {
                                                                                if let syn::FnArg::Receiver(r) = inp {
                                                                                        takes_self = true;
                                                                                        if r.mutability.is_some() { takes_mut_self = true; }
+                                                                                       if r.reference.is_none() { takes_owned_self = true; }
                                                                                }
                                                                        }
-                                                                       if takes_mut_self {
-                                                                               write!(w, "unsafe {{ &mut (*(this_arg.inner as *mut native{})) }}.{}(", ident, m.sig.ident).unwrap();
-                                                                       } else if takes_self {
-                                                                               write!(w, "unsafe {{ &*this_arg.inner }}.{}(", m.sig.ident).unwrap();
-                                                                       } else {
+                                                                       if !takes_mut_self && !takes_self {
                                                                                write!(w, "{}::{}(", resolved_path, m.sig.ident).unwrap();
+                                                                       } else {
+                                                                               match &declared_type {
+                                                                                       DeclType::MirroredEnum => write!(w, "this_arg.to_native().{}(", m.sig.ident).unwrap(),
+                                                                                       DeclType::StructImported => {
+                                                                                               if takes_owned_self {
+                                                                                                       write!(w, "(*unsafe {{ Box::from_raw(this_arg.take_inner()) }}).{}(", m.sig.ident).unwrap();
+                                                                                               } else if takes_mut_self {
+                                                                                                       write!(w, "unsafe {{ &mut (*(this_arg.inner as *mut native{})) }}.{}(", ident, m.sig.ident).unwrap();
+                                                                                               } else {
+                                                                                                       write!(w, "unsafe {{ &*this_arg.inner }}.{}(", m.sig.ident).unwrap();
+                                                                                               }
+                                                                                       },
+                                                                                       _ => unimplemented!(),
+                                                                               }
                                                                        }
                                                                        write_method_call_params(w, &m.sig, "", types, Some(&meth_gen_types), &ret_type, false);
                                                                        writeln!(w, "\n}}\n").unwrap();
@@ -1110,9 +1137,8 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
        }
        writeln_docs(w, &e.attrs, "");
 
-       if e.generics.lt_token.is_some() {
-               unimplemented!();
-       }
+       let mut gen_types = GenericTypes::new(None);
+       assert!(gen_types.learn_generics(&e.generics, types));
 
        let mut needs_free = false;
 
@@ -1128,21 +1154,31 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
                                writeln_docs(w, &field.attrs, "\t\t");
                                write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
-                               types.write_c_type(w, &field.ty, None, false);
+                               types.write_c_type(w, &field.ty, Some(&gen_types), false);
                                writeln!(w, ",").unwrap();
                        }
                        write!(w, "\t}}").unwrap();
                } else if let syn::Fields::Unnamed(fields) = &var.fields {
-                       needs_free = true;
-                       write!(w, "(").unwrap();
-                       for (idx, field) in fields.unnamed.iter().enumerate() {
-                               if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
-                               types.write_c_type(w, &field.ty, None, false);
-                               if idx != fields.unnamed.len() - 1 {
-                                       write!(w, ",").unwrap();
+                       let mut empty_tuple_variant = false;
+                       if fields.unnamed.len() == 1 {
+                               let mut empty_check = Vec::new();
+                               types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false);
+                               if empty_check.is_empty() {
+                                       empty_tuple_variant = true;
+                               }
+                       }
+                       if !empty_tuple_variant {
+                               needs_free = true;
+                               write!(w, "(").unwrap();
+                               for (idx, field) in fields.unnamed.iter().enumerate() {
+                                       if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
+                                       types.write_c_type(w, &field.ty, Some(&gen_types), false);
+                                       if idx != fields.unnamed.len() - 1 {
+                                               write!(w, ",").unwrap();
+                                       }
                                }
+                               write!(w, ")").unwrap();
                        }
-                       write!(w, ")").unwrap();
                }
                if var.discriminant.is_some() { unimplemented!(); }
                writeln!(w, ",").unwrap();
@@ -1154,6 +1190,7 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                        writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap();
                        for var in e.variants.iter() {
                                write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap();
+                               let mut empty_tuple_variant = false;
                                if let syn::Fields::Named(fields) = &var.fields {
                                        write!(w, "{{").unwrap();
                                        for field in fields.named.iter() {
@@ -1162,12 +1199,21 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                        }
                                        write!(w, "}} ").unwrap();
                                } else if let syn::Fields::Unnamed(fields) = &var.fields {
-                                       write!(w, "(").unwrap();
-                                       for (idx, field) in fields.unnamed.iter().enumerate() {
-                                               if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
-                                               write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap();
+                                       if fields.unnamed.len() == 1 {
+                                               let mut empty_check = Vec::new();
+                                               types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false);
+                                               if empty_check.is_empty() {
+                                                       empty_tuple_variant = true;
+                                               }
+                                       }
+                                       if !empty_tuple_variant || $to_c {
+                                               write!(w, "(").unwrap();
+                                               for (idx, field) in fields.unnamed.iter().enumerate() {
+                                                       if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
+                                                       write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap();
+                                               }
+                                               write!(w, ") ").unwrap();
                                        }
-                                       write!(w, ") ").unwrap();
                                }
                                write!(w, "=>").unwrap();
 
