8132394: (process) ProcessBuilder support for a pipeline of processes
Reviewed-by: psandoz, alanb
--- a/jdk/src/java.base/share/classes/java/lang/ProcessBuilder.java Fri Nov 13 12:00:23 2015 -0500
+++ b/jdk/src/java.base/share/classes/java/lang/ProcessBuilder.java Fri Nov 13 15:48:59 2015 -0500
@@ -26,9 +26,11 @@
package java.lang;
import java.io.File;
+import java.io.FileDescriptor;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
+import java.nio.channels.Pipe;
import java.util.Arrays;
import java.util.ArrayList;
import java.util.List;
@@ -43,6 +45,11 @@
* {@link Process} instance with those attributes. The {@link
* #start()} method can be invoked repeatedly from the same instance
* to create new subprocesses with identical or related attributes.
+ * <p>
+ * The {@link #startPipeline startPipeline} method can be invoked to create
+ * a pipeline of new processes that send the output of each process
+ * directly to the next process. Each process has the attributes of
+ * its respective ProcessBuilder.
*
* <p>Each process builder manages these process attributes:
*
@@ -696,11 +703,37 @@
private Redirect() {}
}
+ /**
+ * Private implementation subclass of Redirect that holds a FileDescriptor for the
+ * output of a previously started Process.
+ * The FileDescriptor is used as the standard input of the next Process
+ * to be started.
+ */
+ static class RedirectPipeImpl extends Redirect {
+ final FileDescriptor fd;
+
+ RedirectPipeImpl() {
+ this.fd = new FileDescriptor();
+ }
+ @Override
+ public Type type() { return Type.PIPE; }
+
+ @Override
+ public String toString() { return type().toString();}
+
+ FileDescriptor getFd() { return fd; }
+ }
+
+ /**
+ * Return the array of redirects, creating the default as needed.
+ * @return the array of redirects
+ */
private Redirect[] redirects() {
- if (redirects == null)
+ if (redirects == null) {
redirects = new Redirect[] {
- Redirect.PIPE, Redirect.PIPE, Redirect.PIPE
+ Redirect.PIPE, Redirect.PIPE, Redirect.PIPE
};
+ }
return redirects;
}
@@ -1039,6 +1072,18 @@
* @see Runtime#exec(String[], String[], java.io.File)
*/
public Process start() throws IOException {
+ return start(redirects);
+ }
+
+ /**
+ * Start a new Process using an explicit array of redirects.
+ * See {@link #start} for details of starting each Process.
+ *
+ * @param redirect array of redirects for stdin, stdout, stderr
+ * @return the new Process
+ * @throws IOException if an I/O error occurs
+ */
+ private Process start(Redirect[] redirects) throws IOException {
// Must convert to array first -- a malicious user-supplied
// list might try to circumvent the security check.
String[] cmdarray = command.toArray(new String[command.size()]);
@@ -1089,4 +1134,171 @@
cause);
}
}
+
+ /**
+ * Starts a Process for each ProcessBuilder, creating a pipeline of
+ * processes linked by their standard output and standard input streams.
+ * The attributes of each ProcessBuilder are used to start the respective
+ * process except that as each process is started, its standard output
+ * is directed to the standard input of the next. The redirects for standard
+ * input of the first process and standard output of the last process are
+ * initialized using the redirect settings of the respective ProcessBuilder.
+ * All other {@code ProcessBuilder} redirects should be
+ * {@link Redirect#PIPE Redirect.PIPE}.
+ * <p>
+ * All input and output streams between the intermediate processes are
+ * not accessible.
+ * The {@link Process#getOutputStream standard input} of all processes
+ * except the first process are <i>null output streams</i>
+ * The {@link Process#getInputStream standard output} of all processes
+ * except the last process are <i>null input streams</i>.
+ * <p>
+ * The {@link #redirectErrorStream} of each ProcessBuilder applies to the
+ * respective process. If set to {@code true}, the error stream is written
+ * to the same stream as standard output.
+ * <p>
+ * If starting any of the processes throws an Exception, all processes
+ * are forcibly destroyed.
+ * <p>
+ * The {@code startPipeline} method performs the same checks on
+ * each ProcessBuilder as does the {@link #start} method. The new process
+ * will invoke the command and arguments given by {@link #command()},
+ * in a working directory as given by {@link #directory()},
+ * with a process environment as given by {@link #environment()}.
