bundles/org.eclipse.equinox.common/src/org/eclipse/core/internal/boot/PlatformURLConnection.java - equinox/rt.equinox.bundles - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2015 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
  *     Sergey Prigogin (Google) - use parameterized types (bug 442021)
  *******************************************************************************/
 package org.eclipse.core.internal.boot;

 import java.io.*;
 import java.net.URL;
 import java.net.URLConnection;
 import java.util.Enumeration;
 import java.util.Properties;
 import org.eclipse.core.internal.runtime.Activator;
 import org.eclipse.core.internal.runtime.CommonMessages;
 import org.eclipse.osgi.service.debug.DebugOptions;
 import org.eclipse.osgi.util.NLS;
 import org.osgi.framework.Version;

 /**
  * Platform URL support
  */
 public abstract class PlatformURLConnection extends URLConnection {

 	// URL access
 	private boolean isInCache = false;
 	private boolean isJar = false;

 	//	protected URL url;				// declared in super (platform: URL)
 	private URL resolvedURL = null; // resolved file URL (e.g. http: URL)
 	private URL cachedURL = null; // file URL in cache (file: URL)

 	private URLConnection connection = null; // actual connection

 	// local cache
 	private static Properties cacheIndex = new Properties();
 	private static String cacheLocation;
 	private static String indexName;
 	private static String filePrefix;

 	// constants
 	private static final int BUF_SIZE = 32768;
 	private static final Object NOT_FOUND = new Object(); // marker
 	private static final String CACHE_PROP = ".cache.properties"; //$NON-NLS-1$
 	private static final String CACHE_LOCATION_PROP = "location"; //$NON-NLS-1$
 	private static final String CACHE_INDEX_PROP = "index"; //$NON-NLS-1$
 	private static final String CACHE_PREFIX_PROP = "prefix"; //$NON-NLS-1$
 	private static final String CACHE_INDEX = ".index.properties"; //$NON-NLS-1$
 	private static final String CACHE_DIR = ".eclipse-" + PlatformURLHandler.PROTOCOL + File.separator; //$NON-NLS-1$

 	// debug tracing
 	private static final String OPTION_DEBUG = "org.eclipse.core.runtime/url/debug"; //$NON-NLS-1$;
 	private static final String OPTION_DEBUG_CONNECT = OPTION_DEBUG + "/connect"; //$NON-NLS-1$;
 	private static final String OPTION_DEBUG_CACHE_LOOKUP = OPTION_DEBUG + "/cachelookup"; //$NON-NLS-1$;
 	private static final String OPTION_DEBUG_CACHE_COPY = OPTION_DEBUG + "/cachecopy"; //$NON-NLS-1$;

 	public final static boolean DEBUG;
 	public final static boolean DEBUG_CONNECT;
 	public final static boolean DEBUG_CACHE_LOOKUP;
 	public final static boolean DEBUG_CACHE_COPY;

 	static {
 		Activator activator = Activator.getDefault();
 		if (activator == null) {
 			DEBUG = DEBUG_CONNECT = DEBUG_CACHE_LOOKUP = DEBUG_CACHE_COPY = false;
 		} else {
 			DebugOptions debugOptions = activator.getDebugOptions();
 			if (debugOptions != null) {
 				DEBUG = debugOptions.getBooleanOption(OPTION_DEBUG, false);
 				DEBUG_CONNECT = debugOptions.getBooleanOption(OPTION_DEBUG_CONNECT, true);
 				DEBUG_CACHE_LOOKUP = debugOptions.getBooleanOption(OPTION_DEBUG_CACHE_LOOKUP, true);
 				DEBUG_CACHE_COPY = debugOptions.getBooleanOption(OPTION_DEBUG_CACHE_COPY, true);
 			} else
 				DEBUG = DEBUG_CONNECT = DEBUG_CACHE_LOOKUP = DEBUG_CACHE_COPY = false;
 		}
 	}

 	protected PlatformURLConnection(URL url) {
 		super(url);
 	}

 	protected boolean allowCaching() {
 		return false;
 	}

 	@Override
 	public void connect() throws IOException {
 		connect(false);
 	}

 	private synchronized void connect(boolean asLocal) throws IOException {
 		if (connected)
 			return;

 		if (shouldCache(asLocal)) {
 			try {
 				URL inCache = getURLInCache();
 				if (inCache != null)
 					connection = inCache.openConnection();
 			} catch (IOException e) {
 				// failed to cache ... will use resolved URL instead
 			}
 		}

