Wrap some services into a SystemService

These services can now be excluded by modifying the list of REQUIRED_SERVICES (TB renamed)

Changed appwidget, devicepolicy, backup and print services.

Change-Id: Id8e2855d5c045cd57bdb02dca9ed75172803bce7

1 files changed, 528 insertions, 494 deletions

diff --git a/services/print/java/com/android/server/print/PrintManagerService.java b/services/print/java/com/android/server/print/PrintManagerService.java
index 98acc27..852736b 100644
--- a/services/print/java/com/android/server/print/PrintManagerService.java
+++ b/services/print/java/com/android/server/print/PrintManagerService.java
@@ -51,6 +51,8 @@ import android.util.SparseArray;
 import com.android.internal.R;
 import com.android.internal.content.PackageMonitor;
 import com.android.internal.os.BackgroundThread;
+import com.android.server.SystemService;
+import com.android.server.devicepolicy.DevicePolicyManagerService;
 
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
@@ -58,599 +60,631 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
-public final class PrintManagerService extends IPrintManager.Stub {
-
-    private static final char COMPONENT_NAME_SEPARATOR = ':';
-
-    private static final String EXTRA_PRINT_SERVICE_COMPONENT_NAME =
-            "EXTRA_PRINT_SERVICE_COMPONENT_NAME";
-
-    private final Object mLock = new Object();
-
-    private final Context mContext;
-
-    private final SparseArray<UserState> mUserStates = new SparseArray<UserState>();
+/**
+ * SystemService wrapper for the PrintManager implementation. Publishes
+ * Context.PRINT_SERVICE.
+ * PrintManager implementation is contained within.
+ */
 
-    private int mCurrentUserId = UserHandle.USER_OWNER;
+public final class PrintManagerService extends SystemService {
 
-    public PrintManagerService(Context context) {
-        mContext = context;
-        registerContentObservers();
-        registerBoradcastReceivers();
-    }
-
-    public void systemRuning() {
-        BackgroundThread.getHandler().post(new Runnable() {
-            @Override
-            public void run() {
-                final UserState userState;
-                synchronized (mLock) {
-                    userState = getCurrentUserStateLocked();
-                    userState.updateIfNeededLocked();
-                }
-                // This is the first time we switch to this user after boot, so
-                // now is the time to remove obsolete print jobs since they
-                // are from the last boot and no application would query them.
-                userState.removeObsoletePrintJobs();
-            }
-        });
-    }
+    private PrintManagerImpl mPrintManagerImpl;
 
     @Override
-    public Bundle print(String printJobName, IPrintDocumentAdapter adapter,
-            PrintAttributes attributes, String packageName, int appId, int userId) {
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        String resolvedPackageName = resolveCallingPackageNameEnforcingSecurity(packageName);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            return userState.print(printJobName, adapter, attributes,
-                    resolvedPackageName, resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
+    public void onCreate(Context context) {
+        mPrintManagerImpl = new PrintManagerImpl(context);
     }
-
     @Override
-    public List<PrintJobInfo> getPrintJobInfos(int appId, int userId) {
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            return userState.getPrintJobInfos(resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
+    public void onStart() {
+        publishBinderService(Context.PRINT_SERVICE, mPrintManagerImpl);
     }
 
     @Override
-    public PrintJobInfo getPrintJobInfo(PrintJobId printJobId, int appId, int userId) {
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            return userState.getPrintJobInfo(printJobId, resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+    public void onBootPhase(int phase) {
+        if (phase == PHASE_THIRD_PARTY_APPS_CAN_START) {
+            mPrintManagerImpl.systemRunning();
         }
     }
 
-    @Override
-    public void cancelPrintJob(PrintJobId printJobId, int appId, int userId) {
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.cancelPrintJob(printJobId, resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
-    }
+    class PrintManagerImpl extends IPrintManager.Stub {
+        private static final char COMPONENT_NAME_SEPARATOR = ':';
 
-    @Override
-    public void restartPrintJob(PrintJobId printJobId, int appId, int userId) {
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.restartPrintJob(printJobId, resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
-    }
+        private static final String EXTRA_PRINT_SERVICE_COMPONENT_NAME =
+                "EXTRA_PRINT_SERVICE_COMPONENT_NAME";
 
