namespacesymbtable.java

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/*
 * Copyright  1999-2004 The Apache Software Foundation.
 *
 *  Licensed 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 com.sun.org.apache.xml.internal.security.c14n.implementations;

import java.lang.reflect.Array;
import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;



import org.w3c.dom.Attr;
import org.w3c.dom.Node;



/**
 * A stack based Symble Table.
 *<br>For speed reasons all the symbols are introduced in the same map,
 * and at the same time in a list so it can be removed when the frame is pop back.
 * @author Raul Benito
 **/
public class NameSpaceSymbTable {
	
	/**The map betwen prefix-> entry table. */
	SymbMap symb = new SymbMap();
	/**The level of nameSpaces (for Inclusive visibility).*/
	int nameSpaces=0;
	/**The stacks for removing the definitions when doing pop.*/
	List level = new ArrayList();
    boolean cloned=true;	
	static final String XMLNS="xmlns";
    /**
     * Default constractor
     **/		
    public NameSpaceSymbTable() {
    	//Insert the default binding for xmlns.
    	NameSpaceSymbEntry ne=new NameSpaceSymbEntry("",null,true);
		ne.lastrendered="";
    	symb.put(XMLNS,ne);    
    }
    
    /**
	 * Get all the unrendered nodes in the name space.
	 * For Inclusive rendering
     * @param result the list where to fill the unrendered xmlns definitions.
	 **/       
	public  void getUnrenderedNodes(Collection result) {		
	   //List result=new ArrayList();
	   Iterator it=symb.entrySet().iterator();
	   while (it.hasNext()) {	   	   
	   		NameSpaceSymbEntry n=(NameSpaceSymbEntry)(it.next());
	   		//put them rendered?
	   		if ((!n.rendered) && (n.n!=null)) {
	   			result.add(n.n);
	   			n.rendered=true;
	   		}
	   }	   
	}
	
	/**
     * Push a frame for visible namespace. 
     * For Inclusive rendering.
     **/
	public void outputNodePush() {
		nameSpaces++;
		push();
	}
	
	/**
     * Pop a frame for visible namespace.
     **/
	public void outputNodePop() {
		nameSpaces--;
		pop();
	}
	
	/**
     * Push a frame for a node.
     * Inclusive or Exclusive.
     **/
	public void push() {		
		//Put the number of namespace definitions in the stack.
        /**if (cloned) {
        	Object ob[]= {symb,cloned ? symb : null};
        	level.add(ob);
        } **/
        level.add(null);
        cloned=false;
	}
	
	/**
     * Pop a frame.
     * Inclusive or Exclusive.
     **/
	public void pop() {
        int size=level.size()-1;
        Object ob= level.remove(size);
        if (ob!=null) {
        	symb=(SymbMap)ob;
            if (size==0) {
               cloned=false;   
            } else
            cloned=(level.get(size-1)!=symb);
        } else {
        	cloned=false;
        }
        
        
	}
	
	final void needsClone() {
		if (!cloned) {
            level.remove(level.size()-1);
            level.add(symb);
			symb=(SymbMap) symb.clone();
            cloned=true;
        }
    }
	
	
	/**
	 * Gets the attribute node that defines the binding for the prefix.      
     * @param prefix the prefix to obtain the attribute.
     * @return null if there is no need to render the prefix. Otherwise the node of
     * definition.
     **/
	public Attr getMapping(String prefix) {					
		NameSpaceSymbEntry entry=symb.get(prefix);
		if (entry==null) {
			//There is no definition for the prefix(a bug?).
			return null;
		}
		if (entry.rendered) {		
			//No need to render an entry already rendered.
			return null;		
		}
		// Mark this entry as render.
        entry=(NameSpaceSymbEntry) entry.clone();
        needsClone();
        symb.put(prefix,entry);
		entry.rendered=true;
		entry.level=nameSpaces;
		entry.lastrendered=entry.uri;				
		// Return the node for outputing.
		return entry.n;
	}
	
