Copyright (c) 2000, 2010 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, 2010 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.jdt.internal.core;

import org.eclipse.core.resources.ResourcesPlugin;
import org.eclipse.core.runtime.jobs.ISchedulingRule;
import org.eclipse.jdt.core.IJavaElement;
import org.eclipse.jdt.core.JavaModelException;

/*
 * Abstract class for operations that change the classpath
 */
public abstract class ChangeClasspathOperation extends JavaModelOperation {

	protected boolean canChangeResources;

	public ChangeClasspathOperation(IJavaElement[] elements, boolean canChangeResources) {
		super(elements);
		this.canChangeResources = canChangeResources;
	}

	@Override
	protected boolean canModifyRoots() {
		// changing the classpath can modify roots
		return true;
	}

	/*
	 * The resolved classpath of the given project may have changed:
	 * - generate a delta
	 * - trigger indexing
	 * - update project references
	 * - create resolved classpath markers
	 */
	protected void classpathChanged(ClasspathChange change, boolean refreshExternalFolder) throws JavaModelException {
		// reset the project's caches early since some clients rely on the project's caches being up-to-date when run inside an IWorkspaceRunnable
		// (see https://bugs.eclipse.org/bugs/show_bug.cgi?id=212769#c5 )
		JavaProject project = change.project;
		project.resetCaches();

		if (this.canChangeResources) {
			// workaround for https://bugs.eclipse.org/bugs/show_bug.cgi?id=177922
			if (isTopLevelOperation() && !ResourcesPlugin.getWorkspace().isTreeLocked()) {
				new ClasspathValidation(project).validate();
			}

			// delta, indexing and classpath markers are going to be created by the delta processor
			// while handling the resource change (either .classpath change, or project touched)

			project.getProject().clearCachedDynamicReferences();
			// and ensure that external folders are updated as well
			new ExternalFolderChange(project, change.oldResolvedClasspath).updateExternalFoldersIfNecessary(refreshExternalFolder, null);

		} else {
			DeltaProcessingState state = JavaModelManager.getDeltaState();
			JavaElementDelta delta = new JavaElementDelta(getJavaModel());
			int result = change.generateDelta(delta, true/*add classpath change*/);
			if ((result & ClasspathChange.HAS_DELTA) != 0) {
				// create delta
				addDelta(delta);

				// need to recompute root infos
				state.rootsAreStale = true;

				// ensure indexes are updated
				change.requestIndexing();

				// ensure classpath is validated on next build
				state.addClasspathValidation(project);
			}
			if ((result & ClasspathChange.HAS_PROJECT_CHANGE) != 0) {
				// ensure project references are updated on next build
				project.getProject().clearCachedDynamicReferences();
				state.addProjectReferenceChange(project);
			}
			if ((result & ClasspathChange.HAS_LIBRARY_CHANGE) != 0) {
				// ensure external folders are updated on next build
				state.addExternalFolderChange(project, change.oldResolvedClasspath);
			}
		}
	}

	@Override
	protected ISchedulingRule getSchedulingRule() {
		return null; // no lock taken while changing classpath
	}

	@Override
	public boolean isReadOnly() {
		return !this.canChangeResources;
	}

}