Merge pull request #51 from TheBlueMatt/main
[ldk-c-bindings] / c-bindings-gen / src / blocks.rs
index b6622617731fb14947cfe00e3f3f41582307a21b..b2f952be5fa1cb3fdcb6f51a6d677d7680f59d60 100644 (file)
 
 use std::fs::File;
 use std::io::Write;
-use proc_macro2::{TokenTree, Span};
+
+use proc_macro2::TokenTree;
+use quote::format_ident;
 
 use crate::types::*;
 
 /// Writes out a C++ wrapper class for the given type, which contains various utilities to access
 /// the underlying C-mapped type safely avoiding some common memory management issues by handling
 /// resource-freeing and prevending accidental raw copies.
-pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool) {
+pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool, trait_methods: Option<Vec<(String, String)>>) {
        writeln!(cpp_header_file, "class {} {{", ty).unwrap();
        writeln!(cpp_header_file, "private:").unwrap();
        writeln!(cpp_header_file, "\tLDK{} self;", ty).unwrap();
@@ -37,20 +39,33 @@ pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: b
        writeln!(cpp_header_file, "\tLDK{}* operator ->() {{ return &self; }}", ty).unwrap();
        writeln!(cpp_header_file, "\tconst LDK{}* operator &() const {{ return &self; }}", ty).unwrap();
        writeln!(cpp_header_file, "\tconst LDK{}* operator ->() const {{ return &self; }}", ty).unwrap();
+       if let Some(methods) = trait_methods {
+               for (meth_name, meth_docs) in methods {
+                       cpp_header_file.write_all(meth_docs.as_bytes()).unwrap();
+                       // Note that we have zero logic to print C/C__ code for a given function. Instead, we
+                       // simply use sed to replace the following in genbindings.sh
+                       writeln!(cpp_header_file, "XXX {} {}", ty, meth_name).unwrap();
+               }
+       }
        writeln!(cpp_header_file, "}};").unwrap();
 }
 
 /// Writes out a C-callable concrete Result<A, B> struct and utility methods
 pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str, ok_type: &str, err_type: &str, clonable: bool) {
        writeln!(w, "#[repr(C)]").unwrap();
+       writeln!(w, "/// The contents of {}", mangled_container).unwrap();
        writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap();
        if ok_type != "()" {
+               writeln!(w, "\t/// A pointer to the contents in the success state.").unwrap();
+               writeln!(w, "\t/// Reading from this pointer when `result_ok` is not set is undefined.").unwrap();
                writeln!(w, "\tpub result: *mut {},", ok_type).unwrap();
        } else {
                writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the OK variant").unwrap();
                writeln!(w, "\tpub result: *mut std::ffi::c_void,").unwrap();
        }
        if err_type != "()" {
+               writeln!(w, "\t/// A pointer to the contents in the error state.").unwrap();
+               writeln!(w, "\t/// Reading from this pointer when `result_ok` is set is undefined.").unwrap();
                writeln!(w, "\tpub err: *mut {},", err_type).unwrap();
        } else {
                writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the Err variant").unwrap();
@@ -58,15 +73,23 @@ pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
        }
        writeln!(w, "}}").unwrap();
        writeln!(w, "#[repr(C)]").unwrap();
+       writeln!(w, "/// A {} represents the result of a fallible operation,", mangled_container).unwrap();
+       writeln!(w, "/// containing a {} on success and a {} on failure.", ok_type, err_type).unwrap();
+       writeln!(w, "/// `result_ok` indicates the overall state, and the contents are provided via `contents`.").unwrap();
        writeln!(w, "pub struct {} {{", mangled_container).unwrap();
+       writeln!(w, "\t/// The contents of this {}, accessible via either", mangled_container).unwrap();
+       writeln!(w, "\t/// `err` or `result` depending on the state of `result_ok`.").unwrap();
        writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap();
+       writeln!(w, "\t/// Whether this {} represents a success state.", mangled_container).unwrap();
        writeln!(w, "\tpub result_ok: bool,").unwrap();
        writeln!(w, "}}").unwrap();
 
        writeln!(w, "#[no_mangle]").unwrap();
        if ok_type != "()" {
+               writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
                writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap();
        } else {
+               writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
                writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap();
        }
        writeln!(w, "\t{} {{", mangled_container).unwrap();
@@ -83,8 +106,10 @@ pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
 
        writeln!(w, "#[no_mangle]").unwrap();
        if err_type != "()" {
+               writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
                writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap();
        } else {
+               writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
                writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap();
        }
        writeln!(w, "\t{} {{", mangled_container).unwrap();
@@ -99,7 +124,14 @@ pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
        writeln!(w, "\t}}").unwrap();
        writeln!(w, "}}").unwrap();
 
