_ 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, "/// Checks if the given object is currently in the success state").unwrap();
 128         writeln!(w, "#[no_mangle]").unwrap();
 129         writeln!(w, "pub extern \"C\" fn {}_is_ok(o: &{}) -> bool {{", mangled_container, mangled_container).unwrap();
 130         writeln!(w, "\to.result_ok").unwrap();
 131         writeln!(w, "}}").unwrap();
 132
 133         writeln!(w, "#[no_mangle]").unwrap();
 134         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 135         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 136         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 137         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 138         writeln!(w, "\t\tif self.result_ok {{").unwrap();
 139         if ok_type != "()" {
 140                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.result as *mut ()).is_null() }} {{").unwrap();
 141                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.result) }};").unwrap();
 142                 writeln!(w, "\t\t\t}}").unwrap();
 143         }
 144         writeln!(w, "\t\t}} else {{").unwrap();
 145         if err_type != "()" {
 146                 writeln!(w, "\t\t\tif unsafe {{ !(self.contents.err as *mut ()).is_null() }} {{").unwrap();
 147                 writeln!(w, "\t\t\t\tlet _ = unsafe {{ Box::from_raw(self.contents.err) }};").unwrap();
 148                 writeln!(w, "\t\t\t}}").unwrap();
 149         }
 150         writeln!(w, "\t\t}}").unwrap();
 151         writeln!(w, "\t}}").unwrap();
 152         writeln!(w, "}}").unwrap();
 153
 154         writeln!(w, "impl From<crate::c_types::CResultTempl<{}, {}>> for {} {{", ok_type, err_type, mangled_container).unwrap();
 155         writeln!(w, "\tfn from(mut o: crate::c_types::CResultTempl<{}, {}>) -> Self {{", ok_type, err_type).unwrap();
 156         writeln!(w, "\t\tlet contents = if o.result_ok {{").unwrap();
 157         if ok_type != "()" {
 158                 writeln!(w, "\t\t\tlet result = unsafe {{ o.contents.result }};").unwrap();
 159                 writeln!(w, "\t\t\tunsafe {{ o.contents.result = std::ptr::null_mut() }};").unwrap();
 160                 writeln!(w, "\t\t\t{}Ptr {{ result }}", mangled_container).unwrap();
 161         } else {
 162                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.result) }};").unwrap();
 163                 writeln!(w, "\t\t\to.contents.result = std::ptr::null_mut();").unwrap();
 164                 writeln!(w, "\t\t\t{}Ptr {{ result: std::ptr::null_mut() }}", mangled_container).unwrap();
 165         }
 166         writeln!(w, "\t\t}} else {{").unwrap();
 167         if err_type != "()" {
 168                 writeln!(w, "\t\t\tlet err = unsafe {{ o.contents.err }};").unwrap();
 169                 writeln!(w, "\t\t\tunsafe {{ o.contents.err = std::ptr::null_mut(); }}").unwrap();
 170                 writeln!(w, "\t\t\t{}Ptr {{ err }}", mangled_container).unwrap();
 171         } else {
 172                 writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(o.contents.err) }};").unwrap();
 173                 writeln!(w, "\t\t\to.contents.err = std::ptr::null_mut();").unwrap();
 174                 writeln!(w, "\t\t\t{}Ptr {{ err: std::ptr::null_mut() }}", mangled_container).unwrap();
 175         }
 176         writeln!(w, "\t\t}};").unwrap();
 177         writeln!(w, "\t\tSelf {{").unwrap();
 178         writeln!(w, "\t\t\tcontents,").unwrap();
 179         writeln!(w, "\t\t\tresult_ok: o.result_ok,").unwrap();
 180         writeln!(w, "\t\t}}").unwrap();
 181         writeln!(w, "\t}}").unwrap();
 182         writeln!(w, "}}").unwrap();
 183
 184         if clonable {
 185                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 186                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 187                 writeln!(w, "\t\tif self.result_ok {{").unwrap();
 188                 writeln!(w, "\t\t\tSelf {{ result_ok: true, contents: {}Ptr {{", mangled_container).unwrap();
 189                 if ok_type != "()" {
 190                         writeln!(w, "\t\t\t\tresult: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.result }})))", ok_type).unwrap();
 191                 } else {
 192                         writeln!(w, "\t\t\t\tresult: std::ptr::null_mut()").unwrap();
 193                 }
 194                 writeln!(w, "\t\t\t}} }}").unwrap();
 195                 writeln!(w, "\t\t}} else {{").unwrap();
 196                 writeln!(w, "\t\t\tSelf {{ result_ok: false, contents: {}Ptr {{", mangled_container).unwrap();
 197                 if err_type != "()" {
 198                         writeln!(w, "\t\t\t\terr: Box::into_raw(Box::new(<{}>::clone(unsafe {{ &*self.contents.err }})))", err_type).unwrap();
