Adding upstream version 110.0.1.upstream/110.0.1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 584 insertions, 0 deletions

diff --git a/third_party/rust/pin-project-internal/src/lib.rs b/third_party/rust/pin-project-internal/src/lib.rs
new file mode 100644
index 0000000000..07683c417e
--- /dev/null
+++ b/third_party/rust/pin-project-internal/src/lib.rs
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+//! Implementation detail of the `pin-project` crate. - **do not use directly**
+
+#![doc(test(
+    no_crate_inject,
+    attr(
+        deny(warnings, rust_2018_idioms, single_use_lifetimes),
+        allow(dead_code, unused_variables)
+    )
+))]
+#![forbid(unsafe_code)]
+#![warn(rust_2018_idioms, single_use_lifetimes, unreachable_pub)]
+#![warn(clippy::pedantic)]
+#![allow(
+    clippy::needless_doctest_main,
+    clippy::similar_names,
+    clippy::single_match_else,
+    clippy::too_many_lines,
+    clippy::unnested_or_patterns
+)]
+
+// older compilers require explicit `extern crate`.
+#[allow(unused_extern_crates)]
+extern crate proc_macro;
+
+#[macro_use]
+mod utils;
+
+mod pin_project;
+mod pinned_drop;
+
+use proc_macro::TokenStream;
+
+/// An attribute that creates projection types covering all the fields of
+/// struct or enum.
+///
+/// This attribute creates projection types according to the following rules:
+///
+/// - For the fields that use `#[pin]` attribute, create the pinned reference to
+///   the field.
+/// - For the other fields, create a normal reference to the field.
+///
+/// And the following methods are implemented on the original type:
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// # type Projection<'a> = &'a ();
+/// # type ProjectionRef<'a> = &'a ();
+/// # trait Dox {
+/// fn project(self: Pin<&mut Self>) -> Projection<'_>;
+/// fn project_ref(self: Pin<&Self>) -> ProjectionRef<'_>;
+/// # }
+/// ```
+///
+/// By passing an argument with the same name as the method to the attribute,
+/// you can name the projection type returned from the method. This allows you
+/// to use pattern matching on the projected types.
+///
+/// ```rust
+/// # use pin_project::pin_project;
+/// # use std::pin::Pin;
+/// #[pin_project(project = EnumProj)]
+/// enum Enum<T> {
+///     Variant(#[pin] T),
+/// }
+///
+/// impl<T> Enum<T> {
+///     fn method(self: Pin<&mut Self>) {
+///         let this: EnumProj<'_, T> = self.project();
+///         match this {
+///             EnumProj::Variant(x) => {
+///                 let _: Pin<&mut T> = x;
+///             }
+///         }
+///     }
+/// }
+/// ```
+///
+/// Note that the projection types returned by `project` and `project_ref` have
+/// an additional lifetime at the beginning of generics.
+///
+/// ```text
+/// let this: EnumProj<'_, T> = self.project();
+///                    ^^
+/// ```
+///
+/// The visibility of the projected types and projection methods is based on the
+/// original type. However, if the visibility of the original type is `pub`, the
+/// visibility of the projected types and the projection methods is downgraded
+/// to `pub(crate)`.
+///
+/// # Safety
+///
+/// This attribute is completely safe. In the absence of other `unsafe` code
+/// *that you write*, it is impossible to cause [undefined
+/// behavior][undefined-behavior] with this attribute.
+///
+/// This is accomplished by enforcing the four requirements for pin projection
+/// stated in [the Rust documentation][pin-projection]:
+///
+/// 1. The struct must only be [`Unpin`] if all the structural fields are
+///    [`Unpin`].
+///
+///    To enforce this, this attribute will automatically generate an [`Unpin`]
+///    implementation for you, which will require that all structurally pinned
+///    fields be [`Unpin`].
+///
+///    If you attempt to provide an [`Unpin`] impl, the blanket impl will then
+///    apply to your type, causing a compile-time error due to the conflict with
+///    the second impl.
+///
+///    If you wish to provide a manual [`Unpin`] impl, you can do so via the
+///    [`UnsafeUnpin`][unsafe-unpin] argument.
+///
+/// 2. The destructor of the struct must not move structural fields out of its
+///    argument.
