Copyright (c) 2013, 2017 IBM Corporation and others.
This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
which accompanies this distribution, and is available at
https://www.eclipse.org/legal/epl-2.0/
SPDX-License-Identifier: EPL-2.0
Contributors:
    IBM Corporation - initial API and implementation
/*******************************************************************************
 * Copyright (c) 2013, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.osgi.storage;

import java.io.File;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.net.MalformedURLException;
import java.net.URL;
import java.security.AccessController;
import java.security.PrivilegedActionException;
import java.security.PrivilegedExceptionAction;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.List;
import org.eclipse.osgi.container.Module;
import org.eclipse.osgi.container.ModuleCapability;
import org.eclipse.osgi.container.ModuleRevision;
import org.eclipse.osgi.container.ModuleWire;
import org.eclipse.osgi.container.ModuleWiring;
import org.eclipse.osgi.container.namespaces.EquinoxModuleDataNamespace;
import org.eclipse.osgi.framework.util.ArrayMap;
import org.eclipse.osgi.internal.framework.EquinoxConfiguration;
import org.eclipse.osgi.internal.hookregistry.ActivatorHookFactory;
import org.eclipse.osgi.internal.hookregistry.HookRegistry;
import org.eclipse.osgi.internal.messages.Msg;
import org.eclipse.osgi.internal.url.MultiplexingFactory;
import org.eclipse.osgi.storage.BundleInfo.Generation;
import org.eclipse.osgi.util.NLS;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.BundleException;
import org.osgi.framework.FrameworkEvent;
import org.osgi.framework.namespace.HostNamespace;
import org.osgi.framework.wiring.BundleWiring;
import org.osgi.resource.Capability;

public class FrameworkExtensionInstaller {
	private static final ClassLoader CL = FrameworkExtensionInstaller.class.getClassLoader();
	private static final Method ADD_FWK_URL_METHOD = findAddURLMethod(CL, "addURL"); //$NON-NLS-1$
	private static final Method ADD_FWK_FILE_PATH_METHOD = ADD_FWK_URL_METHOD == null ? findAddFilePathMethod(CL, "appendToClassPathForInstrumentation") : null; //$NON-NLS-1$
	private final ArrayMap<BundleActivator, Bundle> hookActivators = new ArrayMap<>(5);

	private static Method findAddURLMethod(ClassLoader cl, String name) {
		if (cl == null)
			return null;
		return findMethod(cl.getClass(), name, new Class[] {URL.class}, null);
	}

	private static Method findAddFilePathMethod(ClassLoader cl, String name) {
		if (cl == null)
			return null;
		return findMethod(cl.getClass(), name, new Class[] {String.class}, MultiplexingFactory.setAccessible);
	}

	// recursively searches a class and it's superclasses for a (potentially inaccessable) method
	private static Method findMethod(Class<?> clazz, String name, Class<?>[] args, Collection<AccessibleObject> setAccessible) {
		if (clazz == null)
			return null; // ends the recursion when getSuperClass returns null
		try {
			Method result = clazz.getDeclaredMethod(name, args);
			if (setAccessible != null) {
				setAccessible.add(result);
			} else {
				result.setAccessible(true);
			}
			return result;
		} catch (SecurityException e) {
			// if we do not have the permissions then we will not find the method
		} catch (NoSuchMethodException | RuntimeException e) {
			// do nothing look in super class below
			// have to avoid blowing up <clinit>
		}
		return findMethod(clazz.getSuperclass(), name, args, setAccessible);
	}

	private static void callAddURLMethod(URL arg) throws InvocationTargetException {
		try {
			ADD_FWK_URL_METHOD.invoke(CL, new Object[] {arg});
		} catch (Throwable t) {
			throw new InvocationTargetException(t);
		}
	}

	private static void callAddFilePathMethod(File file) throws InvocationTargetException {
		try {
			ADD_FWK_FILE_PATH_METHOD.invoke(CL, new Object[] {file.getCanonicalPath()});
		} catch (Throwable t) {
			throw new InvocationTargetException(t);
		}
	}

