_ 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, "/// The contents of {}", mangled_container).unwrap();
  47         writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap();
  48         if ok_type != "()" {
  49                 writeln!(w, "\t/// A pointer to the contents in the success state.").unwrap();
  50                 writeln!(w, "\t/// Reading from this pointer when `result_ok` is not set is undefined.").unwrap();
  51                 writeln!(w, "\tpub result: *mut {},", ok_type).unwrap();
  52         } else {
  53                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the OK variant").unwrap();
  54                 writeln!(w, "\tpub result: *mut std::ffi::c_void,").unwrap();
  55         }
  56         if err_type != "()" {
  57                 writeln!(w, "\t/// A pointer to the contents in the error state.").unwrap();
  58                 writeln!(w, "\t/// Reading from this pointer when `result_ok` is set is undefined.").unwrap();
  59                 writeln!(w, "\tpub err: *mut {},", err_type).unwrap();
  60         } else {
  61                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the Err variant").unwrap();
  62                 writeln!(w, "\tpub err: *mut std::ffi::c_void,").unwrap();
  63         }
  64         writeln!(w, "}}").unwrap();
  65         writeln!(w, "#[repr(C)]").unwrap();
  66         writeln!(w, "/// A {} represents the result of a fallible operation,", mangled_container).unwrap();
  67         writeln!(w, "/// containing a {} on success and a {} on failure.", ok_type, err_type).unwrap();
  68         writeln!(w, "/// `result_ok` indicates the overall state, and the contents are provided via `contents`.").unwrap();
  69         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
  70         writeln!(w, "\t/// The contents of this {}, accessible via either", mangled_container).unwrap();
  71         writeln!(w, "\t/// `err` or `result` depending on the state of `result_ok`.").unwrap();
  72         writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap();
  73         writeln!(w, "\t/// Whether this {} represents a success state.", mangled_container).unwrap();
  74         writeln!(w, "\tpub result_ok: bool,").unwrap();
  75         writeln!(w, "}}").unwrap();
  76
  77         writeln!(w, "#[no_mangle]").unwrap();
  78         if ok_type != "()" {
  79                 writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
  80                 writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap();
  81         } else {
  82                 writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
  83                 writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap();
  84         }
  85         writeln!(w, "\t{} {{", mangled_container).unwrap();
  86         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  87         if ok_type != "()" {
  88                 writeln!(w, "\t\t\tresult: Box::into_raw(Box::new(o)),").unwrap();
  89         } else {
  90                 writeln!(w, "\t\t\tresult: std::ptr::null_mut(),").unwrap();
  91         }
  92         writeln!(w, "\t\t}},").unwrap();
  93         writeln!(w, "\t\tresult_ok: true,").unwrap();
  94         writeln!(w, "\t}}").unwrap();
  95         writeln!(w, "}}").unwrap();
  96
  97         writeln!(w, "#[no_mangle]").unwrap();
  98         if err_type != "()" {
  99                 writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
 100                 writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap();
 101         } else {
 102                 writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
 103                 writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap();
 104         }
 105         writeln!(w, "\t{} {{", mangled_container).unwrap();
 106         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
 107         if err_type != "()" {
 108                 writeln!(w, "\t\t\terr: Box::into_raw(Box::new(e)),").unwrap();
 109         } else {
 110                 writeln!(w, "\t\t\terr: std::ptr::null_mut(),").unwrap();
 111         }
 112         writeln!(w, "\t\t}},").unwrap();
 113         writeln!(w, "\t\tresult_ok: false,").unwrap();
 114         writeln!(w, "\t}}").unwrap();
 115         writeln!(w, "}}").unwrap();
 116
 117         writeln!(w, "#[no_mangle]").unwrap();
 118         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 119         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 120         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 121         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 122         writeln!(w, "\t\tif self.result_ok {{").unwrap();