+ * <p>
+ * This method checks that the command is a valid operating
+ * system command. Which commands are valid is system-dependent,
+ * but at the very least the command must be a non-empty list of
+ * non-null strings.
+ * <p>
+ * A minimal set of system dependent environment variables may
+ * be required to start a process on some operating systems.
+ * As a result, the subprocess may inherit additional environment variable
+ * settings beyond those in the process builder's {@link #environment()}.
+ * <p>
+ * If there is a security manager, its
+ * {@link SecurityManager#checkExec checkExec}
+ * method is called with the first component of this object's
+ * {@code command} array as its argument. This may result in
+ * a {@link SecurityException} being thrown.
+ * <p>
+ * Starting an operating system process is highly system-dependent.
+ * Among the many things that can go wrong are:
+ * <ul>
+ * <li>The operating system program file was not found.
+ * <li>Access to the program file was denied.
+ * <li>The working directory does not exist.
+ * <li>Invalid character in command argument, such as NUL.
+ * </ul>
+ * <p>
+ * In such cases an exception will be thrown. The exact nature
+ * of the exception is system-dependent, but it will always be a
+ * subclass of {@link IOException}.
+ * <p>
+ * If the operating system does not support the creation of
+ * processes, an {@link UnsupportedOperationException} will be thrown.
+ * <p>
+ * Subsequent modifications to this process builder will not
+ * affect the returned {@link Process}.
+ * @apiNote
+ * For example to count the unique imports for all the files in a file hierarchy
+ * on a Unix compatible platform:
+ * <pre>{@code
+ * String directory = "/home/duke/src";
+ * ProcessBuilder[] builders = {
+ * new ProcessBuilder("find", directory, "-type", "f"),
+ new ProcessBuilder("xargs", "grep", "-h", "^import "),
+ new ProcessBuilder("awk", "{print $2;}"),
+ new ProcessBuilder("sort", "-u")};
+ * List<Process> processes = ProcessBuilder.startPipeline(
+ * Arrays.asList(builders));
+ * Process last = processes.get(processes.size()-1);
+ * try (InputStream is = last.getInputStream();
+ * Reader isr = new InputStreamReader(is);
+ * BufferedReader r = new BufferedReader(isr)) {
+ * long count = r.lines().count();
+ * }
+ * }</pre>
+ *
+ * @param builders a List of ProcessBuilders
+ * @return a {@code List<Process>}es started from the corresponding
+ * ProcessBuilder
+ * @throws IllegalArgumentException any of the redirects except the
+ * standard input of the first builder and the standard output of
+ * the last builder are not {@link Redirect#PIPE}.
+ * @throws NullPointerException
+ * if an element of the command list is null or
+ * if an element of the ProcessBuilder list is null or
+ * the builders argument is null
+ * @throws IndexOutOfBoundsException
+ * if the command is an empty list (has size {@code 0})
+ * @throws SecurityException
+ * if a security manager exists and
+ * <ul>
+ * <li>its
+ * {@link SecurityManager#checkExec checkExec}
+ * method doesn't allow creation of the subprocess, or
+ * <li>the standard input to the subprocess was
+ * {@linkplain #redirectInput redirected from a file}
+ * and the security manager's
+ * {@link SecurityManager#checkRead(String) checkRead} method
+ * denies read access to the file, or
+ * <li>the standard output or standard error of the
+ * subprocess was
+ * {@linkplain #redirectOutput redirected to a file}
+ * and the security manager's
+ * {@link SecurityManager#checkWrite(String) checkWrite} method
+ * denies write access to the file
+ * </ul>
+ *
+ * @throws UnsupportedOperationException
+ * If the operating system does not support the creation of processes
+ *
+ * @throws IOException if an I/O error occurs
+ */
+ public static List<Process> startPipeline(List<ProcessBuilder> builders) throws IOException {
+ // Accumulate and check the builders
+ final int numBuilders = builders.size();
+ List<Process> processes = new ArrayList<>(numBuilders);
+ try {
+ Redirect prevOutput = null;
+ for (int index = 0; index < builders.size(); index++) {
+ ProcessBuilder builder = builders.get(index);
+ Redirect[] redirects = builder.redirects();
+ if (index > 0) {
+ // check the current Builder to see if it can take input from the previous
