content: /*
   * 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.
   */
  
  /*
   * Based on LimitedInputStream.java from Google Guava
   *
   * Copyright (C) 2007 The Guava 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 org.apache.spark.network.util;
  
  import java.io.FilterInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  import com.google.common.base.Preconditions;
  
  /**
   * Wraps a {@link InputStream}, limiting the number of bytes which can be read.
   *
   * This code is from Guava's 14.0 source code, because there is no compatible way to
   * use this functionality in both a Guava 11 environment and a Guava &gt;14 environment.
   */
  public final class LimitedInputStream extends FilterInputStream {
    private final boolean closeWrappedStream;
    private long left;
    private long mark = -1;
  
    public LimitedInputStream(InputStream in, long limit) {
      this(in, limit, true);
    }
  
    /**
     * Create a LimitedInputStream that will read {@code limit} bytes from {@code in}.
     * <p>
     * If {@code closeWrappedStream} is true, this will close {@code in} when it is closed.
     * Otherwise, the stream is left open for reading its remaining content.
     *
     * @param in a {@link InputStream} to read from
     * @param limit the number of bytes to read
     * @param closeWrappedStream whether to close {@code in} when {@link #close} is called
       */
    public LimitedInputStream(InputStream in, long limit, boolean closeWrappedStream) {
      super(in);
      this.closeWrappedStream = closeWrappedStream;
      Preconditions.checkNotNull(in);
      Preconditions.checkArgument(limit >= 0, "limit must be non-negative");
      left = limit;
    }
    @Override public int available() throws IOException {
      return (int) Math.min(in.available(), left);
    }
    // it's okay to mark even if mark isn't supported, as reset won't work
    @Override public synchronized void mark(int readLimit) {
      in.mark(readLimit);
      mark = left;
    }
    @Override public int read() throws IOException {
      if (left == 0) {
        return -1;
      }
      int result = in.read();
      if (result != -1) {
        --left;
      }
      return result;
    }
    @Override public int read(byte[] b, int off, int len) throws IOException {
      if (left == 0) {
        return -1;
      }
      len = (int) Math.min(len, left);
      int result = in.read(b, off, len);
      if (result != -1) {
        left -= result;
      }
      return result;
    }
    @Override public synchronized void reset() throws IOException {
      if (!in.markSupported()) {
        throw new IOException("Mark not supported");
      }
      if (mark == -1) {
        throw new IOException("Mark not set");
      }
      in.reset();
      left = mark;
    }
    @Override public long skip(long n) throws IOException {
      n = Math.min(n, left);
      long skipped = in.skip(n);
      left -= skipped;
      return skipped;
    }
  
    @Override
    public void close() throws IOException {
      if (closeWrappedStream) {
        super.close();
      }
    }
  }
  