@@ -1177,19 +1223,19 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                                let mut sink = ::std::io::sink();
                                                let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
                                                let new_var = if $to_c {
-                                                       types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, None, false)
+                                                       types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types), false)
                                                } else {
-                                                       types.write_from_c_conversion_new_var(&mut out, $field_ident, &$field.ty, None)
+                                                       types.write_from_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types))
                                                };
                                                if $ref || new_var {
                                                        if $ref {
                                                                write!(w, "let mut {}_nonref = (*{}).clone();\n\t\t\t\t", $field_ident, $field_ident).unwrap();
                                                                if new_var {
-                                                                       let nonref_ident = syn::Ident::new(&format!("{}_nonref", $field_ident), Span::call_site());
+                                                                       let nonref_ident = format_ident!("{}_nonref", $field_ident);
                                                                        if $to_c {
-                                                                               types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, None, false);
+                                                                               types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types), false);
                                                                        } else {
-                                                                               types.write_from_c_conversion_new_var(w, &nonref_ident, &$field.ty, None);
+                                                                               types.write_from_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types));
                                                                        }
                                                                        write!(w, "\n\t\t\t\t").unwrap();
                                                                }
@@ -1207,7 +1253,9 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                } else if let syn::Fields::Unnamed(fields) = &var.fields {
                                        write!(w, " {{\n\t\t\t\t").unwrap();
                                        for (idx, field) in fields.unnamed.iter().enumerate() {
-                                               handle_field_a!(field, &syn::Ident::new(&(('a' as u8 + idx as u8) as char).to_string(), Span::call_site()));
+                                               if !empty_tuple_variant {
+                                                       handle_field_a!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
+                                               }
                                        }
                                } else { write!(w, " ").unwrap(); }
 
@@ -1217,16 +1265,16 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                        ($field: expr, $field_ident: expr) => { {
                                                if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
                                                if $to_c {
-                                                       types.write_to_c_conversion_inline_prefix(w, &$field.ty, None, false);
+                                                       types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), false);
                                                } else {
-                                                       types.write_from_c_conversion_prefix(w, &$field.ty, None);
+                                                       types.write_from_c_conversion_prefix(w, &$field.ty, Some(&gen_types));
                                                }
                                                write!(w, "{}{}", $field_ident,
                                                        if $ref { "_nonref" } else { "" }).unwrap();
                                                if $to_c {
-                                                       types.write_to_c_conversion_inline_suffix(w, &$field.ty, None, false);
+                                                       types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), false);
                                                } else {
-                                                       types.write_from_c_conversion_suffix(w, &$field.ty, None);
+                                                       types.write_from_c_conversion_suffix(w, &$field.ty, Some(&gen_types));
                                                }
                                                write!(w, ",").unwrap();
                                        } }
@@ -1242,12 +1290,14 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
                                        writeln!(w, "\n\t\t\t\t}}").unwrap();
                                        write!(w, "\t\t\t}}").unwrap();
                                } else if let syn::Fields::Unnamed(fields) = &var.fields {
-                                       write!(w, " (").unwrap();
-                                       for (idx, field) in fields.unnamed.iter().enumerate() {
-                                               write!(w, "\n\t\t\t\t\t").unwrap();
-                                               handle_field_b!(field, &syn::Ident::new(&(('a' as u8 + idx as u8) as char).to_string(), Span::call_site()));
+                                       if !empty_tuple_variant || !$to_c {
+                                               write!(w, " (").unwrap();
+                                               for (idx, field) in fields.unnamed.iter().enumerate() {
+                                                       write!(w, "\n\t\t\t\t\t").unwrap();
+                                                       handle_field_b!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
+                                               }
+                                               writeln!(w, "\n\t\t\t\t)").unwrap();
                                        }
-                                       writeln!(w, "\n\t\t\t\t)").unwrap();
                                        write!(w, "\t\t\t}}").unwrap();
                                }
                                writeln!(w, ",").unwrap();
@@ -1281,7 +1331,7 @@ fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &
        }
        writeln_docs(w, &f.attrs, "");
 
