Copyright (c) 2000, 2016 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
    Serge Beauchamp (Freescale Semiconductor) - [229633] Project Path Variable Support
    Markus Schorn (Wind River) - [306575] Save snapshot location with project
    James Blackburn (Broadcom Corp.) - ongoing development
    Lars Vogel  - Bug 473427
    Mickael Istria (Red Hat Inc.) - Bug 488937
/*******************************************************************************
 * Copyright (c) 2000, 2016 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
 *     Serge Beauchamp (Freescale Semiconductor) - [229633] Project Path Variable Support
 *     Markus Schorn (Wind River) - [306575] Save snapshot location with project
 *     James Blackburn (Broadcom Corp.) - ongoing development
 *     Lars Vogel <Lars.Vogel@vogella.com> - Bug 473427
 *     Mickael Istria (Red Hat Inc.) - Bug 488937
 *******************************************************************************/
package org.eclipse.core.internal.resources;

import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.*;
import javax.xml.parsers.*;
import org.eclipse.core.filesystem.URIUtil;
import org.eclipse.core.internal.events.BuildCommand;
import org.eclipse.core.internal.localstore.SafeFileInputStream;
import org.eclipse.core.internal.utils.Messages;
import org.eclipse.core.internal.utils.Policy;
import org.eclipse.core.resources.*;
import org.eclipse.core.runtime.*;
import org.eclipse.osgi.util.NLS;
import org.xml.sax.*;
import org.xml.sax.helpers.DefaultHandler;

Reads serialized project descriptions.
Note: Suppress warnings on whole class because of unusual use of objectStack.
/**
 * Reads serialized project descriptions.
 *
 * Note: Suppress warnings on whole class because of unusual use of objectStack.
 */
@SuppressWarnings({"unchecked"})
public class ProjectDescriptionReader extends DefaultHandler implements IModelObjectConstants {

	//states
	protected static final int S_BUILD_COMMAND = 0;
	protected static final int S_BUILD_COMMAND_ARGUMENTS = 1;
	protected static final int S_BUILD_COMMAND_NAME = 2;
	protected static final int S_BUILD_COMMAND_TRIGGERS = 3;
	protected static final int S_BUILD_SPEC = 4;
	protected static final int S_DICTIONARY = 5;
	protected static final int S_DICTIONARY_KEY = 6;
	protected static final int S_DICTIONARY_VALUE = 7;
	protected static final int S_INITIAL = 8;
	protected static final int S_LINK = 9;
	protected static final int S_LINK_LOCATION = 10;
	protected static final int S_LINK_LOCATION_URI = 11;
	protected static final int S_LINK_PATH = 12;
	protected static final int S_LINK_TYPE = 13;
	protected static final int S_LINKED_RESOURCES = 14;
	protected static final int S_NATURE_NAME = 15;
	protected static final int S_NATURES = 16;
	protected static final int S_PROJECT_COMMENT = 17;
	protected static final int S_PROJECT_DESC = 18;
	protected static final int S_PROJECT_NAME = 19;
	protected static final int S_PROJECTS = 20;
	protected static final int S_REFERENCED_PROJECT_NAME = 21;

	protected static final int S_FILTERED_RESOURCES = 23;
	protected static final int S_FILTER = 24;
	protected static final int S_FILTER_ID = 25;
	protected static final int S_FILTER_PATH = 26;
	protected static final int S_FILTER_TYPE = 27;

	protected static final int S_MATCHER = 28;
	protected static final int S_MATCHER_ID = 29;
	protected static final int S_MATCHER_ARGUMENTS = 30;

	protected static final int S_VARIABLE_LIST = 31;
	protected static final int S_VARIABLE = 32;
	protected static final int S_VARIABLE_NAME = 33;
	protected static final int S_VARIABLE_VALUE = 34;

	protected static final int S_SNAPSHOT_LOCATION = 35;

	
Singleton sax parser factory
/**
	 * Singleton sax parser factory
	 */
	private static SAXParserFactory singletonParserFactory;

	
Singleton sax parser
/**
	 * Singleton sax parser
	 */
	private static SAXParser singletonParser;

	protected final StringBuilder charBuffer = new StringBuilder();

	protected Stack<Object> objectStack;
	protected MultiStatus problems;

	
The project we are reading the description for, or null if unknown.
/**
	 * The project we are reading the description for, or null if unknown.
	 */
	private final IProject project;
	// The project description we are creating.
	ProjectDescription projectDescription = null;

	protected int state = S_INITIAL;

	
Returns the SAXParser to use when parsing project description files.
Throws:
ParserConfigurationException – 
SAXException – /**
	 * Returns the SAXParser to use when parsing project description files.
	 * @throws ParserConfigurationException
	 * @throws SAXException
	 */
	private static synchronized SAXParser createParser() throws ParserConfigurationException, SAXException {
		//the parser can't be used concurrently, so only use singleton when workspace is locked
		if (!isWorkspaceLocked())
			return createParserFactory().newSAXParser();
		if (singletonParser == null) {
			singletonParser = createParserFactory().newSAXParser();
		}
		return singletonParser;
	}

