From 8c7900f17b1019314712616f5362427ef9ac686b Mon Sep 17 00:00:00 2001
From: Holger Just <hello@holgerjust.de>
Date: Sat, 5 Aug 2017 15:47:17 +0200
Subject: [PATCH] Refactor: extract checks in FilterChain

---
 lib/rackstash/filter_chain.rb | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/lib/rackstash/filter_chain.rb b/lib/rackstash/filter_chain.rb
index f3e6a26..3eca5c0 100644
--- a/lib/rackstash/filter_chain.rb
+++ b/lib/rackstash/filter_chain.rb
@@ -63,7 +63,7 @@ module Rackstash
     # @param filter [#call, nil] the filter to set at `index`
     # @return [#call] the given `filter`
     def []=(index, filter)
-      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+      filter = build_filter(filter)
 
       synchronize do
         id = index_at(index)
@@ -86,8 +86,7 @@ module Rackstash
     # @raise [TypeError] if the given filter is not callable
     # @return [self]
     def append(filter = nil, &block)
-      filter ||= block
-      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+      filter = build_filter(filter || block)
 
       synchronize do
         @filters.push filter
@@ -180,8 +179,7 @@ module Rackstash
     # @raise [ArgumentError] if the existing filter could not be found
     # @return [self]
     def insert_after(index, filter = nil, &block)
-      filter ||= block
-      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+      filter = build_filter(filter || block)
 
       synchronize do
         id = index_at(index)
@@ -210,8 +208,7 @@ module Rackstash
     # @raise [ArgumentError] if the existing filter could not be found
     # @return [self]
     def insert_before(index, filter = nil, &block)
-      filter ||= block
-      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+      filter = build_filter(filter || block)
 
       synchronize do
         id = index_at(index)
@@ -250,8 +247,7 @@ module Rackstash
     # @raise [TypeError] if the given filter is not callable
     # @return [self]
     def unshift(filter = nil, &block)
-      filter ||= block
-      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+      filter = build_filter(filter || block)
 
       synchronize do
         @filters.unshift filter
@@ -295,5 +291,11 @@ module Rackstash
         @filters.index { |filter| filter == index }
       end
     end
+
+    def build_filter(filter)
+      raise TypeError, 'must provide a filter' unless filter.respond_to?(:call)
+
+      filter
+    end
   end
 end