	private final EquinoxConfiguration configuration;

	public FrameworkExtensionInstaller(EquinoxConfiguration configuraiton) {
		this.configuration = configuraiton;
	}

	public void addExtensionContent(final Collection<ModuleRevision> revisions, final Module systemModule) throws BundleException {
		if (System.getSecurityManager() == null) {
			addExtensionContent0(revisions, systemModule);
		} else {
			try {
				AccessController.doPrivileged(new PrivilegedExceptionAction<Void>() {
					@Override
					public Void run() throws BundleException {
						addExtensionContent0(revisions, systemModule);
						return null;
					}
				});
			} catch (PrivilegedActionException e) {
				throw (BundleException) e.getCause();
			}
		}
	}

	void addExtensionContent0(Collection<ModuleRevision> revisions, Module systemModule) throws BundleException {
		if (revisions.isEmpty()) {
			// NOTE: revisions could be empty when initializing the framework with no
			// framework extensions
			return;
		}

		for (ModuleRevision revision : revisions) {
			if (CL == null || (ADD_FWK_URL_METHOD == null && ADD_FWK_FILE_PATH_METHOD == null)) {
				// use the first revision as the blame
				throw new BundleException("Cannot support framework extension bundles without a public addURL(URL) or appendToClassPathForInstrumentation(String) method on the framework class loader: " + revision.getBundle()); //$NON-NLS-1$
			}
			File[] files = getExtensionFiles(revision);
			for (File file : files) {
				if (file == null) {
					continue;
				}
				try {
					if (ADD_FWK_URL_METHOD != null) {
						callAddURLMethod(StorageUtil.encodeFileURL(file));
					} else if (ADD_FWK_FILE_PATH_METHOD != null) {
						callAddFilePathMethod(file);
					}
				} catch (InvocationTargetException | MalformedURLException e) {
					throw new BundleException("Error adding extension content.", e); //$NON-NLS-1$
				}
			}
		}

		if (CL != null) {
			try {
				// initialize the new urls
				CL.loadClass("thisIsNotAClass"); //$NON-NLS-1$
			} catch (ClassNotFoundException e) {
				// do nothing
			}
		}
		if (systemModule != null) {
			BundleContext systemContext = systemModule.getBundle().getBundleContext();
			for (ModuleRevision revision : revisions) {
				if (systemContext != null) {
					startExtensionActivator(revision, systemContext);
				}
			}
		}
	}

	
Returns a list of classpath files for an extension bundle
Params:
revision – revision for the extension bundle
Returns:
a list of classpath files for an extension bundle/**
	 * Returns a list of classpath files for an extension bundle
	 * @param revision revision for the extension bundle
	 * @return a list of classpath files for an extension bundle
	 */
	private File[] getExtensionFiles(ModuleRevision revision) {
		List<ModuleCapability> metaDatas = revision.getModuleCapabilities(EquinoxModuleDataNamespace.MODULE_DATA_NAMESPACE);
		@SuppressWarnings("unchecked")
		List<String> paths = metaDatas.isEmpty() ? null : (List<String>) metaDatas.get(0).getAttributes().get(EquinoxModuleDataNamespace.CAPABILITY_CLASSPATH);
		if (paths == null) {
			paths = new ArrayList<>(1);
			paths.add("."); //$NON-NLS-1$
		}
		if (configuration.inDevelopmentMode()) {
			// must create a copy because paths could be unmodifiable
			paths = new ArrayList<>(paths);
			String[] devPaths = configuration.getDevClassPath(revision.getSymbolicName());
			Collections.addAll(paths, devPaths);
		}
		List<File> results = new ArrayList<>(paths.size());
		for (String path : paths) {
			if (".".equals(path)) { //$NON-NLS-1$
				results.add(((Generation) revision.getRevisionInfo()).getBundleFile().getBaseFile());
			} else {
				File result = ((Generation) revision.getRevisionInfo()).getBundleFile().getFile(path, false);
				if (result != null)
					results.add(result);
			}
		}
		return results.toArray(new File[results.size()]);
	}

