_ 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
  15 use proc_macro2::TokenTree;
  16 use quote::format_ident;
  17
  18 use crate::types::*;
  19
  20 /// Writes out a C++ wrapper class for the given type, which contains various utilities to access
  21 /// the underlying C-mapped type safely avoiding some common memory management issues by handling
  22 /// resource-freeing and prevending accidental raw copies.
  23 pub fn write_cpp_wrapper(cpp_header_file: &mut File, ty: &str, has_destructor: bool, trait_methods: Option<Vec<(String, String)>>) {
  24         writeln!(cpp_header_file, "class {} {{", ty).unwrap();
  25         writeln!(cpp_header_file, "private:").unwrap();
  26         writeln!(cpp_header_file, "\tLDK{} self;", ty).unwrap();
  27         writeln!(cpp_header_file, "public:").unwrap();
  28         writeln!(cpp_header_file, "\t{}(const {}&) = delete;", ty, ty).unwrap();
  29         writeln!(cpp_header_file, "\t{}({}&& o) : self(o.self) {{ memset(&o, 0, sizeof({})); }}", ty, ty, ty).unwrap();
  30         writeln!(cpp_header_file, "\t{}(LDK{}&& m_self) : self(m_self) {{ memset(&m_self, 0, sizeof(LDK{})); }}", ty, ty, ty).unwrap();
  31         writeln!(cpp_header_file, "\toperator LDK{}() && {{ LDK{} res = self; memset(&self, 0, sizeof(LDK{})); return res; }}", ty, ty, ty).unwrap();
  32         if has_destructor {
  33                 writeln!(cpp_header_file, "\t~{}() {{ {}_free(self); }}", ty, ty).unwrap();
  34                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ {}_free(self); self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty, ty).unwrap();
  35         } else {
  36                 writeln!(cpp_header_file, "\t{}& operator=({}&& o) {{ self = o.self; memset(&o, 0, sizeof({})); return *this; }}", ty, ty, ty).unwrap();
  37         }
  38         writeln!(cpp_header_file, "\tLDK{}* operator &() {{ return &self; }}", ty).unwrap();
  39         writeln!(cpp_header_file, "\tLDK{}* operator ->() {{ return &self; }}", ty).unwrap();
  40         writeln!(cpp_header_file, "\tconst LDK{}* operator &() const {{ return &self; }}", ty).unwrap();
  41         writeln!(cpp_header_file, "\tconst LDK{}* operator ->() const {{ return &self; }}", ty).unwrap();
  42         if let Some(methods) = trait_methods {
  43                 for (meth_name, meth_docs) in methods {
  44                         cpp_header_file.write_all(meth_docs.as_bytes()).unwrap();
  45                         // Note that we have zero logic to print C/C__ code for a given function. Instead, we
  46                         // simply use sed to replace the following in genbindings.sh
  47                         writeln!(cpp_header_file, "XXX {} {}", ty, meth_name).unwrap();
  48                 }
  49         }
  50         writeln!(cpp_header_file, "}};").unwrap();
  51 }
  52
  53 /// Writes out a C-callable concrete Result<A, B> struct and utility methods
  54 pub fn write_result_block<W: std::io::Write>(w: &mut W, mangled_container: &str, ok_type: &str, err_type: &str, clonable: bool) {
  55         writeln!(w, "#[repr(C)]").unwrap();
  56         writeln!(w, "/// The contents of {}", mangled_container).unwrap();
  57         writeln!(w, "pub union {}Ptr {{", mangled_container).unwrap();
  58         if ok_type != "()" {
  59                 writeln!(w, "\t/// A pointer to the contents in the success state.").unwrap();
  60                 writeln!(w, "\t/// Reading from this pointer when `result_ok` is not set is undefined.").unwrap();
  61                 writeln!(w, "\tpub result: *mut {},", ok_type).unwrap();
  62         } else {
  63                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the OK variant").unwrap();
  64                 writeln!(w, "\tpub result: *mut std::ffi::c_void,").unwrap();
  65         }
  66         if err_type != "()" {
  67                 writeln!(w, "\t/// A pointer to the contents in the error state.").unwrap();
  68                 writeln!(w, "\t/// Reading from this pointer when `result_ok` is set is undefined.").unwrap();
  69                 writeln!(w, "\tpub err: *mut {},", err_type).unwrap();
  70         } else {
  71                 writeln!(w, "\t/// Note that this value is always NULL, as there are no contents in the Err variant").unwrap();
  72                 writeln!(w, "\tpub err: *mut std::ffi::c_void,").unwrap();
  73         }
  74         writeln!(w, "}}").unwrap();
  75         writeln!(w, "#[repr(C)]").unwrap();
  76         writeln!(w, "/// A {} represents the result of a fallible operation,", mangled_container).unwrap();
  77         writeln!(w, "/// containing a {} on success and a {} on failure.", ok_type, err_type).unwrap();
  78         writeln!(w, "/// `result_ok` indicates the overall state, and the contents are provided via `contents`.").unwrap();
  79         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
  80         writeln!(w, "\t/// The contents of this {}, accessible via either", mangled_container).unwrap();
  81         writeln!(w, "\t/// `err` or `result` depending on the state of `result_ok`.").unwrap();
