Remove SessionHash inheritance from Hash

Previous api provided by SessionHash was inconsistent. All methods
provided by Hash which were not rewritten in SessionHash were behaving
incorrectly when session was not loaded yet. For example, #replace, #each,
 #keep_if and many more. So by dropping Hash inheritance we provide
clean api with all methods working without regard to whether session was
loaded or not.

lib/rack/session/abstract/id.rb

@@ -20,20 +20,17 @@ module Abstract

      # SessionHash is responsible to lazily load the session from store.

      class SessionHash < Hash
      class SessionHash
        attr_writer :id

        def initialize(by, env)
          super()
          @by = by
          @env = env
          @loaded = false
          @id_loaded = false
        end

        def id
          return @id if @loaded or @id_loaded
          @id_loaded = true
          return @id if @loaded or instance_variable_defined?(:@id)
          @id = @by.send(:extract_session_id, @env)
        end

@@ -43,24 +40,26 @@ def options

        def [](key)
          load_for_read!
          super(key.to_s)
          @data[key.to_s]
        end
        alias :fetch :[]

        def has_key?(key)
          load_for_read!
          super(key.to_s)
          @data.has_key?(key.to_s)
        end
        alias :key? :has_key?
        alias :include? :has_key?

        def []=(key, value)
          load_for_write!
          super(key.to_s, value)
          @data[key.to_s] = value
        end
        alias :store :[]=

        def clear
          load_for_write!
          super
          @data.clear
        end

        def destroy
@@ -70,29 +69,36 @@ def destroy

        def to_hash
          load_for_read!
          Hash[self].delete_if { |k,v| v.nil? }
          @data.dup
        end

        def update(hash)
          load_for_write!
          super(stringify_keys(hash))
          @data.update(stringify_keys(hash))
        end
        alias :merge! :update

        def replace(hash)
          load_for_write!
          @data.replace(stringify_keys(hash))
        end

        def delete(key)
          load_for_write!
          super(key.to_s)
          @data.delete(key.to_s)
        end

        def inspect
          if loaded?
            super
            @data.inspect
          else
            "#<#{self.class}:0x#{self.object_id.to_s(16)} not yet loaded>"
          end
        end

        def exists?
          return @exists if instance_variable_defined?(:@exists)
          @data = {}
          @exists = @by.send(:session_exists?, @env)
        end

@@ -102,7 +108,7 @@ def loaded?

        def empty?
          load_for_read!
          super
          @data.empty?
        end

      private
@@ -117,7 +123,7 @@ def load_for_write!

        def load!
          @id, session = @by.send(:load_session, @env)
          replace(stringify_keys(session))
          @data = stringify_keys(session)
          @loaded = true
        end

@@ -297,7 +303,6 @@ def commit_session(env, status, headers, body)
          options = session.options

          if options[:drop] || options[:renew]
            # if there is no session.id then we have nothing to destroy?!
            session_id = destroy_session(env, session.id || generate_sid, options)
            return [status, headers, body] unless session_id
          end
@@ -306,9 +311,9 @@ def commit_session(env, status, headers, body)

          session.send(:load!) unless loaded_session?(session)
          session_id ||= session.id || generate_sid
          session = session.to_hash
          session_data = session.to_hash.delete_if { |k,v| v.nil? }

          if not data = set_session(env, session_id, session, options)
          if not data = set_session(env, session_id, session_data, options)
            env["rack.errors"].puts("Warning! #{self.class.name} failed to save session. Content dropped.")
          elsif options[:defer] and not options[:renew]
            env["rack.errors"].puts("Defering cookie for #{session_id}") if $VERBOSE