1 files changed, 45 insertions, 7 deletions

diff --git a/src/collection/retry.rs b/src/collection/retry.rs
index b9ac530..1cce663 100755
--- a/src/collection/retry.rs
+++ b/src/collection/retry.rs
@@ -1,5 +1,6 @@
-use std::cell::Cell;
-use std::collections::HashSet;
+use core::cell::Cell;
+
+use alloc::vec::Vec;
 
 use crate::collection::utils;
 use crate::handle_unwind::handle_unwind;
@@ -14,6 +15,20 @@ use super::utils::{
 };
 use super::{LockGuard, RetryingLockCollection};
 
+cfg_select! {
+	feature = "std" => {
+		fn set_with_capacity<T>(capacity: usize) -> std::collections::HashSet<T> {
+			std::collections::HashSet::with_capacity(capacity)
+		}
+	},
+	_ => {
+		#[expect(clippy::missing_const_for_fn)]
+		fn set_with_capacity<T>(_capacity: usize) -> alloc::collections::btree_set::BTreeSet<T> {
+			alloc::collections::btree_set::BTreeSet::new()
+		}
+	},
+}
+
 /// Checks that a collection contains no duplicate references to a lock.
 fn contains_duplicates<L: Lockable>(data: L) -> bool {
 	let mut locks = Vec::new();
@@ -21,7 +36,7 @@ fn contains_duplicates<L: Lockable>(data: L) -> bool {
 	// cast to *const () so that the v-table pointers are not used for hashing
 	let locks = locks.into_iter().map(|l| (&raw const *l).cast::<()>());
 
-	let mut locks_set = HashSet::with_capacity(locks.len());
+	let mut locks_set = set_with_capacity(locks.len());
 	for lock in locks {
 		if !locks_set.insert(lock) {
 			return true;
@@ -1004,9 +1019,14 @@ where
 
 #[cfg(test)]
 mod tests {
+	use alloc::vec;
+
 	use super::*;
+	#[cfg(feature = "std")]
 	use crate::collection::BoxedLockCollection;
-	use crate::{Mutex, RwLock, ThreadKey};
+	#[cfg(feature = "std")]
+	use crate::ThreadKey;
+	use crate::{Mutex, RwLock};
 
 	#[test]
 	fn nonduplicate_lock_references_are_allowed() {
@@ -1033,6 +1053,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn from() {
 		let key = ThreadKey::get().unwrap();
 		let collection =
@@ -1044,6 +1065,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn new_ref_works() {
 		let key = ThreadKey::get().unwrap();
 		let mutexes = [Mutex::new(0), Mutex::new(1)];
@@ -1055,6 +1077,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn scoped_read_sees_changes() {
 		let mut key = ThreadKey::get().unwrap();
 		let mutexes = [RwLock::new(24), RwLock::new(42)];
@@ -1071,6 +1094,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn get_mut_affects_scoped_read() {
 		let mut key = ThreadKey::get().unwrap();
 		let mutexes = [RwLock::new(24), RwLock::new(42)];
@@ -1088,6 +1112,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn scoped_try_lock_can_fail() {
 		let key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([Mutex::new(1), Mutex::new(2)]);
@@ -1105,6 +1130,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn scoped_try_read_can_fail() {
 		let key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([RwLock::new(1), RwLock::new(2)]);
@@ -1122,6 +1148,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn try_lock_works() {
 		let key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([Mutex::new(1), Mutex::new(2)]);
@@ -1139,6 +1166,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn try_read_works() {
 		let key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([RwLock::new(1), RwLock::new(2)]);
@@ -1156,6 +1184,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn try_read_fails_for_locked_collection() {
 		let key = ThreadKey::get().unwrap();
 		let mutexes = [RwLock::new(24), RwLock::new(42)];
@@ -1166,7 +1195,7 @@ mod tests {
 				let key = ThreadKey::get().unwrap();
 				let guard = mutexes[1].write(key);
 				assert_eq!(*guard, 42);
-				std::mem::forget(guard);
+				core::mem::forget(guard);
 			});
 		});
 
@@ -1175,6 +1204,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn locks_all_inner_mutexes() {
 		let key = ThreadKey::get().unwrap();
 		let mutex1 = Mutex::new(0);
@@ -1190,6 +1220,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn locks_all_inner_rwlocks() {
 		let key = ThreadKey::get().unwrap();
 		let rwlock1 = RwLock::new(0);
@@ -1205,6 +1236,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn works_with_other_collections() {
 		let key = ThreadKey::get().unwrap();
 		let mutex1 = Mutex::new(0);
@@ -1222,6 +1254,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn from_iterator() {
 		let key = ThreadKey::get().unwrap();
 		let collection: RetryingLockCollection<Vec<Mutex<&str>>> =
@@ -1243,6 +1276,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn into_ref_iterator() {
 		let mut key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([Mutex::new(0), Mutex::new(1), Mutex::new(2)]);
@@ -1252,6 +1286,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn ref_iterator() {
 		let mut key = ThreadKey::get().unwrap();
 		let collection = RetryingLockCollection::new([Mutex::new(0), Mutex::new(1), Mutex::new(2)]);
@@ -1261,6 +1296,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn mut_iterator() {
 		let mut key = ThreadKey::get().unwrap();
 		let mut collection =
@@ -1282,6 +1318,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn lock_empty_lock_collection() {
 		let key = ThreadKey::get().unwrap();
 		let collection: RetryingLockCollection<[RwLock<i32>; 0]> = RetryingLockCollection::new([]);
@@ -1295,6 +1332,7 @@ mod tests {
 	}
 
 	#[test]
+	#[cfg(feature = "std")]
 	fn read_empty_lock_collection() {
 		let key = ThreadKey::get().unwrap();
 		let collection: RetryingLockCollection<[RwLock<i32>; 0]> = RetryingLockCollection::new([]);
@@ -1312,7 +1350,7 @@ mod tests {
 		let mutexes = [Mutex::new(0), Mutex::new(1)];
 		let collection = RetryingLockCollection::new_ref(&mutexes);
 
-		assert!(std::ptr::addr_eq(&raw const mutexes, collection.as_ref()))
+		assert!(core::ptr::addr_eq(&raw const mutexes, collection.as_ref()))
 	}
 
 	#[test]
@@ -1330,7 +1368,7 @@ mod tests {
 		let mutexes = [Mutex::new(0), Mutex::new(1)];
 		let collection = RetryingLockCollection::new_ref(&mutexes);
 
-		assert!(std::ptr::addr_eq(&raw const mutexes, *collection.child()))
+		assert!(core::ptr::addr_eq(&raw const mutexes, *collection.child()))
 	}
 
 	#[test]