bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/ra-salsa/tests/parallel/signal.rs')
-rw-r--r--crates/ra-salsa/tests/parallel/signal.rs40
1 files changed, 40 insertions, 0 deletions
diff --git a/crates/ra-salsa/tests/parallel/signal.rs b/crates/ra-salsa/tests/parallel/signal.rs
new file mode 100644
index 0000000000..0af7b66e48
--- /dev/null
+++ b/crates/ra-salsa/tests/parallel/signal.rs
@@ -0,0 +1,40 @@
+use parking_lot::{Condvar, Mutex};
+
+#[derive(Default)]
+pub(crate) struct Signal {
+ value: Mutex<usize>,
+ cond_var: Condvar,
+}
+
+impl Signal {
+ pub(crate) fn signal(&self, stage: usize) {
+ tracing::debug!("signal({})", stage);
+
+ // This check avoids acquiring the lock for things that will
+ // clearly be a no-op. Not *necessary* but helps to ensure we
+ // are more likely to encounter weird race conditions;
+ // otherwise calls to `sum` will tend to be unnecessarily
+ // synchronous.
+ if stage > 0 {
+ let mut v = self.value.lock();
+ if stage > *v {
+ *v = stage;
+ self.cond_var.notify_all();
+ }
+ }
+ }
+
+ /// Waits until the given condition is true; the fn is invoked
+ /// with the current stage.
+ pub(crate) fn wait_for(&self, stage: usize) {
+ tracing::debug!("wait_for({})", stage);
+
+ // As above, avoid lock if clearly a no-op.
+ if stage > 0 {
+ let mut v = self.value.lock();
+ while *v < stage {
+ self.cond_var.wait(&mut v);
+ }
+ }
+ }
+}