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/*******************************************************************************
* 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
*/
public final class RewriteSessionEditProcessor extends TextEditProcessor {
/** The threshold for large text edits. */
private static final int THRESHOLD= 1000;
/**
* 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.
*
* @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.
*
* @param edit the edit to check
* @return true
if edit
is considered large,
* false
otherwise
* @since 3.3
*/
public static boolean isLargeEdit(TextEdit edit) {
SizeVisitor sizeVisitor= new SizeVisitor();
edit.accept(sizeVisitor);
return sizeVisitor.fSize > THRESHOLD;
}
}