 		// use resolved URL
 		if (connection == null)
 			connection = resolvedURL.openConnection();
 		connected = true;
 		if (DEBUG && DEBUG_CONNECT)
 			debug("Connected as " + connection.getURL()); //$NON-NLS-1$
 	}

 	//TODO consider refactoring this method... it is too long
 	//TODO avoid cryptic identifiers such as ix, tgt, tmp, srcis, tgtos...
 	private void copyToCache() throws IOException {

 		if (isInCache | cachedURL == null)
 			return;
 		String tmp;
 		int ix;

 		// cache entry key
 		String key;
 		if (isJar) {
 			tmp = url.getFile();
 			ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 			if (ix != -1)
 				tmp = tmp.substring(0, ix);
 			key = tmp;
 		} else
 			key = url.getFile();

 		// source url
 		URL src;
 		if (isJar) {
 			tmp = resolvedURL.getFile();
 			ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 			if (ix != -1)
 				tmp = tmp.substring(0, ix);
 			src = new URL(tmp);
 		} else
 			src = resolvedURL;
 		InputStream srcis = null;

 		// cache target
 		String tgt;
 		if (isJar) {
 			tmp = cachedURL.getFile();
 			ix = tmp.indexOf(PlatformURLHandler.PROTOCOL_SEPARATOR);
 			if (ix != -1)
 				tmp = tmp.substring(ix + 1);
 			ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 			if (ix != -1)
 				tmp = tmp.substring(0, ix);
 			tgt = tmp;
 		} else
 			tgt = cachedURL.getFile();
 		File tgtFile = null;
 		FileOutputStream tgtos = null;

 		boolean error = false;
 		long total = 0;

 		try {
 			if (DEBUG && DEBUG_CACHE_COPY) {
 				if (isJar)
 					debug("Caching jar as " + tgt); //$NON-NLS-1$
 				else
 					debug("Caching as " + tgt); //$NON-NLS-1$
 			}

 			srcis = src.openStream();
 			byte[] buf = new byte[BUF_SIZE];
 			int count = srcis.read(buf);

 			tgtFile = new File(tgt);
 			tgtos = new FileOutputStream(tgtFile);

 			while (count != -1) {
 				total += count;
 				tgtos.write(buf, 0, count);
 				count = srcis.read(buf);
 			}

 			srcis.close();
 			srcis = null;
 			tgtos.flush();
 			tgtos.getFD().sync();
 			tgtos.close();
 			tgtos = null;

 			// add cache entry
 			cacheIndex.put(key, tgt);
 			isInCache = true;
 		} catch (IOException e) {
 			error = true;
 			cacheIndex.put(key, NOT_FOUND);
 			// mark cache entry for this execution
 			if (DEBUG && DEBUG_CACHE_COPY)
 				debug("Failed to cache due to " + e); //$NON-NLS-1$
 			throw e;
 		} finally {
 			if (!error && DEBUG && DEBUG_CACHE_COPY)
 				debug(total + " bytes copied"); //$NON-NLS-1$
 			if (srcis != null)
 				srcis.close();
 			if (tgtos != null)
 				tgtos.close();
 		}
 	}

 	protected void debug(String s) {
 		System.out.println("URL " + getURL().toString() + "^" + Integer.toHexString(Thread.currentThread().hashCode()) + " " + s); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 	}

 	private static void debugStartup(String s) {
 		System.out.println("URL " + s); //$NON-NLS-1$
 	}

 	@Override
 	public synchronized InputStream getInputStream() throws IOException {
 		if (!connected)
 			connect();
 		return connection.getInputStream();
 	}

 	public URL getResolvedURL() {
 		return resolvedURL;
 	}

 	public URL getURLAsLocal() throws IOException {
 		connect(true); // connect and force caching if necessary
 		URL u = connection.getURL();
 		String up = u.getProtocol();
 		if (!up.equals(PlatformURLHandler.FILE) && !up.equals(PlatformURLHandler.JAR) && !up.startsWith(PlatformURLHandler.BUNDLE))
 			throw new IOException(NLS.bind(CommonMessages.url_noaccess, up));
 		return u;
 	}

