Copyright (c) 2000, 2018 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
/*******************************************************************************
 * Copyright (c) 2000, 2018 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
 *******************************************************************************/

package org.eclipse.core.internal.registry;

import java.io.IOException;
import java.util.*;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import org.eclipse.core.runtime.*;
import org.eclipse.osgi.util.NLS;
import org.xml.sax.*;
import org.xml.sax.helpers.DefaultHandler;

public class ExtensionsParser extends DefaultHandler {
	// Introduced for backward compatibility
	private final static String NO_EXTENSION_MUNGING = "eclipse.noExtensionMunging"; //$NON-NLS-1$ //System property
	private static final String VERSION_3_0 = "3.0"; //$NON-NLS-1$
	private static final String VERSION_3_2 = "3.2"; //$NON-NLS-1$
	private static Map<String, String> extensionPointMap;

	static {
		initializeExtensionPointMap();
	}

	
Initialize the list of renamed extension point ids
/**
	 * Initialize the list of renamed extension point ids
	 */
	private static void initializeExtensionPointMap() {
		Map<String, String> map = new HashMap<>(13);
		map.put("org.eclipse.ui.markerImageProvider", "org.eclipse.ui.ide.markerImageProvider"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.markerHelp", "org.eclipse.ui.ide.markerHelp"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.markerImageProviders", "org.eclipse.ui.ide.markerImageProviders"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.markerResolution", "org.eclipse.ui.ide.markerResolution"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.projectNatureImages", "org.eclipse.ui.ide.projectNatureImages"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.resourceFilters", "org.eclipse.ui.ide.resourceFilters"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.markerUpdaters", "org.eclipse.ui.editors.markerUpdaters"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.documentProviders", "org.eclipse.ui.editors.documentProviders"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.ui.workbench.texteditor.markerAnnotationSpecification", "org.eclipse.ui.editors.markerAnnotationSpecification"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.help.browser", "org.eclipse.help.base.browser"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.help.luceneAnalyzer", "org.eclipse.help.base.luceneAnalyzer"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.help.webapp", "org.eclipse.help.base.webapp"); //$NON-NLS-1$ //$NON-NLS-2$
		map.put("org.eclipse.help.support", "org.eclipse.ui.helpSupport"); //$NON-NLS-1$ //$NON-NLS-2$
		extensionPointMap = map;
	}

	private static long cumulativeTime = 0;

	// is in compatibility mode
	private boolean compatibilityMode;

	// File name for this extension manifest
	// This to help with error reporting
	private String locationName = null;

	// Current State Information
	private final Stack<Integer> stateStack = new Stack<>();

	// Current object stack (used to hold the current object we are
	// populating in this plugin descriptor
	private final Stack<KeyedElement> objectStack = new Stack<>();

	private String schemaVersion = null;

	// A status for holding results.
	private final MultiStatus status;

	// Owning extension registry
	private final ExtensionRegistry registry;

	// Resource bundle used to translate the content of the plugin.xml
	protected ResourceBundle resources;

	// Keep track of the object encountered.
	private RegistryObjectManager objectManager;

	private Contribution contribution;

	//This keeps tracks of the value of the configuration element in case the value comes in several pieces (see characters()). See as well bug 75592.
	private String configurationElementValue;

	
Status code constant (value 1) indicating a problem in a bundle extensions
manifest (extensions.xml) file.
/**
	 * Status code constant (value 1) indicating a problem in a bundle extensions
	 * manifest (<code>extensions.xml</code>) file.
	 */
	public static final int PARSE_PROBLEM = 1;

	public static final String PLUGIN = "plugin"; //$NON-NLS-1$
	public static final String PLUGIN_ID = "id"; //$NON-NLS-1$
	public static final String PLUGIN_NAME = "name"; //$NON-NLS-1$
	public static final String FRAGMENT = "fragment"; //$NON-NLS-1$
	public static final String BUNDLE_UID = "id"; //$NON-NLS-1$

	public static final String EXTENSION_POINT = "extension-point"; //$NON-NLS-1$
	public static final String EXTENSION_POINT_NAME = "name"; //$NON-NLS-1$
	public static final String EXTENSION_POINT_ID = "id"; //$NON-NLS-1$
	public static final String EXTENSION_POINT_SCHEMA = "schema"; //$NON-NLS-1$