+///
+///    To enforce this, this attribute will generate code like this:
+///
+///    ```rust
+///    struct MyStruct {}
+///    trait MyStructMustNotImplDrop {}
+///    # #[allow(unknown_lints, drop_bounds)]
+///    impl<T: Drop> MyStructMustNotImplDrop for T {}
+///    impl MyStructMustNotImplDrop for MyStruct {}
+///    ```
+///
+///    If you attempt to provide an [`Drop`] impl, the blanket impl will then
+///    apply to your type, causing a compile-time error due to the conflict with
+///    the second impl.
+///
+///    If you wish to provide a custom [`Drop`] impl, you can annotate an impl
+///    with [`#[pinned_drop]`][pinned-drop]. This impl takes a pinned version of
+///    your struct - that is, [`Pin`]`<&mut MyStruct>` where `MyStruct` is the
+///    type of your struct.
+///
+///    You can call `.project()` on this type as usual, along with any other
+///    methods you have defined. Because your code is never provided with
+///    a `&mut MyStruct`, it is impossible to move out of pin-projectable
+///    fields in safe code in your destructor.
+///
+/// 3. You must make sure that you uphold the [`Drop`
+///    guarantee][drop-guarantee]: once your struct is pinned, the memory that
+///    contains the content is not overwritten or deallocated without calling
+///    the content's destructors.
+///
+///    Safe code doesn't need to worry about this - the only way to violate
+///    this requirement is to manually deallocate memory (which is `unsafe`),
+///    or to overwrite a field with something else.
+///    Because your custom destructor takes [`Pin`]`<&mut MyStruct>`, it's
+///    impossible to obtain a mutable reference to a pin-projected field in safe
+///    code.
+///
+/// 4. You must not offer any other operations that could lead to data being
+///    moved out of the structural fields when your type is pinned.
+///
+///    As with requirement 3, it is impossible for safe code to violate this.
+///    This crate ensures that safe code can never obtain a mutable reference to
+///    `#[pin]` fields, which prevents you from ever moving out of them in safe
+///    code.
+///
+/// Pin projections are also incompatible with [`#[repr(packed)]`][repr-packed]
+/// types. Attempting to use this attribute on a `#[repr(packed)]` type results
+/// in a compile-time error.
+///
+/// # Examples
+///
+/// `#[pin_project]` can be used on structs and enums.
+///
+/// ```rust
+/// use std::pin::Pin;
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project]
+/// struct Struct<T, U> {
+///     #[pin]
+///     pinned: T,
+///     unpinned: U,
+/// }
+///
+/// impl<T, U> Struct<T, U> {
+///     fn method(self: Pin<&mut Self>) {
+///         let this = self.project();
+///         let _: Pin<&mut T> = this.pinned;
+///         let _: &mut U = this.unpinned;
+///     }
+/// }
+/// ```
+///
+/// ```rust
+/// use std::pin::Pin;
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project]
+/// struct TupleStruct<T, U>(#[pin] T, U);
+///
+/// impl<T, U> TupleStruct<T, U> {
+///     fn method(self: Pin<&mut Self>) {
+///         let this = self.project();
+///         let _: Pin<&mut T> = this.0;
+///         let _: &mut U = this.1;
+///     }
+/// }
+/// ```
+///
+/// To use `#[pin_project]` on enums, you need to name the projection type
+/// returned from the method.
+///
+/// ```rust
+/// use std::pin::Pin;
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project(project = EnumProj)]
+/// enum Enum<T, U> {
+///     Tuple(#[pin] T),
+///     Struct { field: U },
+///     Unit,
+/// }
+///
+/// impl<T, U> Enum<T, U> {
+///     fn method(self: Pin<&mut Self>) {
+///         match self.project() {
+///             EnumProj::Tuple(x) => {
+///                 let _: Pin<&mut T> = x;
+///             }
+///             EnumProj::Struct { field } => {
+///                 let _: &mut U = field;
+///             }
+///             EnumProj::Unit => {}
+///         }
+///     }
+/// }
+/// ```
+///
+/// When `#[pin_project]` is used on enums, only named projection types and
+/// methods are generated because there is no way to access variants of
+/// projected types without naming it.
+/// For example, in the above example, only the `project` method is generated,
+/// and the `project_ref` method is not generated.
+/// (When `#[pin_project]` is used on structs, both methods are always generated.)