-    @Override
-    public List<PrintServiceInfo> getEnabledPrintServices(int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            return userState.getEnabledPrintServices();
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
-    }
+        private final Object mLock = new Object();
 
-    @Override
-    public List<PrintServiceInfo> getInstalledPrintServices(int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            return userState.getInstalledPrintServices();
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
-    }
+        private final Context mContext;
 
-    @Override
-    public void createPrinterDiscoverySession(IPrinterDiscoveryObserver observer,
-            int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.createPrinterDiscoverySession(observer);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
-        }
-    }
+        private final SparseArray<UserState> mUserStates = new SparseArray<UserState>();
 
-    @Override
-    public void destroyPrinterDiscoverySession(IPrinterDiscoveryObserver observer,
-            int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
-        }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.destroyPrinterDiscoverySession(observer);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+        private int mCurrentUserId = UserHandle.USER_OWNER;
+
+        PrintManagerImpl(Context context) {
+            mContext = context;
+            registerContentObservers();
+            registerBoradcastReceivers();
         }
-    }
 
-    @Override
-    public void startPrinterDiscovery(IPrinterDiscoveryObserver observer,
-            List<PrinterId> priorityList, int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        public void systemRunning() {
+            BackgroundThread.getHandler().post(new Runnable() {
+                @Override
+                public void run() {
+                    final UserState userState;
+                    synchronized (mLock) {
+                        userState = getCurrentUserStateLocked();
+                        userState.updateIfNeededLocked();
+                    }
+                    // This is the first time we switch to this user after boot, so
+                    // now is the time to remove obsolete print jobs since they
+                    // are from the last boot and no application would query them.
+                    userState.removeObsoletePrintJobs();
+                }
+            });
+        }
+
+        @Override
+        public Bundle print(String printJobName, IPrintDocumentAdapter adapter,
+                PrintAttributes attributes, String packageName, int appId, int userId) {
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            String resolvedPackageName = resolveCallingPackageNameEnforcingSecurity(packageName);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                return userState.print(printJobName, adapter, attributes,
+                        resolvedPackageName, resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.startPrinterDiscovery(observer, priorityList);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public List<PrintJobInfo> getPrintJobInfos(int appId, int userId) {
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                return userState.getPrintJobInfos(resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void stopPrinterDiscovery(IPrinterDiscoveryObserver observer, int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public PrintJobInfo getPrintJobInfo(PrintJobId printJobId, int appId, int userId) {
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                return userState.getPrintJobInfo(printJobId, resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.stopPrinterDiscovery(observer);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public void cancelPrintJob(PrintJobId printJobId, int appId, int userId) {
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.cancelPrintJob(printJobId, resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void validatePrinters(List<PrinterId> printerIds, int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public void restartPrintJob(PrintJobId printJobId, int appId, int userId) {
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.restartPrintJob(printJobId, resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.validatePrinters(printerIds);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public List<PrintServiceInfo> getEnabledPrintServices(int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                return userState.getEnabledPrintServices();
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void startPrinterStateTracking(PrinterId printerId, int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public List<PrintServiceInfo> getInstalledPrintServices(int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                return userState.getInstalledPrintServices();
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.startPrinterStateTracking(printerId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public void createPrinterDiscoverySession(IPrinterDiscoveryObserver observer,
+                int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.createPrinterDiscoverySession(observer);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void stopPrinterStateTracking(PrinterId printerId, int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public void destroyPrinterDiscoverySession(IPrinterDiscoveryObserver observer,
+                int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.destroyPrinterDiscoverySession(observer);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.stopPrinterStateTracking(printerId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public void startPrinterDiscovery(IPrinterDiscoveryObserver observer,
+                List<PrinterId> priorityList, int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.startPrinterDiscovery(observer, priorityList);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void addPrintJobStateChangeListener(IPrintJobStateChangeListener listener,
-            int appId, int userId) throws RemoteException {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public void stopPrinterDiscovery(IPrinterDiscoveryObserver observer, int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.stopPrinterDiscovery(observer);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.addPrintJobStateChangeListener(listener, resolvedAppId);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public void validatePrinters(List<PrinterId> printerIds, int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.validatePrinters(printerIds);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void removePrintJobStateChangeListener(IPrintJobStateChangeListener listener,
-            int userId) {
-        final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
-        final UserState userState;
-        synchronized (mLock) {
-            userState = getOrCreateUserStateLocked(resolvedUserId);
+        @Override
+        public void startPrinterStateTracking(PrinterId printerId, int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.startPrinterStateTracking(printerId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-        final long identity = Binder.clearCallingIdentity();
-        try {
-            userState.removePrintJobStateChangeListener(listener);
-        } finally {
-            Binder.restoreCallingIdentity(identity);
+
+        @Override
+        public void stopPrinterStateTracking(PrinterId printerId, int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.stopPrinterStateTracking(printerId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
-    }
 
