Copyright (c) 2006, 2008 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) 2006, 2008 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.jface.text;

import org.eclipse.text.edits.CopyTargetEdit;
import org.eclipse.text.edits.DeleteEdit;
import org.eclipse.text.edits.InsertEdit;
import org.eclipse.text.edits.MalformedTreeException;
import org.eclipse.text.edits.MoveTargetEdit;
import org.eclipse.text.edits.ReplaceEdit;
import org.eclipse.text.edits.TextEdit;
import org.eclipse.text.edits.TextEditProcessor;
import org.eclipse.text.edits.TextEditVisitor;
import org.eclipse.text.edits.UndoEdit;

A text edit processor that brackets the application of edits into a document rewrite session.
Since:
3.3/**
 * A text edit processor that brackets the application of edits into a document rewrite session.
 *
 * @since 3.3
 */
public final class RewriteSessionEditProcessor extends TextEditProcessor {
	
The threshold for large text edits. /** The threshold for <em>large</em> text edits. */
	private static final int THRESHOLD= 1000;

	
Text edit visitor that estimates the compound size of an edit tree in characters.
/**
	 * Text edit visitor that estimates the compound size of an edit tree in characters.
	 */
	private static final class SizeVisitor extends TextEditVisitor {
		int fSize= 0;

		@Override
		public boolean visit(CopyTargetEdit edit) {
			fSize += edit.getLength();
			return super.visit(edit);
		}

		@Override
		public boolean visit(DeleteEdit edit) {
			fSize += edit.getLength();
			return super.visit(edit);
		}

		@Override
		public boolean visit(InsertEdit edit) {
			fSize += edit.getText().length();
			return super.visit(edit);
		}

		@Override
		public boolean visit(MoveTargetEdit edit) {
			fSize += edit.getLength();
			return super.visit(edit);
		}

		@Override
		public boolean visit(ReplaceEdit edit) {
			fSize += Math.max(edit.getLength(), edit.getText().length());
			return super.visit(edit);
		}
	}

	
Constructs a new edit processor for the given document.
Params:
document – the document to manipulate
root – the root of the text edit tree describing the modifications. By passing a text
       edit a a text edit processor the ownership of the edit is transfered to the text edit
       processors. Clients must not modify the edit (e.g adding new children) any longer.
style – TextEdit.NONE, TextEdit.CREATE_UNDO or TextEdit.UPDATE_REGIONS)/**
	 * Constructs a new edit processor for the given document.
	 *
	 * @param document the document to manipulate
	 * @param root the root of the text edit tree describing the modifications. By passing a text
	 *        edit a a text edit processor the ownership of the edit is transfered to the text edit
	 *        processors. Clients must not modify the edit (e.g adding new children) any longer.
	 * @param style {@link TextEdit#NONE}, {@link TextEdit#CREATE_UNDO} or
	 *        {@link TextEdit#UPDATE_REGIONS})
	 */
	public RewriteSessionEditProcessor(IDocument document, TextEdit root, int style) {
		super(document, root, style);
	}

	@Override
	public UndoEdit performEdits() throws MalformedTreeException, BadLocationException {
		IDocument document= getDocument();
		if (!(document instanceof IDocumentExtension4))
			return super.performEdits();

		IDocumentExtension4 extension= (IDocumentExtension4) document;
		boolean isLargeEdit= isLargeEdit(getRoot());
		DocumentRewriteSessionType type= isLargeEdit ? DocumentRewriteSessionType.UNRESTRICTED : DocumentRewriteSessionType.UNRESTRICTED_SMALL;

		DocumentRewriteSession session= extension.startRewriteSession(type);
		try {
			return super.performEdits();
		} finally {
			extension.stopRewriteSession(session);
		}
	}

	
Returns true if the passed edit is considered large,
false otherwise.
Params:
edit – the edit to check
Returns:
true if edit is considered large,
        false otherwise
Since:
3.3/**
	 * Returns <code>true</code> if the passed edit is considered <em>large</em>,
	 * <code>false</code> otherwise.
	 *
	 * @param edit the edit to check
	 * @return <code>true</code> if <code>edit</code> is considered <em>large</em>,
	 *         <code>false</code> otherwise
	 * @since 3.3
	 */
	public static boolean isLargeEdit(TextEdit edit) {
		SizeVisitor sizeVisitor= new SizeVisitor();
		edit.accept(sizeVisitor);
		return sizeVisitor.fSize > THRESHOLD;
	}

}