+///
+/// ```rust,compile_fail,E0599
+/// # use pin_project::pin_project;
+/// # use std::pin::Pin;
+/// #
+/// # #[pin_project(project = EnumProj)]
+/// # enum Enum<T, U> {
+/// #     Tuple(#[pin] T),
+/// #     Struct { field: U },
+/// #     Unit,
+/// # }
+/// #
+/// impl<T, U> Enum<T, U> {
+///     fn call_project_ref(self: Pin<&Self>) {
+///         let _this = self.project_ref();
+///         //~^ ERROR no method named `project_ref` found for struct `Pin<&Enum<T, U>>` in the current scope
+///     }
+/// }
+/// ```
+///
+/// If you want to call `.project()` multiple times or later use the
+/// original [`Pin`] type, it needs to use [`.as_mut()`][`Pin::as_mut`] to avoid
+/// consuming the [`Pin`].
+///
+/// ```rust
+/// use std::pin::Pin;
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project]
+/// struct Struct<T> {
+///     #[pin]
+///     field: T,
+/// }
+///
+/// impl<T> Struct<T> {
+///     fn call_project_twice(mut self: Pin<&mut Self>) {
+///         // `project` consumes `self`, so reborrow the `Pin<&mut Self>` via `as_mut`.
+///         self.as_mut().project();
+///         self.as_mut().project();
+///     }
+/// }
+/// ```
+///
+/// # `!Unpin`
+///
+/// If you want to ensure that [`Unpin`] is not implemented, use the `!Unpin`
+/// argument to `#[pin_project]`.
+///
+/// ```rust
+/// use pin_project::pin_project;
+///
+/// #[pin_project(!Unpin)]
+/// struct Struct<T> {
+///     field: T,
+/// }
+/// ```
+///
+/// This is equivalent to using `#[pin]` attribute for the [`PhantomPinned`]
+/// field.
+///
+/// ```rust
+/// use std::marker::PhantomPinned;
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project]
+/// struct Struct<T> {
+///     field: T,
+///     #[pin] // <------ This `#[pin]` is required to make `Struct` to `!Unpin`.
+///     _pin: PhantomPinned,
+/// }
+/// ```
+///
+/// Note that using [`PhantomPinned`] without `#[pin]` attribute has no effect.
+///
+/// # `UnsafeUnpin`
+///
+/// If you want to implement [`Unpin`] manually, you must use the `UnsafeUnpin`
+/// argument to `#[pin_project]`.
+///
+/// ```rust
+/// use pin_project::{pin_project, UnsafeUnpin};
+///
+/// #[pin_project(UnsafeUnpin)]
+/// struct Struct<T, U> {
+///     #[pin]
+///     pinned: T,
+///     unpinned: U,
+/// }
+///
+/// unsafe impl<T: Unpin, U> UnsafeUnpin for Struct<T, U> {}
+/// ```
+///
+/// Note the usage of the unsafe [`UnsafeUnpin`] trait, instead of the usual
+/// [`Unpin`] trait. [`UnsafeUnpin`] behaves exactly like [`Unpin`], except that
+/// is unsafe to implement. This unsafety comes from the fact that pin
+/// projections are being used. If you implement [`UnsafeUnpin`], you must
+/// ensure that it is only implemented when all pin-projected fields implement
+/// [`Unpin`].
+///
+/// See [`UnsafeUnpin`] trait for more details.
+///
+/// # `#[pinned_drop]`
+///
+/// In order to correctly implement pin projections, a type's [`Drop`] impl must
+/// not move out of any structurally pinned fields. Unfortunately,
+/// [`Drop::drop`] takes `&mut Self`, not [`Pin`]`<&mut Self>`.
+///
+/// To ensure that this requirement is upheld, the `#[pin_project]` attribute
+/// will provide a [`Drop`] impl for you. This [`Drop`] impl will delegate to
+/// an impl block annotated with `#[pinned_drop]` if you use the `PinnedDrop`
+/// argument to `#[pin_project]`.
+///
+/// This impl block acts just like a normal [`Drop`] impl,
+/// except for the following two:
+///
+/// - `drop` method takes [`Pin`]`<&mut Self>`
+/// - Name of the trait is `PinnedDrop`.
