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Add generateOriginalAndDiff method and test class #164

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Apr 27, 2023
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Add generateOriginalAndDiff method and test class #164

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cb2cc6f
Add generateOriginalAndDiff method and test class
1506085843 Mar 13, 2023
e791091
Add generateOriginalAndDiff method and test class.I split long code i…
1506085843 Mar 14, 2023
61407b4
fixes #164
1506085843 Mar 14, 2023
7d9d1ca
fix build issues
1506085843 Mar 22, 2023
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151 changes: 151 additions & 0 deletions java-diff-utils/src/main/java/com/github/difflib/UnifiedDiffUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,11 +19,15 @@
import com.github.difflib.patch.Chunk;
import com.github.difflib.patch.AbstractDelta;
import com.github.difflib.patch.Patch;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.stream.Collectors;

/**
*
Expand Down Expand Up @@ -313,4 +317,151 @@ private static List<String> getDeltaText(AbstractDelta<String> delta) {

private UnifiedDiffUtils() {
}

/**
* Compare the differences between two files and return to the original file and diff format
*
* (This method compares the original file with the comparison file to obtain a diff, and inserts the diff into the corresponding position of the original file.
* You can see all the differences and unmodified places from the original file.
* Also, this will be very easy and useful for making side-by-side comparison display applications,
* for example, if you use diff2html (https://github.com/rtfpessoa/diff2html#usage)
* Wait for tools to display your differences on html pages, you only need to insert the return value into your js code)
*
* @param original Original file content
* @param revised revised file content
*
*/
public static List<String> generateOriginalAndDiff(List<String> original, List<String> revised) {
return generateOriginalAndDiff(original, revised, null, null);
}


/**
* Compare the differences between two files and return to the original file and diff format
*
* (This method compares the original file with the comparison file to obtain a diff, and inserts the diff into the corresponding position of the original file.
* You can see all the differences and unmodified places from the original file.
* Also, this will be very easy and useful for making side-by-side comparison display applications,
* for example, if you use diff2html (https://github.com/rtfpessoa/diff2html#usage)
* Wait for tools to display your differences on html pages, you only need to insert the return value into your js code)
*
* @param original Original file content
* @param revised revised file content
* @param originalFileName Original file name
* @param revisedFileName revised file name
*/
public static List<String> generateOriginalAndDiff(List<String> original, List<String> revised, String originalFileName, String revisedFileName) {
String originalFileNameTemp = originalFileName;
String revisedFileNameTemp = originalFileName;
if (originalFileNameTemp == null) {
originalFileNameTemp = "original";
}
if (revisedFileNameTemp == null) {
revisedFileNameTemp = "revised";
}
Patch<String> patch = DiffUtils.diff(original, revised);
List<String> unifiedDiff = generateUnifiedDiff(originalFileNameTemp, revisedFileNameTemp, original, patch, 0);
if (unifiedDiff.isEmpty()) {
unifiedDiff.add("--- " + originalFileNameTemp);
unifiedDiff.add("+++ " + revisedFileNameTemp);
unifiedDiff.add("@@ -0,0 +0,0 @@");
} else if (unifiedDiff.size() >= 3 && !unifiedDiff.get(2).contains("@@ -1,")) {
unifiedDiff.set(1, unifiedDiff.get(1));
unifiedDiff.add(2, "@@ -0,0 +0,0 @@");
}
List<String> originalWithPrefix = original.stream().map(v -> " " + v).collect(Collectors.toList());
return insertOrig(originalWithPrefix, unifiedDiff);
}

//Insert the diff format to the original file
private static List<String> insertOrig(List<String> original, List<String> unifiedDiff) {
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Refactor the method to use more descriptive variable names. For example, instead of using "d", you can use "diff".

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The method is very long, it could be broken into multiple small methods to increase readability of the code.

