_ Git - rust-lightning/blob - c-bindings-gen/src/blocks.rs

   1 //! Printing logic for basic blocks of Rust-mapped code - parts of functions and declarations but
   2 //! not the full mapping logic.
   3
   4 use std::fs::File;
   5 use std::io::Write;
   6 use proc_macro2::{TokenTree, Span};
   7
   8 use crate::GlobalOpts;
   9 use crate::types::*;
  10
  11 /// Writes out a C++ wrapper class for the given type, which contains various utilities to access
  12 /// the underlying C-mapped type safely avoiding some common memory management issues by handling
  13 /// resource-freeing and prevending accidental raw copies.
  14 pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool) {
  15         writeln!(cpp_header_file, "class {} {{", ty).unwrap();
  16         writeln!(cpp_header_file, "private:").unwrap();
  17         writeln!(cpp_header_file, "\tLDK{} self;", ty).unwrap();
  18         writeln!(cpp_header_file, "public:").unwrap();
  19         writeln!(cpp_header_file, "\t{}(const {}&) = delete;", ty, ty).unwrap();
  20         writeln!(cpp_header_file, "\t{}({}&& o) : self(o.self) {{ memset(&o, 0, sizeof({})); }}", ty, ty, ty).unwrap();
  21         writeln!(cpp_header_file, "\t{}(LDK{}&& m_self) : self(m_self) {{ memset(&m_self, 0, sizeof(LDK{})); }}", ty, ty, ty).unwrap();
  22         writeln!(cpp_header_file, "\toperator LDK{}() && {{ LDK{} res = self; memset(&self, 0, sizeof(LDK{})); return res; }}", ty, ty, ty).unwrap();
  23         if has_destructor {
  24                 writeln!(cpp_header_file, "\t~{}() {{ {}_free(self); }}", ty, ty).unwrap();
  25                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ {}_free(self); self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty, ty).unwrap();
  26         } else {
  27                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty).unwrap();
  28         }
  29         writeln!(cpp_header_file, "\tLDK{}* operator &() {{ return &self; }}", ty).unwrap();
  30         writeln!(cpp_header_file, "\tLDK{}* operator ->() {{ return &self; }}", ty).unwrap();
  31         writeln!(cpp_header_file, "\tconst LDK{}* operator &() const {{ return &self; }}", ty).unwrap();
  32         writeln!(cpp_header_file, "\tconst LDK{}* operator ->() const {{ return &self; }}", ty).unwrap();
  33         writeln!(cpp_header_file, "}};").unwrap();
  34 }
  35
  36 /// Writes out a C-callable concrete Result<A, B> struct and utility methods
  37 pub fn write_result_block<W: std::io::Write>(w: &mut W, opts: &GlobalOpts, mangled_container: &str, ok_type: &str, err_type: &str) {
  38         writeln!(w, "#[repr(C)]").unwrap();
  39         writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap();
  40         if ok_type != "()" {
  41                 writeln!(w, "\tpub result: *mut {},", ok_type).unwrap();
  42         } else {
  43                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the OK variant").unwrap();
  44                 writeln!(w, "\tpub result: *mut std::ffi::c_void,").unwrap();
  45         }
  46         if err_type != "()" {
  47                 writeln!(w, "\tpub err: *mut {},", err_type).unwrap();
  48         } else {
  49                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the Err variant").unwrap();
  50                 writeln!(w, "\tpub err: *mut std::ffi::c_void,").unwrap();
  51         }
  52         writeln!(w, "}}").unwrap();
  53         writeln!(w, "{}", opts.struct_attributes).unwrap();
  54         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
  55         writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap();
  56         writeln!(w, "\tpub result_ok: bool,").unwrap();
  57         writeln!(w, "}}").unwrap();
  58
  59         writeln!(w, "#[no_mangle]").unwrap();
  60         if ok_type != "()" {
  61                 writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap();
  62         } else {
  63                 writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap();
  64         }
  65         writeln!(w, "\t{} {{", mangled_container).unwrap();
  66         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  67         if ok_type != "()" {
  68                 writeln!(w, "\t\t\tresult: Box::into_raw(Box::new(o)),").unwrap();
  69         } else {
  70                 writeln!(w, "\t\t\tresult: std::ptr::null_mut(),").unwrap();
  71         }
  72         writeln!(w, "\t\t}},").unwrap();
  73         writeln!(w, "\t\tresult_ok: true,").unwrap();
  74         writeln!(w, "\t}}").unwrap();
  75         writeln!(w, "}}").unwrap();
