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#![cfg_attr(rustfmt, rustfmt::skip)]
//! C headers generation.
//!
//! This module is only enabled when the `"headers"` feature of `::safer_ffi` is
//! enabled, which is expected to be done through a cargo feature within the
//! (downstream) crate defining the `#[ffi_export]`ed
//! functions.
//!
//! ```toml
//! [dependencies]
//! safer-ffi = { version = "...", features = ["proc_macros"] }
//!
//! [features]
//! generate-headers = ["safer-ffi/headers"]
//! ```
//!
//! Then, to generate the bindings, just define a
//! `#[safer_ffi::cfg_headers]`-gated `#[test]` function,
//! which can then call the [`builder`] to do the work:
//!
//! ```rust
//! use ::std::{io, fs};
//! use ::safer_ffi::prelude::*;
//!
//! /// Concatenate two strings.
//! ///
//! /// The returned value must be freed with `rust_free`
//! #[ffi_export]
//! fn rust_concat (fst: char_p::Ref<'_>, snd: char_p::Ref<'_>)
//! -> char_p::Box
//! {
//! let s: String = format!("{}{}\0", fst, snd);
//! s .try_into() // Try to convert to a boxed `char *` pointer
//! .unwrap() // Only fails if there is an inner nul byte.
//! }
//!
//! /// Frees a pointer obtained by calling `rust_concat`.
//! #[ffi_export]
//! fn rust_free (it: char_p::Box)
//! {
//! drop(it);
//! }
//!
//! # #[cfg(any())] macro_rules! {
//! #[::safer_ffi::cfg_headers]
//! #[test]
//! # }
//! fn generate_c_header ()
//! -> io::Result<()>
//! {
//! ::safer_ffi::headers::builder()
//! .with_guard("__ASGARD__")
//! .to_file("filename.h")?
//! .generate()
//! }
//! # generate_c_header().unwrap();
//! ```
//!
//! so that
//!
//! ```shell
//! cargo test --features generate-headers -- \
//! --exact generate_c_header \
//! --nocapture
//! ```
//!
//! generates a `"filename.h"` file (⚠️ overwriting it if it exists ⚠️) with
//! the following contents:
//!
//! <pre style="color:#000020;background:#f6f8ff;"><span style="color:#3f7f8f; ">/*! \file */</span>
//! <span style="color:#3f7f8f; ">/*******************************************</span>
//! <span style="color:#3f7f8f; "> * *</span>
//! <span style="color:#3f7f8f; "> * File auto-generated by `::safer_ffi`. *</span>
//! <span style="color:#3f7f8f; "> * *</span>
//! <span style="color:#3f7f8f; "> * Do not manually edit this file. *</span>
//! <span style="color:#3f7f8f; "> * *</span>
//! <span style="color:#3f7f8f; "> *******************************************/</span>
//!
//! <span style="color:#004a43; ">#</span><span style="color:#004a43; ">ifndef</span><span style="color:#004a43; "> __ASGARD__</span>
//! <span style="color:#004a43; ">#</span><span style="color:#004a43; ">define</span><span style="color:#004a43; "> __ASGARD__</span>
//!
//!
//! <span style="color:#3f7f8f; ">/** \brief</span>
//! <span style="color:#3f7f8f; "> * Concatenate two strings.</span>
//! <span style="color:#3f7f8f; "> * </span>
//! <span style="color:#3f7f8f; "> * The returned value must be freed with `rust_free_string`</span>
//! <span style="color:#3f7f8f; "> */</span>
//! <span style="color:#200080; font-weight:bold; ">char</span> <span style="color:#308080; ">*</span> rust_concat <span style="color:#308080; ">(</span>
//! <span style="color:#200080; font-weight:bold; ">char</span> <span style="color:#200080; font-weight:bold; ">const</span> <span style="color:#308080; ">*</span> fst<span style="color:#308080; ">,</span>
//! <span style="color:#200080; font-weight:bold; ">char</span> <span style="color:#200080; font-weight:bold; ">const</span> <span style="color:#308080; ">*</span> snd<span style="color:#308080; ">)</span><span style="color:#406080; ">;</span>
//!
