// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT//// 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. //! Derive macros for [zerocopy]'s traits.//!//! [zerocopy]: https://docs.rs/zerocopy // Sometimes we want to use lints which were added after our MSRV.// `unknown_lints` is `warn` by default and we deny warnings in CI, so without// this attribute, any unknown lint would cause a CI failure when testing with// our MSRV.#![allow(unknown_lints)]#![deny(renamed_and_removed_lints)]#![deny( clippy::all, clippy::missing_safety_doc, clippy::multiple_unsafe_ops_per_block, clippy::undocumented_unsafe_blocks)]// We defer to own discretion on type complexity.#![allow(clippy::type_complexity)]// Inlining format args isn't supported on our MSRV.#![allow(clippy::uninlined_format_args)]#![deny( rustdoc::bare_urls, rustdoc::broken_intra_doc_links, rustdoc::invalid_codeblock_attributes, rustdoc::invalid_html_tags, rustdoc::invalid_rust_codeblocks, rustdoc::missing_crate_level_docs, rustdoc::private_intra_doc_links)]#![recursion_limit = "128"] macro_rules! ident { (($fmt:literal $(, $arg:expr)*), $span:expr) => { syn::Ident::new(&format!($fmt $(, crate::util::to_ident_str($arg))*), $span) };} mod derive;#[cfg(test)]mod output_tests;mod repr;mod util; use syn::{DeriveInput, Error}; use crate::util::*; // FIXME(https://github.com/rust-lang/rust/issues/54140): Some errors could be// made better if we could add multiple lines of error output like this://// error: unsupported representation// --> enum.rs:28:8// |// 28 | #[repr(transparent)]// |// help: required by the derive of FromBytes//// Instead, we have more verbose error messages like "unsupported representation// for deriving FromZeros, FromBytes, IntoBytes, or Unaligned on an enum"//// This will probably require Span::error// (https://doc.rust-lang.org/nightly/proc_macro/struct.Span.html#method.error),// which is currently unstable. Revisit this once it's stable. /// Defines a derive function named `$outer` which parses its input/// `TokenStream` as a `DeriveInput` and then invokes the `$inner` function.////// Note that the separate `$outer` parameter is required - proc macro functions/// are currently required to live at the crate root, and so the caller must/// specify the name in order to avoid name collisions.macro_rules! derive { ($trait:ident => $outer:ident => $inner:path) => { #[proc_macro_derive($trait, attributes(zerocopy))] pub fn $outer(ts: proc_macro::TokenStream) -> proc_macro::TokenStream { let ast = syn::parse_macro_input!(ts as DeriveInput); let ctx = match Ctx::try_from_derive_input(ast) { Ok(ctx) => ctx, Err(e) => return e.into_compile_error().into(), }; let ts = $inner(&ctx, Trait::$trait).into_ts(); // We wrap in `const_block` as a backstop in case any derive fails // to wrap its output in `const_block` (and thus fails to annotate) // with the full set of `#[allow(...)]` attributes). let ts = const_block([Some(ts)]); #[cfg(test)] crate::util::testutil::check_hygiene(ts.clone()); ts.into() } };} trait IntoTokenStream { fn into_ts(self) -> proc_macro2::TokenStream;} impl IntoTokenStream for proc_macro2::TokenStream { fn into_ts(self) -> proc_macro2::TokenStream { self }} impl IntoTokenStream for Result<proc_macro2::TokenStream, Error> { fn into_ts(self) -> proc_macro2::TokenStream { match self { Ok(ts) => ts, Err(err) => err.to_compile_error(), } }} derive!(KnownLayout => derive_known_layout => crate::derive::known_layout::derive);derive!(Immutable => derive_immutable => crate::derive::derive_immutable);derive!(TryFromBytes => derive_try_from_bytes => crate::derive::try_from_bytes::derive_try_from_bytes);derive!(FromZeros => derive_from_zeros => crate::derive::from_bytes::derive_from_zeros);derive!(FromBytes => derive_from_bytes => crate::derive::from_bytes::derive_from_bytes);derive!(IntoBytes => derive_into_bytes => crate::derive::into_bytes::derive_into_bytes);derive!(Unaligned => derive_unaligned => crate::derive::unaligned::derive_unaligned);derive!(ByteHash => derive_hash => crate::derive::derive_hash);derive!