/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements. See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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 org.apache.logging.log4j.core.layout;
  
  import org.apache.logging.log4j.core.util.Constants;
  import org.apache.logging.log4j.status.StatusLogger;
  
  import java.nio.CharBuffer;
  import java.nio.charset.Charset;
  import java.nio.charset.CharsetEncoder;
  import java.nio.charset.CodingErrorAction;
  import java.util.Objects;
  
  /**
   * Encoder for StringBuilders that locks on the ByteBufferDestination.
   */
  public class LockingStringBuilderEncoder implements Encoder<StringBuilder> {
  
      private final Charset charset;
      private final CharsetEncoder charsetEncoder;
      private final CharBuffer cachedCharBuffer;
  
      public LockingStringBuilderEncoder(final Charset charset) {
          this(charset, Constants.ENCODER_CHAR_BUFFER_SIZE);
      }
  
      public LockingStringBuilderEncoder(final Charset charset, final int charBufferSize) {
          this.charset = Objects.requireNonNull(charset, "charset");
          this.charsetEncoder = charset.newEncoder().onMalformedInput(CodingErrorAction.REPLACE)
                  .onUnmappableCharacter(CodingErrorAction.REPLACE);
          this.cachedCharBuffer = CharBuffer.wrap(new char[charBufferSize]);
      }
  
      private CharBuffer getCharBuffer() {
          return cachedCharBuffer;
      }
  
      @Override
      public void encode(final StringBuilder source, final ByteBufferDestination destination) {
          try {
              // This synchronized is needed to be able to call destination.getByteBuffer()
              synchronized (destination) {
                  TextEncoderHelper.encodeText(charsetEncoder, cachedCharBuffer, destination.getByteBuffer(), source,
                      destination);
              }
          } catch (final Exception ex) {
              logEncodeTextException(ex, source, destination);
              TextEncoderHelper.encodeTextFallBack(charset, source, destination);
          }
  
      }
  
      private void logEncodeTextException(final Exception ex, final StringBuilder text,
                                          final ByteBufferDestination destination) {
          StatusLogger.getLogger().error("Recovering from LockingStringBuilderEncoder.encode('{}') error", text, ex);
      }
  }