From c5c2d464ba56deb6ce6a32df14adecebcbdb07cc Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Mon, 4 Jan 2021 17:29:25 -0500 Subject: [PATCH] [bindings] Concretize Result types without type aliasing While the type aliasing trick works great for cbindgen, wasm_bindgen doesn't support it and requires fully-concrete types. In order to better support wasm_bindgen in the future, we do so here, adding a function which manually writes out almost the exact thing which was templated previously in concrete form. As a nice side-effect, we no longer have to allocate and free a u8 for generic parameters which were `()` (though we still do in some conversion functions, which we can get rid of when we similarly concretize all generics fully). --- c-bindings-gen/src/blocks.rs | 140 ++++++++++++++++++++++++ c-bindings-gen/src/types.rs | 122 +++++++++++---------- lightning-c-bindings/src/c_types/mod.rs | 13 +-- 3 files changed, 211 insertions(+), 64 deletions(-) diff --git a/c-bindings-gen/src/blocks.rs b/c-bindings-gen/src/blocks.rs index 107c72b3d..9ae0dab2e 100644 --- a/c-bindings-gen/src/blocks.rs +++ b/c-bindings-gen/src/blocks.rs @@ -32,6 +32,146 @@ pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: b writeln!(cpp_header_file, "}};").unwrap(); } +/// Writes out a C-callable concrete Result struct and utility methods +pub fn write_result_block(w: &mut W, mangled_container: &str, ok_type: &str, err_type: &str, clonable: bool) { + writeln!(w, "#[repr(C)]").unwrap(); + writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap(); + if ok_type != "()" { + 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, "\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(); + writeln!(w, "\tpub err: *mut std::ffi::c_void,").unwrap(); + } + writeln!(w, "}}").unwrap(); + writeln!(w, "#[repr(C)]").unwrap(); + writeln!(w, "pub struct {} {{", mangled_container).unwrap(); + writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap(); + writeln!(w, "\tpub result_ok: bool,").unwrap(); + writeln!(w, "}}").unwrap(); + + writeln!(w, "#[no_mangle]").unwrap(); + if ok_type != "()" { + writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap(); + } else { + writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap(); + } + writeln!(w, "\t{} {{", mangled_container).unwrap(); + writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap(); + if ok_type != "()" { + writeln!(w, "\t\t\tresult: Box::into_raw(Box::new(o)),").unwrap(); + } else { + writeln!(w, "\t\t\tresult: std::ptr::null_mut(),").unwrap(); + } + writeln!(w, "\t\t}},").unwrap(); + writeln!(w, "\t\tresult_ok: true,").unwrap(); + writeln!(w, "\t}}").unwrap(); + writeln!(w, "}}").unwrap(); + + writeln!(w, "#[no_mangle]").unwrap(); + if err_type != "()" { + writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap(); + } else { + writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap(); + } + writeln!(w, "\t{} {{", mangled_container).unwrap(); + writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap(); + if err_type != "()" { + writeln!(w, "\t\t\terr: Box::into_raw(Box::new(e)),").unwrap(); + } else { + writeln!(w, "\t\t\terr: std::ptr::null_mut(),").unwrap(); + } + writeln!(w, "\t\t}},").unwrap(); + writeln!(w, "\t\tresult_ok: false,").unwrap(); + writeln!(w, "\t}}").unwrap(); + writeln!(w, "}}").unwrap(); + + writeln!(w, "#[no_mangle]").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(); + writeln!(w, "\t\tif self.result_ok {{").unwrap(); + if ok_type != "()" { + writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap(); + writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap(); + writeln!(w, "\t\t\t}}").unwrap(); + } + writeln!(w, "\t\t}} else {{").unwrap(); + if err_type != "()" { + writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap(); + writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap(); + writeln!(w, "\t\t\t}}").unwrap(); + } + writeln!(w, "\t\t}}").unwrap(); + 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> 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, "\t\tlet contents = if o.result_ok {{").unwrap(); + if ok_type != "()" { + writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap(); + writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap(); + writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap(); + } else { + writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap(); + writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap(); + writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap(); + } + writeln!(w, "\t\t}} else {{").unwrap(); + if err_type != "()" { + writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap(); + writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap(); + writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap(); + } else { + writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap(); + writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap(); + writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap(); + } + writeln!(w, "\t\t}};").unwrap(); + writeln!(w, "\t\tSelf {{").unwrap(); + writeln!(w, "\t\t\tcontents,").unwrap(); + writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap(); + writeln!(w, "\t\t}}").unwrap(); + writeln!