| /*! |
| <!-- tidy:crate-doc:start --> |
| A lightweight version of [pin-project] written with declarative macros. |
| |
| ## Usage |
| |
| Add this to your `Cargo.toml`: |
| |
| ```toml |
| [dependencies] |
| pin-project-lite = "0.2" |
| ``` |
| |
| *Compiler support: requires rustc 1.37+* |
| |
| ## Examples |
| |
| [`pin_project!`] macro creates a projection type covering all the fields of |
| struct. |
| |
| ```rust |
| use std::pin::Pin; |
| |
| use pin_project_lite::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; // Pinned reference to the field |
| let _: &mut U = this.unpinned; // Normal reference to the field |
| } |
| } |
| ``` |
| |
| 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_lite::pin_project; |
| |
| pin_project! { |
| #[project = EnumProj] |
| enum Enum<T, U> { |
| Variant { #[pin] pinned: T, unpinned: U }, |
| } |
| } |
| |
| impl<T, U> Enum<T, U> { |
| fn method(self: Pin<&mut Self>) { |
| match self.project() { |
| EnumProj::Variant { pinned, unpinned } => { |
| let _: Pin<&mut T> = pinned; |
| let _: &mut U = unpinned; |
| } |
| } |
| } |
| } |
| ``` |
| |
| ## [pin-project] vs pin-project-lite |
| |
| Here are some similarities and differences compared to [pin-project]. |
| |
| ### Similar: Safety |
| |
| pin-project-lite guarantees safety in much the same way as [pin-project]. |
| Both are completely safe unless you write other unsafe code. |
| |
| ### Different: Minimal design |
| |
| This library does not tackle as expansive of a range of use cases as |
| [pin-project] does. If your use case is not already covered, please use |
| [pin-project]. |
| |
| ### Different: No proc-macro related dependencies |
| |
| This is the **only** reason to use this crate. However, **if you already |
| have proc-macro related dependencies in your crate's dependency graph, there |
| is no benefit from using this crate.** (Note: There is almost no difference |
| in the amount of code generated between [pin-project] and pin-project-lite.) |
| |
| ### Different: No useful error messages |
| |
| This macro does not handle any invalid input. So error messages are not to |
| be useful in most cases. If you do need useful error messages, then upon |
| error you can pass the same input to [pin-project] to receive a helpful |
| description of the compile error. |
| |
| ### Different: No support for custom Unpin implementation |
| |
| pin-project supports this by [`UnsafeUnpin`][unsafe-unpin] and [`!Unpin`][not-unpin]. |
| |
| ### Different: No support for tuple structs and tuple variants |
| |
| pin-project supports this. |
| |
| [not-unpin]: https://docs.rs/pin-project/1/pin_project/attr.pin_project.html#unpin |
| [pin-project]: https://github.com/taiki-e/pin-project |
| [unsafe-unpin]: https://docs.rs/pin-project/1/pin_project/attr.pin_project.html#unsafeunpin |
| |
| <!-- tidy:crate-doc:end --> |
| */ |
| |
| #![no_std] |
| #![doc(test( |
| no_crate_inject, |
| attr( |
| deny(warnings, rust_2018_idioms, single_use_lifetimes), |
| allow(dead_code, unused_variables) |
| ) |
| ))] |
| #![warn(rust_2018_idioms, single_use_lifetimes, unreachable_pub)] |
| #![warn( |
| clippy::pedantic, |
| // lints for public library |
| clippy::alloc_instead_of_core, |
| clippy::exhaustive_enums, |
| clippy::exhaustive_structs, |
| clippy::std_instead_of_alloc, |
| clippy::std_instead_of_core, |
| // lints that help writing unsafe code |
| clippy::as_ptr_cast_mut, |
| clippy::default_union_representation, |
| clippy::trailing_empty_array, |
| clippy::transmute_undefined_repr, |
| clippy::undocumented_unsafe_blocks, |
| )] |
| |
| /// A macro that creates a projection type covering all the fields of struct. |
| /// |
| /// This macro creates a projection type according to the following rules: |
| /// |
| /// - For the field that uses `#[pin]` attribute, makes the pinned reference to the field. |
| /// - For the other fields, makes the unpinned 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 attribute with the same name as the method to the macro, |
| /// 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_lite::pin_project; |
| /// # use std::pin::Pin; |
| /// pin_project! { |
| /// #[project = EnumProj] |
| /// enum Enum<T> { |
| /// Variant { #[pin] field: T }, |
| /// } |
| /// } |
| /// |
| /// impl<T> Enum<T> { |
| /// fn method(self: Pin<&mut Self>) { |
| /// let this: EnumProj<'_, T> = self.project(); |
| /// match this { |
| /// EnumProj::Variant { field } => { |
| /// let _: Pin<&mut T> = field; |
| /// } |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// By passing the `#[project_replace = MyProjReplace]` attribute you may create an additional |