+       writeln!(w, "/// Checks if the given object is currently in the success state").unwrap();
        writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "pub extern \"C\" fn {}_is_ok(o: &{}) -> bool {{", mangled_container, mangled_container).unwrap();
+       writeln!(w, "\to.result_ok").unwrap();
+       writeln!(w, "}}").unwrap();
+
+       writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
        writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
        writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
        writeln!(w, "\tfn drop(&mut self) {{").unwrap();
@@ -119,12 +151,8 @@ pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
        writeln!(w, "\t}}").unwrap();
        writeln!(w, "}}").unwrap();
 
-       // TODO: Templates should use () now that they can, too
-       let templ_ok_type = if ok_type != "()" { ok_type } else { "u8" };
-       let templ_err_type = if err_type != "()" { err_type } else { "u8" };
-
-       writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", templ_ok_type, templ_err_type, mangled_container).unwrap();
-       writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", templ_ok_type, templ_err_type).unwrap();
+       writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", ok_type, err_type, mangled_container).unwrap();
+       writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", ok_type, err_type).unwrap();
        writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
        if ok_type != "()" {
                writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
@@ -176,15 +204,22 @@ pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
                writeln!(w, "\t}}").unwrap();
                writeln!(w, "}}").unwrap();
                writeln!(w, "#[no_mangle]").unwrap();
-               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
+               writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
+               writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
+               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
        }
 }
 
 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
        writeln!(w, "#[repr(C)]").unwrap();
+       writeln!(w, "/// A dynamically-allocated array of {}s of arbitrary size.", inner_type).unwrap();
+       writeln!(w, "/// This corresponds to std::vector in C++").unwrap();
        writeln!(w, "pub struct {} {{", mangled_container).unwrap();
+       writeln!(w, "\t/// The elements in the array.").unwrap();
+       writeln!(w, "\t/// If datalen is non-0 this must be a valid, non-NULL pointer allocated by malloc().").unwrap();
        writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
+       writeln!(w, "\t/// The number of elements pointed to by `data`.").unwrap();
        writeln!(w, "\tpub datalen: usize").unwrap();
        writeln!(w, "}}").unwrap();
 
@@ -210,6 +245,7 @@ pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, in
        writeln!(w, "}}").unwrap();
 
        writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Frees the buffer pointed to by `data` if `datalen` is non-0.").unwrap();
        writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
        writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
        writeln!(w, "\tfn drop(&mut self) {{").unwrap();
@@ -232,8 +268,10 @@ pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, in
 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str, types: &[String], clonable: bool) {
        writeln!(w, "#[repr(C)]").unwrap();
+       writeln!(w, "/// A tuple of {} elements. See the individual fields for the types contained.", types.len()).unwrap();
        writeln!(w, "pub struct {} {{", mangled_container).unwrap();
        for (idx, ty) in types.iter().enumerate() {
+               writeln!(w, "\t/// The element at position {}", idx).unwrap();
                writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
        }
        writeln!(w, "}}").unwrap();
@@ -269,15 +307,18 @@ pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
                writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
                writeln!(w, "\t\tSelf {{").unwrap();
                for idx in 0..types.len() {
-                       writeln!(w, "\t\t\t{}: self.{}.clone(),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
+                       writeln!(w, "\t\t\t{}: Clone::clone(&self.{}),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
                }
                writeln!(w, "\t\t}}").unwrap();
                writeln!(w, "\t}}").unwrap();
                writeln!(w, "}}").unwrap();
                writeln!(w, "#[no_mangle]").unwrap();
-               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
+               writeln!(w, "/// Creates a new tuple which has the same data as `orig`").unwrap();
+               writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
+               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
        }
 
+       writeln!(w, "/// Creates a new {} from the contained elements.", mangled_container).unwrap();
        write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
        for (idx, gen) in types.iter().enumerate() {
                write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
@@ -292,6 +333,7 @@ pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
        writeln!(w, "}}\n}}\n").unwrap();
 
        writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
        writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 }
 
