bundles/org.eclipse.equinox.p2.publisher/src/org/eclipse/equinox/internal/p2/publisher/features/UpdateSite.java - equinox/rt.equinox.p2 - Git at Google

 /*******************************************************************************
  * Copyright (c) 2008 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.equinox.internal.p2.publisher.features;

 import java.io.*;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.zip.*;
 import org.eclipse.core.runtime.*;
 import org.eclipse.equinox.internal.p2.core.helpers.FileUtils;
 import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
 import org.eclipse.equinox.internal.p2.publisher.Activator;
 import org.eclipse.equinox.internal.provisional.p2.core.ProvisionException;
 import org.eclipse.osgi.util.NLS;
 import org.xml.sax.SAXException;

 /**
  * @since 1.0
  */
 public class UpdateSite {

 	private static final String VERSION_SEPARATOR = "_"; //$NON-NLS-1$
 	private static final String JAR_EXTENSION = ".jar"; //$NON-NLS-1$
 	private static final String FEATURE_DIR = "features/"; //$NON-NLS-1$
 	private static final String PLUGIN_DIR = "plugins/"; //$NON-NLS-1$
 	private static final String FEATURE_TEMP_FILE = "feature"; //$NON-NLS-1$
 	private static final String SITE_FILE = "site.xml"; //$NON-NLS-1$
 	private static final String DIR_SEPARATOR = "/"; //$NON-NLS-1$
 	private String checksum;
 	private URL location;
 	private SiteModel site;

 	/*
 	 * Some variables for caching.
 	 */
 	// map of String (URL.toExternalForm()) to UpdateSite
 	private static Map siteCache = new HashMap();
 	// map of String (featureID_featureVersion) to Feature
 	private Map featureCache = new HashMap();

 	/*
 	 * Return a new URL for the given file which is based from the specified root.
 	 */
 	public static URL getFileURL(URL root, String fileName) throws MalformedURLException {
 		if (root.getPath().endsWith(fileName))
 			return root;
 		if (root.getPath().endsWith(SITE_FILE))
 			return new URL(root, fileName);
 		if (root.getPath().endsWith(DIR_SEPARATOR))
 			return new URL(root.toExternalForm() + fileName);
 		return new URL(root.toExternalForm() + DIR_SEPARATOR + fileName);
 	}

 	/*
 	 * Open and return the input stream for the given URL.
 	 */
 	private static InputStream getSiteInputStream(URL url) throws ProvisionException {
 		try {
 			return getSiteURL(url).openStream();
 		} catch (MalformedURLException e) {
 			String msg = NLS.bind(Messages.InvalidRepositoryLocation, url);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
 		} catch (IllegalArgumentException e) {
 			//see bug 221600 - URL.openStream can throw IllegalArgumentException
 			String msg = NLS.bind(Messages.InvalidRepositoryLocation, url);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
 		} catch (IOException e) {
 			String msg = NLS.bind(Messages.ErrorReadingSite, url);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_NOT_FOUND, msg, e));
 		}
 	}

 	/*
 	 * Return a URL based on the given URL, which points to a site.xml file.
 	 */
 	private static URL getSiteURL(URL url) throws MalformedURLException {
 		if (url.getPath().endsWith(SITE_FILE))
 			return url;
 		if (url.getPath().endsWith(DIR_SEPARATOR))
 			return new URL(url.toExternalForm() + SITE_FILE);
 		return new URL(url.toExternalForm() + DIR_SEPARATOR + SITE_FILE);
 	}

 	/*
 	 * Load and return an update site object from the given location.
 	 */
 	public static UpdateSite load(URL location, IProgressMonitor monitor) throws ProvisionException {
 		if (location == null)
 			return null;
 		UpdateSite result = (UpdateSite) siteCache.get(location.toExternalForm());
 		if (result != null)
 			return result;
 		InputStream input = getSiteInputStream(location);
 		try {
 			DefaultSiteParser siteParser = new DefaultSiteParser();
 			Checksum checksum = new CRC32();
 			input = new CheckedInputStream(new BufferedInputStream(input), checksum);
 			SiteModel siteModel = siteParser.parse(input);
 			String checksumString = Long.toString(checksum.getValue());
 			result = new UpdateSite(siteModel, location, checksumString);
 			siteCache.put(location.toExternalForm(), result);
 			return result;
 		} catch (SAXException e) {
 			String msg = NLS.bind(Messages.ErrorReadingSite, location);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, e));
 		} catch (IOException e) {
 			String msg = NLS.bind(Messages.ErrorReadingSite, location);
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, e));
 		} finally {
 			try {
 				input.close();
 			} catch (IOException e) {
 				// ignore
 			}
 		}
 	}