  76
  77         writeln!(w, "#[no_mangle]").unwrap();
  78         if err_type != "()" {
  79                 writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap();
  80         } else {
  81                 writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap();
  82         }
  83         writeln!(w, "\t{} {{", mangled_container).unwrap();
  84         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  85         if err_type != "()" {
  86                 writeln!(w, "\t\t\terr: Box::into_raw(Box::new(e)),").unwrap();
  87         } else {
  88                 writeln!(w, "\t\t\terr: std::ptr::null_mut(),").unwrap();
  89         }
  90         writeln!(w, "\t\t}},").unwrap();
  91         writeln!(w, "\t\tresult_ok: false,").unwrap();
  92         writeln!(w, "\t}}").unwrap();
  93         writeln!(w, "}}").unwrap();
  94
  95         writeln!(w, "#[no_mangle]").unwrap();
  96         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
  97         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
  98         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
  99         writeln!(w, "\t\tif self.result_ok {{").unwrap();
 100         if ok_type != "()" {
 101                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap();
 102                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap();
 103                 writeln!(w, "\t\t\t}}").unwrap();
 104         }
 105         writeln!(w, "\t\t}} else {{").unwrap();
 106         if err_type != "()" {
 107                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap();
 108                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap();
 109                 writeln!(w, "\t\t\t}}").unwrap();
 110         }
 111         writeln!(w, "\t\t}}").unwrap();
 112         writeln!(w, "\t}}").unwrap();
 113         writeln!(w, "}}").unwrap();
 114
 115         // TODO: Templates should use () now that they can, too
 116         let templ_ok_type = if ok_type != "()" { ok_type } else { "u8" };
 117         let templ_err_type = if err_type != "()" { err_type } else { "u8" };
 118
 119         writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", templ_ok_type, templ_err_type, mangled_container).unwrap();
 120         writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", templ_ok_type, templ_err_type).unwrap();
 121         writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
 122         if ok_type != "()" {
 123                 writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
 124                 writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap();
 125                 writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap();
 126         } else {
 127                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap();
 128                 writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap();
 129                 writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap();
 130         }
 131         writeln!(w, "\t\t}} else {{").unwrap();
 132         if err_type != "()" {
 133                 writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap();
 134                 writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap();
 135                 writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap();
 136         } else {
 137                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap();
 138                 writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap();
 139                 writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap();
 140         }
 141         writeln!(w, "\t\t}};").unwrap();
 142         writeln!(w, "\t\tSelf {{").unwrap();
 143         writeln!(w, "\t\t\tcontents,").unwrap();
 144         writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap();
 145         writeln!(w, "\t\t}}").unwrap();
 146         writeln!(w, "\t}}").unwrap();
 147         writeln!(w, "}}").unwrap();
 148 }
 149
 150 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 151 pub fn write_vec_block<W: std::io::Write>(w: &mut W, opts: &GlobalOpts, mangled_container: &str, inner_type: &str) {
 152         writeln!(w, "{}", opts.struct_attributes).unwrap();
 153         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 154         writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
 155         writeln!(w, "\tpub datalen: usize").unwrap();
 156         writeln!(w, "}}").unwrap();
 157
 158         writeln!(w, "impl {} {{", mangled_container).unwrap();
