Use PGPPublicKeyRing.join(first, second) for proper MergeCallback

pgpainless-cert-d-cli/src/main/java/pgp/cert_d/cli/commands/DefaultMergeCallback.java

@@ -0,0 +1,85 @@
+// SPDX-FileCopyrightText: 2022 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package pgp.cert_d.cli.commands;
+
+import org.bouncycastle.openpgp.PGPException;
+import org.bouncycastle.openpgp.PGPPublicKey;
+import org.bouncycastle.openpgp.PGPPublicKeyRing;
+import org.pgpainless.PGPainless;
+import org.pgpainless.certificate_store.CertificateFactory;
+import org.pgpainless.key.OpenPgpFingerprint;
+import pgp.certificate_store.Certificate;
+import pgp.certificate_store.MergeCallback;
+
+import java.io.IOException;
+import java.util.Iterator;
+
+public class DefaultMergeCallback implements MergeCallback {
+
+    @Override
+    public Certificate merge(Certificate data, Certificate existing) throws IOException {
+        try {
+            PGPPublicKeyRing existingCert = PGPainless.readKeyRing().publicKeyRing(existing.getInputStream());
+            PGPPublicKeyRing updatedCert = PGPainless.readKeyRing().publicKeyRing(data.getInputStream());
+            PGPPublicKeyRing mergedCert = PGPPublicKeyRing.join(existingCert, updatedCert);
+
+            printOutDifferences(existingCert, mergedCert);
+
+            return CertificateFactory.certificateFromPublicKeyRing(mergedCert);
+        } catch (PGPException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    private void printOutDifferences(PGPPublicKeyRing existingCert, PGPPublicKeyRing mergedCert) {
+        int numSigsBefore = countSigs(existingCert);
+        int numSigsAfter = countSigs(mergedCert);
+        int newSigs = numSigsAfter - numSigsBefore;
+        int numUidsBefore = count(existingCert.getPublicKey().getUserIDs());
+        int numUidsAfter = count(mergedCert.getPublicKey().getUserIDs());
+        int newUids = numUidsAfter - numUidsBefore;
+
+        if (!existingCert.equals(mergedCert)) {
+            OpenPgpFingerprint fingerprint = OpenPgpFingerprint.of(mergedCert);
+            StringBuilder sb = new StringBuilder();
+            sb.append(String.format("Certificate %s has", fingerprint));
+            if (newSigs != 0) {
+                sb.append(String.format(" %d new signatures", newSigs));
+            }
+            if (newUids != 0) {
+                if (newSigs != 0) {
+                    sb.append(" and");
+                }
+                sb.append(String.format(" %d new UIDs", newUids));
+            }
+            if (newSigs == 0 && newUids == 0) {
+                sb.append(" changed");
+            }
+
+            // In this case it is okay to print to stdout, since we are a CLI app
+            // CHECKSTYLE:OFF
+            System.out.println(sb);
+            // CHECKSTYLE:ON
+        }
+    }
+
+    private static int countSigs(PGPPublicKeyRing keys) {
+        int numSigs = 0;
+        for (PGPPublicKey key : keys) {
+            numSigs += count(key.getSignatures());
+        }
+        return numSigs;
+    }
+
+    // TODO: Use CollectionUtils.count() once available
+    private static int count(Iterator<?> iterator) {
+        int num = 0;
+        while (iterator.hasNext()) {
+            iterator.next();
+            num++;
+        }
+        return num;
+    }
+}

pgpainless-cert-d-cli/src/main/java/pgp/cert_d/cli/commands/Import.java

@@ -4,8 +4,6 @@
 
 package pgp.cert_d.cli.commands;
 
-import java.io.IOException;
-
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import pgp.cert_d.cli.PGPCertDCli;
@@ -14,27 +12,19 @@ import pgp.certificate_store.MergeCallback;
 import pgp.certificate_store.exception.BadDataException;
 import picocli.CommandLine;
 
+import java.io.IOException;
+
 @CommandLine.Command(name = "import",
         description = "Import or update a certificate")
 public class Import implements Runnable {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(Import.class);
-
+    private final MergeCallback mergeCallback = new DefaultMergeCallback();
-    // TODO: Replace with proper merge callback
-    private final MergeCallback dummyMerge = new MergeCallback() {
-        @Override
-        public Certificate merge(Certificate data, Certificate existing) throws IOException {
-            return data;
-        }
-    };
 
     @Override
     public void run() {
         try {
-            Certificate certificate = PGPCertDCli.getCertificateDirectory().insertCertificate(System.in, dummyMerge);
+            Certificate certificate = PGPCertDCli.getCertificateDirectory().insertCertificate(System.in, mergeCallback);
-            // CHECKSTYLE:OFF
-            System.out.println(certificate.getFingerprint());
-            // CHECKSTYLE:ON
         } catch (IOException e) {
             LOGGER.error("IO-Error.", e);
             System.exit(-1);

pgpainless-cert-d-cli/src/main/java/pgp/cert_d/cli/commands/MultiImport.java

@@ -24,14 +24,7 @@ import java.io.IOException;
 public class MultiImport implements Runnable {
 
     private static final Logger LOGGER = LoggerFactory.getLogger(MultiImport.class);
-
+    private final MergeCallback dummyMerge = new DefaultMergeCallback();
-    // TODO: Replace with proper merge callback
-    private final MergeCallback dummyMerge = new MergeCallback() {
-        @Override
-        public Certificate merge(Certificate data, Certificate existing) throws IOException {
-            return data;
-        }
-    };
 
     @Override
     public void run() {
@@ -41,9 +34,6 @@ public class MultiImport implements Runnable {
                 ByteArrayInputStream certIn = new ByteArrayInputStream(cert.getEncoded());
                 Certificate certificate = PGPCertDCli.getCertificateDirectory()
                         .insertCertificate(certIn, dummyMerge);
-                // CHECKSTYLE:OFF
-                System.out.println(certificate.getFingerprint());
-                // CHECKSTYLE:ON
             }
         } catch (IOException e) {
             LOGGER.error("IO-Error.", e);