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//! 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); //! } //! //! # macro_rules! ignore { ($($t:tt)*) => () } ignore! { //! #[::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, env, fs, io, path::Path, }; use_prelude!(); use rust::{String, Vec}; pub use definer::{Definer, HashSetDefiner}; mod definer; macro_rules! with_optional_fields {( $( $(#[$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)? )) } /// 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(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, )* // } // } } )} with_optional_fields! { /// Sets up the name of the `ifndef` guard of the header file. /// /// It defaults to: /// /// ```rust,ignore /// format!("__RUST_{}__", env::var("CARGO_PKG_NAME")?.to_ascii_uppercase()) /// ``` 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, } 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, mut definer: impl Definer) -> io::Result<()> { let s; let config = self; let guard: &'_ str = if let Some(it) = config.guard { it } else { s = format!("__RUST_{}__", env::var("CARGO_PKG_NAME") .unwrap() .to_ascii_uppercase() ); &*s } ; let banner: &'_ str = config.banner.unwrap_or(concat!( "/*! \\file */\n", "/*******************************************\n", " * *\n", " * File auto-generated by `::safer_ffi`. *\n", " * *\n", " * Do not manually edit this file. *\n", " * *\n", " *******************************************/", )); write!(definer.out(), concat!( "{banner}\n\n", "#ifndef {guard}\n", "#define {guard}\n", "\n", "#ifdef __cplusplus\n", "extern \"C\" {{\n", "#endif\n\n", ), guard = guard, banner = banner, )?; crate::inventory::iter .into_iter() // Iterate in reverse fashion to more closely match // the Rust definition order. .collect::<Vec<_>>().into_iter().rev() .try_for_each(|crate::FfiExport(define)| define(&mut definer)) ? ; write!(definer.out(), concat!( "\n", "#ifdef __cplusplus\n", "}} /* extern \"C\" */\n", "#endif\n", "\n", "#endif /* {} */\n", ), guard, )?; Ok(()) } }