| // Copyright 2019 The Fuchsia Authors |
| // |
| // Licensed under a BSD-style license <LICENSE-BSD>, Apache License, Version 2.0 |
| // <LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0>, or the MIT |
| // license <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your option. |
| // This file may not be copied, modified, or distributed except according to |
| // those terms. |
| |
| use core::{ |
| convert::{Infallible, TryFrom}, |
| num::NonZeroU32, |
| }; |
| |
| use proc_macro2::{Span, TokenStream}; |
| use quote::{quote_spanned, ToTokens, TokenStreamExt as _}; |
| use syn::{ |
| punctuated::Punctuated, spanned::Spanned as _, token::Comma, Attribute, Error, LitInt, Meta, |
| MetaList, |
| }; |
| |
| /// The computed representation of a type. |
| /// |
| /// This is the result of processing all `#[repr(...)]` attributes on a type, if |
| /// any. A `Repr` is only capable of representing legal combinations of |
| /// `#[repr(...)]` attributes. |
| #[cfg_attr(test, derive(Copy, Clone, Debug))] |
| pub(crate) enum Repr<Prim, Packed> { |
| /// `#[repr(transparent)]` |
| Transparent(Span), |
| /// A compound representation: `repr(C)`, `repr(Rust)`, or `repr(Int)` |
| /// optionally combined with `repr(packed(...))` or `repr(align(...))` |
| Compound(Spanned<CompoundRepr<Prim>>, Option<Spanned<AlignRepr<Packed>>>), |
| } |
| |
| /// A compound representation: `repr(C)`, `repr(Rust)`, or `repr(Int)`. |
| #[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] |
| pub(crate) enum CompoundRepr<Prim> { |
| C, |
| Rust, |
| Primitive(Prim), |
| } |
| |
| /// `repr(Int)` |
| #[derive(Copy, Clone)] |
| #[cfg_attr(test, derive(Debug, Eq, PartialEq))] |
| pub(crate) enum PrimitiveRepr { |
| U8, |
| U16, |
| U32, |
| U64, |
| Usize, |
| I8, |
| I16, |
| I32, |
| I64, |
| Isize, |
| } |
| |
| /// `repr(packed(...))` or `repr(align(...))` |
| #[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] |
| pub(crate) enum AlignRepr<Packed> { |
| Packed(Packed), |
| Align(NonZeroU32), |
| } |
| |
| /// The representations which can legally appear on a struct or union type. |
| pub(crate) type StructUnionRepr = Repr<Infallible, NonZeroU32>; |
| |
| /// The representations which can legally appear on an enum type. |
| pub(crate) type EnumRepr = Repr<PrimitiveRepr, Infallible>; |
| |
| impl<Prim, Packed> Repr<Prim, Packed> { |
| /// Gets the name of this "repr type" - the non-align `repr(X)` that is used |
| /// in prose to refer to this type. |
| /// |
| /// For example, we would refer to `#[repr(C, align(4))] struct Foo { ... }` |
| /// as a "`repr(C)` struct". |
| pub(crate) fn repr_type_name(&self) -> &str |
| where |
| Prim: Copy + With<PrimitiveRepr>, |
| { |
| use {CompoundRepr::*, PrimitiveRepr::*, Repr::*}; |
| match self { |
| Transparent(_span) => "repr(transparent)", |
| Compound(Spanned { t: repr, span: _ }, _align) => match repr { |
| C => "repr(C)", |
| Rust => "repr(Rust)", |
| Primitive(prim) => prim.with(|prim| match prim { |
| U8 => "repr(u8)", |
| U16 => "repr(u16)", |
| U32 => "repr(u32)", |
| U64 => "repr(u64)", |
| Usize => "repr(usize)", |
| I8 => "repr(i8)", |
| I16 => "repr(i16)", |
| I32 => "repr(i32)", |
| I64 => "repr(i64)", |
| Isize => "repr(isize)", |
| }), |
| }, |
| } |
| } |
| |
| pub(crate) fn is_transparent(&self) -> bool { |
| matches!(self, Repr::Transparent(_)) |
| } |
| |
| pub(crate) fn is_c(&self) -> bool { |
| use CompoundRepr::*; |
| matches!(self, Repr::Compound(Spanned { t: C, span: _ }, _align)) |
| } |
| |
