/*******************************************************************************
* Copyright (c) 2008-2010 Sonatype, 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
*
* Contributors:
* Sonatype, Inc. - initial API and implementation
*******************************************************************************/
package org.eclipse.m2e.refactoring;
import java.util.ArrayList;
import java.util.Arrays;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.eclipse.compare.rangedifferencer.IRangeComparator;
import org.eclipse.compare.rangedifferencer.RangeDifference;
import org.eclipse.compare.rangedifferencer.RangeDifferencer;
import org.eclipse.core.resources.IFile;
import org.eclipse.jface.text.BadLocationException;
import org.eclipse.jface.text.IDocument;
import org.eclipse.jface.text.IRegion;
import org.eclipse.ltk.core.refactoring.TextFileChange;
import org.eclipse.text.edits.DeleteEdit;
import org.eclipse.text.edits.InsertEdit;
import org.eclipse.text.edits.MultiTextEdit;
import org.eclipse.text.edits.ReplaceEdit;
import org.eclipse.text.edits.TextEdit;
import org.eclipse.text.edits.TextEditGroup;
/**
* This class creates an org.eclipse.ltk.core.refactoring.DocumentChange instance based on old and new text values
*
* @author Anton Kraev
*/
public class ChangeCreator {
private static final Logger log = LoggerFactory.getLogger(ChangeCreator.class);
private String label;
private IDocument oldDocument;
private IDocument newDocument;
private IFile oldFile;
public ChangeCreator(IFile oldFile, IDocument oldDocument, IDocument newDocument, String label) {
this.newDocument = newDocument;
this.oldDocument = oldDocument;
this.oldFile = oldFile;
this.label = label;
}
public TextFileChange createChange() throws Exception {
TextFileChange change = new TextFileChange(label, oldFile);
// change.setSaveMode(TextFileChange.FORCE_SAVE);
change.setEdit(new MultiTextEdit());
Object leftSide = new LineComparator(oldDocument);
Object rightSide = new LineComparator(newDocument);
RangeDifference[] differences = RangeDifferencer.findDifferences((IRangeComparator) leftSide,
(IRangeComparator) rightSide);
int insertOffset = 0;
for(int i = 0; i < differences.length; i++ ) {
RangeDifference curr = differences[i];
int startLine = 0;
// when comparing 2 files, only RangeDifference.CHANGE is possible, no need to test
if(curr.rightLength() == curr.leftLength()) {
// replace
startLine = curr.rightStart();
int endLine = curr.rightEnd() - 1;
for(int j = startLine; j <= endLine; j++ ) {
int newPos = curr.leftStart() - startLine + j;
String newText = newDocument.get(newDocument.getLineOffset(newPos), newDocument.getLineLength(newPos));
addEdit(change, startLine, new ReplaceEdit(oldDocument.getLineOffset(j), oldDocument.getLineLength(j),
newText));
}
} else if(curr.rightLength() > 0 && curr.leftLength() == 0) {
// insert
startLine = curr.rightStart();
int endLine = curr.rightEnd() - 1;
int posInsert = oldDocument.getLineOffset(curr.leftStart());
String newText = ""; //$NON-NLS-1$
for(int j = startLine; j <= endLine; j++ ) {
int newPos = curr.leftStart() - startLine + j + insertOffset;
newText += newDocument.get(newDocument.getLineOffset(newPos), newDocument.getLineLength(newPos));
}
if(newText.length() > 0) {
addEdit(change, startLine, new InsertEdit(posInsert, newText));
}
insertOffset += curr.rightEnd() - curr.rightStart();
} else if(curr.leftLength() > 0 && curr.rightLength() == 0) {
// delete
startLine = curr.leftStart();
int endLine = curr.leftEnd() - 1;
int startOffset = oldDocument.getLineOffset(startLine);
int endOffset = 0;
for(int j = startLine; j <= endLine; j++ ) {
endOffset += oldDocument.getLineLength(j);
}
addEdit(change, startLine, new DeleteEdit(startOffset, endOffset));
insertOffset -= (curr.leftEnd() - curr.leftStart());
} else {
// unhandled
}
}
return change;
}
private void addEdit(TextFileChange change, int startLine, TextEdit edit) {
change.addTextEditGroup(new TextEditGroup("Line " + (startLine + 1), edit));
change.addEdit(edit);
}
public static class LineComparator implements IRangeComparator {
private final IDocument document;
private final ArrayList<Integer> hashes;
/**
* Create a line comparator for the given document.
*
* @param document
*/
public LineComparator(IDocument document) {
this.document = document;
this.hashes = new ArrayList<Integer>(Arrays.asList(new Integer[document.getNumberOfLines()]));
}
/*
* @see org.eclipse.compare.rangedifferencer.IRangeComparator#getRangeCount()
*/
public int getRangeCount() {
return document.getNumberOfLines();
}
/*
* @see org.eclipse.compare.rangedifferencer.IRangeComparator#rangesEqual(int, org.eclipse.compare.rangedifferencer.IRangeComparator, int)
*/
public boolean rangesEqual(int thisIndex, IRangeComparator other, int otherIndex) {
try {
return getHash(thisIndex).equals(((LineComparator) other).getHash(otherIndex));
} catch(BadLocationException e) {
log.error("Problem comparing", e);
return false;
}
}
/*
* @see org.eclipse.compare.rangedifferencer.IRangeComparator#skipRangeComparison(int, int, org.eclipse.compare.rangedifferencer.IRangeComparator)
*/
public boolean skipRangeComparison(int length, int maxLength, IRangeComparator other) {
return false;
}
/**
* @param line the number of the line in the document to get the hash for
* @return the hash of the line
* @throws BadLocationException if the line number is invalid
*/
private Integer getHash(int line) throws BadLocationException {
Integer hash = hashes.get(line);
if(hash == null) {
IRegion lineRegion;
lineRegion = document.getLineInformation(line);
String lineContents = document.get(lineRegion.getOffset(), lineRegion.getLength());
hash = new Integer(computeDJBHash(lineContents));
hashes.set(line, hash);
}
return hash;
}
/**
* Compute a hash using the DJB hash algorithm
*
* @param string the string for which to compute a hash
* @return the DJB hash value of the string
*/
private int computeDJBHash(String string) {
int hash = 5381;
int len = string.length();
for(int i = 0; i < len; i++ ) {
hash = (hash << 5) + hash + string.charAt(i);
}
return hash;
}
}
}