//! <span style="color:#3f7f8f; ">/** \brief</span>
//! <span style="color:#3f7f8f; "> * Frees a pointer obtained by calling `rust_concat`.</span>
//! <span style="color:#3f7f8f; "> */</span>
//! <span style="color:#200080; font-weight:bold; ">void</span> rust_free_string <span style="color:#308080; ">(</span>
//! <span style="color:#200080; font-weight:bold; ">char</span> <span style="color:#308080; ">*</span> it<span style="color:#308080; ">)</span><span style="color:#406080; ">;</span>
//!
//!
//! <span style="color:#004a43; ">#</span><span style="color:#004a43; ">endif</span><span style="color:#004a43; "> </span><span style="color:#595979; ">/* __ASGARD__ */</span>
//! </pre>
#![allow(missing_copy_implementations, missing_debug_implementations)]
use ::std::{
collections::HashSet,
fs,
io,
path::Path,
};
use_prelude!();
use rust::{String};
pub // (in crate)
mod languages;
pub use definer::{Definer, HashSetDefiner};
mod definer;
match_! {(
/// Sets up the name of the `ifndef` guard of the header file.
///
/// It defaults to:
///
/// ```rust,ignore
/// format!("__RUST_{}__", env::var("CARGO_CRATE_NAME")?.replace("-", "_").to_ascii_uppercase())
/// ```
guard: &'__ str,
/// Text included after the include guard of the header file
///
/// It defaults to an empty string
text_after_guard: &'__ str,
/// Sets up the banner of the generated C header file.
///
/// It defaults to:
///
/// ```rust,ignore
/// concat!(
/// "/*! \\file */\n",
/// "/*******************************************\n",
/// " * *\n",
/// " * File auto-generated by `::safer_ffi`. *\n",
/// " * *\n",
/// " * Do not manually edit this file. *\n",
/// " * *\n",
/// " *******************************************/\n",
/// )
/// ```
///
/// <pre style="color:#000020;background:#f6f8ff;"><span style="color:#3f7f8f; ">/*! \file */</span>
/// <span style="color:#3f7f8f; ">/*******************************************</span>
/// <span style="color:#3f7f8f; "> * *</span>
/// <span style="color:#3f7f8f; "> * File auto-generated by `::safer_ffi`. *</span>
/// <span style="color:#3f7f8f; "> * *</span>
/// <span style="color:#3f7f8f; "> * Do not manually edit this file. *</span>
/// <span style="color:#3f7f8f; "> * *</span>
/// <span style="color:#3f7f8f; "> *******************************************/</span>
/// </pre>
banner: &'__ str,
/// Sets the [`Language`] of the generated headers.
///
/// It defaults to [`Language::C`].
language: Language,
/// Sets prefix for generated functions, structs & enums
naming_convention: NamingConvention,
/// Whether to yield a stable header or not (order of defined items guaranteed
/// not to change provided the source code doesn't change either).
///
/// It defaults to `true`.
stable_header: bool,
) /* as */ {(
$(
$(#[$field_meta:meta])*
$field:ident : $field_ty:ty
),* $(,)?
) => (
#[derive(Default)]
pub
struct Builder<'__, W> {
target: W,
$(
$field : Option<$field_ty>,
)*
}
pub
fn builder<'__> ()
-> Builder<'__, WhereTo>
{
Builder::default()
}
use __::WhereTo;
mod __ {
#[derive(Default)]
pub
struct WhereTo;
}
::paste::item! {
impl<'__, W> Builder<'__, W> {
$(
$(#[$field_meta])*
pub
fn [<with_$field>] (self, $field : $field_ty)
-> Self
{
let $field = Some($field);
Self {
$field,
.. self
}
}
)*
}
}
impl<'__> Builder<'__, WhereTo> {
/// Specify the path to the file to be generated.