| pub(crate) fn is_primitive(&self) -> bool { |
| use CompoundRepr::*; |
| matches!(self, Repr::Compound(Spanned { t: Primitive(_), span: _ }, _align)) |
| } |
| |
| pub(crate) fn get_packed(&self) -> Option<&Packed> { |
| use {AlignRepr::*, Repr::*}; |
| if let Compound(_, Some(Spanned { t: Packed(p), span: _ })) = self { |
| Some(p) |
| } else { |
| None |
| } |
| } |
| |
| pub(crate) fn get_align(&self) -> Option<Spanned<NonZeroU32>> { |
| use {AlignRepr::*, Repr::*}; |
| if let Compound(_, Some(Spanned { t: Align(n), span })) = self { |
| Some(Spanned::new(*n, *span)) |
| } else { |
| None |
| } |
| } |
| |
| pub(crate) fn is_align_gt_1(&self) -> bool { |
| self.get_align().map(|n| n.t.get() > 1).unwrap_or(false) |
| } |
| |
| /// When deriving `Unaligned`, validate that the decorated type has no |
| /// `#[repr(align(N))]` attribute where `N > 1`. If no such attribute exists |
| /// (including if `N == 1`), this returns `Ok(())`, and otherwise it returns |
| /// a descriptive error. |
| pub(crate) fn unaligned_validate_no_align_gt_1(&self) -> Result<(), Error> { |
| if let Some(n) = self.get_align().filter(|n| n.t.get() > 1) { |
| Err(Error::new( |
| n.span, |
| "cannot derive `Unaligned` on type with alignment greater than 1", |
| )) |
| } else { |
| Ok(()) |
| } |
| } |
| } |
| |
| impl<Prim> Repr<Prim, NonZeroU32> { |
| /// Does `self` describe a `#[repr(packed)]` or `#[repr(packed(1))]` type? |
| pub(crate) fn is_packed_1(&self) -> bool { |
| self.get_packed().map(|n| n.get() == 1).unwrap_or(false) |
| } |
| } |
| |
| impl<Packed> Repr<PrimitiveRepr, Packed> { |
| fn get_primitive(&self) -> Option<&PrimitiveRepr> { |
| use {CompoundRepr::*, Repr::*}; |
| if let Compound(Spanned { t: Primitive(p), span: _ }, _align) = self { |
| Some(p) |
| } else { |
| None |
| } |
| } |
| |
| /// Does `self` describe a `#[repr(u8)]` type? |
| pub(crate) fn is_u8(&self) -> bool { |
| matches!(self.get_primitive(), Some(PrimitiveRepr::U8)) |
| } |
| |
| /// Does `self` describe a `#[repr(i8)]` type? |
| pub(crate) fn is_i8(&self) -> bool { |
| matches!(self.get_primitive(), Some(PrimitiveRepr::I8)) |
| } |
| } |
| |
| impl<Prim, Packed> ToTokens for Repr<Prim, Packed> |
| where |
| Prim: With<PrimitiveRepr> + Copy, |
| Packed: With<NonZeroU32> + Copy, |
| { |
| fn to_tokens(&self, ts: &mut TokenStream) { |
| use Repr::*; |
| match self { |
| Transparent(span) => ts.append_all(quote_spanned! { *span=> #[repr(transparent)] }), |
| Compound(repr, align) => { |
| repr.to_tokens(ts); |
| if let Some(align) = align { |
| align.to_tokens(ts); |
| } |
| } |
| } |
| } |
| } |
| |
| impl<Prim: With<PrimitiveRepr> + Copy> ToTokens for Spanned<CompoundRepr<Prim>> { |
| fn to_tokens(&self, ts: &mut TokenStream) { |
| use CompoundRepr::*; |
| match &self.t { |
| C => ts.append_all(quote_spanned! { self.span=> #[repr(C)] }), |
| Rust => ts.append_all(quote_spanned! { self.span=> #[repr(Rust)] }), |
| Primitive(prim) => prim.with(|prim| Spanned::new(prim, self.span).to_tokens(ts)), |
| } |
| } |
| } |
| |
| impl ToTokens for Spanned<PrimitiveRepr> { |
| fn to_tokens(&self, ts: &mut TokenStream) { |
| use PrimitiveRepr::*; |
| match self.t { |
| U8 => ts.append_all(quote_spanned! { self.span => #[repr(u8)] }), |
| U16 => ts.append_all(quote_spanned! { self.span => #[repr(u16)] }), |
| U32 => ts.append_all(quote_spanned! { self.span => #[repr(u32)] }), |
| U64 => ts.append_all(quote_spanned! { self.span => #[repr(u64)] }), |
| Usize => ts.append_all(quote_spanned! { self.span => #[repr(usize)] }), |
