stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8132541: (process) ProcessBuilder support for redirection to discard output

Browse Source 
Add redirect to NUL or /dev/null depending on the OS

Reviewed-by: chegar, martin
This commit is contained in:
Roger Riggs 2015-09-23 11:18:34 -04:00
parent f1f609ddaa
commit 4e7617c040
2 changed files with 125 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
jdk/src/java.base/share/classes/java/lang/ProcessBuilder.java
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2003, 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
@ -33,7 +33,8 @@ import java.util.Arrays;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.security.AccessController;
import java.security.PrivilegedAction;
/**
* This class is used to create operating system processes.
*
@ -445,6 +446,7 @@ public final class ProcessBuilder
* <ul>
* <li>the special value {@link #PIPE Redirect.PIPE}
* <li>the special value {@link #INHERIT Redirect.INHERIT}
* <li>the special value {@link #DISCARD Redirect.DISCARD}
* <li>a redirection to read from a file, created by an invocation of
* {@link Redirect#from Redirect.from(File)}
* <li>a redirection to write to a file, created by an invocation of
@ -459,6 +461,13 @@ public final class ProcessBuilder
* @since 1.7
*/
public abstract static class Redirect {
private static final File NULL_FILE = AccessController.doPrivileged(
(PrivilegedAction<File>) () -> {
return new File((System.getProperty("os.name")
.startsWith("Windows") ? "NUL" : "/dev/null"));
}
);
/**
* The type of a {@link Redirect}.
*/
@ -529,6 +538,28 @@ public final class ProcessBuilder
public Type type() { return Type.INHERIT; }
public String toString() { return type().toString(); }};
/**
* Indicates that subprocess output will be discarded.
* A typical implementation discards the output by writing to
* an operating system specific "null file".
*
* <p>It will always be true that
* <pre> {@code
* Redirect.DISCARD.file() the filename appropriate for the operating system
* and may be null &&
* Redirect.DISCARD.type() == Redirect.Type.WRITE &&
* Redirect.DISCARD.append() == false
* }</pre>
* @since 9
*/
public static final Redirect DISCARD = new Redirect() {
public Type type() { return Type.WRITE; }
public String toString() { return type().toString(); }
public File file() { return NULL_FILE; }
boolean append() { return false; }
};
/**
* Returns the {@link File} source or destination associated
* with this redirect, or {@code null} if there is no such file.

