/***** BEGIN LICENSE BLOCK *****
* Version: CPL 1.0/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Common 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/cpl-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) 2005 Thomas E. Enebo <enebo@acm.org>
*
* 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"),
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package org.jruby.runtime;
import java.util.WeakHashMap;
import java.util.Iterator;
import java.util.Map;
import org.jruby.Ruby;
import org.jruby.RubyModule;
import org.jruby.internal.runtime.methods.DynamicMethod;
import org.jruby.util.WeakIdentityHashMap;
/**
* This class represents mappings between methods that have been cached and the classes which
* have cached them. Methods within RubyModule will update this cacheMap as needed. Here is
* a list of scenarios when cached methods will become invalid:
*
* 1. Redefine a method in a base class
* 2. Add an alias in a superclass that is the same name as a cached method in a base class
* 3. Include a module that has a same-named method as one already caches in a base class
* 4. Remove a method definition
* 5. Add a same-named method in super class that has been cached in a super class
*
* Concurrency is another concern with managing this structure. Rather than synchronize this
* we are going to rely on synchronization further upstream. RubyModule methods that directly
* call this is responsible for synchronization.
*/
public class CacheMap {
private final Map mappings = new WeakHashMap();
private final Ruby runtime;
public CacheMap(Ruby runtime) {
this.runtime = runtime;
}
/**
* Add another class to the list of classes which are caching the method.
*
* @param method which is cached
* @param module which is caching method
*/
public void add(DynamicMethod method, RubyModule module) {
Map classList = (Map) mappings.get(method);
if (classList == null) {
classList = new WeakIdentityHashMap();
mappings.put(method, classList);
}
classList.put(module,null);
}
/**
* Remove all method caches associated with the provided method. This signature
* relies on having the methods valid name passed with it since the caching classes
* store the cache by name.
*
* @param name of the method to remove
* @param method to remove all caches of
*/
public void remove(String name, DynamicMethod method) {
Map classList = (Map) mappings.remove(method);
// Removed method has never been used so it has not been cached
if (classList == null) {
return;
}
for(Iterator iter = classList.keySet().iterator(); iter.hasNext();) {
RubyModule module = (RubyModule) iter.next();
if (module != null) {
module.removeCachedMethod(name);
if (module.index != 0) {
runtime.getSelectorTable().table[module.index][MethodIndex.getIndex(name)] = 0;
}
}
}
}
}
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