/*
* JARClassLoader.java - Loads classes from JAR files
* :tabSize=4:indentSize=4:noTabs=false:
* :folding=explicit:collapseFolds=1:
*
* Copyright (C) 1999, 2003 Slava Pestov
* Portions copyright (C) 1999 mike dillon
*
* 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 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.
*/
package org.gjt.sp.jedit;
//{{{ Imports
import java.io.InputStream;
import java.io.IOException;
import java.net.URL;
import java.util.*;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import org.gjt.sp.util.Log;
import java.util.jar.Manifest;
import java.util.jar.JarFile;
import java.net.MalformedURLException;
import java.util.jar.Attributes;
import java.util.jar.Attributes.Name;
//}}}
/**
* A class loader implementation that loads classes from JAR files. All
* instances share the same set of classes.
* @author Slava Pestov
* @version $Id: JARClassLoader.java 23224 2013-09-30 20:51:42Z shlomy $
*/
public class JARClassLoader extends ClassLoader
{
//{{{ JARClassLoader constructor
/**
* This constructor creates a class loader for loading classes from all
* plugins. For example BeanShell uses one of these so that scripts can
* use plugin classes.
*/
public JARClassLoader()
{
this(true);
}
/**
* Creates a class loader that will optionally delegate the
* finding of classes to the parent class loader by default.
*
* @since jEdit 4.3pre6
*/
public JARClassLoader(boolean delegateFirst)
{
this.delegateFirst = delegateFirst;
// for debugging
id = INDEX++;
live++;
} //}}}
//{{{ loadClass() method
/**
* @exception ClassNotFoundException if the class could not be found
*/
public Class loadClass(String clazz, boolean resolveIt)
throws ClassNotFoundException
{
ClassNotFoundException pending = null;
if (delegateFirst)
{
try
{
return loadFromParent(clazz);
}
catch (ClassNotFoundException cnf)
{
// keep going if class was not found.
pending = cnf;
}
}
Object obj = classHash.get(clazz);
if(obj == NO_CLASS)
{
// we remember which classes we don't exist
// because BeanShell tries loading all possible
// <imported prefix>.<class name> combinations
throw new ClassNotFoundException(clazz);
}
else if(obj instanceof JARClassLoader)
{
JARClassLoader classLoader = (JARClassLoader)obj;
try
{
return classLoader._loadClass(clazz,resolveIt);
} catch (ClassNotFoundException cnf2)
{
classHash.put(clazz,NO_CLASS);
throw cnf2;
}
}
else if (delegateFirst)
{
// if delegating, reaching this statement means
// the class was really not found. Otherwise
// we'll try loading from the parent class loader.
throw pending;
}
return loadFromParent(clazz);
} //}}}
//{{{ getResourceAsStream() method
public InputStream getResourceAsStream(String name)
{
try
{
// try in current jar first
if(jar != null)
{
ZipFile zipFile = jar.getZipFile();
ZipEntry entry = zipFile.getEntry(name);
if(entry != null)
{
return zipFile.getInputStream(entry);
}
}
// then try from another jar
Object obj = resourcesHash.get(name);
if(obj instanceof JARClassLoader)
{
JARClassLoader classLoader = (JARClassLoader)obj;
return classLoader.getResourceAsStream(name);
}
// finally try from the system class loader
return getSystemResourceAsStream(name);
}
catch(IOException io)
{
Log.log(Log.ERROR,this,io);
return null;
}
} //}}}
//{{{ getResource() method
/**
* overriding getResource() because we want to search FIRST in this
* ClassLoader, then the parent, the path, etc.
