fix: Cleaning up FirebaseApp state management (#476)

Author: hiranya911

src/main/java/com/google/firebase/FirebaseApp.java

@@ -277,6 +277,8 @@ public FirebaseOptions getOptions() {
    */
   @Nullable
   String getProjectId() {
+    checkNotDeleted();
+
     // Try to get project ID from user-specified options.
     String projectId = options.getProjectId();
 
@@ -314,8 +316,10 @@ public String toString() {
   }
 
   /**
-   * Deletes the {@link FirebaseApp} and all its data. All calls to this {@link FirebaseApp}
-   * instance will throw once it has been called.
+   * Deletes this {@link FirebaseApp} object, and releases any local state and managed resources
+   * associated with it. All calls to this {@link FirebaseApp} instance will throw once this method
+   * has been called. This also releases any managed resources allocated by other services
+   * attached to this object instance (e.g. {@code FirebaseAuth}).
    *
    * <p>A no-op if delete was called before.
    */

src/main/java/com/google/firebase/ImplFirebaseTrampolines.java

@@ -26,7 +26,6 @@
 import com.google.firebase.internal.NonNull;
 
 import java.util.concurrent.Callable;
-import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledFuture;
 import java.util.concurrent.ThreadFactory;
 

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

@@ -18,7 +18,6 @@
 
 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.client.util.Clock;
@@ -164,7 +163,6 @@ public ApiFuture<String> createCustomTokenAsync(
 
   private CallableOperation<String, FirebaseAuthException> createCustomTokenOp(
       final String uid, final Map<String, Object> developerClaims) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(uid), "uid must not be null or empty");
     final FirebaseTokenFactory tokenFactory = this.tokenFactory.get();
     return new CallableOperation<String, FirebaseAuthException>() {
@@ -208,7 +206,6 @@ public ApiFuture<String> createSessionCookieAsync(
 
   private CallableOperation<String, FirebaseAuthException> createSessionCookieOp(
       final String idToken, final SessionCookieOptions options) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(idToken), "idToken must not be null or empty");
     checkNotNull(options, "options must not be null");
     final FirebaseUserManager userManager = getUserManager();
@@ -299,7 +296,6 @@ public ApiFuture<FirebaseToken> verifyIdTokenAsync(@NonNull String idToken) {
 
   private CallableOperation<FirebaseToken, FirebaseAuthException> verifyIdTokenOp(
       final String idToken, final boolean checkRevoked) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(idToken), "ID token must not be null or empty");
     final FirebaseTokenVerifier verifier = getIdTokenVerifier(checkRevoked);
     return new CallableOperation<FirebaseToken, FirebaseAuthException>() {
@@ -380,7 +376,6 @@ public ApiFuture<FirebaseToken> verifySessionCookieAsync(String cookie, boolean
 
   private CallableOperation<FirebaseToken, FirebaseAuthException> verifySessionCookieOp(
       final String cookie, final boolean checkRevoked) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(cookie), "Session cookie must not be null or empty");
     final FirebaseTokenVerifier sessionCookieVerifier = getSessionCookieVerifier(checkRevoked);
     return new CallableOperation<FirebaseToken, FirebaseAuthException>() {
@@ -434,7 +429,6 @@ public ApiFuture<Void> revokeRefreshTokensAsync(@NonNull String uid) {
   }
 
   private CallableOperation<Void, FirebaseAuthException> revokeRefreshTokensOp(final String uid) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(uid), "uid must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<Void, FirebaseAuthException>() {
@@ -475,7 +469,6 @@ public ApiFuture<UserRecord> getUserAsync(@NonNull String uid) {
   }
 
   private CallableOperation<UserRecord, FirebaseAuthException> getUserOp(final String uid) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(uid), "uid must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserRecord, FirebaseAuthException>() {
@@ -513,7 +506,6 @@ public ApiFuture<UserRecord> getUserByEmailAsync(@NonNull String email) {
 
   private CallableOperation<UserRecord, FirebaseAuthException> getUserByEmailOp(
       final String email) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(email), "email must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserRecord, FirebaseAuthException>() {
@@ -551,7 +543,6 @@ public ApiFuture<UserRecord> getUserByPhoneNumberAsync(@NonNull String phoneNumb
 
   private CallableOperation<UserRecord, FirebaseAuthException> getUserByPhoneNumberOp(
       final String phoneNumber) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(phoneNumber), "phone number must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserRecord, FirebaseAuthException>() {
@@ -620,7 +611,6 @@ public ApiFuture<ListUsersPage> listUsersAsync(@Nullable String pageToken, int m
 