	/**
     * Gets a definition without mark it as render. 
     * For render in exclusive c14n the namespaces in the include prefixes.
     * @param prefix The prefix whose definition is neaded.
     * @return the attr to render, null if there is no need to render
     **/
	public Attr getMappingWithoutRendered(String prefix) {					
		NameSpaceSymbEntry entry= symb.get(prefix);
		if (entry==null) {		   
			return null;
		}
		if (entry.rendered) {		
			return null;		
		}
		return entry.n;
	}
	
	/**
     * Adds the mapping for a prefix.
     * @param prefix the prefix of definition
     * @param uri the Uri of the definition
     * @param n the attribute that have the definition
     * @return true if there is already defined.
     **/
	public boolean addMapping(String prefix, String uri,Attr n) {						
		NameSpaceSymbEntry ob = symb.get(prefix);		
		if ((ob!=null) && uri.equals(ob.uri)) {
			//If we have it previously defined. Don't keep working.
			return false;
		}			
		//Creates and entry in the table for this new definition.
		NameSpaceSymbEntry ne=new NameSpaceSymbEntry(uri,n,false);		
        needsClone();
		symb.put(prefix, ne);
		if (ob != null) {
			//We have a previous definition store it for the pop.			
			//Check if a previous definition(not the inmidiatly one) has been rendered.			
			ne.lastrendered=ob.lastrendered;			
			if ((ob.lastrendered!=null)&& (ob.lastrendered.equals(uri))) {
				//Yes it is. Mark as rendered.
				ne.rendered=true;
			}			
		} 			
        return true;
	}

    /**
     * Adds a definition and mark it as render.
     * For inclusive c14n.
     * @param prefix the prefix of definition
     * @param uri the Uri of the definition
     * @param n the attribute that have the definition
     * @return the attr to render, null if there is no need to render
     **/
    public Node addMappingAndRender(String prefix, String uri,Attr n) {                     
        NameSpaceSymbEntry ob = symb.get(prefix);
        
        if ((ob!=null) && uri.equals(ob.uri)) {
            if (!ob.rendered) {                 
                ob=(NameSpaceSymbEntry) ob.clone();
                needsClone();
                symb.put(prefix,ob);         
                ob.lastrendered=uri;
                ob.rendered=true;
                return ob.n;
            }           
            return null;
        }   
        
        NameSpaceSymbEntry ne=new NameSpaceSymbEntry(uri,n,true);
        ne.lastrendered=uri;
        needsClone();
        symb.put(prefix, ne);
        if (ob != null) {           
            
            if ((ob.lastrendered!=null)&& (ob.lastrendered.equals(uri))) {
                ne.rendered=true;
                return null;
            }
        }       
        return ne.n;
    }
	/** 
     * Adds & gets(if needed) the attribute node that defines the binding for the prefix. 
     * Take on account if the rules of rendering in the inclusive c14n.
     * For inclusive c14n.
     * @param prefix the prefix to obtain the attribute.
     * @param outputNode the container element is an output element.
     * @param uri the Uri of the definition
     * @param n the attribute that have the definition
     * @return null if there is no need to render the prefix. Otherwise the node of
     * definition.     
     **/
	public Node addMappingAndRenderXNodeSet(String prefix, String uri,Attr n,boolean outputNode) {						
		NameSpaceSymbEntry ob = symb.get(prefix);
		int visibleNameSpaces=nameSpaces;		
		if ((ob!=null) && uri.equals(ob.uri)) {
			if (!ob.rendered) {					
				ob=(NameSpaceSymbEntry)ob.clone();
                needsClone();
                symb.put(prefix,ob);				
				ob.rendered=true;
				ob.level=visibleNameSpaces;
				return ob.n;
			}						
            ob=(NameSpaceSymbEntry)ob.clone();
            needsClone();
            symb.put(prefix,ob);
			if (outputNode && (((visibleNameSpaces-ob.level)<2) || XMLNS.equals(prefix)) ) {
				ob.level=visibleNameSpaces;
				return null; //Already rendered, just return nulll
			}
			ob.level=visibleNameSpaces;
			return ob.n;
		}	
		
