bundles/org.eclipse.core.runtime/src/org/eclipse/core/internal/registry/RegistryCacheReader.java - gerrit/platform/eclipse.platform.runtime - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.core.internal.registry;

 import java.io.*;
 import java.util.ArrayList;
 import java.util.List;
 import org.eclipse.core.internal.runtime.InternalPlatform;
 import org.eclipse.core.internal.runtime.Policy;
 import org.eclipse.core.runtime.*;

 /**
  * Failure reporting strategy:
  * - when reading an identified element (bundles, extension points and extensions),
  * catch any IOExceptions and rethrow them wrapped into a InvalidRegistryCacheException
  * that describes where the error happened
  * - IOExceptions while reading non-identified elements (configuration elements and properties)
  * are just propagated to their callers
  * - the public entry points will catch any exceptions to ensure they are logged and return a valid
  * value instead (for instance, a null reference or an empty array)
  */
 public class RegistryCacheReader {

 	MultiStatus problems = null;
 	// objectTable will be an array list of objects. The objects will be things
 	// like a plugin descriptor, extension point, etc. The integer
 	// index value will be used in the cache to allow cross-references in the
 	// cached registry.
 	protected List objectTable = null;
 	private boolean lazilyLoadExtensions;
 	private boolean flushableExtensions = true;
 	// indicates we failed load configuration elements lazily
 	private boolean failed;
 	protected File cacheFile;

 	public static final byte REGISTRY_CACHE_VERSION = 7;
 	public static final byte NULL = 0;
 	public static final byte OBJECT = 1;
 	public static final byte INDEX = 2;

 	public RegistryCacheReader(File cacheFile, MultiStatus problems, boolean lazilyLoadExtensions, boolean flushable) {
 		super();
 		this.cacheFile = cacheFile;
 		this.problems = problems;
 		this.lazilyLoadExtensions = lazilyLoadExtensions;
 		this.flushableExtensions = flushable;
 		objectTable = new ArrayList();
 	}

 	public RegistryCacheReader(File cacheFile, MultiStatus problems) {
 		this(cacheFile, problems, false, true);
 	}

 	private int addToObjectTable(Object object) {
 		objectTable.add(object);
 		// return the index of the object just added (i.e. size - 1)
 		return (objectTable.size() - 1);
 	}

 	private void debug(String msg) {
 		System.out.println("RegistryCacheReader: " + msg); //$NON-NLS-1$
 	}

 	private boolean readHeaderInformation(DataInputStream in, long expectedTimestamp) throws InvalidRegistryCacheException {
 		try {
 			if (in.readInt() != REGISTRY_CACHE_VERSION)
 				return false;
 			long installStamp = in.readLong();
 			long registryStamp = in.readLong();
 			String osStamp = in.readUTF();
 			String windowsStamp = in.readUTF();
 			String localeStamp = in.readUTF();
 			InternalPlatform info = InternalPlatform.getDefault();
 			return ((expectedTimestamp == 0 || expectedTimestamp == registryStamp) && (installStamp == info.getStateTimeStamp()) && (osStamp.equals(info.getOS())) && (windowsStamp.equals(info.getWS())) && (localeStamp.equals(info.getNL())));
 		} catch (IOException e) {
 			throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "HeaderInformation"), e); //$NON-NLS-1$//$NON-NLS-2$
 		}
 	}

 	private void skipConfigurationElement(RegistryModelObject parent, DataInputStream in) throws IOException {
 		readCachedString(in, false); //read name
 		skipString(in); //skip value

 		int length = in.readInt();
 		for (int i = 0; i < length; i++) {
 			skipConfigurationProperty(in);
 		}
 		length = in.readInt();
 		for (int i = 0; i < length; i++) {
 			skipConfigurationElement(null, in);
 		}
 	}

 	private ConfigurationElement readConfigurationElement(RegistryModelObject parent, DataInputStream in) throws IOException {
 		ConfigurationElement result = new ConfigurationElement();
 		result.setParent(parent);
 		result.setName(readCachedString(in, false));
 		result.setValue(readString(in, false));

 		int length = in.readInt();
 		ConfigurationProperty[] properties = new ConfigurationProperty[length];
 		for (int i = 0; i < length; i++) {
 			properties[i] = readConfigurationProperty(in);
 		}
 		result.setProperties(properties);

