plugins/org.eclipse.objectteams.otequinox/src/org/eclipse/objectteams/internal/osgi/weaving/OTWeavingHook.java - objectteams/org.eclipse.objectteams - Git at Google

 /**********************************************************************
  * This file is part of "Object Teams Development Tooling"-Software
  *
  * Copyright 2013, 2015 GK Software AG
  *
  * 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
  *
  * Please visit http://www.eclipse.org/objectteams for updates and contact.
  *
  * Contributors:
  * 	Stephan Herrmann - Initial API and implementation
  **********************************************************************/
 package org.eclipse.objectteams.internal.osgi.weaving;

 import static org.eclipse.objectteams.otequinox.Constants.LIFTING_PARTICIPANT_EXTPOINT_ID;
 import static org.eclipse.objectteams.otequinox.Constants.TRANSFORMER_PLUGIN_ID;
 import static org.eclipse.objectteams.otequinox.Constants.ORG_OBJECTTEAMS_TEAM;
 import static org.eclipse.objectteams.otequinox.TransformerPlugin.log;

 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.instrument.IllegalClassFormatException;
 import java.lang.reflect.Field;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;

 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExtensionRegistry;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.jdt.annotation.NonNull;
 import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.objectteams.internal.osgi.weaving.ASMByteCodeAnalyzer.ClassInformation;
 import org.eclipse.objectteams.internal.osgi.weaving.AspectBinding.BaseBundle;
 import org.eclipse.objectteams.internal.osgi.weaving.AspectBinding.TeamBinding;
 import org.eclipse.objectteams.internal.osgi.weaving.Util.ProfileKind;
 import org.eclipse.objectteams.internal.osgi.weaving.AspectPermissionManager;
 import org.eclipse.objectteams.otequinox.Constants;
 import org.eclipse.objectteams.otequinox.TransformerPlugin;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.ServiceReference;
 import org.osgi.framework.hooks.weaving.WeavingHook;
 import org.osgi.framework.hooks.weaving.WovenClass;
 import org.osgi.framework.hooks.weaving.WovenClassListener;
 import org.osgi.framework.namespace.PackageNamespace;
 import org.osgi.framework.wiring.BundleWiring;
 import org.osgi.resource.Wire;

 /**
  * This class integrates the OT/J weaver into OSGi using the standard API {@link WeavingHook}.
  * <p>
  * Additionally, we listen to events of woven classes changing to state {@link WovenClass#DEFINED}:
  * </p>
  * <ul>
  * <li>Given that {@link AspectBindingRegistry#addDeferredTeamClasses} was used to record
  * teams that could not be instantiated due to some required class being reported
  * as {@link NoClassDefFoundError}.</li>
  * <li>Assuming further that this error happened because the required class was in the process
  * of being loaded further down the call stack.</li>
  * <li>If later one of the not-found classes has been defined we use that trigger to
  * re-attempt instantiating the dependent team(s).</li>
  * </ul>
  */
 public class OTWeavingHook implements WeavingHook, WovenClassListener {


 	// TODO: this master-switch, which selects the weaver, should probably be replaced by s.t. else?
 	boolean useDynamicWeaver = "dynamic".equals(System.getProperty("ot.weaving"));

 	// TODO: temporary switch to fall back to coarse grain checking:
 	boolean skipBaseClassCheck = "skip".equals(System.getProperty("otequinox.baseClassChecks"));

 	// for installing a lifting participant:
 	private static final String LIFTING_PARTICIPANT_FIELD = "_OT$liftingParticipant";

 	enum WeavingReason { None, Aspect, Base, Thread }

 	/** Interface to data about aspectBinding extensions. */
 	private @NonNull AspectBindingRegistry aspectBindingRegistry = new AspectBindingRegistry();

 	/** Map of trip wires to be fired when a particular base bundle is loaded. */
 	private @NonNull HashMap<String, BaseBundleLoadTrigger> baseTripWires = new HashMap<>();

 	/** Set of classes for which processing has started but which are not yet defined in the class loader. */
 	private @NonNull Set<String> beingDefined = new HashSet<>();

 	/** Records of teams that have been deferred due to unresolved class dependencies: */
 	private @NonNull List<WaitingTeamRecord> deferredTeams = new ArrayList<>();

 	private @NonNull ASMByteCodeAnalyzer byteCodeAnalyzer = new ASMByteCodeAnalyzer();

 	private AspectPermissionManager permissionManager;

 	/** A registered lifting participant is directly handled by us. */
 	private @Nullable IConfigurationElement liftingParticipantConfig;
 	private @Nullable Class<?> ooTeam;

 	/** Call-back once the extension registry is up and running. */
 	public void activate(BundleContext bundleContext, ServiceReference<IExtensionRegistry> serviceReference) {
 		loadAspectBindingRegistry(bundleContext, serviceReference);
 		TransformerPlugin activator = TransformerPlugin.getDefault();
 		activator.registerAspectBindingRegistry(this.aspectBindingRegistry);
 		activator.registerAspectPermissionManager(this.permissionManager);
 	}

