org.apache.felix.framework.URLHandlers Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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 org.apache.felix.framework;
import java.net.ContentHandler;
import java.net.ContentHandlerFactory;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;
import java.net.URLStreamHandlerFactory;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;
import org.apache.felix.framework.util.FelixConstants;
import org.apache.felix.framework.util.SecureAction;
import org.apache.felix.framework.util.SecurityManagerEx;
import org.osgi.service.url.URLStreamHandlerService;
/**
*
* This class is a singleton and implements the stream and content handler
* factories for all framework instances executing within the JVM. Any
* calls to retrieve stream or content handlers is routed through this class
* and it acts as a multiplexer for all framework instances. To achieve this,
* all framework instances register with this class when they are created so
* that it can maintain a centralized registry of instances.
*
*
* When this class receives a request for a stream or content handler, it
* always returns a proxy handler instead of only returning a proxy if a
* handler currently exists. This approach is used for three reasons:
*
*
* - Potential caching behavior by the JVM of stream handlers does not give
* you a second chance to provide a handler.
*
* - Due to the dynamic nature of OSGi services, handlers may appear at
* any time, so always creating a proxy makes sense.
*
* - Since these handler factories service all framework instances,
* some instances may have handlers and others may not, so returning
* a proxy is the only answer that makes sense.
*
*
*
* It is possible to disable the URL Handlers service by setting the
* framework.service.urlhandlers configuration property to false.
* When multiple framework instances are in use, if no framework instances enable
* the URL Handlers service, then the singleton stream and content factories will
* never be set (i.e., URL.setURLStreamHandlerFactory() and
* URLConnection.setContentHandlerFactory()). However, if one instance
* enables URL Handlers service, then the factory methods will be invoked. In
* that case, framework instances that disable the URL Handlers service will
* simply not provide that services to their contained bundles, while framework
* instances with the service enabled will.
*
**/
class URLHandlers implements URLStreamHandlerFactory, ContentHandlerFactory
{
private static final Class[] CLASS_TYPE = new Class[]{Class.class};
private static final Class URLHANDLERS_CLASS = URLHandlers.class;
private static final SecureAction m_secureAction = new SecureAction();
private static volatile SecurityManagerEx m_sm = null;
private static volatile URLHandlers m_handler = null;
// This maps classloaders of URLHandlers in other classloaders to lists of
// their frameworks.
private final static Map m_classloaderToFrameworkLists = new HashMap();
// The list to hold all enabled frameworks registered with this handlers
private static final List m_frameworks = new ArrayList();
private static int m_counter = 0;
private static Map m_contentHandlerCache = null;
private static Map m_streamHandlerCache = null;
private static URLStreamHandlerFactory m_streamHandlerFactory;
private static ContentHandlerFactory m_contentHandlerFactory;
private static final String STREAM_HANDLER_PACKAGE_PROP = "java.protocol.handler.pkgs";
private static final String DEFAULT_STREAM_HANDLER_PACKAGE = "sun.net.www.protocol|com.ibm.oti.net.www.protocol|gnu.java.net.protocol|wonka.net|com.acunia.wonka.net|org.apache.harmony.luni.internal.net.www.protocol|weblogic.utils|weblogic.net|javax.net.ssl|COM.newmonics.www.protocols";
private static Object m_rootURLHandlers;
private static final String m_streamPkgs;
private static final Map m_builtIn = new HashMap();
private static final boolean m_loaded;
static
{
String pkgs = new SecureAction().getSystemProperty(STREAM_HANDLER_PACKAGE_PROP, "");
m_streamPkgs = (pkgs.equals(""))
? DEFAULT_STREAM_HANDLER_PACKAGE
: pkgs + "|" + DEFAULT_STREAM_HANDLER_PACKAGE;
m_loaded = (null != URLHandlersStreamHandlerProxy.class) &&
(null != URLHandlersContentHandlerProxy.class) && (null != URLStreamHandlerService.class);
}
private static final Map m_handlerToURL = new HashMap();
private void init(String protocol, URLStreamHandlerFactory factory)
{
try
{
URLStreamHandler handler = getBuiltInStreamHandler(protocol, factory);
if (handler != null)
{
URL url = new URL(protocol, null, -1, "", handler);
m_handlerToURL.put(handler, url);
}
}
catch (Throwable ex)
{
// Ignore, this is a best effort (maybe log it or something).
