WIP: Play around with TeeInputStreams

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/OpenPgpMessageInputStream.java

@@ -343,7 +343,8 @@ public class OpenPgpMessageInputStream extends InputStream {
         return null;
     }
 
-    private PGPOnePassSignatureList readOnePassSignatures() throws IOException {
+    private PGPOnePassSignatureListWrapper readOnePassSignatures() throws IOException {
+        List<Boolean> encapsulating = new ArrayList<>();
         ByteArrayOutputStream buf = new ByteArrayOutputStream();
         BCPGOutputStream bcpgOut = new BCPGOutputStream(buf);
         int tag;
@@ -351,14 +352,16 @@ public class OpenPgpMessageInputStream extends InputStream {
             Packet packet = bcpgIn.readPacket();
             if (tag == PacketTags.ONE_PASS_SIGNATURE) {
                 OnePassSignaturePacket sigPacket = (OnePassSignaturePacket) packet;
-                sigPacket.encode(bcpgOut);
+                byte[] bytes = sigPacket.getEncoded();
+                encapsulating.add(bytes[bytes.length - 1] == 1);
+                bcpgOut.write(bytes);
             }
         }
         bcpgOut.close();
 
         PGPObjectFactory objectFactory = ImplementationFactory.getInstance().getPGPObjectFactory(buf.toByteArray());
         PGPOnePassSignatureList signatureList = (PGPOnePassSignatureList) objectFactory.nextObject();
-        return signatureList;
+        return new PGPOnePassSignatureListWrapper(signatureList, encapsulating);
     }
 
     private PGPSignatureList readSignatures() throws IOException {
@@ -490,6 +493,26 @@ public class OpenPgpMessageInputStream extends InputStream {
         }
     }
 
+    /**
+     * Workaround for BC not exposing, whether an OPS is encapsulating or not.
+     * TODO: Remove once our PR is merged
+     *
+     * @see <a href="https://github.com/bcgit/bc-java/pull/1232">PR against BC</a>
+     */
+    private static class PGPOnePassSignatureListWrapper {
+        private final PGPOnePassSignatureList list;
+        private final List<Boolean> encapsulating;
+
+        public PGPOnePassSignatureListWrapper(PGPOnePassSignatureList signatures, List<Boolean> encapsulating) {
+            this.list = signatures;
+            this.encapsulating = encapsulating;
+        }
+
+        public int size() {
+            return list.size();
+        }
+    }
+
     private static class Signatures {
         final ConsumerOptions options;
         List<PGPSignature> detachedSignatures = new ArrayList<>();
@@ -521,9 +544,9 @@ public class OpenPgpMessageInputStream extends InputStream {
             }
         }
 
-        void addOnePassSignatures(PGPOnePassSignatureList signatures) {
+        void addOnePassSignatures(PGPOnePassSignatureListWrapper signatures) {
             System.out.println("Adding " + signatures.size() + " OPSs");
-            for (PGPOnePassSignature ops : signatures) {
+            for (PGPOnePassSignature ops : signatures.list) {
                 PGPPublicKeyRing certificate = findCertificate(ops.getKeyID());
                 initialize(ops, certificate);
                 this.onePassSignatures.add(ops);

pgpainless-core/src/main/java/org/pgpainless/decryption_verification/TeeBCPGInputStream.java

@@ -0,0 +1,35 @@
+package org.pgpainless.decryption_verification;
+
+import org.bouncycastle.bcpg.BCPGInputStream;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+public class TeeBCPGInputStream extends BCPGInputStream {
+
+    private final OutputStream out;
+
+    public TeeBCPGInputStream(InputStream in, OutputStream outputStream) {
+        super(in);
+        this.out = outputStream;
+    }
+
+    @Override
+    public int read() throws IOException {
+        int r = super.read();
+        if (r != -1) {
+            out.write(r);
+        }
+        return r;
+    }
+
+    @Override
+    public int read(byte[] buf, int off, int len) throws IOException {
+        int r = super.read(buf, off, len);
+        if (r > 0) {
+            out.write(buf, off, r);
+        }
+        return r;
+    }
+}

pgpainless-core/src/test/java/org/pgpainless/decryption_verification/TeeBCPGInputStreamTest.java

@@ -0,0 +1,58 @@
+package org.pgpainless.decryption_verification;
+
+import org.bouncycastle.bcpg.ArmoredInputStream;
+import org.bouncycastle.bcpg.ArmoredOutputStream;
+import org.bouncycastle.bcpg.BCPGInputStream;
+import org.bouncycastle.bcpg.Packet;
+import org.bouncycastle.openpgp.PGPCompressedData;
+import org.bouncycastle.openpgp.PGPException;
+import org.junit.jupiter.api.Test;
+import org.pgpainless.algorithm.OpenPgpPacket;
+import org.pgpainless.util.ArmoredInputStreamFactory;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.charset.StandardCharsets;
+
+public class TeeBCPGInputStreamTest {
+
+    private static final String INBAND_SIGNED = "-----BEGIN PGP MESSAGE-----\n" +
+            "Version: PGPainless\n" +
+            "\n" +
+            "owGbwMvMyCUWdXSHvVTUtXbG0yJJDCDgkZqTk6+jEJ5flJOiyNVRysIoxsXAxsqU\n" +
+            "GDiVjUGRUwCmQUyRRWnOn9Z/PIseF3Yz6cCEL05nZDj1OClo75WVTjNmJPemW6qV\n" +
+            "6ki//1K1++2s0qTP+0N11O4z/BVLDDdxnmQryS+5VXjBX7/0Hxnm/eqeX6Zum35r\n" +
+            "M8e7ufwA\n" +
+            "=RDiy\n" +
+            "-----END PGP MESSAGE-----";
+
+    @Test
+    public void test() throws IOException, PGPException {
+        ByteArrayOutputStream out = new ByteArrayOutputStream();
+        ArmoredOutputStream armorOut = new ArmoredOutputStream(out);
+
+        ByteArrayInputStream bytesIn = new ByteArrayInputStream(INBAND_SIGNED.getBytes(StandardCharsets.UTF_8));
+        ArmoredInputStream armorIn = ArmoredInputStreamFactory.get(bytesIn);
+        BCPGInputStream bcpgIn = new BCPGInputStream(armorIn);
+        TeeBCPGInputStream teeIn = new TeeBCPGInputStream(bcpgIn, armorOut);
+
+        ByteArrayOutputStream nestedOut = new ByteArrayOutputStream();
+        ArmoredOutputStream nestedArmorOut = new ArmoredOutputStream(nestedOut);
+
+        PGPCompressedData compressedData = new PGPCompressedData(teeIn);
+        InputStream nestedStream = compressedData.getDataStream();
+        BCPGInputStream nestedBcpgIn = new BCPGInputStream(nestedStream);
+        TeeBCPGInputStream nestedTeeIn = new TeeBCPGInputStream(nestedBcpgIn, nestedArmorOut);
+
+        int tag;
+        while ((tag = nestedTeeIn.nextPacketTag()) != -1) {
+            System.out.println(OpenPgpPacket.requireFromTag(tag));
+            Packet packet = nestedTeeIn.readPacket();
+        }
+
+        nestedArmorOut.close();
+        System.out.println(nestedOut);
+    }
+}