@@ -301,30 +343,88 @@ pub fn write_option_block<W: std::io::Write>(w: &mut W, mangled_container: &str,
        if clonable {
                writeln!(w, "#[derive(Clone)]").unwrap();
        }
+       writeln!(w, "/// An enum which can either contain a {} or not", inner_type).unwrap();
        writeln!(w, "pub enum {} {{", mangled_container).unwrap();
-       writeln!(w, "\tSome({}),", inner_type).unwrap();
+       writeln!(w, "\t/// When we're in this state, this {} contains a {}", mangled_container, inner_type).unwrap();
+       if inner_type != "" {
+               writeln!(w, "\tSome({}),", inner_type).unwrap();
+       } else {
+               writeln!(w, "\tSome,").unwrap();
+       }
+       writeln!(w, "\t/// When we're in this state, this {} contains nothing", mangled_container).unwrap();
        writeln!(w, "\tNone").unwrap();
        writeln!(w, "}}").unwrap();
 
        writeln!(w, "impl {} {{", mangled_container).unwrap();
        writeln!(w, "\t#[allow(unused)] pub(crate) fn is_some(&self) -> bool {{").unwrap();
-       writeln!(w, "\t\tif let Self::Some(_) = self {{ true }} else {{ false }}").unwrap();
+       writeln!(w, "\t\tif let Self::None = self {{ false }} else {{ true }}").unwrap();
        writeln!(w, "\t}}").unwrap();
-       writeln!(w, "\t#[allow(unused)] pub(crate) fn take(mut self) -> {} {{", inner_type).unwrap();
-       writeln!(w, "\t\tif let Self::Some(v) = self {{ v }} else {{ unreachable!() }}").unwrap();
+       writeln!(w, "\t#[allow(unused)] pub(crate) fn is_none(&self) -> bool {{").unwrap();
+       writeln!(w, "\t\t!self.is_some()").unwrap();
        writeln!(w, "\t}}").unwrap();
+       if inner_type != "" {
+               writeln!(w, "\t#[allow(unused)] pub(crate) fn take(mut self) -> {} {{", inner_type).unwrap();
+               writeln!(w, "\t\tif let Self::Some(v) = self {{ v }} else {{ unreachable!() }}").unwrap();
+               writeln!(w, "\t}}").unwrap();
+       }
+       writeln!(w, "}}").unwrap();
+
+       writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Constructs a new {} containing a {}", mangled_container, inner_type).unwrap();
+       if inner_type != "" {
+               writeln!(w, "pub extern \"C\" fn {}_some(o: {}) -> {} {{", mangled_container, inner_type, mangled_container).unwrap();
+               writeln!(w, "\t{}::Some(o)", mangled_container).unwrap();
+       } else {
+               writeln!(w, "pub extern \"C\" fn {}_some() -> {} {{", mangled_container, mangled_container).unwrap();
+               writeln!(w, "\t{}::Some", mangled_container).unwrap();
+       }
        writeln!(w, "}}").unwrap();
 
        writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Constructs a new {} containing nothing", mangled_container).unwrap();
+       writeln!(w, "pub extern \"C\" fn {}_none() -> {} {{", mangled_container, mangled_container).unwrap();
+       writeln!(w, "\t{}::None", mangled_container).unwrap();
+       writeln!(w, "}}").unwrap();
+
+       writeln!(w, "#[no_mangle]").unwrap();
+       writeln!(w, "/// Frees any resources associated with the {}, if we are in the Some state", inner_type).unwrap();
        writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
        if clonable {
                writeln!(w, "#[no_mangle]").unwrap();
-               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
+               writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
+               writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
+               writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
        }
 }
 