///
/// **⚠️ If it already exists, its contents will be overwritten ⚠️**
///
/// There is no default value here, either `.to_file()` or [`.to_writer()`]
/// need to be called to be able to [`.generate()`] the headers.
///
/// For more fine-grained control over the "output stream" where the
/// headers will be written to, use [`.to_writer()`].
///
/// # Example
///
/// ```rust,no_run
/// # fn main () -> ::std::io::Result<()> { Ok({
/// ::safer_ffi::headers::builder()
/// .to_file("my_header.h")?
/// .generate()?
/// # })}
/// ```
///
/// [`.to_writer()`]: `Builder::to_writer`
/// [`.generate()`]: `Builder::generate`
pub
fn to_file (
self: Self,
filename: impl AsRef<Path>,
) -> io::Result<Builder<'__, fs::File>>
{
Ok(self.to_writer(
fs::OpenOptions::new()
.create(true)/*or*/.truncate(true)
.write(true)
.open(filename.as_ref())?
))
}
/// Specify the [`Write`][`io::Write`] "stream" where the headers will
/// be written to.
///
/// # Example
///
/// ```rust,no_run
/// // Display the headers to the standard output
/// // (may need the `--nocapture` flag when running the tests)
/// # fn main () -> ::std::io::Result<()> { Ok({
/// ::safer_ffi::headers::builder()
/// .to_writer(::std::io::stdout())
/// .generate()?
/// # })}
/// ```
pub
fn to_writer<W> (
self: Self,
out: W,
) -> Builder<'__, W>
where
W : io::Write
{
let Self {
target: WhereTo, $(
$field, )*
..
} = self;
Builder {
target: out,
$($field ,)*
}
}
}
impl<'__, W : io::Write> Builder<'__, W> {
/// Generate the C header file.
pub
fn generate (self)
-> io::Result<()>
{
let Self { mut target, $($field ,)* } = self;
Builder {
target: WhereTo, $(
$field, )*
}.generate_with_definer(&mut HashSetDefiner {
out: &mut target,
defines_set: Default::default(),
})
}
// pub
// fn as_mut_dyn (self: &'__ mut Self)
// -> Builder<'__, &'__ mut dyn io::Write>
// where
// W : '__,
// {
// let Self { ref mut target, $($field ,)* } = *self;
// Builder {
// target, $(
// $field, )*
// }
// }
}
)}}
impl Builder<'_, WhereTo> {
/// More customizable version of [`.generate()`][Builder::generate].
///
/// With this call, one can provide a custom implementation of a [`Definer`],
/// which can be useful for mock tests, mainly.
pub
fn generate_with_definer (self, definer: &mut impl Definer)
-> io::Result<()>
{
let config = self;
// Banner
config.write_banner(definer)?;
// Prelude
config.write_prelude(definer)?;
/* User-provided defs! */
config.write_body(definer)?;
// Epilogue
config.write_epilogue(definer)?;
Ok(())
}
fn write_banner (&'_ self, definer: &'_ mut dyn Definer)
-> io::Result<()>
{
let banner: &'_ str = self.banner.unwrap_or(concat!(
"/*! \\file */\n",
"/*******************************************\n",
" * *\n",
" * File auto-generated by `::safer_ffi`. *\n",
" * *\n",
" * Do not manually edit this file. *\n",
" * *\n",
" *******************************************/\n",
));
writeln!(definer.out(), "{}", banner)
}
fn write_prelude (&'_ self, definer: &'_ mut dyn Definer)
-> io::Result<()>
{
let lang = self.language.unwrap_or(Language::C);
let guard = self.guard();
let text_after_guard = self.text_after_guard();
match lang {
| Language::C => writeln!(definer.out(),
include_str!("templates/c/_prelude.h"),
guard = guard,
text_after_guard = text_after_guard,
),
| Language::CSharp => writeln!(definer.out(),
include_str!("templates/csharp/_prelude.cs"),
NameSpace = Self::pascal_cased_lib_name(),
RustLib = Self::lib_name(),
),
#[cfg(feature = "python-headers")]
// CHECKME
| Language::Python => Ok(()),
}
}
/// Heart of safer ffi: write the items in the header
fn write_body (&'_ self, definer: &'_ mut dyn Definer)
-> io::Result<()>
{
let stable_header = self.stable_header.unwrap_or(true);
let lang = self.language.unwrap_or(Language::C);
let _naming_convention =
self.naming_convention
.as_ref()
.unwrap_or(&NamingConvention::Default)
;
let (mut storage0, mut storage1) = (None, None);
let gen_defs: &mut dyn Iterator<Item = _> = if stable_header {
storage0.get_or_insert(
crate::inventory::iter
.into_iter()
.map(|crate::FfiExport { name, gen_def }| (name, gen_def))
// Sort the definitions for a reliable header generation.