 	// ====== Aspect Bindings & Permissions: ======

 	@SuppressWarnings("deprecation")
 	private void loadAspectBindingRegistry(BundleContext context, ServiceReference<IExtensionRegistry> serviceReference) {
 		org.osgi.service.packageadmin.PackageAdmin packageAdmin = null;

 		ServiceReference<?> ref= context.getServiceReference(org.osgi.service.packageadmin.PackageAdmin.class.getName());
 		if (ref!=null)
 			packageAdmin = (org.osgi.service.packageadmin.PackageAdmin)context.getService(ref);
 		else
 			log(IStatus.ERROR, "Failed to load PackageAdmin service. Will not be able to handle fragments.");


 		IExtensionRegistry extensionRegistry = context.getService(serviceReference);
 		if (extensionRegistry == null) {
 			log(IStatus.ERROR, "Failed to acquire ExtensionRegistry service, cannot load aspect bindings.");
 		} else {
 			permissionManager = new AspectPermissionManager(context.getBundle(), packageAdmin); // known API
 			permissionManager.loadAspectBindingNegotiators(extensionRegistry);

 			aspectBindingRegistry.loadAspectBindings(extensionRegistry, packageAdmin, this);

 			loadLiftingParticipant(extensionRegistry);
 		}
 	}

 	public @NonNull AspectPermissionManager getAspectPermissionManager() {
 		AspectPermissionManager manager = this.permissionManager;
 		if (manager == null)
 			throw new NullPointerException("Missing AspectPermissionManager");
 		return manager;
 	}

 	/* Load extension for org.eclipse.objectteams.otequinox.liftingParticipant. */
 	private void loadLiftingParticipant(IExtensionRegistry extensionRegistry) {
 		IConfigurationElement[] liftingParticipantConfigs = extensionRegistry.getConfigurationElementsFor(
 				TRANSFORMER_PLUGIN_ID, LIFTING_PARTICIPANT_EXTPOINT_ID);

 		if (liftingParticipantConfigs.length != 1) {
 			if (liftingParticipantConfigs.length > 1)
 				log(IStatus.ERROR, "Cannot install more than one lifting participant.");
 			return;
 		}
 		this.liftingParticipantConfig = liftingParticipantConfigs[0];
 		installLiftingParticipant();
 	}

 	private void installLiftingParticipant() {
 		Class<?> teamClass = this.ooTeam;
 		IConfigurationElement config = this.liftingParticipantConfig;
 		if (teamClass != null && config != null) {
 			try {
 				Field field = teamClass.getDeclaredField(LIFTING_PARTICIPANT_FIELD); // field name cannot be mentioned in source
 				field.set(null, config.createExecutableExtension(Constants.CLASS));
 				log(IStatus.INFO, "Registered Lifting Participant from "+config.getContributor().getName());
 			} catch (Exception e) {
 				log(e, "Failed to install lifting participant from "+config.getContributor().getName());
 			}
 			this.liftingParticipantConfig = null; // signal done
 		}
 	}

 	// ====== Base Bundle Trip Wires: ======

 	/**
 	 * Callback during AspectBindingRegistry#loadAspectBindings():
 	 * Set-up a trip wire to fire when the mentioned base bundle is loaded.
 	 */
 	void setBaseTripWire(@SuppressWarnings("deprecation") @Nullable org.osgi.service.packageadmin.PackageAdmin packageAdmin,
 			@NonNull String baseBundleId, BaseBundle baseBundle)
 	{
 		if (!baseTripWires.containsKey(baseBundleId))
 			baseTripWires.put(baseBundleId, new BaseBundleLoadTrigger(baseBundleId, baseBundle, aspectBindingRegistry, packageAdmin));
 	}

 	/**
 	 * Check if the given base bundle / base class mandate any loading/instantiation/activation of teams.
 	 * @return true if all involved aspect bindings have been denied (permissions).
 	 */
 	boolean triggerBaseTripWires(@Nullable String bundleName, @NonNull WovenClass baseClass) {
 		BaseBundleLoadTrigger activation = baseTripWires.get(bundleName);
 		if (activation != null) {
 			activation.fire(baseClass, beingDefined, this);
 			if (activation.isDone())
 				baseTripWires.remove(bundleName);
 			return activation.areAllAspectsDenied();
 		}
 		return false;
 	}

 	// ====== Main Weaving Entry: ======

 	@Override
 	public void weave(WovenClass wovenClass) {
 		beingDefined.add(wovenClass.getClassName());

 		try {
 			BundleWiring bundleWiring = wovenClass.getBundleWiring();
 			String bundleName = bundleWiring.getBundle().getSymbolicName();
 			String className = wovenClass.getClassName();

 			if (bundleName.equals(Constants.TRANSFORMER_PLUGIN_ID)
 					|| bundleName.startsWith("org.eclipse.objectteams.otre") // incl. otredyn
 					|| bundleName.equals("org.objectweb.asm"))
 				return;

 			if (BCELPatcher.BCEL_PLUGIN_ID.equals(bundleName)) {
 				BCELPatcher.fixBCEL(wovenClass);
 				return;
 			}

 			byte[] bytes = wovenClass.getBytes();
 			WeavingReason reason = requiresWeaving(bundleWiring, className, bytes);
 			if (reason != WeavingReason.None) {
 				// do whatever is needed *before* loading this class:
 				boolean allAspectsAreDenied = triggerBaseTripWires(bundleName, wovenClass);
 				if (reason == WeavingReason.Base && allAspectsAreDenied) {
 					return; // don't weave for denied bindings
 				} else if (reason == WeavingReason.Thread) {
 					BaseBundle baseBundle = this.aspectBindingRegistry.getBaseBundle(bundleName);
 					BaseBundleLoadTrigger.addOTREImport(baseBundle, bundleName, wovenClass, this.useDynamicWeaver);
 				}

 				long time = 0;

