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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")?.replace("-", "_").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()
.replace("-", "_")
.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(())
}
}