(w, "\t}}").unwrap(); + writeln!(w, "}}").unwrap(); + + if clonable { + writeln!(w, "impl Clone for {} {{", mangled_container).unwrap(); + writeln!(w, "\tfn clone(&self) -> Self {{").unwrap(); + writeln!(w, "\t\tif self.result_ok {{").unwrap(); + writeln!(w, "\t\t\tSelf {{ result_ok: true, contents: {}Ptr {{", mangled_container).unwrap(); + if ok_type != "()" { + writeln!(w, "\t\t\t\tresult: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.result }})))", ok_type).unwrap(); + } else { + writeln!(w, "\t\t\t\tresult: std::ptr::null_mut()").unwrap(); + } + writeln!(w, "\t\t\t}} }}").unwrap(); + writeln!(w, "\t\t}} else {{").unwrap(); + writeln!(w, "\t\t\tSelf {{ result_ok: false, contents: {}Ptr {{", mangled_container).unwrap(); + if err_type != "()" { + writeln!(w, "\t\t\t\terr: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.err }})))", err_type).unwrap(); + } else { + writeln!(w, "\t\t\t\terr: std::ptr::null_mut()").unwrap(); + } + writeln!(w, "\t\t\t}} }}").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(); + } +} + /// Prints the docs from a given attribute list unless its tagged no export pub fn writeln_docs(w: &mut W, attrs: &[syn::Attribute], prefix: &str) { for attr in attrs.iter() { diff --git a/c-bindings-gen/src/types.rs b/c-bindings-gen/src/types.rs index 22f1d9e5a..7e781a03e 100644 --- a/c-bindings-gen/src/types.rs +++ b/c-bindings-gen/src/types.rs @@ -3,6 +3,8 @@ use std::fs::File; use std::io::Write; use std::hash; +use crate::blocks::*; + use proc_macro2::{TokenTree, Span}; // The following utils are used purely to build our known types maps - they break down all the @@ -789,8 +791,8 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> { "Result" if !is_ref => { Some(("match ", vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()), - ("), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())], - ") }")) + (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())], + ").into() }")) }, "Vec" if !is_ref => { Some(("Vec::new(); for item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }")) @@ -1757,43 +1759,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> { // ****************************************************** fn write_template_constructor(&mut self, w: &mut W, container_type: &str, mangled_container: &str, args: &Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool { - if container_type == "Result" { - assert_eq!(args.len(), 2); - macro_rules! write_fn { - ($call: expr) => { { - writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}() -> {} {{", mangled_container, $call, mangled_container).unwrap(); - writeln!(w, "\t{}::CResultTempl::{}(0)\n}}\n", Self::container_templ_path(), $call).unwrap(); - } } - } - macro_rules! write_alias { - ($call: expr, $item: expr) => { { - write!(w, "#[no_mangle]\npub static {}_{}: extern \"C\" fn (", mangled_container, $call).unwrap(); - if let syn::Type::Path(syn::TypePath { path, .. }) = $item { - let resolved = self.resolve_path(path, generics); - if self.is_known_container(&resolved, is_ref) || self.is_transparent_container(&resolved, is_ref) { - self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(path), generics, - &format!("{}", single_ident_generic_path_to_ident(path).unwrap()), is_ref, false, false, false); - } else { - self.write_template_generics(w, &mut [$item].iter().map(|t| *t), generics, is_ref, true); - } - } else if let syn::Type::Tuple(syn::TypeTuple { elems, .. }) = $item { - self.write_c_mangled_container_path_intern(w, elems.iter().collect(), generics, - &format!("{}Tuple", elems.len()), is_ref, false, false, false); - } else { unimplemented!(); } - write!(w, ") -> {} =\n\t{}::CResultTempl::<", mangled_container, Self::container_templ_path()).unwrap(); - self.write_template_generics(w, &mut args.iter().map(|t| *t), generics, is_ref, true); - writeln!(w, ">::{};\n", $call).unwrap(); - } } - } - match args[0] { - syn::Type::Tuple(t) if t.elems.is_empty() => write_fn!("ok"), - _ => write_alias!("ok", args[0]), - } - match args[1] { - syn::Type::Tuple(t) if t.elems.is_empty() => write_fn!("err"), - _ => write_alias!("err", args[1]), - } - } else if container_type.ends_with("Tuple") { + if container_type.ends_with("Tuple") { write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap(); for (idx, gen) in args.iter().enumerate() { write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap(); @@ -1811,7 +1777,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> { true } - fn write_template_generics<'b, W: std::io::Write>(&self, w: &mut W, args: &mut dyn Iterator, generics: Option<&GenericTypes>, is_ref: bool, in_crate: bool) { + fn write_template_generics<'b, W: std::io::Write>(&mut self, w: &mut W, args: &mut dyn Iterator, generics: Option<&GenericTypes>, is_ref: bool, in_crate: bool) { for (idx, t) in args.enumerate() { if idx != 0 { write!(w, ", ").unwrap(); @@ -1830,14 +1796,24 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> { write!(w, "{}", resolved_generic).unwrap(); } else if let Some(c_type) = self.c_type_from_path(&resolved_generic, is_ref, false) { if self.is_known_container(&resolved_generic, is_ref) { + if resolved_generic == "Result" { + let mut inner_args = Vec::new(); + if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments { + for arg in args.args.iter() { + if let syn::GenericArgument::Type(t) = arg { inner_args.push(t) } else { unimplemented!