From 1b355d8a87a3ad43bf240aa66b88eb98c1cd777f Mon Sep 17 00:00:00 2001 From: David Sherret Date: Wed, 5 Jun 2024 15:17:35 -0400 Subject: refactor(npm): improve locking around updating npm resolution (#24104) Introduces a `SyncReadAsyncWriteLock` to make it harder to write to the npm resolution without first waiting async in a queue. For the npm resolution, reading synchronously is fine, but when updating, someone should wait async, clone the data, then write the data at the end back. --- cli/util/sync/atomic_flag.rs | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) create mode 100644 cli/util/sync/atomic_flag.rs (limited to 'cli/util/sync/atomic_flag.rs') diff --git a/cli/util/sync/atomic_flag.rs b/cli/util/sync/atomic_flag.rs new file mode 100644 index 000000000..75396dcf4 --- /dev/null +++ b/cli/util/sync/atomic_flag.rs @@ -0,0 +1,35 @@ +// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license. + +use std::sync::atomic::AtomicBool; +use std::sync::atomic::Ordering; + +/// Simplifies the use of an atomic boolean as a flag. +#[derive(Debug, Default)] +pub struct AtomicFlag(AtomicBool); + +impl AtomicFlag { + /// Raises the flag returning if the raise was successful. + pub fn raise(&self) -> bool { + !self.0.swap(true, Ordering::SeqCst) + } + + /// Gets if the flag is raised. + pub fn is_raised(&self) -> bool { + self.0.load(Ordering::SeqCst) + } +} + +#[cfg(test)] +mod test { + use super::*; + + #[test] + fn atomic_flag_raises() { + let flag = AtomicFlag::default(); + assert!(!flag.is_raised()); // false by default + assert!(flag.raise()); + assert!(flag.is_raised()); + assert!(!flag.raise()); + assert!(flag.is_raised()); + } +} -- cgit v1.2.3