 	//TODO consider refactoring this method... it is too long
 	private URL getURLInCache() throws IOException {

 		if (!allowCaching())
 			return null; // target should not be cached

 		if (isInCache)
 			return cachedURL;

 		if (cacheLocation == null | cacheIndex == null)
 			return null; // not caching

 		// check if we are dealing with a .jar/ .zip
 		String file = ""; //$NON-NLS-1$
 		String jarEntry = null;
 		if (isJar) {
 			file = url.getFile();
 			int ix = file.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 			if (ix != -1) {
 				jarEntry = file.substring(ix + PlatformURLHandler.JAR_SEPARATOR.length());
 				file = file.substring(0, ix);
 			}
 		} else {
 			file = url.getFile();
 		}

 		// check for cached entry
 		String tmp = (String) cacheIndex.get(file);

 		// check for "not found" marker
 		if (tmp != null && tmp == NOT_FOUND)
 			throw new IOException();

 		// validate cache entry
 		if (tmp != null && !(new File(tmp)).exists()) {
 			tmp = null;
 			cacheIndex.remove(url.getFile());
 		}

 		// found in cache
 		if (tmp != null) {
 			if (isJar) {
 				if (DEBUG && DEBUG_CACHE_LOOKUP)
 					debug("Jar located in cache as " + tmp); //$NON-NLS-1$
 				tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
 				cachedURL = new URL(PlatformURLHandler.JAR, null, -1, tmp);
 			} else {
 				if (DEBUG && DEBUG_CACHE_LOOKUP)
 					debug("Located in cache as " + tmp); //$NON-NLS-1$
 				cachedURL = new URL(PlatformURLHandler.FILE, null, -1, tmp);
 			}
 			isInCache = true;
 		} else {
 			// attempt to cache
 			int ix = file.lastIndexOf("/"); //$NON-NLS-1$
 			tmp = file.substring(ix + 1);
 			tmp = cacheLocation + filePrefix + Long.toString((new java.util.Date()).getTime()) + "_" + tmp; //$NON-NLS-1$
 			tmp = tmp.replace(File.separatorChar, '/');
 			if (isJar) {
 				tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
 				cachedURL = new URL(PlatformURLHandler.JAR, null, -1, tmp);
 			} else
 				cachedURL = new URL(PlatformURLHandler.FILE, null, -1, tmp);
 			copyToCache();
 		}

 		return cachedURL;
 	}

 	/*
 	 * to be implemented by subclass
 	 * @return URL resolved URL
 	 */
 	protected URL resolve() throws IOException {
 		// TODO throw UnsupportedOperationException instead - this is a bug in subclass, not an actual failure
 		throw new IOException();
 	}

 	protected static String getId(String spec) {
 		String id = (String) parse(spec)[0];
 		return id == null ? spec : id;
 	}

 	protected static String getVersion(String spec) {
 		Version version = (Version) parse(spec)[1];
 		return version == null ? "" : version.toString(); //$NON-NLS-1$
 	}

 	private static Object[] parse(String spec) {
 		String bsn = null;
 		Version version = null;
 		int underScore = spec.indexOf('_');
 		while (underScore >= 0) {
 			try {
 				version = Version.parseVersion(spec.substring(underScore + 1));
 			} catch (IllegalArgumentException iae) {
 				// continue to next underscore
 				underScore = spec.indexOf('_', underScore + 1);
 				continue;
 			}
 			bsn = spec.substring(0, underScore);
 			break;
 		}
 		return new Object[] {bsn, version};
 	}

 	void setResolvedURL(URL url) throws IOException {
 		if (url == null)
 			throw new IOException();
 		if (resolvedURL != null)
 			return;
 		int ix = url.getFile().lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
 		isJar = -1 != ix;
 		// Resolved URLs containing !/ separator are assumed to be jar URLs.
 		// If the resolved protocol is not jar, new jar URL is created.
 		if (isJar && !url.getProtocol().equals(PlatformURLHandler.JAR))
 			url = new URL(PlatformURLHandler.JAR, "", -1, url.toExternalForm()); //$NON-NLS-1$
 		resolvedURL = url;
 	}

 	private boolean shouldCache(boolean asLocal) {

 		// don't cache files that are known to be local
 		String rp = resolvedURL.getProtocol();
 		String rf = resolvedURL.getFile();
 		if (rp.equals(PlatformURLHandler.FILE))
 			return false;
 		if (rp.equals(PlatformURLHandler.JAR) && (rf.startsWith(PlatformURLHandler.FILE)))
 			return false;