+ if (builder.redirectInput() != Redirect.PIPE) {
+ throw new IllegalArgumentException("builder redirectInput()" +
+ " must be PIPE except for the first builder: "
+ + builder.redirectInput());
+ }
+ redirects[0] = prevOutput;
+ }
+ if (index < numBuilders - 1) {
+ // check all but the last stage has output = PIPE
+ if (builder.redirectOutput() != Redirect.PIPE) {
+ throw new IllegalArgumentException("builder redirectOutput()" +
+ " must be PIPE except for the last builder: "
+ + builder.redirectOutput());
+ }
+ redirects[1] = new RedirectPipeImpl(); // placeholder for new output
+ }
+ processes.add(builder.start(redirects));
+ prevOutput = redirects[1];
+ }
+ } catch (Exception ex) {
+ // Cleanup processes already started
+ processes.forEach(Process::destroyForcibly);
+ processes.forEach(p -> {
+ try {
+ p.waitFor(); // Wait for it to exit
+ } catch (InterruptedException ie) {
+ // If interrupted; continue with next Process
+ Thread.currentThread().interrupt();
+ }
+ });
+ throw ex;
+ }
+ return processes;
+ }
}
--- a/jdk/src/java.base/unix/classes/java/lang/ProcessImpl.java Fri Nov 13 12:00:23 2015 -0500
+++ b/jdk/src/java.base/unix/classes/java/lang/ProcessImpl.java Fri Nov 13 15:48:59 2015 -0500
@@ -224,48 +224,75 @@
FileOutputStream f2 = null;
try {
+ boolean forceNullOutputStream = false;
if (redirects == null) {
std_fds = new int[] { -1, -1, -1 };
} else {
std_fds = new int[3];
- if (redirects[0] == Redirect.PIPE)
+ if (redirects[0] == Redirect.PIPE) {
std_fds[0] = -1;
- else if (redirects[0] == Redirect.INHERIT)
+ } else if (redirects[0] == Redirect.INHERIT) {
std_fds[0] = 0;
- else {
+ } else if (redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+ std_fds[0] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd());
+ } else {
f0 = new FileInputStream(redirects[0].file());
std_fds[0] = fdAccess.get(f0.getFD());
}
- if (redirects[1] == Redirect.PIPE)
+ if (redirects[1] == Redirect.PIPE) {
std_fds[1] = -1;
- else if (redirects[1] == Redirect.INHERIT)
+ } else if (redirects[1] == Redirect.INHERIT) {
std_fds[1] = 1;
- else {
+ } else if (redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+ std_fds[1] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd());
+ // Force getInputStream to return a null stream,
+ // the fd is directly assigned to the next process.
+ forceNullOutputStream = true;
+ } else {
f1 = new FileOutputStream(redirects[1].file(),
redirects[1].append());
std_fds[1] = fdAccess.get(f1.getFD());
}
- if (redirects[2] == Redirect.PIPE)
+ if (redirects[2] == Redirect.PIPE) {
std_fds[2] = -1;
- else if (redirects[2] == Redirect.INHERIT)
+ } else if (redirects[2] == Redirect.INHERIT) {
std_fds[2] = 2;
- else {
+ } else if (redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+ std_fds[2] = fdAccess.get(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd());
+ } else {
f2 = new FileOutputStream(redirects[2].file(),
redirects[2].append());
std_fds[2] = fdAccess.get(f2.getFD());
}
}
- return new ProcessImpl
+ Process p = new ProcessImpl
(toCString(cmdarray[0]),
argBlock, args.length,
envBlock, envc[0],
toCString(dir),
std_fds,
+ forceNullOutputStream,
redirectErrorStream);
+ if (redirects != null) {
+ // Copy the fd's if they are to be redirected to another process
+ if (std_fds[0] >= 0 &&
+ redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd(), std_fds[0]);
+ }
+ if (std_fds[1] >= 0 &&
+ redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd(), std_fds[1]);
+ }
+ if (std_fds[2] >= 0 &&
+ redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.set(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd(), std_fds[2]);
+ }
+ }
+ return p;
} finally {
// In theory, close() can throw IOException
// (although it is rather unlikely to happen here)
@@ -311,6 +338,7 @@
final byte[] envBlock, final int envc,
final byte[] dir,
final int[] fds,
+ final boolean forceNullOutputStream,
final boolean redirectErrorStream)
throws IOException {
@@ -326,7 +354,7 @@
try {
doPrivileged((PrivilegedExceptionAction<Void>) () -> {
- initStreams(fds);
+ initStreams(fds, forceNullOutputStream);
return null;
});
} catch (PrivilegedActionException ex) {
@@ -340,7 +368,14 @@
return fileDescriptor;
}
- void initStreams(int[] fds) throws IOException {
+ /**
+ * Initialize the streams from the file descriptors.
