1 files changed, 112 insertions, 0 deletions
diff --git a/app/services/packages/debian/extract_changes_metadata_service.rb b/app/services/packages/debian/extract_changes_metadata_service.rb
new file mode 100644
index 00000000000..eb5baa7e53f
--- /dev/null
+++ b/app/services/packages/debian/extract_changes_metadata_service.rb
@@ -0,0 +1,112 @@
+# frozen_string_literal: true
+
+module Packages
+  module Debian
+    class ExtractChangesMetadataService
+      include Gitlab::Utils::StrongMemoize
+
+      ExtractionError = Class.new(StandardError)
+
+      def initialize(package_file)
+        @package_file = package_file
+        @entries = {}
+      end
+
+      def execute
+        {
+          file_type: file_type,
+          architecture: metadata[:architecture],
+          fields: fields,
+          files: files
+        }
+      rescue ActiveModel::ValidationError => e
+        raise ExtractionError.new(e.message)
+      end
+
+      private
+
+      def metadata
+        strong_memoize(:metadata) do
+          ::Packages::Debian::ExtractMetadataService.new(@package_file).execute
+        end
+      end
+
+      def file_type
+        metadata[:file_type]
+      end
+
+      def fields
+        metadata[:fields]
+      end
+
+      def files
+        strong_memoize(:files) do
+          raise ExtractionError.new("is not a changes file") unless file_type == :changes
+          raise ExtractionError.new("Files field is missing") if fields['Files'].blank?
+          raise ExtractionError.new("Checksums-Sha1 field is missing") if fields['Checksums-Sha1'].blank?
+          raise ExtractionError.new("Checksums-Sha256 field is missing") if fields['Checksums-Sha256'].blank?
+
+          init_entries_from_files
+          entries_from_checksums_sha1
+          entries_from_checksums_sha256
+          entries_from_package_files
+
+          @entries
+        end
+      end
+
+      def init_entries_from_files
+        each_lines_for('Files') do |line|
+          md5sum, size, section, priority, filename = line.split
+          entry = FileEntry.new(
+            filename: filename,
+            size: size.to_i,
+            md5sum: md5sum,
+            section: section,
+            priority: priority)
+
+          @entries[filename] = entry
+        end
+      end
+
+      def entries_from_checksums_sha1
+        each_lines_for('Checksums-Sha1') do |line|
+          sha1sum, size, filename = line.split
+          entry = @entries[filename]
+          raise ExtractionError.new("#{filename} is listed in Checksums-Sha1 but not in Files") unless entry
+          raise ExtractionError.new("Size for #{filename} in Files and Checksums-Sha1 differ") unless entry.size == size.to_i
+
+          entry.sha1sum = sha1sum
+        end
+      end
+
+      def entries_from_checksums_sha256
+        each_lines_for('Checksums-Sha256') do |line|
+          sha256sum, size, filename = line.split
+          entry = @entries[filename]
+          raise ExtractionError.new("#{filename} is listed in Checksums-Sha256 but not in Files") unless entry
+          raise ExtractionError.new("Size for #{filename} in Files and Checksums-Sha256 differ") unless entry.size == size.to_i
+
+          entry.sha256sum = sha256sum
+        end
+      end
+
+      def each_lines_for(field)
+        fields[field].split("\n").each do |line|
+          next if line.blank?
+
+          yield(line)
+        end
+      end
+
+      def entries_from_package_files
+        @entries.each do |filename, entry|
+          entry.package_file = ::Packages::PackageFileFinder.new(@package_file.package, filename).execute!
+          entry.validate!
+        rescue ActiveRecord::RecordNotFound
+          raise ExtractionError.new("#{filename} is listed in Files but was not uploaded")
+        end
+      end
+    end
+  end
+end