  82         writeln!(w, "\tpub contents: {}Ptr,", mangled_container).unwrap();
  83         writeln!(w, "\t/// Whether this {} represents a success state.", mangled_container).unwrap();
  84         writeln!(w, "\tpub result_ok: bool,").unwrap();
  85         writeln!(w, "}}").unwrap();
  86
  87         writeln!(w, "#[no_mangle]").unwrap();
  88         if ok_type != "()" {
  89                 writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
  90                 writeln!(w, "pub extern \"C\" fn {}_ok(o: {}) -> {} {{", mangled_container, ok_type, mangled_container).unwrap();
  91         } else {
  92                 writeln!(w, "/// Creates a new {} in the success state.", mangled_container).unwrap();
  93                 writeln!(w, "pub extern \"C\" fn {}_ok() -> {} {{", mangled_container, mangled_container).unwrap();
  94         }
  95         writeln!(w, "\t{} {{", mangled_container).unwrap();
  96         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
  97         if ok_type != "()" {
  98                 writeln!(w, "\t\t\tresult: Box::into_raw(Box::new(o)),").unwrap();
  99         } else {
 100                 writeln!(w, "\t\t\tresult: std::ptr::null_mut(),").unwrap();
 101         }
 102         writeln!(w, "\t\t}},").unwrap();
 103         writeln!(w, "\t\tresult_ok: true,").unwrap();
 104         writeln!(w, "\t}}").unwrap();
 105         writeln!(w, "}}").unwrap();
 106
 107         writeln!(w, "#[no_mangle]").unwrap();
 108         if err_type != "()" {
 109                 writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
 110                 writeln!(w, "pub extern \"C\" fn {}_err(e: {}) -> {} {{", mangled_container, err_type, mangled_container).unwrap();
 111         } else {
 112                 writeln!(w, "/// Creates a new {} in the error state.", mangled_container).unwrap();
 113                 writeln!(w, "pub extern \"C\" fn {}_err() -> {} {{", mangled_container, mangled_container).unwrap();
 114         }
 115         writeln!(w, "\t{} {{", mangled_container).unwrap();
 116         writeln!(w, "\t\tcontents: {}Ptr {{", mangled_container).unwrap();
 117         if err_type != "()" {
 118                 writeln!(w, "\t\t\terr: Box::into_raw(Box::new(e)),").unwrap();
 119         } else {
 120                 writeln!(w, "\t\t\terr: std::ptr::null_mut(),").unwrap();
 121         }
 122         writeln!(w, "\t\t}},").unwrap();
 123         writeln!(w, "\t\tresult_ok: false,").unwrap();
 124         writeln!(w, "\t}}").unwrap();
 125         writeln!(w, "}}").unwrap();
 126
 127         writeln!(w, "#[no_mangle]").unwrap();
 128         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 129         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 130         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 131         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 132         writeln!(w, "\t\tif self.result_ok {{").unwrap();
 133         if ok_type != "()" {
 134                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap();
 135                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap();
 136                 writeln!(w, "\t\t\t}}").unwrap();
 137         }
 138         writeln!(w, "\t\t}} else {{").unwrap();
 139         if err_type != "()" {
 140                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap();
 141                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap();
 142                 writeln!(w, "\t\t\t}}").unwrap();
 143         }
 144         writeln!(w, "\t\t}}").unwrap();
 145         writeln!(w, "\t}}").unwrap();
 146         writeln!(w, "}}").unwrap();
 147
 148         writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", ok_type, err_type, mangled_container).unwrap();
 149         writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", ok_type, err_type).unwrap();
 150         writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
 151         if ok_type != "()" {
 152                 writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
 153                 writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap();
 154                 writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap();
 155         } else {
 156                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap();
 157                 writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap();
 158                 writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap();
 159         }
 160         writeln!(w, "\t\t}} else {{").unwrap();
 161         if err_type != "()" {
 162                 writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap();
 163                 writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap();
 164                 writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap();
 165         } else {
 166                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap();
 167                 writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap();
 168                 writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap();
