Add ObjectIdCacheSerializer

Change-Id: I0ed9b03112f75b8be055ecc7f673c0cca78dc975

java/com/google/gerrit/server/cache/serialize/ObjectIdCacheSerializer.java

@@ -0,0 +1,37 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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 com.google.gerrit.server.cache.serialize;
+
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
+
+public enum ObjectIdCacheSerializer implements CacheSerializer<ObjectId> {
+  INSTANCE;
+
+  @Override
+  public byte[] serialize(ObjectId object) {
+    byte[] buf = new byte[Constants.OBJECT_ID_LENGTH];
+    object.copyRawTo(buf, 0);
+    return buf;
+  }
+
+  @Override
+  public ObjectId deserialize(byte[] in) {
+    if (in == null || in.length != Constants.OBJECT_ID_LENGTH) {
+      throw new IllegalArgumentException("Failed to deserialize ObjectId");
+    }
+    return ObjectId.fromRaw(in);
+  }
+}

javatests/com/google/gerrit/server/cache/serialize/ObjectIdCacheSerializerTest.java

@@ -0,0 +1,56 @@
+// Copyright (C) 2018 The Android Open Source Project
+//
+// 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 com.google.gerrit.server.cache.serialize;
+
+import static com.google.common.truth.Truth.assertThat;
+import static com.google.common.truth.Truth.assert_;
+import static com.google.gerrit.server.cache.testing.CacheSerializerTestUtil.byteArray;
+
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+public class ObjectIdCacheSerializerTest {
+  @Test
+  public void serialize() {
+    ObjectId id = ObjectId.fromString("aabbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb");
+    byte[] serialized = ObjectIdCacheSerializer.INSTANCE.serialize(id);
+    assertThat(serialized)
+        .isEqualTo(
+            byteArray(
+                0xaa, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb,
+                0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0xbb));
+    assertThat(ObjectIdCacheSerializer.INSTANCE.deserialize(serialized)).isEqualTo(id);
+  }
+
+  @Test
+  public void deserializeInvalid() {
+    assertDeserializeFails(null);
+    assertDeserializeFails(byteArray());
+    assertDeserializeFails(byteArray(0xaa));
+    assertDeserializeFails(
+        byteArray(
+            0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
+            0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa));
+  }
+
+  private void assertDeserializeFails(byte[] bytes) {
+    try {
+      ObjectIdCacheSerializer.INSTANCE.deserialize(bytes);
+      assert_().fail("expected IllegalArgumentException");
+    } catch (IllegalArgumentException e) {
+      // Expected.
+    }
+  }
+}