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/// A macro for defining #[cfg] if-else statements.
///
/// This is similar to the `if/elif` C preprocessor macro by allowing definition
/// of a cascade of `#[cfg]` cases, emitting the implementation which matches
/// first.
///
/// This allows you to conveniently provide a long list #[cfg]'d blocks of code
/// without having to rewrite each clause multiple times.
macro_rules! cfg_if {
// match if/else chains with a final `else`
($(
if #[cfg($($meta:meta),*)] { $($it:item)* }
) else * else {
$($it2:item)*
}) => {
cfg_if! {
@__items
() ;
$( ( ($($meta),*) ($($it)*) ), )*
( () ($($it2)*) ),
}
};
// match if/else chains lacking a final `else`
(
if #[cfg($($i_met:meta),*)] { $($i_it:item)* }
$(
else if #[cfg($($e_met:meta),*)] { $($e_it:item)* }
)*
) => {
cfg_if! {
@__items
() ;
( ($($i_met),*) ($($i_it)*) ),
$( ( ($($e_met),*) ($($e_it)*) ), )*
( () () ),
}
};
// Internal and recursive macro to emit all the items
//
// Collects all the negated `cfg`s in a list at the beginning and after the
// semicolon is all the remaining items
(@__items ($($not:meta,)*) ; ) => {};
(@__items ($($not:meta,)*) ; ( ($($m:meta),*) ($($it:item)*) ),
$($rest:tt)*) => {
// Emit all items within one block, applying an appropriate #[cfg]. The
// #[cfg] will require all `$m` matchers specified and must also negate
// all previous matchers.
cfg_if! { @__apply cfg(all($($m,)* not(any($($not),*)))), $($it)* }
// Recurse to emit all other items in `$rest`, and when we do so add all
// our `$m` matchers to the list of `$not` matchers as future emissions
// will have to negate everything we just matched as well.
cfg_if! { @__items ($($not,)* $($m,)*) ; $($rest)* }
};
// Internal macro to Apply a cfg attribute to a list of items
(@__apply $m:meta, $($it:item)*) => {
$(#[$m] $it)*
};
}
/// Create an internal crate prelude with `core` reexports and common types.
macro_rules! prelude {
() => {
/// Frequently-used types that are available on all platforms
///
/// We need to reexport the core types so this works with `rust-dep-of-std`.
mod prelude {
// Exports from `core`
#[allow(unused_imports)]
pub(crate) use ::core::clone::Clone;
#[allow(unused_imports)]
pub(crate) use ::core::marker::{Copy, Send, Sync};
#[allow(unused_imports)]
pub(crate) use ::core::option::Option;
#[allow(unused_imports)]
pub(crate) use ::core::{fmt, hash, iter, mem};
// Commonly used types defined in this crate
#[allow(unused_imports)]
pub(crate) use crate::{
c_char, c_double, c_float, c_int, c_long, c_longlong, c_short, c_uchar, c_uint,
c_ulong, c_ulonglong, c_ushort, c_void, intptr_t, size_t, ssize_t, uintptr_t,
};
}
};
}
/// Implement `Clone` and `Copy` for a struct, as well as `Debug`, `Eq`, `Hash`, and
/// `PartialEq` if the `extra_traits` feature is enabled.
///
/// Use [`s_no_extra_traits`] for structs where the `extra_traits` feature does not
/// make sense, and for unions.
macro_rules! s {
($(
$(#[$attr:meta])*
pub $t:ident $i:ident { $($field:tt)* }
)*) => ($(
s!(it: $(#[$attr])* pub $t $i { $($field)* });
)*);
(it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
compile_error!("unions cannot derive extra traits, use s_no_extra_traits instead");
);
(it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[cfg_attr(
feature = "extra_traits",
::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
#[allow(deprecated)]
$(#[$attr])*
pub struct $i { $($field)* }
}
);
}
/// Implement `Clone` and `Copy` for a tuple struct, as well as `Debug`, `Eq`, `Hash`,
/// and `PartialEq` if the `extra_traits` feature is enabled.
///
/// This is the same as [`s`] but works for tuple structs.
macro_rules! s_paren {
($(
$(#[$attr:meta])*
pub struct $i:ident ( $($field:tt)* );
)*) => ($(
__item! {
#[cfg_attr(
feature = "extra_traits",
::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
$(#[$attr])*
pub struct $i ( $($field)* );
}
)*);
}
/// Implement `Clone` and `Copy` for a struct with no `extra_traits` feature.