	public static final String EXTENSION = "extension"; //$NON-NLS-1$
	public static final String EXTENSION_NAME = "name"; //$NON-NLS-1$
	public static final String EXTENSION_ID = "id"; //$NON-NLS-1$
	public static final String EXTENSION_TARGET = "point"; //$NON-NLS-1$

	public static final String ELEMENT = "element"; //$NON-NLS-1$
	public static final String ELEMENT_NAME = "name"; //$NON-NLS-1$
	public static final String ELEMENT_VALUE = "value"; //$NON-NLS-1$

	public static final String PROPERTY = "property"; //$NON-NLS-1$
	public static final String PROPERTY_NAME = "name"; //$NON-NLS-1$
	public static final String PROPERTY_VALUE = "value"; //$NON-NLS-1$

	// Valid States
	private static final int IGNORED_ELEMENT_STATE = 0;
	private static final int INITIAL_STATE = 1;
	private static final int BUNDLE_STATE = 2;
	private static final int BUNDLE_EXTENSION_POINT_STATE = 5;
	private static final int BUNDLE_EXTENSION_STATE = 6;
	private static final int CONFIGURATION_ELEMENT_STATE = 10;

	// Keep a group of vectors as a temporary scratch space.  These
	// vectors will be used to populate arrays in the bundle model
	// once processing of the XML file is complete.
	private static final int EXTENSION_POINT_INDEX = 0;
	private static final int EXTENSION_INDEX = 1;
	private static final int LAST_INDEX = 1;

	@SuppressWarnings("unchecked")
	private final ArrayList<RegistryObject> scratchVectors[] = new ArrayList[LAST_INDEX + 1];

	private Locator locator = null;

	// Cache the behavior toggle (true: attempt to extract namespace from qualified IDs)
	private boolean extractNamespaces = false;

	private ArrayList<String> processedExtensionIds = null;

	// Keep track of elements added into the registry manager in case we encounter a error
	// and need to rollback
	private final ArrayList<RegistryObject> addedRegistryObjects = new ArrayList<>(5);

	public ExtensionsParser(MultiStatus status, ExtensionRegistry registry) {
		super();
		this.status = status;
		this.registry = registry;
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#setDocumentLocator(org.xml.sax.Locator)
	 */
	@Override
	public void setDocumentLocator(Locator locator) {
		this.locator = locator;
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#characters(char[], int, int)
	 */
	@Override
	public void characters(char[] ch, int start, int length) {
		int state = stateStack.peek().intValue();
		if (state != CONFIGURATION_ELEMENT_STATE)
			return;
		if (state == CONFIGURATION_ELEMENT_STATE) {
			// Accept character data within an element, is when it is
			// part of a configuration element (i.e. an element within an EXTENSION element
			ConfigurationElement currentConfigElement = (ConfigurationElement) objectStack.peek();
			String value = new String(ch, start, length);
			if (configurationElementValue == null) {
				if (value.trim().length() != 0) {
					configurationElementValue = value;
				}
			} else {
				configurationElementValue = configurationElementValue + value;
			}
			if (configurationElementValue != null)
				currentConfigElement.setValue(configurationElementValue);
		}
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#endDocument()
	 */
	@Override
	public void endDocument() {
		// do nothing
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
	 */
	@Override
	public void endElement(String uri, String elementName, String qName) {
		switch (stateStack.peek().intValue()) {
			case IGNORED_ELEMENT_STATE :
				stateStack.pop();
				break;
			case INITIAL_STATE :
				// shouldn't get here
				internalError(NLS.bind(RegistryMessages.parse_internalStack, elementName));
				break;
			case BUNDLE_STATE :
				stateStack.pop();

				ArrayList<?> extensionPoints = scratchVectors[EXTENSION_POINT_INDEX];
				ArrayList<?> extensions = scratchVectors[EXTENSION_INDEX];
				int[] namespaceChildren = new int[2 + extensionPoints.size() + extensions.size()];
				int position = 2;
				// Put the extension points into this namespace
				if (extensionPoints.size() > 0) {
					namespaceChildren[Contribution.EXTENSION_POINT] = extensionPoints.size();
					for (Iterator<?> iter = extensionPoints.iterator(); iter.hasNext();) {
						namespaceChildren[position++] = ((RegistryObject) iter.next()).getObjectId();
					}
					extensionPoints.clear();
				}