+ * @param fds array of stdin, stdout, stderr fds
+ * @param forceNullOutputStream true if the stdout is being directed to
+ * a subsequent process. The stdout stream should be a null output stream .
+ * @throws IOException
+ */
+ void initStreams(int[] fds, boolean forceNullOutputStream) throws IOException {
switch (platform) {
case LINUX:
case BSD:
@@ -348,7 +383,7 @@
ProcessBuilder.NullOutputStream.INSTANCE :
new ProcessPipeOutputStream(fds[0]);
- stdout = (fds[1] == -1) ?
+ stdout = (fds[1] == -1 || forceNullOutputStream) ?
ProcessBuilder.NullInputStream.INSTANCE :
new ProcessPipeInputStream(fds[1]);
--- a/jdk/src/java.base/windows/classes/java/lang/ProcessImpl.java Fri Nov 13 12:00:23 2015 -0500
+++ b/jdk/src/java.base/windows/classes/java/lang/ProcessImpl.java Fri Nov 13 15:48:59 2015 -0500
@@ -110,38 +110,63 @@
} else {
stdHandles = new long[3];
- if (redirects[0] == Redirect.PIPE)
+ if (redirects[0] == Redirect.PIPE) {
stdHandles[0] = -1L;
- else if (redirects[0] == Redirect.INHERIT)
+ } else if (redirects[0] == Redirect.INHERIT) {
stdHandles[0] = fdAccess.getHandle(FileDescriptor.in);
- else {
+ } else if (redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+ stdHandles[0] = fdAccess.getHandle(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd());
+ } else {
f0 = new FileInputStream(redirects[0].file());
stdHandles[0] = fdAccess.getHandle(f0.getFD());
}
- if (redirects[1] == Redirect.PIPE)
+ if (redirects[1] == Redirect.PIPE) {
stdHandles[1] = -1L;
- else if (redirects[1] == Redirect.INHERIT)
+ } else if (redirects[1] == Redirect.INHERIT) {
stdHandles[1] = fdAccess.getHandle(FileDescriptor.out);
- else {
+ } else if (redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+ stdHandles[1] = fdAccess.getHandle(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd());
+ } else {
f1 = newFileOutputStream(redirects[1].file(),
redirects[1].append());
stdHandles[1] = fdAccess.getHandle(f1.getFD());
}
- if (redirects[2] == Redirect.PIPE)
+ if (redirects[2] == Redirect.PIPE) {
stdHandles[2] = -1L;
- else if (redirects[2] == Redirect.INHERIT)
+ } else if (redirects[2] == Redirect.INHERIT) {
stdHandles[2] = fdAccess.getHandle(FileDescriptor.err);
- else {
+ } else if (redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+ stdHandles[2] = fdAccess.getHandle(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd());
+ } else {
f2 = newFileOutputStream(redirects[2].file(),
redirects[2].append());
stdHandles[2] = fdAccess.getHandle(f2.getFD());
}
}
- return new ProcessImpl(cmdarray, envblock, dir,
+ Process p = new ProcessImpl(cmdarray, envblock, dir,
stdHandles, redirectErrorStream);
+ if (redirects != null) {
+ // Copy the handles's if they are to be redirected to another process
+ if (stdHandles[0] >= 0
+ && redirects[0] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.setHandle(((ProcessBuilder.RedirectPipeImpl) redirects[0]).getFd(),
+ stdHandles[0]);
+ }
+ if (stdHandles[1] >= 0
+ && redirects[1] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.setHandle(((ProcessBuilder.RedirectPipeImpl) redirects[1]).getFd(),
+ stdHandles[1]);
+ }
+ if (stdHandles[2] >= 0
+ && redirects[2] instanceof ProcessBuilder.RedirectPipeImpl) {
+ fdAccess.setHandle(((ProcessBuilder.RedirectPipeImpl) redirects[2]).getFd(),
+ stdHandles[2]);
+ }
+ }
+ return p;
} finally {
// In theory, close() can throw IOException
// (although it is rather unlikely to happen here)
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/test/java/lang/ProcessBuilder/PipelineTest.java Fri Nov 13 15:48:59 2015 -0500
@@ -0,0 +1,299 @@
+/*
+ * Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.Reader;
+import java.io.Writer;
+import java.util.Arrays;
+import java.util.List;
+
+/*
+ * @test PipelineTest
+ */
+
+public class PipelineTest {
+
+ private static void realMain(String[] args) throws Throwable {
+ t1_simplePipeline();
+ t2_translatePipeline();
+ t3_redirectErrorStream();
+ t4_failStartPipeline();
+ }
+
+ /**
+ * Return a list of the varargs arguments.