*/
public URL getResource(String name)
{
try
{
if(jar != null)
{
ZipFile zipFile = jar.getZipFile();
ZipEntry entry = zipFile.getEntry(name);
if(entry != null)
{
return new URL(getResourceAsPath(name));
}
}
Object obj = resourcesHash.get(name);
if(obj instanceof JARClassLoader)
{
JARClassLoader classLoader = (JARClassLoader)obj;
return classLoader.getResource(name);
} else
{
URL ret = getSystemResource(name);
if(ret != null)
{
Log.log(Log.DEBUG,JARClassLoader.class,"Would have returned null for getResource("+name+")");
Log.log(Log.DEBUG,JARClassLoader.class,"returning("+ret+")");
}
return ret;
}
}
catch(IOException io)
{
Log.log(Log.ERROR,this,io);
return null;
}
} //}}}
//{{{ getResourceAsPath() method
/**
* construct a jeditresource:/etc path from the name
* of a resource in the associated jar.
* The existence of the resource is not actually checked.
*
* @param name name of the resource
* @return jeditresource:/path_to_the_jar!name_of_the_resource
* @throws UnsupportedOperationException if this is an anonymous
* JARClassLoader (no associated jar).
*/
public String getResourceAsPath(String name)
{
// this must be fixed during plugin development
if(jar == null)
throw new UnsupportedOperationException(
"don't call getResourceAsPath() on anonymous JARClassLoader");
if(!name.startsWith("/"))
name = '/' + name;
return "jeditresource:/" + MiscUtilities.getFileName(
jar.getPath()) + '!' + name;
} //}}}
//{{{ dump() method
/**
* For debugging.
*/
public static void dump()
{
Log.log(Log.DEBUG,JARClassLoader.class,
"Total instances created: " + INDEX);
Log.log(Log.DEBUG,JARClassLoader.class,
"Live instances: " + live);
synchronized(classHash)
{
for (Map.Entry<String, Object> entry : classHash.entrySet())
{
if (entry.getValue() != NO_CLASS)
{
Log.log(Log.DEBUG, JARClassLoader.class,
entry.getKey() + " ==> "
+ entry.getValue());
}
}
}
} //}}}
//{{{ toString() method
public String toString()
{
if(jar == null)
return "<anonymous>(" + id + ')';
else
return jar.getPath() + " (" + id + ')';
} //}}}
//{{{ findResources() method
/**
* @return zero or one resource, as returned by getResource()
*/
public Enumeration getResources(String name) throws IOException
{
class SingleElementEnumeration implements Enumeration
{
private Object element;
SingleElementEnumeration(Object element)
{
this.element = element;
}
public boolean hasMoreElements()
{
return element != null;
}
public Object nextElement()
{
if(element != null)
{
Object retval = element;
element = null;
return retval;
}
else
throw new NoSuchElementException();
}
}
URL resource = getResource(name);
return new SingleElementEnumeration(resource);
} //}}}
//{{{ finalize() method
protected void finalize()
{
live--;
} //}}}
//{{{ Package-private members
//{{{ JARClassLoader constructor
/**
* @since jEdit 4.2pre1
*/
JARClassLoader(PluginJAR jar)
{
this();
this.jar = jar;
} //}}}
//{{{ activate() method
void activate()
{
if (jar.getPlugin() != null)
{
String _delegate = jEdit.getProperty(
"plugin." + jar.getPlugin().getClassName() + ".class_loader_delegate");
delegateFirst = _delegate == null || "true".equals(_delegate);
}
String[] classes = jar.getClasses();
if(classes != null)
{
for (String aClass : classes)
classHash.put(aClass, this);
}
String[] resources = jar.getResources();
if(resources != null)
{
for (String resource : resources)
resourcesHash.put(resource, this);
}
} //}}}
//{{{ deactivate() method
void deactivate()
{
String[] classes = jar.getClasses();
if(classes != null)
{
for (String aClass : classes)
{
Object loader = classHash.get(aClass);
if (loader == this)
classHash.remove(aClass);
else
/* two plugins provide same class! */;
}
}
String[] resources = jar.getResources();
if(resources == null)
return;
for (String resource : resources)
{
Object loader = resourcesHash.get(resource);
if (loader == this)
resourcesHash.remove(resource);
else
/* two plugins provide same resource! */;
}
} //}}}
//}}}
//{{{ Private members
// used to mark non-existent classes in class hash
private static final Object NO_CLASS = new Object();
private static int INDEX;
private static int live;
private static Map<String, Object> classHash = new Hashtable<String, Object>();
private static Map<String, Object> resourcesHash = new HashMap<String, Object>();
private int id;
private boolean delegateFirst;
private PluginJAR jar;
//{{{ _loadClass() method
/**
* Load class from this JAR only.