| I8 => ts.append_all(quote_spanned! { self.span => #[repr(i8)] }), |
| I16 => ts.append_all(quote_spanned! { self.span => #[repr(i16)] }), |
| I32 => ts.append_all(quote_spanned! { self.span => #[repr(i32)] }), |
| I64 => ts.append_all(quote_spanned! { self.span => #[repr(i64)] }), |
| Isize => ts.append_all(quote_spanned! { self.span => #[repr(isize)] }), |
| } |
| } |
| } |
| |
| impl<Packed: With<NonZeroU32> + Copy> ToTokens for Spanned<AlignRepr<Packed>> { |
| fn to_tokens(&self, ts: &mut TokenStream) { |
| use AlignRepr::*; |
| // We use `syn::Index` instead of `u32` because `quote_spanned!` |
| // serializes `u32` literals as `123u32`, not just `123`. Rust doesn't |
| // recognize that as a valid argument to `#[repr(align(...))]` or |
| // `#[repr(packed(...))]`. |
| let to_index = |n: NonZeroU32| syn::Index { index: n.get(), span: self.span }; |
| match self.t { |
| Packed(n) => n.with(|n| { |
| let n = to_index(n); |
| ts.append_all(quote_spanned! { self.span => #[repr(packed(#n))] }) |
| }), |
| Align(n) => { |
| let n = to_index(n); |
| ts.append_all(quote_spanned! { self.span => #[repr(align(#n))] }) |
| } |
| } |
| } |
| } |
| |
| /// The result of parsing a single `#[repr(...)]` attribute or a single |
| /// directive inside a compound `#[repr(..., ...)]` attribute. |
| #[derive(Copy, Clone, PartialEq, Eq)] |
| #[cfg_attr(test, derive(Debug))] |
| pub(crate) enum RawRepr { |
| Transparent, |
| C, |
| Rust, |
| U8, |
| U16, |
| U32, |
| U64, |
| Usize, |
| I8, |
| I16, |
| I32, |
| I64, |
| Isize, |
| Align(NonZeroU32), |
| PackedN(NonZeroU32), |
| Packed, |
| } |
| |
| /// The error from converting from a `RawRepr`. |
| #[cfg_attr(test, derive(Debug, Eq, PartialEq))] |
| pub(crate) enum FromRawReprError<E> { |
| /// The `RawRepr` doesn't affect the high-level repr we're parsing (e.g. |
| /// it's `align(...)` and we're parsing a `CompoundRepr`). |
| None, |
| /// The `RawRepr` is invalid for the high-level repr we're parsing (e.g. |
| /// it's `packed` repr and we're parsing an `AlignRepr` for an enum type). |
| Err(E), |
| } |
| |
| /// The representation hint is not supported for the decorated type. |
| #[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] |
| pub(crate) struct UnsupportedReprError; |
| |
| impl<Prim: With<PrimitiveRepr>> TryFrom<RawRepr> for CompoundRepr<Prim> { |
| type Error = FromRawReprError<UnsupportedReprError>; |
| fn try_from( |
| raw: RawRepr, |
| ) -> Result<CompoundRepr<Prim>, FromRawReprError<UnsupportedReprError>> { |
| use RawRepr::*; |
| match raw { |
| C => Ok(CompoundRepr::C), |
| Rust => Ok(CompoundRepr::Rust), |
| raw @ (U8 | U16 | U32 | U64 | Usize | I8 | I16 | I32 | I64 | Isize) => { |
| Prim::try_with_or( |
| || match raw { |
| U8 => Ok(PrimitiveRepr::U8), |
| U16 => Ok(PrimitiveRepr::U16), |
| U32 => Ok(PrimitiveRepr::U32), |
| U64 => Ok(PrimitiveRepr::U64), |
| Usize => Ok(PrimitiveRepr::Usize), |
| I8 => Ok(PrimitiveRepr::I8), |
| I16 => Ok(PrimitiveRepr::I16), |
| I32 => Ok(PrimitiveRepr::I32), |
| I64 => Ok(PrimitiveRepr::I64), |
| Isize => Ok(PrimitiveRepr::Isize), |
| Transparent | C | Rust | Align(_) | PackedN(_) | Packed => { |
| Err(UnsupportedReprError) |
| } |
| }, |
| UnsupportedReprError, |
| ) |
| .map(CompoundRepr::Primitive) |
| .map_err(FromRawReprError::Err) |
| } |
| Transparent | Align(_) | PackedN(_) | Packed => Err(FromRawReprError::None), |
| } |
| } |
| } |
| |
| impl<Pcked: With<NonZeroU32>> TryFrom<RawRepr> for AlignRepr<Pcked> { |
| type Error = FromRawReprError<UnsupportedReprError>; |