	
Returns the SAXParserFactory to use when parsing project description files.
Throws:
ParserConfigurationException – /**
	 * Returns the SAXParserFactory to use when parsing project description files.
	 * @throws ParserConfigurationException
	 */
	private static synchronized SAXParserFactory createParserFactory() throws ParserConfigurationException {
		if (singletonParserFactory == null) {
			singletonParserFactory = SAXParserFactory.newInstance();
			singletonParserFactory.setNamespaceAware(true);
			try {
				singletonParserFactory.setFeature("http://xml.org/sax/features/string-interning", true); //$NON-NLS-1$
			} catch (SAXException e) {
				// In case support for this feature is removed
			}
		}
		return singletonParserFactory;
	}

	private static boolean isWorkspaceLocked() {
		try {
			return ((Workspace) ResourcesPlugin.getWorkspace()).getWorkManager().isLockAlreadyAcquired();
		} catch (CoreException e) {
			return false;
		}
	}

	public ProjectDescriptionReader() {
		this.project = null;
	}

	public ProjectDescriptionReader(IProject project) {
		this.project = project;
	}

	
See Also:
characters.characters(char[], int, int)/**
	 * @see ContentHandler#characters(char[], int, int)
	 */
	@Override
	public void characters(char[] chars, int offset, int length) {
		//accumulate characters and process them when endElement is reached
		charBuffer.append(chars, offset, length);
	}

	
End of an element that is part of a build command
/**
	 * End of an element that is part of a build command
	 */
	private void endBuildCommandElement(String elementName) {
		if (elementName.equals(BUILD_COMMAND)) {
			// Pop this BuildCommand off the stack.
			BuildCommand command = (BuildCommand) objectStack.pop();
			// Add this BuildCommand to a array list of BuildCommands.
			ArrayList<BuildCommand> commandList = (ArrayList<BuildCommand>) objectStack.peek();
			commandList.add(command);
			state = S_BUILD_SPEC;
		}
	}

	
End of an element that is part of a build spec
/**
	 * End of an element that is part of a build spec
	 */
	private void endBuildSpecElement(String elementName) {
		if (elementName.equals(BUILD_SPEC)) {
			// Pop off the array list of BuildCommands and add them to the
			// ProjectDescription which is the next thing on the stack.
			ArrayList<ICommand> commands = (ArrayList<ICommand>) objectStack.pop();
			state = S_PROJECT_DESC;
			if (commands.isEmpty())
				return;
			ICommand[] commandArray = commands.toArray(new ICommand[commands.size()]);
			projectDescription.setBuildSpec(commandArray);
		}
	}

	
End a build triggers element and set the triggers for the current
build command element.
/**
	 * End a build triggers element and set the triggers for the current
	 * build command element.
	 */
	private void endBuildTriggersElement(String elementName) {
		if (elementName.equals(BUILD_TRIGGERS)) {
			state = S_BUILD_COMMAND;
			BuildCommand command = (BuildCommand) objectStack.peek();
			//presence of this element indicates the builder is configurable
			command.setConfigurable(true);
			//clear all existing values
			command.setBuilding(IncrementalProjectBuilder.AUTO_BUILD, false);
			command.setBuilding(IncrementalProjectBuilder.CLEAN_BUILD, false);
			command.setBuilding(IncrementalProjectBuilder.FULL_BUILD, false);
			command.setBuilding(IncrementalProjectBuilder.INCREMENTAL_BUILD, false);

			//set new values according to value in the triggers element
			StringTokenizer tokens = new StringTokenizer(charBuffer.toString(), ","); //$NON-NLS-1$
			while (tokens.hasMoreTokens()) {
				String next = tokens.nextToken();
				if (next.toLowerCase().equals(TRIGGER_AUTO)) {
					command.setBuilding(IncrementalProjectBuilder.AUTO_BUILD, true);
				} else if (next.toLowerCase().equals(TRIGGER_CLEAN)) {
					command.setBuilding(IncrementalProjectBuilder.CLEAN_BUILD, true);
				} else if (next.toLowerCase().equals(TRIGGER_FULL)) {
					command.setBuilding(IncrementalProjectBuilder.FULL_BUILD, true);
				} else if (next.toLowerCase().equals(TRIGGER_INCREMENTAL)) {
					command.setBuilding(IncrementalProjectBuilder.INCREMENTAL_BUILD, true);
				}
			}
		}
	}

	
End of a dictionary element
/**
	 * End of a dictionary element
	 */
	private void endDictionary(String elementName) {
		if (elementName.equals(DICTIONARY)) {
			// Pick up the value and then key off the stack and add them
			// to the HashMap which is just below them on the stack.
			// Leave the HashMap on the stack to pick up more key/value
			// pairs if they exist.
			String value = (String) objectStack.pop();
			String key = (String) objectStack.pop();
			((HashMap<String, String>) objectStack.peek()).put(key, value);
			state = S_BUILD_COMMAND_ARGUMENTS;
		}
	}

	private void endDictionaryKey(String elementName) {
		if (elementName.equals(KEY)) {
			// There is a value place holder on the top of the stack and
			// a key place holder just below it.
			String value = (String) objectStack.pop();
			String oldKey = (String) objectStack.pop();
			String newKey = charBuffer.toString();
			if (oldKey != null && oldKey.length() != 0) {
				parseProblem(NLS.bind(Messages.projRead_whichKey, oldKey, newKey));
				objectStack.push(oldKey);
			} else {
				objectStack.push(newKey);
			}
			//push back the dictionary value
			objectStack.push(value);
			state = S_DICTIONARY;
		}
	}

