Copyright (c) 2004, 2009 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
    Jesper Steen Moeller - added namespace support
/*******************************************************************************
 * Copyright (c) 2004, 2009 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *     Jesper Steen Moeller - added namespace support
 *******************************************************************************/
package org.eclipse.core.runtime.content;

import java.io.*;
import java.util.*;
import javax.xml.parsers.ParserConfigurationException;
import org.eclipse.core.internal.content.ContentMessages;
import org.eclipse.core.internal.content.XMLRootHandler;
import org.eclipse.core.internal.runtime.RuntimeLog;
import org.eclipse.core.runtime.*;
import org.eclipse.osgi.util.NLS;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;

A content describer for detecting the name of the top-level element,
its namespace and the DTD system identifier in an XML file.

This executable extension supports "element" parameter, that
can be specified more than once. If the
":-" method is used, then the value is treated as
"element" (always just one)


The value of "element" is specified using such a format
{namespace}name/dtd. The namespace or dtd part
can be omitted and accepted are values like name/dtd,
{ns}name and name.


The describer will detect a document, if it matches at least one "element"
what means, that dtd, namespace (if specified) and name in "element"
match those in the document.


If the "element" name part is "*", e.g. {namespace}*,
it denotes a wildcard match. If the "element" namespace part is empty,
e.g. {}name, only these documents with the root element
that belong to the unnamed namespace xmlns=""
will be detected.

 This class should be used instead of XMLRootElementContentDescriber which doesn't detect namespaces and doesn't allow to specify more than one set of dtds, root element names and namespaces which should be detected. 

This class is not intended to be subclassed or instantiated by clients,
only to be referenced by the "describer" configuration element in
extensions to the org.eclipse.core.runtime.contentTypes
extension point.

Since:
org.eclipse.core.contenttype 3.3
@noinstantiate
This class is not intended to be instantiated by clients./**
 * A content describer for detecting the name of the top-level element,
 * its namespace and the DTD system identifier in an XML file.
 * <p>
 * This executable extension supports "element" parameter, that
 * can be specified more than once. If the
 * <code>":-"</code> method is used, then the value is treated as
 * "element" (always just one)
 * </p>
 * <p>
 * The value of "element" is specified using such a format
 * <code>{namespace}name/dtd</code>. The namespace or dtd part
 * can be omitted and accepted are values like <code>name/dtd</code>,
 * <code>{ns}name</code> and <code>name</code>.
 * </p>
 * <p>
 * The describer will detect a document, if it matches at least one "element"
 * what means, that dtd, namespace (if specified) and name in "element"
 * match those in the document.
 * </p>
 * <p>
 * If the "element" name part is "*", e.g. <code>{namespace}*</code>,
 * it denotes a wildcard match. If the "element" namespace part is empty,
 * e.g. <code>{}name</code>, only these documents with the root element
 * that belong to the unnamed namespace <code>xmlns=""</code>
 * will be detected.
 * </p>
 * <p>
 * This class should be used instead of {@link XMLRootElementContentDescriber}
 * which doesn't detect namespaces and doesn't allow to specify
 * more than one set of dtds, root element names and namespaces which
 * should be detected.
 * </p>
 * <p>
 * This class is not intended to be subclassed or instantiated by clients,
 * only to be referenced by the "describer" configuration element in
 * extensions to the <code>org.eclipse.core.runtime.contentTypes</code>
 * extension point.
 * </p>
 *
 * @since org.eclipse.core.contenttype 3.3
 * @noinstantiate This class is not intended to be instantiated by clients.
 */
public final class XMLRootElementContentDescriber2 extends XMLContentDescriber implements IExecutableExtension {

