content: /*
   * Copyright 1999-2020 Alibaba Group Holding Ltd.
   *
   * 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.alibaba.nacos.naming.core.v2.metadata;
  
  import com.alibaba.nacos.consistency.snapshot.LocalFileMeta;
  import com.alibaba.nacos.consistency.snapshot.Reader;
  import com.alibaba.nacos.consistency.snapshot.Writer;
  import com.alibaba.nacos.naming.consistency.persistent.impl.AbstractSnapshotOperation;
  import com.alibaba.nacos.sys.utils.DiskUtils;
  import com.alipay.sofa.jraft.util.CRC64;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.nio.file.Paths;
  import java.util.Objects;
  import java.util.concurrent.locks.ReentrantReadWriteLock;
  import java.util.zip.Checksum;
  
  /**
   * Nacos naming snapshot operation for metadata.
   *
   * @author xiweng.yy
   */
  public abstract class AbstractMetadataSnapshotOperation extends AbstractSnapshotOperation {
      
      private static final String METADATA_CHILD_NAME = "metadata";
      
      public AbstractMetadataSnapshotOperation(ReentrantReadWriteLock lock) {
          super(lock);
      }
      
      @Override
      protected boolean writeSnapshot(Writer writer) throws IOException {
          final String writePath = writer.getPath();
          final String outputFile = Paths.get(writePath, getSnapshotArchive()).toString();
          final Checksum checksum = new CRC64();
          try (InputStream inputStream = dumpSnapshot()) {
              DiskUtils.compressIntoZipFile(METADATA_CHILD_NAME, inputStream, outputFile, checksum);
          }
          final LocalFileMeta meta = new LocalFileMeta();
          meta.append(CHECK_SUM_KEY, Long.toHexString(checksum.getValue()));
          return writer.addFile(getSnapshotArchive(), meta);
      }
      
      @Override
      protected boolean readSnapshot(Reader reader) throws Exception {
          final String readerPath = reader.getPath();
          final String sourceFile = Paths.get(readerPath, getSnapshotArchive()).toString();
          final Checksum checksum = new CRC64();
          byte[] snapshotBytes = DiskUtils.decompress(sourceFile, checksum);
          LocalFileMeta fileMeta = reader.getFileMeta(getSnapshotArchive());
          if (fileMeta.getFileMeta().containsKey(CHECK_SUM_KEY)) {
              if (!Objects.equals(Long.toHexString(checksum.getValue()), fileMeta.get(CHECK_SUM_KEY))) {
                  throw new IllegalArgumentException("Snapshot checksum failed");
              }
          }
          loadSnapshot(snapshotBytes);
          return true;
      }
      
      /**
       * Get snapshot archive file name.
       *
       * @return snapshot archive
       */
      protected abstract String getSnapshotArchive();
      
      /**
       * Dump snapshot as input stream.
       *
       * @return snapshot
       */
      protected abstract InputStream dumpSnapshot();
      
      /**
       * Load snapshot.
       *
       * @param snapshotBytes snapshot bytes
       */
      protected abstract void loadSnapshot(byte[] snapshotBytes);
  }
  