Add filter that can pipe a source through an external binary.

diff --git a/src/main/java/net/pterodactylus/sonitus/data/filter/ExternalFilter.java b/src/main/java/net/pterodactylus/sonitus/data/filter/ExternalFilter.java
new file mode 100644 (file)
index 0000000..ff838d9
--- /dev/null
+++ b/src/main/java/net/pterodactylus/sonitus/data/filter/ExternalFilter.java
@@ -0,0 +1,157 @@
+/*
+ * Sonitus - ExternalFilter.java - Copyright © 2013 David Roden
+ *
+ * This program 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.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.sonitus.data.filter;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PipedInputStream;
+import java.io.PipedOutputStream;
+import java.util.Arrays;
+import java.util.logging.Logger;
+
+import net.pterodactylus.sonitus.data.ConnectException;
+import net.pterodactylus.sonitus.data.Connection;
+import net.pterodactylus.sonitus.data.Filter;
+import net.pterodactylus.sonitus.data.Format;
+import net.pterodactylus.sonitus.data.Source;
+
+import com.google.common.base.Preconditions;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.common.io.ByteStreams;
+
+/**
+ * {@link Filter} implementation that runs its {@link Source} through an
+ * external program.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public abstract class ExternalFilter implements Filter {
+
+       /** The logger. */
+       private static final Logger logger = Logger.getLogger(ExternalFilter.class.getName());
+
+       /** The binary to execute. */
+       private final String binary;
+
+       /** The parameters for the binary. */
+       private final Iterable<String> parameters;
+
+       /** The format of the source. */
+       private Format format;
+
+       /** The input stream that will hold the converted source. */
+       private PipedInputStream pipedInputStream;
+
+       /**
+        * Creates a new external filter.
+        *
+        * @param binary
+        *              The binary to execute
+        * @param parameters
+        *              The parameter for the binary
+        */
+       public ExternalFilter(String binary, Iterable<String> parameters) {
+               this.binary = binary;
+               this.parameters = parameters;
+       }
+
+       //
+       // FILTER METHODS
+
+       @Override
+       public Format format() {
+               return format;
+       }
+
+       @Override
+       public byte[] get(int bufferSize) throws EOFException, IOException {
+               byte[] buffer = new byte[bufferSize];
+               int read = pipedInputStream.read(buffer);
+               return Arrays.copyOf(buffer, read);
+       }
+
+       @Override
+       public void connect(Source source) throws ConnectException {
+               Preconditions.checkNotNull(source, "source must not be null");
+
+               format = source.format();
+               try {
+                       Process process = Runtime.getRuntime().exec(Iterables.toArray(ImmutableList.<String>builder().add(binary).addAll(parameters).build(), String.class));
+                       final InputStream processOutput = process.getInputStream();
+                       final OutputStream processInput = process.getOutputStream();
+                       final InputStream processError = process.getErrorStream();
+                       final PipedOutputStream pipedOutputStream = new PipedOutputStream();
+                       pipedInputStream = new PipedInputStream(pipedOutputStream);
+                       new Thread(new Runnable() {
+
+                               @Override
+                               public void run() {
+                                       try {
+                                               drainInputStream(processError);
+                                       } catch (IOException ioe1) {
+                                               /* ignore, just let the thread exit. */
+                                       }
+                                       logger.finest("ExternalFilter: Reading stderr finished.");
+                               }
+                       }).start();
+                       new Thread(new Runnable() {
+
+                               @Override
+                               public void run() {
+                                       try {
+                                               ByteStreams.copy(processOutput, pipedOutputStream);
+                                       } catch (IOException ioe1) {
+                                               /* okay, just exit. */
+                                       }
+                                       logger.finest("ExternalFilter: Reading stdout finished.");
+                               }
+                       }).start();
+                       new Thread(new Connection(source) {
+
+                               @Override
+                               protected int bufferSize() {
+                                       return 4096;
+                               }
+
+                               @Override
+                               protected void feed(byte[] buffer) throws IOException {
+                                       processInput.write(buffer);
+                               }
+                       }).start();
+               } catch (IOException ioe1) {
+
+               }
+       }
+
+       //
+       // STATIC METHODS
+       //
+
+       private static void drainInputStream(InputStream inputStream) throws IOException {
+               byte[] buffer = new byte[4096];
+               int read;
+               while ((read = inputStream.read(buffer)) != -1) {
+                       logger.finest(String.format("ExternalFilter: Drained %d Bytes.", read));
+                       /* do nothing, just read the damn thing. */
+               }
+       }
+
+}