 123         if ok_type != "()" {
 124                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap();
 125                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap();
 126                 writeln!(w, "\t\t\t}}").unwrap();
 127         }
 128         writeln!(w, "\t\t}} else {{").unwrap();
 129         if err_type != "()" {
 130                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap();
 131                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap();
 132                 writeln!(w, "\t\t\t}}").unwrap();
 133         }
 134         writeln!(w, "\t\t}}").unwrap();
 135         writeln!(w, "\t}}").unwrap();
 136         writeln!(w, "}}").unwrap();
 137
 138         // TODO: Templates should use () now that they can, too
 139         let templ_ok_type = if ok_type != "()" { ok_type } else { "u8" };
 140         let templ_err_type = if err_type != "()" { err_type } else { "u8" };
 141
 142         writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", templ_ok_type, templ_err_type, mangled_container).unwrap();
 143         writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", templ_ok_type, templ_err_type).unwrap();
 144         writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
 145         if ok_type != "()" {
 146                 writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
 147                 writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap();
 148                 writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap();
 149         } else {
 150                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap();
 151                 writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap();
 152                 writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap();
 153         }
 154         writeln!(w, "\t\t}} else {{").unwrap();
 155         if err_type != "()" {
 156                 writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap();
 157                 writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap();
 158                 writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap();
 159         } else {
 160                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap();
 161                 writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap();
 162                 writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap();
 163         }
 164         writeln!(w, "\t\t}};").unwrap();
 165         writeln!(w, "\t\tSelf {{").unwrap();
 166         writeln!(w, "\t\t\tcontents,").unwrap();
 167         writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap();
 168         writeln!(w, "\t\t}}").unwrap();
 169         writeln!(w, "\t}}").unwrap();
 170         writeln!(w, "}}").unwrap();
 171
 172         if clonable {
 173                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 174                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 175                 writeln!(w, "\t\tif self.result_ok {{").unwrap();
 176                 writeln!(w, "\t\t\tSelf {{ result_ok: true, contents: {}Ptr {{", mangled_container).unwrap();
 177                 if ok_type != "()" {
 178                         writeln!(w, "\t\t\t\tresult: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.result }})))", ok_type).unwrap();
 179                 } else {
 180                         writeln!(w, "\t\t\t\tresult: std::ptr::null_mut()").unwrap();
 181                 }
 182                 writeln!(w, "\t\t\t}} }}").unwrap();
 183                 writeln!(w, "\t\t}} else {{").unwrap();
 184                 writeln!(w, "\t\t\tSelf {{ result_ok: false, contents: {}Ptr {{", mangled_container).unwrap();
 185                 if err_type != "()" {
 186                         writeln!(w, "\t\t\t\terr: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.err }})))", err_type).unwrap();
 187                 } else {
 188                         writeln!(w, "\t\t\t\terr: std::ptr::null_mut()").unwrap();
 189                 }
 190                 writeln!(w, "\t\t\t}} }}").unwrap();
 191                 writeln!(w, "\t\t}}").unwrap();
 192                 writeln!(w, "\t}}").unwrap();
 193                 writeln!(w, "}}").unwrap();
 194                 writeln!(w, "#[no_mangle]").unwrap();
 195                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 196                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 197                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 198         }
