com.cloudbees.diff.UnifiedDiff Maven / Gradle / Ivy
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Repackaged the code from NetBeans
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright 1997-2007 Sun Microsystems, Inc. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common
* Development and Distribution License("CDDL") (collectively, the
* "License"). You may not use this file except in compliance with the
* License. You can obtain a copy of the License at
* http://www.netbeans.org/cddl-gplv2.html
* or nbbuild/licenses/CDDL-GPL-2-CP. See the License for the
* specific language governing permissions and limitations under the
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* particular file as subject to the "Classpath" exception as provided
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*
* The Original Software is NetBeans. The Initial Developer of the Original
* Software is Sun Microsystems, Inc. Portions Copyright 1997-2007 Sun
* Microsystems, Inc. All Rights Reserved.
*
* If you wish your version of this file to be governed by only the CDDL
* or only the GPL Version 2, indicate your decision by adding
* "[Contributor] elects to include this software in this distribution
* under the [CDDL or GPL Version 2] license." If you do not indicate a
* single choice of license, a recipient has the option to distribute
* your version of this file under either the CDDL, the GPL Version 2 or
* to extend the choice of license to its licensees as provided above.
* However, if you add GPL Version 2 code and therefore, elected the GPL
* Version 2 license, then the option applies only if the new code is
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*/
package com.cloudbees.diff;
import org.apache.commons.io.IOUtils;
import java.io.*;
import java.util.List;
/**
* Unified diff engine.
*
* @author Maros Sandor
*/
final class UnifiedDiff {
private final TextDiffInfo diffInfo;
private final int numContextLine;
private BufferedReader baseReader;
private BufferedReader modifiedReader;
private final String newline;
private boolean baseEndsWithNewline;
private boolean modifiedEndsWithNewline;
private int currentBaseLine;
private int currentModifiedLine;
public UnifiedDiff(TextDiffInfo diffInfo, int numContextLine) {
this.diffInfo = diffInfo;
this.numContextLine = numContextLine;
currentBaseLine = 1;
currentModifiedLine = 1;
this.newline = System.getProperty("line.separator");
}
public String computeDiff() throws IOException {
baseReader = checkEndingNewline(diffInfo.createFirstReader(), true);
modifiedReader = checkEndingNewline(diffInfo.createSecondReader(), false);
StringBuilder buffer = new StringBuilder();
buffer.append("--- ");
buffer.append(diffInfo.getName1());
buffer.append(newline);
buffer.append("+++ ");
buffer.append(diffInfo.getName2());
buffer.append(newline);
List diffs = diffInfo.getDifferences();
for (int currentDifference = 0; currentDifference < diffs.size(); ) {
// the new hunk will span differences from currentDifference to lastDifference (exclusively)
int lastDifference = getLastIndex(currentDifference);
Hunk hunk = computeHunk(currentDifference, lastDifference);
dumpHunk(buffer, hunk);
currentDifference = lastDifference;
}
return buffer.toString();
}
private BufferedReader checkEndingNewline(Reader reader, boolean isBase) throws IOException {
StringWriter sw = new StringWriter();
copyStreamsCloseAll(sw, reader);
String s = sw.toString();
char endingChar = s.length() == 0 ? 0 : s.charAt(s.length() - 1);
if (isBase) {
baseEndsWithNewline = endingChar == '\n' || endingChar == '\r';
} else {
modifiedEndsWithNewline = endingChar == '\n' || endingChar == '\r';
}
return new BufferedReader(new StringReader(s));
}
private Hunk computeHunk(int firstDifference, int lastDifference) throws IOException {
Hunk hunk = new Hunk();