 159         writeln!(w, "\t#[allow(unused)] pub(crate) fn into_rust(&mut self) -> Vec<{}> {{", inner_type).unwrap();
 160         writeln!(w, "\t\tif self.datalen == 0 {{ return Vec::new(); }}").unwrap();
 161         writeln!(w, "\t\tlet ret = unsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }}.into();").unwrap();
 162         writeln!(w, "\t\tself.data = std::ptr::null_mut();").unwrap();
 163         writeln!(w, "\t\tself.datalen = 0;").unwrap();
 164         writeln!(w, "\t\tret").unwrap();
 165         writeln!(w, "\t}}").unwrap();
 166         writeln!(w, "\t#[allow(unused)] pub(crate) fn as_slice(&self) -> &[{}] {{", inner_type).unwrap();
 167         writeln!(w, "\t\tunsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }}").unwrap();
 168         writeln!(w, "\t}}").unwrap();
 169         writeln!(w, "}}").unwrap();
 170
 171         writeln!(w, "impl From<Vec<{}>> for {} {{", inner_type, mangled_container).unwrap();
 172         writeln!(w, "\tfn from(v: Vec<{}>) -> Self {{", inner_type).unwrap();
 173         writeln!(w, "\t\tlet datalen = v.len();").unwrap();
 174         writeln!(w, "\t\tlet data = Box::into_raw(v.into_boxed_slice());").unwrap();
 175         writeln!(w, "\t\tSelf {{ datalen, data: unsafe {{ (*data).as_mut_ptr() }} }}").unwrap();
 176         writeln!(w, "\t}}").unwrap();
 177         writeln!(w, "}}").unwrap();
 178
 179         writeln!(w, "#[no_mangle]").unwrap();
 180         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 181         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 182         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 183         writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
 184         writeln!(w, "\t\tunsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
 185         writeln!(w, "\t}}").unwrap();
 186         writeln!(w, "}}").unwrap();
 187         if inner_type == "u8" || mangled_container == "CVec_SpendableOutputDescriptorZ" { // XXX
 188                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 189                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 190                 writeln!(w, "\t\tlet mut res = Vec::new();").unwrap();
 191                 writeln!(w, "\t\tif self.datalen == 0 {{ return Self::from(res); }}").unwrap();
 192                 writeln!(w, "\t\tres.extend_from_slice(unsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }});").unwrap();
 193                 writeln!(w, "\t\tSelf::from(res)").unwrap();
 194                 writeln!(w, "\t}}").unwrap();
 195                 writeln!(w, "}}").unwrap();
 196         }
 197 }
 198
 199 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 200 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, opts: &GlobalOpts, mangled_container: &str, types: &[String]) {
 201         writeln!(w, "{}", opts.struct_attributes).unwrap();
 202         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 203         for (idx, ty) in types.iter().enumerate() {
 204                 writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
 205         }
 206         writeln!(w, "}}").unwrap();
 207
 208         let mut needs_clone = true;
 209         let mut tuple_str = "(".to_owned();
 210         for (idx, ty) in types.iter().enumerate() {
 211                 if idx != 0 { tuple_str += ", "; }
 212                 tuple_str += ty;
 213                 if !ty.starts_with("u") ||
 214                         ty.len() > 3 || ty.len() < 2 ||
 215                         ty.as_bytes()[1] < '0' as u8 || ty.as_bytes()[1] > '9' as u8 ||
 216                         (ty.len() == 3 && (ty.as_bytes()[2] < '0' as u8 || ty.as_bytes()[2] > '9' as u8)) {
 217                                 // For non-uXX types, we don't implement clone
 218                                 needs_clone = false;
 219                 }
 220         }
 221         tuple_str += ")";
 222
 223         writeln!(w, "impl From<{}> for {} {{", tuple_str, mangled_container).unwrap();
 224         writeln!(w, "\tfn from (tup: {}) -> Self {{", tuple_str).unwrap();
 225         writeln!(w, "\t\tSelf {{").unwrap();
 226         for idx in 0..types.len() {
 227                 writeln!(w, "\t\t\t{}: tup.{},", ('a' as u8 + idx as u8) as char, idx).unwrap();
 228         }
 229         writeln!(w, "\t\t}}").unwrap();
 230         writeln!(w, "\t}}").unwrap();
 231         writeln!(w, "}}").unwrap();
 232         writeln!(w, "impl {} {{", mangled_container).unwrap();
 233         writeln!(w, "\t#[allow(unused)] pub(crate) fn to_rust(mut self) -> {} {{", tuple_str).unwrap();
