aboutsummaryrefslogtreecommitdiff
path: root/vendor/proc-macro2/src/detection.rs
diff options
context:
space:
mode:
authorValentin Popov <valentin@popov.link>2024-07-19 15:37:58 +0300
committerValentin Popov <valentin@popov.link>2024-07-19 15:37:58 +0300
commita990de90fe41456a23e58bd087d2f107d321f3a1 (patch)
tree15afc392522a9e85dc3332235e311b7d39352ea9 /vendor/proc-macro2/src/detection.rs
parent3d48cd3f81164bbfc1a755dc1d4a9a02f98c8ddd (diff)
downloadfparkan-a990de90fe41456a23e58bd087d2f107d321f3a1.tar.xz
fparkan-a990de90fe41456a23e58bd087d2f107d321f3a1.zip
Deleted vendor folder
Diffstat (limited to 'vendor/proc-macro2/src/detection.rs')
-rw-r--r--vendor/proc-macro2/src/detection.rs75
1 files changed, 0 insertions, 75 deletions
diff --git a/vendor/proc-macro2/src/detection.rs b/vendor/proc-macro2/src/detection.rs
deleted file mode 100644
index beba7b2..0000000
--- a/vendor/proc-macro2/src/detection.rs
+++ /dev/null
@@ -1,75 +0,0 @@
-use core::sync::atomic::{AtomicUsize, Ordering};
-use std::sync::Once;
-
-static WORKS: AtomicUsize = AtomicUsize::new(0);
-static INIT: Once = Once::new();
-
-pub(crate) fn inside_proc_macro() -> bool {
- match WORKS.load(Ordering::Relaxed) {
- 1 => return false,
- 2 => return true,
- _ => {}
- }
-
- INIT.call_once(initialize);
- inside_proc_macro()
-}
-
-pub(crate) fn force_fallback() {
- WORKS.store(1, Ordering::Relaxed);
-}
-
-pub(crate) fn unforce_fallback() {
- initialize();
-}
-
-#[cfg(not(no_is_available))]
-fn initialize() {
- let available = proc_macro::is_available();
- WORKS.store(available as usize + 1, Ordering::Relaxed);
-}
-
-// Swap in a null panic hook to avoid printing "thread panicked" to stderr,
-// then use catch_unwind to determine whether the compiler's proc_macro is
-// working. When proc-macro2 is used from outside of a procedural macro all
-// of the proc_macro crate's APIs currently panic.
-//
-// The Once is to prevent the possibility of this ordering:
-//
-// thread 1 calls take_hook, gets the user's original hook
-// thread 1 calls set_hook with the null hook
-// thread 2 calls take_hook, thinks null hook is the original hook
-// thread 2 calls set_hook with the null hook
-// thread 1 calls set_hook with the actual original hook
-// thread 2 calls set_hook with what it thinks is the original hook
-//
-// in which the user's hook has been lost.
-//
-// There is still a race condition where a panic in a different thread can
-// happen during the interval that the user's original panic hook is
-// unregistered such that their hook is incorrectly not called. This is
-// sufficiently unlikely and less bad than printing panic messages to stderr
-// on correct use of this crate. Maybe there is a libstd feature request
-// here. For now, if a user needs to guarantee that this failure mode does
-// not occur, they need to call e.g. `proc_macro2::Span::call_site()` from
-// the main thread before launching any other threads.
-#[cfg(no_is_available)]
-fn initialize() {
- use std::panic::{self, PanicInfo};
-
- type PanicHook = dyn Fn(&PanicInfo) + Sync + Send + 'static;
-
- let null_hook: Box<PanicHook> = Box::new(|_panic_info| { /* ignore */ });
- let sanity_check = &*null_hook as *const PanicHook;
- let original_hook = panic::take_hook();
- panic::set_hook(null_hook);
-
- let works = panic::catch_unwind(proc_macro::Span::call_site).is_ok();
- WORKS.store(works as usize + 1, Ordering::Relaxed);
-
- let hopefully_null_hook = panic::take_hook();
- panic::set_hook(original_hook);
- if sanity_check != &*hopefully_null_hook {
- panic!("observed race condition in proc_macro2::inside_proc_macro");
- }
-}