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

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE>
   5 // or the MIT license <LICENSE-MIT>, at your option.
   6 // You may not use this file except in accordance with one or both of these
   7 // licenses.
   8
   9 //! Printing logic for basic blocks of Rust-mapped code - parts of functions and declarations but
  10 //! not the full mapping logic.
  11
  12 use std::fs::File;
  13 use std::io::Write;
  14 use proc_macro2::{TokenTree, Span};
  15
  16 use crate::types::*;
  17
  18 /// Writes out a C++ wrapper class for the given type, which contains various utilities to access
  19 /// the underlying C-mapped type safely avoiding some common memory management issues by handling
  20 /// resource-freeing and prevending accidental raw copies.
  21 pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool) {
  22         writeln!(cpp_header_file, "class {} {{", ty).unwrap();
  23         writeln!(cpp_header_file, "private:").unwrap();
  24         writeln!(cpp_header_file, "\tLDK{} self;", ty).unwrap();
  25         writeln!(cpp_header_file, "public:").unwrap();
  26         writeln!(cpp_header_file, "\t{}(const {}&) = delete;", ty, ty).unwrap();
  27         writeln!(cpp_header_file, "\t{}({}&& o) : self(o.self) {{ memset(&o, 0, sizeof({})); }}", ty, ty, ty).unwrap();
  28         writeln!(cpp_header_file, "\t{}(LDK{}&& m_self) : self(m_self) {{ memset(&m_self, 0, sizeof(LDK{})); }}", ty, ty, ty).unwrap();
  29         writeln!(cpp_header_file, "\toperator LDK{}() && {{ LDK{} res = self; memset(&self, 0, sizeof(LDK{})); return res; }}", ty, ty, ty).unwrap();
  30         if has_destructor {
  31                 writeln!(cpp_header_file, "\t~{}() {{ {}_free(self); }}", ty, ty).unwrap();
  32                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ {}_free(self); self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty, ty).unwrap();
  33         } else {
  34                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty).unwrap();
  35         }
  36         writeln!(cpp_header_file, "\tLDK{}* operator &() {{ return &self; }}", ty).unwrap();
  37         writeln!(cpp_header_file, "\tLDK{}* operator ->() {{ return &self; }}", ty).unwrap();
  38         writeln!(cpp_header_file, "\tconst LDK{}* operator &() const {{ return &self; }}", ty).unwrap();
  39         writeln!(cpp_header_file, "\tconst LDK{}* operator ->() const {{ return &self; }}", ty).unwrap();
  40         writeln!(cpp_header_file, "}};").unwrap();
  41 }
  42
  43 /// Writes out a C-callable concrete Result<A, B> struct and utility methods
  44 pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str, ok_type: &str, err_type: &str, clonable: bool) {
  45         writeln!(w, "#[repr(C)]").unwrap();
  46         writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap();
  47         if ok_type != "()" {
  48                 writeln!(w, "\tpub result: *mut {},", ok_type).unwrap();
  49         } else {
  50                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the OK variant").unwrap();
  51                 writeln!(w, "\tpub result: *mut std::ffi::c_void,").unwrap();
  52         }
  53         if err_type != "()" {
  54                 writeln!(w, "\tpub err: *mut {},", err_type).unwrap();
  55         } else {
  56                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the Err variant").unwrap();
  57                 writeln!(w, "\tpub err: *mut std::ffi::c_void,").unwrap();
  58         }
  59         writeln!(w, "}}").unwrap();
  60         writeln!(w, "#[repr(C)]").unwrap();
  61         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
  62         writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap();
  63         writeln!(w, "\tpub result_ok: bool,").unwrap();
  64         writeln!(w, "}}").unwrap();
  65
  66         writeln!(w, "#[no_mangle]").unwrap();
  67         if ok_type != "()" {
  68                 writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap();
  69         } else {
  70                 writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap();
  71         }
  72         writeln!(w, "\t{} {{", mangled_container).unwrap();
  73         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  74         if ok_type != "()" {
  75                 writeln!(w, "\t\t\tresult: Box::into_raw(Box::new(o)),").unwrap();
  76         } else {
  77                 writeln!(w, "\t\t\tresult: std::ptr::null_mut(),").unwrap();
  78         }
  79         writeln!(w, "\t\t}},").unwrap();
  80         writeln!(w, "\t\tresult_ok: true,").unwrap();
  81         writeln!(w, "\t}}").unwrap();
  82         writeln!(w, "}}").unwrap();
  83
  84         writeln!(w, "#[no_mangle]").unwrap();
  85         if err_type != "()" {
  86                 writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap();
  87         } else {
  88                 writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap();