-       let mut gen_types = GenericTypes::new();
+       let mut gen_types = GenericTypes::new(None);
        if !gen_types.learn_generics(&f.sig.generics, types) { return; }
 
        write!(w, "#[no_mangle]\npub extern \"C\" fn {}(", f.sig.ident).unwrap();
@@ -1297,11 +1347,41 @@ fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &
 // *** File/Crate Walking Logic ***
 // ********************************
 
+fn convert_priv_mod<'a, 'b: 'a, W: std::io::Write>(w: &mut W, libast: &'b FullLibraryAST, crate_types: &CrateTypes<'b>, out_dir: &str, mod_path: &str, module: &'b syn::ItemMod) {
+       // We want to ignore all items declared in this module (as they are not pub), but we still need
+       // to give the ImportResolver any use statements, so we copy them here.
+       let mut use_items = Vec::new();
+       for item in module.content.as_ref().unwrap().1.iter() {
+               if let syn::Item::Use(_) = item {
+                       use_items.push(item);
+               }
+       }
+       let import_resolver = ImportResolver::from_borrowed_items(mod_path.splitn(2, "::").next().unwrap(), &libast.dependencies, mod_path, &use_items);
+       let mut types = TypeResolver::new(mod_path, import_resolver, crate_types);
+
+       writeln!(w, "mod {} {{\n{}", module.ident, DEFAULT_IMPORTS).unwrap();
+       for item in module.content.as_ref().unwrap().1.iter() {
+               match item {
+                       syn::Item::Mod(m) => convert_priv_mod(w, libast, crate_types, out_dir, &format!("{}::{}", mod_path, module.ident), m),
+                       syn::Item::Impl(i) => {
+                               if let &syn::Type::Path(ref p) = &*i.self_ty {
+                                       if p.path.get_ident().is_some() {
+                                               writeln_impl(w, i, &mut types);
+                                       }
+                               }
+                       },
+                       _ => {},
+               }
+       }
+       writeln!(w, "}}").unwrap();
+}
+
 /// Do the Real Work of mapping an original file to C-callable wrappers. Creates a new file at
 /// `out_path` and fills it with wrapper structs/functions to allow calling the things in the AST
 /// at `module` from C.
-fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>, out_dir: &str, orig_crate: &str, header_file: &mut File, cpp_header_file: &mut File) {
+fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>, out_dir: &str, header_file: &mut File, cpp_header_file: &mut File) {
        for (module, astmod) in libast.modules.iter() {
+               let orig_crate = module.splitn(2, "::").next().unwrap();
                let ASTModule { ref attrs, ref items, ref submods } = astmod;
                assert_eq!(export_status(&attrs), ExportStatus::Export);
 
@@ -1340,11 +1420,12 @@ fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>
                        writeln!(out, "#![allow(unused_parens)]").unwrap();
                        writeln!(out, "#![allow(unused_unsafe)]").unwrap();
                        writeln!(out, "#![allow(unused_braces)]").unwrap();
-                       writeln!(out, "#![deny(missing_docs)]").unwrap();
+                       // TODO: We need to map deny(missing_docs) in the source crate(s)
+                       //writeln!(out, "#![deny(missing_docs)]").unwrap();
                        writeln!(out, "pub mod c_types;").unwrap();
                        writeln!(out, "pub mod bitcoin;").unwrap();
                } else {
-                       writeln!(out, "\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n").unwrap();
+                       writeln!(out, "{}", DEFAULT_IMPORTS).unwrap();
                }
 