| /// method which allows the contents of `Pin<&mut Self>` to be replaced while simultaneously moving |
| /// out all unpinned fields in `Self`. |
| /// |
| /// ```rust |
| /// # use std::pin::Pin; |
| /// # type MyProjReplace = (); |
| /// # trait Dox { |
| /// fn project_replace(self: Pin<&mut Self>, replacement: Self) -> MyProjReplace; |
| /// # } |
| /// ``` |
| /// |
| /// Also, 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 |
| /// |
| /// `pin_project!` macro guarantees safety in much the same way as [pin-project] crate. |
| /// Both are completely safe unless you write other unsafe code. |
| /// |
| /// See [pin-project] crate for more details. |
| /// |
| /// # Examples |
| /// |
| /// ```rust |
| /// use std::pin::Pin; |
| /// |
| /// use pin_project_lite::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; // Pinned reference to the field |
| /// let _: &mut U = this.unpinned; // Normal reference to the field |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// 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_lite::pin_project; |
| /// |
| /// pin_project! { |
| /// #[project = EnumProj] |
| /// enum Enum<T> { |
| /// Struct { |
| /// #[pin] |
| /// field: T, |
| /// }, |
| /// Unit, |
| /// } |
| /// } |
| /// |
| /// impl<T> Enum<T> { |
| /// fn method(self: Pin<&mut Self>) { |
| /// match self.project() { |
| /// EnumProj::Struct { field } => { |
| /// let _: Pin<&mut T> = field; |
| /// } |
| /// EnumProj::Unit => {} |
| /// } |
| /// } |
| /// } |
| /// ``` |
| /// |
| /// If you want to call the `project()` method 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_lite::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 `#[pin]` |
| /// attribute for a [`PhantomPinned`] field. |
| /// |
| /// ```rust |
| /// use std::marker::PhantomPinned; |
| /// |
| /// use pin_project_lite::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. |
| /// |
| /// [`PhantomPinned`]: core::marker::PhantomPinned |
| /// [`Pin::as_mut`]: core::pin::Pin::as_mut |
| /// [`Pin`]: core::pin::Pin |
| /// [pin-project]: https://github.com/taiki-e/pin-project |
| #[macro_export] |
| macro_rules! pin_project { |
| ($($tt:tt)*) => { |
| $crate::__pin_project_internal! { |
| [][][][] |
| $($tt)* |
| } |
| }; |
| } |
| |
| // limitations: |
| // - no support for tuple structs and tuple variant (wontfix). |
| // - no support for multiple trait/lifetime bounds. |
| // - no support for `Self` in where clauses. (wontfix) |
| // - no support for overlapping lifetime names. (wontfix) |
| // - no interoperability with other field attributes. |
| // - no useful error messages. (wontfix) |
| // etc... |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_expand { |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$proj_vis:vis] |
| [$(#[$attrs:meta])* $vis:vis $struct_ty_ident:ident $ident:ident] |
| [$($def_generics:tt)*] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $($body_data:tt)* |
| } |
| $(impl $($pinned_drop:tt)*)? |
| ) => { |
| $crate::__pin_project_reconstruct! { |
| [$(#[$attrs])* $vis $struct_ty_ident $ident] |
| [$($def_generics)*] [$($impl_generics)*] |
| [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $($body_data)* |
| } |
| } |
| |
| $crate::__pin_project_make_proj_ty! { |
| [$($proj_mut_ident)?] |
| [$proj_vis $struct_ty_ident $ident] |
| [__pin_project_make_proj_field_mut] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $($body_data)* |
| } |
| } |
| $crate::__pin_project_make_proj_ty! { |
| [$($proj_ref_ident)?] |
| [$proj_vis $struct_ty_ident $ident] |
| [__pin_project_make_proj_field_ref] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $($body_data)* |
| } |
| } |
| $crate::__pin_project_make_proj_replace_ty! { |
| [$($proj_replace_ident)?] |
| [$proj_vis $struct_ty_ident] |
| [__pin_project_make_proj_field_replace] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $($body_data)* |
| } |
| } |
| |
| $crate::__pin_project_constant! { |
| [$(#[$attrs])* $vis $struct_ty_ident $ident] |
| [$($proj_mut_ident)?] [$($proj_ref_ident)?] [$($proj_replace_ident)?] |
| [$proj_vis] |
| [$($def_generics)*] [$($impl_generics)*] |
| [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $($body_data)* |
| } |
| $(impl $($pinned_drop)*)? |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_constant { |
| ( |
| [$(#[$attrs:meta])* $vis:vis struct $ident:ident] |
| [$($proj_mut_ident:ident)?] [$($proj_ref_ident:ident)?] [$($proj_replace_ident:ident)?] |
| [$proj_vis:vis] |
| [$($def_generics:tt)*] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident: $field_ty:ty |
| ),+ $(,)? |
| } |
| $(impl $($pinned_drop:tt)*)? |