 				DelegatingTransformer transformer = DelegatingTransformer.newTransformer(useDynamicWeaver, this, bundleWiring);
 				Class<?> classBeingRedefined = null; // TODO prepare for otre-dyn
 				try {
 					log(IStatus.OK, "About to transform class "+className);
 					time = 0;
 					if (Util.PROFILE) time= System.nanoTime();
 					byte[] newBytes = transformer.transform(bundleWiring.getBundle(),
 										className, classBeingRedefined, null/*protectionDomain*/, bytes);
 					if (newBytes != null && newBytes != bytes && !Arrays.equals(newBytes, bytes)) {
 						if (Util.PROFILE) Util.profile(time, ProfileKind.Transformation, className);
 						log(IStatus.INFO, "Transformation performed on "+className);
 						wovenClass.setBytes(newBytes);
 						if (reason == WeavingReason.Aspect)
 							recordBaseClasses(transformer, bundleName, className);
 					} else {
 						if (Util.PROFILE) Util.profile(time, ProfileKind.NoTransformation, className);
 					}
 				} catch (IllegalClassFormatException e) {
 					log(e, "Failed to transform class "+className);
 				}
 			}
 		} catch (ClassCircularityError cce) {
 			log(cce, "Weaver encountered a circular class dependency");
 		}
 	}

 	WeavingReason requiresWeaving(BundleWiring bundleWiring, String className, byte[] bytes) {

 		// 1. consult the aspect binding registry (for per-bundle info):
 		@SuppressWarnings("null")@NonNull // FIXME: org.eclipse.osgi.internal.resolver.BundleDescriptionImpl.getBundle() can return null!
 		Bundle bundle = bundleWiring.getBundle();
 		if (aspectBindingRegistry.getAdaptedBasePlugins(bundle) != null)
 			return WeavingReason.Aspect;

 		List<AspectBinding> aspectBindings = aspectBindingRegistry.getAdaptingAspectBindings(bundle.getSymbolicName());
 		if (aspectBindings != null && !aspectBindings.isEmpty()) {
 			// potential base class: look deeper:
 			for (AspectBinding aspectBinding : aspectBindings) {
 				if (!aspectBinding.hasScannedTeams && !aspectBinding.hasBeenDenied)
 					return WeavingReason.Base; // we may be first, go ahead and trigger the trip wire
 			}
 			if (isAdaptedBaseClass(aspectBindings, className, bytes, bundleWiring.getClassLoader()))
 				return WeavingReason.Base;
 		}

 		// 2. test for implementation of Runnable / Thread (per class):
 		long time = 0;
 		if (Util.PROFILE) time= System.nanoTime();
 		if (needsThreadNotificationCode(className, bytes, bundleWiring.getClassLoader()))
 			return WeavingReason.Thread;
 		if (Util.PROFILE) Util.profile(time, ProfileKind.SuperClassFetching, "");

 		return WeavingReason.None;
 	}

 	/** check need for weaving by finding an aspect binding affecting this exact base class or one of its supers. */
 	boolean isAdaptedBaseClass(List<AspectBinding> aspectBindings, String className, byte[] bytes, ClassLoader resourceLoader) {
 		if (skipBaseClassCheck) return true; // have aspect bindings, flag requests to transform *all* classes in this base bundle

 		if ("java.lang.Object".equals(className))
 			return false; // shortcut, not weavable nor do we have supers

 		long start = 0;
 		if (Util.PROFILE) start = System.nanoTime();

 		try {
 			for (AspectBinding aspectBinding : aspectBindings) {
 				if (aspectBinding.allBaseClassNames.contains(className) && !aspectBinding.hasBeenDenied)
 					return true;
 			}
 			// attempt recursion to superclass (not superInterfaces atm):
 			ClassInformation classInfo = null;
 			if (bytes != null) {
 				classInfo = this.byteCodeAnalyzer.getClassInformation(bytes, className);
 			} else {
 				try (InputStream is = resourceLoader.getResourceAsStream(className.replace('.', '/')+".class")) {
 					if (is != null)
 						classInfo = this.byteCodeAnalyzer.getClassInformation(is, className);
 				} catch (IOException e) {
 					return false;
 				}
 			}
 			if (classInfo != null && !classInfo.isInterface()) {
 				// TODO(performance): check common prefix to recognize when crossing the plugin-boundary?
 				return isAdaptedBaseClass(aspectBindings, classInfo.getSuperClassName(), null, resourceLoader);
 			}
 			return false;
 		} finally {
 			if (bytes != null && Util.PROFILE) { // only report at top invocation
 				Util.profile(start, ProfileKind.SuperClassFetching, className);
 			}
 		}
 	}