99
jdk/test/java/lang/ProcessBuilder/Basic.java
View File

@ -738,7 +738,7 @@ public class Basic {
* Remove it from the list of env variables
*/
private static String removeAixExpectedVars(String vars) {
return vars.replace("AIXTHREAD_GUARDPAGES=0,","");
return vars.replace("AIXTHREAD_GUARDPAGES=0,", "");
}
private static String sortByLinesWindowsly(String text) {
@ -785,8 +785,8 @@ public class Basic {
equal(entry.getKey(), key);
equal(entry.getValue(), value);
}
check(! kIter.hasNext() &&
! vIter.hasNext());
check(!kIter.hasNext() &&
!vIter.hasNext());
} catch (Throwable t) { unexpected(t); }
}
@ -815,9 +815,9 @@ public class Basic {
static void checkRedirects(ProcessBuilder pb,
Redirect in, Redirect out, Redirect err) {
equal(pb.redirectInput(), in);
equal(pb.redirectInput(), in);
equal(pb.redirectOutput(), out);
equal(pb.redirectError(), err);
equal(pb.redirectError(), err);
}
static void redirectIO(ProcessBuilder pb,
@ -862,6 +862,7 @@ public class Basic {
Redirect[] redirects =
{ PIPE,
INHERIT,
DISCARD,
Redirect.from(ifile),
Redirect.to(ifile),
Redirect.appendTo(ifile),
@ -884,6 +885,10 @@ public class Basic {
equal(INHERIT.toString(), "INHERIT");
equal(INHERIT.file(), null);
equal(DISCARD.type(), Redirect.Type.WRITE);
equal(DISCARD.toString(), "WRITE");
equal(DISCARD.file(), new File((Windows.is() ? "NUL" : "/dev/null")));
equal(Redirect.from(ifile).type(), Redirect.Type.READ);
equal(Redirect.from(ifile).toString(),
"redirect to read from file \"ifile\"");
@ -925,6 +930,12 @@ public class Basic {
pb.inheritIO();
checkRedirects(pb, INHERIT, INHERIT, INHERIT);
//----------------------------------------------------------------
// Check DISCARD for stdout,stderr
//----------------------------------------------------------------
redirectIO(pb, INHERIT, DISCARD, DISCARD);
checkRedirects(pb, INHERIT, DISCARD, DISCARD);
//----------------------------------------------------------------
// Check setters and getters agree
//----------------------------------------------------------------
@ -943,7 +954,8 @@ public class Basic {
THROWS(IllegalArgumentException.class,
() -> pb.redirectInput(Redirect.to(ofile)),
() -> pb.redirectOutput(Redirect.from(ifile)),
() -> pb.redirectError(Redirect.from(ifile)));
() -> pb.redirectError(Redirect.from(ifile)),
() -> pb.redirectInput(DISCARD));
THROWS(NullPointerException.class,
() -> pb.redirectInput((File)null),
@ -980,7 +992,7 @@ public class Basic {
ProcessResults r = run(pb);
equal(r.exitValue(), 0);
equal(fileContents(ofile),
"standard error" + "standard output");
"standard error" + "standard output");
equal(fileContents(efile), "");
equal(r.out(), "");
equal(r.err(), "");
@ -1050,6 +1062,79 @@ public class Basic {
efile.delete();
}
//----------------------------------------------------------------
// DISCARDing output
//----------------------------------------------------------------
{
setFileContents(ifile, "standard input");
pb.redirectOutput(DISCARD);
pb.redirectError(DISCARD);
ProcessResults r = run(pb);
equal(r.exitValue(), 0);
equal(r.out(), "");
equal(r.err(), "");
}
//----------------------------------------------------------------
// DISCARDing output and redirecting error
//----------------------------------------------------------------
{
setFileContents(ifile, "standard input");
setFileContents(ofile, "ofile-contents");
setFileContents(efile, "efile-contents");
pb.redirectOutput(DISCARD);
pb.redirectError(efile);
ProcessResults r = run(pb);
equal(r.exitValue(), 0);
equal(fileContents(ofile), "ofile-contents");
equal(fileContents(efile), "standard error");
equal(r.out(), "");
equal(r.err(), "");
ofile.delete();
efile.delete();
}
//----------------------------------------------------------------
// DISCARDing error and redirecting output
//----------------------------------------------------------------
{
setFileContents(ifile, "standard input");
setFileContents(ofile, "ofile-contents");
setFileContents(efile, "efile-contents");
pb.redirectOutput(ofile);
pb.redirectError(DISCARD);
ProcessResults r = run(pb);
equal(r.exitValue(), 0);
equal(fileContents(ofile), "standard output");
equal(fileContents(efile), "efile-contents");
equal(r.out(), "");
equal(r.err(), "");
ofile.delete();
efile.delete();
}
//----------------------------------------------------------------
// DISCARDing output and merging error into output
//----------------------------------------------------------------
{
setFileContents(ifile, "standard input");
setFileContents(ofile, "ofile-contents");
setFileContents(efile, "efile-contents");
pb.redirectOutput(DISCARD);
pb.redirectErrorStream(true);
pb.redirectError(efile);
ProcessResults r = run(pb);
equal(r.exitValue(), 0);
equal(fileContents(ofile), "ofile-contents"); // untouched
equal(fileContents(efile), ""); // empty
equal(r.out(), "");
equal(r.err(), "");
ifile.delete();
ofile.delete();
efile.delete();
pb.redirectErrorStream(false); // reset for next test
}
//----------------------------------------------------------------
// Testing INHERIT is harder.
// Note that this requires __FOUR__ nested JVMs involved in one test,