Fix ProximityCheck so that re-entrant check calls callback.

This is a followup for I9083d6e87ad199099c117f00dcdc9e7e811435f5.
The test for re-entrant `check` calls, demonstrated that the original CL fixed the ConcurrentModificationException, but also that the check() callback was never invoked. Unregistering before the foreach fixes that.

Test: atest ProximityCheckTest
Flag: EXEMPT bugfix
Bug: 354293532
Change-Id: If4f6d0bd072b0aecf49e8b0e19e358a5a34409a4

2 files changed, 24 insertions, 2 deletions

diff --git a/packages/SystemUI/tests/src/com/android/systemui/util/sensors/ProximityCheckTest.java b/packages/SystemUI/multivalentTests/src/com/android/systemui/util/sensors/ProximityCheckTest.java
index 5dd008ac10f7..0eea120e4de0 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/util/sensors/ProximityCheckTest.java
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/util/sensors/ProximityCheckTest.java
@@ -74,6 +74,26 @@ public class ProximityCheckTest extends SysuiTestCase {
     }
 
     @Test
+    public void testRecursiveCheck() {
+        mProximityCheck.check(100, event-> mProximityCheck.check(100, mTestableCallback));
+
+        assertThat(mTestableCallback.mNumCalls).isEqualTo(0);
+        assertThat(mTestableCallback.mLastResult).isNull();
+
+        mFakeExecutor.advanceClockToNext();
+        mFakeExecutor.runAllReady();
+
+        assertThat(mTestableCallback.mNumCalls).isEqualTo(0);
+        assertThat(mTestableCallback.mLastResult).isNull();
+
+        mFakeProximitySensor.setLastEvent(new ThresholdSensorEvent(true, 0));
+        mFakeProximitySensor.alertListeners();
+
+        assertThat(mTestableCallback.mNumCalls).isEqualTo(1);
+        assertThat(mTestableCallback.mLastResult).isTrue();
+    }
+
+    @Test
     public void testTimeout() {
         mProximityCheck.check(100, mTestableCallback);
 
diff --git a/packages/SystemUI/src/com/android/systemui/util/sensors/ProximityCheck.java b/packages/SystemUI/src/com/android/systemui/util/sensors/ProximityCheck.java
index 373417b7bd68..5b9a6c556ec6 100644
--- a/packages/SystemUI/src/com/android/systemui/util/sensors/ProximityCheck.java
+++ b/packages/SystemUI/src/com/android/systemui/util/sensors/ProximityCheck.java
@@ -86,13 +86,15 @@ public class ProximityCheck implements Runnable {
     }
 
     private void onProximityEvent(ThresholdSensorEvent proximityEvent) {
+        // Move the callbacks to a local to avoid ConcurrentModificationException
         List<Consumer<Boolean>> oldCallbacks = mCallbacks;
         mCallbacks = new ArrayList<>();
+        // Unregister from the ProximitySensor to ensure a re-entrant check will re-register
+        unregister();
+        // Notify the callbacks
         oldCallbacks.forEach(
                 booleanConsumer ->
                         booleanConsumer.accept(
                                 proximityEvent == null ? null : proximityEvent.getBelow()));
-        unregister();
-        mRegistered.set(false);
     }
 }