Display partial diff for commit comments

src/main/scala/gitbucket/core/view/helpers.scala

@@ -3,6 +3,7 @@ package gitbucket.core.view
 import java.text.SimpleDateFormat
 import java.util.{Date, Locale, TimeZone}
 
+import com.nimbusds.jose.util.JSONObjectUtils
 import gitbucket.core.controller.Context
 import gitbucket.core.model.CommitState
 import gitbucket.core.plugin.{PluginRegistry, RenderRequest}
@@ -462,4 +463,44 @@ object helpers extends AvatarImageProvider with LinkConverter with RequestCache
    */
   def readableSize(size: Option[Long]): String = FileUtil.readableSize(size.getOrElse(0))
 
+  /**
+   * Make HTML fragment of the partial diff for a comment on a line of diff.
+   *
+   * @param jsonString JSON string which is stored in COMMIT_COMMENT table.
+   * @return HTML fragment of diff
+   */
+  def diff(jsonString: String): Html = {
+    import org.json4s._
+    import org.json4s.jackson.JsonMethods._
+    implicit val formats = DefaultFormats
+
+    val diff = parse(jsonString).extract[Seq[CommentDiffLine]]
+
+    val sb = new StringBuilder()
+    sb.append("<table class=\"diff inlinediff\">")
+    diff.foreach { line =>
+      sb.append("<tr>")
+      sb.append(s"""<th class="line-num oldline ${line.`type`}">""")
+      line.oldLine.foreach { oldLine =>
+        sb.append(oldLine)
+      }
+      sb.append("</th>")
+      sb.append(s"""<th class="line-num newline ${line.`type`}">""")
+      line.newLine.foreach { newLine =>
+        sb.append(newLine)
+      }
+      sb.append("</th>")
+
+      sb.append(s"""<td class="body ${line.`type`}">""")
+      sb.append(StringUtil.escapeHtml(line.text))
+      sb.append("</td>")
+      sb.append("</tr>")
+    }
+    sb.append("</table>")
+
+    Html(sb.toString())
+  }
+
+  case class CommentDiffLine(newLine: Option[String], oldLine: Option[String], `type`: String, text: String)
+
 }

src/main/twirl/gitbucket/core/helper/commitcomments.scala.html

@@ -10,6 +10,11 @@
       <a href="@helpers.url(repository)/commit/@comments.comments.head.commitId" class="monospace">@comments.comments.head.commitId.substring(0, 7)</a>
     </span>
   </div>
+  @comments.comments.headOption.map { comment =>
+    @comment.diff.map { diff =>
+      @helpers.diff(diff)
+    }
+  }
   <div class="panel-body">
     @comments.comments.map { comment =>
       @gitbucket.core.helper.html.commitcomment(comment, hasWritePermission, repository, latestCommitId)

src/main/twirl/gitbucket/core/pulls/conversation.scala.html

@@ -15,6 +15,7 @@
   flash: Map[String, String])(implicit context: gitbucket.core.controller.Context)
 @import gitbucket.core.view.helpers
 @gitbucket.core.pulls.html.menu("conversation", issue, pullreq, commits, comments, isManageable, repository, flash){
+  <link href="@helpers.assets("/vendors/jsdifflib/diffview.css")" type="text/css" rel="stylesheet" />
   <div class="col-md-9">
     <div id="comment-list">
       @gitbucket.core.issues.html.commentlist(Some(issue), comments.toList, isManageable, repository, Some(pullreq))