+ * @param args elements to include in the list
+ * @param <T> the type of the elements
+ * @return a {@code List<T>} of the arguments
+ */
+ @SafeVarargs
+ @SuppressWarnings("varargs")
+ static <T> List<T> asList(T... args) {
+ return Arrays.asList(args);
+ }
+
+ /**
+ * T1 - simple copy between two processes
+ */
+ static void t1_simplePipeline() {
+ try {
+ String s1 = "Now is the time to check!";
+ verify(s1, s1,
+ asList(new ProcessBuilder("cat")));
+ verify(s1, s1,
+ asList(new ProcessBuilder("cat"),
+ new ProcessBuilder("cat")));
+ verify(s1, s1,
+ asList(new ProcessBuilder("cat"),
+ new ProcessBuilder("cat"),
+ new ProcessBuilder("cat")));
+ } catch (Throwable t) {
+ unexpected(t);
+ }
+ }
+
+ /**
+ * Pipeline that modifies the content.
+ */
+ static void t2_translatePipeline() {
+ try {
+ String s2 = "Now is the time to check!";
+ String r2 = s2.replace('e', 'E').replace('o', 'O');
+ verify(s2, r2,
+ asList(new ProcessBuilder("tr", "e", "E"),
+ new ProcessBuilder("tr", "o", "O")));
+ } catch (Throwable t) {
+ unexpected(t);
+ }
+ }
+
+ /**
+ * Test that redirectErrorStream sends standard error of the first process
+ * to the standard output. The standard error of the first process should be empty.
+ * The standard output of the 2nd should contain the error message including the bad file name.
+ */
+ static void t3_redirectErrorStream() {
+ try {
+ File p1err = new File("p1-test.err");
+ File p2out = new File("p2-test.out");
+
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(new ProcessBuilder("cat", "NON-EXISTENT-FILE")
+ .redirectErrorStream(true)
+ .redirectError(p1err),
+ new ProcessBuilder("cat").redirectOutput(p2out)));
+ waitForAll(processes);
+
+ check("".equals(fileContents(p1err)), "The first process standard error should be empty");
+ String p2contents = fileContents(p2out);
+ check(p2contents.contains("NON-EXISTENT-FILE"),
+ "The error from the first process should be in the output of the second: " + p2contents);
+ } catch (Throwable t) {
+ unexpected(t);
+ }
+ }
+
+ /**
+ * Test that no processes are left after a failed startPipeline.
+ * Test illegal combinations of redirects.
+ */
+ static void t4_failStartPipeline() {
+ File p1err = new File("p1-test.err");
+ File p2out = new File("p2-test.out");
+
+ THROWS(IllegalArgumentException.class,
+ () -> {
+ // Test that output redirect != PIPE throws IAE
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(new ProcessBuilder("cat", "NON-EXISTENT-FILE1")
+ .redirectOutput(p1err),
+ new ProcessBuilder("cat")));
+ },
+ () -> {
+ // Test that input redirect != PIPE throws IAE
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(new ProcessBuilder("cat", "NON-EXISTENT-FILE2"),
+ new ProcessBuilder("cat").redirectInput(p2out)));
+ }
+ );
+
+ THROWS(NullPointerException.class,
+ () -> {
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(new ProcessBuilder("cat", "a"), null));
+ },
+ () -> {
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(null, new ProcessBuilder("cat", "b")));
+ }
+ );
+
+ THROWS(IOException.class,
+ () -> {
+ List<Process> processes = ProcessBuilder.startPipeline(
+ asList(new ProcessBuilder("cat", "c"),
+ new ProcessBuilder("NON-EXISTENT-COMMAND")));
+ });
+
+ // Check no subprocess are left behind
+ ProcessHandle.current().children().forEach(PipelineTest::print);
+ ProcessHandle.current().children()
+ .filter(p -> p.info().command().orElse("").contains("cat"))
+ .forEach(p -> fail("process should have been destroyed: " + p));
+ }
+
+ static void verify(String input, String expected, List<ProcessBuilder> builders) throws IOException {
+ File infile = new File("test.in");
+ File outfile = new File("test.out");
+ setFileContents(infile, expected);
+ for (int i = 0; i < builders.size(); i++) {
+ ProcessBuilder b = builders.get(i);
+ if (i == 0) {
+ b.redirectInput(infile);
+ }
+ if (i == builders.size() - 1) {
+ b.redirectOutput(outfile);
+ }
+ }
+ List<Process> processes = ProcessBuilder.startPipeline(builders);
+ verifyProcesses(processes);
+ waitForAll(processes);
+ String result = fileContents(outfile);
+ System.out.printf(" in: %s%nout: %s%n", input, expected);
+ check(result.equals(expected), "result not as expected");
+ }
+
+ /**
+ * Wait for each of the processes to be done.