| fn try_from(raw: RawRepr) -> Result<AlignRepr<Pcked>, FromRawReprError<UnsupportedReprError>> { |
| use RawRepr::*; |
| match raw { |
| Packed | PackedN(_) => Pcked::try_with_or( |
| || match raw { |
| Packed => Ok(NonZeroU32::new(1).unwrap()), |
| PackedN(n) => Ok(n), |
| U8 | U16 | U32 | U64 | Usize | I8 | I16 | I32 | I64 | Isize | Transparent |
| | C | Rust | Align(_) => Err(UnsupportedReprError), |
| }, |
| UnsupportedReprError, |
| ) |
| .map(AlignRepr::Packed) |
| .map_err(FromRawReprError::Err), |
| Align(n) => Ok(AlignRepr::Align(n)), |
| U8 | U16 | U32 | U64 | Usize | I8 | I16 | I32 | I64 | Isize | Transparent | C |
| | Rust => Err(FromRawReprError::None), |
| } |
| } |
| } |
| |
| /// The error from extracting a high-level repr type from a list of `RawRepr`s. |
| #[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] |
| enum FromRawReprsError<E> { |
| /// One of the `RawRepr`s is invalid for the high-level repr we're parsing |
| /// (e.g. there's a `packed` repr and we're parsing an `AlignRepr` for an |
| /// enum type). |
| Single(E), |
| /// Two `RawRepr`s appear which both affect the high-level repr we're |
| /// parsing (e.g., the list is `#[repr(align(2), packed)]`). Note that we |
| /// conservatively treat redundant reprs as conflicting (e.g. |
| /// `#[repr(packed, packed)]`). |
| Conflict, |
| } |
| |
| /// Tries to extract a high-level repr from a list of `RawRepr`s. |
| fn try_from_raw_reprs<'a, E, R: TryFrom<RawRepr, Error = FromRawReprError<E>>>( |
| r: impl IntoIterator<Item = &'a Spanned<RawRepr>>, |
| ) -> Result<Option<Spanned<R>>, Spanned<FromRawReprsError<E>>> { |
| // Walk the list of `RawRepr`s and attempt to convert each to an `R`. Bail |
| // if we find any errors. If we find more than one which converts to an `R`, |
| // bail with a `Conflict` error. |
| r.into_iter().try_fold(None, |found: Option<Spanned<R>>, raw| { |
| let new = match Spanned::<R>::try_from(*raw) { |
| Ok(r) => r, |
| // This `RawRepr` doesn't convert to an `R`, so keep the current |
| // found `R`, if any. |
| Err(FromRawReprError::None) => return Ok(found), |
| // This repr is unsupported for the decorated type (e.g. |
| // `repr(packed)` on an enum). |
| Err(FromRawReprError::Err(Spanned { t: err, span })) => { |
| return Err(Spanned::new(FromRawReprsError::Single(err), span)) |
| } |
| }; |
| |
| if let Some(found) = found { |
| // We already found an `R`, but this `RawRepr` also converts to an |
| // `R`, so that's a conflict. |
| // |
| // `Span::join` returns `None` if the two spans are from different |
| // files or if we're not on the nightly compiler. In that case, just |
| // use `new`'s span. |
| let span = found.span.join(new.span).unwrap_or(new.span); |
| Err(Spanned::new(FromRawReprsError::Conflict, span)) |
| } else { |
| Ok(Some(new)) |
| } |
| }) |
| } |
| |
| /// The error returned from [`Repr::from_attrs`]. |
| #[cfg_attr(test, derive(Copy, Clone, Debug, Eq, PartialEq))] |
| enum FromAttrsError { |
| FromRawReprs(FromRawReprsError<UnsupportedReprError>), |
| Unrecognized, |
| } |
| |
| impl From<FromRawReprsError<UnsupportedReprError>> for FromAttrsError { |
| fn from(err: FromRawReprsError<UnsupportedReprError>) -> FromAttrsError { |
| FromAttrsError::FromRawReprs(err) |
| } |
| } |
| |
| impl From<UnrecognizedReprError> for FromAttrsError { |
| fn from(_err: UnrecognizedReprError) -> FromAttrsError { |
| FromAttrsError::Unrecognized |
| } |
| } |
| |
| impl From<Spanned<FromAttrsError>> for Error { |
| fn from(err: Spanned<FromAttrsError>) -> Error { |
