From c0c17650327b5aedba389bd7428358e29670506e Mon Sep 17 00:00:00 2001 From: Matt Corallo Date: Sun, 11 Apr 2021 22:14:26 -0400 Subject: [PATCH] Handle traits which require Clone when their supertraits do not We do this by adding a SuperTrait_clone method field in the Trait's object, which we call when cloning the Trait. --- c-bindings-gen/src/main.rs | 282 ++++++++++++++++++++++--------------- 1 file changed, 166 insertions(+), 116 deletions(-) diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs index 1d37bb2..06050c5 100644 --- a/c-bindings-gen/src/main.rs +++ b/c-bindings-gen/src/main.rs @@ -289,7 +289,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty writeln!(w, "\t/// An opaque pointer which is passed to your function implementations as an argument.").unwrap(); writeln!(w, "\t/// This has no meaning in the LDK, and can be NULL or any other value.").unwrap(); writeln!(w, "\tpub this_arg: *mut c_void,").unwrap(); - let mut generated_fields = Vec::new(); // Every field's name except this_arg, used in Clone generation + let mut generated_fields = Vec::new(); // Every field's (name, is_clonable) except this_arg, used in Clone generation for item in t.items.iter() { match item { &syn::TraitItem::Method(ref m) => { @@ -322,14 +322,14 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty // happen) as well as provide an Option<>al function pointer which is // called when the trait method is called which allows updating on the fly. write!(w, "\tpub {}: ", m.sig.ident).unwrap(); - generated_fields.push(format!("{}", m.sig.ident)); + generated_fields.push((format!("{}", m.sig.ident), true)); types.write_c_type(w, &*r.elem, Some(&gen_types), false); writeln!(w, ",").unwrap(); writeln!(w, "\t/// Fill in the {} field as a reference to it will be given to Rust after this returns", m.sig.ident).unwrap(); writeln!(w, "\t/// Note that this takes a pointer to this object, not the this_ptr like other methods do").unwrap(); writeln!(w, "\t/// This function pointer may be NULL if {} is filled in when this object is created and never needs updating.", m.sig.ident).unwrap(); writeln!(w, "\tpub set_{}: Option,", m.sig.ident, trait_name).unwrap(); - generated_fields.push(format!("set_{}", m.sig.ident)); + generated_fields.push((format!("set_{}", m.sig.ident), true)); // Note that cbindgen will now generate // typedef struct Thing {..., set_thing: (const Thing*), ...} Thing; // which does not compile since Thing is not defined before it is used. @@ -344,7 +344,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty } write!(w, "\tpub {}: extern \"C\" fn (", m.sig.ident).unwrap(); - generated_fields.push(format!("{}", m.sig.ident)); + generated_fields.push((format!("{}", m.sig.ident), true)); write_method_params(w, &m.sig, "c_void", types, Some(&gen_types), true, false); writeln!(w, ",").unwrap(); @@ -355,25 +355,30 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty } } // Add functions which may be required for supertrait implementations. + let mut requires_clone = false; + walk_supertraits!(t, Some(&types), ( + ("Clone", _) => requires_clone = true, + (_, _) => {} + ) ); walk_supertraits!(t, Some(&types), ( ("Clone", _) => { writeln!(w, "\t/// Creates a copy of the object pointed to by this_arg, for a copy of this {}.", trait_name).unwrap(); writeln!(w, "\t/// Note that the ultimate copy of the {} will have all function pointers the same as the original.", trait_name).unwrap(); writeln!(w, "\t/// May be NULL if no action needs to be taken, the this_arg pointer will be copied into the new {}.", trait_name).unwrap(); writeln!(w, "\tpub clone: Option *mut c_void>,").unwrap(); - generated_fields.push("clone".to_owned()); + generated_fields.push(("clone".to_owned(), true)); }, ("std::cmp::Eq", _) => { writeln!(w, "\t/// Checks if two objects are equal given this object's this_arg pointer and another object.").unwrap(); writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap(); writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap(); - generated_fields.push("eq".to_owned()); + generated_fields.push(("eq".to_owned(), true)); }, ("std::hash::Hash", _) => { writeln!