Module structure

pgp-certificate-store/build.gradle

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+plugins {
+    id 'java-library'
+}
+
+group 'org.pgpainless'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation "org.junit.jupiter:junit-jupiter-api:$junitVersion"
+    testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
+
+    // Logging
+    testImplementation "ch.qos.logback:logback-classic:$logbackVersion"
+}
+
+test {
+    useJUnitPlatform()
+}

pgp-certificate-store/src/main/java/pgp/certificate_store/CertificateStore.java

@@ -0,0 +1,24 @@
+package pgp.certificate_store;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Iterator;
+
+public interface CertificateStore {
+
+    Item get(String identifier) throws IOException;
+
+    Item getIfChanged(String identifier, String tag) throws IOException;
+
+    Item insert(InputStream data, MergeCallback merge) throws IOException;
+
+    Item tryInsert(InputStream data, MergeCallback merge) throws IOException;
+
+    Item insertSpecial(String specialName, InputStream data, MergeCallback merge) throws IOException;
+
+    Item tryInsertSpecial(String specialName, InputStream data, MergeCallback merge) throws IOException;
+
+    Iterator<Item> items();
+
+    Iterator<String> fingerprints();
+}

pgp-certificate-store/src/main/java/pgp/certificate_store/Item.java

@@ -0,0 +1,43 @@
+package pgp.certificate_store;
+
+import java.io.InputStream;
+
+public class Item {
+
+    private final String fingerprint;
+    private final String tag;
+    private final InputStream data;
+
+    public Item(String fingerprint, String tag, InputStream data) {
+        this.fingerprint = fingerprint;
+        this.tag = tag;
+        this.data = data;
+    }
+
+    /**
+     * Return the fingerprint of the certificate.
+     *
+     * @return certificate fingerprint
+     */
+    public String getFingerprint() {
+        return fingerprint;
+    }
+
+    /**
+     * Return a tag used to check if the certificate was changed between retrievals.
+     *
+     * @return tag
+     */
+    public String getTag() {
+        return tag;
+    }
+
+    /**
+     * Return an {@link InputStream} containing the certificate data.
+     *
+     * @return data
+     */
+    public InputStream getData() {
+        return data;
+    }
+}

pgp-certificate-store/src/main/java/pgp/certificate_store/MergeCallback.java

@@ -0,0 +1,22 @@
+package pgp.certificate_store;
+
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Merge a given certificate (update) with an existing certificate.
+ */
+public interface MergeCallback {
+
+    /**
+     * Merge the given certificate data with the existing certificate and return the result.
+     *
+     * If no existing certificate is found (i.e. existing is null), this method returns the binary representation of data.
+     *
+     * @param data input stream containing the certificate
+     * @param existing optional input stream containing an already existing copy of the certificate
+     * @return output stream containing the binary representation of the merged certificate
+     */
+    OutputStream merge(InputStream data, InputStream existing);
+
+}