| let Spanned { t: err, span } = err; |
| match err { |
| FromAttrsError::FromRawReprs(FromRawReprsError::Single( |
| _err @ UnsupportedReprError, |
| )) => Error::new(span, "unsupported representation hint for the decorated type"), |
| FromAttrsError::FromRawReprs(FromRawReprsError::Conflict) => { |
| // NOTE: This says "another" rather than "a preceding" because |
| // when one of the reprs involved is `transparent`, we detect |
| // that condition in `Repr::from_attrs`, and at that point we |
| // can't tell which repr came first, so we might report this on |
| // the first involved repr rather than the second, third, etc. |
| Error::new(span, "this conflicts with another representation hint") |
| } |
| FromAttrsError::Unrecognized => Error::new(span, "unrecognized representation hint"), |
| } |
| } |
| } |
| |
| impl<Prim, Packed> Repr<Prim, Packed> { |
| fn from_attrs_inner(attrs: &[Attribute]) -> Result<Repr<Prim, Packed>, Spanned<FromAttrsError>> |
| where |
| Prim: With<PrimitiveRepr>, |
| Packed: With<NonZeroU32>, |
| { |
| let raw_reprs = RawRepr::from_attrs(attrs).map_err(Spanned::from)?; |
| |
| let transparent = { |
| let mut transparents = raw_reprs.iter().filter_map(|Spanned { t, span }| match t { |
| RawRepr::Transparent => Some(span), |
| _ => None, |
| }); |
| let first = transparents.next(); |
| let second = transparents.next(); |
| match (first, second) { |
| (None, None) => None, |
| (Some(span), None) => Some(*span), |
| (Some(_), Some(second)) => { |
| return Err(Spanned::new( |
| FromAttrsError::FromRawReprs(FromRawReprsError::Conflict), |
| *second, |
| )) |
| } |
| // An iterator can't produce a value only on the second call to |
| // `.next()`. |
| (None, Some(_)) => unreachable!(), |
| } |
| }; |
| |
| let compound: Option<Spanned<CompoundRepr<Prim>>> = |
| try_from_raw_reprs(raw_reprs.iter()).map_err(Spanned::from)?; |
| let align: Option<Spanned<AlignRepr<Packed>>> = |
| try_from_raw_reprs(raw_reprs.iter()).map_err(Spanned::from)?; |
| |
| if let Some(span) = transparent { |
| if compound.is_some() || align.is_some() { |
| // Arbitrarily report the problem on the `transparent` span. Any |
| // span will do. |
| return Err(Spanned::new(FromRawReprsError::Conflict.into(), span)); |
| } |
| |
| Ok(Repr::Transparent(span)) |
| } else { |
| Ok(Repr::Compound( |
| compound.unwrap_or(Spanned::new(CompoundRepr::Rust, Span::call_site())), |
| align, |
| )) |
| } |
| } |
| } |
| |
| impl<Prim, Packed> Repr<Prim, Packed> { |
| pub(crate) fn from_attrs(attrs: &[Attribute]) -> Result<Repr<Prim, Packed>, Error> |
| where |
| Prim: With<PrimitiveRepr>, |
| Packed: With<NonZeroU32>, |
| { |
| Repr::from_attrs_inner(attrs).map_err(Into::into) |
| } |
| } |
| |
| /// The representation hint could not be parsed or was unrecognized. |
| struct UnrecognizedReprError; |
| |
| impl RawRepr { |
| fn from_attrs( |
| attrs: &[Attribute], |
| ) -> Result<Vec<Spanned<RawRepr>>, Spanned<UnrecognizedReprError>> { |
| let mut reprs = Vec::new(); |
| for attr in attrs { |
| // Ignore documentation attributes. |
| if attr.path().is_ident("doc") { |
| continue; |
| } |
| if let Meta::List(ref meta_list) = attr.meta { |
| if meta_list.path.is_ident("repr") { |
| let parsed: Punctuated<Meta, Comma> = |
| match meta_list.parse_args_with(Punctuated::parse_terminated) { |
| Ok(parsed) => parsed, |
| Err(_) => { |
| return Err(Spanned::new( |
| UnrecognizedReprError, |
| meta_list.tokens.span(), |
| )) |
| } |
| }; |
| for meta in parsed { |
