Refactor CleartextSignatureProcessor to allow reuse in DetachInbandSignatureAndMessage

sop-java/src/main/java/sop/Ready.java

@@ -21,8 +21,21 @@ import java.io.OutputStream;
 
 public abstract class Ready {
 
+    /**
+     * Write the data to the provided output stream.
+     *
+     * @param outputStream output stream
+     * @throws IOException in case of an IO error
+     */
     public abstract void writeTo(OutputStream outputStream) throws IOException;
 
+    /**
+     * Return the data as a byte array by writing it to a {@link ByteArrayOutputStream} first and then returning
+     * the array.
+     *
+     * @return data as byte array
+     * @throws IOException in case of an IO error
+     */
     public byte[] getBytes() throws IOException {
         ByteArrayOutputStream bytes = new ByteArrayOutputStream();
         writeTo(bytes);

sop-java/src/main/java/sop/ReadyWithResult.java

@@ -23,6 +23,16 @@ import sop.exception.SOPGPException;
 
 public abstract class ReadyWithResult<T> {
 
+    /**
+     * Write the data eg. decrypted plaintext to the provided output stream and return the result of the
+     * processing operation.
+     *
+     * @param outputStream output stream
+     * @return result, eg. signatures
+     *
+     * @throws IOException in case of an IO error
+     * @throws SOPGPException.NoSignature
+     */
     public abstract T writeTo(OutputStream outputStream) throws IOException, SOPGPException.NoSignature;
 
     public ByteArrayAndResult<T> toBytes() throws IOException, SOPGPException.NoSignature {

sop-java/src/main/java/sop/SOP.java

@@ -18,6 +18,7 @@ package sop;
 import sop.operation.Armor;
 import sop.operation.Dearmor;
 import sop.operation.Decrypt;
+import sop.operation.DetachInbandSignatureAndMessage;
 import sop.operation.Encrypt;
 import sop.operation.ExtractCert;
 import sop.operation.GenerateKey;
@@ -100,4 +101,6 @@ public interface SOP {
      * @return builder instance
      */
     Dearmor dearmor();
+
+    DetachInbandSignatureAndMessage detachInbandSignatureAndMessage();
 }

sop-java/src/main/java/sop/Signatures.java

@@ -0,0 +1,32 @@
+/*
+ * Copyright 2021 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sop;
+
+import java.io.IOException;
+import java.io.OutputStream;
+
+public abstract class Signatures extends Ready {
+
+    /**
+     * Write OpenPGP signatures to the provided output stream.
+     *
+     * @param signatureOutputStream output stream
+     * @throws IOException in case of an IO error
+     */
+    @Override
+    public abstract void writeTo(OutputStream signatureOutputStream) throws IOException;
+
+}

sop-java/src/main/java/sop/operation/DetachInbandSignatureAndMessage.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2021 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package sop.operation;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import sop.ReadyWithResult;
+import sop.Signatures;
+
+public interface DetachInbandSignatureAndMessage {
+
+    DetachInbandSignatureAndMessage noArmor();
+
+    ReadyWithResult<Signatures> message(InputStream messageInputStream) throws IOException;
+
+}