使用JGIT，如何检索添加/删除的行的行号 [英] Using the JGIT, how can I retrieve the line numbers of added/deleted lines

问题描述

假定以下代码段已提交到Git存储库：

Assuming the following piece of code is committed to a Git repository:

int test(){
   int a = 3;
   int b = 4;
   int c = a + b;
   return c;
}

，后来更新为

int test(){
  return 7;
}

我目前有一种使用JGit API来访问Git的方法上面提交的存储库，并输出类似于以下内容的字符串：

I currently have a method which uses the JGit API in order to access the Git repository where the above are committed and outputs a string which is similar to the following:

int test(){
-int a = 3;
-int b = 4;
-int c = a + b;
-return c;
+return 7;
}

现在，我的要求已更改，想知道该行的行号。仅更改线路。所以我想要类似以下内容的东西：

Now, my requirements have changed and would like to know the line numbers of the changed lines only. So I would want something like the following:

2 -int a = 3;
3 -int b = 4;
4 -int c = a + b;
5 -return c;
2 +return 7;

基本上，与GitHub应用程序在更新时提供的信息相同。

Basically, the same information that the GitHub application gives when an update is made.

任何帮助将不胜感激：）

Any help would be greatly appreciated :)

如何计算-/ +行的代码段：

snippet of how the -/+ lines are computed:

            String oldHash = "ee3e216ab5047748a22e9ec5ad3e92834704f0cc";
        Git git = null;
        try {
            //the path where the repo is.
            git = Git.open(new File("C:\\Users\\Administrator\\Documents\\GitHub\\Trial"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        Repository repository = git.getRepository();
        ObjectId old = null;
        ObjectId head = null;
        //a new reader to read objects from getObjectDatabase()
        ObjectReader reader = repository.newObjectReader();
        //Create a new parser.
        CanonicalTreeParser oldTreeIter = new CanonicalTreeParser();
        CanonicalTreeParser newTreeIter = new CanonicalTreeParser();
        List<DiffEntry> diffs = null;

        try {
            //parse a git repository string and return an ObjectId
            old = repository.resolve(oldHash + "^{tree}");
            head = repository.resolve("HEAD^{tree}");
            //Reset this parser to walk through the given tree
            oldTreeIter.reset(reader, old);
            newTreeIter.reset(reader, head);
            diffs = git.diff()//Returns a command object to execute a diff command
                    .setNewTree(newTreeIter)
                    .setOldTree(oldTreeIter)
                    .call();//returns a DiffEntry for each path which is different

        } catch (RevisionSyntaxException | IOException | GitAPIException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        //DiffLineCountFilter d = new DiffLineCountFilter();
        //out is the stream the formatter will write to
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        //Create a new formatter with a default level of context.
        DiffFormatter df = new DiffFormatter(out);
        //Set the repository the formatter can load object contents from.
        df.setRepository(git.getRepository());
        ArrayList<String> diffText = new ArrayList<String>();
        //A DiffEntry is 'A value class representing a change to a file' therefore for each file you have a diff entry
        for(DiffEntry diff : diffs)
        {
           try {
                 //Format a patch script for one file entry.
                df.format(diff);
                RawText r = new RawText(out.toByteArray());
                r.getLineDelimiter();


                diffText.add(out.toString());
                out.reset();
            } catch (IOException e) {
                e.printStackTrace();
            }

         }

推荐答案

对于可能遇到此问题的任何人来说只是一个提示。我没有设法获得添加和删除的行的行号，但是我确实得到了一个仅包含添加和删除的行而没有其他未更改的字符串的字符串。

Just a tip for anyone who might have this problem. I did not manage to get the line numbers of the added and deleted lines but I did manage to get a string which contains only the added and deleted lines without the other lines which were not changed.

只需添加以下行即可完成：

This was simply done by adding the line:

   df.setContext(0);

我在上一行之前提供的摘录中

in the snippet I provided above right before the line

   df.format(diff);

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