	public void startExtensionActivators(BundleContext context) {
		// First start the hook registry activators
		// TODO not sure we really need these anymore
		HookRegistry hookRegistry = configuration.getHookRegistry();
		List<ActivatorHookFactory> activatorHookFactories = hookRegistry.getActivatorHookFactories();
		for (ActivatorHookFactory activatorFactory : activatorHookFactories) {
			BundleActivator activator = activatorFactory.createActivator();
			try {
				startActivator(activator, context, null);
			} catch (Exception e) {
				configuration.getHookRegistry().getContainer().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, null, e);
			}
		}
		// start the extension bundle activators.  In Equinox we let
		// framework extensions define Bundle-Activator headers.
		ModuleWiring systemWiring = (ModuleWiring) context.getBundle().adapt(BundleWiring.class);
		if (systemWiring != null) {
			List<ModuleWire> extensionWires = systemWiring.getProvidedModuleWires(HostNamespace.HOST_NAMESPACE);
			for (ModuleWire extensionWire : extensionWires) {
				ModuleRevision extensionRevision = extensionWire.getRequirer();
				startExtensionActivator(extensionRevision, context);
			}
		}
	}

	public void stopExtensionActivators(BundleContext context) {
		ArrayMap<BundleActivator, Bundle> current;
		synchronized (hookActivators) {
			current = new ArrayMap<>(hookActivators.getKeys(), hookActivators.getValues());
			hookActivators.clear();
		}
		for (BundleActivator activator : current) {
			try {
				activator.stop(context);
			} catch (Exception e) {
				Bundle b = current.get(activator);
				BundleException eventException = new BundleException(NLS.bind(Msg.BUNDLE_ACTIVATOR_EXCEPTION, new Object[] {activator.getClass(), "stop", b == null ? "" : b.getSymbolicName()}), BundleException.ACTIVATOR_ERROR, e); //$NON-NLS-1$ //$NON-NLS-2$
				configuration.getHookRegistry().getContainer().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, b, eventException);
			}
		}
	}

	private void startExtensionActivator(ModuleRevision extensionRevision, BundleContext context) {
		List<Capability> metadata = extensionRevision.getCapabilities(EquinoxModuleDataNamespace.MODULE_DATA_NAMESPACE);
		if (metadata.isEmpty()) {
			return;
		}

		String activatorName = (String) metadata.get(0).getAttributes().get(EquinoxModuleDataNamespace.CAPABILITY_ACTIVATOR);
		if (activatorName == null) {
			return;
		}

		BundleActivator activator = null;
		try {
			Class<?> activatorClass = Class.forName(activatorName);
			activator = (BundleActivator) activatorClass.getConstructor().newInstance();
			startActivator(activator, context, extensionRevision.getBundle());
		} catch (Throwable e) {
			BundleException eventException;
			if (activator == null) {
				eventException = new BundleException(Msg.BundleContextImpl_LoadActivatorError, BundleException.ACTIVATOR_ERROR, e);
			} else {
				eventException = new BundleException(NLS.bind(Msg.BUNDLE_ACTIVATOR_EXCEPTION, new Object[] {activator.getClass(), "start", extensionRevision.getSymbolicName()}), BundleException.ACTIVATOR_ERROR, e); //$NON-NLS-1$
			}
			configuration.getHookRegistry().getContainer().getEventPublisher().publishFrameworkEvent(FrameworkEvent.ERROR, extensionRevision.getBundle(), eventException);
		}

	}

	private void startActivator(BundleActivator activator, BundleContext context, Bundle b) throws Exception {
		activator.start(context);
		synchronized (hookActivators) {
			hookActivators.put(activator, b);
		}
	}

}