		NameSpaceSymbEntry ne=new NameSpaceSymbEntry(uri,n,true);
		ne.level=nameSpaces;
		ne.rendered=true;
        needsClone();
		symb.put(prefix, ne);
		if (ob != null) {			
			ne.lastrendered=ob.lastrendered;
			
			if ((ob.lastrendered!=null)&& (ob.lastrendered.equals(uri))) {
				ne.rendered=true;
			}
		}	
		return ne.n;
	}
}

/**
 * The internal structure of NameSpaceSymbTable.
 **/
class NameSpaceSymbEntry implements Cloneable {
    NameSpaceSymbEntry(String name,Attr n,boolean rendered) {
        this.uri=name;          
        this.rendered=rendered;
        this.n=n;            
    }
    /** @inheritDoc */
    public Object clone() {         
        try {
            return super.clone();
        } catch (CloneNotSupportedException e) {
            return null;
        }
    }
    /** The level where the definition was rendered(Only for inclusive) */
    int level=0;
    /**The URI that the prefix defines */
    String uri;
    /**The last output in the URI for this prefix (This for speed reason).*/
    String lastrendered=null;
    /**This prefix-URI has been already render or not.*/
    boolean rendered=false;
    /**The attribute to include.*/
    Attr n;        
};

class SymbMap implements Cloneable{	
	int free=23;
	NameSpaceSymbEntry[] entries=new NameSpaceSymbEntry[free];
	String[] keys=new String[free];
	
	void put(String key, NameSpaceSymbEntry value) {		
        int index = index(key);
		Object oldKey = keys[index];
		keys[index] = key;
		entries[index] = value;
        if (oldKey==null || !oldKey.equals(key)) {	        	        
	        if (--free == 0) {
				free=entries.length;
	            int newCapacity = free<<2;				
	            rehash(newCapacity);			
	        }
        }
    }
	
    List entrySet() {
		List a=new ArrayList();
		for (int i=0;i<entries.length;i++) {
			if ((entries[i]!=null) && !("".equals(entries[i]))) {
				a.add(entries[i]);
			}
		}
		return a;		
	}


	protected int index(Object obj) {		
        Object[] set = keys;
		int length = set.length;
		//abs of index
        int index = (obj.hashCode() & 0x7fffffff) %  length;
        Object cur = set[index];

        if (cur == null || (cur.equals( obj))) {
			return index;
        }
        do {
			index=index==length? 0:++index;
			cur = set[index];
        } while (cur != null && (!cur.equals(obj)));       
        return index;
    }
	 /**
     * rehashes the map to the new capacity.
     *
     * @param newCapacity an <code>int</code> value
     */
    protected void rehash(int newCapacity) {
        int oldCapacity = keys.length;
        String oldKeys[] = keys;
		NameSpaceSymbEntry oldVals[] = entries;

		keys = new String[newCapacity];        
		entries = new NameSpaceSymbEntry[newCapacity];

        for (int i = oldCapacity; i-- > 0;) {
            if(oldKeys[i] != null) {
                String o = oldKeys[i];
                int index = index(o);
				keys[index] = o;
				entries[index] = oldVals[i];
            }
        }
    }
	 NameSpaceSymbEntry get(String key) {
	        return  entries[index(key)];
	    }
	 protected Object clone()  {
		// TODO Auto-generated method stub
		try {
			SymbMap copy=(SymbMap) super.clone();
			copy.entries=new NameSpaceSymbEntry[entries.length];
			System.arraycopy(entries,0,copy.entries,0,entries.length);
			copy.keys=new String[keys.length];
			System.arraycopy(keys,0,copy.keys,0,keys.length);
			
			return copy;
		} catch (CloneNotSupportedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
		return null;
	}
}