 169         }
 170         writeln!(w, "\t\t}};").unwrap();
 171         writeln!(w, "\t\tSelf {{").unwrap();
 172         writeln!(w, "\t\t\tcontents,").unwrap();
 173         writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap();
 174         writeln!(w, "\t\t}}").unwrap();
 175         writeln!(w, "\t}}").unwrap();
 176         writeln!(w, "}}").unwrap();
 177
 178         if clonable {
 179                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 180                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 181                 writeln!(w, "\t\tif self.result_ok {{").unwrap();
 182                 writeln!(w, "\t\t\tSelf {{ result_ok: true, contents: {}Ptr {{", mangled_container).unwrap();
 183                 if ok_type != "()" {
 184                         writeln!(w, "\t\t\t\tresult: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.result }})))", ok_type).unwrap();
 185                 } else {
 186                         writeln!(w, "\t\t\t\tresult: std::ptr::null_mut()").unwrap();
 187                 }
 188                 writeln!(w, "\t\t\t}} }}").unwrap();
 189                 writeln!(w, "\t\t}} else {{").unwrap();
 190                 writeln!(w, "\t\t\tSelf {{ result_ok: false, contents: {}Ptr {{", mangled_container).unwrap();
 191                 if err_type != "()" {
 192                         writeln!(w, "\t\t\t\terr: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.err }})))", err_type).unwrap();
 193                 } else {
 194                         writeln!(w, "\t\t\t\terr: std::ptr::null_mut()").unwrap();
 195                 }
 196                 writeln!(w, "\t\t\t}} }}").unwrap();
 197                 writeln!(w, "\t\t}}").unwrap();
 198                 writeln!(w, "\t}}").unwrap();
 199                 writeln!(w, "}}").unwrap();
 200                 writeln!(w, "#[no_mangle]").unwrap();
 201                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 202                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 203                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 204         }
 205 }
 206
 207 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 208 pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 209         writeln!(w, "#[repr(C)]").unwrap();
 210         writeln!(w, "/// A dynamically-allocated array of {}s of arbitrary size.", inner_type).unwrap();
 211         writeln!(w, "/// This corresponds to std::vector in C++").unwrap();
 212         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 213         writeln!(w, "\t/// The elements in the array.").unwrap();
 214         writeln!(w, "\t/// If datalen is non-0 this must be a valid, non-NULL pointer allocated by malloc().").unwrap();
 215         writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
 216         writeln!(w, "\t/// The number of elements pointed to by `data`.").unwrap();
 217         writeln!(w, "\tpub datalen: usize").unwrap();
 218         writeln!(w, "}}").unwrap();
 219
 220         writeln!(w, "impl {} {{", mangled_container).unwrap();
 221         writeln!(w, "\t#[allow(unused)] pub(crate) fn into_rust(&mut self) -> Vec<{}> {{", inner_type).unwrap();
 222         writeln!(w, "\t\tif self.datalen == 0 {{ return Vec::new(); }}").unwrap();
 223         writeln!(w, "\t\tlet ret = unsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }}.into();").unwrap();
 224         writeln!(w, "\t\tself.data = std::ptr::null_mut();").unwrap();
 225         writeln!(w, "\t\tself.datalen = 0;").unwrap();
 226         writeln!(w, "\t\tret").unwrap();
 227         writeln!(w, "\t}}").unwrap();
 228         writeln!(w, "\t#[allow(unused)] pub(crate) fn as_slice(&self) -> &[{}] {{", inner_type).unwrap();
 229         writeln!(w, "\t\tunsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }}").unwrap();
 230         writeln!(w, "\t}}").unwrap();
 231         writeln!(w, "}}").unwrap();
 232
 233         writeln!(w, "impl From<Vec<{}>> for {} {{", inner_type, mangled_container).unwrap();
 234         writeln!(w, "\tfn from(v: Vec<{}>) -> Self {{", inner_type).unwrap();
 235         writeln!(w, "\t\tlet datalen = v.len();").unwrap();
 236         writeln!(w, "\t\tlet data = Box::into_raw(v.into_boxed_slice());").unwrap();
 237         writeln!(w, "\t\tSelf {{ datalen, data: unsafe {{ (*data).as_mut_ptr() }} }}").unwrap();
 238         writeln!(w, "\t}}").unwrap();
 239         writeln!(w, "}}").unwrap();
 240
 241         writeln!(w, "#[no_mangle]").unwrap();
 242         writeln!(w, "/// Frees the buffer pointed to by `data` if `datalen` is non-0.").unwrap();
 243         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 244         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 245         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 246         writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
 247         writeln!(w, "\t\tunsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
 248         writeln!(w, "\t}}").unwrap();
 249         writeln!(w, "}}").unwrap();
 250         if clonable {