 199                 } else {
 200                         writeln!(w, "\t\t\t\terr: std::ptr::null_mut()").unwrap();
 201                 }
 202                 writeln!(w, "\t\t\t}} }}").unwrap();
 203                 writeln!(w, "\t\t}}").unwrap();
 204                 writeln!(w, "\t}}").unwrap();
 205                 writeln!(w, "}}").unwrap();
 206                 writeln!(w, "#[no_mangle]").unwrap();
 207                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 208                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 209                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
 210         }
 211 }
 212
 213 /// Writes out a C-callable concrete Vec<A> struct and utility methods
 214 pub fn write_vec_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 215         writeln!(w, "#[repr(C)]").unwrap();
 216         writeln!(w, "/// A dynamically-allocated array of {}s of arbitrary size.", inner_type).unwrap();
 217         writeln!(w, "/// This corresponds to std::vector in C++").unwrap();
 218         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 219         writeln!(w, "\t/// The elements in the array.").unwrap();
 220         writeln!(w, "\t/// If datalen is non-0 this must be a valid, non-NULL pointer allocated by malloc().").unwrap();
 221         writeln!(w, "\tpub data: *mut {},", inner_type).unwrap();
 222         writeln!(w, "\t/// The number of elements pointed to by `data`.").unwrap();
 223         writeln!(w, "\tpub datalen: usize").unwrap();
 224         writeln!(w, "}}").unwrap();
 225
 226         writeln!(w, "impl {} {{", mangled_container).unwrap();
 227         writeln!(w, "\t#[allow(unused)] pub(crate) fn into_rust(&mut self) -> Vec<{}> {{", inner_type).unwrap();
 228         writeln!(w, "\t\tif self.datalen == 0 {{ return Vec::new(); }}").unwrap();
 229         writeln!(w, "\t\tlet ret = unsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }}.into();").unwrap();
 230         writeln!(w, "\t\tself.data = std::ptr::null_mut();").unwrap();
 231         writeln!(w, "\t\tself.datalen = 0;").unwrap();
 232         writeln!(w, "\t\tret").unwrap();
 233         writeln!(w, "\t}}").unwrap();
 234         writeln!(w, "\t#[allow(unused)] pub(crate) fn as_slice(&self) -> &[{}] {{", inner_type).unwrap();
 235         writeln!(w, "\t\tunsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }}").unwrap();
 236         writeln!(w, "\t}}").unwrap();
 237         writeln!(w, "}}").unwrap();
 238
 239         writeln!(w, "impl From<Vec<{}>> for {} {{", inner_type, mangled_container).unwrap();
 240         writeln!(w, "\tfn from(v: Vec<{}>) -> Self {{", inner_type).unwrap();
 241         writeln!(w, "\t\tlet datalen = v.len();").unwrap();
 242         writeln!(w, "\t\tlet data = Box::into_raw(v.into_boxed_slice());").unwrap();
 243         writeln!(w, "\t\tSelf {{ datalen, data: unsafe {{ (*data).as_mut_ptr() }} }}").unwrap();
 244         writeln!(w, "\t}}").unwrap();
 245         writeln!(w, "}}").unwrap();
 246
 247         writeln!(w, "#[no_mangle]").unwrap();
 248         writeln!(w, "/// Frees the buffer pointed to by `data` if `datalen` is non-0.").unwrap();
 249         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 250         writeln!(w, "impl Drop for {} {{", mangled_container).unwrap();
 251         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 252         writeln!(w, "\t\tif self.datalen == 0 {{ return; }}").unwrap();
 253         writeln!(w, "\t\tunsafe {{ Box::from_raw(std::slice::from_raw_parts_mut(self.data, self.datalen)) }};").unwrap();
 254         writeln!(w, "\t}}").unwrap();
 255         writeln!(w, "}}").unwrap();
 256         if clonable {
 257                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 258                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 259                 writeln!(w, "\t\tlet mut res = Vec::new();").unwrap();
 260                 writeln!(w, "\t\tif self.datalen == 0 {{ return Self::from(res); }}").unwrap();
 261                 writeln!(w, "\t\tres.extend_from_slice(unsafe {{ std::slice::from_raw_parts_mut(self.data, self.datalen) }});").unwrap();
 262                 writeln!(w, "\t\tSelf::from(res)").unwrap();
 263                 writeln!(w, "\t}}").unwrap();
 264                 writeln!(w, "}}").unwrap();
 265         }
 266 }
 267
 268 /// Writes out a C-callable concrete (A, B, ...) struct and utility methods
 269 pub fn write_tuple_block<W: std::io::Write>(w: &mut W, mangled_container: &str, types: &[String], clonable: bool) {
 270         writeln!(w, "#[repr(C)]").unwrap();
 271         writeln!(w, "/// A tuple of {} elements. See the individual fields for the types contained.", types.len()).unwrap();
