Copyright (c) 2005, 2014 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) 2005, 2014 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.core.internal.registry.osgi;

import java.io.File;
import java.util.Hashtable;
import org.eclipse.core.internal.adapter.AdapterManagerListener;
import org.eclipse.core.internal.registry.*;
import org.eclipse.core.runtime.*;
import org.eclipse.core.runtime.spi.RegistryStrategy;
import org.eclipse.osgi.service.datalocation.Location;
import org.osgi.framework.*;

The extension registry bundle. This activator will create the default OSGi registry
unless told otherwise by setting the following system property to false:
eclipse.createRegistry=false
The default registry will be stopped on the bundle shutdown.
See Also:
PROP_DEFAULT_REGISTRY.PROP_DEFAULT_REGISTRY/**
 * The extension registry bundle. This activator will create the default OSGi registry
 * unless told otherwise by setting the following system property to false:
 * <code>eclipse.createRegistry=false</code>
 *
 * The default registry will be stopped on the bundle shutdown.
 *
 * @see IRegistryConstants#PROP_DEFAULT_REGISTRY
 */
public class Activator implements BundleActivator {

	private static BundleContext bundleContext;

	
Location of the default registry relative to the configuration area
/**
	 * Location of the default registry relative to the configuration area
	 */
	private static final String STORAGE_DIR = "org.eclipse.core.runtime"; //$NON-NLS-1$

	private Object masterRegistryKey = new Object();
	private Object userRegistryKey = new Object();

	private IExtensionRegistry defaultRegistry = null;
	private ServiceRegistration<?> registryRegistration;
	private ServiceRegistration<?> commandRegistration;
	private RegistryProviderOSGI defaultProvider;
	private AdapterManagerListener adapterManagerListener = null;

	
This method is called upon plug-in activation
/**
	 * This method is called upon plug-in activation
	 */
	@Override
	public void start(BundleContext context) throws Exception {
		bundleContext = context;
		RegistryProperties.setContext(bundleContext);
		processCommandLine();
		startRegistry();
		adapterManagerListener = new AdapterManagerListener(); // after extension registry
	}

	
This method is called when the plug-in is stopped
/**
	 * This method is called when the plug-in is stopped
	 */
	@Override
	public void stop(BundleContext context) throws Exception {
		if (adapterManagerListener != null)
			adapterManagerListener.stop(); // before extension registry
		stopRegistry();
		RegistryProperties.setContext(null);
		bundleContext = null;
	}

	public static BundleContext getContext() {
		return bundleContext;
	}

	
Look for the no registry cache flag and check to see if we should NOT be lazily loading plug-in
definitions from the registry cache file.
NOTE: this command line processing is only performed in the presence of OSGi
/**
	 * Look for the no registry cache flag and check to see if we should NOT be lazily loading plug-in
	 * definitions from the registry cache file.
	 * NOTE: this command line processing is only performed in the presence of OSGi
	 */
	private void processCommandLine() {
		// use a string here instead of the class to prevent class loading.
		ServiceReference<?> ref = getContext().getServiceReference("org.eclipse.osgi.service.environment.EnvironmentInfo"); //$NON-NLS-1$
		if (ref == null)
			return;
		String[] args = EquinoxUtils.getCommandLine(bundleContext, ref);
		if (args == null || args.length == 0)
			return;
		for (String arg : args) {
			if (arg.equalsIgnoreCase(IRegistryConstants.NO_REGISTRY_CACHE)) {
				RegistryProperties.setProperty(IRegistryConstants.PROP_NO_REGISTRY_CACHE, "true"); //$NON-NLS-1$
			} else if (arg.equalsIgnoreCase(IRegistryConstants.NO_LAZY_REGISTRY_CACHE_LOADING)) {
				RegistryProperties.setProperty(IRegistryConstants.PROP_NO_LAZY_CACHE_LOADING, "true"); //$NON-NLS-1$
			} else if (arg.equalsIgnoreCase(IRegistryConstants.MULTI_LANGUAGE)) {
				RegistryProperties.setProperty(IRegistryConstants.PROP_MULTI_LANGUAGE, "true"); //$NON-NLS-1$
			}
		}
	}

	public void startRegistry() throws CoreException {
		// see if the customer suppressed the creation of default registry
		String property = bundleContext.getProperty(IRegistryConstants.PROP_DEFAULT_REGISTRY);
		if (property != null && property.equalsIgnoreCase("false")) //$NON-NLS-1$
			return;

		// check to see if we need to use null as a userToken
		if ("true".equals(bundleContext.getProperty(IRegistryConstants.PROP_REGISTRY_NULL_USER_TOKEN))) //$NON-NLS-1$
			userRegistryKey = null;

		// Determine primary and alternative registry locations. Eclipse extension registry cache
		// can be found in one of the two locations:
		// a) in the local configuration area (standard location passed in by the platform) -> priority
		// b) in the shared configuration area (typically, shared install is used)
		File[] registryLocations;
		boolean[] readOnlyLocations;

		RegistryStrategy strategy = null;
		Location configuration = OSGIUtils.getDefault().getConfigurationLocation();
		if (configuration == null) {
			RegistryProperties.setProperty(IRegistryConstants.PROP_NO_REGISTRY_CACHE, "true"); //$NON-NLS-1$
			RegistryProperties.setProperty(IRegistryConstants.PROP_NO_LAZY_CACHE_LOADING, "true"); //$NON-NLS-1$
			strategy = new RegistryStrategyOSGI(null, null, masterRegistryKey);
		} else {
			File primaryDir = new File(configuration.getURL().getPath() + '/' + STORAGE_DIR);
			boolean primaryReadOnly = configuration.isReadOnly();

			Location parentLocation = configuration.getParentLocation();
			if (parentLocation != null) {
				File secondaryDir = new File(parentLocation.getURL().getFile() + '/' + IRegistryConstants.RUNTIME_NAME);
				registryLocations = new File[] {primaryDir, secondaryDir};
				readOnlyLocations = new boolean[] {primaryReadOnly, true}; // secondary Eclipse location is always read only
			} else {
				registryLocations = new File[] {primaryDir};
				readOnlyLocations = new boolean[] {primaryReadOnly};
			}
			strategy = new EquinoxRegistryStrategy(registryLocations, readOnlyLocations, masterRegistryKey);
		}

		defaultRegistry = RegistryFactory.createRegistry(strategy, masterRegistryKey, userRegistryKey);

		registryRegistration = Activator.getContext().registerService(IExtensionRegistry.class.getName(), defaultRegistry, new Hashtable<String, Object>());
		defaultProvider = new RegistryProviderOSGI(defaultRegistry);
		// Set the registry provider and specify this as a default registry:
		RegistryProviderFactory.setDefault(defaultProvider);
		commandRegistration = EquinoxUtils.registerCommandProvider(Activator.getContext());
	}

	private void stopRegistry() {
		if (defaultRegistry != null) {
			RegistryProviderFactory.releaseDefault();
			registryRegistration.unregister();
			defaultRegistry.stop(masterRegistryKey);
		}
		if (commandRegistration != null)
			commandRegistration.unregister();
	}

}