Fixes #671 - Move some platform-ui undo utility classes into a core location

resources/bundles/org.eclipse.core.resources/META-INF/MANIFEST.MF

@@ -2,7 +2,7 @@ Manifest-Version: 1.0
 Bundle-ManifestVersion: 2
 Bundle-Name: %pluginName
 Bundle-SymbolicName: org.eclipse.core.resources; singleton:=true
-Bundle-Version: 3.19.200.qualifier
+Bundle-Version: 3.20.0.qualifier
 Bundle-Activator: org.eclipse.core.resources.ResourcesPlugin
 Bundle-Vendor: %providerName
 Bundle-Localization: plugin
@@ -23,6 +23,7 @@ Export-Package: org.eclipse.core.internal.dtree;x-internal:=true,
  org.eclipse.core.resources.mapping,
  org.eclipse.core.resources.refresh,
  org.eclipse.core.resources.team,
+ org.eclipse.core.resources.undo.snapshot,
  org.eclipse.core.resources.variableresolvers
 Require-Bundle: org.eclipse.ant.core;bundle-version="[3.1.0,4.0.0)";resolution:=optional,
  org.eclipse.core.expressions;bundle-version="[3.2.0,4.0.0)",

resources/bundles/org.eclipse.core.resources/src/org/eclipse/core/internal/resources/undo/snapshot/AbstractResourceSnapshot.java

@@ -0,0 +1,141 @@
+/*******************************************************************************
+ * Copyright (c) 2006, 2023 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
+ *     Red Hat Inc - Adapted from classes in org.eclipse.ui.ide.undo and org.eclipse.ui.internal.ide.undo
+ *******************************************************************************/
+
+package org.eclipse.core.internal.resources.undo.snapshot;
+
+import org.eclipse.core.resources.IContainer;
+import org.eclipse.core.resources.IMarker;
+import org.eclipse.core.resources.IResource;
+import org.eclipse.core.resources.IWorkspace;
+import org.eclipse.core.resources.ResourceAttributes;
+import org.eclipse.core.resources.ResourcesPlugin;
+import org.eclipse.core.resources.undo.snapshot.IResourceSnapshot;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IProgressMonitor;
+
+/**
+ * Base implementation of ResourceSnapshot that describes the common attributes
+ * of a resource to be created.
+ *
+ * This class is not intended to be instantiated or used by clients.
+ *
+ * @since 3.20
+ *
+ */
+abstract class AbstractResourceSnapshot implements IResourceSnapshot {
+	IContainer parent;
+
+	long modificationStamp = IResource.NULL_STAMP;
+
+	long localTimeStamp = IResource.NULL_STAMP;
+
+	ResourceAttributes resourceAttributes;
+
+	MarkerSnapshot[] markerDescriptions;
+
+	/**
+	 * Create a resource snapshot with no initial attributes
+	 */
+	protected AbstractResourceSnapshot() {
+		super();
+	}
+
+	/**
+	 * Create a resource snapshot from the specified resource.
+	 *
+	 * @param resource the resource to be described
+	 */
+	protected AbstractResourceSnapshot(IResource resource) {
+		super();
+		parent = resource.getParent();
+		if (resource.isAccessible()) {
+			modificationStamp = resource.getModificationStamp();
+			localTimeStamp = resource.getLocalTimeStamp();
+			resourceAttributes = resource.getResourceAttributes();
+			try {
+				IMarker[] markers = resource.findMarkers(null, true,
+						IResource.DEPTH_INFINITE);
+				markerDescriptions = new MarkerSnapshot[markers.length];
+				for (int i = 0; i < markers.length; i++) {
+					markerDescriptions[i] = new MarkerSnapshot(markers[i]);
+				}
+			} catch (CoreException e) {
+				// Eat this exception because it only occurs when the resource
+				// does not exist and we have already checked this.
+				// We do not want to throw exceptions on the simple constructor,
+				// as no one has actually tried to do anything yet.
+			}
+		}
+	}
+
+	@Override
+	public IResource createResource(IProgressMonitor monitor)
+			throws CoreException {
+		IResource resource = createResourceHandle();
+		createExistentResourceFromHandle(resource, monitor);
+		restoreResourceAttributes(resource);
+		return resource;
+	}
+
+	@Override
+	public boolean isValid() {
+		return parent == null || parent.exists();
+	}
+
+	/**
+	 * Restore any saved attributed of the specified resource. This method is
+	 * called after the existent resource represented by the receiver has been
+	 * created.
+	 *
+	 * @param resource
+	 *            the newly created resource
+	 * @throws CoreException
+	 */
+	protected void restoreResourceAttributes(IResource resource)
+			throws CoreException {
+		if (modificationStamp != IResource.NULL_STAMP) {
+			resource.revertModificationStamp(modificationStamp);
+		}
+		if (localTimeStamp != IResource.NULL_STAMP) {
+			resource.setLocalTimeStamp(localTimeStamp);
+		}
+		if (resourceAttributes != null) {
+			resource.setResourceAttributes(resourceAttributes);
+		}
+		if (markerDescriptions != null) {
+			for (MarkerSnapshot markerDescription : markerDescriptions) {
+				if (markerDescription.resource.exists())
+					markerDescription.createMarker();
+			}
+		}
+	}
+
+	/*
+	 * Return the workspace.
+	 */
+	IWorkspace getWorkspace() {
+		return ResourcesPlugin.getWorkspace();
+	}
+
+	@Override
+	public boolean verifyExistence(boolean checkMembers) {
+		IContainer p = parent;
+		if (p == null) {
+			p = getWorkspace().getRoot();
+		}
+		IResource handle = p.findMember(getName());
+		return handle != null;
+	}
+}