 251                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 252                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 253                 writeln!(w, "\t\tlet mut res = Vec::new();").unwrap();
 254                 writeln!(w, "\t\tif self.datalen == 0 {{ return Self::from(res); }}").unwrap();
 255                 writeln!(w, "\t\tres.extend_from_slice(unsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }});").unwrap();
 256                 writeln!(w, "\t\tSelf::from(res)").unwrap();
 257                 writeln!(w, "\t}}").unwrap();
 258                 writeln!(w, "}}").unwrap();
 259         }
 260 }
 261
 262 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 263 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str, types: &[String], clonable: bool) {
 264         writeln!(w, "#[repr(C)]").unwrap();
 265         writeln!(w, "/// A tuple of {} elements. See the individual fields for the types contained.", types.len()).unwrap();
 266         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 267         for (idx, ty) in types.iter().enumerate() {
 268                 writeln!(w, "\t/// The element at position {}", idx).unwrap();
 269                 writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
 270         }
 271         writeln!(w, "}}").unwrap();
 272
 273         let mut tuple_str = "(".to_owned();
 274         for (idx, ty) in types.iter().enumerate() {
 275                 if idx != 0 { tuple_str += ", "; }
 276                 tuple_str += ty;
 277         }
 278         tuple_str += ")";
 279
 280         writeln!(w, "impl From<{}> for {} {{", tuple_str, mangled_container).unwrap();
 281         writeln!(w, "\tfn from (tup: {}) -> Self {{", tuple_str).unwrap();
 282         writeln!(w, "\t\tSelf {{").unwrap();
 283         for idx in 0..types.len() {
 284                 writeln!(w, "\t\t\t{}: tup.{},", ('a' as u8 + idx as u8) as char, idx).unwrap();
 285         }
 286         writeln!(w, "\t\t}}").unwrap();
 287         writeln!(w, "\t}}").unwrap();
 288         writeln!(w, "}}").unwrap();
 289         writeln!(w, "impl {} {{", mangled_container).unwrap();
 290         writeln!(w, "\t#[allow(unused)] pub(crate) fn to_rust(mut self) -> {} {{", tuple_str).unwrap();
 291         write!(w, "\t\t(").unwrap();
 292         for idx in 0..types.len() {
 293                 write!(w, "{}self.{}", if idx != 0 {", "} else {""}, ('a' as u8 + idx as u8) as char).unwrap();
 294         }
 295         writeln!(w, ")").unwrap();
 296         writeln!(w, "\t}}").unwrap();
 297         writeln!(w, "}}").unwrap();
 298
 299         if clonable {
 300                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 301                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 302                 writeln!(w, "\t\tSelf {{").unwrap();
 303                 for idx in 0..types.len() {
 304                         writeln!(w, "\t\t\t{}: self.{}.clone(),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
 305                 }
 306                 writeln!(w, "\t\t}}").unwrap();
 307                 writeln!(w, "\t}}").unwrap();
 308                 writeln!(w, "}}").unwrap();
 309                 writeln!(w, "#[no_mangle]").unwrap();
 310                 writeln!(w, "/// Creates a new tuple which has the same data as `orig`").unwrap();
 311                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 312                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 313         }
 314
 315         writeln!(w, "/// Creates a new {} from the contained elements.", mangled_container).unwrap();
 316         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
 317         for (idx, gen) in types.iter().enumerate() {
 318                 write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
 319                 //if !self.write_c_type_intern(&mut created_container, gen, generics, false, false, false) { return false; }
 320                 write!(w, "{}", gen).unwrap();
 321         }
 322         writeln!(w, ") -> {} {{", mangled_container).unwrap();
 323         write!(w, "\t{} {{ ", mangled_container).unwrap();
 324         for idx in 0..types.len() {
 325                 write!(w, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
 326         }
 327         writeln!(w, "}}\n}}\n").unwrap();
 328
 329         writeln!(w, "#[no_mangle]").unwrap();
 330         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 331         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 332 }
 333
 334 /// Writes out a C-callable concrete Option<A> struct and utility methods
 335 pub fn write_option_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 336         writeln!(w, "#[repr(C)]").unwrap();
 337         if clonable {
 338                 writeln!(w, "#[derive(Clone)]").unwrap();
 339         }
 340         writeln!(w, "/// An enum which can either contain a {} or not", inner_type).unwrap();
 341         writeln!(w, "pub enum {} {{", mangled_container).unwrap();
 342         writeln!(w, "\t/// When we're in this state, this {} contains a {}", mangled_container, inner_type).unwrap();