 	private void recordBaseClasses(DelegatingTransformer transformer, @NonNull String aspectBundle, String className) {
 		Collection<String> adaptedBases = transformer.fetchAdaptedBases();
 		if (adaptedBases == null || adaptedBases.isEmpty()) return;
 		List<AspectBinding> aspectBindings = aspectBindingRegistry.getAspectBindings(aspectBundle);
 		if (aspectBindings != null)
 			for (AspectBinding aspectBinding : aspectBindings)
 				if (!aspectBinding.hasScannedTeams)
 					for (TeamBinding team : aspectBinding.teams)
 						if (team.teamName.equals(className))
 							if (!team.hasScannedBases) {
 								for (TeamBinding equivalent : team.equivalenceSet) {
 									equivalent.addBaseClassNames(adaptedBases);
 									equivalent.hasScannedBases = true;
 								}
 								return; // done all equivalent teams
 							}
 	}

 	// ===== handling deferred teams: ======

 	/**
 	 * Record the given team classes as waiting for instantiation/activation.
 	 * Callback during {@link BaseBundleLoadTrigger#fire()}
 	 */
 	public void addDeferredTeamClasses(List<WaitingTeamRecord> teamClasses) {
 		synchronized (deferredTeams) {
 			deferredTeams.addAll(teamClasses);
 		}
 	}

 	/**
 	 * Try to instantiate/activate any deferred teams that may be unblocked
 	 * by the definition of the given trigger class.
 	 */
 	public void instantiateScheduledTeams(String triggerClassName) {
 		List<WaitingTeamRecord> scheduledTeams = null;
 		synchronized(deferredTeams) {
 			for (WaitingTeamRecord record : new ArrayList<>(deferredTeams)) {
 				if (record.notFoundClass.equals(triggerClassName)) {
 					if (scheduledTeams == null)
 						scheduledTeams = new ArrayList<>();
 					if (deferredTeams.remove(record))
 						scheduledTeams.add(record);
 				}
 			}
 		}
 		if (scheduledTeams == null) return;
 		for(WaitingTeamRecord record : scheduledTeams) {
 			if (record.team.isActivated)
 				continue;
 			String teamName = record.team.teamName;
 			log(IStatus.INFO, "Consider for instantiation/activation: team "+teamName);
 			try {
 				TeamLoader loader = new TeamLoader(deferredTeams, beingDefined, this.useDynamicWeaver);
 				// Instantiate (we only get here if activationKind != NONE)
 				loader.instantiateAndActivate(record.aspectBinding, record.team, record.activationKind); // may re-insert to deferredTeams
 			} catch (Exception e) {
 				log(e, "Failed to instantiate team "+teamName);
 				continue;
 			}
 		}
 	}

 	@Override
 	public void modified(WovenClass wovenClass) {
 		if (wovenClass.getState() == WovenClass.DEFINED) {
 			@NonNull String className = wovenClass.getClassName();
 			if (className.equals(ORG_OBJECTTEAMS_TEAM)) {
 				this.ooTeam = wovenClass.getDefinedClass();
 				installLiftingParticipant();
 			}
 			beingDefined.remove(className);
 			instantiateScheduledTeams(className);

 			TransformerPlugin.flushLog();
 		}
 	}

 	static boolean hasImport(WovenClass clazz, String packageName, String packageWithAttribute) {
 		List<String> imports = clazz.getDynamicImports();
 		for (String imp : imports)
 			if (imp.equals(packageName) || imp.equals(packageWithAttribute))
 				return true;
 		for (Wire wire : clazz.getBundleWiring().getRequiredResourceWires(PackageNamespace.PACKAGE_NAMESPACE)) {
 			Object packageValue = wire.getRequirement().getAttributes().get(PackageNamespace.PACKAGE_NAMESPACE);
 			if (packageName.equals(packageValue) || packageWithAttribute.equals(packageValue))
 				return true;
 		}
 		return false;

 	}

 	private boolean needsThreadNotificationCode(String className, byte[] bytes, ClassLoader resourceLoader) {

 		if ("java.lang.Object".equals(className))
 			return false; // shortcut, have no super
 		ClassInformation classInfo = null;
 		if (bytes != null) {
 			classInfo = this.byteCodeAnalyzer.getClassInformation(bytes, className);
 		} else {
 			try (InputStream is = resourceLoader.getResourceAsStream(className.replace('.', '/')+".class")) {
 				if (is != null) {
 					classInfo = this.byteCodeAnalyzer.getClassInformation(is, className);
 				}
 			} catch (IOException e) {
 				return false;
 			}
 		}
 		if (classInfo != null && !classInfo.isInterface()) {
 			String superClassName = classInfo.getSuperClassName();
 			if ("java.lang.Thread".equals(superClassName))
 				return true; // ensure TeamActivation will weave the calls to TeamThreadManager
 			String[] superInterfaceNames = classInfo.getSuperInterfaceNames();
 			if (superInterfaceNames != null)
 				for (int i = 0; i < superInterfaceNames.length; i++) {
 					if ("java.lang.Runnable".equals(superInterfaceNames[i]))
 						return true; // ensure TeamActivation will weave the calls to TeamThreadManager
 				}
 		}
 		return false;
 	}

