Add new UsageStats event DEVICE_STARTUP

As a counterpart to DEVICE_SHUTDOWN event, DEVICE_STARTUP records the
device startup event and timestamp.

Bug: 126529272
Test: adb shell dumpsys usagestats | grep DEVICE
Change-Id: Ia977658f9a1f701ad802dc943e9eff71171e9957

3 files changed, 30 insertions, 9 deletions

diff --git a/api/current.txt b/api/current.txt
index 12b4d4b29c84..dd6b29a8e9fc 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -7728,6 +7728,7 @@ package android.app.usage {
     field public static final int ACTIVITY_STOPPED = 23; // 0x17
     field public static final int CONFIGURATION_CHANGE = 5; // 0x5
     field public static final int DEVICE_SHUTDOWN = 26; // 0x1a
+    field public static final int DEVICE_STARTUP = 27; // 0x1b
     field public static final int FOREGROUND_SERVICE_START = 19; // 0x13
     field public static final int FOREGROUND_SERVICE_STOP = 20; // 0x14
     field public static final int KEYGUARD_HIDDEN = 18; // 0x12
diff --git a/core/java/android/app/usage/UsageEvents.java b/core/java/android/app/usage/UsageEvents.java
index 0d0e466e9688..b3d01fd68726 100644
--- a/core/java/android/app/usage/UsageEvents.java
+++ b/core/java/android/app/usage/UsageEvents.java
@@ -254,18 +254,32 @@ public final class UsageEvents implements Parcelable {
         public static final int FLUSH_TO_DISK = 25;
 
         /**
-         * An event type denoting that the device underwent a shutdown process.
+         * An event type denoting that the Android runtime underwent a shutdown process.
          * A DEVICE_SHUTDOWN event should be treated as if all started activities and foreground
          * services are now stopped and no explicit {@link #ACTIVITY_STOPPED} and
          * {@link #FOREGROUND_SERVICE_STOP} events will be generated for them.
+         *
+         * <p>The DEVICE_SHUTDOWN timestamp is actually the last time UsageStats database is
+         * persisted before the actual shutdown. Events (if there are any) between this timestamp
+         * and the actual shutdown is not persisted in the database. So any open events without
+         * matching close events between DEVICE_SHUTDOWN and {@link #DEVICE_STARTUP} should be
+         * ignored because the closing time is unknown.</p>
          */
         public static final int DEVICE_SHUTDOWN = 26;
 
         /**
+         * An event type denoting that the Android runtime started up. This could be after a
+         * shutdown or a runtime restart. Any open events without matching close events between
+         * {@link #DEVICE_SHUTDOWN} and DEVICE_STARTUP should be ignored because the closing time is
+         * unknown.
+         */
+        public static final int DEVICE_STARTUP = 27;
+
+        /**
          * Keep in sync with the greatest event type value.
          * @hide
          */
-        public static final int MAX_EVENT_TYPE = 26;
+        public static final int MAX_EVENT_TYPE = 27;
 
         /** @hide */
         public static final int FLAG_IS_PACKAGE_INSTANT_APP = 1 << 0;
diff --git a/services/usage/java/com/android/server/usage/UserUsageStatsService.java b/services/usage/java/com/android/server/usage/UserUsageStatsService.java
index b9a5676a84ef..9498e161ff61 100644
--- a/services/usage/java/com/android/server/usage/UserUsageStatsService.java
+++ b/services/usage/java/com/android/server/usage/UserUsageStatsService.java
@@ -17,6 +17,7 @@
 package com.android.server.usage;
 
 import static android.app.usage.UsageEvents.Event.DEVICE_SHUTDOWN;
+import static android.app.usage.UsageEvents.Event.DEVICE_STARTUP;
 import static android.app.usage.UsageStatsManager.INTERVAL_BEST;
 import static android.app.usage.UsageStatsManager.INTERVAL_COUNT;
 import static android.app.usage.UsageStatsManager.INTERVAL_DAILY;
@@ -137,15 +138,18 @@ class UserUsageStatsService {
 
         // During system reboot, add a DEVICE_SHUTDOWN event to the end of event list, the timestamp
         // is last time UsageStatsDatabase is persisted to disk.
+        // Also add a DEVICE_STARTUP event with current system timestamp.
         final IntervalStats currentDailyStats = mCurrentStats[INTERVAL_DAILY];
         if (currentDailyStats != null) {
-            final int size = currentDailyStats.events.size();
-            if (size == 0 || currentDailyStats.events.get(size - 1).mEventType != DEVICE_SHUTDOWN) {
-                // The last event in event list is not DEVICE_SHUTDOWN, then we insert one.
-                final Event event = new Event(DEVICE_SHUTDOWN, currentDailyStats.lastTimeSaved);
-                event.mPackage = Event.DEVICE_EVENT_PACKAGE_NAME;
-                currentDailyStats.addEvent(event);
-            }
+            // File system timestamp only has precision of 1 second, add 1000ms to make up
+            // for the loss of round up.
+            final Event shutdownEvent =
+                    new Event(DEVICE_SHUTDOWN, currentDailyStats.lastTimeSaved + 1000);
+            shutdownEvent.mPackage = Event.DEVICE_EVENT_PACKAGE_NAME;
+            currentDailyStats.addEvent(shutdownEvent);
+            final Event startupEvent = new Event(DEVICE_STARTUP, currentTimeMillis);
+            startupEvent.mPackage = Event.DEVICE_EVENT_PACKAGE_NAME;
+            currentDailyStats.addEvent(startupEvent);
         }
 
         if (mDatabase.isNewUpdate()) {
@@ -956,6 +960,8 @@ class UserUsageStatsService {
                 return "KEYGUARD_HIDDEN";
             case Event.DEVICE_SHUTDOWN:
                 return "DEVICE_SHUTDOWN";
+            case Event.DEVICE_STARTUP:
+                return "DEVICE_STARTUP";
             default:
                 return "UNKNOWN_TYPE_" + eventType;
         }