 272         writeln!(w, "pub struct {} {{", mangled_container).unwrap();
 273         for (idx, ty) in types.iter().enumerate() {
 274                 writeln!(w, "\t/// The element at position {}", idx).unwrap();
 275                 writeln!(w, "\tpub {}: {},", ('a' as u8 + idx as u8) as char, ty).unwrap();
 276         }
 277         writeln!(w, "}}").unwrap();
 278
 279         let mut tuple_str = "(".to_owned();
 280         for (idx, ty) in types.iter().enumerate() {
 281                 if idx != 0 { tuple_str += ", "; }
 282                 tuple_str += ty;
 283         }
 284         tuple_str += ")";
 285
 286         writeln!(w, "impl From<{}> for {} {{", tuple_str, mangled_container).unwrap();
 287         writeln!(w, "\tfn from (tup: {}) -> Self {{", tuple_str).unwrap();
 288         writeln!(w, "\t\tSelf {{").unwrap();
 289         for idx in 0..types.len() {
 290                 writeln!(w, "\t\t\t{}: tup.{},", ('a' as u8 + idx as u8) as char, idx).unwrap();
 291         }
 292         writeln!(w, "\t\t}}").unwrap();
 293         writeln!(w, "\t}}").unwrap();
 294         writeln!(w, "}}").unwrap();
 295         writeln!(w, "impl {} {{", mangled_container).unwrap();
 296         writeln!(w, "\t#[allow(unused)] pub(crate) fn to_rust(mut self) -> {} {{", tuple_str).unwrap();
 297         write!(w, "\t\t(").unwrap();
 298         for idx in 0..types.len() {
 299                 write!(w, "{}self.{}", if idx != 0 {", "} else {""}, ('a' as u8 + idx as u8) as char).unwrap();
 300         }
 301         writeln!(w, ")").unwrap();
 302         writeln!(w, "\t}}").unwrap();
 303         writeln!(w, "}}").unwrap();
 304
 305         if clonable {
 306                 writeln!(w, "impl Clone for {} {{", mangled_container).unwrap();
 307                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 308                 writeln!(w, "\t\tSelf {{").unwrap();
 309                 for idx in 0..types.len() {
 310                         writeln!(w, "\t\t\t{}: Clone::clone(&self.{}),", ('a' as u8 + idx as u8) as char, ('a' as u8 + idx as u8) as char).unwrap();
 311                 }
 312                 writeln!(w, "\t\t}}").unwrap();
 313                 writeln!(w, "\t}}").unwrap();
 314                 writeln!(w, "}}").unwrap();
 315                 writeln!(w, "#[no_mangle]").unwrap();
 316                 writeln!(w, "/// Creates a new tuple which has the same data as `orig`").unwrap();
 317                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 318                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
 319         }
 320
 321         writeln!(w, "/// Creates a new {} from the contained elements.", mangled_container).unwrap();
 322         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
 323         for (idx, gen) in types.iter().enumerate() {
 324                 write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
 325                 //if !self.write_c_type_intern(&mut created_container, gen, generics, false, false, false) { return false; }
 326                 write!(w, "{}", gen).unwrap();
 327         }
 328         writeln!(w, ") -> {} {{", mangled_container).unwrap();
 329         write!(w, "\t{} {{ ", mangled_container).unwrap();
 330         for idx in 0..types.len() {
 331                 write!(w, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
 332         }
 333         writeln!(w, "}}\n}}\n").unwrap();
 334
 335         writeln!(w, "#[no_mangle]").unwrap();
 336         writeln!(w, "/// Frees any resources used by the {}.", mangled_container).unwrap();
 337         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 338 }
 339
 340 /// Writes out a C-callable concrete Option<A> struct and utility methods
 341 pub fn write_option_block<W: std::io::Write>(w: &mut W, mangled_container: &str, inner_type: &str, clonable: bool) {
 342         writeln!(w, "#[repr(C)]").unwrap();
 343         if clonable {
 344                 writeln!(w, "#[derive(Clone)]").unwrap();
 345         }
 346         writeln!(w, "/// An enum which can either contain a {} or not", inner_type).unwrap();
 347         writeln!(w, "pub enum {} {{", mangled_container).unwrap();
 348         writeln!(w, "\t/// When we're in this state, this {} contains a {}", mangled_container, inner_type).unwrap();
 349         if inner_type != "" {
 350                 writeln!(w, "\tSome({}),", inner_type).unwrap();
 351         } else {
 352                 writeln!(w, "\tSome,").unwrap();
 353         }
 354         writeln!(w, "\t/// When we're in this state, this {} contains nothing", mangled_container).unwrap();
 355         writeln!(w, "\tNone").unwrap();
 356         writeln!(w, "}}").unwrap();
 357
 358         writeln!(w, "impl {} {{", mangled_container).unwrap();