 199 }
 200
 201 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 202 pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 203         writeln!(w, "#[repr(C)]").unwrap();
 204         writeln!(w, "/// A dynamically-allocated array of {}s of arbitrary size.", inner_type).unwrap();
 205         writeln!(w, "/// This corresponds to std::vector in C++").unwrap();
 206         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 207         writeln!(w, "\t/// The elements in the array.").unwrap();
 208         writeln!(w, "\t/// If datalen is non-0 this must be a valid, non-NULL pointer allocated by malloc().").unwrap();
 209         writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
 210         writeln!(w, "\t/// The number of elements pointed to by `data`.").unwrap();
 211         writeln!(w, "\tpub datalen: usize").unwrap();
 212         writeln!(w, "}}").unwrap();
 213
 214         writeln!(w, "impl {} {{", mangled_container).unwrap();
 215         writeln!(w, "\t#[allow(unused)] pub(crate) fn into_rust(&mut self) -> Vec<{}> {{", inner_type).unwrap();
 216         writeln!(w, "\t\tif self.datalen == 0 {{ return Vec::new(); }}").unwrap();
 217         writeln!(w, "\t\tlet ret = unsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }}.into();").unwrap();
 218         writeln!(w, "\t\tself.data = std::ptr::null_mut();").unwrap();
 219         writeln!(w, "\t\tself.datalen = 0;").unwrap();
 220         writeln!(w, "\t\tret").unwrap();
 221         writeln!(w, "\t}}").unwrap();
 222         writeln!(w, "\t#[allow(unused)] pub(crate) fn as_slice(&self) -> &[{}] {{", inner_type).unwrap();
 223         writeln!(w, "\t\tunsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }}").unwrap();
 224         writeln!(w, "\t}}").unwrap();
 225         writeln!(w, "}}").unwrap();
 226
 227         writeln!(w, "impl From<Vec<{}>> for {} {{", inner_type, mangled_container).unwrap();
 228         writeln!(w, "\tfn from(v: Vec<{}>) -> Self {{", inner_type).unwrap();
 229         writeln!(w, "\t\tlet datalen = v.len();").unwrap();
 230         writeln!(w, "\t\tlet data = Box::into_raw(v.into_boxed_slice());").unwrap();
 231         writeln!(w, "\t\tSelf {{ datalen, data: unsafe {{ (*data).as_mut_ptr() }} }}").unwrap();
 232         writeln!(w, "\t}}").unwrap();
 233         writeln!(w, "}}").unwrap();
 234
 235         writeln!(w, "#[no_mangle]").unwrap();
 236         writeln!(w, "/// Frees the buffer pointed to by `data` if `datalen` is non-0.").unwrap();
 237         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 238         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 239         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 240         writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
 241         writeln!(w, "\t\tunsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
 242         writeln!(w, "\t}}").unwrap();
 243         writeln!(w, "}}").unwrap();
 244         if clonable {
 245                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 246                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 247                 writeln!(w, "\t\tlet mut res = Vec::new();").unwrap();
 248                 writeln!(w, "\t\tif self.datalen == 0 {{ return Self::from(res); }}").unwrap();
 249                 writeln!(w, "\t\tres.extend_from_slice(unsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }});").unwrap();
 250                 writeln!(w, "\t\tSelf::from(res)").unwrap();
 251                 writeln!(w, "\t}}").unwrap();
 252                 writeln!(w, "}}").unwrap();
 253         }
 254 }
 255
 256 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 257 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str, types: &[String], clonable: bool) {
 258         writeln!(w, "#[repr(C)]").unwrap();
 259         writeln!(w, "/// A tuple of {} elements. See the individual fields for the types contained.", types.len()).unwrap();
 260         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 261         for (idx, ty) in types.iter().enumerate() {
 262                 writeln!(w, "\t/// The element at position {}", idx).unwrap();
 263                 writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
 264         }
 265         writeln!(w, "}}").unwrap();
 266
 267         let mut tuple_str = "(".to_owned();
 268         for (idx, ty) in types.iter().enumerate() {
 269                 if idx != 0 { tuple_str += ", "; }
 270                 tuple_str += ty;
 271         }