 }
	/**********************************************************************
	* This file is part of "Object Teams Development Tooling"-Software
	*
	* Copyright 2013, 2015 GK Software AG
	*
	* 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
	*
	* Please visit http://www.eclipse.org/objectteams for updates and contact.
	*
	* Contributors:
	* Stephan Herrmann - Initial API and implementation
	**********************************************************************/
	package org.eclipse.objectteams.internal.osgi.weaving;

	import static org.eclipse.objectteams.otequinox.Constants.LIFTING_PARTICIPANT_EXTPOINT_ID;
	import static org.eclipse.objectteams.otequinox.Constants.TRANSFORMER_PLUGIN_ID;
	import static org.eclipse.objectteams.otequinox.Constants.ORG_OBJECTTEAMS_TEAM;
	import static org.eclipse.objectteams.otequinox.TransformerPlugin.log;

	import java.io.IOException;
	import java.io.InputStream;
	import java.lang.instrument.IllegalClassFormatException;
	import java.lang.reflect.Field;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Set;

	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExtensionRegistry;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.jdt.annotation.NonNull;
	import org.eclipse.jdt.annotation.Nullable;
	import org.eclipse.objectteams.internal.osgi.weaving.ASMByteCodeAnalyzer.ClassInformation;
	import org.eclipse.objectteams.internal.osgi.weaving.AspectBinding.BaseBundle;
	import org.eclipse.objectteams.internal.osgi.weaving.AspectBinding.TeamBinding;
	import org.eclipse.objectteams.internal.osgi.weaving.Util.ProfileKind;
	import org.eclipse.objectteams.internal.osgi.weaving.AspectPermissionManager;
	import org.eclipse.objectteams.otequinox.Constants;
	import org.eclipse.objectteams.otequinox.TransformerPlugin;
	import org.osgi.framework.Bundle;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.ServiceReference;
	import org.osgi.framework.hooks.weaving.WeavingHook;
	import org.osgi.framework.hooks.weaving.WovenClass;
	import org.osgi.framework.hooks.weaving.WovenClassListener;
	import org.osgi.framework.namespace.PackageNamespace;
	import org.osgi.framework.wiring.BundleWiring;
	import org.osgi.resource.Wire;

	/**
	* This class integrates the OT/J weaver into OSGi using the standard API {@link WeavingHook}.
	* <p>
	* Additionally, we listen to events of woven classes changing to state {@link WovenClass#DEFINED}:
	* </p>
	* <ul>
	* <li>Given that {@link AspectBindingRegistry#addDeferredTeamClasses} was used to record
	* teams that could not be instantiated due to some required class being reported
	* as {@link NoClassDefFoundError}.</li>
	* <li>Assuming further that this error happened because the required class was in the process
	* of being loaded further down the call stack.</li>
	* <li>If later one of the not-found classes has been defined we use that trigger to
	* re-attempt instantiating the dependent team(s).</li>
	* </ul>
	*/
	public class OTWeavingHook implements WeavingHook, WovenClassListener {


	// TODO: this master-switch, which selects the weaver, should probably be replaced by s.t. else?
	boolean useDynamicWeaver = "dynamic".equals(System.getProperty("ot.weaving"));

	// TODO: temporary switch to fall back to coarse grain checking:
	boolean skipBaseClassCheck = "skip".equals(System.getProperty("otequinox.baseClassChecks"));

	// for installing a lifting participant:
	private static final String LIFTING_PARTICIPANT_FIELD = "_OT$liftingParticipant";

	enum WeavingReason { None, Aspect, Base, Thread }

	/** Interface to data about aspectBinding extensions. */
	private @NonNull AspectBindingRegistry aspectBindingRegistry = new AspectBindingRegistry();

	/** Map of trip wires to be fired when a particular base bundle is loaded. */
	private @NonNull HashMap<String, BaseBundleLoadTrigger> baseTripWires = new HashMap<>();

	/** Set of classes for which processing has started but which are not yet defined in the class loader. */
	private @NonNull Set<String> beingDefined = new HashSet<>();

	/** Records of teams that have been deferred due to unresolved class dependencies: */
	private @NonNull List<WaitingTeamRecord> deferredTeams = new ArrayList<>();

	private @NonNull ASMByteCodeAnalyzer byteCodeAnalyzer = new ASMByteCodeAnalyzer();

	private AspectPermissionManager permissionManager;

	/** A registered lifting participant is directly handled by us. */
	private @Nullable IConfigurationElement liftingParticipantConfig;
	private @Nullable Class<?> ooTeam;