	static final String DTD = "org.eclipse.core.runtime.content.XMLRootElementContentDescriber2.dtd"; //$NON-NLS-1$
	static final String NAMESPACE = "org.eclipse.core.runtime.content.XMLRootElementContentDescriber2.namespace"; //$NON-NLS-1$
	static final String ELEMENT = "org.eclipse.core.runtime.content.XMLRootElementContentDescriber2.element"; //$NON-NLS-1$
	static final String RESULT = "org.eclipse.core.runtime.content.XMLRootElementContentDescriber2.result"; //$NON-NLS-1$

	private static final String ELEMENT_TO_FIND = "element"; //$NON-NLS-1$

	/* (Intentionally not included in javadoc)
	 * The top-level elements we are looking for. This value will be initialized
	 * by the <code>setInitializationData</code> method. If no value is
	 * provided, then this means that we don't care what the top-level element
	 * will be. The list is a collection of <code>QualifiedElement</code>.
	 */
	private QualifiedElement[] elementsToFind = null;

	/* (Intentionally not included in javadoc)
	 * Simple value holder for root element name, its namespace and dtd.
	 */
	private class QualifiedElement {
		private String namespace;
		private String element;
		private String dtd;

		public QualifiedElement(String qualifiedElement) {
			// Extract namespace part
			int openBrace = qualifiedElement.indexOf('{');
			int closeBrace = qualifiedElement.indexOf('}');
			if (openBrace == 0 && closeBrace >= 1) {
				namespace = qualifiedElement.substring(1, closeBrace);
				qualifiedElement = qualifiedElement.substring(closeBrace + 1);
			}
			// Extract dtd part
			int dtdSlash = qualifiedElement.indexOf('/');
			if (dtdSlash > 0) {
				dtd = qualifiedElement.substring(dtdSlash + 1);
				qualifiedElement = qualifiedElement.substring(0, dtdSlash);
			}
			// Check if the name is a wildcard
			element = ("*".equals(qualifiedElement) ? null : qualifiedElement); //$NON-NLS-1$
		}

		public boolean matches(String someNamespace, String someElement, String someDtd) {
			boolean nsMatch = this.namespace != null ? this.namespace.equals(someNamespace) : true;
			boolean elementEquals = this.element != null ? this.element.equals(someElement) : true;
			boolean dtdEquals = this.dtd != null ? this.dtd.equals(someDtd) : true;
			return nsMatch && elementEquals && dtdEquals;
		}
	}

	/* (Intentionally not included in javadoc)
	 * Determines the validation status for the given contents.
	 *
	 * @param contents the contents to be evaluated
	 * @return one of the following:<ul>
	 * <li><code>VALID</code></li>,
	 * <li><code>INVALID</code></li>,
	 * <li><code>INDETERMINATE</code></li>
	 * </ul>
	 * @throws IOException
	 */
	private int checkCriteria(InputSource contents, Map<String, Object> properties) throws IOException {
		if (!isProcessed(properties))
			fillContentProperties(contents, properties);
		return checkCriteria(properties);
	}

	private int checkCriteria(Map<String, Object> properties) throws IOException {
		Boolean result = (Boolean) properties.get(RESULT);
		if (!result.booleanValue())
			return INDETERMINATE;
		// Check to see if we matched our criteria.
		if (elementsToFind != null) {
			boolean foundOne = false;
			for (int i = 0; i < elementsToFind.length && !foundOne; ++i) {
				String dtd = (String) properties.get(DTD);
				String namespace = (String) properties.get(NAMESPACE);
				String element = (String) properties.get(ELEMENT);
				foundOne |= elementsToFind[i].matches(namespace, element, dtd);
			}
			if (!foundOne)
				return INDETERMINATE;
		}
		// We must be okay then.
		return VALID;
	}

	@Override
	public int describe(InputStream contents, IContentDescription description) throws IOException {
		return describe(contents, description, new HashMap<>());
	}

	
@noreference
This method is not intended to be referenced by clients./**
	 * @noreference This method is not intended to be referenced by clients.
	 */
	public int describe(InputStream contents, IContentDescription description, Map<String, Object> properties) throws IOException {
		// call the basic XML describer to do basic recognition
		if (super.describe2(contents, description, properties) == INVALID)
			return INVALID;
		// super.describe will have consumed some chars, need to rewind
		contents.reset();
		// Check to see if we matched our criteria.
		return checkCriteria(new InputSource(contents), properties);
	}