 343         writeln!(w, "\tSome({}),", inner_type).unwrap();
 344         writeln!(w, "\t/// When we're in this state, this {} contains nothing", mangled_container).unwrap();
 345         writeln!(w, "\tNone").unwrap();
 346         writeln!(w, "}}").unwrap();
 347
 348         writeln!(w, "impl {} {{", mangled_container).unwrap();
 349         writeln!(w, "\t#[allow(unused)] pub(crate) fn is_some(&self) -> bool {{").unwrap();
 350         writeln!(w, "\t\tif let Self::Some(_) = self {{ true }} else {{ false }}").unwrap();
 351         writeln!(w, "\t}}").unwrap();
 352         writeln!(w, "\t#[allow(unused)] pub(crate) fn take(mut self) -> {} {{", inner_type).unwrap();
 353         writeln!(w, "\t\tif let Self::Some(v) = self {{ v }} else {{ unreachable!() }}").unwrap();
 354         writeln!(w, "\t}}").unwrap();
 355         writeln!(w, "}}").unwrap();
 356
 357         writeln!(w, "#[no_mangle]").unwrap();
 358         writeln!(w, "/// Constructs a new {} containing a {}", mangled_container, inner_type).unwrap();
 359         writeln!(w, "pub extern \"C\" fn {}_some(o: {}) -> {} {{", mangled_container, inner_type, mangled_container).unwrap();
 360         writeln!(w, "\t{}::Some(o)", mangled_container).unwrap();
 361         writeln!(w, "}}").unwrap();
 362
 363         writeln!(w, "#[no_mangle]").unwrap();
 364         writeln!(w, "/// Constructs a new {} containing nothing", mangled_container).unwrap();
 365         writeln!(w, "pub extern \"C\" fn {}_none() -> {} {{", mangled_container, mangled_container).unwrap();
 366         writeln!(w, "\t{}::None", mangled_container).unwrap();
 367         writeln!(w, "}}").unwrap();
 368
 369         writeln!(w, "#[no_mangle]").unwrap();
 370         writeln!(w, "/// Frees any resources associated with the {}, if we are in the Some state", inner_type).unwrap();
 371         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 372         if clonable {
 373                 writeln!(w, "#[no_mangle]").unwrap();
 374                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 375                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 376                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ orig.clone() }}", mangled_container, mangled_container, mangled_container).unwrap();
 377         }
 378 }
 379
 380 /// Prints the docs from a given attribute list unless its tagged no export
 381 pub fn writeln_fn_docs<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, args: I, ret: &syn::ReturnType) where I: Iterator<Item = &'a syn::FnArg> {
 382         writeln_docs_impl(w, attrs, prefix, Some((types, generics,
 383                 args.filter_map(|arg| if let syn::FnArg::Typed(ty) = arg {
 384                                 if let syn::Pat::Ident(id) = &*ty.pat {
 385                                         Some((id.ident.to_string(), &*ty.ty))
 386                                 } else { unimplemented!() }
 387                         } else { None }),
 388                 if let syn::ReturnType::Type(_, ty) = ret { Some(&**ty) } else { None },
 389                 None
 390         )));
 391 }
 392
 393 /// Prints the docs from a given attribute list unless its tagged no export
 394 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
 395         writeln_docs_impl(w, attrs, prefix, None::<(_, _, std::vec::Drain<'_, (String, &syn::Type)>, _, _)>);
 396 }
 397
 398 pub fn writeln_arg_docs<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, args: I, ret: Option<&syn::Type>) where I: Iterator<Item = (String, &'a syn::Type)> {
 399         writeln_docs_impl(w, attrs, prefix, Some((types, generics, args, ret, None)))
 400 }
 401
 402 pub fn writeln_field_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, types: &mut TypeResolver, generics: Option<&GenericTypes>, field: &syn::Type) {
 403         writeln_docs_impl(w, attrs, prefix, Some((types, generics, vec![].drain(..), None, Some(field))))
 404 }
 405
 406 /// Prints the docs from a given attribute list unless its tagged no export
 407 fn writeln_docs_impl<'a, W: std::io::Write, I>(w: &mut W, attrs: &[syn::Attribute], prefix: &str, method_args_ret: Option<(&mut TypeResolver, Option<&GenericTypes>, I, Option<&syn::Type>, Option<&syn::Type>)>) where I: Iterator<Item = (String, &'a syn::Type)> {
 408         for attr in attrs.iter() {
 409                 let tokens_clone = attr.tokens.clone();
 410                 let mut token_iter = tokens_clone.into_iter();
 411                 if let Some(token) = token_iter.next() {
 412                         match token {
 413                                 TokenTree::Punct(c) if c.as_char() == '=' => {
 414                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
 415                                 },
 416                                 TokenTree::Group(_) => continue, // eg #[derive()]
 417                                 _ => unimplemented!(),
 418                         }
 419                 } else { continue; }
 420                 match attr.style {