				// Put the extensions into this namespace too
				if (extensions.size() > 0) {
					Extension[] renamedExtensions = fixRenamedExtensionPoints(extensions.toArray(new Extension[extensions.size()]));
					namespaceChildren[Contribution.EXTENSION] = renamedExtensions.length;
					for (Extension renamedExtension : renamedExtensions) {
						namespaceChildren[position++] = renamedExtension.getObjectId();
					}
					extensions.clear();
				}
				contribution.setRawChildren(namespaceChildren);
				break;
			case BUNDLE_EXTENSION_POINT_STATE :
				if (elementName.equals(EXTENSION_POINT)) {
					stateStack.pop();
				}
				break;
			case BUNDLE_EXTENSION_STATE :
				if (elementName.equals(EXTENSION)) {
					stateStack.pop();
					// Finish up extension object
					Extension currentExtension = (Extension) objectStack.pop();
					if (currentExtension.getNamespaceIdentifier() == null)
						currentExtension.setNamespaceIdentifier(contribution.getDefaultNamespace());
					currentExtension.setContributorId(contribution.getContributorId());
					scratchVectors[EXTENSION_INDEX].add(currentExtension);
				}
				break;
			case CONFIGURATION_ELEMENT_STATE :
				// We don't care what the element name was
				stateStack.pop();
				// Now finish up the configuration element object
				configurationElementValue = null;
				ConfigurationElement currentConfigElement = (ConfigurationElement) objectStack.pop();

				String value = currentConfigElement.getValueAsIs();
				if (value != null) {
					currentConfigElement.setValue(translate(value).trim());
				}

				RegistryObject parent = (RegistryObject) objectStack.peek();
				// Want to add this configuration element to the subelements of an extension
				int[] oldValues = parent.getRawChildren();
				int size = oldValues.length;
				int[] newValues = new int[size + 1];
				for (int i = 0; i < size; i++) {
					newValues[i] = oldValues[i];
				}
				newValues[size] = currentConfigElement.getObjectId();
				parent.setRawChildren(newValues);
				currentConfigElement.setParentId(parent.getObjectId());
				currentConfigElement.setParentType(parent instanceof ConfigurationElement ? RegistryObjectManager.CONFIGURATION_ELEMENT : RegistryObjectManager.EXTENSION);
				break;
		}
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#error(org.xml.sax.SAXParseException)
	 */
	@Override
	public void error(SAXParseException ex) {
		logStatus(ex);
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#fatalError(org.xml.sax.SAXParseException)
	 */
	@Override
	public void fatalError(SAXParseException ex) throws SAXException {
		cleanup();
		logStatus(ex);
		throw ex;
	}

	
Remove all elements that we have added so far into registry manager
/**
	 * Remove all elements that we have added so far into registry manager
	 */
	private void cleanup() {
		for (RegistryObject object : addedRegistryObjects) {
			if (object instanceof ExtensionPoint) {
				String id = ((ExtensionPoint) object).getUniqueIdentifier();
				objectManager.removeExtensionPoint(id);
			} else
				objectManager.remove(object.getObjectId(), true);
		}
	}

	private void handleExtensionPointState(String elementName) {
		// We ignore all elements under extension points (if there are any)
		stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
		unknownElement(EXTENSION_POINT, elementName);
	}

	private void handleExtensionState(String elementName, Attributes attributes) {
		// You need to change the state here even though we will be executing the same
		// code for ExtensionState and ConfigurationElementState.  We ignore the name
		// of the element for ConfigurationElements.  When we are wrapping up, we will
		// want to add each configuration element object to the subElements vector of
		// its parent configuration element object.  However, the first configuration
		// element object we created (the last one we pop off the stack) will need to
		// be added to a vector in the extension object called _configuration.
		stateStack.push(Integer.valueOf(CONFIGURATION_ELEMENT_STATE));

		configurationElementValue = null;

		// create a new Configuration Element and push it onto the object stack
		ConfigurationElement currentConfigurationElement = registry.getElementFactory().createConfigurationElement(contribution.shouldPersist());
		currentConfigurationElement.setContributorId(contribution.getContributorId());
		objectStack.push(currentConfigurationElement);
		currentConfigurationElement.setName(elementName);

