text: /*
   This file is part of Subsonic.
  
   Subsonic is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
  
   Subsonic is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
  
   You should have received a copy of the GNU General Public License
   along with Subsonic.  If not, see <http://www.gnu.org/licenses/>.
  
   Copyright 2009 (C) Sindre Mehus
   */
  package net.sourceforge.subsonic.io;
  
  import net.sourceforge.subsonic.*;
  
  import org.apache.commons.io.*;
  
  import java.io.*;
  
  /**
   * Subclass of {@link InputStream} which provides on-the-fly transcoding.
   * Instances of <code>TranscodeInputStream</code> can be chained together, for instance to convert
   * from OGG to WAV to MP3.
   *
   * @author Sindre Mehus
   */
  public class TranscodeInputStream extends InputStream {
  
      private static final Logger LOG = Logger.getLogger(TranscodeInputStream.class);
  
      private InputStream processInputStream;
      private OutputStream processOutputStream;
      private Process process;
      private final File tmpFile;
  
      /**
       * Creates a transcoded input stream by executing an external process. If <code>in</code> is not null,
       * data from it is copied to the command.
       *
       * @param processBuilder Used to create the external process.
       * @param in Data to feed to the process.  May be {@code null}.
       * @param tmpFile Temporary file to delete when this stream is closed.  May be {@code null}.
       * @throws IOException If an I/O error occurs.
       */
      public TranscodeInputStream(ProcessBuilder processBuilder, final InputStream in, File tmpFile) throws IOException {
          this.tmpFile = tmpFile;
  
          StringBuffer buf = new StringBuffer("Starting transcoder: ");
          for (String s : processBuilder.command()) {
              buf.append('[').append(s).append("] ");
          }
          LOG.debug(buf);
  
          process = processBuilder.start();
          processOutputStream = process.getOutputStream();
          processInputStream = process.getInputStream();
  
          // Must read stderr from the process, otherwise it may block.
          final String name = processBuilder.command().get(0);
          new InputStreamReaderThread(process.getErrorStream(), name, true).start();
  
          // Copy data in a separate thread
          if (in != null) {
              new Thread(name + " TranscodedInputStream copy thread") {
                  public void run() {
                      try {
                          IOUtils.copy(in, processOutputStream);
                      } catch (IOException x) {
                          // Intentionally ignored. Will happen if the remote player closes the stream.
                      } finally {
                          IOUtils.closeQuietly(in);
                          IOUtils.closeQuietly(processOutputStream);
                      }
                  }
              }.start();
          }
      }
  
      /**
       * @see InputStream#read()
       */
      public int read() throws IOException {
          return processInputStream.read();
      }
  
      /**
       * @see InputStream#read(byte[])
       */
      public int read(byte[] b) throws IOException {
          return processInputStream.read(b);
      }
  
      /**
       * @see InputStream#read(byte[], int, int)
       */
      public int read(byte[] b, int off, int len) throws IOException {
          return processInputStream.read(b, off, len);
      }
  
      /**
       * @see InputStream#close()
       */
      public void close() throws IOException {
          IOUtils.closeQuietly(processInputStream);
          IOUtils.closeQuietly(processOutputStream);
  
          if (process != null) {
              process.destroy();
          }
  
          if (tmpFile != null) {
              if (!tmpFile.delete()) {
                  LOG.warn("Failed to delete tmp file: " + tmpFile);
              }
          }
      }
  }
  