 359         writeln!(w, "\t#[allow(unused)] pub(crate) fn is_some(&self) -> bool {{").unwrap();
 360         writeln!(w, "\t\tif let Self::None = self {{ false }} else {{ true }}").unwrap();
 361         writeln!(w, "\t}}").unwrap();
 362         writeln!(w, "\t#[allow(unused)] pub(crate) fn is_none(&self) -> bool {{").unwrap();
 363         writeln!(w, "\t\t!self.is_some()").unwrap();
 364         writeln!(w, "\t}}").unwrap();
 365         if inner_type != "" {
 366                 writeln!(w, "\t#[allow(unused)] pub(crate) fn take(mut self) -> {} {{", inner_type).unwrap();
 367                 writeln!(w, "\t\tif let Self::Some(v) = self {{ v }} else {{ unreachable!() }}").unwrap();
 368                 writeln!(w, "\t}}").unwrap();
 369         }
 370         writeln!(w, "}}").unwrap();
 371
 372         writeln!(w, "#[no_mangle]").unwrap();
 373         writeln!(w, "/// Constructs a new {} containing a {}", mangled_container, inner_type).unwrap();
 374         if inner_type != "" {
 375                 writeln!(w, "pub extern \"C\" fn {}_some(o: {}) -> {} {{", mangled_container, inner_type, mangled_container).unwrap();
 376                 writeln!(w, "\t{}::Some(o)", mangled_container).unwrap();
 377         } else {
 378                 writeln!(w, "pub extern \"C\" fn {}_some() -> {} {{", mangled_container, mangled_container).unwrap();
 379                 writeln!(w, "\t{}::Some", mangled_container).unwrap();
 380         }
 381         writeln!(w, "}}").unwrap();
 382
 383         writeln!(w, "#[no_mangle]").unwrap();
 384         writeln!(w, "/// Constructs a new {} containing nothing", mangled_container).unwrap();
 385         writeln!(w, "pub extern \"C\" fn {}_none() -> {} {{", mangled_container, mangled_container).unwrap();
 386         writeln!(w, "\t{}::None", mangled_container).unwrap();
 387         writeln!(w, "}}").unwrap();
 388
 389         writeln!(w, "#[no_mangle]").unwrap();
 390         writeln!(w, "/// Frees any resources associated with the {}, if we are in the Some state", inner_type).unwrap();
 391         writeln!(w, "pub extern \"C\" fn {}_free(_res: {}) {{ }}", mangled_container, mangled_container).unwrap();
 392         if clonable {
 393                 writeln!(w, "#[no_mangle]").unwrap();
 394                 writeln!(w, "/// Creates a new {} which has the same data as `orig`", mangled_container).unwrap();
 395                 writeln!(w, "/// but with all dynamically-allocated buffers duplicated in new buffers.").unwrap();
 396                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{ Clone::clone(&orig) }}", mangled_container, mangled_container, mangled_container).unwrap();
 397         }
 398 }
 399
 400 /// Prints the docs from a given attribute list unless its tagged no export
 401 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> {
 402         writeln_docs_impl(w, attrs, prefix, Some((types, generics,
 403                 args.filter_map(|arg| if let syn::FnArg::Typed(ty) = arg {
 404                                 if let syn::Pat::Ident(id) = &*ty.pat {
 405                                         Some((id.ident.to_string(), &*ty.ty))
 406                                 } else { unimplemented!() }
 407                         } else { None }),
 408                 if let syn::ReturnType::Type(_, ty) = ret { Some(&**ty) } else { None },
 409                 None
 410         )));
 411 }
 412
 413 /// Prints the docs from a given attribute list unless its tagged no export
 414 pub fn writeln_docs<W: std::io::Write>(w: &mut W, attrs: &[syn::Attribute], prefix: &str) {
 415         writeln_docs_impl(w, attrs, prefix, None::<(_, _, std::vec::Drain<'_, (String, &syn::Type)>, _, _)>);
 416 }
 417
 418 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)> {
 419         writeln_docs_impl(w, attrs, prefix, Some((types, generics, args, ret, None)))
 420 }
 421
 422 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) {
 423         writeln_docs_impl(w, attrs, prefix, Some((types, generics, vec![].drain(..), None, Some(field))))
 424 }
 425
 426 /// Prints the docs from a given attribute list unless its tagged no export
 427 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)> {
 428         for attr in attrs.iter() {
 429                 let tokens_clone = attr.tokens.clone();
 430                 let mut token_iter = tokens_clone.into_iter();
 431                 if let Some(token) = token_iter.next() {
 432                         match token {
 433                                 TokenTree::Punct(c) if c.as_char() == '=' => {
 434                                         // syn gets '=' from '///' or '//!' as it is syntax for #[doc = ""]
 435                                 },
 436                                 TokenTree::Group(_) => continue, // eg #[derive()]
