LogOutputStream.java

/*
 * 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.zeppelin.interpreter.util;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 * Minor modification of LogOutputStream of apache commons exec.
 * LogOutputStream of apache commons exec has one issue that method flush doesn't throw IOException,
 * so that SparkOutputStream can not extend it correctly.
 */
public abstract class LogOutputStream extends OutputStream {
  private static final int INTIAL_SIZE = 132;
  private static final int CR = 13;
  private static final int LF = 10;
  private final ByteArrayOutputStream buffer;
  private boolean skip;
  private final int level;

  public LogOutputStream() {
    this(999);
  }

  public LogOutputStream(int level) {
    this.buffer = new ByteArrayOutputStream(132);
    this.skip = false;
    this.level = level;
  }

  @Override
  public void write(int cc) throws IOException {
    byte c = (byte) cc;
    if (c != 10 && c != 13) {
      this.buffer.write(cc);
    } else if (!this.skip) {
      this.processBuffer();
    }

    this.skip = c == 13;
  }

  @Override
  public void flush() throws IOException {
    if (this.buffer.size() > 0) {
      this.processBuffer();
    }

  }

  @Override
  public void close() throws IOException {
    if (this.buffer.size() > 0) {
      this.processBuffer();
    }

    super.close();
  }

  public int getMessageLevel() {
    return this.level;
  }

  @Override
  public void write(byte[] b, int off, int len) throws IOException {
    int offset = off;
    int blockStartOffset = off;

    for (int remaining = len; remaining > 0; blockStartOffset = offset) {
      while (remaining > 0 && b[offset] != 10 && b[offset] != 13) {
        ++offset;
        --remaining;
      }

      int blockLength = offset - blockStartOffset;
      if (blockLength > 0) {
        this.buffer.write(b, blockStartOffset, blockLength);
      }

      while (remaining > 0 && (b[offset] == 10 || b[offset] == 13)) {
        this.write(b[offset]);
        ++offset;
        --remaining;
      }
    }

  }

  protected void processBuffer() {
    this.processLine(this.buffer.toString());
    this.buffer.reset();
  }

  protected void processLine(String line) {
    this.processLine(line, this.level);
  }

  protected abstract void processLine(String var1, int var2);
}