| let s = meta.span(); |
| reprs.push( |
| RawRepr::from_meta(&meta) |
| .map(|r| Spanned::new(r, s)) |
| .map_err(|e| Spanned::new(e, s))?, |
| ); |
| } |
| } |
| } |
| } |
| |
| Ok(reprs) |
| } |
| |
| fn from_meta(meta: &Meta) -> Result<RawRepr, UnrecognizedReprError> { |
| let (path, list) = match meta { |
| Meta::Path(path) => (path, None), |
| Meta::List(list) => (&list.path, Some(list)), |
| _ => return Err(UnrecognizedReprError), |
| }; |
| |
| let ident = path.get_ident().ok_or(UnrecognizedReprError)?; |
| |
| // Only returns `Ok` for non-zero power-of-two values. |
| let parse_nzu64 = |list: &MetaList| { |
| list.parse_args::<LitInt>() |
| .and_then(|int| int.base10_parse::<NonZeroU32>()) |
| .map_err(|_| UnrecognizedReprError) |
| .and_then(|nz| { |
| if nz.get().is_power_of_two() { |
| Ok(nz) |
| } else { |
| Err(UnrecognizedReprError) |
| } |
| }) |
| }; |
| |
| use RawRepr::*; |
| Ok(match (ident.to_string().as_str(), list) { |
| ("u8", None) => U8, |
| ("u16", None) => U16, |
| ("u32", None) => U32, |
| ("u64", None) => U64, |
| ("usize", None) => Usize, |
| ("i8", None) => I8, |
| ("i16", None) => I16, |
| ("i32", None) => I32, |
| ("i64", None) => I64, |
| ("isize", None) => Isize, |
| ("C", None) => C, |
| ("transparent", None) => Transparent, |
| ("Rust", None) => Rust, |
| ("packed", None) => Packed, |
| ("packed", Some(list)) => PackedN(parse_nzu64(list)?), |
| ("align", Some(list)) => Align(parse_nzu64(list)?), |
| _ => return Err(UnrecognizedReprError), |
| }) |
| } |
| } |
| |
| pub(crate) use util::*; |
| mod util { |
| use super::*; |
| /// A value with an associated span. |
| #[derive(Copy, Clone)] |
| #[cfg_attr(test, derive(Debug))] |
| pub(crate) struct Spanned<T> { |
| pub(crate) t: T, |
| pub(crate) span: Span, |
| } |
| |
| impl<T> Spanned<T> { |
| pub(super) fn new(t: T, span: Span) -> Spanned<T> { |
| Spanned { t, span } |
| } |
| |
| pub(super) fn from<U>(s: Spanned<U>) -> Spanned<T> |
| where |
| T: From<U>, |
| { |
| let Spanned { t: u, span } = s; |
| Spanned::new(u.into(), span) |
| } |
| |
| /// Delegates to `T: TryFrom`, preserving span information in both the |
| /// success and error cases. |
| pub(super) fn try_from<E, U>( |
| u: Spanned<U>, |
| ) -> Result<Spanned<T>, FromRawReprError<Spanned<E>>> |
| where |
| T: TryFrom<U, Error = FromRawReprError<E>>, |
| { |
| let Spanned { t: u, span } = u; |
| T::try_from(u).map(|t| Spanned { t, span }).map_err(|err| match err { |
| FromRawReprError::None => FromRawReprError::None, |
| FromRawReprError::Err(e) => FromRawReprError::Err(Spanned::new(e, span)), |
| }) |
| } |
| } |
| |
| // Used to permit implementing `With<T> for T: Inhabited` and for |
| // `Infallible` without a blanket impl conflict. |
| pub(crate) trait Inhabited {} |
| impl Inhabited for PrimitiveRepr {} |
| impl Inhabited for NonZeroU32 {} |
| |
| pub(crate) trait With<T> { |
| fn with<O, F: FnOnce(T) -> O>(self, f: F) -> O; |
| fn try_with_or<E, F: FnOnce() -> Result<T, E>>(f: F, err: E) -> Result<Self, E> |
| where |
| Self: Sized; |
| } |
| |
| impl<T: Inhabited> With<T> for T { |
| fn with<O, F: FnOnce(T) -> O>(self, f: F) -> O { |
| f(self) |
| } |
| |
| fn try_with_or<E, F: FnOnce() -> Result<T, E>>(f: F, _err: E) -> Result<Self, E> { |
| f() |
| } |
| } |
| |
| impl<T> With<T> for Infallible { |
| fn with<O, F: FnOnce(T) -> O>(self, _f: F) -> O { |
| match self {} |
| } |
| |
| fn try_with_or<E, F: FnOnce() -> Result<T, E>>(_f: F, err: E) -> Result<Self, E> { |
| Err(err) |
| } |
| } |
| } |
| |
| #[cfg(test)] |