 272         tuple_str += ")";
 273
 274         writeln!(w, "impl From<{}> for {} {{", tuple_str, mangled_container).unwrap();
 275         writeln!(w, "\tfn from (tup: {}) -> Self {{", tuple_str).unwrap();
 276         writeln!(w, "\t\tSelf {{").unwrap();
 277         for idx in 0..types.len() {
 278                 writeln!(w, "\t\t\t{}: tup.{},", ('a' as u8 + idx as u8) as char, idx).unwrap();
 279         }
 280         writeln!(w, "\t\t}}").unwrap();
 281         writeln!(w, "\t}}").unwrap();
 282         writeln!(w, "}}").unwrap();
 283         writeln!(w, "impl {} {{", mangled_container).unwrap();
 284         writeln!(w, "\t#[allow(unused)] pub(crate) fn to_rust(mut self) -> {} {{", tuple_str).unwrap();
 285         write!(w, "\t\t(").unwrap();
 286         for idx in 0..types.len() {
 287                 write!(w, "{}self.{}", if idx != 0 {", "} else {""}, ('a' as u8 + idx as u8) as char).unwrap();
 288         }
 289         writeln!(w, ")").unwrap();
 290         writeln!(w, "\t}}").unwrap();
 291         writeln!(w, "}}").unwrap();
 292
 293         if clonable {
 294                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 295                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 296                 writeln!(w, "\t\tSelf {{").unwrap();
 297                 for idx in 0..types.len() {
 298                         writeln!(w, "\t\t\t{}: self.{}.clone(),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
 299                 }
 300                 writeln!(w, "\t\t}}").unwrap();
 301                 writeln!(w, "\t}}").unwrap();
 302                 writeln!(w, "}}").unwrap();
 303                 writeln!(w, "#[no_mangle]").unwrap();
 304                 writeln!(w, "/// Creates a new tuple which has the same data as `orig`").unwrap();
 305                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 306                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 307         }
 308
 309         writeln!(w, "/// Creates a new {} from the contained elements.", mangled_container).unwrap();
 310         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
 311         for (idx, gen) in types.iter().enumerate() {
 312                 write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
 313                 //if !self.write_c_type_intern(&mut created_container, gen, generics, false, false, false) { return false; }
 314                 write!(w, "{}", gen).unwrap();
 315         }
 316         writeln!(w, ") -> {} {{", mangled_container).unwrap();
 317         write!(w, "\t{} {{ ", mangled_container).unwrap();
 318         for idx in 0..types.len() {
 319                 write!(w, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
 320         }
 321         writeln!(w, "}}\n}}\n").unwrap();
 322
 323         writeln!(w, "#[no_mangle]").unwrap();
 324         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 325         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 326 }
 327
 328 /// Writes out a C-callable concrete Option<A> struct and utility methods
 329 pub fn write_option_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 330         writeln!(w, "#[repr(C)]").unwrap();
 331         if clonable {
 332                 writeln!(w, "#[derive(Clone)]").unwrap();
 333         }
 334         writeln!(w, "/// An enum which can either contain a {} or not", inner_type).unwrap();
 335         writeln!(w, "pub enum {} {{", mangled_container).unwrap();
 336         writeln!(w, "\t/// When we're in this state, this {} contains a {}", mangled_container, inner_type).unwrap();
 337         writeln!(w, "\tSome({}),", inner_type).unwrap();
 338         writeln!(w, "\t/// When we're in this state, this {} contains nothing", mangled_container).unwrap();
 339         writeln!(w, "\tNone").unwrap();
 340         writeln!(w, "}}").unwrap();
 341
 342         writeln!(w, "impl {} {{", mangled_container).unwrap();
 343         writeln!(w, "\t#[allow(unused)] pub(crate) fn is_some(&self) -> bool {{").unwrap();
 344         writeln!(w, "\t\tif let Self::Some(_) = self {{ true }} else {{ false }}").unwrap();
 345         writeln!(w, "\t}}").unwrap();
 346         writeln!(w, "\t#[allow(unused)] pub(crate) fn take(mut self) -> {} {{", inner_type).unwrap();
 347         writeln!(w, "\t\tif let Self::Some(v) = self {{ v }} else {{ unreachable!() }}").unwrap();
 348         writeln!(w, "\t}}").unwrap();
 349         writeln!(w, "}}").unwrap();
 350
 351         writeln!(w, "#[no_mangle]").unwrap();
 352         writeln!(w, "/// Constructs a new {} containing a {}", mangled_container, inner_type).unwrap();