(ByteEq => derive_eq => crate::derive::derive_eq);derive!(SplitAt => derive_split_at => crate::derive::derive_split_at); #[cfg_attr(not(zerocopy_unstable_linux), doc(hidden))]#[proc_macro_derive(most_traits, attributes(zerocopy))]pub fn most_traits(ts: proc_macro::TokenStream) -> proc_macro::TokenStream { let ast = syn::parse_macro_input!(ts as DeriveInput); let ctx = match Ctx::try_from_derive_input(ast) { Ok(ctx) => ctx, Err(e) => return e.into_compile_error().into(), } .skip_on_error(); // top-level traits for which to attempt a derive let derives: [(fn(&Ctx, Trait) -> _, _); 6] = [ (crate::derive::known_layout::derive, Trait::KnownLayout), (crate::derive::derive_immutable, Trait::Immutable), (crate::derive::from_bytes::derive_from_bytes, Trait::FromBytes), (crate::derive::into_bytes::derive_into_bytes, Trait::IntoBytes), (crate::derive::derive_split_at, Trait::SplitAt), (crate::derive::unaligned::derive_unaligned, Trait::Unaligned), ]; let mut tokens = proc_macro2::TokenStream::new(); for (derive, t) in derives { tokens.extend(derive(&ctx, t)) } // We wrap in `const_block` as a backstop in case any derive fails // to wrap its output in `const_block` (and thus fails to annotate) // with the full set of `#[allow(...)]` attributes). let ts = const_block([Some(tokens)]); #[cfg(test)] crate::util::testutil::check_hygiene(ts.clone()); ts.into()} /// Deprecated: prefer [`FromZeros`] instead.#[deprecated(since = "0.8.0", note = "`FromZeroes` was renamed to `FromZeros`")]#[doc(hidden)]#[proc_macro_derive(FromZeroes)]pub fn derive_from_zeroes(ts: proc_macro::TokenStream) -> proc_macro::TokenStream { derive_from_zeros(ts)} /// Deprecated: prefer [`IntoBytes`] instead.#[deprecated(since = "0.8.0", note = "`AsBytes` was renamed to `IntoBytes`")]#[doc(hidden)]#[proc_macro_derive(AsBytes)]pub fn derive_as_bytes(ts: proc_macro::TokenStream) -> proc_macro::TokenStream { derive_into_bytes(ts)}
// SPDX-License-Identifier: (BSD-2-Clause OR Apache-2.0) OR MIT
//
// 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.
//! Derive macros for [zerocopy]'s traits.
//!
//! [zerocopy]: https://docs.rs/zerocopy
// Sometimes we want to use lints which were added after our MSRV.
// `unknown_lints` is `warn` by default and we deny warnings in CI, so without
// this attribute, any unknown lint would cause a CI failure when testing with
// our MSRV.
#![allow(unknown_lints)]
#![deny(renamed_and_removed_lints)]
#![deny(
clippy::all,
clippy::missing_safety_doc,
clippy::multiple_unsafe_ops_per_block,
clippy::undocumented_unsafe_blocks
)]
// We defer to own discretion on type complexity.
#![allow(clippy::type_complexity)]
// Inlining format args isn't supported on our MSRV.
#![allow(clippy::uninlined_format_args)]
#![deny(
rustdoc::bare_urls,
rustdoc::broken_intra_doc_links,
rustdoc::invalid_codeblock_attributes,
rustdoc::invalid_html_tags,
rustdoc::invalid_rust_codeblocks,
rustdoc::missing_crate_level_docs,
rustdoc::private_intra_doc_links
)]
#![recursion_limit = "128"]
macro_rules! ident {
(($fmt:literal $(, $arg:expr)*), $span:expr) => {
syn::Ident::new(&format!($fmt $(, crate::util::to_ident_str($arg))*), $span)
};
}
mod derive;
#[cfg(test)]
mod output_tests;
mod repr;
mod util;
use syn::{DeriveInput, Error};
use crate::util::*;
// FIXME(https://github.com/rust-lang/rust/issues/54140): Some errors could be
// made better if we could add multiple lines of error output like this:
//
// error: unsupported representation
// --> enum.rs:28:8
// |
// 28 | #[repr(transparent)]
// |
// help: required by the derive of FromBytes
//
// Instead, we have more verbose error messages like "unsupported representation
// for deriving FromZeros, FromBytes, IntoBytes, or Unaligned on an enum"
//
// This will probably require Span::error
// (https://doc.rust-lang.org/nightly/proc_macro/struct.Span.html#method.error),
// which is currently unstable. Revisit this once it's stable.
/// Defines a derive function named `$outer` which parses its input
/// `TokenStream` as a `DeriveInput` and then invokes the `$inner` function.
