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Customize creation mode for custom RedirectPipe instances
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@gnodet
gnodet committed Oct 3, 2023
1 parent 94440d0 commit 07f5fb5
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Showing 2 changed files with 92 additions and 14 deletions.
9 changes: 9 additions & 0 deletions terminal/src/main/java/org/jline/terminal/TerminalBuilder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,15 @@ public final class TerminalBuilder {
public static final String PROP_FILE_DESCRIPTOR_CREATION_MODE_REFLECTION = "reflection";
public static final String PROP_FILE_DESCRIPTOR_CREATION_MODE_DEFAULT = "reflection,native";

//
// System properties controlling how RedirectPipe are created.
// The value can be a comma separated list of defined mechanisms.
//
public static final String PROP_REDIRECT_PIPE_CREATION_MODE = "org.jline.terminal.exec.redirectPipeCreationMode";
public static final String PROP_REDIRECT_PIPE_CREATION_MODE_NATIVE = "native";
public static final String PROP_REDIRECT_PIPE_CREATION_MODE_REFLECTION = "reflection";
public static final String PROP_REDIRECT_PIPE_CREATION_MODE_DEFAULT = "reflection,native";

//
// Terminal output control
//
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97 changes: 83 additions & 14 deletions terminal/src/main/java/org/jline/terminal/impl/exec/ExecTerminalProvider.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@
import java.lang.reflect.Field;
import java.nio.charset.Charset;

import org.jline.nativ.JLineLibrary;
import org.jline.nativ.JLineNativeLoader;
import org.jline.terminal.Attributes;
import org.jline.terminal.Size;
import org.jline.terminal.Terminal;
Expand All @@ -28,6 +30,11 @@
import org.jline.utils.Log;
import org.jline.utils.OSUtils;

import static org.jline.terminal.TerminalBuilder.PROP_REDIRECT_PIPE_CREATION_MODE;
import static org.jline.terminal.TerminalBuilder.PROP_REDIRECT_PIPE_CREATION_MODE_DEFAULT;
import static org.jline.terminal.TerminalBuilder.PROP_REDIRECT_PIPE_CREATION_MODE_NATIVE;
import static org.jline.terminal.TerminalBuilder.PROP_REDIRECT_PIPE_CREATION_MODE_REFLECTION;

public class ExecTerminalProvider implements TerminalProvider {

private static boolean warned;
Expand Down Expand Up @@ -137,7 +144,7 @@ public String systemStreamName(Stream stream) {
try {
ProcessBuilder.Redirect input = stream == Stream.Input
? ProcessBuilder.Redirect.INHERIT
: getRedirect(stream == Stream.Output ? FileDescriptor.out : FileDescriptor.err);
: newDescriptor(stream == Stream.Output ? FileDescriptor.out : FileDescriptor.err);
Process p =
new ProcessBuilder(OSUtils.TTY_COMMAND).redirectInput(input).start();
String result = ExecHelper.waitAndCapture(p);
Expand All @@ -157,20 +164,82 @@ public String systemStreamName(Stream stream) {
return null;
}

private static RedirectPipeCreator redirectPipeCreator;

protected static ProcessBuilder.Redirect newDescriptor(FileDescriptor fd) {
if (redirectPipeCreator == null) {
String str = System.getProperty(PROP_REDIRECT_PIPE_CREATION_MODE, PROP_REDIRECT_PIPE_CREATION_MODE_DEFAULT);
String[] modes = str.split(",");
IllegalStateException ise = new IllegalStateException("Unable to create RedirectPipe");
for (String mode : modes) {
try {
switch (mode) {
case PROP_REDIRECT_PIPE_CREATION_MODE_NATIVE:
redirectPipeCreator = new NativeRedirectPipeCreator();
break;
case PROP_REDIRECT_PIPE_CREATION_MODE_REFLECTION:
redirectPipeCreator = new ReflectionRedirectPipeCreator();
break;
}
} catch (Throwable t) {
// ignore
ise.addSuppressed(t);
}
if (redirectPipeCreator != null) {
break;
}
}
if (redirectPipeCreator == null) {
throw ise;
}
}
return redirectPipeCreator.newRedirectPipe(fd);
}

interface RedirectPipeCreator {
ProcessBuilder.Redirect newRedirectPipe(FileDescriptor fd);
}

/**
* This requires --add-opens java.base/java.lang=ALL-UNNAMED
* Reflection based file descriptor creator.
* This requires the following option
* --add-opens java.base/java.lang=ALL-UNNAMED
*/
private ProcessBuilder.Redirect getRedirect(FileDescriptor fd) throws ReflectiveOperationException {
// This is not really allowed, but this is the only way to redirect the output or error stream
// to the input. This is definitely not something you'd usually want to do, but in the case of
// the `tty` utility, it provides a way to get
Class<?> rpi = Class.forName("java.lang.ProcessBuilder$RedirectPipeImpl");
Constructor<?> cns = rpi.getDeclaredConstructor();
cns.setAccessible(true);
ProcessBuilder.Redirect input = (ProcessBuilder.Redirect) cns.newInstance();
Field f = rpi.getDeclaredField("fd");
f.setAccessible(true);
f.set(input, fd);
return input;
static class ReflectionRedirectPipeCreator implements RedirectPipeCreator {
private final Constructor<ProcessBuilder.Redirect> constructor;
private final Field fdField;

@SuppressWarnings("unchecked")
ReflectionRedirectPipeCreator() throws Exception {
Class<?> rpi = Class.forName("java.lang.ProcessBuilder$RedirectPipeImpl");
constructor = (Constructor<ProcessBuilder.Redirect>) rpi.getDeclaredConstructor();
constructor.setAccessible(true);
fdField = rpi.getDeclaredField("fd");
fdField.setAccessible(true);
}

@Override
public ProcessBuilder.Redirect newRedirectPipe(FileDescriptor fd) {
try {
ProcessBuilder.Redirect input = constructor.newInstance();
fdField.set(input, fd);
return input;
} catch (ReflectiveOperationException e) {
// This should not happen as the field has been set accessible
throw new IllegalStateException(e);
}
}
}

static class NativeRedirectPipeCreator implements RedirectPipeCreator {
public NativeRedirectPipeCreator() {
// Force load the library
JLineNativeLoader.initialize();
}

@Override
public ProcessBuilder.Redirect newRedirectPipe(FileDescriptor fd) {
return JLineLibrary.newRedirectPipe(fd);
}
}
}

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