}
}
/**
*
* Only one instance of this class is created per classloader
* and that one instance is registered as the stream and content handler
* factories for the JVM. Unless, we already register one from a different
* classloader. In this case we attach to this root.
*
**/
private URLHandlers()
{
m_sm = new SecurityManagerEx();
synchronized (URL.class)
{
URLStreamHandlerFactory currentFactory = null;
try
{
currentFactory = (URLStreamHandlerFactory) m_secureAction.swapStaticFieldIfNotClass(URL.class,
URLStreamHandlerFactory.class, URLHANDLERS_CLASS, "streamHandlerLock");
}
catch (Throwable ex)
{
// Ignore, this is a best effort (maybe log it or something)
}
init("file", currentFactory);
init("ftp", currentFactory);
init("http", currentFactory);
init("https", currentFactory);
try
{
getBuiltInStreamHandler("jar", currentFactory);
}
catch (Throwable ex)
{
// Ignore, this is a best effort (maybe log it or something)
}
if (currentFactory != null)
{
try
{
URL.setURLStreamHandlerFactory(currentFactory);
}
catch (Throwable ex)
{
// Ignore, this is a best effort (maybe log it or something)
}
}
try
{
URL.setURLStreamHandlerFactory(this);
m_streamHandlerFactory = this;
m_rootURLHandlers = this;
// try to flush the cache (gnu/classpath doesn't do it itself)
try
{
m_secureAction.flush(URL.class, URL.class);
}
catch (Throwable t)
{
// Not much we can do
}
}
catch (Error err)
{
try
{
// there already is a factory set so try to swap it with ours.
m_streamHandlerFactory = (URLStreamHandlerFactory)
m_secureAction.swapStaticFieldIfNotClass(URL.class,
URLStreamHandlerFactory.class, URLHANDLERS_CLASS, "streamHandlerLock");
if (m_streamHandlerFactory == null)
{
throw err;
}
if (!m_streamHandlerFactory.getClass().getName().equals(URLHANDLERS_CLASS.getName()))
{
URL.setURLStreamHandlerFactory(this);
m_rootURLHandlers = this;
}
else if (URLHANDLERS_CLASS != m_streamHandlerFactory.getClass())
{
try
{
m_secureAction.invoke(
m_secureAction.getDeclaredMethod(m_streamHandlerFactory.getClass(),
"registerFrameworkListsForContextSearch",
new Class[]{ClassLoader.class, List.class}),
m_streamHandlerFactory, new Object[]{ URLHANDLERS_CLASS.getClassLoader(),
m_frameworks });
m_rootURLHandlers = m_streamHandlerFactory;
}
catch (Exception ex)
{
throw new RuntimeException(ex.getMessage());
}
}
}
catch (Exception e)
{
throw err;
}
}
try
{
URLConnection.setContentHandlerFactory(this);
m_contentHandlerFactory = this;
// try to flush the cache (gnu/classpath doesn't do it itself)
try
{
m_secureAction.flush(URLConnection.class, URLConnection.class);
}
catch (Throwable t)
{
// Not much we can do
}
}
catch (Error err)
{
// there already is a factory set so try to swap it with ours.
try
{
m_contentHandlerFactory = (ContentHandlerFactory)
m_secureAction.swapStaticFieldIfNotClass(
URLConnection.class, ContentHandlerFactory.class,
URLHANDLERS_CLASS, null);
if (m_contentHandlerFactory == null)
{
throw err;
}
if (!m_contentHandlerFactory.getClass().getName().equals(
URLHANDLERS_CLASS.getName()))
{
URLConnection.setContentHandlerFactory(this);
}
}
catch (Exception ex)
{
throw err;
}
}
}
// are we not the new root?
