diff options
Diffstat (limited to 'library/std/src/thread/local.rs')
| -rw-r--r-- | library/std/src/thread/local.rs | 233 |
1 files changed, 213 insertions, 20 deletions
diff --git a/library/std/src/thread/local.rs b/library/std/src/thread/local.rs index 0a6f2e5d508..4259a4d1f3b 100644 --- a/library/std/src/thread/local.rs +++ b/library/std/src/thread/local.rs @@ -132,6 +132,216 @@ impl<T: 'static> fmt::Debug for LocalKey<T> { } } +#[doc(hidden)] +#[allow_internal_unstable(thread_local_internals)] +#[unstable(feature = "thread_local_internals", issue = "none")] +#[rustc_macro_transparency = "semitransparent"] +pub macro thread_local_process_attrs { + + // Parse `cfg_attr` to figure out whether it's a `rustc_align_static`. + // Each `cfg_attr` can have zero or more attributes on the RHS, and can be nested. + + // finished parsing the `cfg_attr`, it had no `rustc_align_static` + ( + [] [$(#[$($prev_other_attrs:tt)*])*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [] }; + [$($prev_align_attrs_ret:tt)*] [$($prev_other_attrs_ret:tt)*]; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs_ret)*] [$($prev_other_attrs_ret)* #[cfg_attr($($predicate)*, $($($prev_other_attrs)*),*)]]; + $($rest)* + ); + ), + + // finished parsing the `cfg_attr`, it had nothing but `rustc_align_static` + ( + [$(#[$($prev_align_attrs:tt)*])+] []; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [] }; + [$($prev_align_attrs_ret:tt)*] [$($prev_other_attrs_ret:tt)*]; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs_ret)* #[cfg_attr($($predicate)*, $($($prev_align_attrs)*),+)]] [$($prev_other_attrs_ret)*]; + $($rest)* + ); + ), + + // finished parsing the `cfg_attr`, it had a mix of `rustc_align_static` and other attrs + ( + [$(#[$($prev_align_attrs:tt)*])+] [$(#[$($prev_other_attrs:tt)*])+]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [] }; + [$($prev_align_attrs_ret:tt)*] [$($prev_other_attrs_ret:tt)*]; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs_ret)* #[cfg_attr($($predicate)*, $($($prev_align_attrs)*),+)]] [$($prev_other_attrs_ret)* #[cfg_attr($($predicate)*, $($($prev_other_attrs)*),+)]]; + $($rest)* + ); + ), + + // it's a `rustc_align_static` + ( + [$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [rustc_align_static($($align_static_args:tt)*) $(, $($attr_rhs:tt)*)?] }; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)* #[rustc_align_static($($align_static_args)*)]] [$($prev_other_attrs)*]; + @processing_cfg_attr { pred: ($($predicate)*), rhs: [$($($attr_rhs)*)?] }; + $($rest)* + ); + ), + + // it's a nested `cfg_attr(true, ...)`; recurse into RHS + ( + [$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [cfg_attr(true, $($cfg_rhs:tt)*) $(, $($attr_rhs:tt)*)?] }; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: (true), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + @processing_cfg_attr { pred: ($($predicate)*), rhs: [$($($attr_rhs)*)?] }; + $($rest)* + ); + ), + + // it's a nested `cfg_attr(false, ...)`; recurse into RHS + ( + [$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [cfg_attr(false, $($cfg_rhs:tt)*) $(, $($attr_rhs:tt)*)?] }; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: (false), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + @processing_cfg_attr { pred: ($($predicate)*), rhs: [$($($attr_rhs)*)?] }; + $($rest)* + ); + ), + + + // it's a nested `cfg_attr(..., ...)`; recurse into RHS + ( + [$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [cfg_attr($cfg_lhs:meta, $($cfg_rhs:tt)*) $(, $($attr_rhs:tt)*)?] }; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: ($cfg_lhs), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + @processing_cfg_attr { pred: ($($predicate)*), rhs: [$($($attr_rhs)*)?] }; + $($rest)* + ); + ), + + // it's some other attribute + ( + [$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + @processing_cfg_attr { pred: ($($predicate:tt)*), rhs: [$meta:meta $(, $($attr_rhs:tt)*)?] }; + $($rest:tt)* + ) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)*] [$($prev_other_attrs)* #[$meta]]; + @processing_cfg_attr { pred: ($($predicate)*), rhs: [$($($attr_rhs)*)?] }; + $($rest)* + ); + ), + + + // Separate attributes into `rustc_align_static` and everything else: + + // `rustc_align_static` attribute + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; #[rustc_align_static $($attr_rest:tt)*] $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)* #[rustc_align_static $($attr_rest)*]] [$($prev_other_attrs)*]; + $($rest)* + ); + ), + + // `cfg_attr(true, ...)