| ) => { |
| #[allow(explicit_outlives_requirements)] // https://github.com/rust-lang/rust/issues/60993 |
| #[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 |
| // This lint warns of `clippy::*` generated by external macros. |
| // We allow this lint for compatibility with older compilers. |
| #[allow(clippy::unknown_clippy_lints)] |
| #[allow(clippy::redundant_pub_crate)] // This lint warns `pub(crate)` field in private struct. |
| #[allow(clippy::used_underscore_binding)] |
| const _: () = { |
| $crate::__pin_project_make_proj_ty! { |
| [$($proj_mut_ident)? Projection] |
| [$proj_vis struct $ident] |
| [__pin_project_make_proj_field_mut] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $( |
| $(#[$pin])? |
| $field_vis $field: $field_ty |
| ),+ |
| } |
| } |
| $crate::__pin_project_make_proj_ty! { |
| [$($proj_ref_ident)? ProjectionRef] |
| [$proj_vis struct $ident] |
| [__pin_project_make_proj_field_ref] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| { |
| $( |
| $(#[$pin])? |
| $field_vis $field: $field_ty |
| ),+ |
| } |
| } |
| |
| impl <$($impl_generics)*> $ident <$($ty_generics)*> |
| $(where |
| $($where_clause)*)? |
| { |
| $crate::__pin_project_struct_make_proj_method! { |
| [$($proj_mut_ident)? Projection] |
| [$proj_vis] |
| [project get_unchecked_mut mut] |
| [$($ty_generics)*] |
| { |
| $( |
| $(#[$pin])? |
| $field_vis $field |
| ),+ |
| } |
| } |
| $crate::__pin_project_struct_make_proj_method! { |
| [$($proj_ref_ident)? ProjectionRef] |
| [$proj_vis] |
| [project_ref get_ref] |
| [$($ty_generics)*] |
| { |
| $( |
| $(#[$pin])? |
| $field_vis $field |
| ),+ |
| } |
| } |
| $crate::__pin_project_struct_make_proj_replace_method! { |
| [$($proj_replace_ident)?] |
| [$proj_vis] |
| [ProjectionReplace] |
| [$($ty_generics)*] |
| { |
| $( |
| $(#[$pin])? |
| $field_vis $field |
| ),+ |
| } |
| } |
| } |
| |
| $crate::__pin_project_make_unpin_impl! { |
| [$vis $ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| $( |
| $field: $crate::__pin_project_make_unpin_bound!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| } |
| |
| $crate::__pin_project_make_drop_impl! { |
| [$ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| $(impl $($pinned_drop)*)? |
| } |
| |
| // Ensure that it's impossible to use pin projections on a #[repr(packed)] struct. |
| // |
| // Taking a reference to a packed field is UB, and applying |
| // `#[forbid(unaligned_references)]` makes sure that doing this is a hard error. |
| // |
| // If the struct ends up having #[repr(packed)] applied somehow, |
| // this will generate an (unfriendly) error message. Under all reasonable |
| // circumstances, we'll detect the #[repr(packed)] attribute, and generate |
| // a much nicer error above. |
| // |
| // See https://github.com/taiki-e/pin-project/pull/34 for more details. |
| // |
| // Note: |
| // - Lint-based tricks aren't perfect, but they're much better than nothing: |
| // https://github.com/taiki-e/pin-project-lite/issues/26 |
| // |
| // - Enable both unaligned_references and safe_packed_borrows lints |
| // because unaligned_references lint does not exist in older compilers: |
| // https://github.com/taiki-e/pin-project-lite/pull/55 |
| // https://github.com/rust-lang/rust/pull/82525 |
| #[forbid(unaligned_references, safe_packed_borrows)] |
| fn __assert_not_repr_packed <$($impl_generics)*> (this: &$ident <$($ty_generics)*>) |
| $(where |
| $($where_clause)*)? |
| { |
| $( |
| let _ = &this.$field; |
| )+ |
| } |
| }; |
| }; |
| ( |
| [$(#[$attrs:meta])* $vis:vis enum $ident:ident] |
| [$($proj_mut_ident:ident)?] [$($proj_ref_ident:ident)?] [$($proj_replace_ident:ident)?] |
| [$proj_vis:vis] |
| [$($def_generics:tt)*] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$variant_attrs:meta])* |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident: $field_ty:ty |
| ),+ $(,)? |
| })? |
| ),+ $(,)? |
| } |
| $(impl $($pinned_drop:tt)*)? |
| ) => { |
| #[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 |
| // This lint warns of `clippy::*` generated by external macros. |
| // We allow this lint for compatibility with older compilers. |
| #[allow(clippy::unknown_clippy_lints)] |
| #[allow(clippy::used_underscore_binding)] |
| const _: () = { |
| impl <$($impl_generics)*> $ident <$($ty_generics)*> |
| $(where |
| $($where_clause)*)? |
| { |
| $crate::__pin_project_enum_make_proj_method! { |
| [$($proj_mut_ident)?] |
| [$proj_vis] |
| [project get_unchecked_mut mut] |
| [$($ty_generics)*] |
| { |
| $( |
| $variant $({ |
| $( |
| $(#[$pin])? |
| $field |
| ),+ |
| })? |
| ),+ |
| } |
| } |
| $crate::__pin_project_enum_make_proj_method! { |
