Eagerly initialize BMS in Trampoline's constructor

After multi-user BMS became a lightweight class as well, so no need to
lazily initialize it. This lays the ground for unifying Trampoline and
BMS.

Test: atest TrampolineTest
Test: adb shell bmgr backupnow <package>
Bug: 135247112
Bug: 135661048
Change-Id: Ia7f69d2ed282c6dfe6443a601f27229d43802fe6

2 files changed, 80 insertions, 76 deletions

diff --git a/services/backup/java/com/android/server/backup/BackupManagerService.java b/services/backup/java/com/android/server/backup/BackupManagerService.java
index d5a7c818bfb2..814f6daac43c 100644
--- a/services/backup/java/com/android/server/backup/BackupManagerService.java
+++ b/services/backup/java/com/android/server/backup/BackupManagerService.java
@@ -195,16 +195,20 @@ public class BackupManagerService {
     }
 
     boolean isAbleToServeUser(int userId) {
-        return getServiceUsers().get(UserHandle.USER_SYSTEM) != null
-                && getServiceUsers().get(userId) != null;
+        return getUserServices().get(UserHandle.USER_SYSTEM) != null
+                && getUserServices().get(userId) != null;
     }
 
     /**
-     *  Returns a lst of users currently unlocked that have a
-     *  {@link UserBackupManagerService} registered.
+     *  Returns a list of users currently unlocked that have a {@link UserBackupManagerService}
+     *  registered.
+     *
+     *  Warning: Do NOT modify returned object as it's used inside.
+     *
+     *  TODO: Return a copy or only expose read-only information through other means.
      */
     @VisibleForTesting
-    public SparseArray<UserBackupManagerService> getServiceUsers() {
+    public SparseArray<UserBackupManagerService> getUserServices() {
         return mServiceUsers;
     }
 
@@ -495,7 +499,8 @@ public class BackupManagerService {
 
     /**
      * Returns a {@link UserHandle} for the user that has {@code ancestralSerialNumber} as the
-     * serial number of the its ancestral work profile.
+     * serial number of the its ancestral work profile or null if there is no {@link
+     * UserBackupManagerService} associated with that user.
      *
      * <p> The ancestral work profile is set by {@link #setAncestralSerialNumber(long)}
      * and it corresponds to the profile that was used to restore to the callers profile.
@@ -504,16 +509,18 @@ public class BackupManagerService {
     public UserHandle getUserForAncestralSerialNumber(long ancestralSerialNumber) {
         int callingUserId = Binder.getCallingUserHandle().getIdentifier();
         long oldId = Binder.clearCallingIdentity();
-        int[] userIds;
+        final int[] userIds;
         try {
-            userIds = mContext.getSystemService(UserManager.class).getProfileIds(callingUserId,
-                    false);
+            userIds =
+                    mContext
+                            .getSystemService(UserManager.class)
+                            .getProfileIds(callingUserId, false);
         } finally {
             Binder.restoreCallingIdentity(oldId);
         }
 
         for (int userId : userIds) {
-            UserBackupManagerService userBackupManagerService = getServiceUsers().get(userId);
+            UserBackupManagerService userBackupManagerService = getUserServices().get(userId);
             if (userBackupManagerService != null) {
                 if (userBackupManagerService.getAncestralSerialNumber() == ancestralSerialNumber) {
                     return UserHandle.of(userId);
@@ -880,28 +887,35 @@ public class BackupManagerService {
     }
 
     /** Implementation to receive lifecycle event callbacks for system services. */
-    public static final class Lifecycle extends SystemService {
+    public static class Lifecycle extends SystemService {
         public Lifecycle(Context context) {
+            this(context, new Trampoline(context));
+        }
+
+        @VisibleForTesting
+        Lifecycle(Context context, Trampoline trampoline) {
             super(context);
-            sInstance = new Trampoline(context);
+            sInstance = trampoline;
         }
 
         @Override
         public void onStart() {
-            publishBinderService(Context.BACKUP_SERVICE, sInstance);
+            publishService(Context.BACKUP_SERVICE, sInstance);
         }
 
         @Override
         public void onUnlockUser(int userId) {
-            if (userId == UserHandle.USER_SYSTEM) {
-                sInstance.initializeService();
-            }
-            sInstance.unlockUser(userId);
+            sInstance.onUnlockUser(userId);
         }
 
         @Override
         public void onStopUser(int userId) {
-            sInstance.stopUser(userId);
+            sInstance.onStopUser(userId);
+        }
+
+        @VisibleForTesting
+        void publishService(String name, IBinder service) {
+            publishBinderService(name, service);
         }
     }
 }
diff --git a/services/backup/java/com/android/server/backup/Trampoline.java b/services/backup/java/com/android/server/backup/Trampoline.java
index f4b66456c27b..210a9ef94e53 100644
--- a/services/backup/java/com/android/server/backup/Trampoline.java
+++ b/services/backup/java/com/android/server/backup/Trampoline.java
@@ -40,12 +40,12 @@ import android.os.ParcelFileDescriptor;
 import android.os.Process;
 import android.os.RemoteException;
 import android.os.SystemProperties;
-import android.os.Trace;
 import android.os.UserHandle;
 import android.os.UserManager;
 import android.util.Slog;
 
 import com.android.internal.annotations.GuardedBy;
+import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.DumpUtils;
 import com.android.server.backup.utils.RandomAccessFileUtils;
 