                for m in submods {
@@ -1378,7 +1459,9 @@ fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>
                                                writeln_trait(&mut out, &t, &mut type_resolver, header_file, cpp_header_file);
                                        }
                                },
-                               syn::Item::Mod(_) => {}, // We don't have to do anything - the top loop handles these.
+                               syn::Item::Mod(m) => {
+                                       convert_priv_mod(&mut out, libast, crate_types, out_dir, &format!("{}::{}", module, m.ident), m);
+                               },
                                syn::Item::Const(c) => {
                                        // Re-export any primitive-type constants.
                                        if let syn::Visibility::Public(_) = c.vis {
@@ -1454,10 +1537,11 @@ fn walk_private_mod<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, modul
 }
 
 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
-fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, crate_types: &mut CrateTypes<'a>) {
+fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
        for (module, astmod) in ast_storage.modules.iter() {
                let ASTModule { ref attrs, ref items, submods: _ } = astmod;
                assert_eq!(export_status(&attrs), ExportStatus::Export);
+               let orig_crate = module.splitn(2, "::").next().unwrap();
                let import_resolver = ImportResolver::new(orig_crate, &ast_storage.dependencies, module, items);
 
                for item in items.iter() {
@@ -1503,20 +1587,17 @@ fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, crate_types:
                                                if process_alias {
                                                        match &*t.ty {
                                                                syn::Type::Path(p) => {
+                                                                       let t_ident = &t.ident;
+
                                                                        // If its a path with no generics, assume we don't map the aliased type and map it opaque
-                                                                       let mut segments = syn::punctuated::Punctuated::new();
-                                                                       segments.push(syn::PathSegment {
-                                                                               ident: t.ident.clone(),
-                                                                               arguments: syn::PathArguments::None,
-                                                                       });
-                                                                       let path_obj = syn::Path { leading_colon: None, segments };
+                                                                       let path_obj = parse_quote!(#t_ident);
                                                                        let args_obj = p.path.segments.last().unwrap().arguments.clone();
                                                                        match crate_types.reverse_alias_map.entry(import_resolver.maybe_resolve_path(&p.path, None).unwrap()) {
                                                                                hash_map::Entry::Occupied(mut e) => { e.get_mut().push((path_obj, args_obj)); },
                                                                                hash_map::Entry::Vacant(e) => { e.insert(vec![(path_obj, args_obj)]); },
                                                                        }
 
-                                                                       crate_types.opaques.insert(type_path.clone(), &t.ident);
+                                                                       crate_types.opaques.insert(type_path, t_ident);
                                                                },
                                                                _ => {
                                                                        crate_types.type_aliases.insert(type_path, import_resolver.resolve_imported_refs((*t.ty).clone()));
@@ -1573,17 +1654,17 @@ fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, crate_types:
 
 fn main() {
        let args: Vec<String> = env::args().collect();
-       if args.len() != 6 {
-               eprintln!("Usage: target/dir source_crate_name derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
+       if args.len() != 5 {
+               eprintln!("Usage: target/dir derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
                process::exit(1);
        }
 
        let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
-               .open(&args[3]).expect("Unable to open new header file");
+               .open(&args[2]).expect("Unable to open new header file");
        let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
-               .open(&args[4]).expect("Unable to open new header file");
+               .open(&args[3]).expect("Unable to open new header file");
        let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
-               .open(&args[5]).expect("Unable to open new header file");
+               .open(&args[4]).expect("Unable to open new header file");
 
        writeln!(header_file, "#if defined(__GNUC__)").unwrap();
        writeln!(header_file, "#define MUST_USE_STRUCT __attribute__((warn_unused))").unwrap();
@@ -1609,10 +1690,10 @@ fn main() {
        // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
        // when parsing other file ASTs...
        let mut libtypes = CrateTypes::new(&mut derived_templates, &libast);
-       walk_ast(&libast, &args[2], &mut libtypes);
+       walk_ast(&libast, &mut libtypes);
 
        // ... finally, do the actual file conversion/mapping, writing out types as we go.
-       convert_file(&libast, &libtypes, &args[1], &args[2], &mut header_file, &mut cpp_header_file);
+       convert_file(&libast, &libtypes, &args[1], &mut header_file, &mut cpp_header_file);
 
        // For container templates which we created while walking the crate, make sure we add C++
        // mapped types so that C++ users can utilize the auto-destructors available.