 		length = in.readInt();
 		IConfigurationElement[] elements = new ConfigurationElement[length];
 		for (int i = 0; i < length; i++) {
 			elements[i] = readConfigurationElement(result, in);
 		}
 		result.setChildren(elements);
 		return result;
 	}

 	private void skipConfigurationProperty(DataInputStream in) throws IOException {
 		readCachedString(in, false); //Read the name
 		skipString(in); // skip the value
 	}

 	private ConfigurationProperty readConfigurationProperty(DataInputStream in) throws IOException {
 		String name = readCachedString(in, false);
 		ConfigurationProperty result = new ConfigurationProperty();
 		result.setName(name);
 		result.setValue(readString(in, false));
 		return result;
 	}

 	private Extension readExtension(DataInputStream in) throws InvalidRegistryCacheException {
 		Extension result = null;
 		try {
 			result = (Extension) readIndex(in);
 			if (result != null)
 				return result;
 			result = flushableExtensions ? new FlushableExtension() : new Extension();
 			addToObjectTable(result);
 			result.setSimpleIdentifier(readString(in, false));
 			result.setParent(readBundleModel(in));
 			result.setName(readString(in, false));
 			result.setExtensionPointIdentifier(readCachedString(in, false));
 			result.setSubElements(readSubElements(result, in));
 			return result;
 		} catch (IOException e) {
 			String extensionId = null;
 			if (result != null && result.getParent() != null)
 				extensionId = result.getParentIdentifier() + "." + result.getSimpleIdentifier(); //$NON-NLS-1$
 			throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "extension:  " + extensionId), e); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}

 	private ExtensionPoint readExtensionPoint(Namespace bundle, DataInputStream in) throws InvalidRegistryCacheException {
 		ExtensionPoint result = null;
 		try {
 			result = (ExtensionPoint) readIndex(in);
 			if (result != null)
 				return result;
 			result = new ExtensionPoint();
 			addToObjectTable(result);
 			result.setParent(bundle);
 			result.setSimpleIdentifier(readString(in, true));
 			result.setName(readString(in, false));
 			result.setSchema(readString(in, false));

 			// Now do the extensions.
 			int length = in.readInt();
 			IExtension[] extensions = new Extension[length];
 			for (int i = 0; i < length; i++)
 				extensions[i] = readExtension(in);
 			result.setExtensions(extensions);
 			return result;
 		} catch (IOException e) {
 			String extensionPointId = null;
 			if (result != null && result.getParent() != null)
 				extensionPointId = result.getUniqueIdentifier();
 			throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "extension point: " + extensionPointId), e); //$NON-NLS-1$ //$NON-NLS-2$
 		}
 	}

 	private Namespace readBundleModel(DataInputStream in) throws InvalidRegistryCacheException {
 		Namespace result = null;
 		try {
 			result = (Namespace) readIndex(in);
 			if (result != null)
 				return result;
 			result = new Namespace();
 			addToObjectTable(result);
 			result.setUniqueIdentifier(readCachedString(in, true));
 			result.setBundle(InternalPlatform.getDefault().getBundleContext().getBundle(in.readLong()));
 			result.setParent(readRegistry(in));
 			result.setHostIdentifier(readCachedString(in, false));

 			// now do extension points
 			int length = in.readInt();
 			IExtensionPoint[] extensionPoints = new ExtensionPoint[length];
 			for (int i = 0; i < length; i++)
 				extensionPoints[i] = readExtensionPoint(result, in);
 			result.setExtensionPoints(extensionPoints);

 			// and then extensions
 			length = in.readInt();
 			IExtension[] extensions = flushableExtensions ? new FlushableExtension[length] : new Extension[length];
 			for (int i = 0; i < length; i++)
 				extensions[i] = readExtension(in);
 			result.setExtensions(extensions);
 			return result;
 		} catch (IOException e) {
 			String bundleId = (result == null || result.getUniqueIdentifier() == null) ? "<not available>" : result.getUniqueIdentifier(); //$NON-NLS-1$
 			throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "plugin: " + bundleId), e); //$NON-NLS-1$//$NON-NLS-2$
 		}
 	}

 	private ExtensionRegistry readCache(DataInputStream in, long expectedTimestamps) throws InvalidRegistryCacheException {
 		if (!readHeaderInformation(in, expectedTimestamps)) {
 			if (InternalPlatform.DEBUG_REGISTRY)
 				debug("Cache header information out of date - ignoring cache"); //$NON-NLS-1$
 			return null;
 		}
 		return readRegistry(in);
 	}