@@ -73,9 +73,6 @@ import java.io.PrintWriter;
  * Temporary disabling is controlled by {@link #setBackupServiceActive(int, boolean)} through
  * privileged callers (currently {@link DevicePolicyManager}). This is called on {@link
  * UserHandle#USER_SYSTEM} and disables backup for all users.
- *
- * <p>Creation of the backup service is done when {@link UserHandle#USER_SYSTEM} is unlocked. The
- * system user is unlocked before any other users.
  */
 public class Trampoline extends IBackupManager.Stub {
     /**
@@ -109,7 +106,10 @@ public class Trampoline extends IBackupManager.Stub {
     // TODD(b/121198006): remove this object and synchronized all methods on "this".
     private final Object mStateLock = new Object();
 
-    private volatile BackupManagerService mService;
+    // TODO: This is not marked as final because of test code. Since we'll merge BMS and Trampoline,
+    // it doesn't make sense to refactor for final. It's never null.
+    @VisibleForTesting
+    protected volatile BackupManagerService mService;
     private final Handler mHandler;
 
     public Trampoline(Context context) {
@@ -120,6 +120,13 @@ public class Trampoline extends IBackupManager.Stub {
         handlerThread.start();
         mHandler = new Handler(handlerThread.getLooper());
         mUserManager = UserManager.get(context);
+        mService = new BackupManagerService(mContext, this);
+    }
+
+    // TODO: Remove this when we implement DI by injecting in the construtor.
+    @VisibleForTesting
+    Handler getBackupHandler() {
+        return mHandler;
     }
 
     protected boolean isBackupDisabled() {
@@ -205,7 +212,7 @@ public class Trampoline extends IBackupManager.Stub {
     // This method should not perform any I/O (e.g. do not call isBackupActivatedForUser),
     // it's used in multiple places where I/O waits would cause system lock-ups.
     private boolean isUserReadyForBackup(int userId) {
-        return mService != null && mService.isAbleToServeUser(userId);
+        return mService.isAbleToServeUser(userId);
     }
 
     /**
@@ -230,68 +237,55 @@ public class Trampoline extends IBackupManager.Stub {
         return mUserManager;
     }
 
-    protected BackupManagerService createBackupManagerService() {
-        return new BackupManagerService(mContext, this);
-    }
-
     protected void postToHandler(Runnable runnable) {
         mHandler.post(runnable);
     }
 
     /**
-     * Called from {@link BackupManagerService.Lifecycle} when the system user is unlocked. Attempts
-     * to initialize {@link BackupManagerService}. Offloads work onto the handler thread {@link
-     * #mHandlerThread} to keep unlock time low.
-     */
-    void initializeService() {
-        postToHandler(
-                () -> {
-                    Trace.traceBegin(Trace.TRACE_TAG_ACTIVITY_MANAGER, "backup init");
-                    if (mGlobalDisable) {
-                        Slog.i(TAG, "Backup service not supported");
-                        return;
-                    }
-                    synchronized (mStateLock) {
-                        if (mService == null) {
-                            mService = createBackupManagerService();
-                        }
-                    }
-                    Trace.traceEnd(Trace.TRACE_TAG_ACTIVITY_MANAGER);
-                });
-    }
-
-    /**
      * Called from {@link BackupManagerService.Lifecycle} when a user {@code userId} is unlocked.
      * Starts the backup service for this user if backup is active for this user. Offloads work onto
-     * the handler thread {@link #mHandlerThread} to keep unlock time low.
+     * the handler thread {@link #mHandlerThread} to keep unlock time low since backup is not
+     * essential for device functioning.
      */
-    void unlockUser(int userId) {
+    void onUnlockUser(int userId) {
         postToHandler(() -> startServiceForUser(userId));
     }
 
     private void startServiceForUser(int userId) {
         // We know that the user is unlocked here because it is called from setBackupServiceActive
         // and unlockUser which have these guarantees. So we can check if the file exists.
-        if (mService != null && isBackupActivatedForUser(userId)) {
-            Slog.i(TAG, "Starting service for user: " + userId);
-            mService.startServiceForUser(userId);
+        if (mGlobalDisable) {
+            Slog.i(TAG, "Backup service not supported");
+            return;
         }
+        if (!isBackupActivatedForUser(userId)) {
+            Slog.i(TAG, "Backup not activated for user " + userId);
+            return;
+        }
+        Slog.i(TAG, "Starting service for user: " + userId);
+        mService.startServiceForUser(userId);
     }
 