		// Processing the attributes of a configuration element involves creating
		// a new configuration property for each attribute and populating the configuration
		// property with the name/value pair of the attribute.  Note there will be one
		// configuration property for each attribute
		parseConfigurationElementAttributes(attributes);
		objectManager.add(currentConfigurationElement, true);
		addedRegistryObjects.add(currentConfigurationElement);
	}

	private void handleInitialState(String elementName, Attributes attributes) {
		// new manifests should have the plugin (or fragment) element empty
		// in compatibility mode, any extraneous elements will be silently ignored
		compatibilityMode = attributes.getLength() > 0;
		stateStack.push(Integer.valueOf(BUNDLE_STATE));
		objectStack.push(contribution);
	}

	private void handleBundleState(String elementName, Attributes attributes) {
		if (elementName.equals(EXTENSION_POINT)) {
			stateStack.push(Integer.valueOf(BUNDLE_EXTENSION_POINT_STATE));
			parseExtensionPointAttributes(attributes);
			return;
		}
		if (elementName.equals(EXTENSION)) {
			stateStack.push(Integer.valueOf(BUNDLE_EXTENSION_STATE));
			parseExtensionAttributes(attributes);
			return;
		}

		// If we get to this point, the element name is one we don't currently accept.
		// Set the state to indicate that this element will be ignored
		stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
		if (!compatibilityMode)
			unknownElement(PLUGIN, elementName);
	}

	private void logStatus(SAXParseException ex) {
		String name = ex.getSystemId();
		if (name == null)
			name = locationName;
		if (name == null)
			name = ""; //$NON-NLS-1$
		else
			name = name.substring(1 + name.lastIndexOf("/")); //$NON-NLS-1$

		String msg;
		if (name.equals("")) //$NON-NLS-1$
			msg = NLS.bind(RegistryMessages.parse_error, ex.getMessage());
		else
			msg = NLS.bind(RegistryMessages.parse_errorNameLineColumn, (new Object[] {name, Integer.toString(ex.getLineNumber()), Integer.toString(ex.getColumnNumber()), ex.getMessage()}));
		error(new Status(IStatus.WARNING, RegistryMessages.OWNER_NAME, PARSE_PROBLEM, msg, ex));
	}

	public Contribution parseManifest(SAXParserFactory factory, InputSource in, String manifestName, RegistryObjectManager registryObjects, Contribution currentNamespace, ResourceBundle bundle) throws ParserConfigurationException, SAXException, IOException {
		long start = 0;
		this.resources = bundle;
		this.objectManager = registryObjects;
		//initialize the parser with this object
		this.contribution = currentNamespace;
		if (registry.debug())
			start = System.currentTimeMillis();

		if (factory == null)
			throw new SAXException(RegistryMessages.parse_xmlParserNotAvailable);

		try {
			locationName = in.getSystemId();
			if (locationName == null)
				locationName = manifestName;
			factory.setNamespaceAware(true);
			try {
				factory.setFeature("http://xml.org/sax/features/string-interning", true); //$NON-NLS-1$
			} catch (SAXException se) {
				// ignore; we can still operate without string-interning
			}
			factory.setValidating(false);
			factory.newSAXParser().parse(in, this);
			return (Contribution) objectStack.pop();
		} finally {
			if (registry.debug()) {
				cumulativeTime = cumulativeTime + (System.currentTimeMillis() - start);
				System.out.println("Cumulative parse time so far : " + cumulativeTime); //$NON-NLS-1$
			}
		}
	}

	private void parseConfigurationElementAttributes(Attributes attributes) {
		ConfigurationElement parentConfigurationElement = (ConfigurationElement) objectStack.peek();

		// process attributes
		int len = (attributes != null) ? attributes.getLength() : 0;
		if (len == 0) {
			parentConfigurationElement.setProperties(RegistryObjectManager.EMPTY_STRING_ARRAY);
			return;
		}
		String[] properties = new String[len * 2];
		for (int i = 0; i < len; i++) {
			properties[i * 2] = attributes.getLocalName(i);
			properties[i * 2 + 1] = translate(attributes.getValue(i));
		}
		parentConfigurationElement.setProperties(properties);
		properties = null;
	}

	private void parseExtensionAttributes(Attributes attributes) {
		Extension currentExtension = registry.getElementFactory().createExtension(contribution.shouldPersist());
		objectStack.push(currentExtension);