 	private ExtensionRegistry readRegistry(DataInputStream in) throws InvalidRegistryCacheException {
 		try {
 			ExtensionRegistry result = (ExtensionRegistry) readIndex(in);
 			if (result != null)
 				return result;

 			result = new ExtensionRegistry();
 			if (lazilyLoadExtensions)
 				result.setCacheReader(this);
 			addToObjectTable(result);
 			// if there are no plugins in the registry, return null instead of
 			// an empty registry?
 			int length = in.readInt();
 			if (length == 0)
 				return null;
 			for (int i = 0; i < length; i++)
 				result.basicAdd(readBundleModel(in), false);
 			if (lazilyLoadExtensions)
 				result.setCacheReader(this);
 			return result;
 		} catch (IOException e) {
 			throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "ExtensionRegistry"), e); //$NON-NLS-1$//$NON-NLS-2$
 		}
 	}

 	private ConfigurationElement[] readSubElements(Extension parent, DataInputStream in) throws IOException {
 		int type = in.readByte();
 		if (type == NULL)
 			return null;

 		//Here type is OBJECT
 		// the first field is extension sub-elements data offset
 		int offset = in.readInt();

 		if (lazilyLoadExtensions) {
 			Extension extension = parent;
 			extension.setSubElementsCacheOffset(offset);
 			skipBasicSubElements(parent, in);
 			extension.setFullyLoaded(false);
 			return null;
 		}
 		return readBasicSubElements(parent, in);
 	}

 	private void skipBasicSubElements(Extension parent, DataInputStream in) throws IOException {
 		int length = in.readInt();
 		for (int i = 0; i < length; i++) {
 			skipConfigurationElement(parent, in);
 		}
 	}

 	private ConfigurationElement[] readBasicSubElements(Extension parent, DataInputStream in) throws IOException {
 		// read the number of sub elements to load
 		int length = in.readInt();

 		ConfigurationElement[] result = new ConfigurationElement[length];
 		for (int i = 0; i < length; i++) {
 			result[i] = readConfigurationElement(parent, in);
 		}
 		return result;
 	}

 	private String readString(DataInputStream in, boolean intern) throws IOException {
 		byte type = in.readByte();
 		if (type == NULL)
 			return null;
 		if (intern)
 			return in.readUTF().intern();
 		else
 			return in.readUTF();
 	}

 	private void skipString(DataInputStream in) throws IOException {
 		byte type = in.readByte();
 		if (type == NULL)
 			return;
 		int utfLength = in.readUnsignedShort();
 		byte bytearr[] = new byte[utfLength];
 		in.readFully(bytearr, 0, utfLength);
 	}

 	private String readCachedString(DataInputStream in, boolean intern) throws IOException {
 		byte type = in.readByte();
 		if (type == NULL)
 			return null;

 		if (type == INDEX)
 			return (String) objectTable.get(in.readInt());

 		String stringRead = null;
 		if (intern)
 			stringRead = in.readUTF().intern();
 		else
 			stringRead = in.readUTF();
 		addToObjectTable(stringRead);
 		return stringRead;
 	}

 	private Object readIndex(DataInputStream in) throws IOException {
 		byte type = in.readByte();
 		return type == INDEX ? objectTable.get(in.readInt()) : null;
 	}

 	private DataInputStream openCacheFile() throws IOException {
 		return new DataInputStream(new BufferedInputStream(new FileInputStream(cacheFile), 2048));
 	}

 	/**
 	 * Lazily loads an extension model's sub-elements.
 	 */
 	public final ConfigurationElement[] loadConfigurationElements(Extension parent, int offset) {
 		DataInputStream in = null;
 		try {
 			in = openCacheFile();
 			in.skipBytes(offset);
 			in.readInt(); // skip the offset itself
 			return readBasicSubElements(parent, in);
 		} catch (IOException e) {
 			Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e : null;
 			String message = Policy.bind("meta.unableToReadCache"); //$NON-NLS-1$
 			InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, exception));
 		} catch (OutOfMemoryError oome) {
 			// catch any OutOfMemoryErrors that may have been caused by corrupted data
 			logError(oome);
 		} catch (RuntimeException re) {
 			// catch any ArrayIndexOutOfBounds/NullPointer/NegativeArraySize/... exceptions that may have been caused by corrupted data
 			logError(re);
 		} finally {
 			try {
 				if (in != null)
 					in.close();
 			} catch (IOException e) {
 				// ignore
 			}
 		}
 		// we only get here when we have problems
 		failed = true;
 		return new ConfigurationElement[0];
 	}