+ *
+ * @param processes the list of processes to check
+ */
+ static void waitForAll(List<Process> processes) {
+ processes.forEach(p -> {
+ try {
+ int status = p.waitFor();
+ } catch (InterruptedException ie) {
+ unexpected(ie);
+ }
+ });
+ }
+
+ static void print(ProcessBuilder pb) {
+ if (pb != null) {
+ System.out.printf(" pb: %s%n", pb);
+ System.out.printf(" cmd: %s%n", pb.command());
+ }
+ }
+
+ static void print(ProcessHandle p) {
+ System.out.printf("process: pid: %d, info: %s%n",
+ p.getPid(), p.info());
+ }
+
+ // Check various aspects of the processes
+ static void verifyProcesses(List<Process> processes) {
+ for (int i = 0; i < processes.size(); i++) {
+ Process p = processes.get(i);
+ if (i != 0) {
+ verifyNullStream(p.getOutputStream(), "getOutputStream");
+ }
+ if (i == processes.size() - 1) {
+ verifyNullStream(p.getInputStream(), "getInputStream");
+ verifyNullStream(p.getErrorStream(), "getErrorStream");
+ }
+ }
+ }
+
+ static void verifyNullStream(OutputStream s, String msg) {
+ try {
+ s.write(0xff);
+ fail("Stream should have been a NullStream" + msg);
+ } catch (IOException ie) {
+ // expected
+ }
+ }
+
+ static void verifyNullStream(InputStream s, String msg) {
+ try {
+ int len = s.read();
+ check(len == -1, "Stream should have been a NullStream" + msg);
+ } catch (IOException ie) {
+ // expected
+ }
+ }
+
+ static void setFileContents(File file, String contents) {
+ try {
+ Writer w = new FileWriter(file);
+ w.write(contents);
+ w.close();
+ } catch (Throwable t) { unexpected(t); }
+ }
+
+ static String fileContents(File file) {
+ try {
+ Reader r = new FileReader(file);
+ StringBuilder sb = new StringBuilder();
+ char[] buffer = new char[1024];
+ int n;
+ while ((n = r.read(buffer)) != -1)
+ sb.append(buffer,0,n);
+ r.close();
+ return new String(sb);
+ } catch (Throwable t) { unexpected(t); return ""; }
+ }
+
+ //--------------------- Infrastructure ---------------------------
+ static volatile int passed = 0, failed = 0;
+ static void pass() {passed++;}
+ static void fail() {failed++; Thread.dumpStack();}
+ static void fail(String msg) {System.err.println(msg); fail();}
+ static void unexpected(Throwable t) {failed++; t.printStackTrace();}
+ static void check(boolean cond) {if (cond) pass(); else fail();}
+ static void check(boolean cond, String m) {if (cond) pass(); else fail(m);}
+ static void equal(Object x, Object y) {
+ if (x == null ? y == null : x.equals(y)) pass();
+ else fail(">'" + x + "'<" + " not equal to " + "'" + y + "'");
+ }
+
+ public static void main(String[] args) throws Throwable {
+ try {realMain(args);} catch (Throwable t) {unexpected(t);}
+ System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
+ if (failed > 0) throw new AssertionError("Some tests failed");
+ }
+ interface Fun {void f() throws Throwable;}
+ static void THROWS(Class<? extends Throwable> k, Fun... fs) {
+ for (Fun f : fs)
+ try { f.f(); fail("Expected " + k.getName() + " not thrown"); }
+ catch (Throwable t) {
+ if (k.isAssignableFrom(t.getClass())) pass();
+ else unexpected(t);}
+ }
+
+}