		String simpleId = null;
		String namespaceName = null;
		// Process Attributes
		int len = (attributes != null) ? attributes.getLength() : 0;
		for (int i = 0; i < len; i++) {
			String attrName = attributes.getLocalName(i);
			String attrValue = attributes.getValue(i).trim();

			if (attrName.equals(EXTENSION_NAME))
				currentExtension.setLabel(translate(attrValue));
			else if (attrName.equals(EXTENSION_ID)) {
				int simpleIdStart = attrValue.lastIndexOf('.');
				if ((simpleIdStart != -1) && extractNamespaces) {
					simpleId = attrValue.substring(simpleIdStart + 1);
					namespaceName = attrValue.substring(0, simpleIdStart);
				} else {
					simpleId = attrValue;
					namespaceName = contribution.getDefaultNamespace();
				}
				currentExtension.setSimpleIdentifier(simpleId);
				currentExtension.setNamespaceIdentifier(namespaceName);
			} else if (attrName.equals(EXTENSION_TARGET)) {
				// check if point is specified as a simple or qualified name
				String targetName;
				if (attrValue.lastIndexOf('.') == -1) {
					String baseId = contribution.getDefaultNamespace();
					targetName = baseId + '.' + attrValue;
				} else
					targetName = attrValue;
				currentExtension.setExtensionPointIdentifier(targetName);
			} else
				unknownAttribute(attrName, EXTENSION);
		}
		if (currentExtension.getExtensionPointIdentifier() == null) {
			missingAttribute(EXTENSION_TARGET, EXTENSION);
			stateStack.pop();
			stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
			objectStack.pop();
			return;
		}
		// if we have an Id specified, check for duplicates. Only issue warning (not error) if duplicate found
		// as it might still work fine - depending on the access pattern.
		if (simpleId != null && registry.debug()) {
			String uniqueId = namespaceName + '.' + simpleId;
			IExtension existingExtension = registry.getExtension(uniqueId);
			if (existingExtension != null) {
				String currentSupplier = contribution.getDefaultNamespace();
				String existingSupplier = existingExtension.getContributor().getName();
				String msg = NLS.bind(RegistryMessages.parse_duplicateExtension, new String[] {currentSupplier, existingSupplier, uniqueId});
				registry.log(new Status(IStatus.WARNING, RegistryMessages.OWNER_NAME, 0, msg, null));
			} else if (processedExtensionIds != null) { // check elements in this contribution
				for (Iterator<String> i = processedExtensionIds.iterator(); i.hasNext();) {
					if (uniqueId.equals(i.next())) {
						String currentSupplier = contribution.getDefaultNamespace();
						String existingSupplier = currentSupplier;
						String msg = NLS.bind(RegistryMessages.parse_duplicateExtension, new String[] {currentSupplier, existingSupplier, uniqueId});
						registry.log(new Status(IStatus.WARNING, RegistryMessages.OWNER_NAME, 0, msg, null));
						break;
					}
				}
			}
			if (processedExtensionIds == null)
				processedExtensionIds = new ArrayList<>(10);
			processedExtensionIds.add(uniqueId);
		}

		objectManager.add(currentExtension, true);
		addedRegistryObjects.add(currentExtension);
	}

	//todo: Are all three methods needed??
	private void missingAttribute(String attribute, String element) {
		if (locator == null)
			internalError(NLS.bind(RegistryMessages.parse_missingAttribute, attribute, element));
		else
			internalError(NLS.bind(RegistryMessages.parse_missingAttributeLine, (new String[] {attribute, element, Integer.toString(locator.getLineNumber())})));
	}

	private void unknownAttribute(String attribute, String element) {
		if (locator == null)
			internalError(NLS.bind(RegistryMessages.parse_unknownAttribute, attribute, element));
		else
			internalError(NLS.bind(RegistryMessages.parse_unknownAttributeLine, (new String[] {attribute, element, Integer.toString(locator.getLineNumber())})));
	}

	private void unknownElement(String parent, String element) {
		if (locator == null)
			internalError(NLS.bind(RegistryMessages.parse_unknownElement, element, parent));
		else
			internalError(NLS.bind(RegistryMessages.parse_unknownElementLine, (new String[] {element, parent, Integer.toString(locator.getLineNumber())})));
	}

	private void parseExtensionPointAttributes(Attributes attributes) {
		ExtensionPoint currentExtPoint = registry.getElementFactory().createExtensionPoint(contribution.shouldPersist());