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// pub trait PinnedDrop {
+///     fn drop(self: Pin<&mut Self>);
+/// }
+/// ```
+///
+/// `#[pin_project]` implements the actual [`Drop`] trait via `PinnedDrop` you
+/// implemented. To drop a type that implements `PinnedDrop`, use the [`drop`]
+/// function just like dropping a type that directly implements [`Drop`].
+///
+/// In particular, it will never be called more than once, just like
+/// [`Drop::drop`].
+///
+/// For example:
+///
+/// ```rust
+/// use std::{fmt::Debug, pin::Pin};
+///
+/// use pin_project::{pin_project, pinned_drop};
+///
+/// #[pin_project(PinnedDrop)]
+/// struct PrintOnDrop<T: Debug, U: Debug> {
+///     #[pin]
+///     pinned_field: T,
+///     unpin_field: U,
+/// }
+///
+/// #[pinned_drop]
+/// impl<T: Debug, U: Debug> PinnedDrop for PrintOnDrop<T, U> {
+///     fn drop(self: Pin<&mut Self>) {
+///         println!("Dropping pinned field: {:?}", self.pinned_field);
+///         println!("Dropping unpin field: {:?}", self.unpin_field);
+///     }
+/// }
+///
+/// fn main() {
+///     let _x = PrintOnDrop { pinned_field: true, unpin_field: 40 };
+/// }
+/// ```
+///
+/// See also [`#[pinned_drop]`][macro@pinned_drop] attribute.
+///
+/// # `project_replace` method
+///
+/// In addition to the `project` and `project_ref` methods which are always
+/// provided when you use the `#[pin_project]` attribute, there is a third
+/// method, `project_replace` which can be useful in some situations. It is
+/// equivalent to [`Pin::set`], except that the unpinned fields are moved and
+/// returned, instead of being dropped in-place.
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// # type ProjectionOwned = ();
+/// # trait Dox {
+/// fn project_replace(self: Pin<&mut Self>, other: Self) -> ProjectionOwned;
+/// # }
+/// ```
+///
+/// The `ProjectionOwned` type is identical to the `Self` type, except that
+/// all pinned fields have been replaced by equivalent [`PhantomData`] types.
+///
+/// This method is opt-in, because it is only supported for [`Sized`] types, and
+/// because it is incompatible with the [`#[pinned_drop]`][pinned-drop]
+/// attribute described above. It can be enabled by using
+/// `#[pin_project(project_replace)]`.
+///
+/// For example:
+///
+/// ```rust
+/// use std::{marker::PhantomData, pin::Pin};
+///
+/// use pin_project::pin_project;
+///
+/// #[pin_project(project_replace)]
+/// struct Struct<T, U> {
+///     #[pin]
+///     pinned_field: T,
+///     unpinned_field: U,
+/// }
+///
+/// impl<T, U> Struct<T, U> {
+///     fn method(self: Pin<&mut Self>, other: Self) {
+///         let this = self.project_replace(other);
+///         let _: U = this.unpinned_field;
+///         let _: PhantomData<T> = this.pinned_field;
+///     }
+/// }
+/// ```
+///
+/// By passing the value to the `project_replace` argument, you can name the
+/// returned type of the `project_replace` method. This is necessary whenever
+/// destructuring the return type of the `project_replace` method, and work in exactly
+/// the same way as the `project` and `project_ref` arguments.
+///
+/// ```rust
+/// use pin_project::pin_project;
+///
+/// #[pin_project(project_replace = EnumProjOwn)]
+/// enum Enum<T, U> {
+///     A {
+///         #[pin]
+///         pinned_field: T,
+///         unpinned_field: U,
+///     },
+///     B,
+/// }
+///
+/// let mut x = Box::pin(Enum::A { pinned_field: 42, unpinned_field: "hello" });
+///
+/// match x.as_mut().project_replace(Enum::B) {
+///     EnumProjOwn::A { unpinned_field, .. } => assert_eq!(unpinned_field, "hello"),
+///     EnumProjOwn::B => unreachable!(),
+/// }
+/// ```
+///
+/// [`PhantomData`]: core::marker::PhantomData
+/// [`PhantomPinned`]: core::marker::PhantomPinned
+/// [`Pin::as_mut`]: core::pin::Pin::as_mut
+/// [`Pin::set`]: core::pin::Pin::set
+/// [`Pin`]: core::pin::Pin
+/// [`UnsafeUnpin`]: https://docs.rs/pin-project/1/pin_project/trait.UnsafeUnpin.html
+/// [drop-guarantee]: core::pin#drop-guarantee
+/// [pin-projection]: core::pin#projections-and-structural-pinning
+/// [pinned-drop]: macro@pin_project#pinned_drop
+/// [repr-packed]: https://doc.rust-lang.org/nomicon/other-reprs.html#reprpacked
+/// [undefined-behavior]: https://doc.rust-lang.org/reference/behavior-considered-undefined.html
+/// [unsafe-unpin]: macro@pin_project#unsafeunpin
+#[proc_macro_attribute]
+pub fn pin_project(args: TokenStream, input: TokenStream) -> TokenStream {
+    pin_project::attribute(&args.into(), input.into()).into()
+}
+
+/// An attribute used for custom implementations of [`Drop`].