///
/// Most items will prefer to use [`s`].
macro_rules! s_no_extra_traits {
($(
$(#[$attr:meta])*
pub $t:ident $i:ident { $($field:tt)* }
)*) => ($(
s_no_extra_traits!(it: $(#[$attr])* pub $t $i { $($field)* });
)*);
(it: $(#[$attr:meta])* pub union $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
$(#[$attr])*
pub union $i { $($field)* }
}
#[cfg(feature = "extra_traits")]
impl ::core::fmt::Debug for $i {
fn fmt(&self, f: &mut ::core::fmt::Formatter<'_>) -> ::core::fmt::Result {
f.debug_struct(::core::stringify!($i)).finish_non_exhaustive()
}
}
);
(it: $(#[$attr:meta])* pub struct $i:ident { $($field:tt)* }) => (
__item! {
#[repr(C)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
$(#[$attr])*
pub struct $i { $($field)* }
}
);
}
/// Specify that an enum should have no traits that aren't specified in the macro
/// invocation, i.e. no `Clone` or `Copy`.
macro_rules! missing {
($(
$(#[$attr:meta])*
pub enum $i:ident {}
)*) => ($(
$(#[$attr])*
#[allow(missing_copy_implementations)]
pub enum $i { }
)*);
}
/// Implement `Clone` and `Copy` for an enum, as well as `Debug`, `Eq`, `Hash`, and
/// `PartialEq` if the `extra_traits` feature is enabled.
macro_rules! e {
($(
$(#[$attr:meta])*
pub enum $i:ident { $($field:tt)* }
)*) => ($(
__item! {
#[cfg_attr(
feature = "extra_traits",
::core::prelude::v1::derive(Debug, Eq, Hash, PartialEq)
)]
#[::core::prelude::v1::derive(::core::clone::Clone, ::core::marker::Copy)]
$(#[$attr])*
pub enum $i { $($field)* }
}
)*);
}
// This is a pretty horrible hack to allow us to conditionally mark some functions as 'const',
// without requiring users of this macro to care "libc_const_extern_fn".
//
// When 'libc_const_extern_fn' is enabled, we emit the captured 'const' keyword in the expanded
// function.
//
// When 'libc_const_extern_fn' is disabled, we always emit a plain 'pub unsafe extern fn'.
// Note that the expression matched by the macro is exactly the same - this allows
// users of this macro to work whether or not 'libc_const_extern_fn' is enabled
//
// Unfortunately, we need to duplicate most of this macro between the 'cfg_if' blocks.
// This is because 'const unsafe extern fn' won't even parse on older compilers,
// so we need to avoid emitting it at all of 'libc_const_extern_fn'.
//
// Specifically, moving the 'cfg_if' into the macro body will *not* work. Doing so would cause the
// '#[cfg(libc_const_extern_fn)]' to be emitted into user code. The 'cfg' gate will not stop Rust
// from trying to parse the 'pub const unsafe extern fn', so users would get a compiler error even
// when the 'libc_const_extern_fn' feature is disabled.
// FIXME(ctest): ctest can't handle `const extern` functions, we should be able to remove this
// cfg completely.
// FIXME(ctest): ctest can't handle `$(,)?` so we use `$(,)*` which isn't quite correct.
cfg_if! {
if #[cfg(libc_const_extern_fn)] {
/// Define an `unsafe` function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! f {
($(
$(#[$attr:meta])*
pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
pub $($constness)* unsafe extern "C" fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
/// Define a safe function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! safe_f {
($(
$(#[$attr:meta])*
pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
pub $($constness)* extern "C" fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
/// A nonpublic function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! const_fn {
($(
$(#[$attr:meta])*
$({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
$($constness)* fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
} else {
/// Define an `unsafe` function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! f {
($(
$(#[$attr:meta])*
pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
pub unsafe extern "C" fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
/// Define a safe function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! safe_f {
($(
$(#[$attr:meta])*
pub $({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
pub extern "C" fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
/// A nonpublic function that is const as long as `libc_const_extern_fn` is enabled.
macro_rules! const_fn {
($(
$(#[$attr:meta])*
$({$constness:ident})* fn $i:ident($($arg:ident: $argty:ty),* $(,)*) -> $ret:ty
$body:block
)*) => ($(
#[inline]
$(#[$attr])*
fn $i($($arg: $argty),*) -> $ret
$body
)*)
}
}
}
macro_rules! __item {
($i:item) => {
$i
};
}
// This macro is used to deprecate items that should be accessed via the mach2 crate
macro_rules! deprecated_mach {
(pub const $id:ident: $ty:ty = $expr:expr;) => {
#[deprecated(
since = "0.2.55",
note = "Use the `mach2` crate instead",
)]
#[allow(deprecated)]
pub const $id: $ty = $expr;
};
($(pub const $id:ident: $ty:ty = $expr:expr;)*) => {
$(
deprecated_mach!(
pub const $id: $ty = $expr;
);
)*
};
(pub type $id:ident = $ty:ty;) => {
#[deprecated(
since = "0.2.55",
note = "Use the `mach2` crate instead",
)]
#[allow(deprecated)]
pub type $id = $ty;
};
($(pub type $id:ident = $ty:ty;)*) => {
$(
deprecated_mach!(
pub type $id = $ty;
);
)*
}
}