	private void endDictionaryValue(String elementName) {
		if (elementName.equals(VALUE)) {
			String newValue = charBuffer.toString();
			// There is a value place holder on the top of the stack
			String oldValue = (String) objectStack.pop();
			if (oldValue != null && oldValue.length() != 0) {
				parseProblem(NLS.bind(Messages.projRead_whichValue, oldValue, newValue));
				objectStack.push(oldValue);
			} else {
				objectStack.push(newValue);
			}
			state = S_DICTIONARY;
		}
	}

	
See Also:
endElement.endElement(String, String, String)/**
	 * @see ContentHandler#endElement(String, String, String)
	 */
	@Override
	public void endElement(String uri, String elementName, String qname) {
		switch (state) {
			case S_PROJECT_DESC :
				// Don't think we need to do anything here.
				break;
			case S_PROJECT_NAME :
				if (elementName.equals(NAME)) {
					// Project names cannot have leading/trailing whitespace
					// as they are IResource names.
					projectDescription.setName(charBuffer.toString().trim());
					state = S_PROJECT_DESC;
				}
				break;
			case S_PROJECTS :
				if (elementName.equals(PROJECTS)) {
					endProjectsElement(elementName);
					state = S_PROJECT_DESC;
				}
				break;
			case S_DICTIONARY :
				endDictionary(elementName);
				break;
			case S_BUILD_COMMAND_ARGUMENTS :
				if (elementName.equals(ARGUMENTS)) {
					// There is a hashmap on the top of the stack with the
					// arguments (if any).
					HashMap<String, String> dictionaryArgs = (HashMap<String, String>) objectStack.pop();
					state = S_BUILD_COMMAND;
					if (dictionaryArgs.isEmpty())
						break;
					// Below the hashMap on the stack, there is a BuildCommand.
					((BuildCommand) objectStack.peek()).setArguments(dictionaryArgs);
				}
				break;
			case S_BUILD_COMMAND :
				endBuildCommandElement(elementName);
				break;
			case S_BUILD_SPEC :
				endBuildSpecElement(elementName);
				break;
			case S_BUILD_COMMAND_TRIGGERS :
				endBuildTriggersElement(elementName);
				break;
			case S_NATURES :
				endNaturesElement(elementName);
				break;
			case S_LINK :
				endLinkElement(elementName);
				break;
			case S_LINKED_RESOURCES :
				endLinkedResourcesElement(elementName);
				break;
			case S_VARIABLE :
				endVariableElement(elementName);
				break;
			case S_FILTER :
				endFilterElement(elementName);
				break;
			case S_FILTERED_RESOURCES :
				endFilteredResourcesElement(elementName);
				break;
			case S_VARIABLE_LIST :
				endVariableListElement(elementName);
				break;
			case S_PROJECT_COMMENT :
				if (elementName.equals(COMMENT)) {
					projectDescription.setComment(charBuffer.toString());
					state = S_PROJECT_DESC;
				}
				break;
			case S_REFERENCED_PROJECT_NAME :
				if (elementName.equals(PROJECT)) {
					//top of stack is list of project references
					// Referenced projects are just project names and, therefore,
					// are also IResource names and cannot have leading/trailing
					// whitespace.
					((ArrayList<String>) objectStack.peek()).add(charBuffer.toString().trim());
					state = S_PROJECTS;
				}
				break;
			case S_BUILD_COMMAND_NAME :
				if (elementName.equals(NAME)) {
					//top of stack is the build command
					// A build command name is an extension id and
					// cannot have leading/trailing whitespace.
					((BuildCommand) objectStack.peek()).setName(charBuffer.toString().trim());
					state = S_BUILD_COMMAND;
				}
				break;
			case S_DICTIONARY_KEY :
				endDictionaryKey(elementName);
				break;
			case S_DICTIONARY_VALUE :
				endDictionaryValue(elementName);
				break;
			case S_NATURE_NAME :
				if (elementName.equals(NATURE)) {
					//top of stack is list of nature names
					// A nature name is an extension id and cannot
					// have leading/trailing whitespace.
					((ArrayList<String>) objectStack.peek()).add(charBuffer.toString().trim());
					state = S_NATURES;
				}
				break;
			case S_LINK_PATH :
				endLinkPath(elementName);
				break;
			case S_LINK_TYPE :
				endLinkType(elementName);
				break;
			case S_LINK_LOCATION :
				endLinkLocation(elementName);
				break;
			case S_LINK_LOCATION_URI :
				endLinkLocationURI(elementName);
				break;
			case S_FILTER_ID :
				endFilterId(elementName);
				break;
			case S_FILTER_PATH :
				endFilterPath(elementName);
				break;
			case S_FILTER_TYPE :
				endFilterType(elementName);
				break;
			case S_MATCHER :
				endMatcherElement(elementName);
				break;
			case S_MATCHER_ID :
				endMatcherID(elementName);
				break;
			case S_MATCHER_ARGUMENTS :
				endMatcherArguments(elementName);
				break;
			case S_VARIABLE_NAME :
				endVariableName(elementName);
				break;
			case S_VARIABLE_VALUE :
				endVariableValue(elementName);
				break;
			case S_SNAPSHOT_LOCATION :
				endSnapshotLocation(elementName);
				break;
		}
		charBuffer.setLength(0);
	}

