From 9cc63f8bcd560c760d0b12e15bba8f81c86237cf Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 14 Aug 2026 15:43:51 -0700 Subject: Merge branches 'expcb.2026.07.24a', 'misc.2026.07.30a', 'rcu-tasks.2026.07.30a', 'srcu.2026.08.11a' and 'torture.2026.08.14a' into HEAD Changes: Make expedited grace periods expedite normal RCU callbacks Miscellaneous fixes: * Improve diagnostic output with character task states. * Mark accesses to inform KCSAN of concurrency design. * Move from kmalloc() to kmalloc_obj(). * Documentation updates. * Improve handling of RCU deferred quiescent states. * Clean up unused function arguments and structure fields. * Reduce show_rcu_gp_kthreads() stack space. Tasks RCU updates: * Clean up after SRCU re-implementation of Tasks Trace RCU. * Mark accesses to inform KCSAN of concurrency design. * Add ->lazy_timer status to diagnostic output. * Remove an unnecessary memory barrier. * Fix a data race, courtesy of KCSAN. * Documentation updates. * Convert cond_resched_tasks_rcu_qs() from macro to static inline function. SRCU updates: * Add Rust helpers for SRCU. * Avoid losing queued work at cleanup_srcu_struct() time. Torture-test updates: * Preparation work for immediate RCU priority deboosting. * Test RCU readers from real interrupt handlers (as opposed to softirq). * Simplify code through use of cpumask_next_wrap(). * Improve diagnostic output with character task states. * Add rcutorture.nwriters parameter to allow lightweight stall testing, and rcutorture.stall_only to make doing so easier. * Test an RCU Tasks Trace grace period implying an RCU grace period. * Make RCU Tasks Trace torturing track reader batches. * Fix a data race, courtesy of KCSAN. * Plug a shuffle_tmp_mask memory leak on kthread spawn failure. --- rust/syn/lifetime.rs | 158 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 158 insertions(+) create mode 100644 rust/syn/lifetime.rs (limited to 'rust/syn/lifetime.rs') diff --git a/rust/syn/lifetime.rs b/rust/syn/lifetime.rs new file mode 100644 index 000000000..24bec7fe9 --- /dev/null +++ b/rust/syn/lifetime.rs @@ -0,0 +1,158 @@ +// SPDX-License-Identifier: Apache-2.0 OR MIT + +#[cfg(feature = "parsing")] +use crate::lookahead; +use proc_macro2::{Ident, Span}; +use std::cmp::Ordering; +use std::fmt::{self, Display}; +use std::hash::{Hash, Hasher}; + +/// A Rust lifetime: `'a`. +/// +/// Lifetime names must conform to the following rules: +/// +/// - Must start with an apostrophe. +/// - Must not consist of just an apostrophe: `'`. +/// - Character after the apostrophe must be `_` or a Unicode code point with +/// the XID_Start property. +/// - All following characters must be Unicode code points with the XID_Continue +/// property. +pub struct Lifetime { + pub apostrophe: Span, + pub ident: Ident, +} + +impl Lifetime { + /// # Panics + /// + /// Panics if the lifetime does not conform to the bulleted rules above. + /// + /// # Invocation + /// + /// ``` + /// # use proc_macro2::Span; + /// # use syn::Lifetime; + /// # + /// # fn f() -> Lifetime { + /// Lifetime::new("'a", Span::call_site()) + /// # } + /// ``` + pub fn new(symbol: &str, span: Span) -> Self { + if !symbol.starts_with('\'') { + panic!( + "lifetime name must start with apostrophe as in \"'a\", got {:?}", + symbol + ); + } + + if symbol == "'" { + panic!("lifetime name must not be empty"); + } + + if !crate::ident::xid_ok(&symbol[1..]) { + panic!("{:?} is not a valid lifetime name", symbol); + } + + Lifetime { + apostrophe: span, + ident: Ident::new(&symbol[1..], span), + } + } + + pub fn span(&self) -> Span { + self.apostrophe + .join(self.ident.span()) + .unwrap_or(self.apostrophe) + } + + pub fn set_span(&mut self, span: Span) { + self.apostrophe = span; + self.ident.set_span(span); + } +} + +impl Display for Lifetime { + fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result { + "'".fmt(formatter)?; + self.ident.fmt(formatter) + } +} + +impl Clone for Lifetime { + fn clone(&self) -> Self { + Lifetime { + apostrophe: self.apostrophe, + ident: self.ident.clone(), + } + } +} + +impl PartialEq for Lifetime { + fn eq(&self, other: &Lifetime) -> bool { + self.ident.eq(&other.ident) + } +} + +impl Eq for Lifetime {} + +impl PartialOrd for Lifetime { + fn partial_cmp(&self, other: &Lifetime) -> Option { + Some(self.cmp(other)) + } +} + +impl Ord for Lifetime { + fn cmp(&self, other: &Lifetime) -> Ordering { + self.ident.cmp(&other.ident) + } +} + +impl Hash for Lifetime { + fn hash(&self, h: &mut H) { + self.ident.hash(h); + } +} + +#[cfg(feature = "parsing")] +pub_if_not_doc! { + #[doc(hidden)] + #[allow(non_snake_case)] + pub fn Lifetime(marker: lookahead::TokenMarker) -> Lifetime { + match marker {} + } +} + +#[cfg(feature = "parsing")] +pub(crate) mod parsing { + use crate::error::Result; + use crate::lifetime::Lifetime; + use crate::parse::{Parse, ParseStream}; + + #[cfg_attr(docsrs, doc(cfg(feature = "parsing")))] + impl Parse for Lifetime { + fn parse(input: ParseStream) -> Result { + input.step(|cursor| { + cursor + .lifetime() + .ok_or_else(|| cursor.error("expected lifetime")) + }) + } + } +} + +#[cfg(feature = "printing")] +mod printing { + use crate::lifetime::Lifetime; + use proc_macro2::{Punct, Spacing, TokenStream}; + use quote::{ToTokens, TokenStreamExt}; + + #[cfg_attr(docsrs, doc(cfg(feature = "printing")))] + impl ToTokens for Lifetime { + fn to_tokens(&self, tokens: &mut TokenStream) { + let mut apostrophe = Punct::new('\'', Spacing::Joint); + apostrophe.set_span(self.apostrophe); + tokens.append(apostrophe); + self.ident.to_tokens(tokens); + } + } +} -- cgit v1.3.1