_ 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::types::*;
   9
  10 /// Writes out a C++ wrapper class for the given type, which contains various utilities to access
  11 /// the underlying C-mapped type safely avoiding some common memory management issues by handling
  12 /// resource-freeing and prevending accidental raw copies.
  13 pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool) {
  14         writeln!(cpp_header_file, "class {} {{", ty).unwrap();
  15         writeln!(cpp_header_file, "private:").unwrap();
  16         writeln!(cpp_header_file, "\tLDK{} self;", ty).unwrap();
  17         writeln!(cpp_header_file, "public:").unwrap();
  18         writeln!(cpp_header_file, "\t{}(const {}&) = delete;", ty, ty).unwrap();
  19         writeln!(cpp_header_file, "\t{}({}&& o) : self(o.self) {{ memset(&o, 0, sizeof({})); }}", ty, ty, ty).unwrap();
  20         writeln!(cpp_header_file, "\t{}(LDK{}&& m_self) : self(m_self) {{ memset(&m_self, 0, sizeof(LDK{})); }}", ty, ty, ty).unwrap();
  21         writeln!(cpp_header_file, "\toperator LDK{}() && {{ LDK{} res = self; memset(&self, 0, sizeof(LDK{})); return res; }}", ty, ty, ty).unwrap();
  22         if has_destructor {
  23                 writeln!(cpp_header_file, "\t~{}() {{ {}_free(self); }}", ty, ty).unwrap();
  24                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ {}_free(self); self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty, ty).unwrap();
  25         } else {
  26                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty).unwrap();
  27         }
  28         writeln!(cpp_header_file, "\tLDK{}* operator &() {{ return &self; }}", ty).unwrap();
  29         writeln!(cpp_header_file, "\tLDK{}* operator ->() {{ return &self; }}", ty).unwrap();
  30         writeln!(cpp_header_file, "\tconst LDK{}* operator &() const {{ return &self; }}", ty).unwrap();
  31         writeln!(cpp_header_file, "\tconst LDK{}* operator ->() const {{ return &self; }}", ty).unwrap();
  32         writeln!(cpp_header_file, "}};").unwrap();
  33 }
  34
  35 /// Prints the docs from a given attribute list unless its tagged no export
  36 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
  37         for attr in attrs.iter() {
  38                 let tokens_clone = attr.tokens.clone();
  39                 let mut token_iter = tokens_clone.into_iter();
  40                 if let Some(token) = token_iter.next() {
  41                         match token {
  42                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  43                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
  44                                 },
  45                                 TokenTree::Group(_) => continue, // eg #[derive()]
  46                                 _ => unimplemented!(),
  47                         }
  48                 } else { continue; }
  49                 match attr.style {
  50                         syn::AttrStyle::Inner(_) => {
  51                                 match token_iter.next().unwrap() {
  52                                         TokenTree::Literal(lit) => {
  53                                                 // Drop the first and last chars from lit as they are always "
  54                                                 let doc = format!("{}", lit);
  55                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
  56                                         },
  57                                         _ => unimplemented!(),
  58                                 }
  59                         },
  60                         syn::AttrStyle::Outer => {
  61                                 match token_iter.next().unwrap() {
  62                                         TokenTree::Literal(lit) => {
  63                                                 // Drop the first and last chars from lit as they are always "
  64                                                 let doc = format!("{}", lit);
  65                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
  66                                         },
  67                                         _ => unimplemented!(),
  68                                 }
  69                         },
  70                 }
  71         }
  72 }
  73
  74 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
  75 /// including the closing parenthesis and return value, but not including the open bracket or any
  76 /// trailing semicolons.
  77 ///
  78 /// Usable both for a function definition and declaration.
  79 ///
  80 /// this_param is used when returning Self or accepting a self parameter, and should be the
  81 /// concrete, mapped type.
  82 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) {
  83         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
  84                         sig.abi.is_some() || sig.variadic.is_some() {
  85                 unimplemented!();
  86         }
  87         if sig.generics.lt_token.is_some() {
  88                 for generic in sig.generics.params.iter() {
  89                         match generic {
  90                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
  91                                         // We ignore these, if they're not on skipped args, we'll blow up
  92                                         // later, and lifetimes we just hope the C client enforces.