 		// for other files force caching if local connection was requested
 		if (asLocal)
 			return true;

 		// for now cache all files
 		// XXX: add cache policy support
 		return true;
 	}

 	static void shutdown() {
 		if (indexName != null && cacheLocation != null) {
 			// weed out "not found" entries
 			Enumeration<Object> keys = cacheIndex.keys();
 			String key;
 			Object value;
 			while (keys.hasMoreElements()) {
 				key = (String) keys.nextElement();
 				value = cacheIndex.get(key);
 				if (value == NOT_FOUND)
 					cacheIndex.remove(key);
 			}
 			//if the cache index is empty we don't need to save it
 			if (cacheIndex.size() == 0)
 				return;
 			try {
 				// try to save cache index
 				FileOutputStream fos = null;
 				fos = new FileOutputStream(cacheLocation + indexName);
 				try {
 					cacheIndex.store(fos, null);
 					fos.flush();
 					fos.getFD().sync();
 				} finally {
 					fos.close();
 				}
 			} catch (IOException e) {
 				// failed to store cache index ... ignore
 			}
 		}
 	}

 	//TODO consider splitting this method into two or more steps - it is too long
 	static void startup(String location, String os, String ws, String nl) {
 		verifyLocation(location); // check for platform location, ignore errors
 		String cacheProps = location.trim();
 		if (!cacheProps.endsWith(File.separator))
 			cacheProps += File.separator;
 		cacheProps += CACHE_PROP;
 		File cachePropFile = new File(cacheProps);
 		Properties props = null;
 		FileInputStream fis;

 		if (cachePropFile.exists()) {
 			// load existing properties
 			try {
 				props = new Properties();
 				fis = new FileInputStream(cachePropFile);
 				try {
 					props.load(fis);
 				} finally {
 					fis.close();
 				}
 			} catch (IOException e) {
 				props = null;
 			}
 		}

 		if (props == null) {
 			// first time up, or failed to load previous settings
 			props = new Properties();

 			String tmp = System.getProperty("user.home"); //$NON-NLS-1$
 			if (!tmp.endsWith(File.separator))
 				tmp += File.separator;
 			tmp += CACHE_DIR;
 			props.put(CACHE_LOCATION_PROP, tmp);

 			tmp = Long.toString((new java.util.Date()).getTime());
 			props.put(CACHE_PREFIX_PROP, tmp);

 			tmp += CACHE_INDEX;
 			props.put(CACHE_INDEX_PROP, tmp);

 			// save for next time around
 			FileOutputStream fos = null;
 			try {
 				fos = new FileOutputStream(cachePropFile);
 				try {
 					props.store(fos, null);
 					fos.flush();
 					fos.getFD().sync();
 				} finally {
 					fos.close();
 				}
 			} catch (IOException e) {
 				// failed to store cache location metadata ... ignore
 			}
 		}

 		// remember settings for shutdown processing
 		filePrefix = (String) props.get(CACHE_PREFIX_PROP);
 		indexName = (String) props.get(CACHE_INDEX_PROP);
 		cacheLocation = (String) props.get(CACHE_LOCATION_PROP);

 		if (DEBUG) {
 			debugStartup("Cache location: " + cacheLocation); //$NON-NLS-1$
 			debugStartup("Cache index: " + indexName); //$NON-NLS-1$
 			debugStartup("Cache file prefix: " + filePrefix); //$NON-NLS-1$
 		}

 		// create cache directory structure if needed
 		if (!verifyLocation(cacheLocation)) {
 			indexName = null;
 			cacheLocation = null;
 			if (DEBUG)
 				debugStartup("Failed to create cache directory structure. Caching suspended"); //$NON-NLS-1$
 			return;
 		}

