Copyright (c) 2000, 2015 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) 2000, 2015 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.runtime;

import java.io.IOException;
import java.net.URL;
import org.eclipse.core.internal.boot.PlatformURLConnection;
import org.eclipse.core.internal.boot.PlatformURLHandler;
import org.eclipse.osgi.util.NLS;
import org.osgi.framework.Bundle;

Platform URL support
platform:/plugin/pluginId/		maps to pluginDescriptor.getInstallURLInternal()
/**
 * Platform URL support
 * platform:/plugin/pluginId/		maps to pluginDescriptor.getInstallURLInternal()
 */
public class PlatformURLPluginConnection extends PlatformURLConnection {

	private static boolean isRegistered = false;
	public static final String PLUGIN = "plugin"; //$NON-NLS-1$

	/*
	 * Constructor for the class.
	 */
	public PlatformURLPluginConnection(URL url) {
		super(url);
	}

	@Override
	protected boolean allowCaching() {
		return true;
	}

	/*
	 * spec - /plugin/com.example/META-INF/MANIFEST.MF
	 * originalURL - used only for exception messages
	 * result[0] - Bundle (e.g. com.example)
	 * result[1] - String (path) (e.g. META-INF/MANIFEST.MF)
	 */
	public static Object[] parse(String spec, URL originalURL) throws IOException {
		Object[] result = new Object[2];
		if (spec.startsWith("/")) //$NON-NLS-1$
			spec = spec.substring(1);
		if (!spec.startsWith(PLUGIN))
			throw new IOException(NLS.bind(CommonMessages.url_badVariant, originalURL));
		int ix = spec.indexOf('/', PLUGIN.length() + 1); //$NON-NLS-1$
		String ref = ix == -1 ? spec.substring(PLUGIN.length() + 1) : spec.substring(PLUGIN.length() + 1, ix);
		String id = getId(ref);
		Activator activator = Activator.getDefault();
		if (activator == null)
			throw new IOException(CommonMessages.activator_not_available);
		Bundle bundle = activator.getBundle(id);
		if (bundle == null)
			throw new IOException(NLS.bind(CommonMessages.url_resolvePlugin, id));
		result[0] = bundle;
		result[1] = (ix == -1 || (ix + 1) >= spec.length()) ? "/" : spec.substring(ix + 1); //$NON-NLS-1$
		return result;
	}

	@Override
	protected URL resolve() throws IOException {
		String spec = url.getFile().trim();
		Object[] obj = parse(spec, url);
		Bundle b = (Bundle) obj[0];
		String path = (String) obj[1];
		URL result = b.getEntry(path);
		if (result != null || "/".equals(path)) //$NON-NLS-1$
			return result;
		// try resolving the path through the classloader
		result = b.getResource(path);
		if (result != null)
			return result;
		// if the result is null then force the creation of a URL that will throw FileNotFoundExceptions
		return new URL(b.getEntry("/"), path); //$NON-NLS-1$
	}

	public static void startup() {
		// register connection type for platform:/plugin handling
		if (isRegistered)
			return;
		PlatformURLHandler.register(PLUGIN, PlatformURLPluginConnection.class);
		isRegistered = true;
	}
}