Add firebase auth destroy check before tenant operations. (#386)

This addresses some TODOs left as part of the initiative to add multi-tenancy support (see issue #332).

Author: micahstairs

src/main/java/com/google/firebase/auth/AbstractFirebaseAuth.java

@@ -1095,9 +1095,13 @@ private void checkNotDestroyed() {
     }
   }
 
-  void destroy() {
+  final void destroy() {
     synchronized (lock) {
+      doDestroy();
       destroyed.set(true);
     }
   }
+
+  /** Performs any additional required clean up. */
+  protected abstract void doDestroy();
 }

src/main/java/com/google/firebase/auth/FirebaseAuth.java

@@ -23,6 +23,7 @@
 import com.google.firebase.ImplFirebaseTrampolines;
 import com.google.firebase.auth.internal.FirebaseTokenFactory;
 import com.google.firebase.internal.FirebaseService;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * This class is the entry point for all server-side Firebase Authentication actions.
@@ -37,6 +38,7 @@ public class FirebaseAuth extends AbstractFirebaseAuth {
   private static final String SERVICE_ID = FirebaseAuth.class.getName();
 
   private final Supplier<TenantManager> tenantManager;
+  private final AtomicBoolean tenantManagerCreated = new AtomicBoolean(false);
 
   private FirebaseAuth(final Builder builder) {
     super(
@@ -47,6 +49,7 @@ private FirebaseAuth(final Builder builder) {
     tenantManager = threadSafeMemoize(new Supplier<TenantManager>() {
       @Override
       public TenantManager get() {
+        tenantManagerCreated.set(true);
         return new TenantManager(builder.firebaseApp, getUserManager());
       }
     });
@@ -80,6 +83,14 @@ public static synchronized FirebaseAuth getInstance(FirebaseApp app) {
     return service.getInstance();
   }
 
+  @Override
+  protected void doDestroy() {
+    // Only destroy the tenant manager if it has been created.
+    if (tenantManagerCreated.get()) {
+      getTenantManager().destroy();
+    }
+  }
+
   private static FirebaseAuth fromApp(final FirebaseApp app) {
     return FirebaseAuth.builder()
         .setFirebaseApp(app)

src/main/java/com/google/firebase/auth/TenantManager.java

@@ -18,6 +18,7 @@
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
+import static com.google.common.base.Preconditions.checkState;
 
 import com.google.api.client.json.JsonFactory;
 import com.google.api.core.ApiFuture;
@@ -31,6 +32,7 @@
 import com.google.firebase.internal.CallableOperation;
 import com.google.firebase.internal.NonNull;
 import com.google.firebase.internal.Nullable;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 /**
  * This class can be used to perform a variety of tenant-related operations, including creating,
@@ -40,6 +42,9 @@
  */
 public final class TenantManager {
 
+  private final Object lock = new Object();
+  private final AtomicBoolean destroyed = new AtomicBoolean(false);
+
   private final FirebaseApp firebaseApp;
   private final FirebaseUserManager userManager;
 
@@ -74,7 +79,7 @@ public ApiFuture<Tenant> getTenantAsync(@NonNull String tenantId) {
   }
 
   private CallableOperation<Tenant, FirebaseAuthException> getTenantOp(final String tenantId) {
-    // TODO(micahstairs): Add a check to make sure the app has not been destroyed yet.
+    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(tenantId), "tenantId must not be null or empty");
     return new CallableOperation<Tenant, FirebaseAuthException>() {
       @Override
@@ -142,7 +147,7 @@ public ApiFuture<ListTenantsPage> listTenantsAsync(@Nullable String pageToken, i
 
   private CallableOperation<ListTenantsPage, FirebaseAuthException> listTenantsOp(
       @Nullable final String pageToken, final int maxResults) {
-    // TODO(micahstairs): Add a check to make sure the app has not been destroyed yet.
+    checkNotDestroyed();
     final TenantSource tenantSource = new DefaultTenantSource(userManager);
     final PageFactory factory = new PageFactory(tenantSource, maxResults, pageToken);
     return new CallableOperation<ListTenantsPage, FirebaseAuthException>() {
@@ -180,7 +185,7 @@ public ApiFuture<Tenant> createTenantAsync(@NonNull CreateRequest request) {
 
   private CallableOperation<Tenant, FirebaseAuthException> createTenantOp(
       final CreateRequest request) {
-    // TODO(micahstairs): Add a check to make sure the app has not been destroyed yet.
+    checkNotDestroyed();
     checkNotNull(request, "create request must not be null");
     return new CallableOperation<Tenant, FirebaseAuthException>() {
       @Override
@@ -218,7 +223,7 @@ public ApiFuture<Tenant> updateTenantAsync(@NonNull UpdateRequest request) {
 
   private CallableOperation<Tenant, FirebaseAuthException> updateTenantOp(
       final UpdateRequest request) {
-    // TODO(micahstairs): Add a check to make sure the app has not been destroyed yet.
+    checkNotDestroyed();
     checkNotNull(request, "update request must not be null");
     return new CallableOperation<Tenant, FirebaseAuthException>() {
       @Override
@@ -253,7 +258,7 @@ public ApiFuture<Void> deleteTenantAsync(String tenantId) {
   }
 
   private CallableOperation<Void, FirebaseAuthException> deleteTenantOp(final String tenantId) {
-    // TODO(micahstairs): Add a check to make sure the app has not been destroyed yet.
+    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(tenantId), "tenantId must not be null or empty");
     return new CallableOperation<Void, FirebaseAuthException>() {
       @Override
@@ -263,4 +268,17 @@ protected Void execute() throws FirebaseAuthException {
       }
     };
   }
+
+  void checkNotDestroyed() {
+    synchronized (lock) {
+      checkState(
+          !destroyed.get(),
+          "TenantManager instance is no longer alive. This happens when "
+              + "the parent FirebaseApp instance has been deleted.");
+    }
+  }
+
+  protected void destroy() {
+    destroyed.set(true);
+  }
 }