com.google.gerrit.common.IoUtil Maven / Gradle / Ivy
// Copyright (C) 2009 The Android Open Source Project
//
// Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package com.google.gerrit.common;
import com.google.common.collect.Sets;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.file.Path;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Set;
public final class IoUtil {
public static void copyWithThread(InputStream src, OutputStream dst) {
new Thread("IoUtil-Copy") {
// We cannot propagate the exception since this code is running in a background thread.
// Printing the stacktrace is the best we can do. Hence ignoring the exception after printing
// the stacktrace is OK and it's fine to suppress the warning for the CatchAndPrintStackTrace
// bug pattern here.
@SuppressWarnings("CatchAndPrintStackTrace")
@Override
public void run() {
try {
copyIo();
} catch (IOException e) {
e.printStackTrace();
}
}
private void copyIo() throws IOException {
try {
final byte[] buf = new byte[256];
int n;
while (0 < (n = src.read(buf))) {
dst.write(buf, 0, n);
}
} finally {
try {
src.close();
} catch (IOException e2) {
// Ignore
}
}
}
}.start();
}
public static void loadJARs(Collection jars) {
if (jars.isEmpty()) {
return;
}
ClassLoader cl = IoUtil.class.getClassLoader();
if (!(cl instanceof URLClassLoader)) {
throw noAddURL("Not loaded by URLClassLoader", null);
}
@SuppressWarnings("resource") // Leave open so classes can be loaded.
URLClassLoader urlClassLoader = (URLClassLoader) cl;
Method addURL;
try {
addURL = URLClassLoader.class.getDeclaredMethod("addURL", URL.class);
addURL.setAccessible(true);
} catch (SecurityException | NoSuchMethodException e) {
throw noAddURL("Method addURL not available", e);
}
Set have = Sets.newHashSet(Arrays.asList(urlClassLoader.getURLs()));
for (Path path : jars) {
try {
URL url = path.toUri().toURL();
if (have.add(url)) {
addURL.invoke(cl, url);
}
} catch (MalformedURLException | IllegalArgumentException | IllegalAccessException e) {
throw noAddURL("addURL " + path + " failed", e);
} catch (InvocationTargetException e) {
throw noAddURL("addURL " + path + " failed", e.getCause());
}
}
}
public static void loadJARs(Path jar) {
loadJARs(Collections.singleton(jar));
}
private static UnsupportedOperationException noAddURL(String m, Throwable why) {
String prefix = "Cannot extend classpath: ";
return new UnsupportedOperationException(prefix + m, why);
}
private IoUtil() {}
}