if (!((m_streamHandlerFactory == this) || !URLHANDLERS_CLASS.getName().equals(
m_streamHandlerFactory.getClass().getName())))
{
m_sm = null;
m_handlerToURL.clear();
m_builtIn.clear();
}
}
static void registerFrameworkListsForContextSearch(ClassLoader index,
List frameworkLists)
{
synchronized (URL.class)
{
synchronized (m_classloaderToFrameworkLists)
{
m_classloaderToFrameworkLists.put(index, frameworkLists);
}
}
}
static void unregisterFrameworkListsForContextSearch(ClassLoader index)
{
synchronized (URL.class)
{
synchronized (m_classloaderToFrameworkLists)
{
m_classloaderToFrameworkLists.remove(index);
if (m_classloaderToFrameworkLists.isEmpty() )
{
synchronized (m_frameworks)
{
if (m_frameworks.isEmpty())
{
try
{
m_secureAction.swapStaticFieldIfNotClass(URL.class,
URLStreamHandlerFactory.class, null, "streamHandlerLock");
}
catch (Exception ex)
{
// TODO log this
ex.printStackTrace();
}
if (m_streamHandlerFactory.getClass() != URLHANDLERS_CLASS)
{
URL.setURLStreamHandlerFactory(m_streamHandlerFactory);
}
try
{
m_secureAction.swapStaticFieldIfNotClass(
URLConnection.class, ContentHandlerFactory.class,
null, null);
}
catch (Exception ex)
{
// TODO log this
ex.printStackTrace();
}
if (m_contentHandlerFactory.getClass() != URLHANDLERS_CLASS)
{
URLConnection.setContentHandlerFactory(m_contentHandlerFactory);
}
}
}
}
}
}
}
private URLStreamHandler getBuiltInStreamHandler(String protocol, URLStreamHandlerFactory factory)
{
synchronized (m_builtIn)
{
if (m_builtIn.containsKey(protocol))
{
return (URLStreamHandler) m_builtIn.get(protocol);
}
}
if (factory != null)
{
URLStreamHandler result = factory.createURLStreamHandler(protocol);
if (result != null)
{
return addToCache(protocol, result);
}
}
// Check for built-in handlers for the mime type.
// Iterate over built-in packages.
URLStreamHandler handler = loadBuiltInStreamHandler(protocol, null);
if (handler == null)
{
handler = loadBuiltInStreamHandler(protocol, ClassLoader.getSystemClassLoader());
}
return addToCache(protocol, handler);
}
private URLStreamHandler loadBuiltInStreamHandler(String protocol, ClassLoader classLoader) {
StringTokenizer pkgTok = new StringTokenizer(m_streamPkgs, "| ");
while (pkgTok.hasMoreTokens())
{
String pkg = pkgTok.nextToken().trim();
String className = pkg + "." + protocol + ".Handler";
try
{
// If a built-in handler is found then cache and return it
Class handler = m_secureAction.forName(className, classLoader);
if (handler != null)
{
return (URLStreamHandler) handler.newInstance();
}
}
catch (Throwable ex)
{
// This could be a class not found exception or an
// instantiation exception, not much we can do in either
// case other than ignore it.
}
}
// This is a workaround for android - Starting with 4.1 the built-in core handler
// are not following the normal naming nore package schema :-(
String androidHandler = null;
if ("file".equalsIgnoreCase(protocol))
{
androidHandler = "libcore.net.url.FileHandler";
}
else if ("ftp".equalsIgnoreCase(protocol))
{
androidHandler = "libcore.net.url.FtpHandler";
}
else if ("http".equalsIgnoreCase(protocol))
{
androidHandler = "libcore.net.http.HttpHandler";
}
else if ("https".equalsIgnoreCase(protocol))
{
androidHandler = "libcore.net.http.HttpsHandler";
}
else if ("jar".equalsIgnoreCase(protocol))
{
androidHandler = "libcore.net.url.JarHandler";
}
if (androidHandler != null)
{
try
{
// If a built-in handler is found then cache and return it
Class handler = m_secureAction.forName(androidHandler, classLoader);
if (handler != null)
{
return (URLStreamHandler) handler.newInstance();
}
}
catch (Throwable ex)
{
// This could be a class not found exception or an
// instantiation exception, not much we can do in either
// case other than ignore it.
