Add Tabular Diff for CSV files (#14661)

Implements request #14320 The rendering of CSV files does match the diff style.

* Moved CSV logic into base package.

* Added method to create a tabular diff.

* Added CSV compare context.

* Added CSV diff template.

* Use new table style in CSV markup.

* Added file size limit for CSV rendering.

* Display CSV parser errors in diff.

* Lazy read single file.

* Lazy read rows for full diff.

* Added unit tests for various CSV changes.

3 files changed, 72 insertions, 25 deletions

diff --git a/web_src/js/index.js b/web_src/js/index.js
index de9b99d4ef..aa9b3be004 100644
--- a/web_src/js/index.js
+++ b/web_src/js/index.js
@@ -2489,6 +2489,18 @@ function initIssueReferenceRepositorySearch() {
     });
 }
 
+function initFileViewToggle() {
+  $('.file-view-toggle').on('click', function() {
+    const $this = $(this);
+    $this.parent().children().removeClass('active');
+    $this.addClass('active');
+
+    const $target = $($this.data('toggle-selector'));
+    $target.parent().children().addClass('hide');
+    $target.removeClass('hide');
+  });
+}
+
 function initLinkAccountView() {
   const $lnkUserPage = $('.page-content.user.link-account');
   if ($lnkUserPage.length === 0) {
@@ -2756,6 +2768,7 @@ $(document).ready(async () => {
   initTableSort();
   initNotificationsTable();
   initPullRequestMergeInstruction();
+  initFileViewToggle();
   initReleaseEditor();
   initRelease();
 
diff --git a/web_src/less/_markdown.less b/web_src/less/_markdown.less
index 6bb0bf4328..09c94f0678 100644
--- a/web_src/less/_markdown.less
+++ b/web_src/less/_markdown.less
@@ -473,31 +473,6 @@
     box-shadow: inset 0 -1px 0 var(--color-secondary);
   }
 
-  .csv-data td,
-  .csv-data th {
-    padding: 5px;
-    overflow: hidden;
-    font-size: 12px;
-    line-height: 1;
-    text-align: left;
-    white-space: nowrap;
-  }
-
-  .csv-data .blob-num {
-    padding: 10px 8px 9px;
-    text-align: right;
-    border: 0;
-  }
-
-  .csv-data tr {
-    border-top: 0;
-  }
-
-  .csv-data th {
-    font-weight: 600;
-    border-top: 0;
-  }
-
   .ui.list .list,
   ol.ui.list ol,
   ul.ui.list ul {
diff --git a/web_src/less/_repository.less b/web_src/less/_repository.less
index c49da7b395..10e5736787 100644
--- a/web_src/less/_repository.less
+++ b/web_src/less/_repository.less
@@ -1455,6 +1455,65 @@
     }
   }
 
+  .data-table {
+    width: 100%;
+
+    tr {
+      border-top: 0;
+    }
+
+    td,
+    th {
+      padding: 5px !important;
+      overflow: hidden;
+      font-size: 12px;
+      text-align: left;
+      white-space: nowrap;
+      border: 1px solid var(--color-secondary);
+    }
+
+    td {
+      white-space: pre-line;
+    }
+
+    th {
+      font-weight: 600;
+      background: var(--color-box-header);
+      border-top: 0;
+    }
+
+    td.added,
+    th.added,
+    tr.added {
+      background-color: var(--color-diff-added-row-bg) !important;
+    }
+
+    td.removed,
+    th.removed,
+    tr.removed {
+      background-color: var(--color-diff-removed-row-bg) !important;
+    }
+
+    tbody.section {
+      border-top: 2px solid var(--color-secondary);
+    }
+
+    .line-num {
+      width: 1%;
+      min-width: 50px;
+      font-family: monospace;
+      line-height: 20px;
+      color: var(--color-secondary-dark-2);
+      white-space: nowrap;
+      vertical-align: top;
+      cursor: pointer;
+      user-select: none;
+      text-align: right;
+      background: var(--color-body);
+      border: 0;
+    }
+  }
+
   .diff-detail-box {
     padding: 7px 0;
     background: var(--color-body);