 421                         syn::AttrStyle::Inner(_) => {
 422                                 match token_iter.next().unwrap() {
 423                                         TokenTree::Literal(lit) => {
 424                                                 // Drop the first and last chars from lit as they are always "
 425                                                 let doc = format!("{}", lit);
 426                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 427                                         },
 428                                         _ => unimplemented!(),
 429                                 }
 430                         },
 431                         syn::AttrStyle::Outer => {
 432                                 match token_iter.next().unwrap() {
 433                                         TokenTree::Literal(lit) => {
 434                                                 // Drop the first and last chars from lit as they are always "
 435                                                 let doc = format!("{}", lit);
 436                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 437                                         },
 438                                         _ => unimplemented!(),
 439                                 }
 440                         },
 441                 }
 442         }
 443         if let Some((types, generics, inp, outp, field)) = method_args_ret {
 444                 let mut nullable_found = false;
 445                 for (name, inp) in inp {
 446                         if types.skip_arg(inp, generics) { continue; }
 447                         if if let syn::Type::Reference(syn::TypeReference { elem, .. }) = inp {
 448                                 if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 449                                         types.is_path_transparent_container(path, generics, true)
 450                                 } else { false }
 451                         } else if let syn::Type::Path(syn::TypePath { ref path, .. }) = inp {
 452                                 types.is_path_transparent_container(path, generics, true)
 453                         } else { false } {
 454                                 // Note downstream clients match this text exactly so any changes may require
 455                                 // changes in the Java and Swift bindings, at least.
 456                                 if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 457                                 nullable_found = true;
 458                                 writeln!(w, "{}/// Note that {} (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix, name).unwrap();
 459                         }
 460                 }
 461                 if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = outp {
 462                         if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 463                                 types.is_path_transparent_container(path, generics, true)
 464                         } else { false }
 465                 } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = outp {
 466                         types.is_path_transparent_container(path, generics, true)
 467                 } else { false } {
 468                         // Note downstream clients match this text exactly so any changes may require
 469                         // changes in the Java and Swift bindings, at least.
 470                         if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 471                         nullable_found = true;
 472                         writeln!(w, "{}/// Note that the return value (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
 473                 }
 474                 if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = field {
 475                         if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 476                                 types.is_path_transparent_container(path, generics, true)
 477                         } else { false }
 478                 } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = field {
 479                         types.is_path_transparent_container(path, generics, true)
 480                 } else { false } {
 481                         // Note downstream clients match this text exactly so any changes may require
 482                         // changes in the Java and Swift bindings, at least.
 483                         if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 484                         writeln!(w, "{}/// Note that this (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
 485                 }
 486         }
 487
 488 }
 489
 490 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
 491 /// including the closing parenthesis and return value, but not including the open bracket or any
 492 /// trailing semicolons.
 493 ///
 494 /// Usable both for a function definition and declaration.
 495 ///
 496 /// this_param is used when returning Self or accepting a self parameter, and should be the
 497 /// concrete, mapped type.
