/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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
    *
    *      https://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 org.apache.commons.xml.secure;
  
  import java.util.Objects;
  import java.util.function.Supplier;
  
  import javax.xml.transform.Result;
  import javax.xml.transform.Source;
  import javax.xml.transform.Transformer;
  import javax.xml.transform.URIResolver;
  import javax.xml.transform.sax.TransformerHandler;
  
  import org.xml.sax.Attributes;
  import org.xml.sax.Locator;
  import org.xml.sax.SAXException;
  
  /**
   * {@link TransformerHandler} wrapper that keeps an ignore-all {@link URIResolver} floor on the live transformer the handler transforms with.
   *
   * <p>The handler's input is SAX events the caller drives, so it has no inner source-parsing path of its own. What needs the floor is its transformer: the
   * handler runs the transformation on the object {@link TransformerHandler#getTransformer()} exposes, and not every implementation seeds that transformer with
   * the factory's resolver (the stock JDK's {@code newTransformerHandler(Templates)} does not). Wrapping that transformer in a {@link SecureTransformer} at
   * construction installs the floor on the live instance, so runtime {@code document()} during the handler's transform is covered, and so is a caller who pulls
   * the transformer out through {@code getTransformer()}.</p>
   */
  final class SecureTransformerHandler implements TransformerHandler {
  
      private final TransformerHandler delegate;
  
      /**
       * Wraps the handler's LIVE transformer; constructing it installs the resolver floor that the handler's own transform then runs under.
       */
      private final SecureTransformer transformer;
  
      /**
       * Constructs a new instance.
       *
       * @param delegate the delegate to wrap; must not be {@code null}.
       * @param uriResolver the compile-time URIResolver snapshot to restore onto the live transformer; may be {@code null}.
       * @param emptySource the empty-{@link Source} supplier for the produced Transformer's floor; {@code null} means the default empty DOM.
       * @param overrideDefaultParser whether the live transformer's source rewrites should use the pluggable parser lookup instead of the platform's built-in parser.
       * @throws NullPointerException if {@code delegate} is {@code null}.
       */
      SecureTransformerHandler(final TransformerHandler delegate, final URIResolver uriResolver, final Supplier<Source> emptySource,
              final boolean overrideDefaultParser) {
          this.delegate = Objects.requireNonNull(delegate, "delegate");
          this.transformer = new SecureTransformer(delegate.getTransformer(), uriResolver, emptySource, overrideDefaultParser);
      }
  
      @Override
      public void characters(final char[] ch, final int start, final int length) throws SAXException {
          delegate.characters(ch, start, length);
      }
  
      @Override
      public void comment(final char[] ch, final int start, final int length) throws SAXException {
          delegate.comment(ch, start, length);
      }
  
  
      @Override
      public void endCDATA() throws SAXException {
          delegate.endCDATA();
      }
  
      @Override
      public void endDocument() throws SAXException {
          delegate.endDocument();
      }
  
      @Override
      public void endDTD() throws SAXException {
          delegate.endDTD();
      }
  
      @Override
      public void endElement(final String uri, final String localName, final String qName) throws SAXException {
          delegate.endElement(uri, localName, qName);
      }
  
      @Override
      public void endEntity(final String name) throws SAXException {
          delegate.endEntity(name);
     }
 
     @Override
     public void endPrefixMapping(final String prefix) throws SAXException {
         delegate.endPrefixMapping(prefix);
     }
 
     @Override
     public String getSystemId() {
         return delegate.getSystemId();
     }
 
     @Override
     public Transformer getTransformer() {
         return transformer;
     }
 
     @Override
     public void ignorableWhitespace(final char[] ch, final int start, final int length) throws SAXException {
         delegate.ignorableWhitespace(ch, start, length);
     }
 
     @Override
     public void notationDecl(final String name, final String publicId, final String systemId) throws SAXException {
         delegate.notationDecl(name, publicId, systemId);
     }
 
     @Override
     public void processingInstruction(final String target, final String data) throws SAXException {
         delegate.processingInstruction(target, data);
     }
 
     @Override
     public void setDocumentLocator(final Locator locator) {
         delegate.setDocumentLocator(locator);
     }
 
     @Override
     public void setResult(final Result result) {
         delegate.setResult(result);
     }
 
     @Override
     public void setSystemId(final String systemID) {
         delegate.setSystemId(systemID);
     }
 
     @Override
     public void skippedEntity(final String name) throws SAXException {
         delegate.skippedEntity(name);
     }
 
     @Override
     public void startCDATA() throws SAXException {
         delegate.startCDATA();
     }
 
     @Override
     public void startDocument() throws SAXException {
         delegate.startDocument();
     }
 
     @Override
     public void startDTD(final String name, final String publicId, final String systemId) throws SAXException {
         delegate.startDTD(name, publicId, systemId);
     }
 
     @Override
     public void startElement(final String uri, final String localName, final String qName, final Attributes atts) throws SAXException {
         delegate.startElement(uri, localName, qName, atts);
     }
 
     @Override
     public void startEntity(final String name) throws SAXException {
         delegate.startEntity(name);
     }
 
     @Override
     public void startPrefixMapping(final String prefix, final String uri) throws SAXException {
         delegate.startPrefixMapping(prefix, uri);
     }
 
     @Override
     public void unparsedEntityDecl(final String name, final String publicId, final String systemId, final String notationName) throws SAXException {
         delegate.unparsedEntityDecl(name, publicId, systemId, notationName);
     }
 }