 		// attempt to initialize cache index
 		if (cacheLocation != null && indexName != null) {
 			try {
 				fis = new FileInputStream(cacheLocation + indexName);
 				try {
 					cacheIndex.load(fis);
 				} finally {
 					fis.close();
 				}
 			} catch (IOException e) {
 				if (DEBUG)
 					debugStartup("Failed to initialize cache"); //$NON-NLS-1$
 			}
 		}
 	}

 	private static boolean verifyLocation(String location) {
 		// verify cache directory exists. Create if needed
 		File cacheDir = new File(location);
 		if (cacheDir.exists())
 			return true;
 		return cacheDir.mkdirs();
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2015 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
	* Sergey Prigogin (Google) - use parameterized types (bug 442021)
	*******************************************************************************/
	package org.eclipse.core.internal.boot;

	import java.io.*;
	import java.net.URL;
	import java.net.URLConnection;
	import java.util.Enumeration;
	import java.util.Properties;
	import org.eclipse.core.internal.runtime.Activator;
	import org.eclipse.core.internal.runtime.CommonMessages;
	import org.eclipse.osgi.service.debug.DebugOptions;
	import org.eclipse.osgi.util.NLS;
	import org.osgi.framework.Version;

	/**
	* Platform URL support
	*/
	public abstract class PlatformURLConnection extends URLConnection {

	// URL access
	private boolean isInCache = false;
	private boolean isJar = false;

	// protected URL url; // declared in super (platform: URL)
	private URL resolvedURL = null; // resolved file URL (e.g. http: URL)
	private URL cachedURL = null; // file URL in cache (file: URL)

	private URLConnection connection = null; // actual connection

	// local cache
	private static Properties cacheIndex = new Properties();
	private static String cacheLocation;
	private static String indexName;
	private static String filePrefix;

	// constants
	private static final int BUF_SIZE = 32768;
	private static final Object NOT_FOUND = new Object(); // marker
	private static final String CACHE_PROP = ".cache.properties"; //$NON-NLS-1$
	private static final String CACHE_LOCATION_PROP = "location"; //$NON-NLS-1$
	private static final String CACHE_INDEX_PROP = "index"; //$NON-NLS-1$
	private static final String CACHE_PREFIX_PROP = "prefix"; //$NON-NLS-1$
	private static final String CACHE_INDEX = ".index.properties"; //$NON-NLS-1$
	private static final String CACHE_DIR = ".eclipse-" + PlatformURLHandler.PROTOCOL + File.separator; //$NON-NLS-1$

	// debug tracing
	private static final String OPTION_DEBUG = "org.eclipse.core.runtime/url/debug"; //$NON-NLS-1$;
	private static final String OPTION_DEBUG_CONNECT = OPTION_DEBUG + "/connect"; //$NON-NLS-1$;
	private static final String OPTION_DEBUG_CACHE_LOOKUP = OPTION_DEBUG + "/cachelookup"; //$NON-NLS-1$;
	private static final String OPTION_DEBUG_CACHE_COPY = OPTION_DEBUG + "/cachecopy"; //$NON-NLS-1$;

	public final static boolean DEBUG;
	public final static boolean DEBUG_CONNECT;
	public final static boolean DEBUG_CACHE_LOOKUP;
	public final static boolean DEBUG_CACHE_COPY;

	static {
	Activator activator = Activator.getDefault();
	if (activator == null) {
	DEBUG = DEBUG_CONNECT = DEBUG_CACHE_LOOKUP = DEBUG_CACHE_COPY = false;
	} else {
	DebugOptions debugOptions = activator.getDebugOptions();
	if (debugOptions != null) {
	DEBUG = debugOptions.getBooleanOption(OPTION_DEBUG, false);
	DEBUG_CONNECT = debugOptions.getBooleanOption(OPTION_DEBUG_CONNECT, true);
	DEBUG_CACHE_LOOKUP = debugOptions.getBooleanOption(OPTION_DEBUG_CACHE_LOOKUP, true);
	DEBUG_CACHE_COPY = debugOptions.getBooleanOption(OPTION_DEBUG_CACHE_COPY, true);
	} else
	DEBUG = DEBUG_CONNECT = DEBUG_CACHE_LOOKUP = DEBUG_CACHE_COPY = false;
	}
	}

	protected PlatformURLConnection(URL url) {
	super(url);
	}

	protected boolean allowCaching() {
	return false;
	}

	@Override
	public void connect() throws IOException {
	connect(false);
	}

	private synchronized void connect(boolean asLocal) throws IOException {
	if (connected)
	return;

	if (shouldCache(asLocal)) {
	try {
	URL inCache = getURLInCache();
	if (inCache != null)
	connection = inCache.openConnection();
	} catch (IOException e) {
	// failed to cache ... will use resolved URL instead
	}
	}

