TufGsonSupplier.java

/*
 * Copyright 2026 The Sigstore Authors.
 *
 * 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 dev.sigstore.tuf.json;

import com.google.gson.GsonBuilder;
import com.google.gson.JsonDeserializer;
import dev.sigstore.forbidden.SuppressForbidden;
import dev.sigstore.json.GsonByteArrayAdapter;
import dev.sigstore.json.GsonChecked;
import dev.sigstore.tuf.model.*;
import java.time.LocalDateTime;
import java.time.ZonedDateTime;
import java.util.function.Supplier;

/** Supplies a Gson with custom byte to base64 serialization, configured for TUF models. */
@SuppressForbidden(reason = "GsonBuilder")
public enum TufGsonSupplier implements Supplier<GsonChecked> {
  TUF_GSON;

  @SuppressWarnings("ImmutableEnumChecker")
  private final GsonChecked gson =
      new GsonChecked(
          new GsonBuilder()
              .registerTypeAdapter(byte[].class, new GsonByteArrayAdapter())
              .registerTypeAdapter(
                  LocalDateTime.class,
                  (JsonDeserializer<LocalDateTime>)
                      (json, type, jsonDeserializationContext) ->
                          ZonedDateTime.parse(json.getAsJsonPrimitive().getAsString())
                              .toLocalDateTime())
              // Immutables generated GSON Adapters in alphabetical order
              .registerTypeAdapterFactory(new GsonAdaptersDelegations())
              .registerTypeAdapterFactory(new GsonAdaptersDelegationRole())
              .registerTypeAdapterFactory(new GsonAdaptersHashes())
              .registerTypeAdapterFactory(new GsonAdaptersKey())
              .registerTypeAdapterFactory(new GsonAdaptersRoot())
              .registerTypeAdapterFactory(new GsonAdaptersRootMeta())
              .registerTypeAdapterFactory(new GsonAdaptersRootRole())
              .registerTypeAdapterFactory(new GsonAdaptersSignature())
              .registerTypeAdapterFactory(new GsonAdaptersSnapshot())
              .registerTypeAdapterFactory(new GsonAdaptersSnapshotMeta())
              .registerTypeAdapterFactory(new GsonAdaptersTargets())
              .registerTypeAdapterFactory(new GsonAdaptersTargetMeta())
              .registerTypeAdapterFactory(new GsonAdaptersTimestamp())
              .registerTypeAdapterFactory(new GsonAdaptersTimestampMeta())
              .disableHtmlEscaping()
              .create());

  @Override
  public GsonChecked get() {
    return gson;
  }
}