Add latest changes from gitlab-org/gitlab@master

1 files changed, 157 insertions, 17 deletions

diff --git a/lib/gitlab/json.rb b/lib/gitlab/json.rb
index 5b6689dbefe..6c254e171dc 100644
--- a/lib/gitlab/json.rb
+++ b/lib/gitlab/json.rb
@@ -1,59 +1,199 @@
 # frozen_string_literal: true
 
+# This is a GitLab-specific JSON interface. You should use this instead
+# of using `JSON` directly. This allows us to swap the adapter and handle
+# legacy issues.
+
 module Gitlab
   module Json
     INVALID_LEGACY_TYPES = [String, TrueClass, FalseClass].freeze
 
     class << self
-      def parse(string, *args, **named_args)
-        legacy_mode = legacy_mode_enabled?(named_args.delete(:legacy_mode))
-        data = adapter.parse(string, *args, **named_args)
+      # Parse a string and convert it to a Ruby object
+      #
+      # @param string [String] the JSON string to convert to Ruby objects
+      # @param opts [Hash] an options hash in the standard JSON gem format
+      # @return [Boolean, String, Array, Hash]
+      # @raise [JSON::ParserError] raised if parsing fails
+      def parse(string, opts = {})
+        # First we should ensure this really is a string, not some other
+        # type which purports to be a string. This handles some legacy
+        # usage of the JSON class.
+        string = string.to_s unless string.is_a?(String)
+
+        legacy_mode = legacy_mode_enabled?(opts.delete(:legacy_mode))
+        data = adapter_load(string, opts)
 
         handle_legacy_mode!(data) if legacy_mode
 
         data
       end
 
-      def parse!(string, *args, **named_args)
-        legacy_mode = legacy_mode_enabled?(named_args.delete(:legacy_mode))
-        data = adapter.parse!(string, *args, **named_args)
+      alias_method :parse!, :parse
+
+      # Restricted method for converting a Ruby object to JSON. If you
+      # need to pass options to this, you should use `.generate` instead,
+      # as the underlying implementation of this varies wildly based on
+      # the adapter in use.
+      #
+      # @param object [Object] the object to convert to JSON
+      # @return [String]
+      def dump(object)
+        adapter_dump(object)
+      end
 
-        handle_legacy_mode!(data) if legacy_mode
+      # Generates JSON for an object. In Oj this takes fewer options than .dump,
+      # in the JSON gem this is the only method which takes an options argument.
+      #
+      # @param object [Hash, Array, Object] must be hash, array, or an object that responds to .to_h or .to_json
+      # @param opts [Hash] an options hash with fewer supported settings than .dump
+      # @return [String]
+      def generate(object, opts = {})
+        adapter_generate(object, opts)
+      end
 
-        data
+      # Generates JSON for an object and makes it look purdy
+      #
+      # The Oj variant in this looks seriously weird but these are the settings
+      # needed to emulate the style generated by the JSON gem.
+      #
+      # NOTE: This currently ignores Oj, because Oj doesn't generate identical
+      #       formatting, issue: https://github.com/ohler55/oj/issues/608
+      #
+      # @param object [Hash, Array, Object] must be hash, array, or an object that responds to .to_h or .to_json
+      # @param opts [Hash] an options hash with fewer supported settings than .dump
+      # @return [String]
+      def pretty_generate(object, opts = {})
+        ::JSON.pretty_generate(object, opts)
       end
 
-      def dump(*args)
-        adapter.dump(*args)
+      private
+
+      # Convert JSON string into Ruby through toggleable adapters.
+      #
+      # Must rescue adapter-specific errors and return `parser_error`, and
+      # must also standardize the options hash to support each adapter as
+      # they all take different options.
+      #
+      # @param string [String] the JSON string to convert to Ruby objects
+      # @param opts [Hash] an options hash in the standard JSON gem format
+      # @return [Boolean, String, Array, Hash]
+      # @raise [JSON::ParserError]
+      def adapter_load(string, *args, **opts)
+        opts = standardize_opts(opts)
+
+        if enable_oj?
+          Oj.load(string, opts)
+        else
+          ::JSON.parse(string, opts)
+        end
+      rescue Oj::ParseError, Encoding::UndefinedConversionError => ex
+        raise parser_error.new(ex)
       end
 