		// Process Attributes
		int len = (attributes != null) ? attributes.getLength() : 0;
		for (int i = 0; i < len; i++) {
			String attrName = attributes.getLocalName(i);
			String attrValue = attributes.getValue(i).trim();

			if (attrName.equals(EXTENSION_POINT_NAME))
				currentExtPoint.setLabel(translate(attrValue));
			else if (attrName.equals(EXTENSION_POINT_ID)) {
				String uniqueId;
				String namespaceName;
				int simpleIdStart = attrValue.lastIndexOf('.');
				if (simpleIdStart != -1 && extractNamespaces) {
					namespaceName = attrValue.substring(0, simpleIdStart);
					uniqueId = attrValue;
				} else {
					namespaceName = contribution.getDefaultNamespace();
					uniqueId = namespaceName + '.' + attrValue;
				}
				currentExtPoint.setUniqueIdentifier(uniqueId);
				currentExtPoint.setNamespace(namespaceName);

			} else if (attrName.equals(EXTENSION_POINT_SCHEMA))
				currentExtPoint.setSchema(attrValue);
			else
				unknownAttribute(attrName, EXTENSION_POINT);
		}
		if (currentExtPoint.getSimpleIdentifier() == null || currentExtPoint.getLabel() == null) {
			String attribute = currentExtPoint.getSimpleIdentifier() == null ? EXTENSION_POINT_ID : EXTENSION_POINT_NAME;
			missingAttribute(attribute, EXTENSION_POINT);
			stateStack.pop();
			stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
			return;
		}
		if (!objectManager.addExtensionPoint(currentExtPoint, true)) {
			// avoid adding extension point second time as it might cause
			// extensions associated with the existing extension point to
			// become inaccessible.
			if (registry.debug()) {
				String msg = NLS.bind(RegistryMessages.parse_duplicateExtensionPoint, currentExtPoint.getUniqueIdentifier(), contribution.getDefaultNamespace());
				registry.log(new Status(IStatus.ERROR, RegistryMessages.OWNER_NAME, 0, msg, null));
			}
			stateStack.pop();
			stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
			return;
		}
		if (currentExtPoint.getNamespace() == null)
			currentExtPoint.setNamespace(contribution.getDefaultNamespace());
		currentExtPoint.setContributorId(contribution.getContributorId());
		addedRegistryObjects.add(currentExtPoint);

		// Now populate the the vector just below us on the objectStack with this extension point
		scratchVectors[EXTENSION_POINT_INDEX].add(currentExtPoint);
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#startDocument()
	 */
	@Override
	public void startDocument() {
		stateStack.push(Integer.valueOf(INITIAL_STATE));
		for (int i = 0; i <= LAST_INDEX; i++) {
			scratchVectors[i] = new ArrayList<>();
		}
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
	 */
	@Override
	public void startElement(String uri, String elementName, String qName, Attributes attributes) {
		switch (stateStack.peek().intValue()) {
			case INITIAL_STATE :
				handleInitialState(elementName, attributes);
				break;
			case BUNDLE_STATE :
				handleBundleState(elementName, attributes);
				break;
			case BUNDLE_EXTENSION_POINT_STATE :
				handleExtensionPointState(elementName);
				break;
			case BUNDLE_EXTENSION_STATE :
			case CONFIGURATION_ELEMENT_STATE :
				handleExtensionState(elementName, attributes);
				break;
			default :
				stateStack.push(Integer.valueOf(IGNORED_ELEMENT_STATE));
				if (!compatibilityMode)
					internalError(NLS.bind(RegistryMessages.parse_unknownTopElement, elementName));
		}
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.helpers.DefaultHandler#warning(org.xml.sax.SAXParseException)
	 */
	@Override
	public void warning(SAXParseException ex) {
		logStatus(ex);
	}

	private void internalError(String message) {
		error(new Status(IStatus.WARNING, RegistryMessages.OWNER_NAME, PARSE_PROBLEM, message, null));
	}

