Move the construction of `WhereClause` objects out of `Relation`

Yes, I know, I called it a factory so I'm basically the worst person
ever who loves Java and worships the Gang of Four.

2 files changed, 42 insertions, 14 deletions

diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index 9a636bc527..863d7bb1aa 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -2,6 +2,7 @@ require 'active_support/core_ext/array/wrap'
 require 'active_support/core_ext/string/filters'
 require 'active_model/forbidden_attributes_protection'
 require "active_record/relation/where_clause"
+require "active_record/relation/where_clause_factory"
 
 module ActiveRecord
   module QueryMethods
@@ -969,20 +970,9 @@ module ActiveRecord
     end
 
     def build_where(opts, other = [])
-      case opts
-      when String, Array
-        [@klass.send(:sanitize_sql, other.empty? ? opts : ([opts] + other))]
-      when Hash
-        opts = predicate_builder.resolve_column_aliases(opts)
-        opts = @klass.send(:expand_hash_conditions_for_aggregates, opts)
-
-        attributes, bind_values = predicate_builder.create_binds(opts)
-        self.bind_values += bind_values
-
-        predicate_builder.build_from_hash(attributes)
-      else
-        [opts]
-      end
+      where_clause = where_clause_factory.build(opts, other)
+      self.bind_values += where_clause.binds
+      where_clause.parts
     end
 
     def association_for_table(table_name)
@@ -1151,5 +1141,9 @@ module ActiveRecord
     def new_where_clause
       Relation::WhereClause.empty
     end
+
+    def where_clause_factory
+      @where_clause_factory ||= Relation::WhereClauseFactory.new(klass, predicate_builder)
+    end
   end
 end
diff --git a/activerecord/lib/active_record/relation/where_clause_factory.rb b/activerecord/lib/active_record/relation/where_clause_factory.rb
new file mode 100644
index 0000000000..0430922be3
--- /dev/null
+++ b/activerecord/lib/active_record/relation/where_clause_factory.rb
@@ -0,0 +1,34 @@
+module ActiveRecord
+  class Relation
+    class WhereClauseFactory
+      def initialize(klass, predicate_builder)
+        @klass = klass
+        @predicate_builder = predicate_builder
+      end
+
+      def build(opts, other)
+        binds = []
+
+        case opts
+        when String, Array
+          parts = [klass.send(:sanitize_sql, other.empty? ? opts : ([opts] + other))]
+        when Hash
+          attributes = predicate_builder.resolve_column_aliases(opts)
+          attributes = klass.send(:expand_hash_conditions_for_aggregates, attributes)
+
+          attributes, binds = predicate_builder.create_binds(attributes)
+
+          parts = predicate_builder.build_from_hash(attributes)
+        else
+          parts = [opts]
+        end
+
+        WhereClause.new(parts, binds)
+      end
+
+      protected
+
+      attr_reader :klass, :predicate_builder
+    end
+  end
+end