 498 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) {
 499         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
 500                         sig.abi.is_some() || sig.variadic.is_some() {
 501                 unimplemented!();
 502         }
 503         if sig.generics.lt_token.is_some() {
 504                 for generic in sig.generics.params.iter() {
 505                         match generic {
 506                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
 507                                         // We ignore these, if they're not on skipped args, we'll blow up
 508                                         // later, and lifetimes we just hope the C client enforces.
 509                                 },
 510                                 _ => unimplemented!(),
 511                         }
 512                 }
 513         }
 514
 515         let mut first_arg = true;
 516         let mut num_unused = 0;
 517         for inp in sig.inputs.iter() {
 518                 match inp {
 519                         syn::FnArg::Receiver(recv) => {
 520                                 if !recv.attrs.is_empty() { unimplemented!(); }
 521                                 write!(w, "{}this_arg: {}{}", if recv.reference.is_none() { "mut " } else { "" },
 522                                         if recv.reference.is_some() {
 523                                                 match (self_ptr, recv.mutability.is_some()) {
 524                                                         (true, true) => "*mut ",
 525                                                         (true, false) => "*const ",
 526                                                         (false, true) => "&mut ",
 527                                                         (false, false) => "&",
 528                                                 }
 529                                         } else { "" }, this_param).unwrap();
 530                                 assert!(first_arg);
 531                                 first_arg = false;
 532                         },
 533                         syn::FnArg::Typed(arg) => {
 534                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 535                                 if !arg.attrs.is_empty() { unimplemented!(); }
 536                                 // First get the c type so that we can check if it ends up being a reference:
 537                                 let mut c_type = Vec::new();
 538                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 539                                 match &*arg.pat {
 540                                         syn::Pat::Ident(ident) => {
 541                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 542                                                         unimplemented!();
 543                                                 }
 544                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 545                                                 first_arg = false;
 546                                         },
 547                                         syn::Pat::Wild(wild) => {
 548                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 549                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 550                                                 num_unused += 1;
 551                                         },
 552                                         _ => unimplemented!(),
 553                                 }
 554                                 w.write(&c_type).unwrap();
 555                         }
 556                 }
 557         }
 558         write!(w, ")").unwrap();
 559         match &sig.output {
 560                 syn::ReturnType::Type(_, rtype) => {
 561                         write!(w, " -> ").unwrap();
 562                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 563                                 if remaining_path.next().is_none() {
 564                                         write!(w, "{}", this_param).unwrap();
 565                                         return;
 566                                 }
 567                         }
 568                         types.write_c_type(w, &*rtype, generics, true);
 569                 },
 570                 _ => {},
 571         }
 572 }
 573
 574 /// Print the main part of a method declaration body, starting with a newline after the function
 575 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 576 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 577 /// parameters we mapped to/from C here.
 578 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) {
 579         let mut num_unused = 0u32;
 580         for inp in sig.inputs.iter() {
 581                 match inp {
 582                         syn::FnArg::Receiver(_) => {},
 583                         syn::FnArg::Typed(arg) => {
 584                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 585                                 if !arg.attrs.is_empty() { unimplemented!(); }
 586                                 macro_rules! write_new_var {
 587                                         ($ident: expr, $ty: expr) => {
 588                                                 if to_c {
 589                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 590                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 591                                                         }
 592                                                 } else {
 593                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 594                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 595                                                         }
 596                                                 }
 597                                         }
 598                                 }
 599                                 match &*arg.pat {
 600                                         syn::Pat::Ident(ident) => {
 601                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 602                                                         unimplemented!();
 603                                                 }
 604                                                 write_new_var!(ident.ident, *arg.ty);
 605                                         },
 606                                         syn::Pat::Wild(w) => {
 607                                                 if !w.attrs.is_empty() { unimplemented!(); }
 608                                                 write_new_var!(format_ident!("unused_{}", num_unused), *arg.ty);
 609                                                 num_unused += 1;
 610                                         },
 611                                         _ => unimplemented!(),
 612                                 }
 613                         }
 614                 }
 615         }
 616         match &sig.output {
 617                 syn::ReturnType::Type(_, _) => {
 618                         write!(w, "let mut ret = ").unwrap();
 619                 },
 620                 _ => {},
 621         }
 622 }
 623
 624 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 625 /// final return statement returning the method's result. Should be followed by a single closing
 626 /// bracket.
 627 ///
 628 /// The return value is expected to be bound to a variable named `ret` which is available after a
 629 /// method-call-ending semicolon.
