cleanup, NonNull annotation, never return null in PgpDecryptVerify

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/BaseOperation.java

@@ -19,6 +19,7 @@ package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
 import android.os.Parcelable;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
 import org.sufficientlysecure.keychain.pgp.PassphraseCacheInterface;
@@ -76,9 +77,8 @@ public abstract class BaseOperation <T extends Parcelable> implements Passphrase
         mCancelled = cancelled;
     }
 
-    public OperationResult execute(T input, CryptoInputParcel cryptoInput) {
+    @NonNull
-        return null;
+    public abstract OperationResult execute(T input, CryptoInputParcel cryptoInput);
-    }
 
     public void updateProgress(int message, int current, int total) {
         if (mProgressable != null) {

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/CertifyOperation.java

@@ -18,10 +18,9 @@
 package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
-import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.keyimport.HkpKeyserver;
-import org.sufficientlysecure.keychain.keyimport.Keyserver;
 import org.sufficientlysecure.keychain.operations.results.CertifyResult;
 import org.sufficientlysecure.keychain.operations.results.ExportResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
@@ -44,7 +43,6 @@ import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
 import org.sufficientlysecure.keychain.service.input.RequiredInputParcel.NfcSignOperationsBuilder;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
-import org.sufficientlysecure.keychain.util.ParcelableProxy;
 import org.sufficientlysecure.keychain.util.Passphrase;
 import org.sufficientlysecure.keychain.util.Preferences;
 import org.sufficientlysecure.keychain.util.orbot.OrbotHelper;
@@ -69,6 +67,7 @@ public class CertifyOperation extends BaseOperation<CertifyActionsParcel> {
         super(context, providerHelper, progressable, cancelled);
     }
 
+    @NonNull
     @Override
     public CertifyResult execute(CertifyActionsParcel parcel, CryptoInputParcel cryptoInput) {
 

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ConsolidateOperation.java

@@ -20,6 +20,7 @@
 package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.operations.results.ConsolidateResult;
 import org.sufficientlysecure.keychain.pgp.Progressable;
@@ -34,6 +35,7 @@ public class ConsolidateOperation extends BaseOperation<ConsolidateInputParcel>
         super(context, providerHelper, progressable);
     }
 
+    @NonNull
     @Override
     public ConsolidateResult execute(ConsolidateInputParcel consolidateInputParcel,
                                      CryptoInputParcel cryptoInputParcel) {

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/DeleteOperation.java

@@ -18,6 +18,7 @@
 package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.operations.results.ConsolidateResult;
 import org.sufficientlysecure.keychain.operations.results.DeleteResult;
@@ -45,6 +46,7 @@ public class DeleteOperation extends BaseOperation<DeleteKeyringParcel> {
         super(context, providerHelper, progressable);
     }
 
+    @NonNull
     @Override
     public DeleteResult execute(DeleteKeyringParcel deleteKeyringParcel,
                                 CryptoInputParcel cryptoInputParcel) {

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/EditKeyOperation.java

@@ -18,6 +18,7 @@
 package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.operations.results.EditKeyResult;
@@ -57,6 +58,7 @@ public class EditKeyOperation extends BaseOperation<SaveKeyringParcel> {
         super(context, providerHelper, progressable, cancelled);
     }
 
+    @NonNull
     public OperationResult execute(SaveKeyringParcel saveParcel, CryptoInputParcel cryptoInput) {
 
         OperationLog log = new OperationLog();

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ExportOperation.java

@@ -21,6 +21,7 @@ package org.sufficientlysecure.keychain.operations;
 import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 
 import org.spongycastle.bcpg.ArmoredOutputStream;
 import org.sufficientlysecure.keychain.Constants;
@@ -329,6 +330,7 @@ public class ExportOperation extends BaseOperation<ExportKeyringParcel> {
 
     }
 
+    @NonNull
     public ExportResult execute(ExportKeyringParcel exportInput, CryptoInputParcel cryptoInput) {
         switch (exportInput.mExportType) {
             case UPLOAD_KEYSERVER: {
@@ -364,8 +366,8 @@ public class ExportOperation extends BaseOperation<ExportKeyringParcel> {
                 return exportToUri(exportInput.mMasterKeyIds, exportInput.mExportSecret,
                         exportInput.mOutputUri);
             }
-            default: { // can't happen
+            default: { // can never happen, all enum types must be handled above
-                return null;
+                throw new AssertionError("must not happen, this is a bug!");
             }
         }
     }

