/*
* Copyright (c) 2011 Google Inc.
*
* 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 com.google.eclipse.protobuf.ui.util.editor;
import static org.eclipse.compare.rangedifferencer.RangeDifferencer.findDifferences;
import static org.eclipse.core.filebuffers.FileBuffers.createTextFileBufferManager;
import static org.eclipse.core.runtime.Status.OK_STATUS;
import static org.eclipse.core.runtime.SubProgressMonitor.PREPEND_MAIN_LABEL_TO_SUBTASK;
import static com.google.common.collect.Lists.newArrayList;
import static com.google.eclipse.protobuf.ui.util.IStatusFactory.error;
import static com.google.eclipse.protobuf.ui.util.editor.Messages.calculatingChangedRegions;
import static com.google.eclipse.protobuf.ui.util.editor.Messages.errorCalculatingChangedRegions;
import java.util.List;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.log4j.Logger;
import org.eclipse.compare.rangedifferencer.RangeDifference;
import org.eclipse.core.filebuffers.ITextFileBuffer;
import org.eclipse.core.filebuffers.ITextFileBufferManager;
import org.eclipse.core.filesystem.IFileStore;
import org.eclipse.core.runtime.CoreException;
import org.eclipse.core.runtime.IProgressMonitor;
import org.eclipse.core.runtime.ISafeRunnable;
import org.eclipse.core.runtime.IStatus;
import org.eclipse.core.runtime.NullProgressMonitor;
import org.eclipse.core.runtime.SafeRunner;
import org.eclipse.core.runtime.SubProgressMonitor;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.jface.text.Region;
import com.google.inject.Singleton;
/**
* Utility methods related to editors. Adapted from CDT's
* {@code org.eclipse.cdt.internal.ui.util.EditorUtility}.
*
* @author alruiz@google.com (Alex Ruiz)
*/
@Singleton public class ChangedLineRegionCalculator {
private static Logger logger = Logger.getLogger(ChangedLineRegionCalculator.class);
public IRegion[] calculateChangedLineRegions(final ITextFileBuffer buffer, final IDocument current,
final IProgressMonitor monitor) throws CoreException {
final AtomicReference<IRegion[]> result = new AtomicReference<IRegion[]>();
final AtomicReference<IStatus> errorStatus = new AtomicReference<IStatus>(OK_STATUS);
try {
SafeRunner.run(new ISafeRunnable() {
@Override public void handleException(Throwable exception) {
logger.error(exception.getMessage(), exception);
errorStatus.set(error(errorCalculatingChangedRegions, exception));
result.set(null);
}
@Override public void run() throws Exception {
monitor.beginTask(calculatingChangedRegions, 20);
IFileStore fileStore = buffer.getFileStore();
ITextFileBufferManager fileBufferManager = createTextFileBufferManager();
fileBufferManager.connectFileStore(fileStore, getSubProgressMonitor(monitor, 15));
try {
IDocument old = ((ITextFileBuffer) fileBufferManager.getFileStoreFileBuffer(fileStore)).getDocument();
result.set(getChangedLineRegions(old));
} finally {
fileBufferManager.disconnectFileStore(fileStore, getSubProgressMonitor(monitor, 5));
monitor.done();
}
}
/*
* Returns regions of all lines which differ comparing {@code old}s content with {@code current}s content.
* Successive lines are merged into one region.
*/
private IRegion[] getChangedLineRegions(IDocument old) {
RangeDifference[] differences = differencesWith(old);
List<IRegion> regions = newArrayList();
int numberOfLines = current.getNumberOfLines();
for (RangeDifference difference : differences) {
if (difference.kind() == RangeDifference.CHANGE) {
int startLine = Math.min(difference.rightStart(), numberOfLines - 1);
int endLine = difference.rightEnd() - 1;
IRegion startLineRegion;
try {
startLineRegion = current.getLineInformation(startLine);
if (startLine >= endLine) {
// startLine > endLine indicates a deletion of one or more lines.
// Deletions are ignored except at the end of the document.
if (startLine == endLine
|| startLineRegion.getOffset() + startLineRegion.getLength() == current.getLength()) {
regions.add(startLineRegion);
}
continue;
}
IRegion endLineRegion = current.getLineInformation(endLine);
int startOffset = startLineRegion.getOffset();
int endOffset = endLineRegion.getOffset() + endLineRegion.getLength();
regions.add(new Region(startOffset, endOffset - startOffset));
} catch (BadLocationException e) {
logger.error(e.getMessage(), e);
}
}
}
return regions.toArray(new IRegion[regions.size()]);
}
private RangeDifference[] differencesWith(IDocument old) {
return findDifferences(new LineComparator(old), new LineComparator(current));
}
});
} finally {
IStatus status = errorStatus.get();
if (!status.isOK()) {
throw new CoreException(status);
}
}
return result.get();
}
private static IProgressMonitor getSubProgressMonitor(IProgressMonitor monitor, int ticks) {
if (monitor != null) {
return new SubProgressMonitor(monitor, ticks, PREPEND_MAIN_LABEL_TO_SUBTASK);
}
return new NullProgressMonitor();
}
}