 437                                 _ => unimplemented!(),
 438                         }
 439                 } else { continue; }
 440                 match attr.style {
 441                         syn::AttrStyle::Inner(_) => {
 442                                 match token_iter.next().unwrap() {
 443                                         TokenTree::Literal(lit) => {
 444                                                 // Drop the first and last chars from lit as they are always "
 445                                                 let doc = format!("{}", lit);
 446                                                 writeln!(w, "{}//!{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 447                                         },
 448                                         _ => unimplemented!(),
 449                                 }
 450                         },
 451                         syn::AttrStyle::Outer => {
 452                                 match token_iter.next().unwrap() {
 453                                         TokenTree::Literal(lit) => {
 454                                                 // Drop the first and last chars from lit as they are always "
 455                                                 let doc = format!("{}", lit);
 456                                                 writeln!(w, "{}///{}", prefix, &doc[1..doc.len() - 1]).unwrap();
 457                                         },
 458                                         _ => unimplemented!(),
 459                                 }
 460                         },
 461                 }
 462         }
 463         if let Some((types, generics, inp, outp, field)) = method_args_ret {
 464                 let mut nullable_found = false;
 465                 for (name, inp) in inp {
 466                         if types.skip_arg(inp, generics) { continue; }
 467                         if if let syn::Type::Reference(syn::TypeReference { elem, .. }) = inp {
 468                                 if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 469                                         types.is_path_transparent_container(path, generics, true)
 470                                 } else { false }
 471                         } else if let syn::Type::Path(syn::TypePath { ref path, .. }) = inp {
 472                                 types.is_path_transparent_container(path, generics, true)
 473                         } else { false } {
 474                                 // Note downstream clients match this text exactly so any changes may require
 475                                 // changes in the Java and Swift bindings, at least.
 476                                 if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 477                                 nullable_found = true;
 478                                 writeln!(w, "{}/// Note that {} (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix, name).unwrap();
 479                         }
 480                 }
 481                 if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = outp {
 482                         if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 483                                 types.is_path_transparent_container(path, generics, true)
 484                         } else { false }
 485                 } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = outp {
 486                         types.is_path_transparent_container(path, generics, true)
 487                 } else { false } {
 488                         // Note downstream clients match this text exactly so any changes may require
 489                         // changes in the Java and Swift bindings, at least.
 490                         if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 491                         nullable_found = true;
 492                         writeln!(w, "{}/// Note that the return value (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
 493                 }
 494                 if if let Some(syn::Type::Reference(syn::TypeReference { elem, .. })) = field {
 495                         if let syn::Type::Path(syn::TypePath { ref path, .. }) = &**elem {
 496                                 types.is_path_transparent_container(path, generics, true)
 497                         } else { false }
 498                 } else if let Some(syn::Type::Path(syn::TypePath { ref path, .. })) = field {
 499                         types.is_path_transparent_container(path, generics, true)
 500                 } else { false } {
 501                         // Note downstream clients match this text exactly so any changes may require
 502                         // changes in the Java and Swift bindings, at least.