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/ImportOperation.java

@@ -18,7 +18,24 @@
 
 package org.sufficientlysecure.keychain.operations;
 
+
+import java.io.IOException;
+import java.net.Proxy;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.concurrent.Callable;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorCompletionService;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.SynchronousQueue;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.R;
@@ -28,7 +45,6 @@ import org.sufficientlysecure.keychain.keyimport.Keyserver;
 import org.sufficientlysecure.keychain.keyimport.ParcelableKeyRing;
 import org.sufficientlysecure.keychain.operations.results.ConsolidateResult;
 import org.sufficientlysecure.keychain.operations.results.ImportKeyResult;
-import org.sufficientlysecure.keychain.operations.results.InputPendingResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.OperationLog;
@@ -48,21 +64,6 @@ import org.sufficientlysecure.keychain.util.Preferences;
 import org.sufficientlysecure.keychain.util.ProgressScaler;
 import org.sufficientlysecure.keychain.util.orbot.OrbotHelper;
 
-import java.io.IOException;
-import java.net.Proxy;
-import java.util.ArrayList;
-import java.util.HashSet;
-import java.util.Iterator;
-import java.util.List;
-import java.util.concurrent.Callable;
-import java.util.concurrent.ExecutionException;
-import java.util.concurrent.ExecutorCompletionService;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.SynchronousQueue;
-import java.util.concurrent.ThreadPoolExecutor;
-import java.util.concurrent.TimeUnit;
-import java.util.concurrent.atomic.AtomicBoolean;
-
 /**
  * An operation class which implements high level import
  * operations.
@@ -118,6 +119,7 @@ public class ImportOperation extends BaseOperation<ImportKeyringParcel> {
 
     }
 
+    @NonNull
     public ImportKeyResult serialKeyRingImport(ParcelableFileCache<ParcelableKeyRing> cache,
                                                String keyServerUri, Proxy proxy) {
 
@@ -148,8 +150,8 @@ public class ImportOperation extends BaseOperation<ImportKeyringParcel> {
      * @param keyServerUri contains uri of keyserver to import from, if it is an import from cloud
      * @param progressable Allows multi-threaded import to supply a progressable that ignores the
      *                     progress of a single key being imported
-     * @return
      */
+    @NonNull
     public ImportKeyResult serialKeyRingImport(Iterator<ParcelableKeyRing> entries, int num,
                                                String keyServerUri, Progressable progressable,
                                                Proxy proxy) {
@@ -380,6 +382,7 @@ public class ImportOperation extends BaseOperation<ImportKeyringParcel> {
                 importedMasterKeyIdsArray);
     }
 
+    @NonNull
     @Override
     public OperationResult execute(ImportKeyringParcel importInput, CryptoInputParcel cryptoInput) {
         ArrayList<ParcelableKeyRing> keyList = importInput.mKeyList;
@@ -426,6 +429,7 @@ public class ImportOperation extends BaseOperation<ImportKeyringParcel> {
         return result;
     }
 
+    @NonNull
     private ImportKeyResult multiThreadedKeyImport(Iterator<ParcelableKeyRing> keyListIterator,
                                                    int totKeys, final String keyServer,
                                                    final Proxy proxy) {
@@ -441,7 +445,7 @@ public class ImportOperation extends BaseOperation<ImportKeyringParcel> {
                     new SynchronousQueue<Runnable>());
 
             ExecutorCompletionService<ImportKeyResult> importCompletionService =
-                    new ExecutorCompletionService(importExecutor);
+                    new ExecutorCompletionService<>(importExecutor);
 
             while (keyListIterator.hasNext()) { // submit all key rings to be imported
 

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/KeybaseVerificationOperation.java

@@ -19,7 +19,15 @@
 
 package org.sufficientlysecure.keychain.operations;
 
