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.Metadata;
  34 import net.pterodactylus.sonitus.data.Source;
  35 import net.pterodactylus.sonitus.io.InputStreamDrainer;
  36
  37 import com.google.common.base.Preconditions;
  38 import com.google.common.collect.ImmutableList;
  39 import com.google.common.collect.Iterables;
  40 import com.google.common.io.ByteStreams;
  41
  42 /**
  43  * {@link Filter} implementation that runs its {@link Source} through an
  44  * external program.
  45  *
  46  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  47  */
  48 public abstract class ExternalFilter implements Filter {
  49
  50         /** The logger. */
  51         private final Logger logger = Logger.getLogger(getClass().getName());
  52
  53         /** The source. */
  54         private Source source;
  55
  56         /** The input stream that will hold the converted source. */
  57         private PipedInputStream pipedInputStream;
  58
  59         //
  60         // FILTER METHODS
  61         //
  62
  63         @Override
  64         public Format format() {
  65                 return source.format();
  66         }
  67
  68         @Override
  69         public Metadata metadata() {
  70                 return source.metadata();
  71         }
  72
  73         @Override
  74         public byte[] get(int bufferSize) throws EOFException, IOException {
  75                 byte[] buffer = new byte[bufferSize];
  76                 int read = pipedInputStream.read(buffer);
  77                 if (read == -1) {
  78                         throw new EOFException();
  79                 }
  80                 return Arrays.copyOf(buffer, read);
  81         }
  82
  83         @Override
  84         public void connect(Source source) throws ConnectException {
  85                 Preconditions.checkNotNull(source, "source must not be null");
  86
  87                 this.source = source;
  88                 try {
  89                         final Process process = Runtime.getRuntime().exec(Iterables.toArray(ImmutableList.<String>builder().add(binary(source.format())).addAll(parameters(source.format())).build(), String.class));
  90                         final InputStream processOutput = process.getInputStream();
  91                         final OutputStream processInput = process.getOutputStream();
  92                         final InputStream processError = process.getErrorStream();
  93                         final PipedOutputStream pipedOutputStream = new PipedOutputStream();
  94                         pipedInputStream = new PipedInputStream(pipedOutputStream);
  95                         new Thread(new InputStreamDrainer(processError)).start();
  96                         new Thread(new Runnable() {
  97
  98                                 @Override
  99                                 public void run() {
 100                                         try {
 101                                                 ByteStreams.copy(processOutput, pipedOutputStream);
 102                                         } catch (IOException ioe1) {
 103                                                 /* okay, just exit. */
 104                                         }
 105                                         logger.finest("Reading stdout finished.");
 106                                 }
 107                         }).start();
 108                         new Thread(new Connection(source) {
 109
 110                                 @Override
 111                                 protected int bufferSize() {
 112                                         return 4096;
 113                                 }
 114
 115                                 @Override
 116                                 protected void feed(byte[] buffer) throws IOException {
 117                                         processInput.write(buffer);
 118                                         processInput.flush();
 119                                 }
 120
 121                                 @Override
 122                                 protected void finish() throws IOException {
 123                                         processInput.close();
 124                                         processOutput.close();
 125                                         processError.close();
 126                                 }
 127                         }).start();
 128                 } catch (IOException ioe1) {
 129
 130                 }
 131         }
 132
 133         @Override
 134         public void metadataUpdated() {
 135                 /* ignore. */
 136         }
 137
 138         //
 139         // SUBCLASS METHODS
 140         //
 141
 142         /**
 143          * Returns the location of the binary to execute.
 144          *
 145          * @param format
 146          *              The format being processed
 147          * @return The location of the binary to execute
 148          */
 149         protected abstract String binary(Format format);
 150
 151         /**
 152          * Returns the parameters for the binary.
 153          *
 154          * @param format
 155          *              The format being processed
 156          * @return The parameters for the binary
 157          */
 158         protected abstract Iterable<String> parameters(Format format);
 159
 160 }