-    @Override
-    public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
-        if (mContext.checkCallingOrSelfPermission(Manifest.permission.DUMP)
-                != PackageManager.PERMISSION_GRANTED) {
-            pw.println("Permission Denial: can't dump PrintManager from from pid="
-                    + Binder.getCallingPid()
-                    + ", uid=" + Binder.getCallingUid());
-            return;
+        @Override
+        public void addPrintJobStateChangeListener(IPrintJobStateChangeListener listener,
+                int appId, int userId) throws RemoteException {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final int resolvedAppId = resolveCallingAppEnforcingPermissions(appId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
+            final long identity = Binder.clearCallingIdentity();
+            try {
+                userState.addPrintJobStateChangeListener(listener, resolvedAppId);
+            } finally {
+                Binder.restoreCallingIdentity(identity);
+            }
         }
 
-        synchronized (mLock) {
+        @Override
+        public void removePrintJobStateChangeListener(IPrintJobStateChangeListener listener,
+                int userId) {
+            final int resolvedUserId = resolveCallingUserEnforcingPermissions(userId);
+            final UserState userState;
+            synchronized (mLock) {
+                userState = getOrCreateUserStateLocked(resolvedUserId);
+            }
             final long identity = Binder.clearCallingIdentity();
             try {
-                pw.println("PRINT MANAGER STATE (dumpsys print)");
-                final int userStateCount = mUserStates.size();
-                for (int i = 0; i < userStateCount; i++) {
-                    UserState userState = mUserStates.valueAt(i);
-                    userState.dump(fd, pw, "");
-                    pw.println();
-                }
+                userState.removePrintJobStateChangeListener(listener);
             } finally {
                 Binder.restoreCallingIdentity(identity);
             }
         }
-    }
 
-    private void registerContentObservers() {
-        final Uri enabledPrintServicesUri = Settings.Secure.getUriFor(
-                Settings.Secure.ENABLED_PRINT_SERVICES);
+        @Override
+        public void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
+            if (mContext.checkCallingOrSelfPermission(Manifest.permission.DUMP)
+                    != PackageManager.PERMISSION_GRANTED) {
+                pw.println("Permission Denial: can't dump PrintManager from from pid="
+                        + Binder.getCallingPid()
+                        + ", uid=" + Binder.getCallingUid());
+                return;
+            }
 
-        ContentObserver observer = new ContentObserver(BackgroundThread.getHandler()) {
-            @Override
-            public void onChange(boolean selfChange, Uri uri) {
-                if (enabledPrintServicesUri.equals(uri)) {
-                    synchronized (mLock) {
-                        UserState userState = getCurrentUserStateLocked();
-                        userState.updateIfNeededLocked();
+            synchronized (mLock) {
+                final long identity = Binder.clearCallingIdentity();
+                try {
+                    pw.println("PRINT MANAGER STATE (dumpsys print)");
+                    final int userStateCount = mUserStates.size();
+                    for (int i = 0; i < userStateCount; i++) {
+                        UserState userState = mUserStates.valueAt(i);
+                        userState.dump(fd, pw, "");
+                        pw.println();
                     }
+                } finally {
+                    Binder.restoreCallingIdentity(identity);
                 }
             }
-        };
+        }
 
-        mContext.getContentResolver().registerContentObserver(enabledPrintServicesUri,
-                false, observer, UserHandle.USER_ALL);
-    }
+        private void registerContentObservers() {
+            final Uri enabledPrintServicesUri = Settings.Secure.getUriFor(
+                    Settings.Secure.ENABLED_PRINT_SERVICES);
 