` attribute; parse it + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; #[cfg_attr(true, $($cfg_rhs:tt)*)] $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: (true), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + $($rest)* + ); + ), + + // `cfg_attr(false, ...)` attribute; parse it + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; #[cfg_attr(false, $($cfg_rhs:tt)*)] $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: (false), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + $($rest)* + ); + ), + + // `cfg_attr(..., ...)` attribute; parse it + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; #[cfg_attr($cfg_pred:meta, $($cfg_rhs:tt)*)] $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [] []; + @processing_cfg_attr { pred: ($cfg_pred), rhs: [$($cfg_rhs)*] }; + [$($prev_align_attrs)*] [$($prev_other_attrs)*]; + $($rest)* + ); + ), + + // doc comment not followed by any other attributes; process it all at once to avoid blowing recursion limit + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; $(#[doc $($doc_rhs:tt)*])+ $vis:vis static $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)*] [$($prev_other_attrs)* $(#[doc $($doc_rhs)*])+]; + $vis static $($rest)* + ); + ), + + // 8 lines of doc comment; process them all at once to avoid blowing recursion limit + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; + #[doc $($doc_rhs_1:tt)*] #[doc $($doc_rhs_2:tt)*] #[doc $($doc_rhs_3:tt)*] #[doc $($doc_rhs_4:tt)*] + #[doc $($doc_rhs_5:tt)*] #[doc $($doc_rhs_6:tt)*] #[doc $($doc_rhs_7:tt)*] #[doc $($doc_rhs_8:tt)*] + $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)*] [$($prev_other_attrs)* + #[doc $($doc_rhs_1)*] #[doc $($doc_rhs_2)*] #[doc $($doc_rhs_3)*] #[doc $($doc_rhs_4)*] + #[doc $($doc_rhs_5)*] #[doc $($doc_rhs_6)*] #[doc $($doc_rhs_7)*] #[doc $($doc_rhs_8)*]]; + $($rest)* + ); + ), + + // other attribute + ([$($prev_align_attrs:tt)*] [$($prev_other_attrs:tt)*]; #[$($attr:tt)*] $($rest:tt)*) => ( + $crate::thread::local_impl::thread_local_process_attrs!( + [$($prev_align_attrs)*] [$($prev_other_attrs)* #[$($attr)*]]; + $($rest)* + ); + ), + + + // Delegate to `thread_local_inner` once attributes are fully categorized: + + // process `const` declaration and recurse + ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = const $init:block $(; $($($rest:tt)+)?)?) => ( + $($other_attrs)* $vis const $name: $crate::thread::LocalKey<$t> = + $crate::thread::local_impl::thread_local_inner!(@key $t, $($align_attrs)*, const $init); + + $($($crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)+);)?)? + ), + + // process non-`const` declaration and recurse + ([$($align_attrs:tt)*] [$($other_attrs:tt)*]; $vis:vis static $name:ident: $t:ty = $init:expr $(; $($($rest:tt)+)?)?) => ( + $($other_attrs)* $vis const $name: $crate::thread::LocalKey<$t> = + $crate::thread::local_impl::thread_local_inner!(@key $t, $($align_attrs)*, $init); + + $($($crate::thread::local_impl::thread_local_process_attrs!([] []; $($rest)+);)?)? + ), +} + /// Declare a new thread local storage key of type [`std::thread::LocalKey`]. /// /// # Syntax @@ -182,28 +392,11 @@ impl<T: 'static> fmt::Debug for LocalKey<T> { #[cfg_attr(not(test), rustc_diagnostic_item = "thread_local_macro")] #[allow_internal_unstable(thread_local_internals)] macro_rules! thread_local { - // empty (base case for the recursion) () => {}; - ($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = const $init:block; $($rest:tt)*) => ( - $crate::thread::local_impl::thread_local_inner!($(#[$attr])* $vis $name, $t, const $init); - $crate::thread_local!($($rest)*); - ); - - ($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = const $init:block) => ( - $crate::thread::local_impl::thread_local_inner!($(#[$attr])* $vis $name, $t, const $init); - ); - - // process multiple declarations - ($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = $init:expr; $($rest:tt)*) => ( - $crate::thread::local_impl::thread_local_inner!($(#[$attr])* $vis $name, $t, $init); - $crate::thread_local!($($rest)*); - ); - - // handle a single declaration - ($(#[$attr:meta])* $vis:vis static $name:ident: $t:ty = $init:expr) => ( - $crate::thread::local_impl::thread_local_inner!($(#[$attr])* $vis $name, $t, $init); - ); + ($($tt:tt)+) => { + $crate::thread::local_impl::thread_local_process_attrs!([] []; $($tt)+); + }; } /// An error returned by [`LocalKey::try_with`](struct.LocalKey.html#method.try_with). |