/*
* ExtensionsClassLoader.java 2 sept. 2007
*
* Copyright (c) 2007-2008 Emmanuel PUYBARET / eTeks <info@eteks.com>. All Rights Reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Modified by Martin Pecka
*/
package cz.cuni.mff.peckam.java.origamist.utils;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.URLConnection;
import java.security.ProtectionDomain;
import java.util.Hashtable;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarFile;
/**
* Class loader able to load classes and DLLs with a higher priority from a given set of JARs.
* Its bytecode is Java 1.1 compatible to be loadable by old JVMs.
*
* @author Emmanuel Puybaret
*/
public class ExtensionClassLoader extends ClassLoader
{
protected final ProtectionDomain protectionDomain;
protected final List<String> applicationPackages;
protected URL base;
protected final Map<String, String> extensionDlls = new Hashtable<String, String>();
protected final Map<String, URL> extensionDllSources = new Hashtable<String, URL>();
protected final List<JarFile> extensionJars = new LinkedList<JarFile>();
/**
* Creates a class loader. It will consider JARs and DLLs of <code>extensionJarsAndDlls</code> as classpath and
* libclasspath elements with a higher priority than the ones of default classpath,
* and will load itself all the classes belonging to packages of <code>applicationPackages</code>.
*/
public ExtensionClassLoader(ClassLoader parent, ProtectionDomain protectionDomain,
List<String> extensionJarsAndDlls, List<String> applicationPackages, URL base)
{
super(parent);
this.protectionDomain = protectionDomain;
this.applicationPackages = applicationPackages;
this.base = base;
// Compute DLLs prefix and suffix
String dllSuffix;
String dllPrefix;
String osName = System.getProperty("os.name");
if (osName.startsWith("Windows")) {
dllSuffix = ".dll";
dllPrefix = "";
} else if (osName.startsWith("Mac OS X")) {
dllSuffix = ".jnilib";
dllPrefix = "lib";
} else {
dllSuffix = ".so";
dllPrefix = "lib";
}
// Find extension Jars and DLLs
for (String extensionJarOrDll : extensionJarsAndDlls) {
try {
URL extensionJarOrDllUrl = getResource(extensionJarOrDll);
if (extensionJarOrDllUrl != null) {
if (extensionJarOrDll.endsWith(".jar")) {
// Copy jar to a tmp file
String extensionJar = copyURLToCacheFile(extensionJarOrDllUrl, false);
// Add tmp file to extension jars list
extensionJars.add(new JarFile(extensionJar, false));
} else if (extensionJarOrDll.endsWith(dllSuffix)) {
int lastSlashIndex = extensionJarOrDll.lastIndexOf('/');
String key = extensionJarOrDll.substring(lastSlashIndex + 1 + dllPrefix.length(),
extensionJarOrDll.indexOf(dllSuffix));
// Copy DLL to a tmp file
String extensionDll = null;
try {
extensionDll = copyURLToCacheFile(extensionJarOrDllUrl, false);
// Add tmp file to extension DLLs map
this.extensionDlls.put(key, extensionDll);
this.extensionDllSources.put(key, extensionJarOrDllUrl);
} catch (FileInUseException e) {
// the native library is being used by another thread, so we need to make a copy of the
// library and use that copy
extensionDll = copyURLToCacheFile(extensionJarOrDllUrl, true);
// Add tmp file to extension DLLs map
this.extensionDlls.put(key, extensionDll);
// don't add the file's source to the map to indicate the randomized file has been used
// this.extensionDllSources.put(key, extensionJarOrDllUrl);
}
}
}
} catch (IOException ex) {
throw new RuntimeException("Couldn't extract extension JAR or native library " + extensionJarOrDll, ex);
}
}
}
@Override
public URL getResource(String name)
{
URL res = super.getResource(name);
if (res != null)
return res;
try {
URL url = new URL(base, name);
URI uri = url.toURI();
// File cannot handle remote URLs, so we must switch here...
// * File supports the exists() method
// * else we can get a HTTP/S URL, then we issue a HEAD request and test if the server returns 200
// * in all other cases (mabe a JAR URL or something) we just try to read from the URL, and if we succeed,
// we can claim the file exists
if ("file".equals(uri.getScheme()) && new File(uri).exists()) {
return url;
} else {
URLConnection connection = url.openConnection();
if (connection instanceof HttpURLConnection) {
HttpURLConnection httpConnection = (HttpURLConnection) connection;
httpConnection.setRequestMethod("HEAD");
if (httpConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
return url;
}
}
InputStream stream = null;
try {
stream = connection.getInputStream();
// this condition always holds, we just want to test if read() will throw exception
if (stream.read() >= -1) {
return url;
}
} catch (IOException e) {
} finally {
if (stream != null)
stream.close();
}
return null;
}
} catch (MalformedURLException e) {
return null;
} catch (URISyntaxException e) {
return null;
} catch (IOException e) {
return null;
}
}
/**
* Returns the file name of a cached local copy of <code>url</code> content.
