Move resource limit tracking to its own class

lib/liquid/resource_limits.rb

@@ -0,0 +1,40 @@
+module Liquid
+  class ResourceLimits
+    attr_accessor :render_length, :render_score, :assign_score,
+                  :render_length_limit, :render_score_limit, :assign_score_limit
+
+    def initialize(limits)
+      @render_length_limit = limits[:render_length_limit]
+      @render_score_limit = limits[:render_score_limit]
+      @assign_score_limit = limits[:assign_score_limit]
+
+      # render_length is assigned by BlockBody
+      # @render_length = 0
+      @render_score = 0
+      @assign_score = 0
+    end
+
+    def reached?
+      (@render_length_limit && @render_length > @render_length_limit) ||
+      (@render_score_limit  && @render_score  > @render_score_limit ) ||
+      (@assign_score_limit  && @assign_score  > @assign_score_limit )
+    end
+
+    def increment_render_length(obj)
+      @render_length += increment_for(obj)
+    end
+
+    def increment_render_score(obj)
+      @render_score += increment_for(obj)
+    end
+
+    def increment_assign_score(obj)
+      @assign_score += increment_for(obj)
+    end
+
+    private
+    def increment_for(obj)
+      obj.instance_of?(String) || obj.instance_of?(Array) || obj.instance_of?(Hash) ? obj.length : 1
+    end
+  end
+end