1 files changed, 62 insertions, 0 deletions
diff --git a/lib/gitlab/conflict/parser.rb b/lib/gitlab/conflict/parser.rb
new file mode 100644
index 00000000000..6eccded7872
--- /dev/null
+++ b/lib/gitlab/conflict/parser.rb
@@ -0,0 +1,62 @@
+module Gitlab
+  module Conflict
+    class Parser
+      class ParserError < StandardError
+      end
+
+      class UnexpectedDelimiter < ParserError
+      end
+
+      class MissingEndDelimiter < ParserError
+      end
+
+      class UnmergeableFile < ParserError
+      end
+
+      def parse(text, our_path:, their_path:, parent_file: nil)
+        raise UnmergeableFile if text.blank? # Typically a binary file
+        raise UnmergeableFile if text.length > 102400
+
+        line_obj_index = 0
+        line_old = 1
+        line_new = 1
+        type = nil
+        lines = []
+        conflict_start = "<<<<<<< #{our_path}"
+        conflict_middle = '======='
+        conflict_end = ">>>>>>> #{their_path}"
+
+        text.each_line.map do |line|
+          full_line = line.delete("\n")
+
+          if full_line == conflict_start
+            raise UnexpectedDelimiter unless type.nil?
+
+            type = 'new'
+          elsif full_line == conflict_middle
+            raise UnexpectedDelimiter unless type == 'new'
+
+            type = 'old'
+          elsif full_line == conflict_end
+            raise UnexpectedDelimiter unless type == 'old'
+
+            type = nil
+          elsif line[0] == '\\'
+            type = 'nonewline'
+            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new, parent_file: parent_file)
+          else
+            lines << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new, parent_file: parent_file)
+            line_old += 1 if type != 'new'
+            line_new += 1 if type != 'old'
+
+            line_obj_index += 1
+          end
+        end
+
+        raise MissingEndDelimiter unless type.nil?
+
+        lines
+      end
+    end
+  end
+end