From fb235d78109e2e0fc2c4ddd6e75efcbd3dd3613e Mon Sep 17 00:00:00 2001
From: Paul Schaub <vanitasvitae@fsfe.org>
Date: Fri, 4 Aug 2023 17:34:52 +0200
Subject: [PATCH] Kotlin conversion: HashAlgorithmNegotiator

---
 .../negotiation/HashAlgorithmNegotiator.java  | 70 ------------------
 .../negotiation/HashAlgorithmNegotiator.kt    | 71 +++++++++++++++++++
 2 files changed, 71 insertions(+), 70 deletions(-)
 delete mode 100644 pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.java
 create mode 100644 pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.kt

diff --git a/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.java b/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.java
deleted file mode 100644
index 18fe53f9..00000000
--- a/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.java
+++ /dev/null
@@ -1,70 +0,0 @@
-// SPDX-FileCopyrightText: 2021 Paul Schaub <vanitasvitae@fsfe.org>
-//
-// SPDX-License-Identifier: Apache-2.0
-
-package org.pgpainless.algorithm.negotiation;
-
-import java.util.Set;
-
-import org.pgpainless.algorithm.HashAlgorithm;
-import org.pgpainless.policy.Policy;
-
-/**
- * Interface for a class that negotiates {@link HashAlgorithm HashAlgorithms}.
- *
- * You can provide your own implementation using custom logic by implementing the
- * {@link #negotiateHashAlgorithm(Set)} method.
- */
-public interface HashAlgorithmNegotiator {
-
-    /**
-     * Pick one {@link HashAlgorithm} from the ordered set of acceptable algorithms.
-     *
-     * @param orderedHashAlgorithmPreferencesSet hash algorithm preferences
-     * @return picked algorithms
-     */
-    HashAlgorithm negotiateHashAlgorithm(Set<HashAlgorithm> orderedHashAlgorithmPreferencesSet);
-
-    /**
-     * Return an instance that negotiates {@link HashAlgorithm HashAlgorithms} used for non-revocation signatures
-     * based on the given {@link Policy}.
-     *
-     * @param policy algorithm policy
-     * @return negotiator
-     */
-    static HashAlgorithmNegotiator negotiateSignatureHashAlgorithm(Policy policy) {
-        return negotiateByPolicy(policy.getSignatureHashAlgorithmPolicy());
-    }
-
-    /**
-     * Return an instance that negotiates {@link HashAlgorithm HashAlgorithms} used for revocation signatures
-     * based on the given {@link Policy}.
-     *
-     * @param policy algorithm policy
-     * @return negotiator
-     */
-    static HashAlgorithmNegotiator negotiateRevocationSignatureAlgorithm(Policy policy) {
-        return negotiateByPolicy(policy.getRevocationSignatureHashAlgorithmPolicy());
-    }
-
-    /**
-     * Return an instance that negotiates {@link HashAlgorithm HashAlgorithms} based on the given
-     * {@link Policy.HashAlgorithmPolicy}.
-     *
-     * @param hashAlgorithmPolicy algorithm policy for hash algorithms
-     * @return negotiator
-     */
-    static HashAlgorithmNegotiator negotiateByPolicy(Policy.HashAlgorithmPolicy hashAlgorithmPolicy) {
-        return new HashAlgorithmNegotiator() {
-            @Override
-            public HashAlgorithm negotiateHashAlgorithm(Set<HashAlgorithm> orderedPreferencesSet) {
-                for (HashAlgorithm preference : orderedPreferencesSet) {
-                    if (hashAlgorithmPolicy.isAcceptable(preference)) {
-                        return preference;
-                    }
-                }
-                return hashAlgorithmPolicy.defaultHashAlgorithm();
-            }
-        };
-    }
-}
diff --git a/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.kt b/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.kt
new file mode 100644
index 00000000..98cbe522
--- /dev/null
+++ b/pgpainless-core/src/main/java/org/pgpainless/algorithm/negotiation/HashAlgorithmNegotiator.kt
@@ -0,0 +1,71 @@
+// SPDX-FileCopyrightText: 2023 Paul Schaub <vanitasvitae@fsfe.org>
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package org.pgpainless.algorithm.negotiation
+
+import org.pgpainless.algorithm.HashAlgorithm
+import org.pgpainless.policy.Policy
+
+/**
+ * Interface for a class that negotiates [HashAlgorithms][HashAlgorithm].
+ *
+ * You can provide your own implementation using custom logic by implementing the
+ * [negotiateHashAlgorithm(Set)] method.
+ */
+interface HashAlgorithmNegotiator {
+
+    /**
+     * Pick one [HashAlgorithm] from the ordered set of acceptable algorithms.
+     *
+     * @param orderedPrefs hash algorithm preferences
+     * @return picked algorithms
+     */
+    fun negotiateHashAlgorithm(orderedPrefs: Set<HashAlgorithm>): HashAlgorithm
+
+    companion object {
+
+        /**
+         * Return an instance that negotiates [HashAlgorithms][HashAlgorithm] used for non-revocation signatures
+         * based on the given [Policy].
+         *
+         * @param policy algorithm policy
+         * @return negotiator
+         */
+        @JvmStatic
+        fun negotiateSignatureHashAlgorithm(policy: Policy): HashAlgorithmNegotiator {
+            return negotiateByPolicy(policy.signatureHashAlgorithmPolicy)
+        }
+
+        /**
+         * Return an instance that negotiates [HashAlgorithms][HashAlgorithm] used for revocation signatures
+         * based on the given [Policy].
+         *
+         * @param policy algorithm policy
+         * @return negotiator
+         */
+        @JvmStatic
+        fun negotiateRevocationSignatureAlgorithm(policy: Policy): HashAlgorithmNegotiator {
+            return negotiateByPolicy(policy.revocationSignatureHashAlgorithmPolicy)
+        }
+
+        /**
+         * Return an instance that negotiates [HashAlgorithms][HashAlgorithm] based on the given
+         * [Policy.HashAlgorithmPolicy].
+         *
+         * @param hashAlgorithmPolicy algorithm policy for hash algorithms
+         * @return negotiator
+         */
+        @JvmStatic
+        fun negotiateByPolicy(hashAlgorithmPolicy: Policy.HashAlgorithmPolicy): HashAlgorithmNegotiator {
+            return object: HashAlgorithmNegotiator {
+                override fun negotiateHashAlgorithm(orderedPrefs: Set<HashAlgorithm>): HashAlgorithm {
+                    return orderedPrefs.firstOrNull {
+                        hashAlgorithmPolicy.isAcceptable(it)
+                    } ?: hashAlgorithmPolicy.defaultHashAlgorithm()
+                }
+
+            }
+        }
+    }
+}
\ No newline at end of file