-    private void registerBoradcastReceivers() {
-        PackageMonitor monitor = new PackageMonitor() {
-            @Override
-            public boolean onPackageChanged(String packageName, int uid, String[] components) {
-                synchronized (mLock) {
-                    UserState userState = getOrCreateUserStateLocked(getChangingUserId());
-                    Iterator<ComponentName> iterator = userState.getEnabledServices().iterator();
-                    while (iterator.hasNext()) {
-                        ComponentName componentName = iterator.next();
-                        if (packageName.equals(componentName.getPackageName())) {
+            ContentObserver observer = new ContentObserver(BackgroundThread.getHandler()) {
+                @Override
+                public void onChange(boolean selfChange, Uri uri) {
+                    if (enabledPrintServicesUri.equals(uri)) {
+                        synchronized (mLock) {
+                            UserState userState = getCurrentUserStateLocked();
                             userState.updateIfNeededLocked();
-                            return true;
                         }
                     }
                 }
-                return false;
-            }
-
-            @Override
-            public void onPackageRemoved(String packageName, int uid) {
-                synchronized (mLock) {
-                    UserState userState = getOrCreateUserStateLocked(getChangingUserId());
-                    Iterator<ComponentName> iterator = userState.getEnabledServices().iterator();
-                    while (iterator.hasNext()) {
-                        ComponentName componentName = iterator.next();
-                        if (packageName.equals(componentName.getPackageName())) {
-                            iterator.remove();
-                            persistComponentNamesToSettingLocked(
-                                    Settings.Secure.ENABLED_PRINT_SERVICES,
-                                    userState.getEnabledServices(), getChangingUserId());
-                            userState.updateIfNeededLocked();
-                            return;
+            };
+
+            mContext.getContentResolver().registerContentObserver(enabledPrintServicesUri,
+                    false, observer, UserHandle.USER_ALL);
+        }
+
+        private void registerBoradcastReceivers() {
+            PackageMonitor monitor = new PackageMonitor() {
+                @Override
+                public boolean onPackageChanged(String packageName, int uid, String[] components) {
+                    synchronized (mLock) {
+                        UserState userState = getOrCreateUserStateLocked(getChangingUserId());
+                        Iterator<ComponentName> iterator = userState.getEnabledServices()
+                                .iterator();
+                        while (iterator.hasNext()) {
+                            ComponentName componentName = iterator.next();
+                            if (packageName.equals(componentName.getPackageName())) {
+                                userState.updateIfNeededLocked();
+                                return true;
+                            }
                         }
                     }
+                    return false;
                 }
-            }
 
-            @Override
-            public boolean onHandleForceStop(Intent intent, String[] stoppedPackages,
-                    int uid, boolean doit) {
-                synchronized (mLock) {
-                    UserState userState = getOrCreateUserStateLocked(getChangingUserId());
-                    boolean stoppedSomePackages = false;
-                    Iterator<ComponentName> iterator = userState.getEnabledServices().iterator();
-                    while (iterator.hasNext()) {
-                        ComponentName componentName = iterator.next();
-                        String componentPackage = componentName.getPackageName();
-                        for (String stoppedPackage : stoppedPackages) {
-                            if (componentPackage.equals(stoppedPackage)) {
-                                if (!doit) {
-                                    return true;
-                                }
-                                stoppedSomePackages = true;
-                                break;
+                @Override
+                public void onPackageRemoved(String packageName, int uid) {
+                    synchronized (mLock) {
+                        UserState userState = getOrCreateUserStateLocked(getChangingUserId());
+                        Iterator<ComponentName> iterator = userState.getEnabledServices()
+                                .iterator();
+                        while (iterator.hasNext()) {
+                            ComponentName componentName = iterator.next();
+                            if (packageName.equals(componentName.getPackageName())) {
+                                iterator.remove();
+                                persistComponentNamesToSettingLocked(
+                                        Settings.Secure.ENABLED_PRINT_SERVICES,
+                                        userState.getEnabledServices(), getChangingUserId());
+                                userState.updateIfNeededLocked();
+                                return;
                             }
                         }
                     }
-                    if (stoppedSomePackages) {
-                        userState.updateIfNeededLocked();
+                }
+
+                @Override
+                public boolean onHandleForceStop(Intent intent, String[] stoppedPackages,
+                        int uid, boolean doit) {
+                    synchronized (mLock) {
+                        UserState userState = getOrCreateUserStateLocked(getChangingUserId());
+                        boolean stoppedSomePackages = false;
+                        Iterator<ComponentName> iterator = userState.getEnabledServices()
+                                .iterator();
+                        while (iterator.hasNext()) {
+                            ComponentName componentName = iterator.next();
+                            String componentPackage = componentName.getPackageName();
+                            for (String stoppedPackage : stoppedPackages) {
+                                if (componentPackage.equals(stoppedPackage)) {
+                                    if (!doit) {
+                                        return true;
+                                    }
+                                    stoppedSomePackages = true;
+                                    break;
+                                }
+                            }
+                        }
+                        if (stoppedSomePackages) {
+                            userState.updateIfNeededLocked();
+                        }
+                        return false;
                     }
-                    return false;
                 }
-            }
 