+
+import java.io.ByteArrayInputStream;
+import java.io.InputStream;
+import java.net.Proxy;
+import java.util.ArrayList;
+import java.util.List;
+
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import com.textuality.keybase.lib.Proof;
 import com.textuality.keybase.lib.prover.Prover;
@@ -32,7 +40,6 @@ import de.measite.minidns.record.TXT;
 import org.json.JSONObject;
 import org.spongycastle.openpgp.PGPUtil;
 import org.sufficientlysecure.keychain.R;
-import org.sufficientlysecure.keychain.operations.results.CertifyResult;
 import org.sufficientlysecure.keychain.operations.results.DecryptVerifyResult;
 import org.sufficientlysecure.keychain.operations.results.KeybaseVerificationResult;
 import org.sufficientlysecure.keychain.operations.results.OperationResult;
@@ -46,12 +53,6 @@ import org.sufficientlysecure.keychain.service.input.RequiredInputParcel;
 import org.sufficientlysecure.keychain.util.Preferences;
 import org.sufficientlysecure.keychain.util.orbot.OrbotHelper;
 
-import java.io.ByteArrayInputStream;
-import java.io.InputStream;
-import java.net.Proxy;
-import java.util.ArrayList;
-import java.util.List;
-
 public class KeybaseVerificationOperation extends BaseOperation<KeybaseVerificationParcel> {
 
     public KeybaseVerificationOperation(Context context, ProviderHelper providerHelper,
@@ -59,6 +60,7 @@ public class KeybaseVerificationOperation extends BaseOperation<KeybaseVerificat
         super(context, providerHelper, progressable);
     }
 
+    @NonNull
     @Override
     public KeybaseVerificationResult execute(KeybaseVerificationParcel keybaseInput,
                                              CryptoInputParcel cryptoInput) {
@@ -113,7 +115,7 @@ public class KeybaseVerificationOperation extends BaseOperation<KeybaseVerificat
                     return new KeybaseVerificationResult(OperationResult.RESULT_ERROR, log);
                 }
                 Record[] records = dnsQuery.getAnswers();
-                List<List<byte[]>> extents = new ArrayList<List<byte[]>>();
+                List<List<byte[]>> extents = new ArrayList<>();
                 for (Record r : records) {
                     Data d = r.getPayload();
                     if (d instanceof TXT) {

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/PromoteKeyOperation.java

@@ -17,7 +17,11 @@
 
 package org.sufficientlysecure.keychain.operations;
 
+
+import java.util.concurrent.atomic.AtomicBoolean;
+
 import android.content.Context;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.R;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
@@ -36,8 +40,6 @@ import org.sufficientlysecure.keychain.service.input.CryptoInputParcel;
 import org.sufficientlysecure.keychain.ui.util.KeyFormattingUtils;
 import org.sufficientlysecure.keychain.util.ProgressScaler;
 
-import java.util.concurrent.atomic.AtomicBoolean;
-
 /** An operation which promotes a public key ring to a secret one.
  *
  * This operation can only be applied to public key rings where no secret key
@@ -52,18 +54,10 @@ public class PromoteKeyOperation extends BaseOperation<PromoteKeyringParcel> {
         super(context, providerHelper, progressable, cancelled);
     }
 
+    @NonNull
     @Override
     public PromoteKeyResult execute(PromoteKeyringParcel promoteKeyringParcel,
                                     CryptoInputParcel cryptoInputParcel) {
-        // Input
-        long masterKeyId = promoteKeyringParcel.mKeyRingId;
-        byte[] cardAid = promoteKeyringParcel.mCardAid;
-        long[] subKeyIds = promoteKeyringParcel.mSubKeyIds;
-
-        return execute(masterKeyId, cardAid, subKeyIds);
-    }
-
-    public PromoteKeyResult execute(long masterKeyId, byte[] cardAid, long[] subKeyIds) {
 
         OperationLog log = new OperationLog();
         log.add(LogType.MSG_PR, 0);
@@ -74,17 +68,17 @@ public class PromoteKeyOperation extends BaseOperation<PromoteKeyringParcel> {
             try {
 
                 log.add(LogType.MSG_PR_FETCHING, 1,
-                        KeyFormattingUtils.convertKeyIdToHex(masterKeyId));
+                        KeyFormattingUtils.convertKeyIdToHex(promoteKeyringParcel.mKeyRingId));
                 CanonicalizedPublicKeyRing pubRing =
-                        mProviderHelper.getCanonicalizedPublicKeyRing(masterKeyId);
+                        mProviderHelper.getCanonicalizedPublicKeyRing(promoteKeyringParcel.mKeyRingId);
 