 234         write!(w, "\t\t(").unwrap();
 235         for idx in 0..types.len() {
 236                 write!(w, "{}self.{}", if idx != 0 {", "} else {""}, ('a' as u8 + idx as u8) as char).unwrap();
 237         }
 238         writeln!(w, ")").unwrap();
 239         writeln!(w, "\t}}").unwrap();
 240         writeln!(w, "}}").unwrap();
 241
 242         if needs_clone {
 243                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 244                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 245                 writeln!(w, "\t\tSelf {{").unwrap();
 246                 for idx in 0..types.len() {
 247                         writeln!(w, "\t\t\t{}: self.{}.clone(),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
 248                 }
 249                 writeln!(w, "\t\t}}").unwrap();
 250                 writeln!(w, "\t}}").unwrap();
 251                 writeln!(w, "}}").unwrap();
 252         }
 253
 254         writeln!(w, "#[no_mangle]").unwrap();
 255         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 256 }
 257
 258 /// Prints the docs from a given attribute list unless its tagged no export
 259 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
 260         for attr in attrs.iter() {
 261                 let tokens_clone = attr.tokens.clone();
 262                 let mut token_iter = tokens_clone.into_iter();
 263                 if let Some(token) = token_iter.next() {
 264                         match token {
 265                                 TokenTree::Punct(c) if c.as_char() == '=' => {
 266                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
 267                                 },
 268                                 TokenTree::Group(_) => continue, // eg #[derive()]
 269                                 _ => unimplemented!(),
 270                         }
 271                 } else { continue; }
 272                 match attr.style {
 273                         syn::AttrStyle::Inner(_) => {
 274                                 match token_iter.next().unwrap() {
 275                                         TokenTree::Literal(lit) => {
 276                                                 // Drop the first and last chars from lit as they are always "
 277                                                 let doc = format!("{}", lit);
 278                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 279                                         },
 280                                         _ => unimplemented!(),
 281                                 }
 282                         },
 283                         syn::AttrStyle::Outer => {
 284                                 match token_iter.next().unwrap() {
 285                                         TokenTree::Literal(lit) => {
 286                                                 // Drop the first and last chars from lit as they are always "
 287                                                 let doc = format!("{}", lit);
 288                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 289                                         },
 290                                         _ => unimplemented!(),
 291                                 }
 292                         },
 293                 }
 294         }
 295 }
 296
 297 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
 298 /// including the closing parenthesis and return value, but not including the open bracket or any
 299 /// trailing semicolons.
 300 ///
 301 /// Usable both for a function definition and declaration.
 302 ///
 303 /// this_param is used when returning Self or accepting a self parameter, and should be the
 304 /// concrete, mapped type.
 305 pub fn write_method_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, this_param: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, self_ptr: bool, fn_decl: bool) {
 306         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
 307                         sig.abi.is_some() || sig.variadic.is_some() {
 308                 unimplemented!();
 309         }
 310         if sig.generics.lt_token.is_some() {
 311                 for generic in sig.generics.params.iter() {
 312                         match generic {
 313                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
 314                                         // We ignore these, if they're not on skipped args, we'll blow up
 315                                         // later, and lifetimes we just hope the C client enforces.