	/** Call-back once the extension registry is up and running. */
	public void activate(BundleContext bundleContext, ServiceReference<IExtensionRegistry> serviceReference) {
	loadAspectBindingRegistry(bundleContext, serviceReference);
	TransformerPlugin activator = TransformerPlugin.getDefault();
	activator.registerAspectBindingRegistry(this.aspectBindingRegistry);
	activator.registerAspectPermissionManager(this.permissionManager);
	}

	// ====== Aspect Bindings & Permissions: ======

	@SuppressWarnings("deprecation")
	private void loadAspectBindingRegistry(BundleContext context, ServiceReference<IExtensionRegistry> serviceReference) {
	org.osgi.service.packageadmin.PackageAdmin packageAdmin = null;

	ServiceReference<?> ref= context.getServiceReference(org.osgi.service.packageadmin.PackageAdmin.class.getName());
	if (ref!=null)
	packageAdmin = (org.osgi.service.packageadmin.PackageAdmin)context.getService(ref);
	else
	log(IStatus.ERROR, "Failed to load PackageAdmin service. Will not be able to handle fragments.");


	IExtensionRegistry extensionRegistry = context.getService(serviceReference);
	if (extensionRegistry == null) {
	log(IStatus.ERROR, "Failed to acquire ExtensionRegistry service, cannot load aspect bindings.");
	} else {
	permissionManager = new AspectPermissionManager(context.getBundle(), packageAdmin); // known API
	permissionManager.loadAspectBindingNegotiators(extensionRegistry);

	aspectBindingRegistry.loadAspectBindings(extensionRegistry, packageAdmin, this);

	loadLiftingParticipant(extensionRegistry);
	}
	}

	public @NonNull AspectPermissionManager getAspectPermissionManager() {
	AspectPermissionManager manager = this.permissionManager;
	if (manager == null)
	throw new NullPointerException("Missing AspectPermissionManager");
	return manager;
	}

	/* Load extension for org.eclipse.objectteams.otequinox.liftingParticipant. */
	private void loadLiftingParticipant(IExtensionRegistry extensionRegistry) {
	IConfigurationElement[] liftingParticipantConfigs = extensionRegistry.getConfigurationElementsFor(
	TRANSFORMER_PLUGIN_ID, LIFTING_PARTICIPANT_EXTPOINT_ID);

	if (liftingParticipantConfigs.length != 1) {
	if (liftingParticipantConfigs.length > 1)
	log(IStatus.ERROR, "Cannot install more than one lifting participant.");
	return;
	}
	this.liftingParticipantConfig = liftingParticipantConfigs[0];
	installLiftingParticipant();
	}

	private void installLiftingParticipant() {
	Class<?> teamClass = this.ooTeam;
	IConfigurationElement config = this.liftingParticipantConfig;
	if (teamClass != null && config != null) {
	try {
	Field field = teamClass.getDeclaredField(LIFTING_PARTICIPANT_FIELD); // field name cannot be mentioned in source
	field.set(null, config.createExecutableExtension(Constants.CLASS));
	log(IStatus.INFO, "Registered Lifting Participant from "+config.getContributor().getName());
	} catch (Exception e) {
	log(e, "Failed to install lifting participant from "+config.getContributor().getName());
	}
	this.liftingParticipantConfig = null; // signal done
	}
	}

	// ====== Base Bundle Trip Wires: ======

	/**
	* Callback during AspectBindingRegistry#loadAspectBindings():
	* Set-up a trip wire to fire when the mentioned base bundle is loaded.
	*/
	void setBaseTripWire(@SuppressWarnings("deprecation") @Nullable org.osgi.service.packageadmin.PackageAdmin packageAdmin,
	@NonNull String baseBundleId, BaseBundle baseBundle)
	{
	if (!baseTripWires.containsKey(baseBundleId))
	baseTripWires.put(baseBundleId, new BaseBundleLoadTrigger(baseBundleId, baseBundle, aspectBindingRegistry, packageAdmin));
	}

	/**
	* Check if the given base bundle / base class mandate any loading/instantiation/activation of teams.
	* @return true if all involved aspect bindings have been denied (permissions).
	*/
	boolean triggerBaseTripWires(@Nullable String bundleName, @NonNull WovenClass baseClass) {
	BaseBundleLoadTrigger activation = baseTripWires.get(bundleName);
	if (activation != null) {
	activation.fire(baseClass, beingDefined, this);
	if (activation.isDone())
	baseTripWires.remove(bundleName);
	return activation.areAllAspectsDenied();
	}
	return false;
	}

