/***** BEGIN LICENSE BLOCK *****
* Version: EPL 2.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 2.0 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.eclipse.org/legal/cpl-v10.html
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* Copyright (C) 2008 JRuby Community
*
* Alternatively, the contents of this file may be used under the terms of
* either of the GNU General Public License Version 2 or later (the "GPL"),
* or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
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package jnr.posix.util;
import java.io.
File;
import java.io.
IOException;
import java.io.
InputStream;
import java.io.
OutputStream;
import jnr.posix.
POSIXHandler;
public class
ExecIt {
protected final
POSIXHandler handler;
/** Creates a new instance of ShellLauncher
*
* @param handler the {@link POSIXHandler} to use
*/
public
ExecIt(
POSIXHandler handler) {
this.
handler =
handler;
}
public int
runAndWait(
String...
args) throws
IOException,
InterruptedException {
return
runAndWait(
handler.
getOutputStream(),
args);
}
public int
runAndWait(
OutputStream output,
String...
args) throws
IOException,
InterruptedException {
return
runAndWait(
output,
handler.
getErrorStream(),
args);
}
public int
runAndWait(
OutputStream output,
OutputStream error,
String...
args) throws
IOException,
InterruptedException {
Process process =
run(
args);
handleStreams(
process,
handler.
getInputStream(),
output,
error);
return
process.
waitFor();
}
public
Process run(
String...
args) throws
IOException {
File cwd =
handler.
getCurrentWorkingDirectory();
return
Runtime.
getRuntime().
exec(
args,
handler.
getEnv(),
cwd);
}
private static class
StreamPumper extends
Thread {
private
InputStream in;
private
OutputStream out;
private boolean
onlyIfAvailable;
private volatile boolean
quit;
private final
Object waitLock = new
Object();
StreamPumper(
InputStream in,
OutputStream out, boolean
avail) {
this.
in =
in;
this.
out =
out;
this.
onlyIfAvailable =
avail;
}
public void
run() {
byte[]
buf = new byte[1024];
int
numRead;
boolean
hasReadSomething = false;
try {
while (!
quit) {
// The problem we trying to solve below: STDIN in Java is blocked and
// non-interruptible, so if we invoke read on it, we might never be able to
// interrupt such thread. So, we use in.available() to see if there is any
// input ready, and only then read it. But this approach can't tell whether
// the end of stream reached or not, so we might end up looping right at the
// end of the stream. Well, at least, we can improve the situation by checking
// if some input was ever available, and if so, not checking for available
// anymore, and just go to read.
if (
onlyIfAvailable && !
hasReadSomething) {
if (
in.
available() == 0) {
synchronized (
waitLock) {
waitLock.
wait(10);
}
continue;
} else {
hasReadSomething = true;
}
}
if ((
numRead =
in.
read(
buf)) == -1) {
break;
}
out.
write(
buf, 0,
numRead);
}
} catch (
Exception e) {
} finally {
if (
onlyIfAvailable) {
// We need to close the out, since some
// processes would just wait for the stream
// to be closed before they process its content,
// and produce the output. E.g.: "cat".
try {
out.
close(); } catch (
IOException ioe) {}
}
}
}
public void
quit() {
this.
quit = true;
synchronized (
waitLock) {
waitLock.
notify();
}
}
}
private void
handleStreams(
Process p,
InputStream in,
OutputStream out,
OutputStream err) throws
IOException {
InputStream pOut =
p.
getInputStream();
InputStream pErr =
p.
getErrorStream();
OutputStream pIn =
p.
getOutputStream();
StreamPumper t1 = new
StreamPumper(
pOut,
out, false);
StreamPumper t2 = new
StreamPumper(
pErr,
err, false);
StreamPumper t3 = new
StreamPumper(
in,
pIn, true);
t1.
start();
t2.
start();
t3.
start();
try {
t1.
join(); } catch (
InterruptedException ie) {}
try {
t2.
join(); } catch (
InterruptedException ie) {}
t3.
quit();
try {
err.
flush(); } catch (
IOException io) {}
try {
out.
flush(); } catch (
IOException io) {}
try {
pIn.
close(); } catch (
IOException io) {}
try {
pOut.
close(); } catch (
IOException io) {}
try {
pErr.
close(); } catch (
IOException io) {}
}
}