 316                                 },
 317                                 _ => unimplemented!(),
 318                         }
 319                 }
 320         }
 321
 322         let mut first_arg = true;
 323         let mut num_unused = 0;
 324         for inp in sig.inputs.iter() {
 325                 match inp {
 326                         syn::FnArg::Receiver(recv) => {
 327                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 328                                 write!(w, "this_arg: {}{}",
 329                                         match (self_ptr, recv.mutability.is_some()) {
 330                                                 (true, true) => "*mut ",
 331                                                 (true, false) => "*const ",
 332                                                 (false, true) => "&mut ",
 333                                                 (false, false) => "&",
 334                                         }, this_param).unwrap();
 335                                 assert!(first_arg);
 336                                 first_arg = false;
 337                         },
 338                         syn::FnArg::Typed(arg) => {
 339                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 340                                 if !arg.attrs.is_empty() { unimplemented!(); }
 341                                 // First get the c type so that we can check if it ends up being a reference:
 342                                 let mut c_type = Vec::new();
 343                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 344                                 match &*arg.pat {
 345                                         syn::Pat::Ident(ident) => {
 346                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 347                                                         unimplemented!();
 348                                                 }
 349                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 350                                                 first_arg = false;
 351                                         },
 352                                         syn::Pat::Wild(wild) => {
 353                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 354                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 355                                                 num_unused += 1;
 356                                         },
 357                                         _ => unimplemented!(),
 358                                 }
 359                                 w.write(&c_type).unwrap();
 360                         }
 361                 }
 362         }
 363         write!(w, ")").unwrap();
 364         match &sig.output {
 365                 syn::ReturnType::Type(_, rtype) => {
 366                         write!(w, " -> ").unwrap();
 367                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 368                                 if remaining_path.next().is_none() {
 369                                         write!(w, "{}", this_param).unwrap();
 370                                         return;
 371                                 }
 372                         }
 373                         if let syn::Type::Reference(r) = &**rtype {
 374                                 // We can't return a reference, cause we allocate things on the stack.
 375                                 types.write_c_type(w, &*r.elem, generics, true);
 376                         } else {
 377                                 types.write_c_type(w, &*rtype, generics, true);
 378                         }
 379                 },
 380                 _ => {},
 381         }
 382 }
 383
 384 /// Print the main part of a method declaration body, starting with a newline after the function
 385 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 386 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 387 /// parameters we mapped to/from C here.
 388 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) {
 389         let mut num_unused = 0;
 390         for inp in sig.inputs.iter() {
 391                 match inp {
 392                         syn::FnArg::Receiver(_) => {},
 393                         syn::FnArg::Typed(arg) => {
 394                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 395                                 if !arg.attrs.is_empty() { unimplemented!(); }
 396                                 macro_rules! write_new_var {
 397                                         ($ident: expr, $ty: expr) => {
 398                                                 if to_c {
 399                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 400                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 401                                                         }
 402                                                 } else {
 403                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 404                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 405                                                         }
 406                                                 }
 407                                         }
 408                                 }
 409                                 match &*arg.pat {
 410                                         syn::Pat::Ident(ident) => {
 411                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 412                                                         unimplemented!();
 413                                                 }
 414                                                 write_new_var!(ident.ident, *arg.ty);
 415                                         },
 416                                         syn::Pat::Wild(w) => {
 417                                                 if !w.attrs.is_empty() { unimplemented!(); }
 418                                                 write_new_var!(syn::Ident::new(&format!("unused_{}", num_unused), Span::call_site()), *arg.ty);
 419                                                 num_unused += 1;
 420                                         },
 421                                         _ => unimplemented!(),
 422                                 }
 423                         }
 424                 }
 425         }
 426         match &sig.output {
 427                 syn::ReturnType::Type(_, _) => {
 428                         write!(w, "let mut ret = ").unwrap();
 429                 },
 430                 _ => {},
 431         }
 432 }
 433
 434 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 435 /// final return statement returning the method's result. Should be followed by a single closing
 436 /// bracket.
 437 ///
 438 /// The return value is expected to be bound to a variable named `ret` which is available after a
 439 /// method-call-ending semicolon.