 353         writeln!(w, "pub extern \"C\" fn {}_some(o: {}) -> {} {{", mangled_container, inner_type, mangled_container).unwrap();
 354         writeln!(w, "\t{}::Some(o)", mangled_container).unwrap();
 355         writeln!(w, "}}").unwrap();
 356
 357         writeln!(w, "#[no_mangle]").unwrap();
 358         writeln!(w, "/// Constructs a new {} containing nothing", mangled_container).unwrap();
 359         writeln!(w, "pub extern \"C\" fn {}_none() -> {} {{", mangled_container, mangled_container).unwrap();
 360         writeln!(w, "\t{}::None", mangled_container).unwrap();
 361         writeln!(w, "}}").unwrap();
 362
 363         writeln!(w, "#[no_mangle]").unwrap();
 364         writeln!(w, "/// Frees any resources associated with the {}, if we are in the Some state", inner_type).unwrap();
 365         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 366         if clonable {
 367                 writeln!(w, "#[no_mangle]").unwrap();
 368                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 369                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 370                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 371         }
 372 }
 373
 374 /// Prints the docs from a given attribute list unless its tagged no export
 375 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
 376         for attr in attrs.iter() {
 377                 let tokens_clone = attr.tokens.clone();
 378                 let mut token_iter = tokens_clone.into_iter();
 379                 if let Some(token) = token_iter.next() {
 380                         match token {
 381                                 TokenTree::Punct(c) if c.as_char() == '=' => {
 382                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
 383                                 },
 384                                 TokenTree::Group(_) => continue, // eg #[derive()]
 385                                 _ => unimplemented!(),
 386                         }
 387                 } else { continue; }
 388                 match attr.style {
 389                         syn::AttrStyle::Inner(_) => {
 390                                 match token_iter.next().unwrap() {
 391                                         TokenTree::Literal(lit) => {
 392                                                 // Drop the first and last chars from lit as they are always "
 393                                                 let doc = format!("{}", lit);
 394                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 395                                         },
 396                                         _ => unimplemented!(),
 397                                 }
 398                         },
 399                         syn::AttrStyle::Outer => {
 400                                 match token_iter.next().unwrap() {
 401                                         TokenTree::Literal(lit) => {
 402                                                 // Drop the first and last chars from lit as they are always "
 403                                                 let doc = format!("{}", lit);
 404                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 405                                         },
 406                                         _ => unimplemented!(),
 407                                 }
 408                         },
 409                 }
 410         }
 411 }
 412
 413 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
 414 /// including the closing parenthesis and return value, but not including the open bracket or any
 415 /// trailing semicolons.
 416 ///
 417 /// Usable both for a function definition and declaration.
 418 ///
 419 /// this_param is used when returning Self or accepting a self parameter, and should be the
 420 /// concrete, mapped type.
 421 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) {
 422         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
 423                         sig.abi.is_some() || sig.variadic.is_some() {
 424                 unimplemented!();
 425         }
 426         if sig.generics.lt_token.is_some() {
 427                 for generic in sig.generics.params.iter() {
 428                         match generic {
 429                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
 430                                         // We ignore these, if they're not on skipped args, we'll blow up
 431                                         // later, and lifetimes we just hope the C client enforces.