-            @Override
-            public void onPackageAdded(String packageName, int uid) {
-                Intent intent = new Intent(android.printservice.PrintService.SERVICE_INTERFACE);
-                intent.setPackage(packageName);
+                @Override
+                public void onPackageAdded(String packageName, int uid) {
+                    Intent intent = new Intent(android.printservice.PrintService.SERVICE_INTERFACE);
+                    intent.setPackage(packageName);
 
-                List<ResolveInfo> installedServices = mContext.getPackageManager()
-                        .queryIntentServicesAsUser(intent, PackageManager.GET_SERVICES,
-                                getChangingUserId());
+                    List<ResolveInfo> installedServices = mContext.getPackageManager()
+                            .queryIntentServicesAsUser(intent, PackageManager.GET_SERVICES,
+                                    getChangingUserId());
 
-                if (installedServices == null) {
-                    return;
-                }
+                    if (installedServices == null) {
+                        return;
+                    }
 
-                final int installedServiceCount = installedServices.size();
-                for (int i = 0; i < installedServiceCount; i++) {
-                    ServiceInfo serviceInfo = installedServices.get(i).serviceInfo;
-                    ComponentName component = new ComponentName(serviceInfo.packageName,
-                            serviceInfo.name);
-                    String label = serviceInfo.loadLabel(mContext.getPackageManager()).toString();
-                    showEnableInstalledPrintServiceNotification(component, label,
-                            getChangingUserId());
+                    final int installedServiceCount = installedServices.size();
+                    for (int i = 0; i < installedServiceCount; i++) {
+                        ServiceInfo serviceInfo = installedServices.get(i).serviceInfo;
+                        ComponentName component = new ComponentName(serviceInfo.packageName,
+                                serviceInfo.name);
+                        String label = serviceInfo.loadLabel(mContext.getPackageManager())
+                                .toString();
+                        showEnableInstalledPrintServiceNotification(component, label,
+                                getChangingUserId());
+                    }
                 }
-            }
 
