From c8588e3a0eb2497e6504f77bc4cbd062c6fe6613 Mon Sep 17 00:00:00 2001
From: Jan Tomljanovic <jtomljanovic@google.com>
Date: Wed, 11 Nov 2020 13:40:36 +0000
Subject: [PATCH] Limit the number of posted toasts by package to 5.

We consider posting a toast many seconds after it was triggered bad UX,
this change limits that behaviour.

Test: atest NotificationManagerServiceTest
Test: atest android.widget.cts.ToastTest
Bug: 171959286
Change-Id: I5d8cded37fbc9e5d4dca195436e1dff81c7f0e9e
---
 .../NotificationManagerService.java           |  7 +++--
 .../NotificationManagerServiceTest.java       | 26 +++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index 1516cded50a6a..1bcf1acae056f 100755
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -330,6 +330,9 @@ public class NotificationManagerService extends SystemService {
     static final int MAX_PACKAGE_NOTIFICATIONS = 50;
     static final float DEFAULT_MAX_NOTIFICATION_ENQUEUE_RATE = 5f;
 
+    // To limit bad UX of seeing a toast many seconds after if was triggered.
+    static final int MAX_PACKAGE_TOASTS = 5;
+
     // message codes
     static final int MESSAGE_DURATION_REACHED = 2;
     // 3: removed to a different handler
@@ -2945,8 +2948,8 @@ public class NotificationManagerService extends SystemService {
                             final ToastRecord r = mToastQueue.get(i);
                             if (r.pkg.equals(pkg)) {
                                 count++;
-                                if (count >= MAX_PACKAGE_NOTIFICATIONS) {
-                                    Slog.e(TAG, "Package has already posted " + count
+                                if (count >= MAX_PACKAGE_TOASTS) {
+                                    Slog.e(TAG, "Package has already queued " + count
                                             + " toasts. Not showing more. Package=" + pkg);
                                     return;
                                 }
diff --git a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
index 87aaba2b164a7..0b001688df0cf 100755
--- a/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
+++ b/services/tests/uiservicestests/src/com/android/server/notification/NotificationManagerServiceTest.java
@@ -5102,6 +5102,32 @@ public class NotificationManagerServiceTest extends UiServiceTestCase {
         assertEquals(1, mService.mToastQueue.size());
     }
 
+    @Test
+    public void testLimitNumberOfQueuedToastsFromPackage() throws Exception {
+        final String testPackage = "testPackageName";
+        assertEquals(0, mService.mToastQueue.size());
+        mService.isSystemUid = false;
+
+        // package is not suspended
+        when(mPackageManager.isPackageSuspendedForUser(testPackage, UserHandle.getUserId(mUid)))
+                .thenReturn(false);
+
+        INotificationManager nmService = (INotificationManager) mService.mService;
+
+        // Trying to quickly enqueue more toast than allowed.
+        for (int i = 0; i < NotificationManagerService.MAX_PACKAGE_TOASTS + 1; i++) {
+            nmService.enqueueTextToast(
+                    testPackage,
+                    new Binder(),
+                    "Text",
+                    /* duration */ 2000,
+                    /* displayId */ 0,
+                    /* callback */ null);
+        }
+        // Only allowed number enqueued, rest ignored.
+        assertEquals(NotificationManagerService.MAX_PACKAGE_TOASTS, mService.mToastQueue.size());
+    }
+
     private void setAppInForegroundForToasts(int uid, boolean inForeground) {
         int importance = (inForeground) ? IMPORTANCE_FOREGROUND : IMPORTANCE_NONE;
         when(mActivityManager.getUidImportance(mUid)).thenReturn(importance);