xsdfacm.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.xerces.internal.impl.xs.models;

import com.sun.org.apache.xerces.internal.xni.QName;
import com.sun.org.apache.xerces.internal.impl.dtd.models.CMNode;
import com.sun.org.apache.xerces.internal.impl.dtd.models.CMStateSet;
import com.sun.org.apache.xerces.internal.impl.xs.SubstitutionGroupHandler;
import com.sun.org.apache.xerces.internal.impl.xs.XSElementDecl;
import com.sun.org.apache.xerces.internal.impl.xs.XSParticleDecl;
import com.sun.org.apache.xerces.internal.impl.xs.XSModelGroupImpl;
import com.sun.org.apache.xerces.internal.impl.xs.XSWildcardDecl;
import com.sun.org.apache.xerces.internal.impl.xs.XMLSchemaException;
import com.sun.org.apache.xerces.internal.impl.xs.XSConstraints;

import java.util.Vector;

/**
 * DFAContentModel is the implementation of XSCMValidator that does
 * all of the non-trivial element content validation. This class does
 * the conversion from the regular expression to the DFA that
 * it then uses in its validation algorithm.
 *
 * @xerces.internal 
 *
 * @author Neil Graham, IBM
 * @version $Id: XSDFACM.java,v 1.4 2006/07/19 22:39:36 spericas Exp $
 */
public class XSDFACM
    implements XSCMValidator {

    //
    // Constants
    //
    private static final boolean DEBUG = false;

    // special strings

    // debugging

    /** Set to true to debug content model validation. */
    private static final boolean DEBUG_VALIDATE_CONTENT = false;

    //
    // Data
    //

    /**
     * This is the map of unique input symbol elements to indices into
     * each state's per-input symbol transition table entry. This is part
     * of the built DFA information that must be kept around to do the
     * actual validation.  Note tat since either XSElementDecl or XSParticleDecl object
     * can live here, we've got to use an Object.
     */
    private Object fElemMap[] = null;

    /**
     * This is a map of whether the element map contains information
     * related to ANY models.
     */
    private int fElemMapType[] = null;

    /**
     * id of the unique input symbol
     */
    private int fElemMapId[] = null;
    
    /** The element map size. */
    private int fElemMapSize = 0;

    /**
     * This is an array of booleans, one per state (there are
     * fTransTableSize states in the DFA) that indicates whether that
     * state is a final state.
     */
    private boolean fFinalStateFlags[] = null;

    /**
     * The list of follow positions for each NFA position (i.e. for each
     * non-epsilon leaf node.) This is only used during the building of
     * the DFA, and is let go afterwards.
     */
    private CMStateSet fFollowList[] = null;

    /**
     * This is the head node of our intermediate representation. It is
     * only non-null during the building of the DFA (just so that it
     * does not have to be passed all around.) Once the DFA is built,
     * this is no longer required so its nulled out.
     */
    private CMNode fHeadNode = null;

    /**
     * The count of leaf nodes. This is an important number that set some
     * limits on the sizes of data structures in the DFA process.
     */
    private int fLeafCount = 0;

    /**
     * An array of non-epsilon leaf nodes, which is used during the DFA
     * build operation, then dropped.
     */
    private XSCMLeaf fLeafList[] = null;

    /** Array mapping ANY types to the leaf list. */
    private int fLeafListType[] = null;

    /**
     * This is the transition table that is the main by product of all
     * of the effort here. It is an array of arrays of ints. The first
     * dimension is the number of states we end up with in the DFA. The
     * second dimensions is the number of unique elements in the content
     * model (fElemMapSize). Each entry in the second dimension indicates
     * the new state given that input for the first dimension's start
     * state.
     * <p>
     * The fElemMap array handles mapping from element indexes to
     * positions in the second dimension of the transition table.
     */
    private int fTransTable[][] = null;

    /**
     * The number of valid entries in the transition table, and in the other
     * related tables such as fFinalStateFlags.
     */
    private int fTransTableSize = 0;
    
    private int fOneTransitionCounter = 0;
    
    private Object fUserData;

    // temp variables

    //
    // Constructors
    //

    /**
     * Constructs a DFA content model.
     *
     * @param syntaxTree    The syntax tree of the content model.
     * @param leafCount     The number of leaves.
     *
     * @exception RuntimeException Thrown if DFA can't be built.
     */

   public XSDFACM(CMNode syntaxTree, int leafCount) {
   
        // Store away our index and pools in members
        fLeafCount = leafCount;
        
        fUserData = syntaxTree.getUserData();

        //
        //  Create some string pool indexes that represent the names of some
        //  magical nodes in the syntax tree.
        //  (already done in static initialization...
        //