 503                         if !nullable_found { writeln!(w, "{}///", prefix).unwrap(); }
 504                         writeln!(w, "{}/// Note that this (or a relevant inner pointer) may be NULL or all-0s to represent None", prefix).unwrap();
 505                 }
 506         }
 507
 508 }
 509
 510 /// Print the parameters in a method declaration, starting after the open parenthesis, through and
 511 /// including the closing parenthesis and return value, but not including the open bracket or any
 512 /// trailing semicolons.
 513 ///
 514 /// Usable both for a function definition and declaration.
 515 ///
 516 /// this_param is used when returning Self or accepting a self parameter, and should be the
 517 /// concrete, mapped type.
 518 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) {
 519         if sig.constness.is_some() || sig.asyncness.is_some() || sig.unsafety.is_some() ||
 520                         sig.abi.is_some() || sig.variadic.is_some() {
 521                 unimplemented!();
 522         }
 523         if sig.generics.lt_token.is_some() {
 524                 for generic in sig.generics.params.iter() {
 525                         match generic {
 526                                 syn::GenericParam::Type(_)|syn::GenericParam::Lifetime(_) => {
 527                                         // We ignore these, if they're not on skipped args, we'll blow up
 528                                         // later, and lifetimes we just hope the C client enforces.
 529                                 },
 530                                 _ => unimplemented!(),
 531                         }
 532                 }
 533         }
 534
 535         let mut first_arg = true;
 536         let mut num_unused = 0;
 537         for inp in sig.inputs.iter() {
 538                 match inp {
 539                         syn::FnArg::Receiver(recv) => {
 540                                 if !recv.attrs.is_empty() { unimplemented!(); }
 541                                 write!(w, "{}this_arg: {}{}", if recv.reference.is_none() { "mut " } else { "" },
 542                                         if recv.reference.is_some() {
 543                                                 match (self_ptr, recv.mutability.is_some()) {
 544                                                         (true, true) => "*mut ",
 545                                                         (true, false) => "*const ",
 546                                                         (false, true) => "&mut ",
 547                                                         (false, false) => "&",
 548                                                 }
 549                                         } else { "" }, this_param).unwrap();
 550                                 assert!(first_arg);
 551                                 first_arg = false;
 552                         },
 553                         syn::FnArg::Typed(arg) => {
 554                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 555                                 if !arg.attrs.is_empty() { unimplemented!(); }
 556                                 // First get the c type so that we can check if it ends up being a reference:
 557                                 let mut c_type = Vec::new();
 558                                 types.write_c_type(&mut c_type, &*arg.ty, generics, false);
 559                                 match &*arg.pat {
 560                                         syn::Pat::Ident(ident) => {
 561                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 562                                                         unimplemented!();
 563                                                 }
 564                                                 write!(w, "{}{}{}: ", if first_arg { "" } else { ", " }, if !fn_decl || c_type[0] == '&' as u8 || c_type[0] == '*' as u8 { "" } else { "mut " }, ident.ident).unwrap();
 565                                                 first_arg = false;
 566                                         },
 567                                         syn::Pat::Wild(wild) => {
 568                                                 if !wild.attrs.is_empty() { unimplemented!(); }
 569                                                 write!(w, "{}unused_{}: ", if first_arg { "" } else { ", " }, num_unused).unwrap();
 570                                                 num_unused += 1;
 571                                         },
 572                                         _ => unimplemented!(),
 573                                 }
 574                                 w.write(&c_type).unwrap();
 575                         }
 576                 }
 577         }
 578         write!(w, ")").unwrap();
 579         match &sig.output {
 580                 syn::ReturnType::Type(_, rtype) => {
 581                         write!(w, " -> ").unwrap();
 582                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 583                                 if remaining_path.next().is_none() {
 584                                         write!(w, "{}", this_param).unwrap();
 585                                         return;
 586                                 }
 587                         }
 588                         types.write_c_type(w, &*rtype, generics, true);
 589                 },
 590                 _ => {},
 591         }
 592 }
 593
 594 /// Print the main part of a method declaration body, starting with a newline after the function
 595 /// open bracket and converting each function parameter to or from C-mapped types. Ends with "let
 596 /// mut ret = " assuming the next print will be the unmapped Rust function to call followed by the
 597 /// parameters we mapped to/from C here.