	
End this group of linked resources and add them to the project description.
/**
	 * End this group of linked resources and add them to the project description.
	 */
	private void endLinkedResourcesElement(String elementName) {
		if (elementName.equals(LINKED_RESOURCES)) {
			HashMap<IPath, LinkDescription> linkedResources = (HashMap<IPath, LinkDescription>) objectStack.pop();
			state = S_PROJECT_DESC;
			if (linkedResources.isEmpty())
				return;
			projectDescription.setLinkDescriptions(linkedResources);
		}
	}

	
End this group of linked resources and add them to the project description.
/**
	 * End this group of linked resources and add them to the project description.
	 */
	private void endFilteredResourcesElement(String elementName) {
		if (elementName.equals(FILTERED_RESOURCES)) {
			HashMap<IPath, LinkedList<FilterDescription>> filteredResources = (HashMap<IPath, LinkedList<FilterDescription>>) objectStack.pop();
			state = S_PROJECT_DESC;
			if (filteredResources.isEmpty())
				return;
			projectDescription.setFilterDescriptions(filteredResources);
		}
	}

	
End this group of group resources and add them to the project
description.
/**
	 * End this group of group resources and add them to the project
	 * description.
	 */
	private void endVariableListElement(String elementName) {
		if (elementName.equals(VARIABLE_LIST)) {
			HashMap<String, VariableDescription> variableList = (HashMap<String, VariableDescription>) objectStack.pop();
			state = S_PROJECT_DESC;
			if (variableList.isEmpty())
				return;
			projectDescription.setVariableDescriptions(variableList);
		}
	}

	
End a single linked resource and add it to the HashMap.
/**
	 * End a single linked resource and add it to the HashMap.
	 */
	private void endLinkElement(String elementName) {
		if (elementName.equals(LINK)) {
			state = S_LINKED_RESOURCES;
			// Pop off the link description
			LinkDescription link = (LinkDescription) objectStack.pop();
			// Make sure that you have something reasonable
			IPath path = link.getProjectRelativePath();
			int type = link.getType();
			URI location = link.getLocationURI();
			if (location == null) {
				parseProblem(NLS.bind(Messages.projRead_badLinkLocation, path, Integer.toString(type)));
				return;
			}
			if ((path == null) || path.segmentCount() == 0) {
				parseProblem(NLS.bind(Messages.projRead_emptyLinkName, Integer.toString(type), location));
				return;
			}
			if (type == -1) {
				parseProblem(NLS.bind(Messages.projRead_badLinkType, path, location));
				return;
			}

			// The HashMap of linked resources is the next thing on the stack
			((HashMap<IPath, LinkDescription>) objectStack.peek()).put(link.getProjectRelativePath(), link);
		}
	}

	private void endMatcherElement(String elementName) {
		if (elementName.equals(MATCHER)) {
			// Pop off an array (Object[2]) containing the matcher id and arguments.
			Object[] matcher = (Object[]) objectStack.pop();
			// Make sure that you have something reasonable
			String id = (String) matcher[0];
			// the id can't be null
			if (id == null) {
				parseProblem(NLS.bind(Messages.projRead_badFilterID, null));
				return;
			}

			if (objectStack.peek() instanceof ArrayList) {
				state = S_MATCHER_ARGUMENTS;
				// The ArrayList of matchers is the next thing on the stack
				ArrayList<FileInfoMatcherDescription> list = ((ArrayList<FileInfoMatcherDescription>) objectStack.peek());
				list.add(new FileInfoMatcherDescription((String) matcher[0], matcher[1]));
			}

			if (objectStack.peek() instanceof FilterDescription) {
				state = S_FILTER;
				FilterDescription d = ((FilterDescription) objectStack.peek());
				d.setFileInfoMatcherDescription(new FileInfoMatcherDescription((String) matcher[0], matcher[1]));
			}
		}
	}

	
End a single filtered resource and add it to the HashMap.
/**
	 * End a single filtered resource and add it to the HashMap.
	 */
	private void endFilterElement(String elementName) {
		if (elementName.equals(FILTER)) {
			// Pop off the filter description
			FilterDescription filter = (FilterDescription) objectStack.pop();
			if (project != null) {
				// Make sure that you have something reasonable
				IPath path = filter.getResource().getProjectRelativePath();
				int type = filter.getType();
				// arguments can be null
				if (path == null) {
					parseProblem(NLS.bind(Messages.projRead_emptyFilterName, Integer.toString(type)));
					return;
				}
				if (type == -1) {
					parseProblem(NLS.bind(Messages.projRead_badFilterType, path));
					return;
				}