 	/*
 	 * Parse the feature.xml specified by the given input stream and return the feature object.
 	 */
 	private static Feature parseFeature(FeatureParser featureParser, URL featureURL) throws IOException, FileNotFoundException, ProvisionException {
 		File featureFile = File.createTempFile(FEATURE_TEMP_FILE, JAR_EXTENSION);
 		try {
 			FileUtils.copyStream(featureURL.openStream(), true, new BufferedOutputStream(new FileOutputStream(featureFile)), true);
 			return featureParser.parse(featureFile);
 		} catch (IllegalArgumentException e) {
 			//see bug 221600 - URL.openStream can throw IllegalArgumentException
 			String msg = NLS.bind(Messages.InvalidRepositoryLocation, featureURL.toExternalForm());
 			throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
 		} finally {
 			featureFile.delete();
 		}
 	}

 	/*
 	 * Throw an exception if the site pointed to by the given URL is not valid.
 	 */
 	public static void validate(URL url, IProgressMonitor monitor) throws ProvisionException {
 		InputStream input = getSiteInputStream(url);
 		try {
 			input.close();
 		} catch (IOException e) {
 			// ignore
 		}
 	}

 	/*
 	 * Constructor for the class.
 	 */
 	private UpdateSite(SiteModel site, URL location, String checksum) {
 		super();
 		this.site = site;
 		this.location = location;
 		this.checksum = checksum;
 	}

 	/*
 	 * Iterate over the archive entries in this site and return the matching URL string for
 	 * the given identifier, if there is one.
 	 */
 	private URL getArchiveURL(URL base, String identifier) {
 		URLEntry[] archives = site.getArchives();
 		for (int i = 0; archives != null && i < archives.length; i++) {
 			URLEntry entry = archives[i];
 			if (identifier.equals(entry.getAnnotation()))
 				return internalGetURL(base, entry.getURL());
 		}
 		return null;
 	}

 	/*
 	 * Return the checksum for this site.
 	 */
 	public String getChecksum() {
 		return checksum;
 	}

 	/*
 	 * Return a URL which represents the location of the given feature.
 	 */
 	public URL getFeatureURL(SiteFeature siteFeature, String id, String version) {
 		URL base = site.getLocationURL();
 		if (base == null)
 			base = location;
 		if (siteFeature == null) {
 			SiteFeature[] entries = site.getFeatures();
 			for (int i = 0; i < entries.length; i++) {
 				if (id.equals(entries[i].getFeatureIdentifier()) && version.equals(entries[i].getFeatureVersion())) {
 					siteFeature = entries[i];
 					break;
 				}
 			}
 		}
 		if (siteFeature != null) {
 			URL url = siteFeature.getURL();
 			if (url != null)
 				return url;
 			url = getArchiveURL(base, id);
 			if (url != null)
 				return url;
 		}
 		// fall through to default URL
 		try {
 			return getFileURL(base, FEATURE_DIR + id + VERSION_SEPARATOR + version + JAR_EXTENSION);
 		} catch (MalformedURLException e) {
 			// shouldn't happen
 		}
 		return null;
 	}

 	/*
 	 * Return the location of this site.
 	 */
 	public URL getLocation() {
 		return location;
 	}

 	/*
 	 * Return a URL which represents the location of the given plug-in.
 	 */
 	public URL getPluginURL(FeatureEntry plugin) {
 		URL base = site.getLocationURL();
 		if (base == null)
 			base = location;
 		String path = PLUGIN_DIR + plugin.getId() + VERSION_SEPARATOR + plugin.getVersion() + JAR_EXTENSION;
 		URL url = getArchiveURL(base, path);
 		if (url != null)
 			return url;
 		try {
 			return getFileURL(base, path);
 		} catch (MalformedURLException e) {
 			// shouldn't happen
 		}
 		return null;
 	}

 	/*
 	 * Return the site model.
 	 */
 	public SiteModel getSite() {
 		return site;
 	}

