/* Woodstox XML processor
 *
 * Copyright (c) 2004- Tatu Saloranta, tatu.saloranta@iki.fi
 *
 * Licensed under the License specified in file LICENSE, included with
 * the source code.
 * You may not use this file except in compliance with the License.
 *
 * 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.ctc.wstx.dtd;

import java.util.*;

import javax.xml.stream.XMLStreamException;

import org.codehaus.stax2.validation.*;

import com.ctc.wstx.cfg.ErrorConsts;
import com.ctc.wstx.ent.EntityDecl;
import com.ctc.wstx.util.DataUtil;
import com.ctc.wstx.util.ElementId;
import com.ctc.wstx.util.ElementIdMap;
import com.ctc.wstx.util.PrefixedName;
import com.ctc.wstx.util.StringUtil;

Woodstox implementation of XMLValidator; the class that handles DTD-based validation. /**
 * Woodstox implementation of {@link XMLValidator}; the class that
 * handles DTD-based validation.
 */
public class DTDValidator
    extends DTDValidatorBase
{
    /*
    ///////////////////////////////////////
    // Configuration
    ///////////////////////////////////////
    */

    
Determines if identical problems (definition of the same element,
for example) should cause multiple error notifications or not:
if true, will get one error per instance, if false, only the first
one will get reported.
/**
     * Determines if identical problems (definition of the same element,
     * for example) should cause multiple error notifications or not:
     * if true, will get one error per instance, if false, only the first
     * one will get reported.
     */
    protected boolean mReportDuplicateErrors = false;

    /*
    ///////////////////////////////////////
    // Id/idref state
    ///////////////////////////////////////
    */

    
Information about declared and referenced element ids (unique
ids that attributes may defined, as defined by DTD)
/**
     * Information about declared and referenced element ids (unique
     * ids that attributes may defined, as defined by DTD)
     */
    protected ElementIdMap mIdMap = null;

    /*
    ///////////////////////////////////////////
    // Element def/spec/validator stack, state
    ///////////////////////////////////////////
    */

    
Stack of validators for open elements
/**
     * Stack of validators for open elements
     */
    protected StructValidator[] mValidators = null;

    
Bitset used for keeping track of required and defaulted attributes
for which values have been found.
/**
     * Bitset used for keeping track of required and defaulted attributes
     * for which values have been found.
     */
    protected BitSet mCurrSpecialAttrs = null;

    boolean mCurrHasAnyFixed = false;

    /*
    ///////////////////////////////////////
    // Temporary helper objects
    ///////////////////////////////////////
    */

    
Reusable lazily instantiated BitSet; needed to keep track of
missing 'special' attributes (required ones, ones with default
values)
/**
     * Reusable lazily instantiated BitSet; needed to keep track of
     * missing 'special' attributes (required ones, ones with default
     * values)
     */
    BitSet mTmpSpecialAttrs;

    /*
    ///////////////////////////////////////
    // Life-cycle
    ///////////////////////////////////////
    */

    public DTDValidator(DTDSubset schema, ValidationContext ctxt, boolean hasNsDefaults,
                        Map<PrefixedName,DTDElement> elemSpecs, Map<String,EntityDecl> genEntities)
    {
        super(schema, ctxt, hasNsDefaults, elemSpecs, genEntities);
        mValidators = new StructValidator[DEFAULT_STACK_SIZE];
    }

    @Override
    public final boolean reallyValidating() { return true; }

    /*
    ///////////////////////////////////////
    // XMLValidator implementation
    ///////////////////////////////////////
    */

    //public XMLValidationSchema getSchema();

    
Method called to update information about the newly encountered (start)
element. At this point namespace information has been resolved, but
no DTD validation has been done. Validator is to do these validations,
including checking for attribute value (and existence) compatibility.
/**
     * Method called to update information about the newly encountered (start)
     * element. At this point namespace information has been resolved, but
     * no DTD validation has been done. Validator is to do these validations,
     * including checking for attribute value (and existence) compatibility.
     */
    @Override
    public void validateElementStart(String localName, String uri, String prefix)
        throws XMLStreamException
    {
        /* Ok, need to find the element definition; if not found (or
         * only implicitly defined), need to throw the exception.
         */
        mTmpKey.reset(prefix, localName);

        DTDElement elem = mElemSpecs.get(mTmpKey);

        /* Let's add the entry in (even if it's a null); this is necessary
         * to keep things in-sync if allowing graceful handling of validity
         * errors
         */
        int elemCount = mElemCount++;
        if (elemCount >= mElems.length) {
            mElems = (DTDElement[]) DataUtil.growArrayBy50Pct(mElems);
            mValidators = (StructValidator[]) DataUtil.growArrayBy50Pct(mValidators);
        }
        mElems[elemCount] = mCurrElem = elem;
        if (elem == null || !elem.isDefined()) {
            reportValidationProblem(ErrorConsts.ERR_VLD_UNKNOWN_ELEM, mTmpKey.toString());
        }