*/
private synchronized Class _loadClass(String clazz, boolean resolveIt)
throws ClassNotFoundException
{
jar.activatePlugin();
synchronized(this)
{
Class cls = findLoadedClass(clazz);
if(cls != null)
{
if(resolveIt)
resolveClass(cls);
return cls;
}
String name = MiscUtilities.classToFile(clazz);
try
{
definePackage(clazz);
ZipFile zipFile = jar.getZipFile();
ZipEntry entry = zipFile.getEntry(name);
if(entry == null)
throw new ClassNotFoundException(clazz);
InputStream in = zipFile.getInputStream(entry);
int len = (int)entry.getSize();
byte[] data = new byte[len];
int success = 0;
int offset = 0;
while(success < len)
{
len -= success;
offset += success;
success = in.read(data,offset,len);
if(success == -1)
{
Log.log(Log.ERROR,this,"Failed to load class "
+ clazz + " from " + zipFile.getName());
throw new ClassNotFoundException(clazz);
}
}
cls = defineClass(clazz,data,0,data.length);
if(resolveIt)
resolveClass(cls);
return cls;
}
catch(IOException io)
{
Log.log(Log.ERROR,this,io);
throw new ClassNotFoundException(clazz);
}
}
} //}}}
//{{{ definePackage(clazz) method
private void definePackage(String clazz) throws IOException
{
int idx = clazz.lastIndexOf('.');
if (idx != -1)
{
String name = clazz.substring(0, idx);
if (getPackage(name) == null) definePackage(name, new JarFile(jar.getFile()).getManifest());
}
} //}}}
//{{{ getMfValue() method
private static String getMfValue(Attributes sectionAttrs, Attributes mainAttrs, Attributes.Name name)
{
String value=null;
if (sectionAttrs != null)
value = sectionAttrs.getValue(name);
else if (mainAttrs != null)
{
value = mainAttrs.getValue(name);
}
return value;
}
//}}}
//{{{ definePackage(packageName, manifest) method
private void definePackage(String name, Manifest mf)
{
if (mf==null)
{
definePackage(name, null, null, null, null, null,
null, null);
return;
}
Attributes sa = mf.getAttributes(name.replace('.', '/') + '/');
Attributes ma = mf.getMainAttributes();
URL sealBase = null;
if (Boolean.valueOf(getMfValue(sa, ma, Name.SEALED)).booleanValue())
{
try
{
sealBase = jar.getFile().toURL();
}
catch (MalformedURLException e) {}
}
definePackage(
name,
getMfValue(sa, ma, Name.SPECIFICATION_TITLE),
getMfValue(sa, ma, Name.SPECIFICATION_VERSION),
getMfValue(sa, ma, Name.SPECIFICATION_VENDOR),
getMfValue(sa, ma, Name.IMPLEMENTATION_TITLE),
getMfValue(sa, ma, Name.IMPLEMENTATION_VERSION),
getMfValue(sa, ma, Name.IMPLEMENTATION_VENDOR),
sealBase);
} //}}}
//{{{ loadFromParent() method
private Class loadFromParent(String clazz)
throws ClassNotFoundException
{
Class cls;
ClassLoader parentLoader = getClass().getClassLoader();
if (parentLoader != null)
cls = parentLoader.loadClass(clazz);
else
cls = findSystemClass(clazz);
return cls;
} //}}}
//}}}
}