 	boolean hasFailed() {
 		return failed;
 	}

 	private void logError(Throwable t) {
 		// log general message
 		String message = Policy.bind("meta.registryCacheReadProblems"); //$NON-NLS-1$
 		InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, null));
 		// log actual error
 		Throwable exceptionToLog = InternalPlatform.DEBUG_REGISTRY ? t : null;
 		InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, t.toString(), exceptionToLog));
 	}

 	public final ExtensionRegistry loadCache() {
 		return this.loadCache(0);
 	}

 	/*
 	 * If expectedTimestamp != 0, check it against the registry timestamp if the header.
 	 */
 	public final ExtensionRegistry loadCache(long expectedTimestamp) {
 		DataInputStream in = null;
 		try {
 			in = openCacheFile();
 		} catch (IOException e) {
 			Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e : null;
 			String message = Policy.bind("meta.unableToReadCache"); //$NON-NLS-1$
 			InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, exception));
 			return null;
 		}
 		try {
 			return readCache(in, expectedTimestamp);
 		} catch (InvalidRegistryCacheException e) {
 			Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e.getCause() : null;
 			InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, e.getMessage(), exception));
 		} catch (OutOfMemoryError oome) {
 			// catch any OutOfMemoryErrors that may have been caused by corrupted data
 			logError(oome);
 		} catch (RuntimeException re) {
 			// catch any ArrayIndexOutOfBounds/NullPointer/NegativeArraySize/... exceptions that may have been caused by corrupted data
 			logError(re);
 		} finally {
 			try {
 				if (in != null)
 					in.close();
 			} catch (IOException e) {
 				// ignore
 			}
 		}
 		return null;
 	}

 	public class InvalidRegistryCacheException extends Exception {
 		/**
 		 * All serializable objects should have a stable serialVersionUID
 		 */
 		private static final long serialVersionUID = 1L;

 		Throwable cause = null;

 		public InvalidRegistryCacheException(String msg, Throwable cause) {
 			super(msg);
 			this.cause = cause;
 		}

 		public InvalidRegistryCacheException(String string) {
 			super(string);
 		}

 		public Throwable getCause() {
 			return cause;
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2004 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/

	package org.eclipse.core.internal.registry;

	import java.io.*;
	import java.util.ArrayList;
	import java.util.List;
	import org.eclipse.core.internal.runtime.InternalPlatform;
	import org.eclipse.core.internal.runtime.Policy;
	import org.eclipse.core.runtime.*;

	/**
	* Failure reporting strategy:
	* - when reading an identified element (bundles, extension points and extensions),
	* catch any IOExceptions and rethrow them wrapped into a InvalidRegistryCacheException
	* that describes where the error happened
	* - IOExceptions while reading non-identified elements (configuration elements and properties)
	* are just propagated to their callers
	* - the public entry points will catch any exceptions to ensure they are logged and return a valid
	* value instead (for instance, a null reference or an empty array)
	*/
	public class RegistryCacheReader {

	MultiStatus problems = null;
	// objectTable will be an array list of objects. The objects will be things
	// like a plugin descriptor, extension point, etc. The integer
	// index value will be used in the cache to allow cross-references in the
	// cached registry.
	protected List objectTable = null;
	private boolean lazilyLoadExtensions;
	private boolean flushableExtensions = true;
	// indicates we failed load configuration elements lazily
	private boolean failed;
	protected File cacheFile;

	public static final byte REGISTRY_CACHE_VERSION = 7;
	public static final byte NULL = 0;
	public static final byte OBJECT = 1;
	public static final byte INDEX = 2;

	public RegistryCacheReader(File cacheFile, MultiStatus problems, boolean lazilyLoadExtensions, boolean flushable) {
	super();
	this.cacheFile = cacheFile;
	this.problems = problems;
	this.lazilyLoadExtensions = lazilyLoadExtensions;
	this.flushableExtensions = flushable;
	objectTable = new ArrayList();
	}

