From c52edc9bae22830a0dba4128cb81a2f1261f63e9 Mon Sep 17 00:00:00 2001
From: Edwin Wu <edwinwu@google.com>
Date: Tue, 16 Sep 2025 04:45:10 -0700
Subject: [PATCH] [NC Apple coverage] Refactor Apple CountDownLatch to use
 idiomatic absl::Mutex patterns.

PiperOrigin-RevId: 807644485
---
 .../platform/implementation/apple/count_down_latch.cc    | 4 ++--
 .../implementation/apple/count_down_latch_test.cc        | 9 +++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/internal/platform/implementation/apple/count_down_latch.cc b/internal/platform/implementation/apple/count_down_latch.cc
index 98c8de8f..69641502 100644
--- a/internal/platform/implementation/apple/count_down_latch.cc
+++ b/internal/platform/implementation/apple/count_down_latch.cc
@@ -26,9 +26,9 @@ Exception CountDownLatch::Await() {
 }
 
 ExceptionOr<bool> CountDownLatch::Await(absl::Duration timeout) {
-  bool condition = mutex_.LockWhenWithTimeout(
+  absl::MutexLock lock(&mutex_);
+  bool condition = mutex_.AwaitWithTimeout(
       absl::Condition(IsZeroOrNegative, &count_), timeout);
-  mutex_.Unlock();
   return ExceptionOr<bool>(condition);
 }
 
diff --git a/internal/platform/implementation/apple/count_down_latch_test.cc b/internal/platform/implementation/apple/count_down_latch_test.cc
index 77b655be..3b26af10 100644
--- a/internal/platform/implementation/apple/count_down_latch_test.cc
+++ b/internal/platform/implementation/apple/count_down_latch_test.cc
@@ -79,6 +79,15 @@ TEST(CountDownLatchTest, InitialCountNegativeAwaitDoesNotBlock) {
   EXPECT_TRUE(response.Ok());
 }
 
+TEST(CountDownLatchTest, CountDown) {
+  CountDownLatch latch(2);
+  latch.CountDown();
+  latch.CountDown();
+  auto response = latch.Await(absl::Milliseconds(100));
+  EXPECT_TRUE(response.ok());
+  EXPECT_TRUE(response.result());
+}
+
 }  // namespace
 }  // namespace apple
 }  // namespace nearby