	// use resolved URL
	if (connection == null)
	connection = resolvedURL.openConnection();
	connected = true;
	if (DEBUG && DEBUG_CONNECT)
	debug("Connected as " + connection.getURL()); //$NON-NLS-1$
	}

	//TODO consider refactoring this method... it is too long
	//TODO avoid cryptic identifiers such as ix, tgt, tmp, srcis, tgtos...
	private void copyToCache() throws IOException {

	if (isInCache \| cachedURL == null)
	return;
	String tmp;
	int ix;

	// cache entry key
	String key;
	if (isJar) {
	tmp = url.getFile();
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix != -1)
	tmp = tmp.substring(0, ix);
	key = tmp;
	} else
	key = url.getFile();

	// source url
	URL src;
	if (isJar) {
	tmp = resolvedURL.getFile();
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix != -1)
	tmp = tmp.substring(0, ix);
	src = new URL(tmp);
	} else
	src = resolvedURL;
	InputStream srcis = null;

	// cache target
	String tgt;
	if (isJar) {
	tmp = cachedURL.getFile();
	ix = tmp.indexOf(PlatformURLHandler.PROTOCOL_SEPARATOR);
	if (ix != -1)
	tmp = tmp.substring(ix + 1);
	ix = tmp.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix != -1)
	tmp = tmp.substring(0, ix);
	tgt = tmp;
	} else
	tgt = cachedURL.getFile();
	File tgtFile = null;
	FileOutputStream tgtos = null;

	boolean error = false;
	long total = 0;

	try {
	if (DEBUG && DEBUG_CACHE_COPY) {
	if (isJar)
	debug("Caching jar as " + tgt); //$NON-NLS-1$
	else
	debug("Caching as " + tgt); //$NON-NLS-1$
	}

	srcis = src.openStream();
	byte[] buf = new byte[BUF_SIZE];
	int count = srcis.read(buf);

	tgtFile = new File(tgt);
	tgtos = new FileOutputStream(tgtFile);

	while (count != -1) {
	total += count;
	tgtos.write(buf, 0, count);
	count = srcis.read(buf);
	}

	srcis.close();
	srcis = null;
	tgtos.flush();
	tgtos.getFD().sync();
	tgtos.close();
	tgtos = null;

	// add cache entry
	cacheIndex.put(key, tgt);
	isInCache = true;
	} catch (IOException e) {
	error = true;
	cacheIndex.put(key, NOT_FOUND);
	// mark cache entry for this execution
	if (DEBUG && DEBUG_CACHE_COPY)
	debug("Failed to cache due to " + e); //$NON-NLS-1$
	throw e;
	} finally {
	if (!error && DEBUG && DEBUG_CACHE_COPY)
	debug(total + " bytes copied"); //$NON-NLS-1$
	if (srcis != null)
	srcis.close();
	if (tgtos != null)
	tgtos.close();
	}
	}

	protected void debug(String s) {
	System.out.println("URL " + getURL().toString() + "^" + Integer.toHexString(Thread.currentThread().hashCode()) + " " + s); //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
	}

	private static void debugStartup(String s) {
	System.out.println("URL " + s); //$NON-NLS-1$
	}

	@Override
	public synchronized InputStream getInputStream() throws IOException {
	if (!connected)
	connect();
	return connection.getInputStream();
	}

	public URL getResolvedURL() {
	return resolvedURL;
	}

	public URL getURLAsLocal() throws IOException {
	connect(true); // connect and force caching if necessary
	URL u = connection.getURL();
	String up = u.getProtocol();
	if (!up.equals(PlatformURLHandler.FILE) && !up.equals(PlatformURLHandler.JAR) && !up.startsWith(PlatformURLHandler.BUNDLE))
	throw new IOException(NLS.bind(CommonMessages.url_noaccess, up));
	return u;
	}

