From fcd64fc58fa16983938cfab4510e9cf555e9e1e4 Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Fri, 15 Mar 2013 23:47:17 +0100
Subject: [PATCH] Add filter that can pipe a source through an external binary.

---
 .../sonitus/data/filter/ExternalFilter.java        | 157 +++++++++++++++++++++
 1 file changed, 157 insertions(+)
 create mode 100644 src/main/java/net/pterodactylus/sonitus/data/filter/ExternalFilter.java

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
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. */
+		}
+	}
+
+}
-- 
2.7.4