  93                                 },
  94                                 _ => unimplemented!(),
  95                         }
  96                 }
  97         }
  98
  99         let mut first_arg = true;
 100         let mut num_unused = 0;
 101         for inp in sig.inputs.iter() {
 102                 match inp {
 103                         syn::FnArg::Receiver(recv) => {
 104                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 105                                 write!(w, "this_arg: {}{}",
 106                                         match (self_ptr, recv.mutability.is_some()) {
 107                                                 (true, true) => "*mut ",
 108                                                 (true, false) => "*const ",
 109                                                 (false, true) => "&mut ",
 110                                                 (false, false) => "&",
 111                                         }, this_param).unwrap();
 112                                 assert!(first_arg);
 113                                 first_arg = false;
 114                         },
 115                         syn::FnArg::Typed(arg) => {
 116                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 117                                 if !arg.attrs.is_empty() { unimplemented!(); }
 118                                 // First get the c type so that we can check if it ends up being a reference:
 119                                 let mut c_type = Vec::new();
 120                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 121                                 match &*arg.pat {
 122                                         syn::Pat::Ident(ident) => {
 123                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 124                                                         unimplemented!();
 125                                                 }
 126                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 127                                                 first_arg = false;
 128                                         },
 129                                         syn::Pat::Wild(wild) => {
 130                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 131                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 132                                                 num_unused += 1;
 133                                         },
 134                                         _ => unimplemented!(),
 135                                 }
 136                                 w.write(&c_type).unwrap();
 137                         }
 138                 }
 139         }
 140         write!(w, ")").unwrap();
 141         match &sig.output {
 142                 syn::ReturnType::Type(_, rtype) => {
 143                         write!(w, " -> ").unwrap();
 144                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 145                                 if remaining_path.next().is_none() {
 146                                         write!(w, "{}", this_param).unwrap();
 147                                         return;
 148                                 }
 149                         }
 150                         if let syn::Type::Reference(r) = &**rtype {
 151                                 // We can't return a reference, cause we allocate things on the stack.
 152                                 types.write_c_type(w, &*r.elem, generics, true);
 153                         } else {
 154                                 types.write_c_type(w, &*rtype, generics, true);
 155                         }
 156                 },
 157                 _ => {},
 158         }
 159 }
 160
 161 /// Print the main part of a method declaration body, starting with a newline after the function
 162 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 163 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 164 /// parameters we mapped to/from C here.
 165 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) {
 166         let mut num_unused = 0;
 167         for inp in sig.inputs.iter() {
 168                 match inp {
 169                         syn::FnArg::Receiver(_) => {},
 170                         syn::FnArg::Typed(arg) => {
 171                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 172                                 if !arg.attrs.is_empty() { unimplemented!(); }
 173                                 macro_rules! write_new_var {
 174                                         ($ident: expr, $ty: expr) => {
 175                                                 if to_c {
 176                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 177                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 178                                                         }
 179                                                 } else {
 180                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 181                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 182                                                         }
 183                                                 }
 184                                         }
 185                                 }
 186                                 match &*arg.pat {
 187                                         syn::Pat::Ident(ident) => {
 188                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 189                                                         unimplemented!();
 190                                                 }
 191                                                 write_new_var!(ident.ident, *arg.ty);
 192                                         },
 193                                         syn::Pat::Wild(w) => {
 194                                                 if !w.attrs.is_empty() { unimplemented!(); }
 195                                                 write_new_var!(syn::Ident::new(&format!("unused_{}", num_unused), Span::call_site()), *arg.ty);
 196                                                 num_unused += 1;
 197                                         },
 198                                         _ => unimplemented!(),
 199                                 }
 200                         }
 201                 }
 202         }
 203         match &sig.output {
 204                 syn::ReturnType::Type(_, _) => {
 205                         write!(w, "let mut ret = ").unwrap();
 206                 },
 207                 _ => {},
 208         }
 209 }
 210
 211 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 212 /// final return statement returning the method's result. Should be followed by a single closing
 213 /// bracket.
 214 ///
 215 /// The return value is expected to be bound to a variable named `ret` which is available after a
 216 /// method-call-ending semicolon.