 598 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) {
 599         let mut num_unused = 0u32;
 600         for inp in sig.inputs.iter() {
 601                 match inp {
 602                         syn::FnArg::Receiver(_) => {},
 603                         syn::FnArg::Typed(arg) => {
 604                                 if types.skip_arg(&*arg.ty, generics) { continue; }
 605                                 if !arg.attrs.is_empty() { unimplemented!(); }
 606                                 macro_rules! write_new_var {
 607                                         ($ident: expr, $ty: expr) => {
 608                                                 if to_c {
 609                                                         if types.write_to_c_conversion_new_var(w, &$ident, &$ty, generics, false) {
 610                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 611                                                         }
 612                                                 } else {
 613                                                         if types.write_from_c_conversion_new_var(w, &$ident, &$ty, generics) {
 614                                                                 write!(w, "\n\t{}", extra_indent).unwrap();
 615                                                         }
 616                                                 }
 617                                         }
 618                                 }
 619                                 match &*arg.pat {
 620                                         syn::Pat::Ident(ident) => {
 621                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 622                                                         unimplemented!();
 623                                                 }
 624                                                 write_new_var!(ident.ident, *arg.ty);
 625                                         },
 626                                         syn::Pat::Wild(w) => {
 627                                                 if !w.attrs.is_empty() { unimplemented!(); }
 628                                                 write_new_var!(format_ident!("unused_{}", num_unused), *arg.ty);
 629                                                 num_unused += 1;
 630                                         },
 631                                         _ => unimplemented!(),
 632                                 }
 633                         }
 634                 }
 635         }
 636         match &sig.output {
 637                 syn::ReturnType::Type(_, _) => {
 638                         write!(w, "let mut ret = ").unwrap();
 639                 },
 640                 _ => {},
 641         }
 642 }
 643
 644 /// Prints the parameters in a method call, starting after the open parenthesis and ending with a
 645 /// final return statement returning the method's result. Should be followed by a single closing
 646 /// bracket.
 647 ///
 648 /// The return value is expected to be bound to a variable named `ret` which is available after a
 649 /// method-call-ending semicolon.
 650 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) {
 651         let mut first_arg = true;
 652         let mut num_unused = 0;
 653         for inp in sig.inputs.iter() {
 654                 match inp {
 655                         syn::FnArg::Receiver(recv) => {
 656                                 if !recv.attrs.is_empty() { unimplemented!(); }
 657                                 if to_c {
 658                                         if recv.reference.is_none() { unimplemented!(); }
 659                                         write!(w, "self.this_arg").unwrap();
 660                                         first_arg = false;
 661                                 }
 662                         },
 663                         syn::FnArg::Typed(arg) => {
 664                                 if types.skip_arg(&*arg.ty, generics) {
 665                                         if !to_c {
 666                                                 if !first_arg {
 667                                                         write!(w, ", ").unwrap();
 668                                                 }
 669                                                 first_arg = false;
 670                                                 types.no_arg_to_rust(w, &*arg.ty, generics);
 671                                         }
 672                                         continue;
 673                                 }
 674                                 if !arg.attrs.is_empty() { unimplemented!(); }
 675                                 macro_rules! write_ident {
 676                                         ($ident: expr) => {
 677                                                 if !first_arg {
 678                                                         write!(w, ", ").unwrap();
 679                                                 }
 680                                                 first_arg = false;
 681                                                 if to_c {
 682                                                         types.write_to_c_conversion_inline_prefix(w, &*arg.ty, generics, false);
 683                                                         write!(w, "{}", $ident).unwrap();
 684                                                         types.write_to_c_conversion_inline_suffix(w, &*arg.ty, generics, false);
 685                                                 } else {
 686                                                         types.write_from_c_conversion_prefix(w, &*arg.ty, generics);
 687                                                         write!(w, "{}", $ident).unwrap();
 688                                                         types.write_from_c_conversion_suffix(w, &*arg.ty, generics);
 689                                                 }
 690                                         }
 691                                 }
 692                                 match &*arg.pat {
 693                                         syn::Pat::Ident(ident) => {
 694                                                 if !ident.attrs.is_empty() || ident.subpat.is_some() {
 695                                                         unimplemented!();
 696                                                 }
 697                                                 write_ident!(ident.ident);
 698                                         },
 699                                         syn::Pat::Wild(w) => {
 700                                                 if !w.attrs.is_empty() { unimplemented!(); }
 701                                                 write_ident!(format!("unused_{}", num_unused));
 702                                                 num_unused += 1;
 703                                         },
 704                                         _ => unimplemented!(),
 705                                 }
 706                         }
 707                 }
 708         }
 709         write!(w, ")").unwrap();
 710         match &sig.output {
 711                 syn::ReturnType::Type(_, rtype) => {
 712                         write!(w, ";\n\t{}", extra_indent).unwrap();
 713
 714                         let self_segs_iter = first_seg_self(&*rtype);
 715                         if to_c && first_seg_self(&*rtype).is_some() {
 716                                 // Assume rather blindly that we're returning an associated trait from a C fn call to a Rust trait object.