  89         }
  90         writeln!(w, "\t{} {{", mangled_container).unwrap();
  91         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  92         if err_type != "()" {
  93                 writeln!(w, "\t\t\terr: Box::into_raw(Box::new(e)),").unwrap();
  94         } else {
  95                 writeln!(w, "\t\t\terr: std::ptr::null_mut(),").unwrap();
  96         }
  97         writeln!(w, "\t\t}},").unwrap();
  98         writeln!(w, "\t\tresult_ok: false,").unwrap();
  99         writeln!(w, "\t}}").unwrap();
 100         writeln!(w, "}}").unwrap();
 101
 102         writeln!(w, "#[no_mangle]").unwrap();
 103         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 104         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 105         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 106         writeln!(w, "\t\tif self.result_ok {{").unwrap();
 107         if ok_type != "()" {
 108                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap();
 109                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap();
 110                 writeln!(w, "\t\t\t}}").unwrap();
 111         }
 112         writeln!(w, "\t\t}} else {{").unwrap();
 113         if err_type != "()" {
 114                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap();
 115                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap();
 116                 writeln!(w, "\t\t\t}}").unwrap();
 117         }
 118         writeln!(w, "\t\t}}").unwrap();
 119         writeln!(w, "\t}}").unwrap();
 120         writeln!(w, "}}").unwrap();
 121
 122         // TODO: Templates should use () now that they can, too
 123         let templ_ok_type = if ok_type != "()" { ok_type } else { "u8" };
 124         let templ_err_type = if err_type != "()" { err_type } else { "u8" };
 125
 126         writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", templ_ok_type, templ_err_type, mangled_container).unwrap();
 127         writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", templ_ok_type, templ_err_type).unwrap();
 128         writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
 129         if ok_type != "()" {
 130                 writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
 131                 writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap();
 132                 writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap();
 133         } else {
 134                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap();
 135                 writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap();
 136                 writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap();
 137         }
 138         writeln!(w, "\t\t}} else {{").unwrap();
 139         if err_type != "()" {
 140                 writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap();
 141                 writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap();
 142                 writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap();
 143         } else {
 144                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap();
 145                 writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap();
 146                 writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap();
 147         }
 148         writeln!(w, "\t\t}};").unwrap();
 149         writeln!(w, "\t\tSelf {{").unwrap();
 150         writeln!(w, "\t\t\tcontents,").unwrap();
 151         writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap();
 152         writeln!(w, "\t\t}}").unwrap();
 153         writeln!(w, "\t}}").unwrap();
 154         writeln!(w, "}}").unwrap();
 155
 156         if clonable {
 157                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 158                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 159                 writeln!(w, "\t\tif self.result_ok {{").unwrap();
 160                 writeln!(w, "\t\t\tSelf {{ result_ok: true, contents: {}Ptr {{", mangled_container).unwrap();
 161                 if ok_type != "()" {
 162                         writeln!(w, "\t\t\t\tresult: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.result }})))", ok_type).unwrap();
 163                 } else {
 164                         writeln!(w, "\t\t\t\tresult: std::ptr::null_mut()").unwrap();
 165                 }
 166                 writeln!(w, "\t\t\t}} }}").unwrap();
 167                 writeln!(w, "\t\t}} else {{").unwrap();
 168                 writeln!(w, "\t\t\tSelf {{ result_ok: false, contents: {}Ptr {{", mangled_container).unwrap();
 169                 if err_type != "()" {
 170                         writeln!(w, "\t\t\t\terr: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.err }})))", err_type).unwrap();
 171                 } else {
 172                         writeln!(w, "\t\t\t\terr: std::ptr::null_mut()").unwrap();
 173                 }
 174                 writeln!(w, "\t\t\t}} }}").unwrap();