| [$($proj_ref_ident)?] |
| [$proj_vis] |
| [project_ref get_ref] |
| [$($ty_generics)*] |
| { |
| $( |
| $variant $({ |
| $( |
| $(#[$pin])? |
| $field |
| ),+ |
| })? |
| ),+ |
| } |
| } |
| $crate::__pin_project_enum_make_proj_replace_method! { |
| [$($proj_replace_ident)?] |
| [$proj_vis] |
| [$($ty_generics)*] |
| { |
| $( |
| $variant $({ |
| $( |
| $(#[$pin])? |
| $field |
| ),+ |
| })? |
| ),+ |
| } |
| } |
| } |
| |
| $crate::__pin_project_make_unpin_impl! { |
| [$vis $ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| $( |
| $variant: ($( |
| $( |
| $crate::__pin_project_make_unpin_bound!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| )?) |
| ),+ |
| } |
| |
| $crate::__pin_project_make_drop_impl! { |
| [$ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| $(impl $($pinned_drop)*)? |
| } |
| |
| // We don't need to check for '#[repr(packed)]', |
| // since it does not apply to enums. |
| }; |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_reconstruct { |
| ( |
| [$(#[$attrs:meta])* $vis:vis struct $ident:ident] |
| [$($def_generics:tt)*] [$($impl_generics:tt)*] |
| [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident: $field_ty:ty |
| ),+ $(,)? |
| } |
| ) => { |
| $(#[$attrs])* |
| $vis struct $ident $($def_generics)* |
| $(where |
| $($where_clause)*)? |
| { |
| $( |
| $field_vis $field: $field_ty |
| ),+ |
| } |
| }; |
| ( |
| [$(#[$attrs:meta])* $vis:vis enum $ident:ident] |
| [$($def_generics:tt)*] [$($impl_generics:tt)*] |
| [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$variant_attrs:meta])* |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident: $field_ty:ty |
| ),+ $(,)? |
| })? |
| ),+ $(,)? |
| } |
| ) => { |
| $(#[$attrs])* |
| $vis enum $ident $($def_generics)* |
| $(where |
| $($where_clause)*)? |
| { |
| $( |
| $(#[$variant_attrs])* |
| $variant $({ |
| $( |
| $field: $field_ty |
| ),+ |
| })? |
| ),+ |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_ty { |
| ([] $($field:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident $default_ident:ident] |
| [$proj_vis:vis struct $ident:ident] |
| $($field:tt)* |
| ) => {}; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis struct $ident:ident] |
| [$__pin_project_make_proj_field:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident: $field_ty:ty |
| ),+ $(,)? |
| } |
| ) => { |
| $crate::__pin_project_make_proj_ty_body! { |
| [$proj_ty_ident] |
| [$proj_vis struct $ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| [ |
| $( |
| $field_vis $field: $crate::$__pin_project_make_proj_field!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| ] |
| } |
| }; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis enum $ident:ident] |
| [$__pin_project_make_proj_field:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$variant_attrs:meta])* |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident: $field_ty:ty |
| ),+ $(,)? |
| })? |
| ),+ $(,)? |
| } |
| ) => { |
| $crate::__pin_project_make_proj_ty_body! { |
| [$proj_ty_ident] |
| [$proj_vis enum $ident] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| [ |
| $( |
| $variant $({ |
| $( |
| $field: $crate::$__pin_project_make_proj_field!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| })? |
| ),+ |
| ] |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_ty_body { |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis $struct_ty_ident:ident $ident:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| [$($body_data:tt)+] |
| ) => { |
| #[allow(dead_code)] // This lint warns unused fields/variants. |
| #[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 |
| // This lint warns of `clippy::*` generated by external macros. |
| // We allow this lint for compatibility with older compilers. |
| #[allow(clippy::unknown_clippy_lints)] |
| #[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`. (only needed for project) |
| #[allow(clippy::redundant_pub_crate)] // This lint warns `pub(crate)` field in private struct. |
| #[allow(clippy::ref_option_ref)] // This lint warns `&Option<&<ty>>`. (only needed for project_ref) |
| #[allow(clippy::type_repetition_in_bounds)] // https://github.com/rust-lang/rust-clippy/issues/4326 |
| $proj_vis $struct_ty_ident $proj_ty_ident <'__pin, $($impl_generics)*> |
| where |
| $ident <$($ty_generics)*>: '__pin |
| $(, $($where_clause)*)? |
| { |
| $($body_data)+ |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_replace_ty { |
| ([] $($field:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis struct] |
| [$__pin_project_make_proj_field:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident: $field_ty:ty |
| ),+ $(,)? |
| } |
| ) => { |