 717                                 write!(w, "ret").unwrap();
 718                         } else if !to_c && self_segs_iter.is_some() && self_segs_iter.unwrap().next().is_none() {
 719                                 // If we're returning "Self" (and not "Self::X"), just do it manually
 720                                 write!(w, "{} {{ inner: ObjOps::heap_alloc(ret), is_owned: true }}", this_type).unwrap();
 721                         } else if to_c {
 722                                 let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("ret"), rtype, generics);
 723                                 if new_var {
 724                                         write!(w, "\n\t{}", extra_indent).unwrap();
 725                                 }
 726                                 types.write_from_c_conversion_prefix(w, &*rtype, generics);
 727                                 write!(w, "ret").unwrap();
 728                                 types.write_from_c_conversion_suffix(w, &*rtype, generics);
 729                         } else {
 730                                 let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("ret"), &rtype, generics, true);
 731                                 if new_var {
 732                                         write!(w, "\n\t{}", extra_indent).unwrap();
 733                                 }
 734                                 types.write_to_c_conversion_inline_prefix(w, &rtype, generics, true);
 735                                 write!(w, "ret").unwrap();
 736                                 types.write_to_c_conversion_inline_suffix(w, &rtype, generics, true);
 737                         }
 738                 }
 739                 _ => {},
 740         }
 741 }
 742
 743 /// Prints concrete generic parameters for a struct/trait/function, including the less-than and
 744 /// greater-than symbols, if any generic parameters are defined.
 745 pub fn maybe_write_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver, concrete_lifetimes: bool) {
 746         let mut gen_types = GenericTypes::new(None);
 747         assert!(gen_types.learn_generics(generics, types));
 748         if !generics.params.is_empty() {
 749                 write!(w, "<").unwrap();
 750                 for (idx, generic) in generics.params.iter().enumerate() {
 751                         match generic {
 752                                 syn::GenericParam::Type(type_param) => {
 753                                         write!(w, "{}", if idx != 0 { ", " } else { "" }).unwrap();
 754                                         let type_ident = &type_param.ident;
 755                                         types.write_c_type_in_generic_param(w, &syn::parse_quote!(#type_ident), Some(&gen_types), false);
 756                                 },
 757                                 syn::GenericParam::Lifetime(lt) => {
 758                                         if concrete_lifetimes {
 759                                                 write!(w, "'static").unwrap();
 760                                         } else {
 761                                                 write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 762                                         }
 763                                 },
 764                                 _ => unimplemented!(),
 765                         }
 766                 }
 767                 write!(w, ">").unwrap();
 768         }
 769 }
 770
 771 pub fn maybe_write_lifetime_generics<W: std::io::Write>(w: &mut W, generics: &syn::Generics, types: &TypeResolver) {
 772         let mut gen_types = GenericTypes::new(None);
 773         assert!(gen_types.learn_generics(generics, types));
 774         if generics.params.iter().any(|param| if let syn::GenericParam::Lifetime(_) = param { true } else { false }) {
 775                 write!(w, "<").unwrap();
 776                 for (idx, generic) in generics.params.iter().enumerate() {
 777                         match generic {
 778                                 syn::GenericParam::Type(_) => {},
 779                                 syn::GenericParam::Lifetime(lt) => {
 780                                         write!(w, "{}'{}", if idx != 0 { ", " } else { "" }, lt.lifetime.ident).unwrap();
 781                                 },
 782                                 _ => unimplemented!(),
 783                         }
 784                 }
 785                 write!(w, ">").unwrap();
 786         }
 787 }