	public RegistryCacheReader(File cacheFile, MultiStatus problems) {
	this(cacheFile, problems, false, true);
	}

	private int addToObjectTable(Object object) {
	objectTable.add(object);
	// return the index of the object just added (i.e. size - 1)
	return (objectTable.size() - 1);
	}

	private void debug(String msg) {
	System.out.println("RegistryCacheReader: " + msg); //$NON-NLS-1$
	}

	private boolean readHeaderInformation(DataInputStream in, long expectedTimestamp) throws InvalidRegistryCacheException {
	try {
	if (in.readInt() != REGISTRY_CACHE_VERSION)
	return false;
	long installStamp = in.readLong();
	long registryStamp = in.readLong();
	String osStamp = in.readUTF();
	String windowsStamp = in.readUTF();
	String localeStamp = in.readUTF();
	InternalPlatform info = InternalPlatform.getDefault();
	return ((expectedTimestamp == 0 \|\| expectedTimestamp == registryStamp) && (installStamp == info.getStateTimeStamp()) && (osStamp.equals(info.getOS())) && (windowsStamp.equals(info.getWS())) && (localeStamp.equals(info.getNL())));
	} catch (IOException e) {
	throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "HeaderInformation"), e); //$NON-NLS-1$//$NON-NLS-2$
	}
	}

	private void skipConfigurationElement(RegistryModelObject parent, DataInputStream in) throws IOException {
	readCachedString(in, false); //read name
	skipString(in); //skip value

	int length = in.readInt();
	for (int i = 0; i < length; i++) {
	skipConfigurationProperty(in);
	}
	length = in.readInt();
	for (int i = 0; i < length; i++) {
	skipConfigurationElement(null, in);
	}
	}

	private ConfigurationElement readConfigurationElement(RegistryModelObject parent, DataInputStream in) throws IOException {
	ConfigurationElement result = new ConfigurationElement();
	result.setParent(parent);
	result.setName(readCachedString(in, false));
	result.setValue(readString(in, false));

	int length = in.readInt();
	ConfigurationProperty[] properties = new ConfigurationProperty[length];
	for (int i = 0; i < length; i++) {
	properties[i] = readConfigurationProperty(in);
	}
	result.setProperties(properties);

	length = in.readInt();
	IConfigurationElement[] elements = new ConfigurationElement[length];
	for (int i = 0; i < length; i++) {
	elements[i] = readConfigurationElement(result, in);
	}
	result.setChildren(elements);
	return result;
	}

	private void skipConfigurationProperty(DataInputStream in) throws IOException {
	readCachedString(in, false); //Read the name
	skipString(in); // skip the value
	}

	private ConfigurationProperty readConfigurationProperty(DataInputStream in) throws IOException {
	String name = readCachedString(in, false);
	ConfigurationProperty result = new ConfigurationProperty();
	result.setName(name);
	result.setValue(readString(in, false));
	return result;
	}

	private Extension readExtension(DataInputStream in) throws InvalidRegistryCacheException {
	Extension result = null;
	try {
	result = (Extension) readIndex(in);
	if (result != null)
	return result;
	result = flushableExtensions ? new FlushableExtension() : new Extension();
	addToObjectTable(result);
	result.setSimpleIdentifier(readString(in, false));
	result.setParent(readBundleModel(in));
	result.setName(readString(in, false));
	result.setExtensionPointIdentifier(readCachedString(in, false));
	result.setSubElements(readSubElements(result, in));
	return result;
	} catch (IOException e) {
	String extensionId = null;
	if (result != null && result.getParent() != null)
	extensionId = result.getParentIdentifier() + "." + result.getSimpleIdentifier(); //$NON-NLS-1$
	throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "extension: " + extensionId), e); //$NON-NLS-1$ //$NON-NLS-2$
	}
	}

	private ExtensionPoint readExtensionPoint(Namespace bundle, DataInputStream in) throws InvalidRegistryCacheException {
	ExtensionPoint result = null;
	try {
	result = (ExtensionPoint) readIndex(in);
	if (result != null)
	return result;
	result = new ExtensionPoint();
	addToObjectTable(result);
	result.setParent(bundle);
	result.setSimpleIdentifier(readString(in, true));
	result.setName(readString(in, false));
	result.setSchema(readString(in, false));