(w, "\t/// Calculate a succinct non-cryptographic hash for an object given its this_arg pointer.").unwrap(); writeln!(w, "\t/// This is used, for example, for inclusion of this object in a hash map.").unwrap(); writeln!(w, "\tpub hash: extern \"C\" fn (this_arg: *const c_void) -> u64,").unwrap(); - generated_fields.push("hash".to_owned()); + generated_fields.push(("hash".to_owned(), true)); }, ("Send", _) => {}, ("Sync", _) => {}, (s, i) => { @@ -381,20 +386,127 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty let (docs, name, ret) = convert_trait_impl_field(s); writeln!(w, "\t/// {}", docs).unwrap(); writeln!(w, "\tpub {}: extern \"C\" fn (this_arg: *const c_void) -> {},", name, ret).unwrap(); - name + (name, true) // Assume clonable } else { // For in-crate supertraits, just store a C-mapped copy of the supertrait as a member. - writeln!(w, "/// Implementation of {} for this object.", i).unwrap(); + writeln!(w, "\t/// Implementation of {} for this object.", i).unwrap(); writeln!(w, "\tpub {}: crate::{},", i, s).unwrap(); - format!("{}", i) + let is_clonable = types.is_clonable(s); + if !is_clonable && requires_clone { + writeln!(w, "\t/// Creates a copy of the {}, for a copy of this {}.", i, trait_name).unwrap(); + writeln!(w, "\t/// Because {} doesn't natively support copying itself, you have to provide a full copy implementation here.", i).unwrap(); + writeln!(w, "\tpub {}_clone: extern \"C\" fn (orig_{}: &{}) -> {},", i, i, i, i).unwrap(); + } + (format!("{}", i), is_clonable) }); } ) ); writeln!(w, "\t/// Frees any resources associated with this object given its this_arg pointer.").unwrap(); writeln!(w, "\t/// Does not need to free the outer struct containing function pointers and may be NULL is no resources need to be freed.").unwrap(); writeln!(w, "\tpub free: Option,").unwrap(); - generated_fields.push("free".to_owned()); + generated_fields.push(("free".to_owned(), true)); writeln!(w, "}}").unwrap(); + + macro_rules! impl_trait_for_c { + ($t: expr, $impl_accessor: expr) => { + for item in $t.items.iter() { + match item { + syn::TraitItem::Method(m) => { + if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; } + if m.default.is_some() { unimplemented!(); } + if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() || + m.sig.abi.is_some() || m.sig.variadic.is_some() { + unimplemented!(); + } + gen_types.push_ctx(); + assert!(gen_types.learn_generics(&m.sig.generics, types)); + write!(w, "\tfn {}", m.sig.ident).unwrap(); + types.write_rust_generic_param(w, Some(&gen_types), m.sig.generics.params.iter()); + write!(w, "(").unwrap(); + for inp in m.sig.inputs.iter() { + match inp { + syn::FnArg::Receiver(recv) => { + if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); } + write!(w, "&").unwrap(); + if let Some(lft) = &recv.reference.as_ref().unwrap().1 { + write!(w, "'{} ", lft.ident).unwrap(); + } + if recv.mutability.is_some() { + write!(w, "mut self").unwrap(); + } else { + write!(w, "self").unwrap(); + } + }, + syn::FnArg::Typed(arg) => { + if !arg.attrs.is_empty() { unimplemented!(); } + match &*arg.pat { + syn::Pat::Ident(ident) => { + if !ident.attrs.is_empty() || ident.by_ref.is_some() || + ident.mutability.is_some() || ident.subpat.is_some() { + unimplemented!(); + } + write!(w, ", {}{}: ", if types.skip_arg(&*arg.ty, Some(&gen_types)) { "_" } else { "" }, ident.ident).unwrap(); + } + _ => unimplemented!(), + } + types.write_rust_type(w, Some(&gen_types), &*arg.ty); + } + } + } + write!(w, ")").unwrap(); + match &m.sig.output { + syn::ReturnType::Type(_, rtype) => { + write!(w, " -> ").unwrap(); + types.write_rust_type(w, Some(&gen_types), &*rtype) + }, + _ => {}, + } + write!(w, " {{\n\t\t").unwrap(); + match export_status(&m.attrs) { + ExportStatus::NoExport => { + unimplemented!(); + }, + _ => {}, + } + if let syn::ReturnType::Type(_, rtype) = &m.sig.output { + if let syn::Type::Reference(r) = &**rtype { + assert_eq!