1 files changed, 51 insertions, 0 deletions
diff --git a/lib/gitlab/gfm/uploads_rewriter.rb b/lib/gitlab/gfm/uploads_rewriter.rb
new file mode 100644
index 00000000000..abc8c8c55e6
--- /dev/null
+++ b/lib/gitlab/gfm/uploads_rewriter.rb
@@ -0,0 +1,51 @@
+module Gitlab
+  module Gfm
+    ##
+    # Class that rewrites markdown links for uploads
+    #
+    # Using a pattern defined in `FileUploader` it copies files to a new
+    # project and rewrites all links to uploads in in a given text.
+    #
+    #
+    class UploadsRewriter
+      def initialize(text, source_project, _current_user)
+        @text = text
+        @source_project = source_project
+        @pattern = FileUploader::MARKDOWN_PATTERN
+      end
+
+      def rewrite(target_project)
+        return @text unless needs_rewrite?
+
+        @text.gsub(@pattern) do |markdown|
+          file = find_file(@source_project, $~[:secret], $~[:file])
+          return markdown unless file.try(:exists?)
+
+          new_uploader = FileUploader.new(target_project)
+          new_uploader.store!(file)
+          new_uploader.to_markdown
+        end
+      end
+
+      def needs_rewrite?
+        files.any?
+      end
+
+      def files
+        referenced_files = @text.scan(@pattern).map do
+          find_file(@source_project, $~[:secret], $~[:file])
+        end
+
+        referenced_files.compact.select(&:exists?)
+      end
+
+      private
+
+      def find_file(project, secret, file)
+        uploader = FileUploader.new(project, secret)
+        uploader.retrieve_from_store!(file)
+        uploader.file
+      end
+    end
+  end
+end