				// The HashMap of filtered resources is the next thing on the stack
				HashMap<IPath, LinkedList<FilterDescription>> map = ((HashMap<IPath, LinkedList<FilterDescription>>) objectStack.peek());
				LinkedList<FilterDescription> list = map.get(filter.getResource().getProjectRelativePath());
				if (list == null) {
					list = new LinkedList<>();
					map.put(filter.getResource().getProjectRelativePath(), list);
				}
				list.add(filter);
			} else {
				// if the project is null, that means that we're loading a project description to retrieve
				// some meta data only.
				String key = ""; // an empty key; //$NON-NLS-1$
				HashMap<String, LinkedList<FilterDescription>> map = ((HashMap<String, LinkedList<FilterDescription>>) objectStack.peek());
				LinkedList<FilterDescription> list = map.get(key);
				if (list == null) {
					list = new LinkedList<>();
					map.put(key, list);
				}
				list.add(filter);
			}
			state = S_FILTERED_RESOURCES;
		}
	}

	
End a single group resource and add it to the HashMap.
/**
	 * End a single group resource and add it to the HashMap.
	 */
	private void endVariableElement(String elementName) {
		if (elementName.equals(VARIABLE)) {
			state = S_VARIABLE_LIST;
			// Pop off the link description
			VariableDescription desc = (VariableDescription) objectStack.pop();
			// Make sure that you have something reasonable
			if (desc.getName().length() == 0) {
				parseProblem(NLS.bind(Messages.projRead_emptyVariableName, project.getName()));
				return;
			}

			// The HashMap of variables is the next thing on the stack
			((HashMap<String, VariableDescription>) objectStack.peek()).put(desc.getName(), desc);
		}
	}

	
For backwards compatibility, link locations in the local file system are represented
in the project description under the "location" tag.
Params:
elementName – /**
	 * For backwards compatibility, link locations in the local file system are represented
	 * in the project description under the "location" tag.
	 * @param elementName
	 */
	private void endLinkLocation(String elementName) {
		if (elementName.equals(LOCATION)) {
			// A link location is an URI.  URIs cannot have leading/trailing whitespace
			String newLocation = charBuffer.toString().trim();
			// objectStack has a LinkDescription on it. Set the type on this LinkDescription.
			URI oldLocation = ((LinkDescription) objectStack.peek()).getLocationURI();
			if (oldLocation != null) {
				parseProblem(NLS.bind(Messages.projRead_badLocation, oldLocation, newLocation));
			} else {
				((LinkDescription) objectStack.peek()).setLocationURI(URIUtil.toURI(Path.fromPortableString(newLocation)));
			}
			state = S_LINK;
		}
	}

	
Link locations that are not stored in the local file system are represented
in the project description under the "locationURI" tag.
Params:
elementName – /**
	 * Link locations that are not stored in the local file system are represented
	 * in the project description under the "locationURI" tag.
	 * @param elementName
	 */
	private void endLinkLocationURI(String elementName) {
		if (elementName.equals(LOCATION_URI)) {
			// A link location is an URI.  URIs cannot have leading/trailing whitespace
			String newLocation = charBuffer.toString().trim();
			// objectStack has a LinkDescription on it. Set the type on this LinkDescription.
			URI oldLocation = ((LinkDescription) objectStack.peek()).getLocationURI();
			if (oldLocation != null) {
				parseProblem(NLS.bind(Messages.projRead_badLocation, oldLocation, newLocation));
			} else {
				try {
					((LinkDescription) objectStack.peek()).setLocationURI(new URI(newLocation));
				} catch (URISyntaxException e) {
					String msg = Messages.projRead_failureReadingProjectDesc;
					problems.add(new Status(IStatus.WARNING, ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, msg, e));
				}
			}
			state = S_LINK;
		}
	}

	private void endLinkPath(String elementName) {
		if (elementName.equals(NAME)) {
			IPath newPath = new Path(charBuffer.toString());
			// objectStack has a LinkDescription on it. Set the name
			// on this LinkDescription.
			IPath oldPath = ((LinkDescription) objectStack.peek()).getProjectRelativePath();
			if (oldPath.segmentCount() != 0) {
				parseProblem(NLS.bind(Messages.projRead_badLinkName, oldPath, newPath));
			} else {
				((LinkDescription) objectStack.peek()).setPath(newPath);
			}
			state = S_LINK;
		}
	}

	private void endMatcherID(String elementName) {
		if (elementName.equals(ID)) {
			// The matcher id is String.
			String newID = charBuffer.toString().trim();
			// objectStack has an array (Object[2]) on it for the matcher id and arguments.
			String oldID = (String) ((Object[]) objectStack.peek())[0];
			if (oldID != null) {
				parseProblem(NLS.bind(Messages.projRead_badID, oldID, newID));
			} else {
				((Object[]) objectStack.peek())[0] = newID;
			}
			state = S_MATCHER;
		}
	}

	private void endMatcherArguments(String elementName) {
		if (elementName.equals(ARGUMENTS)) {
			ArrayList<FileInfoMatcherDescription> matchers = (ArrayList<FileInfoMatcherDescription>) objectStack.pop();
			Object newArguments = charBuffer.toString();

			if (matchers.size() > 0)
				newArguments = matchers.toArray(new FileInfoMatcherDescription[matchers.size()]);

