Don't create a file with empty favorites

A file could be created with empty favorites, preventing a late restore
(from D2D) from overwriting it.

Test: atest ControlsFavoritePersistenceWrapperTest
Test: manual D2d restore
Bug: 165200632
Change-Id: Ia99b8e98e4f62d8d0c7385c820c645f3aaabe6f3

2 files changed, 16 insertions, 0 deletions

diff --git a/packages/SystemUI/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapper.kt b/packages/SystemUI/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapper.kt
index 1bda841d4a63..d930c98cabe1 100644
--- a/packages/SystemUI/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapper.kt
+++ b/packages/SystemUI/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapper.kt
@@ -87,6 +87,10 @@ class ControlsFavoritePersistenceWrapper(
      * @param list a list of favorite controls. The list will be stored in the same order.
      */
     fun storeFavorites(structures: List<StructureInfo>) {
+        if (structures.isEmpty() && !file.exists()) {
+            // Do not create a new file to store nothing
+            return
+        }
         executor.execute {
             Log.d(TAG, "Saving data to file: $file")
             val atomicFile = AtomicFile(file)
diff --git a/packages/SystemUI/tests/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapperTest.kt b/packages/SystemUI/tests/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapperTest.kt
index 861c6207f5b0..690b9a7248be 100644
--- a/packages/SystemUI/tests/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapperTest.kt
+++ b/packages/SystemUI/tests/src/com/android/systemui/controls/controller/ControlsFavoritePersistenceWrapperTest.kt
@@ -25,6 +25,7 @@ import com.android.systemui.util.concurrency.FakeExecutor
 import com.android.systemui.util.time.FakeSystemClock
 import org.junit.After
 import org.junit.Assert.assertEquals
+import org.junit.Assert.assertFalse
 import org.junit.Before
 import org.junit.Test
 import org.junit.runner.RunWith
@@ -78,4 +79,15 @@ class ControlsFavoritePersistenceWrapperTest : SysuiTestCase() {
 
         assertEquals(list, wrapper.readFavorites())
     }
+
+    @Test
+    fun testSaveEmptyOnNonExistingFile() {
+        if (file.exists()) {
+            file.delete()
+        }
+
+        wrapper.storeFavorites(emptyList())
+
+        assertFalse(file.exists())
+    }
 }