| $crate::__pin_project_make_proj_replace_ty_body! { |
| [$proj_ty_ident] |
| [$proj_vis struct] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| [ |
| $( |
| $field_vis $field: $crate::$__pin_project_make_proj_field!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| ] |
| } |
| }; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis enum] |
| [$__pin_project_make_proj_field:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| { |
| $( |
| $(#[$variant_attrs:meta])* |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident: $field_ty:ty |
| ),+ $(,)? |
| })? |
| ),+ $(,)? |
| } |
| ) => { |
| $crate::__pin_project_make_proj_replace_ty_body! { |
| [$proj_ty_ident] |
| [$proj_vis enum] |
| [$($impl_generics)*] [$($ty_generics)*] [$(where $($where_clause)*)?] |
| [ |
| $( |
| $variant $({ |
| $( |
| $field: $crate::$__pin_project_make_proj_field!( |
| $(#[$pin])? $field_ty |
| ) |
| ),+ |
| })? |
| ),+ |
| ] |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_replace_ty_body { |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis $struct_ty_ident:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| [$($body_data:tt)+] |
| ) => { |
| #[allow(dead_code)] // This lint warns unused fields/variants. |
| #[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058 |
| #[allow(clippy::mut_mut)] // This lint warns `&mut &mut <ty>`. (only needed for project) |
| #[allow(clippy::redundant_pub_crate)] // This lint warns `pub(crate)` field in private struct. |
| #[allow(clippy::type_repetition_in_bounds)] // https://github.com/rust-lang/rust-clippy/issues/4326 |
| $proj_vis $struct_ty_ident $proj_ty_ident <$($impl_generics)*> |
| where |
| $($($where_clause)*)? |
| { |
| $($body_data)+ |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_replace_block { |
| ( |
| [$($proj_path:tt)+] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident |
| ),+ |
| } |
| ) => { |
| let result = $($proj_path)* { |
| $( |
| $field: $crate::__pin_project_make_replace_field_proj!( |
| $(#[$pin])? $field |
| ) |
| ),+ |
| }; |
| |
| { |
| ( $( |
| $crate::__pin_project_make_unsafe_drop_in_place_guard!( |
| $(#[$pin])? $field |
| ), |
| )* ); |
| } |
| |
| result |
| }; |
| ([$($proj_path:tt)+]) => { $($proj_path)* }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_struct_make_proj_method { |
| ([] $($variant:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident $_ignored_default_arg:ident] |
| [$proj_vis:vis] |
| [$method_ident:ident $get_method:ident $($mut:ident)?] |
| [$($ty_generics:tt)*] |
| $($variant:tt)* |
| ) => { |
| $crate::__pin_project_struct_make_proj_method! { |
| [$proj_ty_ident] |
| [$proj_vis] |
| [$method_ident $get_method $($mut)?] |
| [$($ty_generics)*] |
| $($variant)* |
| } |
| }; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis] |
| [$method_ident:ident $get_method:ident $($mut:ident)?] |
| [$($ty_generics:tt)*] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident |
| ),+ |
| } |
| ) => { |
| #[inline] |
| $proj_vis fn $method_ident<'__pin>( |
| self: $crate::__private::Pin<&'__pin $($mut)? Self>, |
| ) -> $proj_ty_ident <'__pin, $($ty_generics)*> { |
| unsafe { |
| let Self { $($field),* } = self.$get_method(); |
| $proj_ty_ident { |
| $( |
| $field: $crate::__pin_project_make_unsafe_field_proj!( |
| $(#[$pin])? $field |
| ) |
| ),+ |
| } |
| } |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_struct_make_proj_replace_method { |
| ([] $($field:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis] |
| [$_proj_ty_ident:ident] |
| [$($ty_generics:tt)*] |
| { |
| $( |
| $(#[$pin:ident])? |
| $field_vis:vis $field:ident |
| ),+ |
| } |
| ) => { |
| #[inline] |
| $proj_vis fn project_replace( |
| self: $crate::__private::Pin<&mut Self>, |
| replacement: Self, |
| ) -> $proj_ty_ident <$($ty_generics)*> { |
| unsafe { |
| let __self_ptr: *mut Self = self.get_unchecked_mut(); |
| |
| // Destructors will run in reverse order, so next create a guard to overwrite |
| // `self` with the replacement value without calling destructors. |
| let __guard = $crate::__private::UnsafeOverwriteGuard::new(__self_ptr, replacement); |
| |
| let Self { $($field),* } = &mut *__self_ptr; |
| |
| $crate::__pin_project_make_proj_replace_block! { |
| [$proj_ty_ident] |
| { |
| $( |
| $(#[$pin])? |
| $field |
| ),+ |
| } |
| } |
| } |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_enum_make_proj_method { |
| ([] $($variant:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis] |
| [$method_ident:ident $get_method:ident $($mut:ident)?] |
| [$($ty_generics:tt)*] |
| { |
| $( |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident |
| ),+ |