-            private void persistComponentNamesToSettingLocked(String settingName,
-                    Set<ComponentName> componentNames, int userId) {
-                StringBuilder builder = new StringBuilder();
-                for (ComponentName componentName : componentNames) {
-                    if (builder.length() > 0) {
-                        builder.append(COMPONENT_NAME_SEPARATOR);
+                private void persistComponentNamesToSettingLocked(String settingName,
+                        Set<ComponentName> componentNames, int userId) {
+                    StringBuilder builder = new StringBuilder();
+                    for (ComponentName componentName : componentNames) {
+                        if (builder.length() > 0) {
+                            builder.append(COMPONENT_NAME_SEPARATOR);
+                        }
+                        builder.append(componentName.flattenToShortString());
                     }
-                    builder.append(componentName.flattenToShortString());
+                    Settings.Secure.putStringForUser(mContext.getContentResolver(),
+                            settingName, builder.toString(), userId);
                 }
-                Settings.Secure.putStringForUser(mContext.getContentResolver(),
-                        settingName, builder.toString(), userId);
-            }
-        };
-
-        // package changes
-        monitor.register(mContext, BackgroundThread.getHandler().getLooper(),
-                UserHandle.ALL, true);
-
-        // user changes
-        IntentFilter intentFilter = new IntentFilter();
-        intentFilter.addAction(Intent.ACTION_USER_SWITCHED);
-        intentFilter.addAction(Intent.ACTION_USER_REMOVED);
-
-        mContext.registerReceiverAsUser(new BroadcastReceiver() {
-            @Override
-            public void onReceive(Context context, Intent intent) {
-                String action = intent.getAction();
-                if (Intent.ACTION_USER_SWITCHED.equals(action)) {
-                    switchUser(intent.getIntExtra(Intent.EXTRA_USER_HANDLE, 0));
-                } else if (Intent.ACTION_USER_REMOVED.equals(action)) {
-                    removeUser(intent.getIntExtra(Intent.EXTRA_USER_HANDLE, 0));
+            };
+
+            // package changes
+            monitor.register(mContext, BackgroundThread.getHandler().getLooper(),
+                    UserHandle.ALL, true);
+
+            // user changes
+            IntentFilter intentFilter = new IntentFilter();
+            intentFilter.addAction(Intent.ACTION_USER_SWITCHED);
+            intentFilter.addAction(Intent.ACTION_USER_REMOVED);
+
+            mContext.registerReceiverAsUser(new BroadcastReceiver() {
+                @Override
+                public void onReceive(Context context, Intent intent) {
+                    String action = intent.getAction();
+                    if (Intent.ACTION_USER_SWITCHED.equals(action)) {
+                        switchUser(intent.getIntExtra(Intent.EXTRA_USER_HANDLE, 0));
+                    } else if (Intent.ACTION_USER_REMOVED.equals(action)) {
+                        removeUser(intent.getIntExtra(Intent.EXTRA_USER_HANDLE, 0));
+                    }
                 }
-            }
-        }, UserHandle.ALL, intentFilter, null, BackgroundThread.getHandler());
-    }
-
-    private UserState getCurrentUserStateLocked() {
-        return getOrCreateUserStateLocked(mCurrentUserId);
-    }
+            }, UserHandle.ALL, intentFilter, null, BackgroundThread.getHandler());
+        }
 
-    private UserState getOrCreateUserStateLocked(int userId) {
-        UserState userState = mUserStates.get(userId);
-        if (userState == null) {
-            userState = new UserState(mContext, userId, mLock);
-            mUserStates.put(userId, userState);
+        private UserState getCurrentUserStateLocked() {
+            return getOrCreateUserStateLocked(mCurrentUserId);
         }
-        return userState;
-    }
 
-    private void switchUser(int newUserId) {
-        UserState userState;
-        synchronized (mLock) {
-            if (newUserId == mCurrentUserId) {
-                return;
-            }
-            mCurrentUserId = newUserId;
-            userState = mUserStates.get(mCurrentUserId);
+        private UserState getOrCreateUserStateLocked(int userId) {
+            UserState userState = mUserStates.get(userId);
             if (userState == null) {
-                userState = getCurrentUserStateLocked();
-                userState.updateIfNeededLocked();
-            } else {
-                userState.updateIfNeededLocked();
+                userState = new UserState(mContext, userId, mLock);
+                mUserStates.put(userId, userState);
             }
+            return userState;
         }
-        // This is the first time we switch to this user after boot, so
-        // now is the time to remove obsolete print jobs since they
-        // are from the last boot and no application would query them.
-        userState.removeObsoletePrintJobs();
-    }
 
-    private void removeUser(int removedUserId) {
-        synchronized (mLock) {
-            UserState userState = mUserStates.get(removedUserId);
-            if (userState != null) {
-                userState.destroyLocked();
-                mUserStates.remove(removedUserId);
+        private void switchUser(int newUserId) {
+            UserState userState;
+            synchronized (mLock) {
+                if (newUserId == mCurrentUserId) {
+                    return;
+                }
+                mCurrentUserId = newUserId;
+                userState = mUserStates.get(mCurrentUserId);
+                if (userState == null) {
+                    userState = getCurrentUserStateLocked();
+                    userState.updateIfNeededLocked();
+                } else {
+                    userState.updateIfNeededLocked();
+                }
+            }
+            // This is the first time we switch to this user after boot, so
+            // now is the time to remove obsolete print jobs since they
+            // are from the last boot and no application would query them.
+            userState.removeObsoletePrintJobs();
+        }
+
+        private void removeUser(int removedUserId) {
+            synchronized (mLock) {
+                UserState userState = mUserStates.get(removedUserId);
+                if (userState != null) {
+                    userState.destroyLocked();
+                    mUserStates.remove(removedUserId);
+                }
             }
         }
-    }
 