	/* (non-Javadoc)
	 * @see org.xml.sax.ContentHandler#processingInstruction
	 * @since 3.0
	 */
	@Override
	public void processingInstruction(String target, String data) {
		// Since 3.0, a processing instruction of the form <?eclipse version="3.0"?> at
		// the start of the manifest file is used to indicate the plug-in manifest
		// schema version in effect. Pre-3.0 (i.e., 2.1) plug-in manifest files do not
		// have one of these, and this is how we can distinguish the manifest of a
		// pre-3.0 plug-in from a post-3.0 one (for compatibility transformations).
		if (target.equalsIgnoreCase("eclipse")) { //$NON-NLS-1$
			// just the presence of this processing instruction indicates that this
			// plug-in is at least 3.0
			schemaVersion = VERSION_3_0;
			StringTokenizer tokenizer = new StringTokenizer(data, "=\""); //$NON-NLS-1$
			while (tokenizer.hasMoreTokens()) {
				String token = tokenizer.nextToken();
				if (token.equalsIgnoreCase("version")) { //$NON-NLS-1$
					if (!tokenizer.hasMoreTokens()) {
						break;
					}
					schemaVersion = tokenizer.nextToken();
					break;
				}
			}
			initializeExtractNamespace();
		}
	}

	
Handles an error state specified by the status.  The collection of all logged status
objects can be accessed using getStatus().
Params:
error – a status detailing the error condition/**
	 * Handles an error state specified by the status.  The collection of all logged status
	 * objects can be accessed using <code>getStatus()</code>.
	 *
	 * @param error a status detailing the error condition
	 */
	public void error(IStatus error) {
		status.add(error);
	}

	protected String translate(String key) {
		return registry.translate(key, resources);
	}

	
Fixes up the extension declarations in the given pre-3.0 plug-in or fragment to compensate
for extension points that were renamed between release 2.1 and 3.0.
/**
	 * Fixes up the extension declarations in the given pre-3.0 plug-in or fragment to compensate
	 * for extension points that were renamed between release 2.1 and 3.0.
	 */
	private Extension[] fixRenamedExtensionPoints(Extension[] extensions) {
		if (extensions == null || versionAtLeast(VERSION_3_0) || RegistryProperties.getProperty(NO_EXTENSION_MUNGING) != null)
			return extensions;
		for (Extension extension : extensions) {
			String oldPointId = extension.getExtensionPointIdentifier();
			String newPointId = extensionPointMap.get(oldPointId);
			if (newPointId != null) {
				extension.setExtensionPointIdentifier(newPointId);
			}
		}
		return extensions;
	}

	
To preserve backward compatibility, we will only attempt to extract namespace form the name
if Eclipse version specified in the plugin.xml () is at least 3.2.
/**
	 * To preserve backward compatibility, we will only attempt to extract namespace form the name
	 * if Eclipse version specified in the plugin.xml (<?eclipse version="3.2"?>) is at least 3.2.
	 */
	private void initializeExtractNamespace() {
		extractNamespaces = Boolean.valueOf(versionAtLeast(VERSION_3_2)).booleanValue();
	}

	
Makes sense only for plugin.xml versions >= 3.0 (Eclipse version was introduced in 3.0).
Assumes that version is stored as "X1.X2.....XN" where X1 is a major version; X2 is a minor version
and so on.
/**
	 * Makes sense only for plugin.xml versions >= 3.0 (Eclipse version was introduced in 3.0).
	 * Assumes that version is stored as "X1.X2.....XN" where X1 is a major version; X2 is a minor version
	 * and so on.
	 */
	private boolean versionAtLeast(String testVersion) {
		if (schemaVersion == null)
			return false;

		StringTokenizer testVersionTokenizer = new StringTokenizer(testVersion, "."); //$NON-NLS-1$
		StringTokenizer schemaVersionTokenizer = new StringTokenizer(schemaVersion, "."); //$NON-NLS-1$
		while (testVersionTokenizer.hasMoreTokens() && schemaVersionTokenizer.hasMoreTokens()) {
			try {
				if (Integer.parseInt(schemaVersionTokenizer.nextToken()) < Integer.parseInt(testVersionTokenizer.nextToken()))
					return false;
			} catch (NumberFormatException e) {
				return false;
			}
		}
		return true;
	}
}