        // Is this element legal under the parent element?
        StructValidator pv = (elemCount > 0) ? mValidators[elemCount-1] : null;

        if (pv != null && elem != null) {
            String msg = pv.tryToValidate(elem.getName());
            if (msg != null) {
                int ix = msg.indexOf("$END");
                String pname = mElems[elemCount-1].toString();
                if (ix >= 0) {
                    msg = msg.substring(0, ix) + "</"+pname+">"
                        +msg.substring(ix+4);
                }
                reportValidationProblem("Validation error, encountered element <"
                                        +elem.getName()+"> as a child of <"
                                        +pname+">: "+msg);
            }
        }

        mAttrCount = 0;
        mIdAttrIndex = -2; // -2 as a "don't know yet" marker

        // Ok, need to get the child validator, then:
        if (elem == null) {
            mValidators[elemCount] = null;
            mCurrAttrDefs = NO_ATTRS;
            mCurrHasAnyFixed = false;
            mCurrSpecialAttrs = null;
        } else {
            mValidators[elemCount] = elem.getValidator();
            mCurrAttrDefs = elem.getAttributes();
            if (mCurrAttrDefs == null) {
                mCurrAttrDefs = NO_ATTRS;
            }
            mCurrHasAnyFixed = elem.hasFixedAttrs();
            int specCount = elem.getSpecialCount();
            if (specCount == 0) {
                mCurrSpecialAttrs = null;
            } else {
                BitSet bs = mTmpSpecialAttrs;
                if (bs == null) {
                    mTmpSpecialAttrs = bs = new BitSet(specCount);
                } else {
                    bs.clear();
                }
                mCurrSpecialAttrs = bs;
            }
        }
    }

    @Override
    public String validateAttribute(String localName, String uri,
                                    String prefix, String value)
        throws XMLStreamException
    {
        DTDAttribute attr = mCurrAttrDefs.get(mTmpKey.reset(prefix, localName));
        if (attr == null) {
            // Only report error if not already recovering from an error:
            if (mCurrElem != null) {
                reportValidationProblem(ErrorConsts.ERR_VLD_UNKNOWN_ATTR,
                                        mCurrElem.toString(), mTmpKey.toString());
            }
            /* [WSTX-190] NPE if we continued (after reported didn't
             *   throw an exception); nothing more to do, let's leave
             */
            return value;
        }
        int index = mAttrCount++;
        if (index >= mAttrSpecs.length) {
            mAttrSpecs = (DTDAttribute[]) DataUtil.growArrayBy50Pct(mAttrSpecs);
        }
        mAttrSpecs[index] = attr;
        if (mCurrSpecialAttrs != null) { // Need to mark that we got it
            int specIndex = attr.getSpecialIndex();
            if (specIndex >= 0) {
                mCurrSpecialAttrs.set(specIndex);
            }
        }
        String result = attr.validate(this, value, mNormAttrs);
        if (mCurrHasAnyFixed && attr.isFixed()) {
            String act = (result == null) ? value : result;
            String exp = attr.getDefaultValue(mContext, this);
            if (!act.equals(exp)) {
                reportValidationProblem("Value of attribute \""+attr+"\" (element <"+mCurrElem+">) not \""+exp+"\" as expected, but \""+act+"\"");
            }
        }
        return result;
    }

    @Override
    public String validateAttribute(String localName, String uri,
                                    String prefix,
                                    char[] valueChars, int valueStart,
                                    int valueEnd)
        throws XMLStreamException
    {
        DTDAttribute attr = mCurrAttrDefs.get(mTmpKey.reset(prefix, localName));
        if (attr == null) {
            // Only report error if not already covering from an error:
            if (mCurrElem != null) {
                reportValidationProblem(ErrorConsts.ERR_VLD_UNKNOWN_ATTR,
                                        mCurrElem.toString(), mTmpKey.toString());
            }
            /* [WSTX-190] NPE if we continued (after reported didn't
             *   throw an exception); nothing more to do, let's leave
             */
            return new String(valueChars, valueStart, valueEnd);
        }
        int index = mAttrCount++;
        if (index >= mAttrSpecs.length) {
            mAttrSpecs = (DTDAttribute[]) DataUtil.growArrayBy50Pct(mAttrSpecs);
        }
        mAttrSpecs[index] = attr;
        if (mCurrSpecialAttrs != null) { // Need to mark that we got it
            int specIndex = attr.getSpecialIndex();
            if (specIndex >= 0) {
                mCurrSpecialAttrs.set(specIndex);
            }
        }
        String result = attr.validate(this, valueChars, valueStart, valueEnd, mNormAttrs);
        if (mCurrHasAnyFixed && attr.isFixed()) {
            String exp = attr.getDefaultValue(mContext, this);
            boolean match;
            if (result == null) {
                match = StringUtil.matches(exp, valueChars, valueStart, valueEnd - valueStart);
            } else {
                match = exp.equals(result);
            }
            if (!match) {
                String act = (result == null) ? 
                    new String(valueChars, valueStart, valueEnd) : result;
                reportValidationProblem("Value of #FIXED attribute \""+attr+"\" (element <"+mCurrElem+">) not \""+exp+"\" as expected, but \""+act+"\"");
            }
        }
        return result;
    }

