org.jruby.runtime.load.ClassExtensionLibrary Maven / Gradle / Ivy
/***** BEGIN LICENSE BLOCK *****
* Version: EPL 1.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Eclipse Public
* License Version 1.0 (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/epl-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) 2006 Ola Bini
*
* 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
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the EPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the EPL, the GPL or the LGPL.
***** END LICENSE BLOCK *****/
package org.jruby.runtime.load;
import jnr.posix.JavaSecuredFile;
import org.jruby.Ruby;
import java.net.URL;
/**
* The ClassExtensionLibrary wraps a class which implements BasicLibraryService,
* and when asked to load the service, does a basicLoad of the BasicLibraryService.
*
* When the time comes to add other loading mechanisms for loading a class, this
* is the place where they will be added. The load method will check interface
* you can load a class with, and do the right thing.
*/
public class ClassExtensionLibrary implements Library {
private final Class theClass;
private final String name;
/**
* Try to locate an extension service in the current classloader resources. This happens
* after the jar has been added to JRuby's URLClassLoader (JRubyClassLoader) and is how
* extensions can magically load.
*
* The basic logic is to use the require name (@param searchName) to build the name of
* a class ending in "Service", and then invoke that class to boot the extension.
*
* The looping logic here was in response to a RubyGems change that started absolutizing
* the path to the extension jar under some circumstances, leading to an incorrect
* package/class name for the service contained therein. The new logic will try
* successively more trailing elements until one of them is not a valid package
* name or all elements have been exhausted.
*
* @param runtime the current JRuby runtime
* @param searchName the name passed to `require`
* @return a ClassExtensionLibrary that will boot the ext, or null if none was found
*/
static ClassExtensionLibrary tryFind(Ruby runtime, String searchName) {
// Create package name, by splitting on / and successively accumulating elements to form a class name
String[] elts = searchName.split("/");
boolean isAbsolute = new JavaSecuredFile(searchName).isAbsolute();
String simpleName = buildSimpleName(elts[elts.length - 1]);
int firstElement = isAbsolute ? elts.length - 1 : 0;
for (; firstElement >= 0; firstElement--) {
String className = buildClassName(elts, firstElement, elts.length - 1, simpleName);
ClassExtensionLibrary library = tryServiceLoad(runtime, className);
if (library != null) return library;
}
return null;
}
/**
* Build the "simple" part of a service class name from the given require path element
* by splitting on "_" and concatenating as CamelCase, plus "Service" suffix.
*
* @param element the element from which to build a simple service class name
* @return the resulting simple service class name
*/
private static String buildSimpleName(String element) {
StringBuilder nameBuilder = new StringBuilder(element.length() + "Service".length());
String[] last = element.split("_");
for (String part : last) {
if (part.isEmpty()) break;
nameBuilder
.append(Character.toUpperCase(part.charAt(0)))
.append(part, 1, part.length());
}
nameBuilder.append("Service");
return nameBuilder.toString();
}
/**
* Build the full class name for a service by joining the specified package elements
* with '.' and appending the given simple class name.
*
* @param elts the array from which to retrieve the package elements
* @param firstElement the first element to use
* @param end the end index at which to stop building the package name
* @param simpleName the simple class name for the service
* @return the full class name for the service
*/
private static String buildClassName(String[] elts, int firstElement, int end, String simpleName) {
StringBuilder nameBuilder = new StringBuilder();
for (int offset = firstElement; offset < end; offset++) {
// avoid blank elements from leading or double slashes
if (elts[offset].isEmpty()) continue;
nameBuilder
.append(elts[offset].toLowerCase())
.append('.');
}
nameBuilder.append(simpleName);
return nameBuilder.toString();
}
/**
* Try loading the given service class. Rather than raise ClassNotFoundException for
* jars that do not contain any service class, we require that the service class be a
* "normal" .class file accessible as a classloader resource. If it can be found
* using ClassLoader.getResource, we proceed to attempt to load it as a class.
*
* @param runtime the Ruby runtime into which the extension service will load
* @param className the class name of the service class
* @return a ClassExtensionLibrary if the service class was found; null otherwise.
*/
private static ClassExtensionLibrary tryServiceLoad(Ruby runtime, String className) {
String classFile = className.replaceAll("\\.", "/") + ".class";
try {
// quietly try to load the class, which must be reachable as a .class resource
URL resource = runtime.getJRubyClassLoader().getResource(classFile);
if (resource != null) {
Class theClass = runtime.getJavaSupport().loadJavaClass(className);
return new ClassExtensionLibrary(className + ".java", theClass);
}
} catch (ClassNotFoundException cnfe) {
if (runtime.isDebug()) cnfe.printStackTrace();
} catch (UnsupportedClassVersionError ucve) {
if (runtime.isDebug()) ucve.printStackTrace();
throw runtime.newLoadError("JRuby ext built for wrong Java version in `" + className + "': " + ucve, className);
}
// The class doesn't exist
return null;
}
public ClassExtensionLibrary(String name, Class extension) {
theClass = extension;
this.name = name;
}
public String getName() {
return name;
}
public void load(Ruby runtime, boolean wrap) {
if(BasicLibraryService.class.isAssignableFrom(theClass)) {
try {
runtime.loadExtension(name, (BasicLibraryService)theClass.newInstance(), wrap);
} catch(final Exception ee) {
throw new RuntimeException(ee.getMessage(),ee);
}
}
}
}
© 2015 - 2025 Weber Informatics LLC | Privacy Policy