Enhance FS.runProcess() to support stdin-redirection and binary data

In order to support filters in gitattributes FS.runProcess() is made
public. Support for stdin redirection has been added. Support for binary
data on stdin/stdout (as used be clean/smudge filters) has been added.

Change-Id: Ice2c152e9391368dc5748d7b825a838e3eb755f9
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

1 files changed, 71 insertions, 40 deletions

diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
index 4e4371e8db..bcaf62a0c4 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/FS.java
@@ -44,15 +44,13 @@
 package org.eclipse.jgit.util;
 
 import java.io.BufferedReader;
-import java.io.BufferedWriter;
+import java.io.ByteArrayInputStream;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.OutputStream;
-import java.io.OutputStreamWriter;
 import java.io.PrintStream;
-import java.io.PrintWriter;
 import java.nio.charset.Charset;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
@@ -864,52 +862,88 @@ public abstract class FS {
 	 * Runs the given process until termination, clearing its stdout and stderr
 	 * streams on-the-fly.
 	 *
-	 * @param hookProcessBuilder
-	 *            The process builder configured for this hook.
+	 * @param processBuilder
+	 *            The process builder configured for this process.
 	 * @param outRedirect
-	 *            A print stream on which to redirect the hook's stdout. Can be
-	 *            <code>null</code>, in which case the hook's standard output
-	 *            will be lost.
+	 *            A OutputStream on which to redirect the processes stdout. Can
+	 *            be <code>null</code>, in which case the processes standard
+	 *            output will be lost.
 	 * @param errRedirect
-	 *            A print stream on which to redirect the hook's stderr. Can be
-	 *            <code>null</code>, in which case the hook's standard error
-	 *            will be lost.
+	 *            A OutputStream on which to redirect the processes stderr. Can
+	 *            be <code>null</code>, in which case the processes standard
+	 *            error will be lost.
 	 * @param stdinArgs
 	 *            A string to pass on to the standard input of the hook. Can be
 	 *            <code>null</code>.
-	 * @return the exit value of this hook.
+	 * @return the exit value of this process.
 	 * @throws IOException
-	 *             if an I/O error occurs while executing this hook.
+	 *             if an I/O error occurs while executing this process.
 	 * @throws InterruptedException
 	 *             if the current thread is interrupted while waiting for the
 	 *             process to end.
-	 * @since 3.7
+	 * @since 4.2
 	 */
-	protected int runProcess(ProcessBuilder hookProcessBuilder,
+	public int runProcess(ProcessBuilder processBuilder,
 			OutputStream outRedirect, OutputStream errRedirect, String stdinArgs)
 			throws IOException, InterruptedException {
+		InputStream in = (stdinArgs == null) ? null : new ByteArrayInputStream(
+				stdinArgs.getBytes(Constants.CHARACTER_ENCODING));
+		return runProcess(processBuilder, outRedirect, errRedirect, in);
+	}
+
+	/**
+	 * Runs the given process until termination, clearing its stdout and stderr
+	 * streams on-the-fly.
+	 *
+	 * @param processBuilder
+	 *            The process builder configured for this process.
+	 * @param outRedirect
+	 *            An OutputStream on which to redirect the processes stdout. Can
+	 *            be <code>null</code>, in which case the processes standard
+	 *            output will be lost. If binary is set to <code>false</code>
+	 *            then it is expected that the process emits text data which
+	 *            should be processed line by line.
+	 * @param errRedirect
+	 *            An OutputStream on which to redirect the processes stderr. Can
+	 *            be <code>null</code>, in which case the processes standard
+	 *            error will be lost.
+	 * @param inRedirect
+	 *            An InputStream from which to redirect the processes stdin. Can
+	 *            be <code>null</code>, in which case the process doesn't get
+	 *            any data over stdin. If binary is set to
+	 *            <code>false</code> then it is expected that the process
+	 *            expects text data which should be processed line by line.
+	 * @return the return code of this process.
+	 * @throws IOException
+	 *             if an I/O error occurs while executing this process.
+	 * @throws InterruptedException
+	 *             if the current thread is interrupted while waiting for the
+	 *             process to end.
+	 * @since 4.2
+	 */
+	public int runProcess(ProcessBuilder processBuilder,
+			OutputStream outRedirect, OutputStream errRedirect,
+			InputStream inRedirect) throws IOException,
+			InterruptedException {
 		final ExecutorService executor = Executors.newFixedThreadPool(2);
 		Process process = null;
 		// We'll record the first I/O exception that occurs, but keep on trying
 		// to dispose of our open streams and file handles
 		IOException ioException = null;
 		try {
-			process = hookProcessBuilder.start();
+			process = processBuilder.start();
 			final Callable<Void> errorGobbler = new StreamGobbler(
 					process.getErrorStream(), errRedirect);
 			final Callable<Void> outputGobbler = new StreamGobbler(
 					process.getInputStream(), outRedirect);
 			executor.submit(errorGobbler);
 			executor.submit(outputGobbler);
-			if (stdinArgs != null) {
-				final PrintWriter stdinWriter = new PrintWriter(
-						process.getOutputStream());
-				stdinWriter.print(stdinArgs);
-				stdinWriter.flush();
-				// We are done with this hook's input. Explicitly close its
-				// stdin now to kick off any blocking read the hook might have.
-				stdinWriter.close();
+			OutputStream outputStream = process.getOutputStream();
+			if (inRedirect != null) {
+				new StreamGobbler(inRedirect, outputStream)
+						.call();
 			}
+			outputStream.close();
 			return process.waitFor();
 		} catch (IOException e) {
 			ioException = e;
@@ -1187,30 +1221,27 @@ public abstract class FS {
 	 * </p>
 	 */
 	private static class StreamGobbler implements Callable<Void> {
-		private final BufferedReader reader;
+		private InputStream in;
 
-		private final BufferedWriter writer;
+		private OutputStream out;
 
 		public StreamGobbler(InputStream stream, OutputStream output) {
-			this.reader = new BufferedReader(new InputStreamReader(stream));
-			if (output == null)
-				this.writer = null;
-			else
-				this.writer = new BufferedWriter(new OutputStreamWriter(output));
+			this.in = stream;
+			this.out = output;
 		}
 
 		public Void call() throws IOException {
 			boolean writeFailure = false;
-
-			String line = null;
-			while ((line = reader.readLine()) != null) {
-				// Do not try to write again after a failure, but keep reading
-				// as long as possible to prevent the input stream from choking.
-				if (!writeFailure && writer != null) {
+			byte buffer[] = new byte[4096];
+			int readBytes;
+			while ((readBytes = in.read(buffer)) != -1) {
+				// Do not try to write again after a failure, but keep
+				// reading as long as possible to prevent the input stream
+				// from choking.
+				if (!writeFailure && out != null) {
 					try {
-						writer.write(line);
-						writer.newLine();
-						writer.flush();
+						out.write(buffer, 0, readBytes);
+						out.flush();
 					} catch (IOException e) {
 						writeFailure = true;
 					}