 	/*
 	 * The trailing parameter can be either null, relative or absolute. If it is null,
 	 * then return null. If it is absolute, then create a new url and return it. If it is
 	 * relative, then make it relative to the given base url.
 	 */
 	private URL internalGetURL(URL base, String trailing) {
 		if (trailing == null)
 			return null;
 		try {
 			return new URL(trailing);
 		} catch (MalformedURLException e) {
 			try {
 				return new URL(base, trailing);
 			} catch (MalformedURLException e2) {
 				// shouldn't happen
 			}
 		}
 		return null;
 	}

 	/*
 	 * Load and return the features references in this update site.
 	 */
 	public Feature[] loadFeatures() throws ProvisionException {
 		Feature[] result = loadFeaturesFromDigest();
 		return result == null ? loadFeaturesFromSite() : result;
 	}

 	/*
 	 * Try and load the feature information from the update site's
 	 * digest file, if it exists.
 	 */
 	private Feature[] loadFeaturesFromDigest() throws ProvisionException {
 		if (!featureCache.isEmpty())
 			return (Feature[]) featureCache.values().toArray(new Feature[featureCache.size()]);
 		try {
 			URL digestURL = getFileURL(location, "digest.zip"); //$NON-NLS-1$
 			File digestFile = File.createTempFile("digest", ".zip"); //$NON-NLS-1$ //$NON-NLS-2$
 			try {
 				FileUtils.copyStream(digestURL.openStream(), true, new BufferedOutputStream(new FileOutputStream(digestFile)), true);
 				Feature[] result = new DigestParser().parse(digestFile);
 				if (result == null)
 					return null;
 				for (int i = 0; i < result.length; i++) {
 					String key = result[i].getId() + VERSION_SEPARATOR + result[i].getVersion();
 					featureCache.put(key, result[i]);
 				}
 				return result;
 			} catch (IllegalArgumentException e) {
 				//see bug 221600 - URL.openStream can throw IllegalArgumentException
 				String msg = NLS.bind(Messages.InvalidRepositoryLocation, digestURL.toExternalForm());
 				throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
 			} finally {
 				digestFile.delete();
 			}
 		} catch (MalformedURLException e) {
 			LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingDigest, location), e));
 		} catch (IOException e) {
 			LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingDigest, location), e));
 		}
 		return null;
 	}

 	/*
 	 * Load and return the features that are referenced by this update site. Note this
 	 * requires downloading and parsing the feature manifest locally.
 	 */
 	private Feature[] loadFeaturesFromSite() throws ProvisionException {
 		SiteFeature[] siteFeatures = site.getFeatures();
 		FeatureParser featureParser = new FeatureParser();
 		for (int i = 0; i < siteFeatures.length; i++) {
 			SiteFeature siteFeature = siteFeatures[i];
 			String key = siteFeature.getFeatureIdentifier() + VERSION_SEPARATOR + siteFeature.getFeatureVersion();
 			if (featureCache.containsKey(key))
 				continue;
 			URL featureURL = getFeatureURL(siteFeature, siteFeature.getFeatureIdentifier(), siteFeature.getFeatureVersion());
 			try {
 				Feature feature = parseFeature(featureParser, featureURL);
 				if (feature == null) {
 					LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL)));
 				} else {
 					featureCache.put(key, feature);
 					loadIncludedFeatures(feature, featureParser);
 				}
 			} catch (IOException e) {
 				LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL), e));
 			}
 		}
 		return (Feature[]) featureCache.values().toArray(new Feature[featureCache.size()]);
 	}

 	/*
 	 * Load the features that are included by the given feature.
 	 */
 	private void loadIncludedFeatures(Feature feature, FeatureParser featureParser) throws ProvisionException {
 		FeatureEntry[] featureEntries = feature.getEntries();
 		for (int i = 0; i < featureEntries.length; i++) {
 			FeatureEntry entry = featureEntries[i];
 			if (entry.isRequires() || entry.isPlugin())
 				continue;
 			String key = entry.getId() + VERSION_SEPARATOR + entry.getVersion();
 			if (featureCache.containsKey(key))
 				continue;
 			URL featureURL = null;
 			try {
 				featureURL = getFileURL(location, FEATURE_DIR + entry.getId() + VERSION_SEPARATOR + entry.getVersion() + JAR_EXTENSION);
 				Feature includedFeature = parseFeature(featureParser, featureURL);
 				if (feature == null) {
 					LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL)));
 				} else {
 					featureCache.put(key, includedFeature);
 					loadIncludedFeatures(includedFeature, featureParser);
 				}
 			} catch (MalformedURLException e) {
 				LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, entry.getId()), e));
 			} catch (IOException e) {
 				LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL), e));
 			}
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2008 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.equinox.internal.p2.publisher.features;