///
/// Note that the separate `$outer` parameter is required - proc macro functions
/// are currently required to live at the crate root, and so the caller must
/// specify the name in order to avoid name collisions.
macro_rules! derive {
($trait:ident => $outer:ident => $inner:path) => {
#[proc_macro_derive($trait, attributes(zerocopy))]
pub fn $outer(ts: proc_macro::TokenStream) -> proc_macro::TokenStream {
let ast = syn::parse_macro_input!(ts as DeriveInput);
let ctx = match Ctx::try_from_derive_input(ast) {
Ok(ctx) => ctx,
Err(e) => return e.into_compile_error().into(),
};
let ts = $inner(&ctx, Trait::$trait).into_ts();
// We wrap in `const_block` as a backstop in case any derive fails
// to wrap its output in `const_block` (and thus fails to annotate)
// with the full set of `#[allow(...)]` attributes).
let ts = const_block([Some(ts)]);
#[cfg(test)]
crate::util::testutil::check_hygiene(ts.clone());
ts.into()
}
};
}
trait IntoTokenStream {
fn into_ts(self) -> proc_macro2::TokenStream;
}
impl IntoTokenStream for proc_macro2::TokenStream {
fn into_ts(self) -> proc_macro2::TokenStream {
self
}
}
impl IntoTokenStream for Result<proc_macro2::TokenStream, Error> {
fn into_ts(self) -> proc_macro2::TokenStream {
match self {
Ok(ts) => ts,
Err(err) => err.to_compile_error(),
}
}
}
derive!(KnownLayout => derive_known_layout => crate::derive::known_layout::derive);
derive!(Immutable => derive_immutable => crate::derive::derive_immutable);
derive!(TryFromBytes => derive_try_from_bytes => crate::derive::try_from_bytes::derive_try_from_bytes);
derive!(FromZeros => derive_from_zeros => crate::derive::from_bytes::derive_from_zeros);
derive!(FromBytes => derive_from_bytes => crate::derive::from_bytes::derive_from_bytes);
derive!(IntoBytes => derive_into_bytes => crate::derive::into_bytes::derive_into_bytes);
derive!(Unaligned => derive_unaligned => crate::derive::unaligned::derive_unaligned);
derive!(ByteHash => derive_hash => crate::derive::derive_hash);
derive!(ByteEq => derive_eq => crate::derive::derive_eq);
derive!(SplitAt => derive_split_at => crate::derive::derive_split_at);
#[cfg_attr(not(zerocopy_unstable_linux), doc(hidden))]
#[proc_macro_derive(most_traits, attributes(zerocopy))]
pub fn most_traits(ts: proc_macro::TokenStream) -> proc_macro::TokenStream {
let ast = syn::parse_macro_input!(ts as DeriveInput);
let ctx = match Ctx::try_from_derive_input(ast) {
Ok(ctx) => ctx,
Err(e) => return e.into_compile_error().into(),
}
.skip_on_error();
// top-level traits for which to attempt a derive
let derives: [(fn(&Ctx, Trait) -> _, _); 6] = [
(crate::derive::known_layout::derive, Trait::KnownLayout),
(crate::derive::derive_immutable, Trait::Immutable),
(crate::derive::from_bytes::derive_from_bytes, Trait::FromBytes),
(crate::derive::into_bytes::derive_into_bytes, Trait::IntoBytes),
(crate::derive::derive_split_at, Trait::SplitAt),
(crate::derive::unaligned::derive_unaligned, Trait::Unaligned),
];
let mut tokens = proc_macro2::TokenStream::new();
for (derive, t) in derives {
tokens.extend(derive(&ctx, t))
}
// We wrap in `const_block` as a backstop in case any derive fails
// to wrap its output in `const_block` (and thus fails to annotate)
// with the full set of `#[allow(...)]` attributes).
let ts = const_block([Some(tokens)]);
#[cfg(test)]
crate::util::testutil::check_hygiene(ts.clone());
ts.into()
}
/// Deprecated: prefer [`FromZeros`] instead.
#[deprecated(since = "0.8.0", note = "`FromZeroes` was renamed to `FromZeros`")]
#[doc(hidden)]
#[proc_macro_derive(FromZeroes)]
pub fn derive_from_zeroes(ts: proc_macro::TokenStream) -> proc_macro::TokenStream {
derive_from_zeros(ts)
}
/// Deprecated: prefer [`IntoBytes`] instead.
#[deprecated(since = "0.8.0", note = "`AsBytes` was renamed to `IntoBytes`")]
#[doc(hidden)]
#[proc_macro_derive(AsBytes)]
pub fn derive_as_bytes(ts: proc_macro::TokenStream) -> proc_macro::TokenStream {
derive_into_bytes(ts)
}