}
}
return null;
}
private synchronized URLStreamHandler addToCache(String protocol, URLStreamHandler result)
{
if (!m_builtIn.containsKey(protocol))
{
m_builtIn.put(protocol, result);
return result;
}
return (URLStreamHandler) m_builtIn.get(protocol);
}
/**
*
* This is a method implementation for the URLStreamHandlerFactory
* interface. It simply creates a stream handler proxy object for the
* specified protocol. It caches the returned proxy; therefore, subsequent
* requests for the same protocol will receive the same handler proxy.
*
* @param protocol the protocol for which a stream handler should be returned.
* @return a stream handler proxy for the specified protocol.
**/
public URLStreamHandler createURLStreamHandler(String protocol)
{
// See if there is a cached stream handler.
// IMPLEMENTATION NOTE: Caching is not strictly necessary for
// stream handlers since the Java runtime caches them. Caching is
// performed for code consistency between stream and content
// handlers and also because caching behavior may not be guaranteed
// across different JRE implementations.
URLStreamHandler handler = getFromStreamCache(protocol);
if (handler != null)
{
return handler;
}
// If this is the framework's "bundle:" protocol, then return
// a handler for that immediately, since no one else can be
// allowed to deal with it.
if (protocol.equals(FelixConstants.BUNDLE_URL_PROTOCOL))
{
return addToStreamCache(protocol,
new URLHandlersBundleStreamHandler(m_secureAction));
}
handler = getBuiltInStreamHandler(protocol,
(m_streamHandlerFactory != this) ? m_streamHandlerFactory : null);
// If built-in content handler, then create a proxy handler.
return addToStreamCache(protocol,
new URLHandlersStreamHandlerProxy(protocol, m_secureAction,
handler, (URL) m_handlerToURL.get(handler)));
}
/**
*
* This is a method implementation for the ContentHandlerFactory
* interface. It simply creates a content handler proxy object for the
* specified mime type. It caches the returned proxy; therefore, subsequent
* requests for the same content type will receive the same handler proxy.
*
* @param mimeType the mime type for which a content handler should be returned.
* @return a content handler proxy for the specified mime type.
**/
public ContentHandler createContentHandler(String mimeType)
{
// See if there is a cached stream handler.
// IMPLEMENTATION NOTE: Caching is not strictly necessary for
// stream handlers since the Java runtime caches them. Caching is
// performed for code consistency between stream and content
// handlers and also because caching behavior may not be guaranteed
// across different JRE implementations.
ContentHandler handler = getFromContentCache(mimeType);
if (handler != null)
{
return handler;
}
return addToContentCache(mimeType,
new URLHandlersContentHandlerProxy(mimeType, m_secureAction,
(m_contentHandlerFactory != this) ? m_contentHandlerFactory : null));
}
private synchronized ContentHandler addToContentCache(String mimeType, ContentHandler handler)
{
if (m_contentHandlerCache == null)
{
m_contentHandlerCache = new HashMap();
}
return (ContentHandler) addToCache(m_contentHandlerCache, mimeType, handler);
}
private synchronized ContentHandler getFromContentCache(String mimeType)
{
return (ContentHandler) ((m_contentHandlerCache != null) ?
m_contentHandlerCache.get(mimeType) : null);
}
private synchronized URLStreamHandler addToStreamCache(String protocol, URLStreamHandler handler)
{
if (m_streamHandlerCache == null)
{
m_streamHandlerCache = new HashMap();
}
return (URLStreamHandler) addToCache(m_streamHandlerCache, protocol, handler);
}
private synchronized URLStreamHandler getFromStreamCache(String protocol)
{
return (URLStreamHandler) ((m_streamHandlerCache != null) ?
m_streamHandlerCache.get(protocol) : null);
}
private Object addToCache(Map cache, String key, Object value)
{
if (value == null)
{
return null;
}
Object result = cache.get(key);
if (result == null)
{
cache.put(key, value);
result = value;
}
return result;
}
/**
*
* Static method that adds a framework instance to the centralized
* instance registry.
*
* @param framework the framework instance to be added to the instance
* registry.
* @param enable a flag indicating whether or not the framework wants to
* enable the URL Handlers service.