	//TODO consider refactoring this method... it is too long
	private URL getURLInCache() throws IOException {

	if (!allowCaching())
	return null; // target should not be cached

	if (isInCache)
	return cachedURL;

	if (cacheLocation == null \| cacheIndex == null)
	return null; // not caching

	// check if we are dealing with a .jar/ .zip
	String file = ""; //$NON-NLS-1$
	String jarEntry = null;
	if (isJar) {
	file = url.getFile();
	int ix = file.lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	if (ix != -1) {
	jarEntry = file.substring(ix + PlatformURLHandler.JAR_SEPARATOR.length());
	file = file.substring(0, ix);
	}
	} else {
	file = url.getFile();
	}

	// check for cached entry
	String tmp = (String) cacheIndex.get(file);

	// check for "not found" marker
	if (tmp != null && tmp == NOT_FOUND)
	throw new IOException();

	// validate cache entry
	if (tmp != null && !(new File(tmp)).exists()) {
	tmp = null;
	cacheIndex.remove(url.getFile());
	}

	// found in cache
	if (tmp != null) {
	if (isJar) {
	if (DEBUG && DEBUG_CACHE_LOOKUP)
	debug("Jar located in cache as " + tmp); //$NON-NLS-1$
	tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
	cachedURL = new URL(PlatformURLHandler.JAR, null, -1, tmp);
	} else {
	if (DEBUG && DEBUG_CACHE_LOOKUP)
	debug("Located in cache as " + tmp); //$NON-NLS-1$
	cachedURL = new URL(PlatformURLHandler.FILE, null, -1, tmp);
	}
	isInCache = true;
	} else {
	// attempt to cache
	int ix = file.lastIndexOf("/"); //$NON-NLS-1$
	tmp = file.substring(ix + 1);
	tmp = cacheLocation + filePrefix + Long.toString((new java.util.Date()).getTime()) + "_" + tmp; //$NON-NLS-1$
	tmp = tmp.replace(File.separatorChar, '/');
	if (isJar) {
	tmp = PlatformURLHandler.FILE + PlatformURLHandler.PROTOCOL_SEPARATOR + tmp + PlatformURLHandler.JAR_SEPARATOR + jarEntry;
	cachedURL = new URL(PlatformURLHandler.JAR, null, -1, tmp);
	} else
	cachedURL = new URL(PlatformURLHandler.FILE, null, -1, tmp);
	copyToCache();
	}

	return cachedURL;
	}

	/*
	* to be implemented by subclass
	* @return URL resolved URL
	*/
	protected URL resolve() throws IOException {
	// TODO throw UnsupportedOperationException instead - this is a bug in subclass, not an actual failure
	throw new IOException();
	}

	protected static String getId(String spec) {
	String id = (String) parse(spec)[0];
	return id == null ? spec : id;
	}

	protected static String getVersion(String spec) {
	Version version = (Version) parse(spec)[1];
	return version == null ? "" : version.toString(); //$NON-NLS-1$
	}

	private static Object[] parse(String spec) {
	String bsn = null;
	Version version = null;
	int underScore = spec.indexOf('_');
	while (underScore >= 0) {
	try {
	version = Version.parseVersion(spec.substring(underScore + 1));
	} catch (IllegalArgumentException iae) {
	// continue to next underscore
	underScore = spec.indexOf('_', underScore + 1);
	continue;
	}
	bsn = spec.substring(0, underScore);
	break;
	}
	return new Object[] {bsn, version};
	}

	void setResolvedURL(URL url) throws IOException {
	if (url == null)
	throw new IOException();
	if (resolvedURL != null)
	return;
	int ix = url.getFile().lastIndexOf(PlatformURLHandler.JAR_SEPARATOR);
	isJar = -1 != ix;
	// Resolved URLs containing !/ separator are assumed to be jar URLs.
	// If the resolved protocol is not jar, new jar URL is created.
	if (isJar && !url.getProtocol().equals(PlatformURLHandler.JAR))
	url = new URL(PlatformURLHandler.JAR, "", -1, url.toExternalForm()); //$NON-NLS-1$
	resolvedURL = url;
	}

	private boolean shouldCache(boolean asLocal) {

	// don't cache files that are known to be local
	String rp = resolvedURL.getProtocol();
	String rf = resolvedURL.getFile();
	if (rp.equals(PlatformURLHandler.FILE))
	return false;
	if (rp.equals(PlatformURLHandler.JAR) && (rf.startsWith(PlatformURLHandler.FILE)))
	return false;