 630 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) {
 631         let mut first_arg = true;
 632         let mut num_unused = 0;
 633         for inp in sig.inputs.iter() {
 634                 match inp {
 635                         syn::FnArg::Receiver(recv) => {
 636                                 if !recv.attrs.is_empty() { unimplemented!(); }
 637                                 if to_c {
 638                                         if recv.reference.is_none() { unimplemented!(); }
 639                                         write!(w, "self.this_arg").unwrap();
 640                                         first_arg = false;
 641                                 }
 642                         },
 643                         syn::FnArg::Typed(arg) => {
 644                                 if types.skip_arg(&*arg.ty, generics) {
 645                                         if !to_c {
 646                                                 if !first_arg {
 647                                                         write!(w, ", ").unwrap();
 648                                                 }
 649                                                 first_arg = false;
 650                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 651                                         }
 652                                         continue;
 653                                 }
 654                                 if !arg.attrs.is_empty() { unimplemented!(); }
 655                                 macro_rules! write_ident {
 656                                         ($ident: expr) => {
 657                                                 if !first_arg {
 658                                                         write!(w, ", ").unwrap();
 659                                                 }
 660                                                 first_arg = false;
 661                                                 if to_c {
 662                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 663                                                         write!(w, "{}", $ident).unwrap();
 664                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 665                                                 } else {
 666                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 667                                                         write!(w, "{}", $ident).unwrap();
 668                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 669                                                 }
 670                                         }
 671                                 }
 672                                 match &*arg.pat {
 673                                         syn::Pat::Ident(ident) => {
 674                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 675                                                         unimplemented!();
 676                                                 }
 677                                                 write_ident!(ident.ident);
 678                                         },
 679                                         syn::Pat::Wild(w) => {
 680                                                 if !w.attrs.is_empty() { unimplemented!(); }
 681                                                 write_ident!(format!("unused_{}", num_unused));
 682                                                 num_unused += 1;
 683                                         },
 684                                         _ => unimplemented!(),
 685                                 }
 686                         }
 687                 }
 688         }
 689         write!(w, ")").unwrap();
 690         match &sig.output {
 691                 syn::ReturnType::Type(_, rtype) => {
 692                         write!(w, ";\n\t{}", extra_indent).unwrap();
 693
 694                         let self_segs_iter = first_seg_self(&*rtype);
 695                         if to_c && first_seg_self(&*rtype).is_some() {
 696                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 697                                 write!(w, "ret").unwrap();
 698                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 699                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 700                                 write!(w, "{} {{ inner: Box::into_raw(Box::new(ret)), is_owned: true }}", this_type).unwrap();
 701                         } else if to_c {
 702                                 let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("ret"), rtype, generics);
 703                                 if new_var {
 704                                         write!(w, "\n\t{}", extra_indent).unwrap();
 705                                 }
 706                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 707                                 write!(w, "ret").unwrap();
 708                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 709                         } else {
 710                                 let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("ret"), &rtype, generics, true);
 711                                 if new_var {
 712                                         write!(w, "\n\t{}", extra_indent).unwrap();
 713                                 }
 714                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 715                                 write!(w, "ret").unwrap();
 716                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 717                         }
 718                 }
 719                 _ => {},
 720         }
 721 }
 722
 723 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 724 /// greater-than symbols, if any generic parameters are defined.
 725 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 726         let mut gen_types = GenericTypes::new(None);
 727         assert!(gen_types.learn_generics(generics, types));
 728         if !generics.params.is_empty() {
 729                 write!(w, "<").unwrap();
 730                 for (idx, generic) in generics.params.iter().enumerate() {
 731                         match generic {
 732                                 syn::GenericParam::Type(type_param) => {
 733                                         let mut printed_param = false;
 734                                         for bound in type_param.bounds.iter() {
 735                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 736                                                         assert_simple_bound(&trait_bound);
 737                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, gen_types.maybe_resolve_ident(&type_param.ident).unwrap()).unwrap();
 738                                                         if printed_param {
 739                                                                 unimplemented!("Can't print generic params that have multiple non-lifetime bounds");
 740                                                         }
 741                                                         printed_param = true;
 742                                                 }
 743                                         }
 744                                 },
 745                                 syn::GenericParam::Lifetime(lt) => {
 746                                         if concrete_lifetimes {
 747                                                 write!(w, "'static").unwrap();
 748                                         } else {
 749                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 750                                         }
 751                                 },
 752                                 _ => unimplemented!(),
 753                         }
 754                 }
 755                 write!(w, ">").unwrap();
 756         }
 757 }
 758
 759