.collect::<::std::collections::BTreeMap<_, _>>()
.into_iter()
.map(|(_, gen_def)| gen_def)
)
} else {
storage1.get_or_insert(
crate::inventory::iter
.into_iter()
// Iterate in reverse fashion to more closely match
// the Rust definition order.
.collect::<rust::Vec<_>>().into_iter().rev()
.map(|crate::FfiExport { gen_def, .. }| gen_def)
)
};
(&mut { gen_defs }).try_for_each(|gen_def| gen_def(definer, lang))?;
Ok(())
}
fn write_epilogue (&'_ self, definer: &'_ mut dyn Definer)
-> io::Result<()>
{
let lang = self.language.unwrap_or(Language::C);
match lang {
| Language::C => write!(definer.out(),
include_str!("templates/c/epilogue.h"),
guard = self.guard(),
),
| Language::CSharp => {
let pkg_name = Self::pascal_cased_lib_name();
write!(definer.out(),
include_str!("templates/csharp/epilogue.cs"),
PkgName = pkg_name,
)
},
#[cfg(feature = "python-headers")]
// CHECKME
| Language::Python => Ok(()),
}
}
fn guard (&'_ self)
-> String
{
self.guard.map_or_else(
|| format!("__RUST_{}__", Self::lib_name().to_ascii_uppercase()),
Into::into,
)
}
fn text_after_guard(&'_ self)
-> String
{
match self.text_after_guard {
None => String::new(),
Some(s) => format!("\n\n{}\n", s)
}
}
/// Return the library name
fn lib_name ()
-> String
{
::std::env::var("CARGO_CRATE_NAME")
.or_else(|_| {
::std::env::var("CARGO_PKG_NAME")
.map(|s| s.replace('-', "_"))
})
.expect("Missing `CARGO_{CRATE,PKG}_NAME` env vars")
}
/// Return a Pascal Cased (UpperCamelCase) version of the lib name.
fn pascal_cased_lib_name() -> String {
Self::lib_name()
.chars()
.filter_map({
// `true` for PascalCase, `false` for lowerCamelCase.
let mut underscore = true;
move |c| Some(match c {
| _ if underscore => {
underscore = false;
c.to_ascii_uppercase()
},
| '_' => {
underscore = true;
return None; // continue
},
| _ => {
c
},
})
})
.collect::<String>()
}
}
/// Language of the generated headers.
#[derive(
Debug,
Copy, Clone,
PartialEq, Eq,
)]
pub
enum Language {
/// C, _lingua franca_ of FFI interop.
C,
/// C#
CSharp,
/// Python (experimental).
