core/plugins/org.eclipse.dltk.core/model/org/eclipse/dltk/internal/core/DiscardWorkingCopyOperation.java

/*******************************************************************************
 * Copyright (c) 2000, 2016 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 *******************************************************************************/
package org.eclipse.dltk.internal.core;

import org.eclipse.core.resources.IResource;
import org.eclipse.dltk.core.IModelElement;
import org.eclipse.dltk.core.IModelElementDelta;
import org.eclipse.dltk.core.IScriptProject;
import org.eclipse.dltk.core.ModelException;

/**
 * Discards a working copy (decrement its use count and remove its working copy
 * info if the use count is 0) and signal its removal through a delta.
 */
public class DiscardWorkingCopyOperation extends ModelOperation {

	public DiscardWorkingCopyOperation(IModelElement workingCopy) {
		super(new IModelElement[] { workingCopy });
	}

	@Override
	protected void executeOperation() throws ModelException {
		SourceModule workingCopy = getWorkingCopy();
		ModelManager manager = ModelManager.getModelManager();
		int useCount = manager.discardPerWorkingCopyInfo(workingCopy);
		if (useCount == 0) {
			IScriptProject scriptProject = workingCopy.getScriptProject();
			if (ExternalScriptProject.EXTERNAL_PROJECT_NAME
					.equals(scriptProject.getElementName())) {
				manager.removePerProjectInfo((ScriptProject) scriptProject);
				manager.containerRemove(scriptProject);
			}
			if (!workingCopy.isPrimary()) {
				// report removedscriptdelta for a non-primary working copy
				ModelElementDelta delta = new ModelElementDelta(
						this.getModel());
				delta.removed(workingCopy);
				addDelta(delta);
				removeReconcileDelta(workingCopy);
			} else {
				IResource resource = workingCopy.getResource();
				if (resource != null && resource.isAccessible()) {
					// report a F_PRIMARY_WORKING_COPY change delta for a
					// primary working copy
					ModelElementDelta delta = new ModelElementDelta(this
							.getModel());
					delta.changed(workingCopy,
							IModelElementDelta.F_PRIMARY_WORKING_COPY);
					addDelta(delta);
				} else {
					// report a REMOVED delta
					ModelElementDelta delta = new ModelElementDelta(this
							.getModel());
					delta.removed(workingCopy,
							IModelElementDelta.F_PRIMARY_WORKING_COPY);
					addDelta(delta);
				}
			}
		}
	}

	/**
	 * Returns the working copy this operation is working on.
	 */
	protected SourceModule getWorkingCopy() {
		return (SourceModule) getElementToProcess();
	}

	@Override
	public boolean isReadOnly() {
		return true;
	}
}