 175                 writeln!(w, "\t\t}}").unwrap();
 176                 writeln!(w, "\t}}").unwrap();
 177                 writeln!(w, "}}").unwrap();
 178                 writeln!(w, "#[no_mangle]").unwrap();
 179                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 180         }
 181 }
 182
 183 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 184 pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 185         writeln!(w, "#[repr(C)]").unwrap();
 186         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 187         writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
 188         writeln!(w, "\tpub datalen: usize").unwrap();
 189         writeln!(w, "}}").unwrap();
 190
 191         writeln!(w, "impl {} {{", mangled_container).unwrap();
 192         writeln!(w, "\t#[allow(unused)] pub(crate) fn into_rust(&mut self) -> Vec<{}> {{", inner_type).unwrap();
 193         writeln!(w, "\t\tif self.datalen == 0 {{ return Vec::new(); }}").unwrap();
 194         writeln!(w, "\t\tlet ret = unsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }}.into();").unwrap();
 195         writeln!(w, "\t\tself.data = std::ptr::null_mut();").unwrap();
 196         writeln!(w, "\t\tself.datalen = 0;").unwrap();
 197         writeln!(w, "\t\tret").unwrap();
 198         writeln!(w, "\t}}").unwrap();
 199         writeln!(w, "\t#[allow(unused)] pub(crate) fn as_slice(&self) -> &[{}] {{", inner_type).unwrap();
 200         writeln!(w, "\t\tunsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }}").unwrap();
 201         writeln!(w, "\t}}").unwrap();
 202         writeln!(w, "}}").unwrap();
 203
 204         writeln!(w, "impl From<Vec<{}>> for {} {{", inner_type, mangled_container).unwrap();
 205         writeln!(w, "\tfn from(v: Vec<{}>) -> Self {{", inner_type).unwrap();
 206         writeln!(w, "\t\tlet datalen = v.len();").unwrap();
 207         writeln!(w, "\t\tlet data = Box::into_raw(v.into_boxed_slice());").unwrap();
 208         writeln!(w, "\t\tSelf {{ datalen, data: unsafe {{ (*data).as_mut_ptr() }} }}").unwrap();
 209         writeln!(w, "\t}}").unwrap();
 210         writeln!(w, "}}").unwrap();
 211
 212         writeln!(w, "#[no_mangle]").unwrap();
 213         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 214         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 215         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 216         writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
 217         writeln!(w, "\t\tunsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
 218         writeln!(w, "\t}}").unwrap();
 219         writeln!(w, "}}").unwrap();
 220         if clonable {
 221                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 222                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 223                 writeln!(w, "\t\tlet mut res = Vec::new();").unwrap();
 224                 writeln!(w, "\t\tif self.datalen == 0 {{ return Self::from(res); }}").unwrap();
 225                 writeln!(w, "\t\tres.extend_from_slice(unsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }});").unwrap();
 226                 writeln!(w, "\t\tSelf::from(res)").unwrap();
 227                 writeln!(w, "\t}}").unwrap();
 228                 writeln!(w, "}}").unwrap();
 229         }
 230 }
 231
 232 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 233 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str, types: &[String], clonable: bool) {
 234         writeln!(w, "#[repr(C)]").unwrap();
 235         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 236         for (idx, ty) in types.iter().enumerate() {
 237                 writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
 238         }
 239         writeln!(w, "}}").unwrap();
 240
 241         let mut tuple_str = "(".to_owned();
 242         for (idx, ty) in types.iter().enumerate() {
 243                 if idx != 0 { tuple_str += ", "; }
 244                 tuple_str += ty;
 245         }
 246         tuple_str += ")";
 247
 248         writeln!(w, "impl From<{}> for {} {{", tuple_str, mangled_container).unwrap();
 249         writeln!(w, "\tfn from (tup: {}) -> Self {{", tuple_str).unwrap();
 250         writeln!(w, "\t\tSelf {{").unwrap();
 251         for idx in 0..types.len() {
 252                 writeln!(w, "\t\t\t{}: tup.{},", ('a' as u8 + idx as u8) as char, idx).unwrap();
 253         }
 254         writeln!(w, "\t\t}}").unwrap();
 255         writeln!(w, "\t}}").unwrap();
 256         writeln!(w, "}}").unwrap();
 257         writeln!(w, "impl {} {{", mangled_container).unwrap();
 258         writeln!(w, "\t#[allow(unused)] pub(crate) fn to_rust(mut self) -> {} {{", tuple_str).unwrap();
 259         write!(w, "\t\t(").unwrap();
 260         for idx in 0..types.len() {
 261                 write!(w, "{}self.{}", if idx != 0 {", "} else {""}, ('a' as u8 + idx as u8) as char).unwrap();
 262         }
 263         writeln!(w, ")").unwrap();
 264         writeln!(w, "\t}}").unwrap();
