1 files changed, 126 insertions, 0 deletions
diff --git a/java/com/android/dialer/notification/NotificationThrottler.java b/java/com/android/dialer/notification/NotificationThrottler.java
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+++ b/java/com/android/dialer/notification/NotificationThrottler.java
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+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License
+ */
+
+package com.android.dialer.notification;
+
+import android.app.Notification;
+import android.app.NotificationManager;
+import android.content.Context;
+import android.service.notification.StatusBarNotification;
+import android.support.annotation.NonNull;
+import android.text.TextUtils;
+import com.android.dialer.common.Assert;
+import com.android.dialer.common.LogUtil;
+import com.android.dialer.logging.DialerImpression;
+import com.android.dialer.logging.Logger;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.List;
+
+/**
+ * Utility to ensure that only a certain number of notifications are shown for a particular
+ * notification type. Once the limit is reached, older notifications are cancelled.
+ */
+/* package */ class NotificationThrottler {
+  /**
+   * For gropued bundled notifications, the system UI will only display the last 8. For grouped
+   * unbundled notifications, the system displays all notifications until a global maximum of 50 is
+   * reached.
+   */
+  private static final int MAX_NOTIFICATIONS_PER_TAG = 10;
+
+  private static final int HIGH_GLOBAL_NOTIFICATION_COUNT = 45;
+
+  private static boolean didLogHighGlobalNotificationCountReached;
+
+  /* package */ static void throttle(@NonNull Context context, @NonNull Notification notification) {
+    Assert.isNotNull(context);
+    Assert.isNotNull(notification);
+
+    // No limiting for non-grouped notifications.
+    String groupKey = notification.getGroup();
+    if (TextUtils.isEmpty(groupKey)) {
+      return;
+    }
+
+    NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
+    StatusBarNotification[] activeNotifications = notificationManager.getActiveNotifications();
+    if (activeNotifications.length > HIGH_GLOBAL_NOTIFICATION_COUNT
+        && !didLogHighGlobalNotificationCountReached) {
+      LogUtil.i(
+          "NotificationThrottler.throttle",
+          "app has %d notifications, system may suppress future notifications",
+          activeNotifications.length);
+      didLogHighGlobalNotificationCountReached = true;
+      Logger.get(context)
+          .logImpression(DialerImpression.Type.HIGH_GLOBAL_NOTIFICATION_COUNT_REACHED);
+    }
+
+    // Count the number of notificatons for this group (excluding the summary).
+    int count = 0;
+    for (StatusBarNotification currentNotification : activeNotifications) {
+      if (isNotificationInGroup(currentNotification, groupKey)) {
+        count++;
+      }
+    }
+
+    if (count > MAX_NOTIFICATIONS_PER_TAG) {
+      LogUtil.i(
+          "NotificationThrottler.throttle",
+          "groupKey: %s is over limit, count: %d, limit: %d",
+          groupKey,
+          count,
+          MAX_NOTIFICATIONS_PER_TAG);
+      List<StatusBarNotification> notifications = getSortedMatchingNotifications(context, groupKey);
+      for (int i = 0; i < (count - MAX_NOTIFICATIONS_PER_TAG); i++) {
+        notificationManager.cancel(notifications.get(i).getTag(), notifications.get(i).getId());
+      }
+    }
+  }
+
+  private static List<StatusBarNotification> getSortedMatchingNotifications(
+      @NonNull Context context, @NonNull String groupKey) {
+    List<StatusBarNotification> notifications = new ArrayList<>();
+    NotificationManager notificationManager = context.getSystemService(NotificationManager.class);
+    for (StatusBarNotification notification : notificationManager.getActiveNotifications()) {
+      if (isNotificationInGroup(notification, groupKey)) {
+        notifications.add(notification);
+      }
+    }
+    Collections.sort(
+        notifications,
+        new Comparator<StatusBarNotification>() {
+          @Override
+          public int compare(StatusBarNotification left, StatusBarNotification right) {
+            return Long.compare(left.getPostTime(), right.getPostTime());
+          }
+        });
+    return notifications;
+  }
+
+  private static boolean isNotificationInGroup(
+      @NonNull StatusBarNotification notification, @NonNull String groupKey) {
+    // Don't include group summaries.
+    if ((notification.getNotification().flags & Notification.FLAG_GROUP_SUMMARY) != 0) {
+      return false;
+    }
+
+    return TextUtils.equals(groupKey, notification.getNotification().getGroup());
+  }
+
+  private NotificationThrottler() {}
+}