#[cfg(feature = "python-headers")]
Python,
}
/// Allow user to specify
pub
enum NamingConvention {
Default,
Suffix(String),
Prefix(String),
Custom(fn(&str)-> String),
}
hidden_export! {
/// Invoke the language-specific typedef code for the given type.
fn __define_self__<T : ReprC> (
definer: &'_ mut dyn Definer,
lang: Language,
) -> ::std::io::Result<()>
{
match lang {
| Language::C => {
<T::CLayout as CType>::define_self(&crate::headers::languages::C, definer)
},
| Language::CSharp => {
<T::CLayout as CType>::define_self(&crate::headers::languages::CSharp, definer)
},
#[cfg(feature = "python-headers")]
| Language::Python => {
<T::CLayout as CType>::define_self(&crate::headers::languages::Python, definer)
},
}
}
}
use self::languages::{
FunctionArg,
HeaderLanguage,
PhantomCType,
};
#[apply(hidden_export)]
fn __define_fn__ (
definer: &'_ mut dyn Definer,
lang: Language,
docs: &'_ [&'_ str],
fname: &'_ str,
args: &'_ [FunctionArg<'_>],
ret_ty: &'_ dyn PhantomCType,
) -> io::Result<()>
{
let dyn_lang: &dyn HeaderLanguage = match lang {
| Language::C => &languages::C,
| Language::CSharp => &languages::CSharp,
#[cfg(feature = "python-headers")]
| Language::Python => &languages::Python,
};
dyn_lang.emit_function(
definer,
docs,
fname,
args,
ret_ty,
)
}
hidden_export! {
/// Helpers for the generation of FFI-imported function declarations.
mod __define_fn__ {
use super::*;
use ::std::{
fmt::Write as _,
io::Result,
};
pub
fn name (
out: &'_ mut String,
f_name: &'_ str,
lang: Language,
)
{
match lang {
| Language::C => write!(out,
"{} (", f_name.trim(),
),
| Language::CSharp => write!(out,
"{} (", f_name.trim(),
),
#[cfg(feature = "python-headers")]
| Language::Python => write!(out,
"{} (", f_name.trim(),
),
}
.expect("`write!`-ing to a `String` cannot fail")
}
pub
fn arg<Arg : ReprC> (
out: &'_ mut String,
arg_name: &'_ str,
lang: Language,
)
{
if out.ends_with("(").not() {
out.push_str(",");
}
match lang {
| Language::C => write!(out,
"\n {}",
Arg::CLayout::name_wrapping_var(&crate::headers::languages::C, arg_name),
),
| Language::CSharp => write!(out,
"\n {marshaler}{}",
Arg::CLayout::name_wrapping_var(&crate::headers::languages::CSharp, arg_name),
marshaler =
Arg::CLayout::csharp_marshaler()
.map(|m| format!("[MarshalAs({})]\n ", m))
.as_deref()
.unwrap_or("")
,
),
#[cfg(feature = "python-headers")]
| Language::Python => write!(out,
"\n {}",
Arg::CLayout::name_wrapping_var(&crate::headers::languages::Python, arg_name),
),
}
.expect("`write!`-ing to a `String` cannot fail")
}
pub
fn ret<Ret : ReprC> (
definer: &'_ mut dyn Definer,
lang: Language,
mut fname_and_args: String,
) -> Result<()>
{
let out = definer.out();
match lang {
| Language::C => {
if fname_and_args.ends_with("(") {
fname_and_args.push_str("void");
}
writeln!(out,
"{});\n",
Ret::CLayout::name_wrapping_var(&crate::headers::languages::C, &fname_and_args),
)
},
| Language::CSharp => {
writeln!(out,
concat!(
"public unsafe partial class Ffi {{\n ",
"{mb_marshaler}",
"[DllImport(RustLib, ExactSpelling = true)] public static unsafe extern\n",
" {});\n",
"}}\n",
),
Ret::CLayout::name_wrapping_var(&crate::headers::languages::CSharp, &fname_and_args),
mb_marshaler =
Ret::CLayout::csharp_marshaler()
.map(|m| format!("[return: MarshalAs({})]\n ", m))
.as_deref()
.unwrap_or("")
,
)
},
#[cfg(feature = "python-headers")]
| Language::Python => {
if fname_and_args.ends_with("(") {
fname_and_args.push_str("void");
}
writeln!(out,
"{});\n",
Ret::CLayout::name_wrapping_var(&crate::headers::languages::Python, &fname_and_args),
)
},
}
}
}
}