 265         writeln!(w, "}}").unwrap();
 266
 267         if clonable {
 268                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 269                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 270                 writeln!(w, "\t\tSelf {{").unwrap();
 271                 for idx in 0..types.len() {
 272                         writeln!(w, "\t\t\t{}: self.{}.clone(),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
 273                 }
 274                 writeln!(w, "\t\t}}").unwrap();
 275                 writeln!(w, "\t}}").unwrap();
 276                 writeln!(w, "}}").unwrap();
 277                 writeln!(w, "#[no_mangle]").unwrap();
 278                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 279         }
 280
 281         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
 282         for (idx, gen) in types.iter().enumerate() {
 283                 write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
 284                 //if !self.write_c_type_intern(&mut created_container, gen, generics, false, false, false) { return false; }
 285                 write!(w, "{}", gen).unwrap();
 286         }
 287         writeln!(w, ") -> {} {{", mangled_container).unwrap();
 288         write!(w, "\t{} {{ ", mangled_container).unwrap();
 289         for idx in 0..types.len() {
 290                 write!(w, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
 291         }
 292         writeln!(w, "}}\n}}\n").unwrap();
 293
 294         writeln!(w, "#[no_mangle]").unwrap();
 295         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 296 }
 297
 298 /// Prints the docs from a given attribute list unless its tagged no export
 299 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
 300         for attr in attrs.iter() {
 301                 let tokens_clone = attr.tokens.clone();
 302                 let mut token_iter = tokens_clone.into_iter();
 303                 if let Some(token) = token_iter.next() {
 304                         match token {
 305                                 TokenTree::Punct(c) if c.as_char() == '=' => {
 306                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
 307                                 },
 308                                 TokenTree::Group(_) => continue, // eg #[derive()]
 309                                 _ => unimplemented!(),
 310                         }
 311                 } else { continue; }
 312                 match attr.style {
 313                         syn::AttrStyle::Inner(_) => {
 314                                 match token_iter.next().unwrap() {
 315                                         TokenTree::Literal(lit) => {
 316                                                 // Drop the first and last chars from lit as they are always "
 317                                                 let doc = format!("{}", lit);
 318                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 319                                         },
 320                                         _ => unimplemented!(),
 321                                 }
 322                         },
 323                         syn::AttrStyle::Outer => {
 324                                 match token_iter.next().unwrap() {
 325                                         TokenTree::Literal(lit) => {
 326                                                 // Drop the first and last chars from lit as they are always "
 327                                                 let doc = format!("{}", lit);
 328                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 329                                         },
 330                                         _ => unimplemented!(),
 331                                 }
 332                         },
 333                 }
 334         }
 335 }
 336
 337 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
 338 /// including the closing parenthesis and return value, but not including the open bracket or any
 339 /// trailing semicolons.
 340 ///
 341 /// Usable both for a function definition and declaration.
 342 ///
 343 /// this_param is used when returning Self or accepting a self parameter, and should be the
 344 /// concrete, mapped type.
 345 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) {
 346         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
 347                         sig.abi.is_some() || sig.variadic.is_some() {
 348                 unimplemented!();
 349         }
 350         if sig.generics.lt_token.is_some() {
 351                 for generic in sig.generics.params.iter() {
 352                         match generic {
 353                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
 354                                         // We ignore these, if they're not on skipped args, we'll blow up
 355                                         // later, and lifetimes we just hope the C client enforces.