| mod tests { |
| use super::*; |
| use syn::parse_quote; |
| |
| impl<T> From<T> for Spanned<T> { |
| fn from(t: T) -> Spanned<T> { |
| Spanned::new(t, Span::call_site()) |
| } |
| } |
| |
| // We ignore spans for equality in testing since real spans are hard to |
| // synthesize and don't implement `PartialEq`. |
| impl<T: PartialEq> PartialEq for Spanned<T> { |
| fn eq(&self, other: &Spanned<T>) -> bool { |
| self.t.eq(&other.t) |
| } |
| } |
| |
| impl<T: Eq> Eq for Spanned<T> {} |
| |
| impl<Prim: PartialEq, Packed: PartialEq> PartialEq for Repr<Prim, Packed> { |
| fn eq(&self, other: &Repr<Prim, Packed>) -> bool { |
| match (self, other) { |
| (Repr::Transparent(_), Repr::Transparent(_)) => true, |
| (Repr::Compound(sc, sa), Repr::Compound(oc, oa)) => (sc, sa) == (oc, oa), |
| _ => false, |
| } |
| } |
| } |
| |
| fn s() -> Span { |
| Span::call_site() |
| } |
| |
| #[test] |
| fn test() { |
| // Test that a given `#[repr(...)]` attribute parses and returns the |
| // given `Repr` or error. |
| macro_rules! test { |
| ($(#[$attr:meta])* => $repr:expr) => { |
| test!(@inner $(#[$attr])* => Repr => Ok($repr)); |
| }; |
| // In the error case, the caller must explicitly provide the name of |
| // the `Repr` type to assist in type inference. |
| (@error $(#[$attr:meta])* => $typ:ident => $repr:expr) => { |
| test!(@inner $(#[$attr])* => $typ => Err($repr)); |
| }; |
| (@inner $(#[$attr:meta])* => $typ:ident => $repr:expr) => { |
| let attr: Attribute = parse_quote!($(#[$attr])*); |
| let mut got = $typ::from_attrs_inner(&[attr]); |
| let expect: Result<Repr<_, _>, _> = $repr; |
| if false { |
| // Force Rust to infer `got` as having the same type as |
| // `expect`. |
| got = expect; |
| } |
| assert_eq!(got, expect, stringify!($(#[$attr])*)); |
| }; |
| } |
| |
| use {AlignRepr::*, CompoundRepr::*, PrimitiveRepr::*}; |
| let nz = |n: u32| NonZeroU32::new(n).unwrap(); |
| |
| test!(#[repr(transparent)] => StructUnionRepr::Transparent(s())); |
| test!(#[repr()] => StructUnionRepr::Compound(Rust.into(), None)); |
| test!(#[repr(packed)] => StructUnionRepr::Compound(Rust.into(), Some(Packed(nz(1)).into()))); |
| test!(#[repr(packed(2))] => StructUnionRepr::Compound(Rust.into(), Some(Packed(nz(2)).into()))); |
| test!(#[repr(align(1))] => StructUnionRepr::Compound(Rust.into(), Some(Align(nz(1)).into()))); |
| test!(#[repr(align(2))] => StructUnionRepr::Compound(Rust.into(), Some(Align(nz(2)).into()))); |
| test!(#[repr(C)] => StructUnionRepr::Compound(C.into(), None)); |
| test!(#[repr(C, packed)] => StructUnionRepr::Compound(C.into(), Some(Packed(nz(1)).into()))); |
| test!(#[repr(C, packed(2))] => StructUnionRepr::Compound(C.into(), Some(Packed(nz(2)).into()))); |
| test!(#[repr(C, align(1))] => StructUnionRepr::Compound(C.into(), Some(Align(nz(1)).into()))); |
| test!(#[repr(C, align(2))] => StructUnionRepr::Compound(C.into(), Some(Align(nz(2)).into()))); |
| |
| test!(#[repr(transparent)] => EnumRepr::Transparent(s())); |
| test!(#[repr()] => EnumRepr::Compound(Rust.into(), None)); |
| test!(#[repr(align(1))] => EnumRepr::Compound(Rust.into(), Some(Align(nz(1)).into()))); |
| test!(#[repr(align(2))] => EnumRepr::Compound(Rust.into(), Some(Align(nz(2)).into()))); |
| |
| macro_rules! for_each_compound_repr { |
| ($($r:tt => $var:expr),*) => { |
| $( |
| test!(#[repr($r)] => EnumRepr::Compound($var.into(), None)); |
| test!(#[repr($r, align(1))] => EnumRepr::Compound($var.into(), Some(Align(nz(1)).into()))); |
| test!(#[repr($r, align(2))] => EnumRepr::Compound($var.into(), Some(Align(nz(2)).into()))); |