Difference firstDiff = diffInfo.getDifferences().get(firstDifference);
int contextLines = numContextLine;
int skipLines;
if (firstDiff.getType() == Difference.ADD) {
if (contextLines > firstDiff.getFirstStart()) {
contextLines = firstDiff.getFirstStart();
}
skipLines = firstDiff.getFirstStart() - contextLines - currentBaseLine + 1;
} else {
if (contextLines >= firstDiff.getFirstStart()) {
contextLines = firstDiff.getFirstStart() - 1;
}
skipLines = firstDiff.getFirstStart() - contextLines - currentBaseLine;
}
// move file pointers to the beginning of hunk
while (skipLines-- > 0) {
readLine(baseReader);
readLine(modifiedReader);
}
hunk.baseStart = currentBaseLine;
hunk.modifiedStart = currentModifiedLine;
// output differences with possible contextual lines in-between
for (int i = firstDifference; i < lastDifference; i++) {
Difference diff = diffInfo.getDifferences().get(i);
writeContextLines(hunk, diff.getFirstStart() - currentBaseLine + ((diff.getType() == Difference.ADD) ? 1 : 0));
if (diff.getFirstEnd() > 0) {
int n = diff.getFirstEnd() - diff.getFirstStart() + 1;
outputLines(hunk, baseReader, "-", n);
hunk.baseCount += n;
if (!baseEndsWithNewline && i == diffInfo.getDifferences().size() - 1 && diff.getFirstEnd() == currentBaseLine - 1) {
hunk.lines.add(Hunk.ENDING_NEWLINE);
}
}
if (diff.getSecondEnd() > 0) {
int n = diff.getSecondEnd() - diff.getSecondStart() + 1;
outputLines(hunk, modifiedReader, "+", n);
hunk.modifiedCount += n;
if (!modifiedEndsWithNewline && i == diffInfo.getDifferences().size() - 1 && diff.getSecondEnd() == currentModifiedLine - 1) {
hunk.lines.add(Hunk.ENDING_NEWLINE);
}
}
}
// output bottom context lines
writeContextLines(hunk, numContextLine);
if (hunk.modifiedCount == 0) hunk.modifiedStart = 0; // empty file
if (hunk.baseCount == 0) hunk.baseStart = 0; // empty file
return hunk;
}
private void writeContextLines(Hunk hunk, int count) throws IOException {
while (count-- > 0) {
String line = readLine(baseReader);
if (line == null) return;
hunk.lines.add(" " + line);
readLine(modifiedReader); // move the modified file pointer as well
hunk.baseCount++;
hunk.modifiedCount++;
}
}
private String readLine(BufferedReader reader) throws IOException {
String s = reader.readLine();
if (s != null) {
if (reader == baseReader) currentBaseLine++;
if (reader == modifiedReader) currentModifiedLine++;
}
return s;
}
private void outputLines(Hunk hunk, BufferedReader reader, String mode, int n) throws IOException {
while (n-- > 0) {
String line = readLine(reader);
hunk.lines.add(mode + line);
}
}
private int getLastIndex(int firstIndex) {
int contextLines = numContextLine * 2;
List diffs = diffInfo.getDifferences();
for (++firstIndex; firstIndex < diffs.size(); firstIndex++) {
Difference prevDiff = diffs.get(firstIndex - 1);
Difference currentDiff = diffs.get(firstIndex);
int prevEnd = 1 + ((prevDiff.getType() == Difference.ADD) ? prevDiff.getFirstStart() : prevDiff.getFirstEnd());
int curStart = (currentDiff.getType() == Difference.ADD) ? (currentDiff.getFirstStart() + 1) : currentDiff.getFirstStart();
if (curStart - prevEnd > contextLines) {
break;
}
}
return firstIndex;
}
private void dumpHunk(StringBuilder buffer, Hunk hunk) {
buffer.append("@@ -");
buffer.append(Integer.toString(hunk.baseStart));
if (hunk.baseCount != 1) {
buffer.append(",");
buffer.append(Integer.toString(hunk.baseCount));
}
buffer.append(" +");
buffer.append(Integer.toString(hunk.modifiedStart));
if (hunk.modifiedCount != 1) {
buffer.append(",");
buffer.append(Integer.toString(hunk.modifiedCount));
}
buffer.append(" @@");
buffer.append(newline);
for (String line : hunk.lines) {
buffer.append(line);
buffer.append(newline);
}
}
private static void copyStreamsCloseAll(Writer writer, Reader reader) throws IOException {
IOUtils.copy(reader,writer);
writer.close();
reader.close();
}
}
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