   private CallableOperation<ListUsersPage, FirebaseAuthException> listUsersOp(
       @Nullable final String pageToken, final int maxResults) {
-    checkNotDestroyed();
     final FirebaseUserManager userManager = getUserManager();
     final DefaultUserSource source = new DefaultUserSource(userManager, jsonFactory);
     final ListUsersPage.Factory factory = new ListUsersPage.Factory(source, maxResults, pageToken);
@@ -661,7 +651,6 @@ public ApiFuture<UserRecord> createUserAsync(@NonNull UserRecord.CreateRequest r
 
   private CallableOperation<UserRecord, FirebaseAuthException> createUserOp(
       final UserRecord.CreateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "create request must not be null");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserRecord, FirebaseAuthException>() {
@@ -701,7 +690,6 @@ public ApiFuture<UserRecord> updateUserAsync(@NonNull UserRecord.UpdateRequest r
 
   private CallableOperation<UserRecord, FirebaseAuthException> updateUserOp(
       final UserRecord.UpdateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "update request must not be null");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserRecord, FirebaseAuthException>() {
@@ -754,7 +742,6 @@ public ApiFuture<Void> setCustomUserClaimsAsync(
 
   private CallableOperation<Void, FirebaseAuthException> setCustomUserClaimsOp(
       final String uid, final Map<String, Object> claims) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(uid), "uid must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<Void, FirebaseAuthException>() {
@@ -793,7 +780,6 @@ public ApiFuture<Void> deleteUserAsync(String uid) {
   }
 
   private CallableOperation<Void, FirebaseAuthException> deleteUserOp(final String uid) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(uid), "uid must not be null or empty");
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<Void, FirebaseAuthException>() {
@@ -876,7 +862,6 @@ public ApiFuture<UserImportResult> importUsersAsync(
 
   private CallableOperation<UserImportResult, FirebaseAuthException> importUsersOp(
       final List<ImportUserRecord> users, final UserImportOptions options) {
-    checkNotDestroyed();
     final UserImportRequest request = new UserImportRequest(users, options, jsonFactory);
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<UserImportResult, FirebaseAuthException>() {
@@ -931,7 +916,6 @@ public ApiFuture<GetUsersResult> getUsersAsync(@NonNull Collection<UserIdentifie
 
   private CallableOperation<GetUsersResult, FirebaseAuthException> getUsersOp(
       @NonNull final Collection<UserIdentifier> identifiers) {
-    checkNotDestroyed();
     checkNotNull(identifiers, "identifiers must not be null");
     checkArgument(identifiers.size() <= FirebaseUserManager.MAX_GET_ACCOUNTS_BATCH_SIZE,
         "identifiers parameter must have <= " + FirebaseUserManager.MAX_GET_ACCOUNTS_BATCH_SIZE
@@ -1004,7 +988,6 @@ public ApiFuture<DeleteUsersResult> deleteUsersAsync(List<String> uids) {
 
   private CallableOperation<DeleteUsersResult, FirebaseAuthException> deleteUsersOp(
       final List<String> uids) {
-    checkNotDestroyed();
     checkNotNull(uids, "uids must not be null");
     for (String uid : uids) {
       UserRecord.checkUid(uid);
@@ -1178,7 +1161,6 @@ public ApiFuture<String> generateSignInWithEmailLinkAsync(
 
   private CallableOperation<String, FirebaseAuthException> generateEmailActionLinkOp(
       final EmailLinkType type, final String email, final ActionCodeSettings settings) {
-    checkNotDestroyed();
     checkArgument(!Strings.isNullOrEmpty(email), "email must not be null or empty");
     if (type == EmailLinkType.EMAIL_SIGNIN) {
       checkNotNull(settings, "ActionCodeSettings must not be null when generating sign-in links");
@@ -1227,7 +1209,6 @@ public ApiFuture<OidcProviderConfig> createOidcProviderConfigAsync(
 
   private CallableOperation<OidcProviderConfig, FirebaseAuthException>
       createOidcProviderConfigOp(final OidcProviderConfig.CreateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "Create request must not be null.");
     OidcProviderConfig.checkOidcProviderId(request.getProviderId());
     final FirebaseUserManager userManager = getUserManager();
@@ -1271,7 +1252,6 @@ public ApiFuture<OidcProviderConfig> updateOidcProviderConfigAsync(
 
   private CallableOperation<OidcProviderConfig, FirebaseAuthException> updateOidcProviderConfigOp(
       final OidcProviderConfig.UpdateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "Update request must not be null.");
     checkArgument(!request.getProperties().isEmpty(),
         "Update request must have at least one property set.");
@@ -1316,7 +1296,6 @@ public ApiFuture<OidcProviderConfig> getOidcProviderConfigAsync(@NonNull String
 