| )* |
| } |
| } |
| |
| for_each_compound_repr!( |
| C => C, |
| u8 => Primitive(U8), |
| u16 => Primitive(U16), |
| u32 => Primitive(U32), |
| u64 => Primitive(U64), |
| usize => Primitive(Usize), |
| i8 => Primitive(I8), |
| i16 => Primitive(I16), |
| i32 => Primitive(I32), |
| i64 => Primitive(I64), |
| isize => Primitive(Isize) |
| ); |
| |
| use {FromAttrsError::*, FromRawReprsError::*}; |
| |
| // Run failure tests which are valid for both `StructUnionRepr` and |
| // `EnumRepr`. |
| macro_rules! for_each_repr_type { |
| ($($repr:ident),*) => { |
| $( |
| // Invalid packed or align attributes |
| test!(@error #[repr(packed(0))] => $repr => Unrecognized.into()); |
| test!(@error #[repr(packed(3))] => $repr => Unrecognized.into()); |
| test!(@error #[repr(align(0))] => $repr => Unrecognized.into()); |
| test!(@error #[repr(align(3))] => $repr => Unrecognized.into()); |
| |
| // Conflicts |
| test!(@error #[repr(transparent, transparent)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(transparent, C)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(transparent, Rust)] => $repr => FromRawReprs(Conflict).into()); |
| |
| test!(@error #[repr(C, transparent)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(C, C)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(C, Rust)] => $repr => FromRawReprs(Conflict).into()); |
| |
| test!(@error #[repr(Rust, transparent)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(Rust, C)] => $repr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(Rust, Rust)] => $repr => FromRawReprs(Conflict).into()); |
| )* |
| } |
| } |
| |
| for_each_repr_type!(StructUnionRepr, EnumRepr); |
| |
| // Enum-specific conflicts. |
| // |
| // We don't bother to test every combination since that would be a huge |
| // number (enums can have primitive reprs u8, u16, u32, u64, usize, i8, |
| // i16, i32, i64, and isize). Instead, since the conflict logic doesn't |
| // care what specific value of `PrimitiveRepr` is present, we assume |
| // that testing against u8 alone is fine. |
| test!(@error #[repr(transparent, u8)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(u8, transparent)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(C, u8)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(u8, C)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(Rust, u8)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(u8, Rust)] => EnumRepr => FromRawReprs(Conflict).into()); |
| test!(@error #[repr(u8, u8)] => EnumRepr => FromRawReprs(Conflict).into()); |
| |
| // Illegal struct/union reprs |
| test!(@error #[repr(u8)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(u16)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(u32)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(u64)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(usize)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(i8)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(i16)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(i32)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(i64)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(isize)] => StructUnionRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| |
| // Illegal enum reprs |
| test!(@error #[repr(packed)] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(packed(1))] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| test!(@error #[repr(packed(2))] => EnumRepr => FromRawReprs(Single(UnsupportedReprError)).into()); |
| } |
| } |