	import java.io.*;
	import java.net.MalformedURLException;
	import java.net.URL;
	import java.util.HashMap;
	import java.util.Map;
	import java.util.zip.*;
	import org.eclipse.core.runtime.*;
	import org.eclipse.equinox.internal.p2.core.helpers.FileUtils;
	import org.eclipse.equinox.internal.p2.core.helpers.LogHelper;
	import org.eclipse.equinox.internal.p2.publisher.Activator;
	import org.eclipse.equinox.internal.provisional.p2.core.ProvisionException;
	import org.eclipse.osgi.util.NLS;
	import org.xml.sax.SAXException;

	/**
	* @since 1.0
	*/
	public class UpdateSite {

	private static final String VERSION_SEPARATOR = "_"; //$NON-NLS-1$
	private static final String JAR_EXTENSION = ".jar"; //$NON-NLS-1$
	private static final String FEATURE_DIR = "features/"; //$NON-NLS-1$
	private static final String PLUGIN_DIR = "plugins/"; //$NON-NLS-1$
	private static final String FEATURE_TEMP_FILE = "feature"; //$NON-NLS-1$
	private static final String SITE_FILE = "site.xml"; //$NON-NLS-1$
	private static final String DIR_SEPARATOR = "/"; //$NON-NLS-1$
	private String checksum;
	private URL location;
	private SiteModel site;

	/*
	* Some variables for caching.
	*/
	// map of String (URL.toExternalForm()) to UpdateSite
	private static Map siteCache = new HashMap();
	// map of String (featureID_featureVersion) to Feature
	private Map featureCache = new HashMap();

	/*
	* Return a new URL for the given file which is based from the specified root.
	*/
	public static URL getFileURL(URL root, String fileName) throws MalformedURLException {
	if (root.getPath().endsWith(fileName))
	return root;
	if (root.getPath().endsWith(SITE_FILE))
	return new URL(root, fileName);
	if (root.getPath().endsWith(DIR_SEPARATOR))
	return new URL(root.toExternalForm() + fileName);
	return new URL(root.toExternalForm() + DIR_SEPARATOR + fileName);
	}

	/*
	* Open and return the input stream for the given URL.
	*/
	private static InputStream getSiteInputStream(URL url) throws ProvisionException {
	try {
	return getSiteURL(url).openStream();
	} catch (MalformedURLException e) {
	String msg = NLS.bind(Messages.InvalidRepositoryLocation, url);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
	} catch (IllegalArgumentException e) {
	//see bug 221600 - URL.openStream can throw IllegalArgumentException
	String msg = NLS.bind(Messages.InvalidRepositoryLocation, url);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
	} catch (IOException e) {
	String msg = NLS.bind(Messages.ErrorReadingSite, url);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_NOT_FOUND, msg, e));
	}
	}

	/*
	* Return a URL based on the given URL, which points to a site.xml file.
	*/
	private static URL getSiteURL(URL url) throws MalformedURLException {
	if (url.getPath().endsWith(SITE_FILE))
	return url;
	if (url.getPath().endsWith(DIR_SEPARATOR))
	return new URL(url.toExternalForm() + SITE_FILE);
	return new URL(url.toExternalForm() + DIR_SEPARATOR + SITE_FILE);
	}

	/*
	* Load and return an update site object from the given location.
	*/
	public static UpdateSite load(URL location, IProgressMonitor monitor) throws ProvisionException {
	if (location == null)
	return null;
	UpdateSite result = (UpdateSite) siteCache.get(location.toExternalForm());
	if (result != null)
	return result;
	InputStream input = getSiteInputStream(location);
	try {
	DefaultSiteParser siteParser = new DefaultSiteParser();
	Checksum checksum = new CRC32();
	input = new CheckedInputStream(new BufferedInputStream(input), checksum);
	SiteModel siteModel = siteParser.parse(input);
	String checksumString = Long.toString(checksum.getValue());
	result = new UpdateSite(siteModel, location, checksumString);
	siteCache.put(location.toExternalForm(), result);
	return result;
	} catch (SAXException e) {
	String msg = NLS.bind(Messages.ErrorReadingSite, location);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, e));
	} catch (IOException e) {
	String msg = NLS.bind(Messages.ErrorReadingSite, location);
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_FAILED_READ, msg, e));
	} finally {
	try {
	input.close();
	} catch (IOException e) {
	// ignore
	}
	}
	}