	// ====== Main Weaving Entry: ======

	@Override
	public void weave(WovenClass wovenClass) {
	beingDefined.add(wovenClass.getClassName());

	try {
	BundleWiring bundleWiring = wovenClass.getBundleWiring();
	String bundleName = bundleWiring.getBundle().getSymbolicName();
	String className = wovenClass.getClassName();

	if (bundleName.equals(Constants.TRANSFORMER_PLUGIN_ID)
	\|\| bundleName.startsWith("org.eclipse.objectteams.otre") // incl. otredyn
	\|\| bundleName.equals("org.objectweb.asm"))
	return;

	if (BCELPatcher.BCEL_PLUGIN_ID.equals(bundleName)) {
	BCELPatcher.fixBCEL(wovenClass);
	return;
	}

	byte[] bytes = wovenClass.getBytes();
	WeavingReason reason = requiresWeaving(bundleWiring, className, bytes);
	if (reason != WeavingReason.None) {
	// do whatever is needed before loading this class:
	boolean allAspectsAreDenied = triggerBaseTripWires(bundleName, wovenClass);
	if (reason == WeavingReason.Base && allAspectsAreDenied) {
	return; // don't weave for denied bindings
	} else if (reason == WeavingReason.Thread) {
	BaseBundle baseBundle = this.aspectBindingRegistry.getBaseBundle(bundleName);
	BaseBundleLoadTrigger.addOTREImport(baseBundle, bundleName, wovenClass, this.useDynamicWeaver);
	}

	long time = 0;

	DelegatingTransformer transformer = DelegatingTransformer.newTransformer(useDynamicWeaver, this, bundleWiring);
	Class<?> classBeingRedefined = null; // TODO prepare for otre-dyn
	try {
	log(IStatus.OK, "About to transform class "+className);
	time = 0;
	if (Util.PROFILE) time= System.nanoTime();
	byte[] newBytes = transformer.transform(bundleWiring.getBundle(),
	className, classBeingRedefined, null/protectionDomain/, bytes);
	if (newBytes != null && newBytes != bytes && !Arrays.equals(newBytes, bytes)) {
	if (Util.PROFILE) Util.profile(time, ProfileKind.Transformation, className);
	log(IStatus.INFO, "Transformation performed on "+className);
	wovenClass.setBytes(newBytes);
	if (reason == WeavingReason.Aspect)
	recordBaseClasses(transformer, bundleName, className);
	} else {
	if (Util.PROFILE) Util.profile(time, ProfileKind.NoTransformation, className);
	}
	} catch (IllegalClassFormatException e) {
	log(e, "Failed to transform class "+className);
	}
	}
	} catch (ClassCircularityError cce) {
	log(cce, "Weaver encountered a circular class dependency");
	}
	}

	WeavingReason requiresWeaving(BundleWiring bundleWiring, String className, byte[] bytes) {

	// 1. consult the aspect binding registry (for per-bundle info):
	@SuppressWarnings("null")@NonNull // FIXME: org.eclipse.osgi.internal.resolver.BundleDescriptionImpl.getBundle() can return null!
	Bundle bundle = bundleWiring.getBundle();
	if (aspectBindingRegistry.getAdaptedBasePlugins(bundle) != null)
	return WeavingReason.Aspect;

	List<AspectBinding> aspectBindings = aspectBindingRegistry.getAdaptingAspectBindings(bundle.getSymbolicName());
	if (aspectBindings != null && !aspectBindings.isEmpty()) {
	// potential base class: look deeper:
	for (AspectBinding aspectBinding : aspectBindings) {
	if (!aspectBinding.hasScannedTeams && !aspectBinding.hasBeenDenied)
	return WeavingReason.Base; // we may be first, go ahead and trigger the trip wire
	}
	if (isAdaptedBaseClass(aspectBindings, className, bytes, bundleWiring.getClassLoader()))
	return WeavingReason.Base;
	}

	// 2. test for implementation of Runnable / Thread (per class):
	long time = 0;
	if (Util.PROFILE) time= System.nanoTime();
	if (needsThreadNotificationCode(className, bytes, bundleWiring.getClassLoader()))
	return WeavingReason.Thread;
	if (Util.PROFILE) Util.profile(time, ProfileKind.SuperClassFetching, "");

	return WeavingReason.None;
	}

	/** check need for weaving by finding an aspect binding affecting this exact base class or one of its supers. */
	boolean isAdaptedBaseClass(List<AspectBinding> aspectBindings, String className, byte[] bytes, ClassLoader resourceLoader) {
	if (skipBaseClassCheck) return true; // have aspect bindings, flag requests to transform all classes in this base bundle

	if ("java.lang.Object".equals(className))
	return false; // shortcut, not weavable nor do we have supers

	long start = 0;
	if (Util.PROFILE) start = System.nanoTime();

	try {
	for (AspectBinding aspectBinding : aspectBindings) {
	if (aspectBinding.allBaseClassNames.contains(className) && !aspectBinding.hasBeenDenied)
	return true;
	}
	// attempt recursion to superclass (not superInterfaces atm):
	ClassInformation classInfo = null;
	if (bytes != null) {
	classInfo = this.byteCodeAnalyzer.getClassInformation(bytes, className);
	} else {
	try (InputStream is = resourceLoader.getResourceAsStream(className.replace('.', '/')+".class")) {
	if (is != null)
	classInfo = this.byteCodeAnalyzer.getClassInformation(is, className);
	} catch (IOException e) {
	return false;
	}
	}
	if (classInfo != null && !classInfo.isInterface()) {
	// TODO(performance): check common prefix to recognize when crossing the plugin-boundary?
	return isAdaptedBaseClass(aspectBindings, classInfo.getSuperClassName(), null, resourceLoader);
	}
	return false;
	} finally {
	if (bytes != null && Util.PROFILE) { // only report at top invocation
	Util.profile(start, ProfileKind.SuperClassFetching, className);
	}
	}
	}