   private CallableOperation<OidcProviderConfig, FirebaseAuthException>
       getOidcProviderConfigOp(final String providerId) {
-    checkNotDestroyed();
     OidcProviderConfig.checkOidcProviderId(providerId);
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<OidcProviderConfig, FirebaseAuthException>() {
@@ -1400,7 +1379,6 @@ public ApiFuture<ListProviderConfigsPage<OidcProviderConfig>> listOidcProviderCo
 
   private CallableOperation<ListProviderConfigsPage<OidcProviderConfig>, FirebaseAuthException>
       listOidcProviderConfigsOp(@Nullable final String pageToken, final int maxResults) {
-    checkNotDestroyed();
     final FirebaseUserManager userManager = getUserManager();
     final DefaultOidcProviderConfigSource source = new DefaultOidcProviderConfigSource(userManager);
     final ListProviderConfigsPage.Factory<OidcProviderConfig> factory =
@@ -1443,7 +1421,6 @@ public ApiFuture<Void> deleteOidcProviderConfigAsync(String providerId) {
 
   private CallableOperation<Void, FirebaseAuthException> deleteOidcProviderConfigOp(
       final String providerId) {
-    checkNotDestroyed();
     OidcProviderConfig.checkOidcProviderId(providerId);
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<Void, FirebaseAuthException>() {
@@ -1490,7 +1467,6 @@ public ApiFuture<SamlProviderConfig> createSamlProviderConfigAsync(
 
   private CallableOperation<SamlProviderConfig, FirebaseAuthException>
       createSamlProviderConfigOp(final SamlProviderConfig.CreateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "Create request must not be null.");
     SamlProviderConfig.checkSamlProviderId(request.getProviderId());
     final FirebaseUserManager userManager = getUserManager();
@@ -1534,7 +1510,6 @@ public ApiFuture<SamlProviderConfig> updateSamlProviderConfigAsync(
 
   private CallableOperation<SamlProviderConfig, FirebaseAuthException> updateSamlProviderConfigOp(
       final SamlProviderConfig.UpdateRequest request) {
-    checkNotDestroyed();
     checkNotNull(request, "Update request must not be null.");
     checkArgument(!request.getProperties().isEmpty(),
         "Update request must have at least one property set.");
@@ -1579,7 +1554,6 @@ public ApiFuture<SamlProviderConfig> getSamlProviderConfigAsync(@NonNull String
 
   private CallableOperation<SamlProviderConfig, FirebaseAuthException>
       getSamlProviderConfigOp(final String providerId) {
-    checkNotDestroyed();
     SamlProviderConfig.checkSamlProviderId(providerId);
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<SamlProviderConfig, FirebaseAuthException>() {
@@ -1663,7 +1637,6 @@ public ApiFuture<ListProviderConfigsPage<SamlProviderConfig>> listSamlProviderCo
 
   private CallableOperation<ListProviderConfigsPage<SamlProviderConfig>, FirebaseAuthException>
       listSamlProviderConfigsOp(@Nullable final String pageToken, final int maxResults) {
-    checkNotDestroyed();
     final FirebaseUserManager userManager = getUserManager();
     final DefaultSamlProviderConfigSource source = new DefaultSamlProviderConfigSource(userManager);
     final ListProviderConfigsPage.Factory<SamlProviderConfig> factory =
@@ -1706,7 +1679,6 @@ public ApiFuture<Void> deleteSamlProviderConfigAsync(String providerId) {
 
   private CallableOperation<Void, FirebaseAuthException> deleteSamlProviderConfigOp(
       final String providerId) {
-    checkNotDestroyed();
     SamlProviderConfig.checkSamlProviderId(providerId);
     final FirebaseUserManager userManager = getUserManager();
     return new CallableOperation<Void, FirebaseAuthException>() {
@@ -1729,32 +1701,12 @@ <T> Supplier<T> threadSafeMemoize(final Supplier<T> supplier) {
           public T get() {
             checkNotNull(supplier);
             synchronized (lock) {
-              checkNotDestroyed();
               return supplier.get();
             }
           }
         });
   }
 
-  private void checkNotDestroyed() {
-    synchronized (lock) {
-      checkState(
-          !destroyed.get(),
-          "FirebaseAuth instance is no longer alive. This happens when "
-              + "the parent FirebaseApp instance has been deleted.");
-    }
-  }
-
-  final void destroy() {
-    synchronized (lock) {
-      doDestroy();
-      destroyed.set(true);
-    }
-  }
-
-  /** Performs any additional required clean up. */
-  protected abstract void doDestroy();
-
   protected abstract static class Builder<T extends  Builder<T>> {
 
     private FirebaseApp firebaseApp;

