src/main/java/net/pterodactylus/sonitus/data/filter/ExternalFilter.java

   1 /*
   2  * Sonitus - ExternalFilter.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sonitus.data.filter;
  19
  20 import java.io.EOFException;
  21 import java.io.IOException;
  22 import java.io.InputStream;
  23 import java.io.OutputStream;
  24 import java.io.PipedInputStream;
  25 import java.io.PipedOutputStream;
  26 import java.util.Arrays;
  27 import java.util.logging.Logger;
  28
  29 import net.pterodactylus.sonitus.data.ConnectException;
  30 import net.pterodactylus.sonitus.data.Connection;
  31 import net.pterodactylus.sonitus.data.Filter;
  32 import net.pterodactylus.sonitus.data.Format;
  33 import net.pterodactylus.sonitus.data.Source;
  34 import net.pterodactylus.sonitus.io.InputStreamDrainer;
  35
  36 import com.google.common.base.Preconditions;
  37 import com.google.common.collect.ImmutableList;
  38 import com.google.common.collect.Iterables;
  39 import com.google.common.io.ByteStreams;
  40
  41 /**
  42  * {@link Filter} implementation that runs its {@link Source} through an
  43  * external program.
  44  *
  45  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  46  */
  47 public abstract class ExternalFilter implements Filter {
  48
  49         /** The logger. */
  50         private final Logger logger = Logger.getLogger(getClass().getName());
  51
  52         /** The format of the source. */
  53         private Format format;
  54
  55         /** The input stream that will hold the converted source. */
  56         private PipedInputStream pipedInputStream;
  57
  58         //
  59         // FILTER METHODS
  60
  61         @Override
  62         public Format format() {
  63                 return format;
  64         }
  65
  66         @Override
  67         public byte[] get(int bufferSize) throws EOFException, IOException {
  68                 byte[] buffer = new byte[bufferSize];
  69                 int read = pipedInputStream.read(buffer);
  70                 if (read == -1) {
  71                         throw new EOFException();
  72                 }
  73                 return Arrays.copyOf(buffer, read);
  74         }
  75
  76         @Override
  77         public void connect(Source source) throws ConnectException {
  78                 Preconditions.checkNotNull(source, "source must not be null");
  79
  80                 format = source.format();
  81                 try {
  82                         final Process process = Runtime.getRuntime().exec(Iterables.toArray(ImmutableList.<String>builder().add(binary(format)).addAll(parameters(format)).build(), String.class));
  83                         final InputStream processOutput = process.getInputStream();
  84                         final OutputStream processInput = process.getOutputStream();
  85                         final InputStream processError = process.getErrorStream();
  86                         final PipedOutputStream pipedOutputStream = new PipedOutputStream();
  87                         pipedInputStream = new PipedInputStream(pipedOutputStream);
  88                         new Thread(new InputStreamDrainer(processError)).start();
  89                         new Thread(new Runnable() {
  90
  91                                 @Override
  92                                 public void run() {
  93                                         try {
  94                                                 ByteStreams.copy(processOutput, pipedOutputStream);
  95                                         } catch (IOException ioe1) {
  96                                                 /* okay, just exit. */
  97                                         }
  98                                         logger.finest("Reading stdout finished.");
  99                                 }
 100                         }).start();
 101                         new Thread(new Connection(source) {
 102
 103                                 @Override
 104                                 protected int bufferSize() {
 105                                         return 4096;
 106                                 }
 107
 108                                 @Override
 109                                 protected void feed(byte[] buffer) throws IOException {
 110                                         processInput.write(buffer);
 111                                         processInput.flush();
 112                                 }
 113
 114                                 @Override
 115                                 protected void finish() throws IOException {
 116                                         processInput.close();
 117                                         processOutput.close();
 118                                         processError.close();
 119                                 }
 120                         }).start();
 121                 } catch (IOException ioe1) {
 122
 123                 }
 124         }
 125
 126         //
 127         // SUBCLASS METHODS
 128         //
 129
 130         /**
 131          * Returns the location of the binary to execute.
 132          *
 133          * @param format
 134          *              The format being processed
 135          * @return The location of the binary to execute
 136          */
 137         protected abstract String binary(Format format);
 138
 139         /**
 140          * Returns the parameters for the binary.
 141          *
 142          * @param format
 143          *              The format being processed
 144          * @return The parameters for the binary
 145          */
 146         protected abstract Iterable<String> parameters(Format format);
 147
 148 }