-                if (subKeyIds == null) {
+                if (promoteKeyringParcel.mSubKeyIds == null) {
                     log.add(LogType.MSG_PR_ALL, 1);
                 } else {
                     // sort for binary search
                     for (CanonicalizedPublicKey key : pubRing.publicKeyIterator()) {
                         long subKeyId = key.getKeyId();
-                        if (naiveIndexOf(subKeyIds, subKeyId) != null) {
+                        if (naiveIndexOf(promoteKeyringParcel.mSubKeyIds, subKeyId) != null) {
                             log.add(LogType.MSG_PR_SUBKEY_MATCH, 1,
                                     KeyFormattingUtils.convertKeyIdToHex(subKeyId));
                         } else {
@@ -95,7 +89,8 @@ public class PromoteKeyOperation extends BaseOperation<PromoteKeyringParcel> {
                 }
 
                 // create divert-to-card secret key from public key
-                promotedRing = pubRing.createDivertSecretRing(cardAid, subKeyIds);
+                promotedRing = pubRing.createDivertSecretRing(promoteKeyringParcel.mCardAid,
+                        promoteKeyringParcel.mSubKeyIds);
 
             } catch (NotFoundException e) {
                 log.add(LogType.MSG_PR_ERROR_KEY_NOT_FOUND, 2);

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/operations/SignEncryptOperation.java

@@ -19,6 +19,7 @@ package org.sufficientlysecure.keychain.operations;
 
 import android.content.Context;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 
 import org.sufficientlysecure.keychain.Constants;
 import org.sufficientlysecure.keychain.operations.results.OperationResult.LogType;
@@ -62,6 +63,7 @@ public class SignEncryptOperation extends BaseOperation<SignEncryptParcel> {
         super(context, providerHelper, progressable, cancelled);
     }
 
+    @NonNull
     public SignEncryptResult execute(SignEncryptParcel input, CryptoInputParcel cryptoInput) {
 
         OperationLog log = new OperationLog();

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/pgp/PgpDecryptVerify.java

@@ -19,6 +19,7 @@
 package org.sufficientlysecure.keychain.pgp;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 import android.webkit.MimeTypeMap;
 
 import org.openintents.openpgp.OpenPgpMetadata;
@@ -80,9 +81,8 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
         super(context, providerHelper, progressable);
     }
 
-    /**
+    /** Decrypts and/or verifies data based on parameters of PgpDecryptVerifyInputParcel. */
-     * Decrypts and/or verifies data based on parameters of class
+    @NonNull
-     */
     public DecryptVerifyResult execute(PgpDecryptVerifyInputParcel input, CryptoInputParcel cryptoInput) {
         InputData inputData;
         OutputStream outputStream;
@@ -96,8 +96,10 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
                 long inputSize = FileHelper.getFileSize(mContext, input.getInputUri(), 0);
                 inputData = new InputData(inputStream, inputSize);
             } catch (FileNotFoundException e) {
-                Log.e(Constants.TAG, "File not found at " + input.getInputUri(), e);
+                Log.e(Constants.TAG, "URI could not be opened: " + input.getInputUri(), e);
-                return null;
+                OperationLog log = new OperationLog();
+                log.add(LogType.MSG_DC_ERROR_IO, 1);
+                return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
             }
         }
 
@@ -107,8 +109,10 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
             try {
                 outputStream = mContext.getContentResolver().openOutputStream(input.getOutputUri());
             } catch (FileNotFoundException e) {
-                e.printStackTrace();
+                Log.e(Constants.TAG, "URI could not be opened: " + input.getOutputUri(), e);
-                return null;
+                OperationLog log = new OperationLog();
+                log.add(LogType.MSG_DC_ERROR_IO, 1);
+                return new DecryptVerifyResult(DecryptVerifyResult.RESULT_ERROR, log);
             }
         }
 
@@ -122,11 +126,13 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
 
     }
 
+    @NonNull
     public DecryptVerifyResult execute(PgpDecryptVerifyInputParcel input, CryptoInputParcel cryptoInput,
             InputData inputData, OutputStream outputStream) {
         return executeInternal(input, cryptoInput, inputData, outputStream);
     }
 
+    @NonNull
     private DecryptVerifyResult executeInternal(PgpDecryptVerifyInputParcel input, CryptoInputParcel cryptoInput,
             InputData inputData, OutputStream outputStream) {
         try {
@@ -169,9 +175,8 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
         }
     }
 