	private void recordBaseClasses(DelegatingTransformer transformer, @NonNull String aspectBundle, String className) {
	Collection<String> adaptedBases = transformer.fetchAdaptedBases();
	if (adaptedBases == null \|\| adaptedBases.isEmpty()) return;
	List<AspectBinding> aspectBindings = aspectBindingRegistry.getAspectBindings(aspectBundle);
	if (aspectBindings != null)
	for (AspectBinding aspectBinding : aspectBindings)
	if (!aspectBinding.hasScannedTeams)
	for (TeamBinding team : aspectBinding.teams)
	if (team.teamName.equals(className))
	if (!team.hasScannedBases) {
	for (TeamBinding equivalent : team.equivalenceSet) {
	equivalent.addBaseClassNames(adaptedBases);
	equivalent.hasScannedBases = true;
	}
	return; // done all equivalent teams
	}
	}

	// ===== handling deferred teams: ======

	/**
	* Record the given team classes as waiting for instantiation/activation.
	* Callback during {@link BaseBundleLoadTrigger#fire()}
	*/
	public void addDeferredTeamClasses(List<WaitingTeamRecord> teamClasses) {
	synchronized (deferredTeams) {
	deferredTeams.addAll(teamClasses);
	}
	}

	/**
	* Try to instantiate/activate any deferred teams that may be unblocked
	* by the definition of the given trigger class.
	*/
	public void instantiateScheduledTeams(String triggerClassName) {
	List<WaitingTeamRecord> scheduledTeams = null;
	synchronized(deferredTeams) {
	for (WaitingTeamRecord record : new ArrayList<>(deferredTeams)) {
	if (record.notFoundClass.equals(triggerClassName)) {
	if (scheduledTeams == null)
	scheduledTeams = new ArrayList<>();
	if (deferredTeams.remove(record))
	scheduledTeams.add(record);
	}
	}
	}
	if (scheduledTeams == null) return;
	for(WaitingTeamRecord record : scheduledTeams) {
	if (record.team.isActivated)
	continue;
	String teamName = record.team.teamName;
	log(IStatus.INFO, "Consider for instantiation/activation: team "+teamName);
	try {
	TeamLoader loader = new TeamLoader(deferredTeams, beingDefined, this.useDynamicWeaver);
	// Instantiate (we only get here if activationKind != NONE)
	loader.instantiateAndActivate(record.aspectBinding, record.team, record.activationKind); // may re-insert to deferredTeams
	} catch (Exception e) {
	log(e, "Failed to instantiate team "+teamName);
	continue;
	}
	}
	}

	@Override
	public void modified(WovenClass wovenClass) {
	if (wovenClass.getState() == WovenClass.DEFINED) {
	@NonNull String className = wovenClass.getClassName();
	if (className.equals(ORG_OBJECTTEAMS_TEAM)) {
	this.ooTeam = wovenClass.getDefinedClass();
	installLiftingParticipant();
	}
	beingDefined.remove(className);
	instantiateScheduledTeams(className);

	TransformerPlugin.flushLog();
	}
	}

	static boolean hasImport(WovenClass clazz, String packageName, String packageWithAttribute) {
	List<String> imports = clazz.getDynamicImports();
	for (String imp : imports)
	if (imp.equals(packageName) \|\| imp.equals(packageWithAttribute))
	return true;
	for (Wire wire : clazz.getBundleWiring().getRequiredResourceWires(PackageNamespace.PACKAGE_NAMESPACE)) {
	Object packageValue = wire.getRequirement().getAttributes().get(PackageNamespace.PACKAGE_NAMESPACE);
	if (packageName.equals(packageValue) \|\| packageWithAttribute.equals(packageValue))
	return true;
	}
	return false;

	}

	private boolean needsThreadNotificationCode(String className, byte[] bytes, ClassLoader resourceLoader) {

	if ("java.lang.Object".equals(className))
	return false; // shortcut, have no super
	ClassInformation classInfo = null;
	if (bytes != null) {
	classInfo = this.byteCodeAnalyzer.getClassInformation(bytes, className);
	} else {
	try (InputStream is = resourceLoader.getResourceAsStream(className.replace('.', '/')+".class")) {
	if (is != null) {
	classInfo = this.byteCodeAnalyzer.getClassInformation(is, className);
	}
	} catch (IOException e) {
	return false;
	}
	}
	if (classInfo != null && !classInfo.isInterface()) {
	String superClassName = classInfo.getSuperClassName();
	if ("java.lang.Thread".equals(superClassName))
	return true; // ensure TeamActivation will weave the calls to TeamThreadManager
	String[] superInterfaceNames = classInfo.getSuperInterfaceNames();
	if (superInterfaceNames != null)
	for (int i = 0; i < superInterfaceNames.length; i++) {
	if ("java.lang.Runnable".equals(superInterfaceNames[i]))
	return true; // ensure TeamActivation will weave the calls to TeamThreadManager
	}
	}
	return false;
	}

	}