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|
extern crate syn;
use syn::export::ToTokens;
extern crate proc_macro2;
const PREFIX: &'static str = "pgp_";
/// Derives the C type from the Rust type.
///
/// Returns the corresponding C type, and whether or not that type is
/// a pointer type.
fn ident2c(ident: &syn::Ident) -> (String, bool) {
let ident_string = ident.to_string();
// Special cases :(
match ident_string.as_str() {
"KeyID" => return ("pgp_keyid_t".into(), true),
"CertBuilder" => return ("pgp_cert_builder_t".into(), true),
"UserID" => return ("pgp_userid_t".into(), true),
"UserIDBundle" => return ("pgp_user_id_bundle_t".into(), true),
"UserIDBundleIter" =>
return ("pgp_user_id_bundle_iter_t".into(), true),
// Types from the libc crate.
"c_void" => return ("void".into(), false),
"c_char" => return ("char".into(), false),
"c_int" => return ("int".into(), false),
"c_uint" => return ("uint".into(), false),
"bool" => return ("bool".into(), false),
"size_t" | "ssize_t" | "time_t" |
"int8_t" | "int16_t" | "int32_t" | "int64_t" |
"uint8_t" | "uint16_t" | "uint32_t" | "uint64_t"
=> return (ident_string.clone(), false),
// Primitive types.
"u8" => return ("uint8_t".into(), false),
"u16" => return ("uint16_t".into(), false),
"u32" => return ("uint32_t".into(), false),
"u64" => return ("uint64_t".into(), false),
"i8" => return ("int8_t".into(), false),
"i16" => return ("int16_t".into(), false),
"i32" => return ("int32_t".into(), false),
"i64" => return ("int64_t".into(), false),
_ => (),
}
let mut s = String::new();
s += PREFIX;
let mut last_was_uppercase = false;
for (i, c) in ident_string.chars().enumerate() {
if c.is_uppercase() {
if ! last_was_uppercase && i > 0 {
s += "_";
}
s += &c.to_lowercase().to_string();
} else {
s += &c.to_string();
}
last_was_uppercase = c.is_uppercase();
}
s += "_t";
(s, true)
}
fn type2c<T: ToTokens>(typ: T) -> String {
let mut tokens = proc_macro2::TokenStream::new();
typ.to_tokens(&mut tokens);
let mut c_typ = String::new();
let mut is_mutable = false;
let mut is_pointer = 0;
let mut ident = None;
for tok in tokens {
use proc_macro2::TokenTree::*;
if false {
eprintln!("mut: {}, ptr: {}, ident: {:?}, tok: {:?}",
is_mutable, is_pointer, ident, tok);
}
match tok {
Ident(ref i) => {
let i_ = format!("{}", i);
match i_.as_str() {
"mut" => is_mutable = true,
"const" => is_mutable = false,
"Option" => (),
"Maybe" => {
is_pointer += 1;
is_mutable = true;
}
_ => {
if is_pointer > 0 && ! is_mutable {
c_typ += "const ";
}
ident = Some(i.clone());
},
}
},
Punct(ref p) => {
if ident.is_some() && p.as_char() != ':' {
// We already found the ident, now skip the <...>.
break;
}
match p.as_char() {
'*' | '&' => {
is_pointer += 1;
},
_ => (),
}
//eprintln!("{:?}", p);
},
Literal(ref l) => panic!("Unexpected {:?}", l),
Group(ref g) => panic!("Unexpected {:?}", g),
}
}
if let Some(c_ident) = ident {
let (c_ident, is_pointer_type) = ident2c(&c_ident);
if is_pointer_type {
is_pointer -= 1;
}
c_typ += &c_ident;
} else {
panic!();
}
c_typ.push(' ');
while is_pointer > 0 {
c_typ.push('*');
is_pointer -= 1;
}
//eprintln!("==> {:?} // {}", c_typ, is_pointer);
c_typ
}
pub fn rust2c(fun: &syn::ItemFn) -> String {
let return_type = match &fun.sig.output {
syn::ReturnType::Default => "void".into(),
syn::ReturnType::Type(_, ref typ) => type2c(typ).trim_end().to_string(),
};
let fun_ident = format!("{}", fun.sig.ident);
let mut s = String::new();
s += &format!("{}\n{} (", return_type, fun_ident);
let indent = fun_ident.len() + 2;
for (i, arg) in fun.sig.inputs.iter().enumerate() {
// All but the first line need to be indented.
if i > 0 {
for _ in 0..indent {
s.push(' ');
}
}
match arg {
&syn::FnArg::Typed(ref cap) => {
let pat_ident = match *cap.pat {
syn::Pat::Ident(ref i) => i,
_ => unimplemented!(),
};
s += &format!("{}{}", type2c(&cap.ty), pat_ident.ident);
},
_ => (),
}
// All but the last one need a comma.
if i < fun.sig.inputs.len() - 1 {
s += ",\n";
}
}
s += ");";
s
}
|