	/*
	* Parse the feature.xml specified by the given input stream and return the feature object.
	*/
	private static Feature parseFeature(FeatureParser featureParser, URL featureURL) throws IOException, FileNotFoundException, ProvisionException {
	File featureFile = File.createTempFile(FEATURE_TEMP_FILE, JAR_EXTENSION);
	try {
	FileUtils.copyStream(featureURL.openStream(), true, new BufferedOutputStream(new FileOutputStream(featureFile)), true);
	return featureParser.parse(featureFile);
	} catch (IllegalArgumentException e) {
	//see bug 221600 - URL.openStream can throw IllegalArgumentException
	String msg = NLS.bind(Messages.InvalidRepositoryLocation, featureURL.toExternalForm());
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
	} finally {
	featureFile.delete();
	}
	}

	/*
	* Throw an exception if the site pointed to by the given URL is not valid.
	*/
	public static void validate(URL url, IProgressMonitor monitor) throws ProvisionException {
	InputStream input = getSiteInputStream(url);
	try {
	input.close();
	} catch (IOException e) {
	// ignore
	}
	}

	/*
	* Constructor for the class.
	*/
	private UpdateSite(SiteModel site, URL location, String checksum) {
	super();
	this.site = site;
	this.location = location;
	this.checksum = checksum;
	}

	/*
	* Iterate over the archive entries in this site and return the matching URL string for
	* the given identifier, if there is one.
	*/
	private URL getArchiveURL(URL base, String identifier) {
	URLEntry[] archives = site.getArchives();
	for (int i = 0; archives != null && i < archives.length; i++) {
	URLEntry entry = archives[i];
	if (identifier.equals(entry.getAnnotation()))
	return internalGetURL(base, entry.getURL());
	}
	return null;
	}

	/*
	* Return the checksum for this site.
	*/
	public String getChecksum() {
	return checksum;
	}

	/*
	* Return a URL which represents the location of the given feature.
	*/
	public URL getFeatureURL(SiteFeature siteFeature, String id, String version) {
	URL base = site.getLocationURL();
	if (base == null)
	base = location;
	if (siteFeature == null) {
	SiteFeature[] entries = site.getFeatures();
	for (int i = 0; i < entries.length; i++) {
	if (id.equals(entries[i].getFeatureIdentifier()) && version.equals(entries[i].getFeatureVersion())) {
	siteFeature = entries[i];
	break;
	}
	}
	}
	if (siteFeature != null) {
	URL url = siteFeature.getURL();
	if (url != null)
	return url;
	url = getArchiveURL(base, id);
	if (url != null)
	return url;
	}
	// fall through to default URL
	try {
	return getFileURL(base, FEATURE_DIR + id + VERSION_SEPARATOR + version + JAR_EXTENSION);
	} catch (MalformedURLException e) {
	// shouldn't happen
	}
	return null;
	}

	/*
	* Return the location of this site.
	*/
	public URL getLocation() {
	return location;
	}

	/*
	* Return a URL which represents the location of the given plug-in.
	*/
	public URL getPluginURL(FeatureEntry plugin) {
	URL base = site.getLocationURL();
	if (base == null)
	base = location;
	String path = PLUGIN_DIR + plugin.getId() + VERSION_SEPARATOR + plugin.getVersion() + JAR_EXTENSION;
	URL url = getArchiveURL(base, path);
	if (url != null)
	return url;
	try {
	return getFileURL(base, path);
	} catch (MalformedURLException e) {
	// shouldn't happen
	}
	return null;
	}

	/*
	* Return the site model.
	*/
	public SiteModel getSite() {
	return site;
	}

	/*
	* The trailing parameter can be either null, relative or absolute. If it is null,
	* then return null. If it is absolute, then create a new url and return it. If it is
	* relative, then make it relative to the given base url.
	*/
	private URL internalGetURL(URL base, String trailing) {
	if (trailing == null)
	return null;
	try {
	return new URL(trailing);
	} catch (MalformedURLException e) {
	try {
	return new URL(base, trailing);
	} catch (MalformedURLException e2) {
	// shouldn't happen
	}
	}
	return null;
	}