*/
protected String copyURLToCacheFile(URL url, boolean addRandomStringToName) throws IOException
{
String filename = url.toString();
try {
if (!url.toURI().isAbsolute()) {
filename = new URL(base, filename).toString();
}
} catch (URISyntaxException e) {}
int dotIndex = filename.lastIndexOf(".");
String extension = null;
if (dotIndex > -1) {
extension = filename.substring(dotIndex, filename.length());
filename = filename.substring(0, dotIndex);
}
filename = filename.replaceAll("[^a-zA-Z0-9]", "");;
File file;
if (!addRandomStringToName) {
File tmpDir = new File(System.getProperty("java.io.tmpdir"), ".").getAbsoluteFile().getCanonicalFile();
file = new File(tmpDir, filename + extension);
} else {
file = File.createTempFile(filename, extension);
file.deleteOnExit();
}
InputStream input = url.openStream();
OutputStream output = null;
try {
output = new BufferedOutputStream(new FileOutputStream(file));
byte[] buffer = new byte[8192];
int size;
while ((size = input.read(buffer)) != -1) {
output.write(buffer, 0, size);
}
file.setExecutable(true, false);
} catch (FileNotFoundException e) {
if (file.exists())
// FileNotFoundException thrown while the file exists means the file cannot be read
throw new FileInUseException();
else
throw e;
} finally {
if (input != null) {
input.close();
}
if (output != null) {
output.close();
}
}
return file.toString();
}
/**
* Finds and defines the given class among the extension JARs given in constructor, then among resources.
*/
protected Class<?> findClass(String name) throws ClassNotFoundException
{
// Build class file from its name
String classFile = name.replace('.', '/') + ".class";
InputStream classInputStream = null;
// Check if searched class is an extension class
for (JarFile extensionJar : this.extensionJars) {
JarEntry jarEntry = extensionJar.getJarEntry(classFile);
if (jarEntry != null) {
try {
classInputStream = extensionJar.getInputStream(jarEntry);
} catch (IOException ex) {
throw new ClassNotFoundException("Couldn't read class " + name, ex);
}
}
}
// If it's not an extension class, search if its an application
// class that can be read from resources
if (classInputStream == null) {
URL url = getResource(classFile);
if (url == null) {
throw new ClassNotFoundException("Class " + name);
}
try {
classInputStream = url.openStream();
} catch (IOException ex) {
throw new ClassNotFoundException("Couldn't read class " + name, ex);
}
}
try {
// Read class input content to a byte array
ByteArrayOutputStream out = new ByteArrayOutputStream();
BufferedInputStream in = new BufferedInputStream(classInputStream);
byte[] buffer = new byte[8192];
int size;
while ((size = in.read(buffer)) != -1) {
out.write(buffer, 0, size);
}
in.close();
// Define class
return defineClass(name, out.toByteArray(), 0, out.size(), this.protectionDomain);
} catch (IOException ex) {
throw new ClassNotFoundException("Class " + name, ex);
}
}
/**
* Returns the library path of an extension DLL.
*/
@Override
protected String findLibrary(String libname)
{
String result = this.extensionDlls.get(libname);
if (result != null) {
// HACK ! If you load eg. editor as applet, and then load viewer, or if you just want to have multiple
// instances running, Java would deny multiple access to the native libraries. The hack is that when
// searching for the name of a library, we also try to load it, and if it fails, we know we need to copy the
// library and load that copy.
try {
System.loadLibrary(libname);
} catch (UnsatisfiedLinkError e) {
// the library is loaded by another classloader
try {
URL source = this.extensionDllSources.get(libname);
if (source != null) {
result = copyURLToCacheFile(source, true);
this.extensionDlls.put(libname, result);
}
} catch (IOException e1) {}
}
return result;
}
return super.findLibrary(libname);
}
/**
* Returns the URL of the given resource searching first if it exists among the extension JARs given in constructor.
*/
protected URL findResource(String name)
{
// Try to find if resource belongs to one of the extracted jars
for (JarFile extensionJar : this.extensionJars) {
JarEntry jarEntry = extensionJar.getJarEntry(name);
if (jarEntry != null) {
try {
return new URL("jar:file:" + extensionJar.getName() + ":" + jarEntry.getName());
} catch (MalformedURLException ex) {
break;
}
}
}
return super.findResource(name);
}
/**
* Loads a class with this class loader if its package belongs to <code>applicationPackages</code> given in
* constructor.
*/
protected synchronized Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException
{
// If no extension jars were found
if (this.extensionJars.size() == 0) {
// Let default class loader do its job
return super.loadClass(name, resolve);
}
// Check if the class has already been loaded
Class<?> loadedClass = findLoadedClass(name);
if (loadedClass == null) {
try {
// Try to find if class belongs to one of the application packages
for (String applicationPackage : this.applicationPackages) {
int applicationPackageLength = applicationPackage.length();
if ((applicationPackageLength == 0 && name.indexOf('.') == 0)
|| (applicationPackageLength > 0 && name.startsWith(applicationPackage))) {
loadedClass = findClass(name);
break;
}
}
} catch (ClassNotFoundException ex) {
// Let a chance to class to be loaded by default implementation
}
if (loadedClass == null) {
loadedClass = super.loadClass(name, resolve);
}
}
if (resolve) {
resolveClass(loadedClass);
}
return loadedClass;
}
/**
* This exception is thrown if a file is to be opened but some other application has it exclusively open.
*
* @author Martin Pecka
*/
protected class FileInUseException extends IOException
{
/** */
private static final long serialVersionUID = -713063084550677154L;
}
}