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|
//! Generate the internal `bitflags`-facing flags type.
//!
//! The code generated here is owned by `bitflags`, but still part of its public API.
//! Changes to the types generated here need to be considered like any other public API change.
/// Declare the `bitflags`-facing bitflags struct.
///
/// This type is part of the `bitflags` crate's public API, but not part of the user's.
#[macro_export(local_inner_macros)]
#[doc(hidden)]
macro_rules! __declare_internal_bitflags {
(
$vis:vis struct $InternalBitFlags:ident: $T:ty
) => {
// NOTE: The ABI of this type is _guaranteed_ to be the same as `T`
// This is relied on by some external libraries like `bytemuck` to make
// its `unsafe` trait impls sound.
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[repr(transparent)]
$vis struct $InternalBitFlags($T);
};
}
/// Implement functions on the private (bitflags-facing) bitflags type.
///
/// Methods and trait implementations can be freely added here without breaking end-users.
/// If we want to expose new functionality to `#[derive]`, this is the place to do it.
#[macro_export(local_inner_macros)]
#[doc(hidden)]
macro_rules! __impl_internal_bitflags {
(
$InternalBitFlags:ident: $T:ty, $PublicBitFlags:ident {
$(
$(#[$attr:ident $($args:tt)*])*
$Flag:ident = $value:expr;
)*
}
) => {
// NOTE: This impl is also used to prevent using bits types from non-primitive types
// in the `bitflags` macro. If this approach is changed, this guard will need to be
// retained somehow
impl $crate::__private::PublicFlags for $PublicBitFlags {
type Primitive = $T;
type Internal = $InternalBitFlags;
}
impl $crate::__private::core::default::Default for $InternalBitFlags {
#[inline]
fn default() -> Self {
$InternalBitFlags::empty()
}
}
impl $crate::__private::core::fmt::Debug for $InternalBitFlags {
fn fmt(&self, f: &mut $crate::__private::core::fmt::Formatter<'_>) -> $crate::__private::core::fmt::Result {
if self.is_empty() {
// If no flags are set then write an empty hex flag to avoid
// writing an empty string. In some contexts, like serialization,
// an empty string is preferrable, but it may be unexpected in
// others for a format not to produce any output.
//
// We can remove this `0x0` and remain compatible with `FromStr`,
// because an empty string will still parse to an empty set of flags,
// just like `0x0` does.
$crate::__private::core::write!(f, "{:#x}", <$T as $crate::Bits>::EMPTY)
} else {
$crate::__private::core::fmt::Display::fmt(self, f)
}
}
}
impl $crate::__private::core::fmt::Display for $InternalBitFlags {
fn fmt(&self, f: &mut $crate::__private::core::fmt::Formatter<'_>) -> $crate::__private::core::fmt::Result {
$crate::parser::to_writer(&$PublicBitFlags(*self), f)
}
}
impl $crate::__private::core::str::FromStr for $InternalBitFlags {
type Err = $crate::parser::ParseError;
fn from_str(s: &str) -> $crate::__private::core::result::Result<Self, Self::Err> {
$crate::parser::from_str::<$PublicBitFlags>(s).map(|flags| flags.0)
}
}
impl $crate::__private::core::convert::AsRef<$T> for $InternalBitFlags {
fn as_ref(&self) -> &$T {
&self.0
}
}
impl $crate::__private::core::convert::From<$T> for $InternalBitFlags {
fn from(bits: $T) -> Self {
Self::from_bits_retain(bits)
}
}
// The internal flags type offers a similar API to the public one
__impl_public_bitflags! {
$InternalBitFlags: $T, $PublicBitFlags {
$(
$(#[$attr $($args)*])*
$Flag;
)*
}
}
__impl_public_bitflags_iter! {
$InternalBitFlags: $T, $PublicBitFlags
}
impl $InternalBitFlags {
/// Returns a mutable reference to the raw value of the flags currently stored.
#[inline]
pub fn bits_mut(&mut self) -> &mut $T {
&mut self.0
}
}
};
}
|