-    private int resolveCallingAppEnforcingPermissions(int appId) {
-        final int callingUid = Binder.getCallingUid();
-        if (callingUid == 0 || callingUid == Process.SYSTEM_UID
-                || callingUid == Process.SHELL_UID) {
-            return appId;
-        }
-        final int callingAppId = UserHandle.getAppId(callingUid);
-        if (appId == callingAppId) {
+        private int resolveCallingAppEnforcingPermissions(int appId) {
+            final int callingUid = Binder.getCallingUid();
+            if (callingUid == 0 || callingUid == Process.SYSTEM_UID
+                    || callingUid == Process.SHELL_UID) {
+                return appId;
+            }
+            final int callingAppId = UserHandle.getAppId(callingUid);
+            if (appId == callingAppId) {
+                return appId;
+            }
+            if (mContext.checkCallingPermission(
+                    "com.android.printspooler.permission.ACCESS_ALL_PRINT_JOBS")
+                    != PackageManager.PERMISSION_GRANTED) {
+                throw new SecurityException("Call from app " + callingAppId + " as app "
+                        + appId + " without com.android.printspooler.permission"
+                        + ".ACCESS_ALL_PRINT_JOBS");
+            }
             return appId;
         }
-        if (mContext.checkCallingPermission(
-                "com.android.printspooler.permission.ACCESS_ALL_PRINT_JOBS")
-                != PackageManager.PERMISSION_GRANTED) {
-            throw new SecurityException("Call from app " + callingAppId + " as app "
-                    + appId + " without com.android.printspooler.permission"
-                    + ".ACCESS_ALL_PRINT_JOBS");
-        }
-        return appId;
-    }
 
-    private int resolveCallingUserEnforcingPermissions(int userId) {
-        final int callingUid = Binder.getCallingUid();
-        if (callingUid == 0 || callingUid == Process.SYSTEM_UID
-                || callingUid == Process.SHELL_UID) {
-            return userId;
-        }
-        final int callingUserId = UserHandle.getUserId(callingUid);
-        if (callingUserId == userId) {
-            return userId;
-        }
-        if (mContext.checkCallingPermission(Manifest.permission.INTERACT_ACROSS_USERS_FULL)
-                != PackageManager.PERMISSION_GRANTED
-            ||  mContext.checkCallingPermission(Manifest.permission.INTERACT_ACROSS_USERS)
-                != PackageManager.PERMISSION_GRANTED) {
-            if (userId == UserHandle.USER_CURRENT_OR_SELF) {
-                return callingUserId;
-            }
-            throw new SecurityException("Call from user " + callingUserId + " as user "
-                + userId + " without permission INTERACT_ACROSS_USERS or "
-                + "INTERACT_ACROSS_USERS_FULL not allowed.");
-        }
-        if (userId == UserHandle.USER_CURRENT || userId == UserHandle.USER_CURRENT_OR_SELF) {
-            return mCurrentUserId;
+        private int resolveCallingUserEnforcingPermissions(int userId) {
+            final int callingUid = Binder.getCallingUid();
+            if (callingUid == 0 || callingUid == Process.SYSTEM_UID
+                    || callingUid == Process.SHELL_UID) {
+                return userId;
+            }
+            final int callingUserId = UserHandle.getUserId(callingUid);
+            if (callingUserId == userId) {
+                return userId;
+            }
+            if (mContext.checkCallingPermission(Manifest.permission.INTERACT_ACROSS_USERS_FULL)
+                    != PackageManager.PERMISSION_GRANTED
+                ||  mContext.checkCallingPermission(Manifest.permission.INTERACT_ACROSS_USERS)
+                    != PackageManager.PERMISSION_GRANTED) {
+                if (userId == UserHandle.USER_CURRENT_OR_SELF) {
+                    return callingUserId;
+                }
+                throw new SecurityException("Call from user " + callingUserId + " as user "
+                    + userId + " without permission INTERACT_ACROSS_USERS or "
+                    + "INTERACT_ACROSS_USERS_FULL not allowed.");
+            }
+            if (userId == UserHandle.USER_CURRENT || userId == UserHandle.USER_CURRENT_OR_SELF) {
+                return mCurrentUserId;
+            }
+            throw new IllegalArgumentException("Calling user can be changed to only "
+                    + "UserHandle.USER_CURRENT or UserHandle.USER_CURRENT_OR_SELF.");
         }
-        throw new IllegalArgumentException("Calling user can be changed to only "
-                + "UserHandle.USER_CURRENT or UserHandle.USER_CURRENT_OR_SELF.");
-    }
 