| })? |
| ),+ |
| } |
| ) => { |
| #[inline] |
| $proj_vis fn $method_ident<'__pin>( |
| self: $crate::__private::Pin<&'__pin $($mut)? Self>, |
| ) -> $proj_ty_ident <'__pin, $($ty_generics)*> { |
| unsafe { |
| match self.$get_method() { |
| $( |
| Self::$variant $({ |
| $($field),+ |
| })? => { |
| $proj_ty_ident::$variant $({ |
| $( |
| $field: $crate::__pin_project_make_unsafe_field_proj!( |
| $(#[$pin])? $field |
| ) |
| ),+ |
| })? |
| } |
| ),+ |
| } |
| } |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_enum_make_proj_replace_method { |
| ([] $($field:tt)*) => {}; |
| ( |
| [$proj_ty_ident:ident] |
| [$proj_vis:vis] |
| [$($ty_generics:tt)*] |
| { |
| $( |
| $variant:ident $({ |
| $( |
| $(#[$pin:ident])? |
| $field:ident |
| ),+ |
| })? |
| ),+ |
| } |
| ) => { |
| #[inline] |
| $proj_vis fn project_replace( |
| self: $crate::__private::Pin<&mut Self>, |
| replacement: Self, |
| ) -> $proj_ty_ident <$($ty_generics)*> { |
| unsafe { |
| let __self_ptr: *mut Self = self.get_unchecked_mut(); |
| |
| // Destructors will run in reverse order, so next create a guard to overwrite |
| // `self` with the replacement value without calling destructors. |
| let __guard = $crate::__private::UnsafeOverwriteGuard::new(__self_ptr, replacement); |
| |
| match &mut *__self_ptr { |
| $( |
| Self::$variant $({ |
| $($field),+ |
| })? => { |
| $crate::__pin_project_make_proj_replace_block! { |
| [$proj_ty_ident :: $variant] |
| $({ |
| $( |
| $(#[$pin])? |
| $field |
| ),+ |
| })? |
| } |
| } |
| ),+ |
| } |
| } |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_unpin_impl { |
| ( |
| [$vis:vis $ident:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| $($field:tt)* |
| ) => { |
| // Automatically create the appropriate conditional `Unpin` implementation. |
| // |
| // Basically this is equivalent to the following code: |
| // ```rust |
| // impl<T, U> Unpin for Struct<T, U> where T: Unpin {} |
| // ``` |
| // |
| // However, if struct is public and there is a private type field, |
| // this would cause an E0446 (private type in public interface). |
| // |
| // When RFC 2145 is implemented (rust-lang/rust#48054), |
| // this will become a lint, rather then a hard error. |
| // |
| // As a workaround for this, we generate a new struct, containing all of the pinned |
| // fields from our #[pin_project] type. This struct is declared within |
| // a function, which makes it impossible to be named by user code. |
| // This guarantees that it will use the default auto-trait impl for Unpin - |
| // that is, it will implement Unpin iff all of its fields implement Unpin. |
| // This type can be safely declared as 'public', satisfying the privacy |
| // checker without actually allowing user code to access it. |
| // |
| // This allows users to apply the #[pin_project] attribute to types |
| // regardless of the privacy of the types of their fields. |
| // |
| // See also https://github.com/taiki-e/pin-project/pull/53. |
| #[allow(non_snake_case)] |
| $vis struct __Origin <'__pin, $($impl_generics)*> |
| $(where |
| $($where_clause)*)? |
| { |
| __dummy_lifetime: $crate::__private::PhantomData<&'__pin ()>, |
| $($field)* |
| } |
| impl <'__pin, $($impl_generics)*> $crate::__private::Unpin for $ident <$($ty_generics)*> |
| where |
| __Origin <'__pin, $($ty_generics)*>: $crate::__private::Unpin |
| $(, $($where_clause)*)? |
| { |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_drop_impl { |
| ( |
| [$_ident:ident] |
| [$($_impl_generics:tt)*] [$($_ty_generics:tt)*] [$(where $($_where_clause:tt)*)?] |
| impl $(< |
| $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)? |
| $( $generics:ident |
| $(: $generics_bound:path)? |
| $(: ?$generics_unsized_bound:path)? |
| $(: $generics_lifetime_bound:lifetime)? |
| ),* |
| >)? PinnedDrop for $self_ty:ty |
| $(where |
| $( $where_clause_ty:ty |
| $(: $where_clause_bound:path)? |
| $(: ?$where_clause_unsized_bound:path)? |
| $(: $where_clause_lifetime_bound:lifetime)? |
| ),* $(,)? |
| )? |
| { |
| fn drop($($arg:ident)+: Pin<&mut Self>) { |
| $($tt:tt)* |
| } |
| } |
| ) => { |
| impl $(< |
| $( $lifetime $(: $lifetime_bound)? ,)* |
| $( $generics |
| $(: $generics_bound)? |
| $(: ?$generics_unsized_bound)? |
| $(: $generics_lifetime_bound)? |
| ),* |
| >)? $crate::__private::Drop for $self_ty |
| $(where |
| $( $where_clause_ty |
| $(: $where_clause_bound)? |
| $(: ?$where_clause_unsized_bound)? |
| $(: $where_clause_lifetime_bound)? |
| ),* |
| )? |
| { |
| fn drop(&mut self) { |
| // Implementing `__DropInner::__drop_inner` 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](https://github.com/rust-lang/rust/pull/62360). |