(m.sig.inputs.len(), 1); // Must only take self! + writeln!(w, "if let Some(f) = self{}.set_{} {{", $impl_accessor, m.sig.ident).unwrap(); + writeln!(w, "\t\t\t(f)(&self{});", $impl_accessor).unwrap(); + write!(w, "\t\t}}\n\t\t").unwrap(); + types.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&gen_types)); + write!(w, "self{}.{}", $impl_accessor, m.sig.ident).unwrap(); + types.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&gen_types)); + writeln!(w, "\n\t}}").unwrap(); + gen_types.pop_ctx(); + continue; + } + } + write_method_var_decl_body(w, &m.sig, "\t", types, Some(&gen_types), true); + write!(w, "(self{}.{})(", $impl_accessor, m.sig.ident).unwrap(); + write_method_call_params(w, &m.sig, "\t", types, Some(&gen_types), "", true); + + writeln!(w, "\n\t}}").unwrap(); + gen_types.pop_ctx(); + }, + &syn::TraitItem::Type(ref t) => { + if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); } + let mut bounds_iter = t.bounds.iter(); + match bounds_iter.next().unwrap() { + syn::TypeParamBound::Trait(tr) => { + writeln!(w, "\ttype {} = crate::{};", t.ident, types.resolve_path(&tr.path, Some(&gen_types))).unwrap(); + }, + _ => unimplemented!(), + } + if bounds_iter.next().is_some() { unimplemented!(); } + }, + _ => unimplemented!(), + } + } + } + } + + // Implement supertraits for the C-mapped struct. walk_supertraits!(t, Some(&types), ( ("Send", _) => writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap(), @@ -414,8 +526,13 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap(); writeln!(w, "\t{} {{", trait_name).unwrap(); writeln!(w, "\t\tthis_arg: if let Some(f) = orig.clone {{ (f)(orig.this_arg) }} else {{ orig.this_arg }},").unwrap(); - for field in generated_fields.iter() { - writeln!(w, "\t\t{}: orig.{}.clone(),", field, field).unwrap(); + for (field, clonable) in generated_fields.iter() { + if *clonable { + writeln!(w, "\t\t{}: Clone::clone(&orig.{}),", field, field).unwrap(); + } else { + writeln!(w, "\t\t{}: (orig.{}_clone)(&orig.{}),", field, field, field).unwrap(); + writeln!(w, "\t\t{}_clone: orig.{}_clone,", field, field).unwrap(); + } } writeln!(w, "\t}}\n}}").unwrap(); writeln!(w, "impl Clone for {} {{", trait_name).unwrap(); @@ -424,7 +541,18 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty writeln!(w, "\t}}\n}}").unwrap(); }, (s, i) => { - do_write_impl_trait(w, s, i, &trait_name); + if let Some(supertrait) = types.crate_types.traits.get(s) { + writeln!(w, "impl lightning::{} for {} {{", s, trait_name).unwrap(); // TODO: Drop hard-coded crate name here + impl_trait_for_c!(supertrait, format!(".{}", i)); + writeln!(w, "}}").unwrap(); + walk_supertraits!(supertrait, Some(&types), ( + ("Send", _) => writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap(), + ("Sync", _) => writeln!(w, "unsafe impl Sync for {} {{}}", trait_name).unwrap(), + _ => unimplemented!() + ) ); + } else { + do_write_impl_trait(w, s, i, &trait_name); + } } ) ); @@ -433,100 +561,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty write!(w, "impl rust{}", t.ident).unwrap(); maybe_write_generics(w, &t.generics, types, false); writeln!(w, " for {} {{", trait_name).unwrap(); - for item in t.items.iter() { - match item { - syn::TraitItem::Method(m) => { - if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; } - if m.default.is_some() { unimplemented!(); } - if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() || - m.sig.abi.is_some() || m.sig.variadic.is_some() { - unimplemented!(); - } - gen_types.push_ctx(); - assert!(gen_types.learn_generics(&m.sig.generics, types)); - write!(w, "\tfn {}", m.sig.ident).unwrap(); - types.write_rust_generic_param(w, Some(&gen_types), m.sig.generics.params.iter()); - write!(w, "(").unwrap(); - for inp in m.sig.inputs.iter() { - match inp { - syn::FnArg::Receiver(recv) => { - if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); } - write!(w, "&").unwrap(); - if let Some(lft) = &recv.reference.as_ref().unwrap().1 { - write!(w, "'{} ", lft.ident).unwrap(); - } - if recv.mutability.is_some() { - write!