+/// Prints the docs from a given attribute list unless its tagged no export
+pub fn writeln_fn_docs<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, args: I, ret: &syn::ReturnType) where I: Iterator<Item = &'a syn::FnArg> {
+       writeln_docs_impl(w, attrs, prefix, Some((types, generics,
+               args.filter_map(|arg| if let syn::FnArg::Typed(ty) = arg {
+                               if let syn::Pat::Ident(id) = &*ty.pat {
+                                       Some((id.ident.to_string(), &*ty.ty))
+                               } else { unimplemented!() }
+                       } else { None }),
+               if let syn::ReturnType::Type(_, ty) = ret { Some(&**ty) } else { None },
+               None
+       )));
+}
+
 /// Prints the docs from a given attribute list unless its tagged no export
 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
+       writeln_docs_impl(w, attrs, prefix, None::<(_, _, std::vec::Drain<'_, (String, &syn::Type)>, _, _)>);
+}
+
+pub fn writeln_arg_docs<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, args: I, ret: Option<&syn::Type>) where I: Iterator<Item = (String, &'a syn::Type)> {
+       writeln_docs_impl(w, attrs, prefix, Some((types, generics, args, ret, None)))
+}
+
+pub fn writeln_field_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, field: &syn::Type) {
+       writeln_docs_impl(w, attrs, prefix, Some((types, generics, vec![].drain(..), None, Some(field))))
+}
+
+/// Prints the docs from a given attribute list unless its tagged no export
+fn writeln_docs_impl<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, method_args_ret: Option<(&mut TypeResolver, Option<&GenericTypes>, I, Option<&syn::Type>, Option<&syn::Type>)>) where I: Iterator<Item = (String, &'a syn::Type)> {
        for attr in attrs.iter() {
                let tokens_clone = attr.tokens.clone();
                let mut token_iter = tokens_clone.into_iter();
@@ -360,6 +460,51 @@ pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], pref
                        },
                }
        }
+       if let Some((types, generics, inp, outp, field)) = method_args_ret {
+               let mut nullable_found = false;
+               for (name, inp) in inp {
+                       if types.skip_arg(inp, generics) { continue; }
+                       if if let syn::Type::Reference(syn::TypeReference { elem, .. }) = inp {
+                               if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
+                                       types.is_path_transparent_container(path, generics, true)
+                               } else { false }
+                       } else if let syn::Type::Path(syn::TypePath { ref path, .. }) = inp {
+                               types.is_path_transparent_container(path, generics, true)
+                       } else { false } {
+                               // Note downstream clients match this text exactly so any changes may require
+                               // changes in the Java and Swift bindings, at least.
+                               if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
+                               nullable_found = true;
+                               writeln!(w, "{}/// Note that {} (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix, name).unwrap();
+                       }
+               }
+               if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = outp {
+                       if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
+                               types.is_path_transparent_container(path, generics, true)
+                       } else { false }
+               } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = outp {
+                       types.is_path_transparent_container(path, generics, true)
+               } else { false } {
+                       // Note downstream clients match this text exactly so any changes may require
+                       // changes in the Java and Swift bindings, at least.
+                       if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
+                       nullable_found = true;
+                       writeln!(w, "{}/// Note that the return value (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
+               }
+               if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = field {
+                       if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
+                               types.is_path_transparent_container(path, generics, true)
+                       } else { false }
+               } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = field {
+                       types.is_path_transparent_container(path, generics, true)
+               } else { false } {
+                       // Note downstream clients match this text exactly so any changes may require
+                       // changes in the Java and Swift bindings, at least.
+                       if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
+                       writeln!(w, "{}/// Note that this (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
+               }
+       }
+
 }
 