			// objectStack has an array (Object[2]) on it for the matcher id and arguments.
			String oldArguments = (String) ((Object[]) objectStack.peek())[1];
			if (oldArguments != null) {
				parseProblem(NLS.bind(Messages.projRead_badArguments, oldArguments, newArguments));
			} else
				((Object[]) objectStack.peek())[1] = newArguments;
			state = S_MATCHER;
		}
	}

	private void endFilterId(String elementName) {
		if (elementName.equals(ID)) {
			Long newId = Long.parseLong(charBuffer.toString());
			// objectStack has a FilterDescription on it. Set the name
			// on this FilterDescription.
			long oldId = ((FilterDescription) objectStack.peek()).getId();
			if (oldId != 0) {
				parseProblem(NLS.bind(Messages.projRead_badFilterName, oldId, newId));
			} else {
				((FilterDescription) objectStack.peek()).setId(newId.longValue());
			}
			state = S_FILTER;
		}
	}

	private void endFilterPath(String elementName) {
		if (elementName.equals(NAME)) {
			IPath newPath = new Path(charBuffer.toString());
			// objectStack has a FilterDescription on it. Set the name
			// on this FilterDescription.
			IResource oldResource = ((FilterDescription) objectStack.peek()).getResource();
			if (oldResource != null) {
				parseProblem(NLS.bind(Messages.projRead_badFilterName, oldResource.getProjectRelativePath(), newPath));
			} else {
				if (project != null) {
					((FilterDescription) objectStack.peek()).setResource(newPath.isEmpty() ? (IResource) project : project.getFolder(newPath));
				} else {
					// if the project is null, that means that we're loading a project description to retrieve
					// some meta data only.
					((FilterDescription) objectStack.peek()).setResource(null);
				}
			}
			state = S_FILTER;
		}
	}

	private void endFilterType(String elementName) {
		if (elementName.equals(TYPE)) {
			int newType = -1;
			try {
				// parseInt expects a string containing only numerics
				// or a leading '-'.  Ensure there is no leading/trailing
				// whitespace.
				newType = Integer.parseInt(charBuffer.toString().trim());
			} catch (NumberFormatException e) {
				log(e);
			}
			// objectStack has a FilterDescription on it. Set the type
			// on this FilterDescription.
			int oldType = ((FilterDescription) objectStack.peek()).getType();
			if (oldType != -1) {
				parseProblem(NLS.bind(Messages.projRead_badFilterType2, Integer.toString(oldType), Integer.toString(newType)));
			} else {
				((FilterDescription) objectStack.peek()).setType(newType);
			}
			state = S_FILTER;
		}
	}

	private void endVariableName(String elementName) {
		if (elementName.equals(NAME)) {
			String value = charBuffer.toString();
			// objectStack has a VariableDescription on it. Set the value
			// on this ValueDescription.
			((VariableDescription) objectStack.peek()).setName(value);
			state = S_VARIABLE;
		}
	}

	private void endVariableValue(String elementName) {
		if (elementName.equals(VALUE)) {
			String value = charBuffer.toString();
			// objectStack has a VariableDescription on it. Set the value
			// on this ValueDescription.
			((VariableDescription) objectStack.peek()).setValue(value);
			state = S_VARIABLE;
		}
	}

	private void endLinkType(String elementName) {
		if (elementName.equals(TYPE)) {
			//FIXME we should handle this case by removing the entire link
			//for now we default to a file link
			int newType = IResource.FILE;
			try {
				// parseInt expects a string containing only numerics
				// or a leading '-'.  Ensure there is no leading/trailing
				// whitespace.
				newType = Integer.parseInt(charBuffer.toString().trim());
			} catch (NumberFormatException e) {
				log(e);
			}
			// objectStack has a LinkDescription on it. Set the type
			// on this LinkDescription.
			int oldType = ((LinkDescription) objectStack.peek()).getType();
			if (oldType != -1) {
				parseProblem(NLS.bind(Messages.projRead_badLinkType2, Integer.toString(oldType), Integer.toString(newType)));
			} else {
				((LinkDescription) objectStack.peek()).setType(newType);
			}
			state = S_LINK;
		}
	}

	
End of an element that is part of a nature list
/**
	 * End of an element that is part of a nature list
	 */
	private void endNaturesElement(String elementName) {
		if (elementName.equals(NATURES)) {
			// Pop the array list of natures off the stack
			ArrayList<String> natures = (ArrayList<String>) objectStack.pop();
			state = S_PROJECT_DESC;
			if (natures.isEmpty())
				return;
			String[] natureNames = natures.toArray(new String[natures.size()]);
			projectDescription.setNatureIds(natureNames);
		}
	}