+///
+/// This attribute is used in conjunction with the `PinnedDrop` argument to
+/// the [`#[pin_project]`][macro@pin_project] attribute.
+///
+/// The impl block annotated with this attribute acts just like a normal
+/// [`Drop`] impl, except for the following two:
+///
+/// - `drop` method takes [`Pin`]`<&mut Self>`
+/// - Name of the trait is `PinnedDrop`.
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// pub trait PinnedDrop {
+///     fn drop(self: Pin<&mut Self>);
+/// }
+/// ```
+///
+/// `#[pin_project]` implements the actual [`Drop`] trait via `PinnedDrop` you
+/// implemented. To drop a type that implements `PinnedDrop`, use the [`drop`]
+/// function just like dropping a type that directly implements [`Drop`].
+///
+/// In particular, it will never be called more than once, just like
+/// [`Drop::drop`].
+///
+/// # Examples
+///
+/// ```rust
+/// use std::pin::Pin;
+///
+/// use pin_project::{pin_project, pinned_drop};
+///
+/// #[pin_project(PinnedDrop)]
+/// struct PrintOnDrop {
+///     #[pin]
+///     field: u8,
+/// }
+///
+/// #[pinned_drop]
+/// impl PinnedDrop for PrintOnDrop {
+///     fn drop(self: Pin<&mut Self>) {
+///         println!("Dropping: {}", self.field);
+///     }
+/// }
+///
+/// fn main() {
+///     let _x = PrintOnDrop { field: 50 };
+/// }
+/// ```
+///
+/// See also ["pinned-drop" section of `#[pin_project]` attribute][pinned-drop].
+///
+/// # Why `#[pinned_drop]` attribute is needed?
+///
+/// Implementing `PinnedDrop::drop` is safe, but calling it is not safe.
+/// This is because destructors can be called multiple times in safe code and
+/// [double dropping is unsound][rust-lang/rust#62360].
+///
+/// Ideally, it would be desirable to be able to forbid manual calls in
+/// the same way as [`Drop::drop`], but the library cannot do it. So, by using
+/// macros and replacing them with private traits like the following,
+/// this crate prevent users from calling `PinnedDrop::drop` in safe code.
+///
+/// ```rust
+/// # use std::pin::Pin;
+/// pub trait PinnedDrop {
+///     unsafe fn drop(self: Pin<&mut Self>);
+/// }
+/// ```
+///
+/// This allows implementing [`Drop`] safely using `#[pinned_drop]`.
+/// Also by using the [`drop`] function just like dropping a type that directly
+/// implements [`Drop`], can drop safely a type that implements `PinnedDrop`.
+///
+/// [rust-lang/rust#62360]: https://github.com/rust-lang/rust/pull/62360
+/// [`Pin`]: core::pin::Pin
+/// [pinned-drop]: macro@pin_project#pinned_drop
+#[proc_macro_attribute]
+pub fn pinned_drop(args: TokenStream, input: TokenStream) -> TokenStream {
+    let input = syn::parse_macro_input!(input);
+    pinned_drop::attribute(&args.into(), input).into()
+}
+
+// Not public API.
+#[doc(hidden)]
+#[proc_macro_derive(__PinProjectInternalDerive, attributes(pin))]
+pub fn __pin_project_internal_derive(input: TokenStream) -> TokenStream {
+    pin_project::derive(input.into()).into()
+}