	// Now do the extensions.
	int length = in.readInt();
	IExtension[] extensions = new Extension[length];
	for (int i = 0; i < length; i++)
	extensions[i] = readExtension(in);
	result.setExtensions(extensions);
	return result;
	} catch (IOException e) {
	String extensionPointId = null;
	if (result != null && result.getParent() != null)
	extensionPointId = result.getUniqueIdentifier();
	throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "extension point: " + extensionPointId), e); //$NON-NLS-1$ //$NON-NLS-2$
	}
	}

	private Namespace readBundleModel(DataInputStream in) throws InvalidRegistryCacheException {
	Namespace result = null;
	try {
	result = (Namespace) readIndex(in);
	if (result != null)
	return result;
	result = new Namespace();
	addToObjectTable(result);
	result.setUniqueIdentifier(readCachedString(in, true));
	result.setBundle(InternalPlatform.getDefault().getBundleContext().getBundle(in.readLong()));
	result.setParent(readRegistry(in));
	result.setHostIdentifier(readCachedString(in, false));

	// now do extension points
	int length = in.readInt();
	IExtensionPoint[] extensionPoints = new ExtensionPoint[length];
	for (int i = 0; i < length; i++)
	extensionPoints[i] = readExtensionPoint(result, in);
	result.setExtensionPoints(extensionPoints);

	// and then extensions
	length = in.readInt();
	IExtension[] extensions = flushableExtensions ? new FlushableExtension[length] : new Extension[length];
	for (int i = 0; i < length; i++)
	extensions[i] = readExtension(in);
	result.setExtensions(extensions);
	return result;
	} catch (IOException e) {
	String bundleId = (result == null \|\| result.getUniqueIdentifier() == null) ? "<not available>" : result.getUniqueIdentifier(); //$NON-NLS-1$
	throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "plugin: " + bundleId), e); //$NON-NLS-1$//$NON-NLS-2$
	}
	}

	private ExtensionRegistry readCache(DataInputStream in, long expectedTimestamps) throws InvalidRegistryCacheException {
	if (!readHeaderInformation(in, expectedTimestamps)) {
	if (InternalPlatform.DEBUG_REGISTRY)
	debug("Cache header information out of date - ignoring cache"); //$NON-NLS-1$
	return null;
	}
	return readRegistry(in);
	}

	private ExtensionRegistry readRegistry(DataInputStream in) throws InvalidRegistryCacheException {
	try {
	ExtensionRegistry result = (ExtensionRegistry) readIndex(in);
	if (result != null)
	return result;

	result = new ExtensionRegistry();
	if (lazilyLoadExtensions)
	result.setCacheReader(this);
	addToObjectTable(result);
	// if there are no plugins in the registry, return null instead of
	// an empty registry?
	int length = in.readInt();
	if (length == 0)
	return null;
	for (int i = 0; i < length; i++)
	result.basicAdd(readBundleModel(in), false);
	if (lazilyLoadExtensions)
	result.setCacheReader(this);
	return result;
	} catch (IOException e) {
	throw new InvalidRegistryCacheException(Policy.bind("meta.regCacheIOExceptionReading", "ExtensionRegistry"), e); //$NON-NLS-1$//$NON-NLS-2$
	}
	}

	private ConfigurationElement[] readSubElements(Extension parent, DataInputStream in) throws IOException {
	int type = in.readByte();
	if (type == NULL)
	return null;

	//Here type is OBJECT
	// the first field is extension sub-elements data offset
	int offset = in.readInt();

	if (lazilyLoadExtensions) {
	Extension extension = parent;
	extension.setSubElementsCacheOffset(offset);
	skipBasicSubElements(parent, in);
	extension.setFullyLoaded(false);
	return null;
	}
	return readBasicSubElements(parent, in);
	}

	private void skipBasicSubElements(Extension parent, DataInputStream in) throws IOException {
	int length = in.readInt();
	for (int i = 0; i < length; i++) {
	skipConfigurationElement(parent, in);
	}
	}

	private ConfigurationElement[] readBasicSubElements(Extension parent, DataInputStream in) throws IOException {
	// read the number of sub elements to load
	int length = in.readInt();