     /**
      * Called from {@link BackupManagerService.Lifecycle} when a user {@code userId} is stopped.
      * Offloads work onto the handler thread {@link #mHandlerThread} to keep stopping time low.
      */
-    void stopUser(int userId) {
+    void onStopUser(int userId) {
         postToHandler(
                 () -> {
-                    if (mService != null) {
+                    if (!mGlobalDisable) {
                         Slog.i(TAG, "Stopping service for user: " + userId);
                         mService.stopServiceForUser(userId);
                     }
                 });
     }
 
+    /** Returns {@link UserBackupManagerService} for user {@code userId}. */
+    @Nullable
+    public UserBackupManagerService getUserService(int userId) {
+        return mService.getUserServices().get(userId);
+    }
+
     /**
      * The system user and managed profiles can only be acted on by callers in the system or root
      * processes. Other users can be acted on by callers who have both android.permission.BACKUP and
@@ -350,9 +344,6 @@ public class Trampoline extends IBackupManager.Stub {
         synchronized (mStateLock) {
             Slog.i(TAG, "Making backup " + (makeActive ? "" : "in") + "active");
             if (makeActive) {
-                if (mService == null) {
-                    mService = createBackupManagerService();
-                }
                 try {
                     activateBackupForUserLocked(userId);
                 } catch (IOException e) {
@@ -380,7 +371,7 @@ public class Trampoline extends IBackupManager.Stub {
                 }
                 //TODO(b/121198006): loop through active users that have work profile and
                 // stop them as well.
-                stopUser(userId);
+                onStopUser(userId);
             }
         }
     }
@@ -388,8 +379,7 @@ public class Trampoline extends IBackupManager.Stub {
     // IBackupManager binder API
 
     /**
-     * Querying activity state of backup service. Calling this method before initialize yields
-     * undefined result.
+     * Querying activity state of backup service.
      *
      * @param userId The user in which the activity state of backup service is queried.
      * @return true if the service is active.
@@ -397,7 +387,7 @@ public class Trampoline extends IBackupManager.Stub {
     @Override
     public boolean isBackupServiceActive(int userId) {
         synchronized (mStateLock) {
-            return mService != null && isBackupActivatedForUser(userId);
+            return !mGlobalDisable && isBackupActivatedForUser(userId);
         }
     }
 
@@ -598,8 +588,8 @@ public class Trampoline extends IBackupManager.Stub {
     @Override
     @Nullable
     public ComponentName getCurrentTransportComponentForUser(int userId) {
-        return (isUserReadyForBackup(userId)) ? mService.getCurrentTransportComponent(userId)
-                : null;
+        return (isUserReadyForBackup(userId))
+                ? mService.getCurrentTransportComponent(userId) : null;
     }
 
     @Override
@@ -614,8 +604,8 @@ public class Trampoline extends IBackupManager.Stub {
 
     @Override
     public ComponentName[] listAllTransportComponentsForUser(int userId) throws RemoteException {
-        return (isUserReadyForBackup(userId)) ? mService.listAllTransportComponents(userId)
-                : null;
+        return (isUserReadyForBackup(userId))
+                ? mService.listAllTransportComponents(userId) : null;
     }
 
     @Override
@@ -648,8 +638,8 @@ public class Trampoline extends IBackupManager.Stub {
     @Override
     public String selectBackupTransportForUser(int userId, String transport)
             throws RemoteException {
-        return (isUserReadyForBackup(userId)) ? mService.selectBackupTransport(userId, transport)
-                : null;
+        return (isUserReadyForBackup(userId))
+                ? mService.selectBackupTransport(userId, transport) : null;
     }
 
     @Override
@@ -700,8 +690,8 @@ public class Trampoline extends IBackupManager.Stub {
     @Override
     public Intent getDataManagementIntentForUser(int userId, String transport)
             throws RemoteException {
-        return isUserReadyForBackup(userId) ? mService.getDataManagementIntent(userId, transport)
-                : null;
+        return isUserReadyForBackup(userId)
+                ? mService.getDataManagementIntent(userId, transport) : null;
     }
 
     @Override
@@ -784,15 +774,15 @@ public class Trampoline extends IBackupManager.Stub {
 
     @Override
     @Nullable public UserHandle getUserForAncestralSerialNumber(long ancestralSerialNumber) {
-        if (mService != null) {
-            return mService.getUserForAncestralSerialNumber(ancestralSerialNumber);
+        if (mGlobalDisable) {
+            return null;
         }
-        return null;
+        return mService.getUserForAncestralSerialNumber(ancestralSerialNumber);
     }
 
     @Override
     public void setAncestralSerialNumber(long ancestralSerialNumber) {
-        if (mService != null) {
+        if (!mGlobalDisable) {
             mService.setAncestralSerialNumber(ancestralSerialNumber);
         }
     }