1 files changed, 24 insertions, 0 deletions
diff --git a/lib/gitlab/front_matter.rb b/lib/gitlab/front_matter.rb
new file mode 100644
index 00000000000..7612bd36aca
--- /dev/null
+++ b/lib/gitlab/front_matter.rb
@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+module Gitlab
+  module FrontMatter
+    DELIM_LANG = {
+      '---' => 'yaml',
+      '+++' => 'toml',
+      ';;;' => 'json'
+    }.freeze
+
+    DELIM = Regexp.union(DELIM_LANG.keys)
+
+    PATTERN = %r{
+      \A(?:[^\r\n]*coding:[^\r\n]*)?         # optional encoding line
+      \s*
+      ^(?<delim>#{DELIM})[ \t]*(?<lang>\S*)  # opening front matter marker (optional language specifier)
+      \s*
+      ^(?<front_matter>.*?)                  # front matter block content (not greedy)
+      \s*
+      ^(\k<delim> | \.{3})                   # closing front matter marker
+      \s*
+    }mx.freeze
+  end
+end