-    /**
+    /**Verify signed plaintext data (PGP/INLINE). */
-     * Verify Keybase.io style signed literal data
+    @NonNull
-     */
     private DecryptVerifyResult verifySignedLiteralData(
             PgpDecryptVerifyInputParcel input, InputStream in, OutputStream out, int indent)
             throws IOException, PGPException {
@@ -301,9 +306,8 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
     }
 
 
-    /**
+    /** Decrypt and/or verify binary or ascii armored pgp data. */
-     * Decrypt and/or verifies binary or ascii armored pgp
+    @NonNull
-     */
     private DecryptVerifyResult decryptVerify(
             PgpDecryptVerifyInputParcel input, CryptoInputParcel cryptoInput,
             InputStream in, OutputStream out, int indent) throws IOException, PGPException {
@@ -843,6 +847,7 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
      * The method is heavily based on
      * pg/src/main/java/org/spongycastle/openpgp/examples/ClearSignedFileProcessor.java
      */
+    @NonNull
     private DecryptVerifyResult verifyCleartextSignature(
             ArmoredInputStream aIn, OutputStream outputStream, int indent) throws IOException, PGPException {
 
@@ -950,6 +955,7 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
         return result;
     }
 
+    @NonNull
     private DecryptVerifyResult verifyDetachedSignature(
             PgpDecryptVerifyInputParcel input, InputData inputData, OutputStream out, int indent)
             throws IOException, PGPException {
@@ -1042,7 +1048,9 @@ public class PgpDecryptVerify extends BaseOperation<PgpDecryptVerifyInputParcel>
         return result;
     }
 
-    private PGPSignature processPGPSignatureList(PGPSignatureList sigList, OpenPgpSignatureResultBuilder signatureResultBuilder) throws PGPException {
+    private PGPSignature processPGPSignatureList(
+            PGPSignatureList sigList, OpenPgpSignatureResultBuilder signatureResultBuilder)
+            throws PGPException {
         CanonicalizedPublicKeyRing signingRing = null;
         CanonicalizedPublicKey signingKey = null;
         int signatureIndex = -1;

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/provider/ProviderHelper.java

@@ -1060,6 +1060,7 @@ public class ProviderHelper {
 
     }
 
+    @NonNull
     public ConsolidateResult consolidateDatabaseStep1(Progressable progress) {
 
         OperationLog log = new OperationLog();
@@ -1205,12 +1206,14 @@ public class ProviderHelper {
         return consolidateDatabaseStep2(log, indent, progress, false);
     }
 
+    @NonNull
     public ConsolidateResult consolidateDatabaseStep2(Progressable progress) {
         return consolidateDatabaseStep2(new OperationLog(), 0, progress, true);
     }
 
     private static boolean mConsolidateCritical = false;
 
+    @NonNull
     private ConsolidateResult consolidateDatabaseStep2(
             OperationLog log, int indent, Progressable progress, boolean recovery) {
 

OpenKeychain/src/main/java/org/sufficientlysecure/keychain/ui/base/CryptoOperationHelper.java

@@ -314,14 +314,6 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
         cryptoOperation(new CryptoInputParcel());
     }
 
-    protected void onCryptoOperationResult(S result) {
-        if (result.success()) {
-            mCallback.onCryptoOperationSuccess(result);
-        } else {
-            mCallback.onCryptoOperationError(result);
-        }
-    }
-
     public void onHandleResult(OperationResult result, CryptoInputParcel oldCryptoInput) {
         Log.d(Constants.TAG, "Handling result in OperationHelper success: " + result.success());
 
@@ -338,8 +330,13 @@ public class CryptoOperationHelper<T extends Parcelable, S extends OperationResu
         dismissProgress();
 
         try {
-            // noinspection unchecked, because type erasure :(
+            if (result.success()) {
-            onCryptoOperationResult((S) result);
+                // noinspection unchecked, because type erasure :(
+                mCallback.onCryptoOperationSuccess((S) result);
+            } else {
+                // noinspection unchecked, because type erasure :(
+                mCallback.onCryptoOperationError((S) result);
+            }
         } catch (ClassCastException e) {
             throw new AssertionError("bad return class ("
                     + result.getClass().getSimpleName() + "), this is a programming error!");