        //
        //  Ok, so lets grind through the building of the DFA. This method
        //  handles the high level logic of the algorithm, but it uses a
        //  number of helper classes to do its thing.
        //
        //  In order to avoid having hundreds of references to the error and
        //  string handlers around, this guy and all of his helper classes
        //  just throw a simple exception and we then pass it along.
        //

        if(DEBUG_VALIDATE_CONTENT) {
            XSDFACM.time -= System.currentTimeMillis();
        }

        buildDFA(syntaxTree);

        if(DEBUG_VALIDATE_CONTENT) {
            XSDFACM.time += System.currentTimeMillis();
            System.out.println("DFA build: " + XSDFACM.time + "ms");
        }
    }

    private static long time = 0;

    //
    // XSCMValidator methods
    //
    
    /**
     * Return the number of times the <code>oneTransition()</code> method 
     * was called, resulting on the DFA to move into a non-error state. 
     * This is used to check the minOccurs and maxOccurs bounds using a 
     * constant space algorithm.
     */ 
    public int getOneTransitionCounter() {
        return fOneTransitionCounter;
    }
    
    /**
     * Allows the user to get arbitrary data originally set on the content 
     * model node used to create this DFA.
     */
    public Object getUserData() {
        return fUserData;
    }

    /**
     * check whether the given state is one of the final states
     *
     * @param state       the state to check
     *
     * @return whether it's a final state
     */
    public boolean isFinalState (int state) {
        return (state < 0)? false :
            fFinalStateFlags[state];
    }

    /**
     * one transition only
     *
     * @param curElem The current element's QName
     * @param state stack to store the previous state
     * @param subGroupHandler the substitution group handler
     *
     * @return  null if transition is invalid; otherwise the Object corresponding to the
     *      XSElementDecl or XSWildcardDecl identified.  Also, the
     *      state array will be modified to include the new state; this so that the validator can
     *      store it away.
     *
     * @exception RuntimeException thrown on error
     */
    public Object oneTransition(QName curElem, int[] state, SubstitutionGroupHandler subGroupHandler) {
        int curState = state[0];

        if(curState == XSCMValidator.FIRST_ERROR || curState == XSCMValidator.SUBSEQUENT_ERROR) {
            // there was an error last time; so just go find correct Object in fElemmMap.
            // ... after resetting state[0].
            if(curState == XSCMValidator.FIRST_ERROR)
                state[0] = XSCMValidator.SUBSEQUENT_ERROR;

            return findMatchingDecl(curElem, subGroupHandler);
        }

        int nextState = 0;
        int elemIndex = 0;
        Object matchingDecl = null;

        for (; elemIndex < fElemMapSize; elemIndex++) {
            nextState = fTransTable[curState][elemIndex];
            if (nextState == -1)
                continue;
            int type = fElemMapType[elemIndex] ;
            if (type == XSParticleDecl.PARTICLE_ELEMENT) {
                matchingDecl = subGroupHandler.getMatchingElemDecl(curElem, (XSElementDecl)fElemMap[elemIndex]);
                if (matchingDecl != null) {
                    break;
                }
            }
            else if (type == XSParticleDecl.PARTICLE_WILDCARD) {
                if(((XSWildcardDecl)fElemMap[elemIndex]).allowNamespace(curElem.uri)) {
                    matchingDecl = fElemMap[elemIndex];
                    break;
                }
            }
        }

        // if we still can't find a match, set the state to first_error
        // and return null
        if (elemIndex == fElemMapSize) {
            state[1] = state[0];
            state[0] = XSCMValidator.FIRST_ERROR;
            return findMatchingDecl(curElem, subGroupHandler);
        }

        fOneTransitionCounter++;
        state[0] = nextState;
        return matchingDecl;
    } // oneTransition(QName, int[], SubstitutionGroupHandler):  Object

    Object findMatchingDecl(QName curElem, SubstitutionGroupHandler subGroupHandler) {
        Object matchingDecl = null;

        for (int elemIndex = 0; elemIndex < fElemMapSize; elemIndex++) {
            int type = fElemMapType[elemIndex] ;
            if (type == XSParticleDecl.PARTICLE_ELEMENT) {
                matchingDecl = subGroupHandler.getMatchingElemDecl(curElem, (XSElementDecl)fElemMap[elemIndex]);
                if (matchingDecl != null) {
                    return matchingDecl;
                }
            }
            else if (type == XSParticleDecl.PARTICLE_WILDCARD) {
                if(((XSWildcardDecl)fElemMap[elemIndex]).allowNamespace(curElem.uri))
                    return fElemMap[elemIndex];
            }
        }

        return null;
    }

    // This method returns the start states of the content model.
    public int[] startContentModel() {
        int[] val = new int[2];
        val[0] = 0;
        fOneTransitionCounter = 0;      // reset transition counter
        return val;
    } // startContentModel():int[]

    // this method returns whether the last state was a valid final state
    public boolean endContentModel(int[] state) {
        return fFinalStateFlags[state[0]];