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:/fragment/fragmentId/		maps to fragmentDescriptor.getInstallURLInternal()
/**
 * Platform URL support
 * platform:/fragment/fragmentId/		maps to fragmentDescriptor.getInstallURLInternal()
 */
public class PlatformURLFragmentConnection extends PlatformURLConnection {

	private Bundle target = null;
	private static boolean isRegistered = false;
	public static final String FRAGMENT = "fragment"; //$NON-NLS-1$

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

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

	@Override
	protected URL resolve() throws IOException {
		String spec = url.getFile().trim();
		if (spec.startsWith("/")) //$NON-NLS-1$
			spec = spec.substring(1);
		if (!spec.startsWith(FRAGMENT))
			throw new IOException(NLS.bind(CommonMessages.url_badVariant, url));
		int ix = spec.indexOf('/', FRAGMENT.length() + 1); //$NON-NLS-1$
		String ref = ix == -1 ? spec.substring(FRAGMENT.length() + 1) : spec.substring(FRAGMENT.length() + 1, ix);
		String id = getId(ref);
		Activator activator = Activator.getDefault();
		if (activator == null)
			throw new IOException(CommonMessages.activator_not_available);
		target = activator.getBundle(id);
		if (target == null)
			throw new IOException(NLS.bind(CommonMessages.url_resolveFragment, url));
		URL result = target.getEntry("/"); //$NON-NLS-1$
		if (ix == -1 || (ix + 1) >= spec.length())
			return result;
		return new URL(result, spec.substring(ix + 1));
	}

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