 440 pub fn write_method_call_params<W: std::io::Write>(w: &mut W, sig: &syn::Signature, extra_indent: &str, types: &TypeResolver, generics: Option<&GenericTypes>, this_type: &str, to_c: bool) {
 441         let mut first_arg = true;
 442         let mut num_unused = 0;
 443         for inp in sig.inputs.iter() {
 444                 match inp {
 445                         syn::FnArg::Receiver(recv) => {
 446                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 447                                 if to_c {
 448                                         write!(w, "self.this_arg").unwrap();
 449                                         first_arg = false;
 450                                 }
 451                         },
 452                         syn::FnArg::Typed(arg) => {
 453                                 if types.skip_arg(&*arg.ty, generics) {
 454                                         if !to_c {
 455                                                 if !first_arg {
 456                                                         write!(w, ", ").unwrap();
 457                                                 }
 458                                                 first_arg = false;
 459                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 460                                         }
 461                                         continue;
 462                                 }
 463                                 if !arg.attrs.is_empty() { unimplemented!(); }
 464                                 macro_rules! write_ident {
 465                                         ($ident: expr) => {
 466                                                 if !first_arg {
 467                                                         write!(w, ", ").unwrap();
 468                                                 }
 469                                                 first_arg = false;
 470                                                 if to_c {
 471                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 472                                                         write!(w, "{}", $ident).unwrap();
 473                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 474                                                 } else {
 475                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 476                                                         write!(w, "{}", $ident).unwrap();
 477                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 478                                                 }
 479                                         }
 480                                 }
 481                                 match &*arg.pat {
 482                                         syn::Pat::Ident(ident) => {
 483                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 484                                                         unimplemented!();
 485                                                 }
 486                                                 write_ident!(ident.ident);
 487                                         },
 488                                         syn::Pat::Wild(w) => {
 489                                                 if !w.attrs.is_empty() { unimplemented!(); }
 490                                                 write_ident!(format!("unused_{}", num_unused));
 491                                                 num_unused += 1;
 492                                         },
 493                                         _ => unimplemented!(),
 494                                 }
 495                         }
 496                 }
 497         }
 498         write!(w, ")").unwrap();
 499         match &sig.output {
 500                 syn::ReturnType::Type(_, rtype) => {
 501                         write!(w, ";\n\t{}", extra_indent).unwrap();
 502
 503                         let self_segs_iter = first_seg_self(&*rtype);
 504                         if to_c && first_seg_self(&*rtype).is_some() {
 505                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 506                                 write!(w, "ret").unwrap();
 507                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 508                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 509                                 write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
 510                         } else if to_c {
 511                                 let new_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), rtype, generics);
 512                                 if new_var {
 513                                         write!(w, "\n\t{}", extra_indent).unwrap();
 514                                 }
 515                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 516                                 write!(w, "ret").unwrap();
 517                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 518                         } else {
 519                                 let ret_returned = if let syn::Type::Reference(_) = &**rtype { true } else { false };
 520                                 let new_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), &rtype, generics, true);
 521                                 if new_var {
 522                                         write!(w, "\n\t{}", extra_indent).unwrap();
 523                                 }
 524                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 525                                 write!(w, "{}ret", if ret_returned && !new_var { "*" } else { "" }).unwrap();
 526                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 527                         }
 528                 }
 529                 _ => {},
 530         }
 531 }
 532
 533 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 534 /// greater-than symbols, if any generic parameters are defined.
 535 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 536         let mut gen_types = GenericTypes::new();
 537         assert!(gen_types.learn_generics(generics, types));
 538         if !generics.params.is_empty() {
 539                 write!(w, "<").unwrap();
 540                 for (idx, generic) in generics.params.iter().enumerate() {
 541                         match generic {
 542                                 syn::GenericParam::Type(type_param) => {
 543                                         let mut printed_param = false;
 544                                         for bound in type_param.bounds.iter() {
 545                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 546                                                         assert_simple_bound(&trait_bound);
 547                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
 548                                                         if printed_param {
 549                                                                 unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
 550                                                         }
 551                                                         printed_param = true;
 552                                                 }
 553                                         }
 554                                 },
 555                                 syn::GenericParam::Lifetime(lt) => {
 556                                         if concrete_lifetimes {
 557                                                 write!(w, "'static").unwrap();
 558                                         } else {
 559                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 560                                         }
 561                                 },
 562                                 _ => unimplemented!(),
 563                         }
 564                 }
 565                 write!(w, ">").unwrap();
 566         }
 567 }
 568
 569