Copyright (c) 2008, 2013 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) 2008, 2013 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.internal.permadmin;

import java.security.*;
import java.util.Enumeration;
import java.util.NoSuchElementException;
import org.osgi.framework.Bundle;
import org.osgi.framework.PackagePermission;

public final class BundlePermissions extends PermissionCollection {
	private static final long serialVersionUID = -5443618108312606612L;

	// Note that this forces the Enumeration inner class to be loaded as soon as possible (see bug 119069)  
	static final Enumeration<Permission> EMPTY_ENUMERATION = new Enumeration<Permission>() {
		@Override
		public boolean hasMoreElements() {
			return false;
		}

		@Override
		public Permission nextElement() {
			throw new NoSuchElementException();
		}
	};

	private final Bundle bundle;
	private final SecurityAdmin securityAdmin;
	private final PermissionInfoCollection impliedPermissions;
	private final PermissionInfoCollection restrictedPermissions;
	private final Permissions wovenPermissions;

	public BundlePermissions(Bundle bundle, SecurityAdmin securityAdmin, PermissionInfoCollection impliedPermissions, PermissionInfoCollection restrictedPermissions) {
		this.bundle = bundle;
		this.securityAdmin = securityAdmin;
		this.impliedPermissions = impliedPermissions;
		this.restrictedPermissions = restrictedPermissions;
		this.wovenPermissions = new Permissions();
		setReadOnly(); // collections are managed with ConditionalPermissionAdmin
	}

	@Override
	public void add(Permission permission) {
		throw new SecurityException();
	}

	
Add a package permission to this woven bundle.

Bundles may require additional permissions in order to execute byte code
woven by weaving hooks.
Params:
permission – The package permission to add to this woven bundle.
Throws:
SecurityException – If the permission does not have an action of PackagePermission.IMPORT./**
	 * Add a package permission to this woven bundle.
	 * <p/>
	 * Bundles may require additional permissions in order to execute byte code
	 * woven by weaving hooks.
	 * 
	 * @param permission The package permission to add to this woven bundle.
	 * @throws SecurityException If the <code>permission</code>
	 *         does not have an action of {@link PackagePermission#IMPORT}.
	 */
	public void addWovenPermission(PackagePermission permission) {
		if (!permission.getActions().equals(PackagePermission.IMPORT))
			throw new SecurityException();
		wovenPermissions.add(permission);
	}

	@Override
	public Enumeration<Permission> elements() {
		// TODO return an empty enumeration for now; 
		// It does not seem possible to do this properly with multiple exports and conditional permissions.
		// When looking to fix this be sure the Enumeration class is loaded as soon as possible (see bug 119069)
		return EMPTY_ENUMERATION;
	}

	@Override
	public boolean implies(Permission permission) {
		// first check implied permissions
		if ((impliedPermissions != null) && impliedPermissions.implies(permission))
			return true;

		// Now check implied permissions added by weaving hooks.
		if (wovenPermissions.implies(permission))
			return true;

		// We must be allowed by the restricted permissions to have any hope of passing the check
		if ((restrictedPermissions != null) && !restrictedPermissions.implies(permission))
			return false;

		return securityAdmin.checkPermission(permission, this);
	}

	public Bundle getBundle() {
		return bundle;
	}

	public void clearPermissionCache() {
		if (impliedPermissions != null)
			impliedPermissions.clearPermissionCache();
		if (restrictedPermissions != null)
			restrictedPermissions.clearPermissionCache();
	}
}