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 final Logger logger = Logger.getLogger(getClass().getName());
  50
  51         /** The format of the source. */
  52         private Format format;
  53
  54         /** The input stream that will hold the converted source. */
  55         private PipedInputStream pipedInputStream;
  56
  57         //
  58         // FILTER METHODS
  59
  60         @Override
  61         public Format format() {
  62                 return format;
  63         }
  64
  65         @Override
  66         public byte[] get(int bufferSize) throws EOFException, IOException {
  67                 byte[] buffer = new byte[bufferSize];
  68                 int read = pipedInputStream.read(buffer);
  69                 return Arrays.copyOf(buffer, read);
  70         }
  71
  72         @Override
  73         public void connect(Source source) throws ConnectException {
  74                 Preconditions.checkNotNull(source, "source must not be null");
  75
  76                 format = source.format();
  77                 try {
  78                         final Process process = Runtime.getRuntime().exec(Iterables.toArray(ImmutableList.<String>builder().add(binary(format)).addAll(parameters(format)).build(), String.class));
  79                         final InputStream processOutput = process.getInputStream();
  80                         final OutputStream processInput = process.getOutputStream();
  81                         final InputStream processError = process.getErrorStream();
  82                         final PipedOutputStream pipedOutputStream = new PipedOutputStream();
  83                         pipedInputStream = new PipedInputStream(pipedOutputStream);
  84                         new Thread(new Runnable() {
  85
  86                                 @Override
  87                                 public void run() {
  88                                         try {
  89                                                 drainInputStream(processError);
  90                                         } catch (IOException ioe1) {
  91                                                 /* ignore, just let the thread exit. */
  92                                         }
  93                                         logger.finest("ExternalFilter: Reading stderr finished.");
  94                                 }
  95                         }).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("ExternalFilter: 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         //
 134         // SUBCLASS METHODS
 135         //
 136
 137         /**
 138          * Returns the location of the binary to execute.
 139          *
 140          * @param format
 141          *              The format being processed
 142          * @return The location of the binary to execute
 143          */
 144         protected abstract String binary(Format format);
 145
 146         /**
 147          * Returns the parameters for the binary.
 148          *
 149          * @param format
 150          *              The format being processed
 151          * @return The parameters for the binary
 152          */
 153         protected abstract Iterable<String> parameters(Format format);
 154
 155         //
 156         // STATIC METHODS
 157         //
 158
 159         private static void drainInputStream(InputStream inputStream) throws IOException {
 160                 byte[] buffer = new byte[4096];
 161                 int read;
 162                 while ((read = inputStream.read(buffer)) != -1) {
 163                         logger.finest(String.format("ExternalFilter: Drained %d Bytes.", read));
 164                         /* do nothing, just read the damn thing. */
 165                 }
 166         }
 167
 168 }