	/*
	* Load and return the features references in this update site.
	*/
	public Feature[] loadFeatures() throws ProvisionException {
	Feature[] result = loadFeaturesFromDigest();
	return result == null ? loadFeaturesFromSite() : result;
	}

	/*
	* Try and load the feature information from the update site's
	* digest file, if it exists.
	*/
	private Feature[] loadFeaturesFromDigest() throws ProvisionException {
	if (!featureCache.isEmpty())
	return (Feature[]) featureCache.values().toArray(new Feature[featureCache.size()]);
	try {
	URL digestURL = getFileURL(location, "digest.zip"); //$NON-NLS-1$
	File digestFile = File.createTempFile("digest", ".zip"); //$NON-NLS-1$ //$NON-NLS-2$
	try {
	FileUtils.copyStream(digestURL.openStream(), true, new BufferedOutputStream(new FileOutputStream(digestFile)), true);
	Feature[] result = new DigestParser().parse(digestFile);
	if (result == null)
	return null;
	for (int i = 0; i < result.length; i++) {
	String key = result[i].getId() + VERSION_SEPARATOR + result[i].getVersion();
	featureCache.put(key, result[i]);
	}
	return result;
	} catch (IllegalArgumentException e) {
	//see bug 221600 - URL.openStream can throw IllegalArgumentException
	String msg = NLS.bind(Messages.InvalidRepositoryLocation, digestURL.toExternalForm());
	throw new ProvisionException(new Status(IStatus.ERROR, Activator.ID, ProvisionException.REPOSITORY_INVALID_LOCATION, msg, e));
	} finally {
	digestFile.delete();
	}
	} catch (MalformedURLException e) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingDigest, location), e));
	} catch (IOException e) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingDigest, location), e));
	}
	return null;
	}

	/*
	* Load and return the features that are referenced by this update site. Note this
	* requires downloading and parsing the feature manifest locally.
	*/
	private Feature[] loadFeaturesFromSite() throws ProvisionException {
	SiteFeature[] siteFeatures = site.getFeatures();
	FeatureParser featureParser = new FeatureParser();
	for (int i = 0; i < siteFeatures.length; i++) {
	SiteFeature siteFeature = siteFeatures[i];
	String key = siteFeature.getFeatureIdentifier() + VERSION_SEPARATOR + siteFeature.getFeatureVersion();
	if (featureCache.containsKey(key))
	continue;
	URL featureURL = getFeatureURL(siteFeature, siteFeature.getFeatureIdentifier(), siteFeature.getFeatureVersion());
	try {
	Feature feature = parseFeature(featureParser, featureURL);
	if (feature == null) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL)));
	} else {
	featureCache.put(key, feature);
	loadIncludedFeatures(feature, featureParser);
	}
	} catch (IOException e) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL), e));
	}
	}
	return (Feature[]) featureCache.values().toArray(new Feature[featureCache.size()]);
	}

	/*
	* Load the features that are included by the given feature.
	*/
	private void loadIncludedFeatures(Feature feature, FeatureParser featureParser) throws ProvisionException {
	FeatureEntry[] featureEntries = feature.getEntries();
	for (int i = 0; i < featureEntries.length; i++) {
	FeatureEntry entry = featureEntries[i];
	if (entry.isRequires() \|\| entry.isPlugin())
	continue;
	String key = entry.getId() + VERSION_SEPARATOR + entry.getVersion();
	if (featureCache.containsKey(key))
	continue;
	URL featureURL = null;
	try {
	featureURL = getFileURL(location, FEATURE_DIR + entry.getId() + VERSION_SEPARATOR + entry.getVersion() + JAR_EXTENSION);
	Feature includedFeature = parseFeature(featureParser, featureURL);
	if (feature == null) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL)));
	} else {
	featureCache.put(key, includedFeature);
	loadIncludedFeatures(includedFeature, featureParser);
	}
	} catch (MalformedURLException e) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, entry.getId()), e));
	} catch (IOException e) {
	LogHelper.log(new Status(IStatus.ERROR, Activator.ID, NLS.bind(Messages.ErrorReadingFeature, featureURL), e));
	}
	}
	}
	}