() }; + } + } else { unimplemented!(); } + self.write_c_mangled_container_path(w, inner_args, generics, &resolved_generic, is_ref, false, false); + } else { write!(w, "{}::C{}Templ<", Self::container_templ_path(), single_ident_generic_path_to_ident(&p_arg.path).unwrap()).unwrap(); - assert_eq!(p_arg.path.segments.len(), 1); - if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments { - self.write_template_generics(w, &mut args.args.iter().map(|gen| - if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }), - generics, is_ref, in_crate); - } else { unimplemented!(); } - write!(w, ">").unwrap(); + assert_eq!(p_arg.path.segments.len(), 1); + if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments { + self.write_template_generics(w, &mut args.args.iter().map(|gen| + if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }), + generics, is_ref, in_crate); + } else { unimplemented!(); } + write!(w, ">").unwrap(); + } } else if resolved_generic == "Option" { if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments { self.write_template_generics(w, &mut args.args.iter().map(|gen| @@ -1891,18 +1867,50 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> { if !self.crate_types.templates_defined.get(&mangled_container).is_some() { let mut created_container: Vec = Vec::new(); - write!(&mut created_container, "pub type {} = ", mangled_container).unwrap(); - write!(&mut created_container, "{}::C{}Templ<", Self::container_templ_path(), container_type).unwrap(); - self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true); - writeln!(&mut created_container, ">;").unwrap(); + if container_type == "Result" { + let mut a_ty: Vec = Vec::new(); + if let syn::Type::Tuple(tup) = args.iter().next().unwrap() { + if tup.elems.is_empty() { + write!(&mut a_ty, "()").unwrap(); + } else { + self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref, true); + } + } else { + self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref, true); + } + + let mut b_ty: Vec = Vec::new(); + if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() { + if tup.elems.is_empty() { + write!(&mut b_ty, "()").unwrap(); + } else { + self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref, true); + } + } else { + self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref, true); + } + + let ok_str = String::from_utf8(a_ty).unwrap(); + let err_str = String::from_utf8(b_ty).unwrap(); + let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str); + write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable); + if is_clonable { + self.crate_types.clonable_types.insert(Self::generated_container_path().to_owned() + "::" + &mangled_container); + } + } else { + write!(&mut created_container, "pub type {} = ", mangled_container).unwrap(); + write!(&mut created_container, "{}::C{}Templ<", Self::container_templ_path(), container_type).unwrap(); + self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true); + writeln!(&mut created_container, ">;").unwrap(); - write!(&mut created_container, "#[no_mangle]\npub static {}_free: extern \"C\" fn({}) = ", mangled_container, mangled_container).unwrap(); - write!(&mut created_container, "{}::C{}Templ_free::<", Self::container_templ_path(), container_type).unwrap(); - self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true); - writeln!(&mut created_container, ">;").unwrap(); + write!(&mut created_container, "#[no_mangle]\npub static {}_free: extern \"C\" fn({}) = ", mangled_container, mangled_container).unwrap(); + write!(&mut created_container, "{}::C{}Templ_free::<", Self::container_templ_path(), container_type).unwrap(); + self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true); + writeln!(&mut created_container, ">;").unwrap(); - if !self.write_template_constructor(&mut created_container, container_type, &mangled_container, &args, generics, is_ref) { - return false; + if !self.write_template_constructor(&mut created_container, container_type, &mangled_container, &args, generics, is_ref) { + return false; + } } self.crate_types.templates_defined.insert(mangled_container.clone(), true); diff --git a/lightning-c-bindings/src/c_types/mod.rs b/lightning-c-bindings/src/c_types/mod.rs index 90f86f18f..5f8eb258a 100644 --- a/lightning-c-bindings/src/c_types/mod.rs +++ b/lightning-c-bindings/src/c_types/mod.rs @@ -259,14 +259,14 @@ impl Into<&'static str> for Str { // everywhere in the containers. #[repr(C)] -pub union CResultPtr { - pub result: *mut O, - pub err: *mut E, +pub(crate) union CResultPtr { + pub(crate) result: *mut O, + pub(crate) err: *mut E, } #[repr(C)] -pub struct CResultTempl { - pub contents: CResultPtr, - pub result_ok: bool, +pub(crate) struct CResultTempl { + pub(crate) contents: CResultPtr, + pub(crate) result_ok: bool, } impl CResultTempl { pub(crate) extern "C" fn ok(o: O) -> Self { @@ -286,7 +286,6 @@ impl CResultTempl { } } } -pub extern "C" fn CResultTempl_free(_res: CResultTempl) { } impl Drop for CResultTempl { fn drop(&mut self) { if self.result_ok { -- 2.39.5