/*
    * Copyright 2009 Google Inc.
    * 
    * 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.google.gwt.uibinder.rebind;
  
  import com.google.gwt.core.ext.TreeLogger;
  import com.google.gwt.dev.resource.ResourceOracle;
  
  import org.w3c.dom.Document;
  import org.xml.sax.InputSource;
  import org.xml.sax.SAXException;
  import org.xml.sax.SAXParseException;
  
  import java.io.IOException;
  import java.io.StringReader;
  
  import javax.xml.parsers.ParserConfigurationException;
  import javax.xml.parsers.SAXParser;
  import javax.xml.parsers.SAXParserFactory;
  
  /**
   * Simplifies instantiation of the w3c XML parser, in just the style that
   * UiBinder likes it. Used by both prod and test.
   */
  public class W3cDomHelper {
    private static final String LOAD_EXTERNAL_DTD =
        "http://apache.org/xml/features/nonvalidating/load-external-dtd";
  
    private final SAXParserFactory factory;
    private final TreeLogger logger;
    private final ResourceOracle resourceOracle;
  
    public W3cDomHelper(TreeLogger logger, ResourceOracle resourceOracle) {
      this.logger = logger;
      this.resourceOracle = resourceOracle;
      factory = SAXParserFactory.newInstance();
      try {
        factory.setFeature(LOAD_EXTERNAL_DTD, true);
      } catch (ParserConfigurationException e) {
        throw new RuntimeException(e);
      } catch (SAXException e) {
        // ignore since parser doesn't know about this feature
      }
      factory.setNamespaceAware(true);
    }
  
    /**
     * Creates an XML document model with the given contents.
     */
    public Document documentFor(String string, String resourcePath)
        throws SAXParseException {
      try {
        // laaglu
          factory.setFeature("http://xml.org/sax/features/xmlns-uris", true);
          factory.setFeature("http://xml.org/sax/features/namespace-prefixes", true);
        // laaglu
        if (resourcePath != null) {
          int pos = resourcePath.lastIndexOf('/');
          resourcePath = (pos < 0) ? "" : resourcePath.substring(0, pos + 1);
        }
        W3cDocumentBuilder handler = new W3cDocumentBuilder(logger, resourcePath,
            resourceOracle);
        SAXParser parser = factory.newSAXParser();
        InputSource input = new InputSource(new StringReader(string));
        input.setSystemId(resourcePath);
        parser.parse(input, handler);
        return handler.getDocument();
      } catch (SAXParseException e) {
        // Let SAXParseExceptions through.
        throw e;
      } catch (SAXException e) {
        throw new RuntimeException(e);
      } catch (IOException e) {
        throw new RuntimeException(e);
      } catch (ParserConfigurationException e) {
        throw new RuntimeException(e);
      }
    }
  }