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