 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
@@ -392,14 +537,16 @@ pub fn write_method_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, t
        for inp in sig.inputs.iter() {
                match inp {
                        syn::FnArg::Receiver(recv) => {
-                               if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
-                               write!(w, "this_arg: {}{}",
-                                       match (self_ptr, recv.mutability.is_some()) {
-                                               (true, true) => "*mut ",
-                                               (true, false) => "*const ",
-                                               (false, true) => "&mut ",
-                                               (false, false) => "&",
-                                       }, this_param).unwrap();
+                               if !recv.attrs.is_empty() { unimplemented!(); }
+                               write!(w, "{}this_arg: {}{}", if recv.reference.is_none() { "mut " } else { "" },
+                                       if recv.reference.is_some() {
+                                               match (self_ptr, recv.mutability.is_some()) {
+                                                       (true, true) => "*mut ",
+                                                       (true, false) => "*const ",
+                                                       (false, true) => "&mut ",
+                                                       (false, false) => "&",
+                                               }
+                                       } else { "" }, this_param).unwrap();
                                assert!(first_arg);
                                first_arg = false;
                        },
@@ -438,12 +585,7 @@ pub fn write_method_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, t
                                        return;
                                }
                        }
-                       if let syn::Type::Reference(r) = &**rtype {
-                               // We can't return a reference, cause we allocate things on the stack.
-                               types.write_c_type(w, &*r.elem, generics, true);
-                       } else {
-                               types.write_c_type(w, &*rtype, generics, true);
-                       }
+                       types.write_c_type(w, &*rtype, generics, true);
                },
                _ => {},
        }
@@ -454,7 +596,7 @@ pub fn write_method_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, t
 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 /// parameters we mapped to/from C here.
 pub fn write_method_var_decl_body<W: std::io::Write>(w: &mut W, sig: &syn::Signature, extra_indent: &str, types: &TypeResolver, generics: Option<&GenericTypes>, to_c: bool) {
-       let mut num_unused = 0;
+       let mut num_unused = 0u32;
        for inp in sig.inputs.iter() {
                match inp {
                        syn::FnArg::Receiver(_) => {},
@@ -483,7 +625,7 @@ pub fn write_method_var_decl_body<W: std::io::Write>(w: &mut W, sig: &syn::Signa
                                        },
                                        syn::Pat::Wild(w) => {
                                                if !w.attrs.is_empty() { unimplemented!(); }
-                                               write_new_var!(syn::Ident::new(&format!("unused_{}", num_unused), Span::call_site()), *arg.ty);
+                                               write_new_var!(format_ident!("unused_{}", num_unused), *arg.ty);
                                                num_unused += 1;
                                        },
                                        _ => unimplemented!(),
@@ -511,8 +653,9 @@ pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signatu
        for inp in sig.inputs.iter() {
                match inp {
                        syn::FnArg::Receiver(recv) => {
-                               if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
+                               if !recv.attrs.is_empty() { unimplemented!(); }
                                if to_c {
+                                       if recv.reference.is_none() { unimplemented!(); }
                                        write!(w, "self.this_arg").unwrap();
                                        first_arg = false;
                                }
@@ -574,9 +717,9 @@ pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signatu
                                write!(w, "ret").unwrap();
                        } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
                                // If we're returning "Self" (and not "Self::X"), just do it manually
-                               write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
+                               write!(w, "{} {{ inner: ObjOps::heap_alloc(ret), is_owned: true }}", this_type).unwrap();
                        } else if to_c {
-                               let new_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), rtype, generics);
+                               let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("ret"), rtype, generics);
                                if new_var {
                                        write!(w, "\n\t{}", extra_indent).unwrap();
                                }
@@ -584,13 +727,12 @@ pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signatu
                                write!(w, "ret").unwrap();
                                types.write_from_c_conversion_suffix(w, &*rtype, generics);
                        } else {
-                               let ret_returned = if let syn::Type::Reference(_) = &**rtype { true } else { false };
-                               let new_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), &rtype, generics, true);
+                               let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("ret"), &rtype, generics, true);
                                if new_var {
                                        write!(w, "\n\t{}", extra_indent).unwrap();
                                }
                                types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
-                               write!(w, "{}ret", if ret_returned && !new_var { "*" } else { "" }).unwrap();
+                               write!(w, "ret").unwrap();
                                types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
                        }
                }
@@ -601,24 +743,16 @@ pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signatu
 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 /// greater-than symbols, if any generic parameters are defined.
 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
-       let mut gen_types = GenericTypes::new();
+       let mut gen_types = GenericTypes::new(None);
        assert!(gen_types.learn_generics(generics, types));
        if !generics.params.is_empty() {
                write!(w, "<").unwrap();
                for (idx, generic) in generics.params.iter().enumerate() {
                        match generic {
                                syn::GenericParam::Type(type_param) => {
-                                       let mut printed_param = false;
-                                       for bound in type_param.bounds.iter() {
-                                               if let syn::TypeParamBound::Trait(trait_bound) = bound {
-                                                       assert_simple_bound(&trait_bound);
-                                                       write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
-                                                       if printed_param {
-                                                               unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
-                                                       }
-                                                       printed_param = true;
-                                               }
-                                       }
+                                       write!(w, "{}", if idx != 0 { ", " } else { "" }).unwrap();
+                                       let type_ident = &type_param.ident;
+                                       types.write_c_type_in_generic_param(w, &syn::parse_quote!(#type_ident), Some(&gen_types), false);
                                },
                                syn::GenericParam::Lifetime(lt) => {
                                        if concrete_lifetimes {
@@ -634,4 +768,20 @@ pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generi
        }
 }
 
-
+pub fn maybe_write_lifetime_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver) {
+       let mut gen_types = GenericTypes::new(None);
+       assert!(gen_types.learn_generics(generics, types));
+       if generics.params.iter().any(|param| if let syn::GenericParam::Lifetime(_) = param { true } else { false }) {
+               write!(w, "<").unwrap();
+               for (idx, generic) in generics.params.iter().enumerate() {
+                       match generic {
+                               syn::GenericParam::Type(_) => {},
+                               syn::GenericParam::Lifetime(lt) => {
+                                       write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
+                               },
+                               _ => unimplemented!(),
+                       }
+               }
+               write!(w, ">").unwrap();
+       }
+}