 432                                 },
 433                                 _ => unimplemented!(),
 434                         }
 435                 }
 436         }
 437
 438         let mut first_arg = true;
 439         let mut num_unused = 0;
 440         for inp in sig.inputs.iter() {
 441                 match inp {
 442                         syn::FnArg::Receiver(recv) => {
 443                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 444                                 write!(w, "this_arg: {}{}",
 445                                         match (self_ptr, recv.mutability.is_some()) {
 446                                                 (true, true) => "*mut ",
 447                                                 (true, false) => "*const ",
 448                                                 (false, true) => "&mut ",
 449                                                 (false, false) => "&",
 450                                         }, this_param).unwrap();
 451                                 assert!(first_arg);
 452                                 first_arg = false;
 453                         },
 454                         syn::FnArg::Typed(arg) => {
 455                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 456                                 if !arg.attrs.is_empty() { unimplemented!(); }
 457                                 // First get the c type so that we can check if it ends up being a reference:
 458                                 let mut c_type = Vec::new();
 459                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 460                                 match &*arg.pat {
 461                                         syn::Pat::Ident(ident) => {
 462                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 463                                                         unimplemented!();
 464                                                 }
 465                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 466                                                 first_arg = false;
 467                                         },
 468                                         syn::Pat::Wild(wild) => {
 469                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 470                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 471                                                 num_unused += 1;
 472                                         },
 473                                         _ => unimplemented!(),
 474                                 }
 475                                 w.write(&c_type).unwrap();
 476                         }
 477                 }
 478         }
 479         write!(w, ")").unwrap();
 480         match &sig.output {
 481                 syn::ReturnType::Type(_, rtype) => {
 482                         write!(w, " -> ").unwrap();
 483                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 484                                 if remaining_path.next().is_none() {
 485                                         write!(w, "{}", this_param).unwrap();
 486                                         return;
 487                                 }
 488                         }
 489                         if let syn::Type::Reference(r) = &**rtype {
 490                                 // We can't return a reference, cause we allocate things on the stack.
 491                                 types.write_c_type(w, &*r.elem, generics, true);
 492                         } else {
 493                                 types.write_c_type(w, &*rtype, generics, true);
 494                         }
 495                 },
 496                 _ => {},
 497         }
 498 }
 499
 500 /// Print the main part of a method declaration body, starting with a newline after the function
 501 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 502 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 503 /// parameters we mapped to/from C here.
 504 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) {
 505         let mut num_unused = 0;
 506         for inp in sig.inputs.iter() {
 507                 match inp {
 508                         syn::FnArg::Receiver(_) => {},
 509                         syn::FnArg::Typed(arg) => {
 510                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 511                                 if !arg.attrs.is_empty() { unimplemented!(); }
 512                                 macro_rules! write_new_var {
 513                                         ($ident: expr, $ty: expr) => {
 514                                                 if to_c {
 515                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 516                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 517                                                         }
 518                                                 } else {
 519                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 520                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 521                                                         }
 522                                                 }
 523                                         }
 524                                 }
 525                                 match &*arg.pat {
 526                                         syn::Pat::Ident(ident) => {
 527                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 528                                                         unimplemented!();
 529                                                 }
 530                                                 write_new_var!(ident.ident, *arg.ty);
 531                                         },
 532                                         syn::Pat::Wild(w) => {
 533                                                 if !w.attrs.is_empty() { unimplemented!(); }
 534                                                 write_new_var!(syn::Ident::new(&format!("unused_{}", num_unused), Span::call_site()), *arg.ty);
 535                                                 num_unused += 1;
 536                                         },
 537                                         _ => unimplemented!(),
 538                                 }
 539                         }
 540                 }
 541         }
 542         match &sig.output {
 543                 syn::ReturnType::Type(_, _) => {
 544                         write!(w, "let mut ret = ").unwrap();
 545                 },
 546                 _ => {},
 547         }
 548 }
 549
 550 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 551 /// final return statement returning the method's result. Should be followed by a single closing
 552 /// bracket.
 553 ///
 554 /// The return value is expected to be bound to a variable named `ret` which is available after a
 555 /// method-call-ending semicolon.