    @Override
    public int validateElementAndAttributes()
        throws XMLStreamException
    {
        // Ok: are we fine with the attributes?
        DTDElement elem = mCurrElem;
        if (elem == null) { // had an error, most likely no such element defined...
            // need to just return, nothing to do here
            return XMLValidator.CONTENT_ALLOW_ANY_TEXT;
        }
        
        // Any special attributes missing?
        if (mCurrSpecialAttrs != null) {
            BitSet specBits = mCurrSpecialAttrs;
            int specCount = elem.getSpecialCount();
            int ix = specBits.nextClearBit(0);
            while (ix < specCount) { // something amiss!
                List<DTDAttribute> specAttrs = elem.getSpecialAttrs();
                DTDAttribute attr = specAttrs.get(ix);

                /* [WSTX-155]: Problems if reportValidationProblem returns
                 *   ok (which happens if a reporter handles it). So what
                 *   to do with missing required value? First thought is
                 *   to just leave it as is.
                 */
                if (attr.isRequired()) {
                    reportValidationProblem("Required attribute \"{0}\" missing from element <{1}>", attr, elem);
                } else {
                    doAddDefaultValue(attr);
                }
                ix = specBits.nextClearBit(ix+1);
            }
        }

        return elem.getAllowedContent();
    }

    
Returns:
Validation state that should be effective for the parent
  element state/**
     * @return Validation state that should be effective for the parent
     *   element state
     */
    @Override
    public int validateElementEnd(String localName, String uri, String prefix)
        throws XMLStreamException
    {
        // First, let's remove the top:
        int ix = mElemCount-1;
        /* [WSTX-200]: need to avoid problems when doing sub-tree
         *   validation...
         */
        if (ix < 0) {
            return XMLValidator.CONTENT_ALLOW_WS;
        }
        mElemCount = ix;

        DTDElement closingElem = mElems[ix];
        mElems[ix] = null;
        StructValidator v = mValidators[ix];
        mValidators[ix] = null;

        // Validation?
        if (v != null) {
            String msg = v.fullyValid();
            if (msg != null) {
                reportValidationProblem("Validation error, element </"
                                        +closingElem+">: "+msg);
            }
        }

        // Then let's get info from parent, if any
        if (ix < 1) { // root element closing..
            // doesn't really matter; epilog/prolog differently handled:
            return XMLValidator.CONTENT_ALLOW_WS;
        }
        return mElems[ix-1].getAllowedContent();
    }

    //public void validateText(String text, boolean lastTextSegment) ;
    //public void validateText(char[] cbuf, int textStart, int textEnd, boolean lastTextSegment) ;

    @Override
    public void validationCompleted(boolean eod) throws XMLStreamException
    {
        /* Need to now ensure that all IDREF/IDREFS references
         * point to defined ID attributes
         */
        checkIdRefs();
    }

    /*
    ///////////////////////////////////////
    // Package methods, accessors
    ///////////////////////////////////////
    */

    @Override
    protected ElementIdMap getIdMap() {
        if (mIdMap == null) {
            mIdMap = new ElementIdMap();
        }
        return mIdMap;
    }

    /*
    ///////////////////////////////////////
    // Internal methods
    ///////////////////////////////////////
    */

    protected void checkIdRefs()
        throws XMLStreamException
    {
        /* 02-Oct-2004, TSa: Now we can also check that all id references
         *    pointed to ids that actually are defined
         */
        if (mIdMap != null) {
            ElementId ref = mIdMap.getFirstUndefined();
            if (ref != null) { // problem!
                reportValidationProblem("Undefined id '"+ref.getId()
                                        +"': referenced from element <"
                                        +ref.getElemName()+">, attribute '"
                                        +ref.getAttrName()+"'",
                                        ref.getLocation());
            }
        }
    }

}