| // |
| // `__drop_inner` is defined as a safe method, but this is fine since |
| // `__drop_inner` is not accessible by the users and we call `__drop_inner` only |
| // once. |
| // |
| // Users can implement [`Drop`] safely using `pin_project!` and can drop a |
| // type that implements `PinnedDrop` using the [`drop`] function safely. |
| fn __drop_inner $(< |
| $( $lifetime $(: $lifetime_bound)? ,)* |
| $( $generics |
| $(: $generics_bound)? |
| $(: ?$generics_unsized_bound)? |
| $(: $generics_lifetime_bound)? |
| ),* |
| >)? ( |
| $($arg)+: $crate::__private::Pin<&mut $self_ty>, |
| ) |
| $(where |
| $( $where_clause_ty |
| $(: $where_clause_bound)? |
| $(: ?$where_clause_unsized_bound)? |
| $(: $where_clause_lifetime_bound)? |
| ),* |
| )? |
| { |
| // A dummy `__drop_inner` function to prevent users call outer `__drop_inner`. |
| fn __drop_inner() {} |
| $($tt)* |
| } |
| |
| // Safety - we're in 'drop', so we know that 'self' will |
| // never move again. |
| let pinned_self: $crate::__private::Pin<&mut Self> |
| = unsafe { $crate::__private::Pin::new_unchecked(self) }; |
| // We call `__drop_inner` only once. Since `__DropInner::__drop_inner` |
| // is not accessible by the users, it is never called again. |
| __drop_inner(pinned_self); |
| } |
| } |
| }; |
| ( |
| [$ident:ident] |
| [$($impl_generics:tt)*] [$($ty_generics:tt)*] [$(where $($where_clause:tt)*)?] |
| ) => { |
| // Ensure that struct does not implement `Drop`. |
| // |
| // There are two possible cases: |
| // 1. The user type does not implement Drop. In this case, |
| // the first blanked impl will not apply to it. This code |
| // will compile, as there is only one impl of MustNotImplDrop for the user type |
| // 2. The user type does impl Drop. This will make the blanket impl applicable, |
| // which will then conflict with the explicit MustNotImplDrop impl below. |
| // This will result in a compilation error, which is exactly what we want. |
| trait MustNotImplDrop {} |
| #[allow(clippy::drop_bounds, drop_bounds)] |
| impl<T: $crate::__private::Drop> MustNotImplDrop for T {} |
| impl <$($impl_generics)*> MustNotImplDrop for $ident <$($ty_generics)*> |
| $(where |
| $($where_clause)*)? |
| { |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_unpin_bound { |
| (#[pin] $field_ty:ty) => { |
| $field_ty |
| }; |
| ($field_ty:ty) => { |
| $crate::__private::AlwaysUnpin<$field_ty> |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_unsafe_field_proj { |
| (#[pin] $field:ident) => { |
| $crate::__private::Pin::new_unchecked($field) |
| }; |
| ($field:ident) => { |
| $field |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_replace_field_proj { |
| (#[pin] $field:ident) => { |
| $crate::__private::PhantomData |
| }; |
| ($field:ident) => { |
| $crate::__private::ptr::read($field) |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_unsafe_drop_in_place_guard { |
| (#[pin] $field:ident) => { |
| $crate::__private::UnsafeDropInPlaceGuard::new($field) |
| }; |
| ($field:ident) => { |
| () |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_field_mut { |
| (#[pin] $field_ty:ty) => { |
| $crate::__private::Pin<&'__pin mut ($field_ty)> |
| }; |
| ($field_ty:ty) => { |
| &'__pin mut ($field_ty) |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_field_ref { |
| (#[pin] $field_ty:ty) => { |
| $crate::__private::Pin<&'__pin ($field_ty)> |
| }; |
| ($field_ty:ty) => { |
| &'__pin ($field_ty) |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_make_proj_field_replace { |
| (#[pin] $field_ty:ty) => { |
| $crate::__private::PhantomData<$field_ty> |
| }; |
| ($field_ty:ty) => { |
| $field_ty |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_internal { |
| // parsing proj_mut_ident |
| ( |
| [] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| |
| #[project = $proj_mut_ident:ident] |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_internal! { |
| [$proj_mut_ident] |
| [$($proj_ref_ident)?] |
| [$($proj_replace_ident)?] |
| [$($attrs)*] |
| $($tt)* |
| } |
| }; |
| // parsing proj_ref_ident |
| ( |
| [$($proj_mut_ident:ident)?] |
| [] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| |
| #[project_ref = $proj_ref_ident:ident] |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_internal! { |
| [$($proj_mut_ident)?] |
| [$proj_ref_ident] |
| [$($proj_replace_ident)?] |
| [$($attrs)*] |
| $($tt)* |
| } |
| }; |
| // parsing proj_replace_ident |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [] |
| [$($attrs:tt)*] |
| |
| #[project_replace = $proj_replace_ident:ident] |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_internal! { |
| [$($proj_mut_ident)?] |