 356                                 },
 357                                 _ => unimplemented!(),
 358                         }
 359                 }
 360         }
 361
 362         let mut first_arg = true;
 363         let mut num_unused = 0;
 364         for inp in sig.inputs.iter() {
 365                 match inp {
 366                         syn::FnArg::Receiver(recv) => {
 367                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 368                                 write!(w, "this_arg: {}{}",
 369                                         match (self_ptr, recv.mutability.is_some()) {
 370                                                 (true, true) => "*mut ",
 371                                                 (true, false) => "*const ",
 372                                                 (false, true) => "&mut ",
 373                                                 (false, false) => "&",
 374                                         }, this_param).unwrap();
 375                                 assert!(first_arg);
 376                                 first_arg = false;
 377                         },
 378                         syn::FnArg::Typed(arg) => {
 379                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 380                                 if !arg.attrs.is_empty() { unimplemented!(); }
 381                                 // First get the c type so that we can check if it ends up being a reference:
 382                                 let mut c_type = Vec::new();
 383                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 384                                 match &*arg.pat {
 385                                         syn::Pat::Ident(ident) => {
 386                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 387                                                         unimplemented!();
 388                                                 }
 389                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 390                                                 first_arg = false;
 391                                         },
 392                                         syn::Pat::Wild(wild) => {
 393                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 394                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 395                                                 num_unused += 1;
 396                                         },
 397                                         _ => unimplemented!(),
 398                                 }
 399                                 w.write(&c_type).unwrap();
 400                         }
 401                 }
 402         }
 403         write!(w, ")").unwrap();
 404         match &sig.output {
 405                 syn::ReturnType::Type(_, rtype) => {
 406                         write!(w, " -> ").unwrap();
 407                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 408                                 if remaining_path.next().is_none() {
 409                                         write!(w, "{}", this_param).unwrap();
 410                                         return;
 411                                 }
 412                         }
 413                         if let syn::Type::Reference(r) = &**rtype {
 414                                 // We can't return a reference, cause we allocate things on the stack.
 415                                 types.write_c_type(w, &*r.elem, generics, true);
 416                         } else {
 417                                 types.write_c_type(w, &*rtype, generics, true);
 418                         }
 419                 },
 420                 _ => {},
 421         }
 422 }
 423
 424 /// Print the main part of a method declaration body, starting with a newline after the function
 425 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 426 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 427 /// parameters we mapped to/from C here.
 428 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) {
 429         let mut num_unused = 0;
 430         for inp in sig.inputs.iter() {
 431                 match inp {
 432                         syn::FnArg::Receiver(_) => {},
 433                         syn::FnArg::Typed(arg) => {
 434                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 435                                 if !arg.attrs.is_empty() { unimplemented!(); }
 436                                 macro_rules! write_new_var {
 437                                         ($ident: expr, $ty: expr) => {
 438                                                 if to_c {
 439                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 440                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 441                                                         }
 442                                                 } else {
 443                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 444                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 445                                                         }
 446                                                 }
 447                                         }
 448                                 }
 449                                 match &*arg.pat {
 450                                         syn::Pat::Ident(ident) => {
 451                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 452                                                         unimplemented!();
 453                                                 }
 454                                                 write_new_var!(ident.ident, *arg.ty);
 455                                         },
 456                                         syn::Pat::Wild(w) => {
 457                                                 if !w.attrs.is_empty() { unimplemented!(); }
 458                                                 write_new_var!(syn::Ident::new(&format!("unused_{}", num_unused), Span::call_site()), *arg.ty);
 459                                                 num_unused += 1;
 460                                         },
 461                                         _ => unimplemented!(),
 462                                 }
 463                         }
 464                 }
 465         }
 466         match &sig.output {
 467                 syn::ReturnType::Type(_, _) => {
 468                         write!(w, "let mut ret = ").unwrap();
 469                 },
 470                 _ => {},
 471         }
 472 }
 473
 474 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 475 /// final return statement returning the method's result. Should be followed by a single closing
 476 /// bracket.
 477 ///
 478 /// The return value is expected to be bound to a variable named `ret` which is available after a
 479 /// method-call-ending semicolon.