-    private String resolveCallingPackageNameEnforcingSecurity(String packageName) {
-        if (TextUtils.isEmpty(packageName)) {
-            return null;
-        }
-        String[] packages = mContext.getPackageManager().getPackagesForUid(
-                Binder.getCallingUid());
-        final int packageCount = packages.length;
-        for (int i = 0; i < packageCount; i++) {
-            if (packageName.equals(packages[i])) {
-                return packageName;
+        private String resolveCallingPackageNameEnforcingSecurity(String packageName) {
+            if (TextUtils.isEmpty(packageName)) {
+                return null;
+            }
+            String[] packages = mContext.getPackageManager().getPackagesForUid(
+                    Binder.getCallingUid());
+            final int packageCount = packages.length;
+            for (int i = 0; i < packageCount; i++) {
+                if (packageName.equals(packages[i])) {
+                    return packageName;
+                }
             }
+            return null;
         }
-        return null;
-    }
 
-    private void showEnableInstalledPrintServiceNotification(ComponentName component,
-            String label, int userId) {
-        UserHandle userHandle = new UserHandle(userId);
+        private void showEnableInstalledPrintServiceNotification(ComponentName component,
+                String label, int userId) {
+            UserHandle userHandle = new UserHandle(userId);
 
-        Intent intent = new Intent(Settings.ACTION_PRINT_SETTINGS);
-        intent.putExtra(EXTRA_PRINT_SERVICE_COMPONENT_NAME, component.flattenToString());
+            Intent intent = new Intent(Settings.ACTION_PRINT_SETTINGS);
+            intent.putExtra(EXTRA_PRINT_SERVICE_COMPONENT_NAME, component.flattenToString());
 
-        PendingIntent pendingIntent = PendingIntent.getActivityAsUser(mContext, 0, intent,
-                PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_CANCEL_CURRENT, null, userHandle);
+            PendingIntent pendingIntent = PendingIntent.getActivityAsUser(mContext, 0, intent,
+                    PendingIntent.FLAG_ONE_SHOT | PendingIntent.FLAG_CANCEL_CURRENT, null,
+                    userHandle);
 
-        Notification.Builder builder = new Notification.Builder(mContext)
-                .setSmallIcon(R.drawable.ic_print)
-                .setContentTitle(mContext.getString(R.string.print_service_installed_title, label))
-                .setContentText(mContext.getString(R.string.print_service_installed_message))
-                .setContentIntent(pendingIntent)
-                .setWhen(System.currentTimeMillis())
-                .setAutoCancel(true)
-                .setShowWhen(true);
+            Notification.Builder builder = new Notification.Builder(mContext)
+                    .setSmallIcon(R.drawable.ic_print)
+                    .setContentTitle(mContext.getString(R.string.print_service_installed_title,
+                            label))
+                    .setContentText(mContext.getString(R.string.print_service_installed_message))
+                    .setContentIntent(pendingIntent)
+                    .setWhen(System.currentTimeMillis())
+                    .setAutoCancel(true)
+                    .setShowWhen(true);
 
-        NotificationManager notificationManager = (NotificationManager) mContext
-                .getSystemService(Context.NOTIFICATION_SERVICE);
+            NotificationManager notificationManager = (NotificationManager) mContext
+                    .getSystemService(Context.NOTIFICATION_SERVICE);
 
-        String notificationTag = getClass().getName() + ":" + component.flattenToString();
-        notificationManager.notifyAsUser(notificationTag, 0, builder.build(),
-                userHandle);
+            String notificationTag = getClass().getName() + ":" + component.flattenToString();
+            notificationManager.notifyAsUser(notificationTag, 0, builder.build(),
+                    userHandle);
+        }
     }
 }