| [$($proj_ref_ident)?] |
| [$proj_replace_ident] |
| [$($attrs)*] |
| $($tt)* |
| } |
| }; |
| // this is actually part of a recursive step that picks off a single non-`pin_project_lite` attribute |
| // there could be more to parse |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| |
| #[$($attr:tt)*] |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_internal! { |
| [$($proj_mut_ident)?] |
| [$($proj_ref_ident)?] |
| [$($proj_replace_ident)?] |
| [$($attrs)* #[$($attr)*]] |
| $($tt)* |
| } |
| }; |
| // now determine visibility |
| // if public, downgrade |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| pub $struct_ty_ident:ident $ident:ident |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_parse_generics! { |
| [$($proj_mut_ident)?] |
| [$($proj_ref_ident)?] |
| [$($proj_replace_ident)?] |
| [$($attrs)*] |
| [pub $struct_ty_ident $ident pub(crate)] |
| $($tt)* |
| } |
| }; |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| $vis:vis $struct_ty_ident:ident $ident:ident |
| $($tt:tt)* |
| ) => { |
| $crate::__pin_project_parse_generics! { |
| [$($proj_mut_ident)?] |
| [$($proj_ref_ident)?] |
| [$($proj_replace_ident)?] |
| [$($attrs)*] |
| [$vis $struct_ty_ident $ident $vis] |
| $($tt)* |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| #[macro_export] |
| macro_rules! __pin_project_parse_generics { |
| ( |
| [$($proj_mut_ident:ident)?] |
| [$($proj_ref_ident:ident)?] |
| [$($proj_replace_ident:ident)?] |
| [$($attrs:tt)*] |
| [$vis:vis $struct_ty_ident:ident $ident:ident $proj_ty_vis:vis] |
| $(< |
| $( $lifetime:lifetime $(: $lifetime_bound:lifetime)? ),* $(,)? |
| $( $generics:ident |
| $(: $generics_bound:path)? |
| $(: ?$generics_unsized_bound:path)? |
| $(: $generics_lifetime_bound:lifetime)? |
| $(= $generics_default:ty)? |
| ),* $(,)? |
| >)? |
| $(where |
| $( $where_clause_ty:ty |
| $(: $where_clause_bound:path)? |
| $(: ?$where_clause_unsized_bound:path)? |
| $(: $where_clause_lifetime_bound:lifetime)? |
| ),* $(,)? |
| )? |
| { |
| $($body_data:tt)* |
| } |
| $(impl $($pinned_drop:tt)*)? |
| ) => { |
| $crate::__pin_project_expand! { |
| [$($proj_mut_ident)?] |
| [$($proj_ref_ident)?] |
| [$($proj_replace_ident)?] |
| [$proj_ty_vis] |
| [$($attrs)* $vis $struct_ty_ident $ident] |
| [$(< |
| $( $lifetime $(: $lifetime_bound)? ,)* |
| $( $generics |
| $(: $generics_bound)? |
| $(: ?$generics_unsized_bound)? |
| $(: $generics_lifetime_bound)? |
| $(= $generics_default)? |
| ),* |
| >)?] |
| [$( |
| $( $lifetime $(: $lifetime_bound)? ,)* |
| $( $generics |
| $(: $generics_bound)? |
| $(: ?$generics_unsized_bound)? |
| $(: $generics_lifetime_bound)? |
| ),* |
| )?] |
| [$( $( $lifetime ,)* $( $generics ),* )?] |
| [$(where $( $where_clause_ty |
| $(: $where_clause_bound)? |
| $(: ?$where_clause_unsized_bound)? |
| $(: $where_clause_lifetime_bound)? |
| ),* )?] |
| { |
| $($body_data)* |
| } |
| $(impl $($pinned_drop)*)? |
| } |
| }; |
| } |
| |
| #[doc(hidden)] |
| pub mod __private { |
| use core::mem::ManuallyDrop; |
| #[doc(hidden)] |
| pub use core::{ |
| marker::{PhantomData, Unpin}, |
| ops::Drop, |
| pin::Pin, |
| ptr, |
| }; |
| |
| // This is an internal helper struct used by `pin_project!`. |
| #[doc(hidden)] |
| pub struct AlwaysUnpin<T: ?Sized>(PhantomData<T>); |
| |
| impl<T: ?Sized> Unpin for AlwaysUnpin<T> {} |
| |
| // This is an internal helper used to ensure a value is dropped. |
| #[doc(hidden)] |
| pub struct UnsafeDropInPlaceGuard<T: ?Sized>(*mut T); |
| |
| impl<T: ?Sized> UnsafeDropInPlaceGuard<T> { |
| #[doc(hidden)] |
| pub unsafe fn new(ptr: *mut T) -> Self { |
| Self(ptr) |
| } |
| } |
| |
| impl<T: ?Sized> Drop for UnsafeDropInPlaceGuard<T> { |
| fn drop(&mut self) { |
| // SAFETY: the caller of `UnsafeDropInPlaceGuard::new` must guarantee |
| // that `ptr` is valid for drop when this guard is destructed. |
| unsafe { |
| ptr::drop_in_place(self.0); |
| } |
| } |
| } |
| |
| // This is an internal helper used to ensure a value is overwritten without |
| // its destructor being called. |
| #[doc(hidden)] |
| pub struct UnsafeOverwriteGuard<T> { |
| target: *mut T, |
| value: ManuallyDrop<T>, |
| } |
| |
| impl<T> UnsafeOverwriteGuard<T> { |
| #[doc(hidden)] |
| pub unsafe fn new(target: *mut T, value: T) -> Self { |
| Self { target, value: ManuallyDrop::new(value) } |
| } |
| } |
| |
| impl<T> Drop for UnsafeOverwriteGuard<T> { |
| fn drop(&mut self) { |
| // SAFETY: the caller of `UnsafeOverwriteGuard::new` must guarantee |
| // that `target` is valid for writes when this guard is destructed. |
| unsafe { |
| ptr::write(self.target, ptr::read(&*self.value)); |
| } |
| } |
| } |
| } |
