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