	
End of an element that is part of a project references list
/**
	 * End of an element that is part of a project references list
	 */
	private void endProjectsElement(String elementName) {
		// Pop the array list that contains all the referenced project names
		ArrayList<String> referencedProjects = (ArrayList<String>) objectStack.pop();
		if (referencedProjects.isEmpty())
			// Don't bother adding an empty group of referenced projects to the
			// project descriptor.
			return;
		IWorkspaceRoot root = ResourcesPlugin.getWorkspace().getRoot();
		IProject[] projects = new IProject[referencedProjects.size()];
		for (int i = 0; i < projects.length; i++) {
			projects[i] = root.getProject(referencedProjects.get(i));
		}
		projectDescription.setReferencedProjects(projects);
	}

	private void endSnapshotLocation(String elementName) {
		if (elementName.equals(SNAPSHOT_LOCATION)) {
			String location = charBuffer.toString().trim();
			try {
				projectDescription.setSnapshotLocationURI(new URI(location));
			} catch (URISyntaxException e) {
				String msg = NLS.bind(Messages.projRead_badSnapshotLocation, location);
				problems.add(new Status(IStatus.WARNING, ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, msg, e));
			}
			state = S_PROJECT_DESC;
		}
	}

	
See Also:
error.error(SAXParseException)/**
	 * @see ErrorHandler#error(SAXParseException)
	 */
	@Override
	public void error(SAXParseException error) {
		log(error);
	}

	
See Also:
fatalError.fatalError(SAXParseException)/**
	 * @see ErrorHandler#fatalError(SAXParseException)
	 */
	@Override
	public void fatalError(SAXParseException error) throws SAXException {
		// ensure a null value is not passed as message to Status constructor (bug 42782)
		String message = error.getMessage();
		if (project != null)
			message = NLS.bind(Messages.resources_readMeta, project.getName());
		problems.add(new Status(IStatus.ERROR, ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, message == null ? "" : message, error)); //$NON-NLS-1$
		throw error;
	}

	protected void log(Exception ex) {
		String message = ex.getMessage();
		if (project != null)
			message = NLS.bind(Messages.resources_readMeta, project.getName());
		problems.add(new Status(IStatus.WARNING, ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, message == null ? "" : message, ex)); //$NON-NLS-1$
	}

	private void parseProblem(String errorMessage) {
		problems.add(new Status(IStatus.WARNING, ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, errorMessage, null));
	}

	private void parseProjectDescription(String elementName) {
		if (elementName.equals(NAME)) {
			state = S_PROJECT_NAME;
			return;
		}
		if (elementName.equals(COMMENT)) {
			state = S_PROJECT_COMMENT;
			return;
		}
		if (elementName.equals(PROJECTS)) {
			state = S_PROJECTS;
			// Push an array list on the object stack to hold the name
			// of all the referenced projects.  This array list will be
			// popped off the stack, massaged into the right format
			// and added to the project description when we hit the
			// end element for PROJECTS.
			objectStack.push(new ArrayList<String>());
			return;
		}
		if (elementName.equals(BUILD_SPEC)) {
			state = S_BUILD_SPEC;
			// Push an array list on the object stack to hold the build commands
			// for this build spec.  This array list will be popped off the stack,
			// massaged into the right format and added to the project's build
			// spec when we hit the end element for BUILD_SPEC.
			objectStack.push(new ArrayList<ICommand>());
			return;
		}
		if (elementName.equals(NATURES)) {
			state = S_NATURES;
			// Push an array list to hold all the nature names.
			objectStack.push(new ArrayList<String>());
			return;
		}
		if (elementName.equals(LINKED_RESOURCES)) {
			// Push a HashMap to collect all the links.
			objectStack.push(new HashMap<IPath, LinkDescription>());
			state = S_LINKED_RESOURCES;
			return;
		}
		if (elementName.equals(FILTERED_RESOURCES)) {
			// Push a HashMap to collect all the filters.
			objectStack.push(new HashMap<IPath, LinkedList<FilterDescription>>());
			state = S_FILTERED_RESOURCES;
			return;
		}
		if (elementName.equals(VARIABLE_LIST)) {
			// Push a HashMap to collect all the variables.
			objectStack.push(new HashMap<String, VariableDescription>());
			state = S_VARIABLE_LIST;
			return;
		}
		if (elementName.equals(SNAPSHOT_LOCATION)) {
			state = S_SNAPSHOT_LOCATION;
			return;
		}
	}

	public ProjectDescription read(InputSource input) {
		problems = new MultiStatus(ResourcesPlugin.PI_RESOURCES, IResourceStatus.FAILED_READ_METADATA, Messages.projRead_failureReadingProjectDesc, null);
		objectStack = new Stack<>();
		state = S_INITIAL;
		try {
			createParser().parse(input, this);
		} catch (ParserConfigurationException e) {
			log(e);
		} catch (IOException e) {
			log(e);
		} catch (SAXException e) {
			log(e);
		}

		if (projectDescription != null && projectDescription.getName() == null)
			parseProblem(Messages.projRead_missingProjectName);

		switch (problems.getSeverity()) {
			case IStatus.ERROR :
				Policy.log(problems);
				return null;
			case IStatus.WARNING :
			case IStatus.INFO :
				Policy.log(problems);
			case IStatus.OK :
			default :
				return projectDescription;
		}
	}

	
Reads and returns a project description stored at the given location
/**
	 * Reads and returns a project description stored at the given location
	 */
	public ProjectDescription read(IPath location) throws IOException {
		try (
			BufferedInputStream file = new BufferedInputStream(new FileInputStream(location.toFile()));
		) {
			return read(new InputSource(file));
		}
	}