 556 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) {
 557         let mut first_arg = true;
 558         let mut num_unused = 0;
 559         for inp in sig.inputs.iter() {
 560                 match inp {
 561                         syn::FnArg::Receiver(recv) => {
 562                                 if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 563                                 if to_c {
 564                                         write!(w, "self.this_arg").unwrap();
 565                                         first_arg = false;
 566                                 }
 567                         },
 568                         syn::FnArg::Typed(arg) => {
 569                                 if types.skip_arg(&*arg.ty, generics) {
 570                                         if !to_c {
 571                                                 if !first_arg {
 572                                                         write!(w, ", ").unwrap();
 573                                                 }
 574                                                 first_arg = false;
 575                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 576                                         }
 577                                         continue;
 578                                 }
 579                                 if !arg.attrs.is_empty() { unimplemented!(); }
 580                                 macro_rules! write_ident {
 581                                         ($ident: expr) => {
 582                                                 if !first_arg {
 583                                                         write!(w, ", ").unwrap();
 584                                                 }
 585                                                 first_arg = false;
 586                                                 if to_c {
 587                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 588                                                         write!(w, "{}", $ident).unwrap();
 589                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 590                                                 } else {
 591                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 592                                                         write!(w, "{}", $ident).unwrap();
 593                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 594                                                 }
 595                                         }
 596                                 }
 597                                 match &*arg.pat {
 598                                         syn::Pat::Ident(ident) => {
 599                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 600                                                         unimplemented!();
 601                                                 }
 602                                                 write_ident!(ident.ident);
 603                                         },
 604                                         syn::Pat::Wild(w) => {
 605                                                 if !w.attrs.is_empty() { unimplemented!(); }
 606                                                 write_ident!(format!("unused_{}", num_unused));
 607                                                 num_unused += 1;
 608                                         },
 609                                         _ => unimplemented!(),
 610                                 }
 611                         }
 612                 }
 613         }
 614         write!(w, ")").unwrap();
 615         match &sig.output {
 616                 syn::ReturnType::Type(_, rtype) => {
 617                         write!(w, ";\n\t{}", extra_indent).unwrap();
 618
 619                         let self_segs_iter = first_seg_self(&*rtype);
 620                         if to_c && first_seg_self(&*rtype).is_some() {
 621                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 622                                 write!(w, "ret").unwrap();
 623                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 624                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 625                                 write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
 626                         } else if to_c {
 627                                 let new_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), rtype, generics);
 628                                 if new_var {
 629                                         write!(w, "\n\t{}", extra_indent).unwrap();
 630                                 }
 631                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 632                                 write!(w, "ret").unwrap();
 633                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 634                         } else {
 635                                 let ret_returned = if let syn::Type::Reference(_) = &**rtype { true } else { false };
 636                                 let new_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("ret", Span::call_site()), &rtype, generics, true);
 637                                 if new_var {
 638                                         write!(w, "\n\t{}", extra_indent).unwrap();
 639                                 }
 640                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 641                                 write!(w, "{}ret", if ret_returned && !new_var { "*" } else { "" }).unwrap();
 642                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 643                         }
 644                 }
 645                 _ => {},
 646         }
 647 }
 648
 649 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 650 /// greater-than symbols, if any generic parameters are defined.
 651 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 652         let mut gen_types = GenericTypes::new();
 653         assert!(gen_types.learn_generics(generics, types));
 654         if !generics.params.is_empty() {
 655                 write!(w, "<").unwrap();
 656                 for (idx, generic) in generics.params.iter().enumerate() {
 657                         match generic {
 658                                 syn::GenericParam::Type(type_param) => {
 659                                         let mut printed_param = false;
 660                                         for bound in type_param.bounds.iter() {
 661                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 662                                                         assert_simple_bound(&trait_bound);
 663                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
 664                                                         if printed_param {
 665                                                                 unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
 666                                                         }
 667                                                         printed_param = true;
 668                                                 }
 669                                         }
 670                                 },
 671                                 syn::GenericParam::Lifetime(lt) => {
 672                                         if concrete_lifetimes {
 673                                                 write!(w, "'static").unwrap();
 674                                         } else {
 675                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 676                                         }
 677                                 },
 678                                 _ => unimplemented!(),
 679                         }
 680                 }
 681                 write!(w, ">").unwrap();
 682         }
 683 }
 684
 685