(w, "mut self").unwrap(); - } else { - write!(w, "self").unwrap(); - } - }, - syn::FnArg::Typed(arg) => { - if !arg.attrs.is_empty() { unimplemented!(); } - match &*arg.pat { - syn::Pat::Ident(ident) => { - if !ident.attrs.is_empty() || ident.by_ref.is_some() || - ident.mutability.is_some() || ident.subpat.is_some() { - unimplemented!(); - } - write!(w, ", {}{}: ", if types.skip_arg(&*arg.ty, Some(&gen_types)) { "_" } else { "" }, ident.ident).unwrap(); - } - _ => unimplemented!(), - } - types.write_rust_type(w, Some(&gen_types), &*arg.ty); - } - } - } - write!(w, ")").unwrap(); - match &m.sig.output { - syn::ReturnType::Type(_, rtype) => { - write!(w, " -> ").unwrap(); - types.write_rust_type(w, Some(&gen_types), &*rtype) - }, - _ => {}, - } - write!(w, " {{\n\t\t").unwrap(); - match export_status(&m.attrs) { - ExportStatus::NoExport => { - unimplemented!(); - }, - _ => {}, - } - if let syn::ReturnType::Type(_, rtype) = &m.sig.output { - if let syn::Type::Reference(r) = &**rtype { - assert_eq!(m.sig.inputs.len(), 1); // Must only take self! - writeln!(w, "if let Some(f) = self.set_{} {{", m.sig.ident).unwrap(); - writeln!(w, "\t\t\t(f)(self);").unwrap(); - write!(w, "\t\t}}\n\t\t").unwrap(); - types.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&gen_types)); - write!(w, "self.{}", m.sig.ident).unwrap(); - types.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&gen_types)); - writeln!(w, "\n\t}}").unwrap(); - gen_types.pop_ctx(); - continue; - } - } - write_method_var_decl_body(w, &m.sig, "\t", types, Some(&gen_types), true); - write!(w, "(self.{})(", m.sig.ident).unwrap(); - write_method_call_params(w, &m.sig, "\t", types, Some(&gen_types), "", true); - - writeln!(w, "\n\t}}").unwrap(); - gen_types.pop_ctx(); - }, - &syn::TraitItem::Type(ref t) => { - if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); } - let mut bounds_iter = t.bounds.iter(); - match bounds_iter.next().unwrap() { - syn::TypeParamBound::Trait(tr) => { - writeln!(w, "\ttype {} = crate::{};", t.ident, types.resolve_path(&tr.path, Some(&gen_types))).unwrap(); - }, - _ => unimplemented!(), - } - if bounds_iter.next().is_some() { unimplemented!(); } - }, - _ => unimplemented!(), - } - } + impl_trait_for_c!(t, ""); writeln!(w, "}}\n").unwrap(); writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap(); writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap(); @@ -819,6 +854,11 @@ fn writeln_impl(w: &mut W, i: &syn::ItemImpl, types: &mut Typ _ => {}, } } + let mut requires_clone = false; + walk_supertraits!(trait_obj, Some(&types), ( + ("Clone", _) => requires_clone = true, + (_, _) => {} + ) ); walk_supertraits!(trait_obj, Some(&types), ( ("Clone", _) => { writeln!(w, "\t\tclone: Some({}_clone_void),", ident).unwrap(); @@ -839,6 +879,9 @@ fn writeln_impl(w: &mut W, i: &syn::ItemImpl, types: &mut Typ } } write!(w, "\t\t}},\n").unwrap(); + if !types.is_clonable(s) && requires_clone { + writeln!(w, "\t\t{}_clone: {}_{}_clone,", t, ident, t).unwrap(); + } } else { write_trait_impl_field_assign(w, s, ident); } @@ -924,15 +967,22 @@ fn writeln_impl(w: &mut W, i: &syn::ItemImpl, types: &mut Typ } } walk_supertraits!(trait_obj, Some(&types), ( - (s, _) => { - if let Some(supertrait_obj) = types.crate_types.traits.get(s).cloned() { - for item in supertrait_obj.items.iter() { - match item { - syn::TraitItem::Method(m) => { - impl_meth!(m, s, supertrait_obj, "\t"); - }, - _ => {}, + (s, t) => { + if let Some(supertrait_obj) = types.crate_types.traits.get(s) { + if !types.is_clonable(s) && requires_clone { + writeln!(w, "extern \"C\" fn {}_{}_clone(orig: &crate::{}) -> crate::{} {{", ident, t, s, s).unwrap(); + writeln!(w, "\tcrate::{} {{", s).unwrap(); + writeln!(w, "\t\tthis_arg: orig.this_arg,").unwrap(); + writeln!(w, "\t\tfree: None,").unwrap(); + for item in supertrait_obj.items.iter() { + match item { + syn::TraitItem::Method(m) => { + write_meth!(m, supertrait_obj, ""); + }, + _ => {}, + } } + write!(w, "\t}}\n}}\n").unwrap(); } } } -- 2.30.2