	// for other files force caching if local connection was requested
	if (asLocal)
	return true;

	// for now cache all files
	// XXX: add cache policy support
	return true;
	}

	static void shutdown() {
	if (indexName != null && cacheLocation != null) {
	// weed out "not found" entries
	Enumeration<Object> keys = cacheIndex.keys();
	String key;
	Object value;
	while (keys.hasMoreElements()) {
	key = (String) keys.nextElement();
	value = cacheIndex.get(key);
	if (value == NOT_FOUND)
	cacheIndex.remove(key);
	}
	//if the cache index is empty we don't need to save it
	if (cacheIndex.size() == 0)
	return;
	try {
	// try to save cache index
	FileOutputStream fos = null;
	fos = new FileOutputStream(cacheLocation + indexName);
	try {
	cacheIndex.store(fos, null);
	fos.flush();
	fos.getFD().sync();
	} finally {
	fos.close();
	}
	} catch (IOException e) {
	// failed to store cache index ... ignore
	}
	}
	}

	//TODO consider splitting this method into two or more steps - it is too long
	static void startup(String location, String os, String ws, String nl) {
	verifyLocation(location); // check for platform location, ignore errors
	String cacheProps = location.trim();
	if (!cacheProps.endsWith(File.separator))
	cacheProps += File.separator;
	cacheProps += CACHE_PROP;
	File cachePropFile = new File(cacheProps);
	Properties props = null;
	FileInputStream fis;

	if (cachePropFile.exists()) {
	// load existing properties
	try {
	props = new Properties();
	fis = new FileInputStream(cachePropFile);
	try {
	props.load(fis);
	} finally {
	fis.close();
	}
	} catch (IOException e) {
	props = null;
	}
	}

	if (props == null) {
	// first time up, or failed to load previous settings
	props = new Properties();

	String tmp = System.getProperty("user.home"); //$NON-NLS-1$
	if (!tmp.endsWith(File.separator))
	tmp += File.separator;
	tmp += CACHE_DIR;
	props.put(CACHE_LOCATION_PROP, tmp);

	tmp = Long.toString((new java.util.Date()).getTime());
	props.put(CACHE_PREFIX_PROP, tmp);

	tmp += CACHE_INDEX;
	props.put(CACHE_INDEX_PROP, tmp);

	// save for next time around
	FileOutputStream fos = null;
	try {
	fos = new FileOutputStream(cachePropFile);
	try {
	props.store(fos, null);
	fos.flush();
	fos.getFD().sync();
	} finally {
	fos.close();
	}
	} catch (IOException e) {
	// failed to store cache location metadata ... ignore
	}
	}

	// remember settings for shutdown processing
	filePrefix = (String) props.get(CACHE_PREFIX_PROP);
	indexName = (String) props.get(CACHE_INDEX_PROP);
	cacheLocation = (String) props.get(CACHE_LOCATION_PROP);

	if (DEBUG) {
	debugStartup("Cache location: " + cacheLocation); //$NON-NLS-1$
	debugStartup("Cache index: " + indexName); //$NON-NLS-1$
	debugStartup("Cache file prefix: " + filePrefix); //$NON-NLS-1$
	}

	// create cache directory structure if needed
	if (!verifyLocation(cacheLocation)) {
	indexName = null;
	cacheLocation = null;
	if (DEBUG)
	debugStartup("Failed to create cache directory structure. Caching suspended"); //$NON-NLS-1$
	return;
	}

	// attempt to initialize cache index
	if (cacheLocation != null && indexName != null) {
	try {
	fis = new FileInputStream(cacheLocation + indexName);
	try {
	cacheIndex.load(fis);
	} finally {
	fis.close();
	}
	} catch (IOException e) {
	if (DEBUG)
	debugStartup("Failed to initialize cache"); //$NON-NLS-1$
	}
	}
	}

	private static boolean verifyLocation(String location) {
	// verify cache directory exists. Create if needed
	File cacheDir = new File(location);
	if (cacheDir.exists())
	return true;
	return cacheDir.mkdirs();
	}
	}