List<String> result = new ArrayList<>();
List<List<String>> diffList = new ArrayList<>();
List<String> diff = new ArrayList<>();
for (int i = 0; i < unifiedDiff.size(); i++) {
String u = unifiedDiff.get(i);
if (u.startsWith("@@") && !"@@ -0,0 +0,0 @@".equals(u) && !u.contains("@@ -1,")) {
List<String> twoList = new ArrayList<>();
twoList.addAll(diff);
diffList.add(twoList);
diff.clear();
diff.add(u);
continue;
}
if (i == unifiedDiff.size() - 1) {
diff.add(u);
List<String> twoList = new ArrayList<>();
twoList.addAll(diff);
diffList.add(twoList);
diff.clear();
break;
}
diff.add(u);
}
insertOrig(diffList, result, original);
return result;
}

//Insert the diff format to the original file
private static void insertOrig(List<List<String>> diffList, List<String> result, List<String> original) {
for (int i = 0; i < diffList.size(); i++) {
List<String> diff = diffList.get(i);
List<String> nexDiff = i == diffList.size() - 1 ? null : diffList.get(i + 1);
String simb = i == 0 ? diff.get(2) : diff.get(0);
String nexSimb = nexDiff == null ? null : nexDiff.get(0);
insert(result, diff);
Map<String, Integer> map = getRowMap(simb);
if (null != nexSimb) {
Map<String, Integer> nexMap = getRowMap(nexSimb);
int start = 0;
if (map.get("orgRow") != 0) {
start = map.get("orgRow") + map.get("orgDel") - 1;
}
int end = nexMap.get("revRow") - 2;
insert(result, getOrigList(original, start, end));
}
if (simb.contains("@@ -1,") && null == nexSimb && map.get("orgDel") != original.size()) {
insert(result, getOrigList(original, 0, original.size() - 1));
} else if (null == nexSimb && (map.get("orgRow") + map.get("orgDel") - 1) < original.size()) {
int start = map.get("orgRow") + map.get("orgDel") - 1;
start = start == -1 ? 0 : start;
insert(result, getOrigList(original, start, original.size() - 1));
}
}
}

//Insert the unchanged content in the source file into result
private static void insert(List<String> result, List<String> noChangeContent) {
for (String ins : noChangeContent) {
result.add(ins);
}
}

//Parse the line containing @@ to get the modified line number to delete or add a few lines
private static Map<String, Integer> getRowMap(String str) {
Map<String, Integer> map = new HashMap<>();
if (str.startsWith("@@")) {
String[] sp = str.split(" ");
String org = sp[1];
String[] orgSp = org.split(",");
map.put("orgRow", Integer.valueOf(orgSp[0].substring(1)));
map.put("orgDel", Integer.valueOf(orgSp[1]));
String[] revSp = org.split(",");
map.put("revRow", Integer.valueOf(revSp[0].substring(1)));
map.put("revAdd", Integer.valueOf(revSp[1]));
}
return map;
}

//Get the specified part of the line from the original file
private static List<String> getOrigList(List<String> originalWithPrefix, int start, int end) {
List<String> list = new ArrayList<>();
if (originalWithPrefix.size() >= 1 && start <= end && end < originalWithPrefix.size()) {
int startTemp = start;
for (; startTemp <= end; startTemp++) {
list.add(originalWithPrefix.get(startTemp));
}
}
return list;
}
}
44 changes: 44 additions & 0 deletions java-diff-utils/src/test/java/com/github/difflib/examples/OriginalAndDiffTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,44 @@
package com.github.difflib.examples;

import com.github.difflib.TestConstants;
import com.github.difflib.UnifiedDiffUtils;
import org.junit.jupiter.api.Test;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import static java.util.stream.Collectors.joining;
import static org.junit.jupiter.api.Assertions.fail;

public class OriginalAndDiffTest {

@Test
public void testGenerateOriginalAndDiff() {
List<String> origLines = null;
List<String> revLines = null;
try {
origLines = fileToLines(TestConstants.MOCK_FOLDER + "original.txt");
revLines = fileToLines(TestConstants.MOCK_FOLDER + "revised.txt");
} catch (IOException e) {
fail(e.getMessage());
}

List<String> originalAndDiff = UnifiedDiffUtils.generateOriginalAndDiff(origLines, revLines);
System.out.println(originalAndDiff.stream().collect(joining("\n")));
}

public static List<String> fileToLines(String filename) throws FileNotFoundException, IOException {
List<String> lines = new ArrayList<>();
String line = "";
try (BufferedReader in = new BufferedReader(new FileReader(filename))) {
while ((line = in.readLine()) != null) {
lines.add(line);
}
}
return lines;
}
}