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
  35 import com.google.common.base.Preconditions;
  36 import com.google.common.collect.ImmutableList;
  37 import com.google.common.collect.Iterables;
  38 import com.google.common.io.ByteStreams;
  39
  40 /**
  41  * {@link Filter} implementation that runs its {@link Source} through an
  42  * external program.
  43  *
  44  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  45  */
  46 public abstract class ExternalFilter implements Filter {
  47
  48         /** The logger. */
  49         private static final Logger logger = Logger.getLogger(ExternalFilter.class.getName());
  50
  51         /** The binary to execute. */
  52         private final String binary;
  53
  54         /** The parameters for the binary. */
  55         private final Iterable<String> parameters;
  56
  57         /** The format of the source. */
  58         private Format format;
  59
  60         /** The input stream that will hold the converted source. */
  61         private PipedInputStream pipedInputStream;
  62
  63         /**
  64          * Creates a new external filter.
  65          *
  66          * @param binary
  67          *              The binary to execute
  68          * @param parameters
  69          *              The parameter for the binary
  70          */
  71         public ExternalFilter(String binary, Iterable<String> parameters) {
  72                 this.binary = binary;
  73                 this.parameters = parameters;
  74         }
  75
  76         //
  77         // FILTER METHODS
  78
  79         @Override
  80         public Format format() {
  81                 return format;
  82         }
  83
  84         @Override
  85         public byte[] get(int bufferSize) throws EOFException, IOException {
  86                 byte[] buffer = new byte[bufferSize];
  87                 int read = pipedInputStream.read(buffer);
  88                 return Arrays.copyOf(buffer, read);
  89         }
  90
  91         @Override
  92         public void connect(Source source) throws ConnectException {
  93                 Preconditions.checkNotNull(source, "source must not be null");
  94
  95                 format = source.format();
  96                 try {
  97                         Process process = Runtime.getRuntime().exec(Iterables.toArray(ImmutableList.<String>builder().add(binary).addAll(parameters).build(), String.class));
  98                         final InputStream processOutput = process.getInputStream();
  99                         final OutputStream processInput = process.getOutputStream();
 100                         final InputStream processError = process.getErrorStream();
 101                         final PipedOutputStream pipedOutputStream = new PipedOutputStream();
 102                         pipedInputStream = new PipedInputStream(pipedOutputStream);
 103                         new Thread(new Runnable() {
 104
 105                                 @Override
 106                                 public void run() {
 107                                         try {
 108                                                 drainInputStream(processError);
 109                                         } catch (IOException ioe1) {
 110                                                 /* ignore, just let the thread exit. */
 111                                         }
 112                                         logger.finest("ExternalFilter: Reading stderr finished.");
 113                                 }
 114                         }).start();
 115                         new Thread(new Runnable() {
 116
 117                                 @Override
 118                                 public void run() {
 119                                         try {
 120                                                 ByteStreams.copy(processOutput, pipedOutputStream);
 121                                         } catch (IOException ioe1) {
 122                                                 /* okay, just exit. */
 123                                         }
 124                                         logger.finest("ExternalFilter: Reading stdout finished.");
 125                                 }
 126                         }).start();
 127                         new Thread(new Connection(source) {
 128
 129                                 @Override
 130                                 protected int bufferSize() {
 131                                         return 4096;
 132                                 }
 133
 134                                 @Override
 135                                 protected void feed(byte[] buffer) throws IOException {
 136                                         processInput.write(buffer);
 137                                 }
 138                         }).start();
 139                 } catch (IOException ioe1) {
 140
 141                 }
 142         }
 143
 144         //
 145         // STATIC METHODS
 146         //
 147
 148         private static void drainInputStream(InputStream inputStream) throws IOException {
 149                 byte[] buffer = new byte[4096];
 150                 int read;
 151                 while ((read = inputStream.read(buffer)) != -1) {
 152                         logger.finest(String.format("ExternalFilter: Drained %d Bytes.", read));
 153                         /* do nothing, just read the damn thing. */
 154                 }
 155         }
 156
 157 }