 217 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) {
 218         let mut first_arg = true;
 219         let mut num_unused = 0;
 220         for inp in sig.inputs.iter() {
 221                 match inp {
 222                         syn::FnArg::Receiver(recv) => {
 223                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 224                                 if to_c {
 225                                         write!(w, "self.this_arg").unwrap();
 226                                         first_arg = false;
 227                                 }
 228                         },
 229                         syn::FnArg::Typed(arg) => {
 230                                 if types.skip_arg(&*arg.ty, generics) {
 231                                         if !to_c {
 232                                                 if !first_arg {
 233                                                         write!(w, ", ").unwrap();
 234                                                 }
 235                                                 first_arg = false;
 236                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 237                                         }
 238                                         continue;
 239                                 }
 240                                 if !arg.attrs.is_empty() { unimplemented!(); }
 241                                 macro_rules! write_ident {
 242                                         ($ident: expr) => {
 243                                                 if !first_arg {
 244                                                         write!(w, ", ").unwrap();
 245                                                 }
 246                                                 first_arg = false;
 247                                                 if to_c {
 248                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 249                                                         write!(w, "{}", $ident).unwrap();
 250                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 251                                                 } else {
 252                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 253                                                         write!(w, "{}", $ident).unwrap();
 254                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 255                                                 }
 256                                         }
 257                                 }
 258                                 match &*arg.pat {
 259                                         syn::Pat::Ident(ident) => {
 260                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 261                                                         unimplemented!();
 262                                                 }
 263                                                 write_ident!(ident.ident);
 264                                         },
 265                                         syn::Pat::Wild(w) => {
 266                                                 if !w.attrs.is_empty() { unimplemented!(); }
 267                                                 write_ident!(format!("unused_{}", num_unused));
 268                                                 num_unused += 1;
 269                                         },
 270                                         _ => unimplemented!(),
 271                                 }
 272                         }
 273                 }
 274         }
 275         write!(w, ")").unwrap();
 276         match &sig.output {
 277                 syn::ReturnType::Type(_, rtype) => {
 278                         write!(w, ";\n\t{}", extra_indent).unwrap();
 279
 280                         let self_segs_iter = first_seg_self(&*rtype);
 281                         if to_c && first_seg_self(&*rtype).is_some() {
 282                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 283                                 write!(w, "ret").unwrap();
 284                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 285                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 286                                 write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
 287                         } else if to_c {
 288                                 let new_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), rtype, generics);
 289                                 if new_var {
 290                                         write!(w, "\n\t{}", extra_indent).unwrap();
 291                                 }
 292                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 293                                 write!(w, "ret").unwrap();
 294                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 295                         } else {
 296                                 let ret_returned = if let syn::Type::Reference(_) = &**rtype { true } else { false };
 297                                 let new_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), &rtype, generics, true);
 298                                 if new_var {
 299                                         write!(w, "\n\t{}", extra_indent).unwrap();
 300                                 }
 301                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 302                                 write!(w, "{}ret", if ret_returned && !new_var { "*" } else { "" }).unwrap();
 303                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 304                         }
 305                 }
 306                 _ => {},
 307         }
 308 }
 309
 310 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 311 /// greater-than symbols, if any generic parameters are defined.
 312 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 313         let mut gen_types = GenericTypes::new();
 314         assert!(gen_types.learn_generics(generics, types));
 315         if !generics.params.is_empty() {
 316                 write!(w, "<").unwrap();
 317                 for (idx, generic) in generics.params.iter().enumerate() {
 318                         match generic {
 319                                 syn::GenericParam::Type(type_param) => {
 320                                         let mut printed_param = false;
 321                                         for bound in type_param.bounds.iter() {
 322                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 323                                                         assert_simple_bound(&trait_bound);
 324                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
 325                                                         if printed_param {
 326                                                                 unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
 327                                                         }
 328                                                         printed_param = true;
 329                                                 }
 330                                         }
 331                                 },
 332                                 syn::GenericParam::Lifetime(lt) => {
 333                                         if concrete_lifetimes {
 334                                                 write!(w, "'static").unwrap();
 335                                         } else {
 336                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 337                                         }
 338                                 },
 339                                 _ => unimplemented!(),
 340                         }
 341                 }
 342                 write!(w, ">").unwrap();
 343         }
 344 }
 345
 346