 480 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) {
 481         let mut first_arg = true;
 482         let mut num_unused = 0;
 483         for inp in sig.inputs.iter() {
 484                 match inp {
 485                         syn::FnArg::Receiver(recv) => {
 486                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 487                                 if to_c {
 488                                         write!(w, "self.this_arg").unwrap();
 489                                         first_arg = false;
 490                                 }
 491                         },
 492                         syn::FnArg::Typed(arg) => {
 493                                 if types.skip_arg(&*arg.ty, generics) {
 494                                         if !to_c {
 495                                                 if !first_arg {
 496                                                         write!(w, ", ").unwrap();
 497                                                 }
 498                                                 first_arg = false;
 499                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 500                                         }
 501                                         continue;
 502                                 }
 503                                 if !arg.attrs.is_empty() { unimplemented!(); }
 504                                 macro_rules! write_ident {
 505                                         ($ident: expr) => {
 506                                                 if !first_arg {
 507                                                         write!(w, ", ").unwrap();
 508                                                 }
 509                                                 first_arg = false;
 510                                                 if to_c {
 511                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 512                                                         write!(w, "{}", $ident).unwrap();
 513                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 514                                                 } else {
 515                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 516                                                         write!(w, "{}", $ident).unwrap();
 517                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 518                                                 }
 519                                         }
 520                                 }
 521                                 match &*arg.pat {
 522                                         syn::Pat::Ident(ident) => {
 523                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 524                                                         unimplemented!();
 525                                                 }
 526                                                 write_ident!(ident.ident);
 527                                         },
 528                                         syn::Pat::Wild(w) => {
 529                                                 if !w.attrs.is_empty() { unimplemented!(); }
 530                                                 write_ident!(format!("unused_{}", num_unused));
 531                                                 num_unused += 1;
 532                                         },
 533                                         _ => unimplemented!(),
 534                                 }
 535                         }
 536                 }
 537         }
 538         write!(w, ")").unwrap();
 539         match &sig.output {
 540                 syn::ReturnType::Type(_, rtype) => {
 541                         write!(w, ";\n\t{}", extra_indent).unwrap();
 542
 543                         let self_segs_iter = first_seg_self(&*rtype);
 544                         if to_c && first_seg_self(&*rtype).is_some() {
 545                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 546                                 write!(w, "ret").unwrap();
 547                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 548                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 549                                 write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
 550                         } else if to_c {
 551                                 let new_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), rtype, generics);
 552                                 if new_var {
 553                                         write!(w, "\n\t{}", extra_indent).unwrap();
 554                                 }
 555                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 556                                 write!(w, "ret").unwrap();
 557                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 558                         } else {
 559                                 let ret_returned = if let syn::Type::Reference(_) = &**rtype { true } else { false };
 560                                 let new_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), &rtype, generics, true);
 561                                 if new_var {
 562                                         write!(w, "\n\t{}", extra_indent).unwrap();
 563                                 }
 564                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 565                                 write!(w, "{}ret", if ret_returned && !new_var { "*" } else { "" }).unwrap();
 566                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 567                         }
 568                 }
 569                 _ => {},
 570         }
 571 }
 572
 573 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 574 /// greater-than symbols, if any generic parameters are defined.
 575 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 576         let mut gen_types = GenericTypes::new();
 577         assert!(gen_types.learn_generics(generics, types));
 578         if !generics.params.is_empty() {
 579                 write!(w, "<").unwrap();
 580                 for (idx, generic) in generics.params.iter().enumerate() {
 581                         match generic {
 582                                 syn::GenericParam::Type(type_param) => {
 583                                         let mut printed_param = false;
 584                                         for bound in type_param.bounds.iter() {
 585                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 586                                                         assert_simple_bound(&trait_bound);
 587                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
 588                                                         if printed_param {
 589                                                                 unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
 590                                                         }
 591                                                         printed_param = true;
 592                                                 }
 593                                         }
 594                                 },
 595                                 syn::GenericParam::Lifetime(lt) => {
 596                                         if concrete_lifetimes {
 597                                                 write!(w, "'static").unwrap();
 598                                         } else {
 599                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 600                                         }
 601                                 },
 602                                 _ => unimplemented!(),
 603                         }
 604                 }
 605                 write!(w, ">").unwrap();
 606         }
 607 }
 608
 609