	
Reads and returns a project description stored at the given location, or
temporary location.
/**
	 * Reads and returns a project description stored at the given location, or
	 * temporary location.
	 */
	public ProjectDescription read(IPath location, IPath tempLocation) throws IOException {
		try (
			SafeFileInputStream file = new SafeFileInputStream(location.toOSString(), tempLocation.toOSString());
		) {
			return read(new InputSource(file));
		}
	}

	
See Also:
startElement.startElement(String, String, String, Attributes)/**
	 * @see ContentHandler#startElement(String, String, String, Attributes)
	 */
	@Override
	public void startElement(String uri, String elementName, String qname, Attributes attributes) throws SAXException {
		//clear the character buffer at the start of every element
		charBuffer.setLength(0);
		switch (state) {
			case S_INITIAL :
				if (elementName.equals(PROJECT_DESCRIPTION)) {
					state = S_PROJECT_DESC;
					projectDescription = new ProjectDescription();
				} else {
					throw (new SAXException(NLS.bind(Messages.projRead_notProjectDescription, elementName)));
				}
				break;
			case S_PROJECT_DESC :
				parseProjectDescription(elementName);
				break;
			case S_PROJECTS :
				if (elementName.equals(PROJECT)) {
					state = S_REFERENCED_PROJECT_NAME;
				}
				break;
			case S_BUILD_SPEC :
				if (elementName.equals(BUILD_COMMAND)) {
					state = S_BUILD_COMMAND;
					objectStack.push(new BuildCommand());
				}
				break;
			case S_BUILD_COMMAND :
				if (elementName.equals(NAME)) {
					state = S_BUILD_COMMAND_NAME;
				} else if (elementName.equals(BUILD_TRIGGERS)) {
					state = S_BUILD_COMMAND_TRIGGERS;
				} else if (elementName.equals(ARGUMENTS)) {
					state = S_BUILD_COMMAND_ARGUMENTS;
					// Push a HashMap to hold all the key/value pairs which
					// will become the argument list.
					objectStack.push(new HashMap<String, String>());
				}
				break;
			case S_BUILD_COMMAND_ARGUMENTS :
				if (elementName.equals(DICTIONARY)) {
					state = S_DICTIONARY;
					// Push 2 strings for the key/value pair to be read
					objectStack.push(""); // key //$NON-NLS-1$
					objectStack.push(""); // value //$NON-NLS-1$
				}
				break;
			case S_DICTIONARY :
				if (elementName.equals(KEY)) {
					state = S_DICTIONARY_KEY;
				} else if (elementName.equals(VALUE)) {
					state = S_DICTIONARY_VALUE;
				}
				break;
			case S_NATURES :
				if (elementName.equals(NATURE)) {
					state = S_NATURE_NAME;
				}
				break;
			case S_LINKED_RESOURCES :
				if (elementName.equals(LINK)) {
					state = S_LINK;
					// Push place holders for the name, type and location of
					// this link.
					objectStack.push(new LinkDescription());
				}
				break;
			case S_VARIABLE_LIST :
				if (elementName.equals(VARIABLE)) {
					state = S_VARIABLE;
					// Push place holders for the name, type and location of
					// this link.
					objectStack.push(new VariableDescription());
				}
				break;
			case S_LINK :
				if (elementName.equals(NAME)) {
					state = S_LINK_PATH;
				} else if (elementName.equals(TYPE)) {
					state = S_LINK_TYPE;
				} else if (elementName.equals(LOCATION)) {
					state = S_LINK_LOCATION;
				} else if (elementName.equals(LOCATION_URI)) {
					state = S_LINK_LOCATION_URI;
				}
				break;
			case S_FILTERED_RESOURCES :
				if (elementName.equals(FILTER)) {
					state = S_FILTER;
					// Push place holders for the name, type, id and arguments of
					// this filter.
					objectStack.push(new FilterDescription());
				}
				break;
			case S_FILTER :
				if (elementName.equals(ID)) {
					state = S_FILTER_ID;
				} else if (elementName.equals(NAME)) {
					state = S_FILTER_PATH;
				} else if (elementName.equals(TYPE)) {
					state = S_FILTER_TYPE;
				} else if (elementName.equals(MATCHER)) {
					state = S_MATCHER;
					// Push an array for the matcher id and arguments
					objectStack.push(new Object[2]);
				}
				break;
			case S_MATCHER :
				if (elementName.equals(ID)) {
					state = S_MATCHER_ID;
				} else if (elementName.equals(ARGUMENTS)) {
					state = S_MATCHER_ARGUMENTS;
					objectStack.push(new ArrayList<FileInfoMatcherDescription>());
				}
				break;
			case S_MATCHER_ARGUMENTS :
				if (elementName.equals(MATCHER)) {
					state = S_MATCHER;
					// Push an array for the matcher id and arguments
					objectStack.push(new Object[2]);
				}
				break;
			case S_VARIABLE :
				if (elementName.equals(NAME)) {
					state = S_VARIABLE_NAME;
				} else if (elementName.equals(VALUE)) {
					state = S_VARIABLE_VALUE;
				}
				break;
		}
	}

	
See Also:
warning.warning(SAXParseException)/**
	 * @see ErrorHandler#warning(SAXParseException)
	 */
	@Override
	public void warning(SAXParseException error) {
		log(error);
	}
}