	ConfigurationElement[] result = new ConfigurationElement[length];
	for (int i = 0; i < length; i++) {
	result[i] = readConfigurationElement(parent, in);
	}
	return result;
	}

	private String readString(DataInputStream in, boolean intern) throws IOException {
	byte type = in.readByte();
	if (type == NULL)
	return null;
	if (intern)
	return in.readUTF().intern();
	else
	return in.readUTF();
	}

	private void skipString(DataInputStream in) throws IOException {
	byte type = in.readByte();
	if (type == NULL)
	return;
	int utfLength = in.readUnsignedShort();
	byte bytearr[] = new byte[utfLength];
	in.readFully(bytearr, 0, utfLength);
	}

	private String readCachedString(DataInputStream in, boolean intern) throws IOException {
	byte type = in.readByte();
	if (type == NULL)
	return null;

	if (type == INDEX)
	return (String) objectTable.get(in.readInt());

	String stringRead = null;
	if (intern)
	stringRead = in.readUTF().intern();
	else
	stringRead = in.readUTF();
	addToObjectTable(stringRead);
	return stringRead;
	}

	private Object readIndex(DataInputStream in) throws IOException {
	byte type = in.readByte();
	return type == INDEX ? objectTable.get(in.readInt()) : null;
	}

	private DataInputStream openCacheFile() throws IOException {
	return new DataInputStream(new BufferedInputStream(new FileInputStream(cacheFile), 2048));
	}

	/**
	* Lazily loads an extension model's sub-elements.
	*/
	public final ConfigurationElement[] loadConfigurationElements(Extension parent, int offset) {
	DataInputStream in = null;
	try {
	in = openCacheFile();
	in.skipBytes(offset);
	in.readInt(); // skip the offset itself
	return readBasicSubElements(parent, in);
	} catch (IOException e) {
	Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e : null;
	String message = Policy.bind("meta.unableToReadCache"); //$NON-NLS-1$
	InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, exception));
	} catch (OutOfMemoryError oome) {
	// catch any OutOfMemoryErrors that may have been caused by corrupted data
	logError(oome);
	} catch (RuntimeException re) {
	// catch any ArrayIndexOutOfBounds/NullPointer/NegativeArraySize/... exceptions that may have been caused by corrupted data
	logError(re);
	} finally {
	try {
	if (in != null)
	in.close();
	} catch (IOException e) {
	// ignore
	}
	}
	// we only get here when we have problems
	failed = true;
	return new ConfigurationElement[0];
	}

	boolean hasFailed() {
	return failed;
	}

	private void logError(Throwable t) {
	// log general message
	String message = Policy.bind("meta.registryCacheReadProblems"); //$NON-NLS-1$
	InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, null));
	// log actual error
	Throwable exceptionToLog = InternalPlatform.DEBUG_REGISTRY ? t : null;
	InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, t.toString(), exceptionToLog));
	}

	public final ExtensionRegistry loadCache() {
	return this.loadCache(0);
	}

	/*
	* If expectedTimestamp != 0, check it against the registry timestamp if the header.
	*/
	public final ExtensionRegistry loadCache(long expectedTimestamp) {
	DataInputStream in = null;
	try {
	in = openCacheFile();
	} catch (IOException e) {
	Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e : null;
	String message = Policy.bind("meta.unableToReadCache"); //$NON-NLS-1$
	InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, message, exception));
	return null;
	}
	try {
	return readCache(in, expectedTimestamp);
	} catch (InvalidRegistryCacheException e) {
	Throwable exception = InternalPlatform.DEBUG_REGISTRY ? e.getCause() : null;
	InternalPlatform.getDefault().log(new Status(IStatus.WARNING, Platform.PI_RUNTIME, 0, e.getMessage(), exception));
	} catch (OutOfMemoryError oome) {
	// catch any OutOfMemoryErrors that may have been caused by corrupted data
	logError(oome);
	} catch (RuntimeException re) {
	// catch any ArrayIndexOutOfBounds/NullPointer/NegativeArraySize/... exceptions that may have been caused by corrupted data
	logError(re);
	} finally {
	try {
	if (in != null)
	in.close();
	} catch (IOException e) {
	// ignore
	}
	}
	return null;
	}

	public class InvalidRegistryCacheException extends Exception {
	/**
	* All serializable objects should have a stable serialVersionUID
	*/
	private static final long serialVersionUID = 1L;

	Throwable cause = null;

	public InvalidRegistryCacheException(String msg, Throwable cause) {
	super(msg);
	this.cause = cause;
	}

	public InvalidRegistryCacheException(String string) {
	super(string);
	}

	public Throwable getCause() {
	return cause;
	}
	}
	}