1 files changed, 66 insertions, 0 deletions
diff --git a/app/services/lfs/file_transformer.rb b/app/services/lfs/file_transformer.rb
new file mode 100644
index 00000000000..69281ee3137
--- /dev/null
+++ b/app/services/lfs/file_transformer.rb
@@ -0,0 +1,66 @@
+module Lfs
+  # Usage: Calling `new_file` check to see if a file should be in LFS and
+  #        return a transformed result with `content` and `encoding` to commit.
+  #
+  #        For LFS an LfsObject linked to the project is stored and an LFS
+  #        pointer returned. If the file isn't in LFS the untransformed content
+  #        is returned to save in the commit.
+  #
+  # transformer = Lfs::FileTransformer.new(project, @branch_name)
+  # content_or_lfs_pointer = transformer.new_file(file_path, content).content
+  # create_transformed_commit(content_or_lfs_pointer)
+  #
+  class FileTransformer
+    attr_reader :project, :branch_name
+
+    delegate :repository, to: :project
+
+    def initialize(project, branch_name)
+      @project = project
+      @branch_name = branch_name
+    end
+
+    def new_file(file_path, file_content, encoding: nil)
+      if project.lfs_enabled? && lfs_file?(file_path)
+        file_content = Base64.decode64(file_content) if encoding == 'base64'
+        lfs_pointer_file = Gitlab::Git::LfsPointerFile.new(file_content)
+        lfs_object = create_lfs_object!(lfs_pointer_file, file_content)
+
+        link_lfs_object!(lfs_object)
+
+        Result.new(content: lfs_pointer_file.pointer, encoding: 'text')
+      else
+        Result.new(content: file_content, encoding: encoding)
+      end
+    end
+
+    class Result
+      attr_reader :content, :encoding
+
+      def initialize(content:, encoding:)
+        @content = content
+        @encoding = encoding
+      end
+    end
+
+    private
+
+    def lfs_file?(file_path)
+      cached_attributes.attributes(file_path)['filter'] == 'lfs'
+    end
+
+    def cached_attributes
+      @cached_attributes ||= Gitlab::Git::AttributesAtRefParser.new(repository, branch_name)
+    end
+
+    def create_lfs_object!(lfs_pointer_file, file_content)
+      LfsObject.find_or_create_by(oid: lfs_pointer_file.sha256, size: lfs_pointer_file.size) do |lfs_object|
+        lfs_object.file = CarrierWaveStringFile.new(file_content)
+      end
+    end
+
+    def link_lfs_object!(lfs_object)
+      project.lfs_objects << lfs_object
+    end
+  end
+end