-      def generate(*args)
-        adapter.generate(*args)
+      # Take a Ruby object and convert it to a string. This method varies
+      # based on the underlying JSON interpreter. Oj treats this like JSON
+      # treats `.generate`. JSON.dump takes no options.
+      #
+      # This supports these options to ensure this difference is recorded here,
+      # as it's very surprising. The public interface is more restrictive to
+      # prevent adapter-specific options being passed.
+      #
+      # @overload adapter_dump(object, opts)
+      #   @param object [Object] the object to convert to JSON
+      #   @param opts [Hash] options as named arguments, only supported by Oj
+      #
+      # @overload adapter_dump(object, anIO, limit)
+      #   @param object [Object] the object, will have JSON.generate called on it
+      #   @param anIO [Object] an IO-like object that responds to .write, default nil
+      #   @param limit [Fixnum] the nested array/object limit, default nil
+      #   @raise [ArgumentError] when depth limit exceeded
+      #
+      # @return [String]
+      def adapter_dump(object, *args, **opts)
+        if enable_oj?
+          Oj.dump(object, opts)
+        else
+          ::JSON.dump(object, *args)
+        end
       end
 
-      def pretty_generate(*args)
-        adapter.pretty_generate(*args)
+      # Generates JSON for an object but with fewer options, using toggleable adapters.
+      #
+      # @param object [Hash, Array, Object] must be hash, array, or an object that responds to .to_h or .to_json
+      # @param opts [Hash] an options hash with fewer supported settings than .dump
+      # @return [String]
+      def adapter_generate(object, opts = {})
+        opts = standardize_opts(opts)
+
+        if enable_oj?
+          Oj.generate(object, opts)
+        else
+          ::JSON.generate(object, opts)
+        end
       end
 
-      private
+      # Take a JSON standard options hash and standardize it to work across adapters
+      # An example of this is Oj taking :symbol_keys instead of :symbolize_names
+      #
+      # @param opts [Hash, Nil]
+      # @return [Hash]
+      def standardize_opts(opts)
+        opts ||= {}
+
+        if enable_oj?
+          opts[:mode] = :rails
+          opts[:symbol_keys] = opts[:symbolize_keys] || opts[:symbolize_names]
+        end
 
-      def adapter
-        ::JSON
+        opts
       end
 
+      # The standard parser error we should be returning. Defined in a method
+      # so we can potentially override it later.
+      #
+      # @return [JSON::ParserError]
       def parser_error
         ::JSON::ParserError
       end
 
+      # @param [Nil, Boolean] an extracted :legacy_mode key from the opts hash
+      # @return [Boolean]
       def legacy_mode_enabled?(arg_value)
         arg_value.nil? ? false : arg_value
       end
 
+      # If legacy mode is enabled, we need to raise an error depending on the values
+      # provided in the string. This will be deprecated.
+      #
+      # @param data [Boolean, String, Array, Hash, Object]
+      # @return [Boolean, String, Array, Hash, Object]
+      # @raise [JSON::ParserError]
       def handle_legacy_mode!(data)
+        return data unless feature_table_exists?
         return data unless Feature.enabled?(:json_wrapper_legacy_mode, default_enabled: true)
 
         raise parser_error if INVALID_LEGACY_TYPES.any? { |type| data.is_a?(type) }
       end
+
+      # @return [Boolean]
+      def enable_oj?
+        return false unless feature_table_exists?
+
+        Feature.enabled?(:oj_json, default_enabled: true)
+      end
+
+      # There are a variety of database errors possible when checking the feature
+      # flags at the wrong time during boot, e.g. during migrations. We don't care
+      # about these errors, we just need to ensure that we skip feature detection
+      # if they will fail.
+      #
+      # @return [Boolean]
+      def feature_table_exists?
+        Feature::FlipperFeature.table_exists?
+      rescue
+        false
+      end
     end
   end
 end