**/
public static void registerFrameworkInstance(Object framework, boolean enable)
{
boolean register = false;
synchronized (m_frameworks)
{
// If the URL Handlers service is not going to be enabled,
// then return immediately.
if (enable)
{
// We need to create an instance if this is the first
// time this method is called, which will set the handler
// factories.
if (m_handler == null )
{
register = true;
}
else
{
m_frameworks.add(framework);
m_counter++;
}
}
else
{
m_counter++;
}
}
if (register)
{
synchronized (URL.class)
{
synchronized (m_classloaderToFrameworkLists)
{
synchronized (m_frameworks)
{
if (m_handler == null )
{
m_handler = new URLHandlers();
}
m_frameworks.add(framework);
m_counter++;
}
}
}
}
}
/**
*
* Static method that removes a framework instance from the centralized
* instance registry.
*
* @param framework the framework instance to be removed from the instance
* registry.
**/
public static void unregisterFrameworkInstance(Object framework)
{
boolean unregister = false;
synchronized (m_frameworks)
{
if (m_frameworks.contains(framework))
{
if (m_frameworks.size() == 1 && m_handler != null)
{
unregister = true;
}
else
{
m_frameworks.remove(framework);
m_counter--;
}
}
else
{
m_counter--;
}
}
if (unregister)
{
synchronized (URL.class)
{
synchronized (m_classloaderToFrameworkLists)
{
synchronized (m_frameworks)
{
m_frameworks.remove(framework);
m_counter--;
if (m_frameworks.isEmpty() && m_handler != null)
{
m_handler = null;
try
{
m_secureAction.invoke(m_secureAction.getDeclaredMethod(
m_rootURLHandlers.getClass(),
"unregisterFrameworkListsForContextSearch",
new Class[]{ ClassLoader.class}),
m_rootURLHandlers,
new Object[] {URLHANDLERS_CLASS.getClassLoader()});
}
catch (Exception e)
{
// This should not happen
e.printStackTrace();
}
}
}
}
}
}
}
/**
*
* This method returns the system bundle context for the caller.
* It determines the appropriate system bundle by retrieving the
* class call stack and find the first class that is loaded from
* a bundle. It then checks to see which of the registered framework
* instances owns the class and returns its system bundle context.
*
* @return the system bundle context associated with the caller or
* null if no associated framework was found.
**/
public static Object getFrameworkFromContext()
{
// This is a hack. The idea is to return the only registered framework
synchronized (m_classloaderToFrameworkLists)
{
if (m_classloaderToFrameworkLists.isEmpty())
{
synchronized (m_frameworks)
{
if ((m_counter == 1) && (m_frameworks.size() == 1))
{
return m_frameworks.get(0);
}
}
}
}
// get the current class call stack.
Class[] stack = m_sm.getClassContext();
// Find the first class that is loaded from a bundle.
Class targetClass = null;
for (int i = 0; i < stack.length; i++)
{
if (stack[i].getClassLoader() != null)
{
String name = stack[i].getClassLoader().getClass().getName();
if (name.startsWith("org.apache.felix.framework.ModuleImpl$ModuleClassLoader")
|| name.equals("org.apache.felix.framework.searchpolicy.ContentClassLoader")
|| name.startsWith("org.apache.felix.framework.BundleWiringImpl$BundleClassLoader"))
{
targetClass = stack[i];
break;
}
}
}
// If we found a class loaded from a bundle, then iterate
// over the framework instances and see which framework owns
// the bundle that loaded the class.
if (targetClass != null)
{
synchronized (m_classloaderToFrameworkLists)
{
ClassLoader index = targetClass.getClassLoader().getClass().getClassLoader();
List frameworks = (List) m_classloaderToFrameworkLists.get(
index);
if ((frameworks == null) && (index == URLHANDLERS_CLASS.getClassLoader()))
{
frameworks = m_frameworks;
}
if (frameworks != null)
{
synchronized (frameworks)
{
// Check the registry of framework instances
for (int i = 0; i < frameworks.size(); i++)
{
Object framework = frameworks.get(i);
try
{
if (m_secureAction.invoke(
m_secureAction.getDeclaredMethod(framework.getClass(),
"getBundle", CLASS_TYPE),
framework, new Object[]{targetClass}) != null)
{
return framework;
}
}
catch (Exception ex)
{
// This should not happen but if it does there is
// not much we can do other then ignore it.
// Maybe log this or something.
ex.printStackTrace();
}
}
}
}
}
}
return null;
}
}
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