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

@@ -69,9 +69,6 @@ public static synchronized FirebaseAuth getInstance(FirebaseApp app) {
     return service.getInstance();
   }
 
-  @Override
-  protected void doDestroy() { }
-
   private static FirebaseAuth fromApp(final FirebaseApp app) {
     return populateBuilderFromApp(builder(), app, null)
         .setTenantManager(new Supplier<TenantManager>() {
@@ -88,11 +85,6 @@ private static class FirebaseAuthService extends FirebaseService<FirebaseAuth> {
     FirebaseAuthService(FirebaseApp app) {
       super(SERVICE_ID, FirebaseAuth.fromApp(app));
     }
-
-    @Override
-    public void destroy() {
-      instance.destroy();
-    }
   }
 
   static Builder builder() {

src/main/java/com/google/firebase/auth/multitenancy/TenantAwareFirebaseAuth.java

@@ -69,11 +69,6 @@ public ApiFuture<String> apply(FirebaseToken input) {
     }, MoreExecutors.directExecutor());
   }
 
-  @Override
-  protected void doDestroy() {
-    // Nothing extra needs to be destroyed.
-  }
-
   static TenantAwareFirebaseAuth fromApp(FirebaseApp app, String tenantId) {
     return populateBuilderFromApp(builder(), app, tenantId)
         .setTenantId(tenantId)

src/main/java/com/google/firebase/cloud/StorageClient.java

@@ -106,13 +106,5 @@ private static class StorageClientService extends FirebaseService<StorageClient>
     StorageClientService(StorageClient client) {
       super(SERVICE_ID, client);
     }
-
-    @Override
-    public void destroy() {
-      // NOTE: We don't explicitly tear down anything here, but public methods of StorageClient
-      // will now fail because calls to getOptions() and getToken() will hit FirebaseApp,
-      // which will throw once the app is deleted.
-    }
   }
-
 }

src/main/java/com/google/firebase/database/FirebaseDatabase.java

@@ -173,7 +173,7 @@ static FirebaseDatabase createForTests(
     return db;
   }
 
-  /** 
+  /**
    * @return The version for this build of the Firebase Database client
    */
   public static String getSdkVersion() {
@@ -358,6 +358,10 @@ DatabaseConfig getConfig() {
     return this.config;
   }
 
+  /**
+   * Tears down the WebSocket connections and background threads started by this {@code
+   * FirebaseDatabase} instance thus disconnecting from the remote database.
+   */
   void destroy() {
     synchronized (lock) {
       if (destroyed.get()) {

src/main/java/com/google/firebase/iid/FirebaseInstanceId.java

@@ -200,12 +200,5 @@ private static class FirebaseInstanceIdService extends FirebaseService<FirebaseI
     FirebaseInstanceIdService(FirebaseApp app) {
       super(SERVICE_ID, new FirebaseInstanceId(app));
     }
-
-    @Override
-    public void destroy() {
-      // NOTE: We don't explicitly tear down anything here, but public methods of StorageClient
-      // will now fail because calls to getOptions() and getToken() will hit FirebaseApp,
-      // which will throw once the app is deleted.
-    }
   }
 }

src/main/java/com/google/firebase/internal/FirebaseService.java

@@ -28,7 +28,7 @@
  *
  * @param <T> Type of the service
  */
-public abstract class FirebaseService<T> {
+public class FirebaseService<T> {
 
   private final String id;
   protected final T instance;
@@ -62,5 +62,7 @@ public final T getInstance() {
    * Tear down this FirebaseService instance and the service object wrapped in it, cleaning up
    * any allocated resources in the process.
    */
-  public abstract void destroy();
+  public void destroy() {
+    // Child classes can override this method to implement any service-specific cleanup logic.
+  }
 }

src/main/java/com/google/firebase/messaging/FirebaseMessaging.java

@@ -403,13 +403,6 @@ private static class FirebaseMessagingService extends FirebaseService<FirebaseMe
     FirebaseMessagingService(FirebaseApp app) {
       super(SERVICE_ID, FirebaseMessaging.fromApp(app));
     }
-
-    @Override
-    public void destroy() {
-      // NOTE: We don't explicitly tear down anything here, but public methods of FirebaseMessaging
-      // will now fail because calls to getOptions() and getToken() will hit FirebaseApp,
-      // which will throw once the app is deleted.
-    }
   }
 
   private static FirebaseMessaging fromApp(final FirebaseApp app) {