	@Override
	public int describe(Reader contents, IContentDescription description) throws IOException {
		return describe(contents, description, new HashMap<>());
	}

	
@noreference
This method is not intended to be referenced by clients./**
	 * @noreference This method is not intended to be referenced by clients.
	 */
	public int describe(Reader contents, IContentDescription description, Map<String, Object> properties) throws IOException {
		// call the basic XML describer to do basic recognition
		if (super.describe2(contents, description, properties) == INVALID)
			return INVALID;
		// super.describe will have consumed some chars, need to rewind
		contents.reset();
		// Check to see if we matched our criteria.
		return checkCriteria(new InputSource(contents), properties);
	}

	static boolean isProcessed(Map<String, Object> properties) {
		Boolean result = (Boolean) properties.get(RESULT);
		// It can be set to false which means that content can't be parsed
		if (result != null)
			return true;
		return false;
	}

	static void fillContentProperties(InputSource input, Map<String, Object> properties) throws IOException {
		XMLRootHandler xmlHandler = new XMLRootHandler(true);
		try {
			if (!xmlHandler.parseContents(input)) {
				properties.put(RESULT, Boolean.FALSE);
				return;
			}
		} catch (SAXException e) {
			// we may be handed any kind of contents... it is normal we fail to parse
			properties.put(RESULT, Boolean.FALSE);
			return;
		} catch (ParserConfigurationException e) {
			// some bad thing happened - force this describer to be disabled
			String message = ContentMessages.content_parserConfiguration;
			RuntimeLog.log(new Status(IStatus.ERROR, ContentMessages.OWNER_NAME, 0, message, e));
			throw new RuntimeException(message);
		}
		String element = xmlHandler.getRootName();
		if (element != null)
			properties.put(ELEMENT, element);
		String dtd = xmlHandler.getDTD();
		if (dtd != null)
			properties.put(DTD, dtd);
		String namespace = xmlHandler.getRootNamespace();
		if (namespace != null)
			properties.put(NAMESPACE, namespace);
		properties.put(RESULT, Boolean.TRUE);
	}

	@Override
	public void setInitializationData(final IConfigurationElement config, final String propertyName, final Object data) throws CoreException {
		if (data instanceof String)
			elementsToFind = new QualifiedElement[] {new QualifiedElement((String) data)};
		else if (data instanceof Hashtable) {
			List<QualifiedElement> elements = null;

			// the describer parameters have to be read again, because "element" parameter can be specified multiple times
			// and the given hashtable carries only one of them
			IConfigurationElement describerElement = config.getChildren("describer")[0]; //$NON-NLS-1$
			IConfigurationElement[] params = describerElement.getChildren("parameter"); //$NON-NLS-1$
			String pname = null;
			for (IConfigurationElement param : params) {
				pname = param.getAttribute("name"); //$NON-NLS-1$
				if (ELEMENT_TO_FIND.equals(pname)) {
					if (elements == null)
						elements = new LinkedList<>();
					elements.add(new QualifiedElement(param.getAttribute("value"))); //$NON-NLS-1$
				}
			}

			List<QualifiedElement> qualifiedElements = new ArrayList<>();

			// create list of qualified elements
			if (elements != null) {
				qualifiedElements.addAll(elements);
			}
			elementsToFind = qualifiedElements.toArray(new QualifiedElement[qualifiedElements.size()]);
		}

		if (elementsToFind.length == 0) {
			String message = NLS.bind(ContentMessages.content_badInitializationData, XMLRootElementContentDescriber2.class.getName());
			throw new CoreException(new Status(IStatus.ERROR, ContentMessages.OWNER_NAME, 0, message, null));
		}
	}
}