1 files changed, 48 insertions, 0 deletions
diff --git a/lib/gitlab/ci/build/artifacts/adapters/gzip_stream.rb b/lib/gitlab/ci/build/artifacts/adapters/gzip_stream.rb
new file mode 100644
index 00000000000..ee3647f24fd
--- /dev/null
+++ b/lib/gitlab/ci/build/artifacts/adapters/gzip_stream.rb
@@ -0,0 +1,48 @@
+module Gitlab
+  module Ci
+    module Build
+      module Artifacts
+        module Adapters
+          class GzipStream
+            attr_reader :stream
+
+            InvalidStreamError = Class.new(StandardError)
+
+            def initialize(stream)
+              raise InvalidStreamError, "Stream is required" unless stream
+
+              @stream = stream
+            end
+
+            def each_blob
+              stream.seek(0)
+
+              until stream.eof?
+                gzip(stream) do |gz|
+                  yield gz.read, gz.orig_name
+                  unused = gz.unused&.length.to_i
+                  # pos has already reached to EOF at the moment
+                  # We rewind the pos to the top of unused files
+                  # to read next gzip stream, to support multistream archives
+                  # https://golang.org/src/compress/gzip/gunzip.go#L117
+                  stream.seek(-unused, IO::SEEK_CUR)
+                end
+              end
+            end
+
+            private
+
+            def gzip(stream, &block)
+              gz = Zlib::GzipReader.new(stream)
+              yield(gz)
+            rescue Zlib::Error => e
+              raise InvalidStreamError, e.message
+            ensure
+              gz&.finish
+            end
+          end
+        end
+      end
+    end
+  end
+end