Add an option database_type

lib/closure_tree/has_closure_tree.rb

@@ -11,7 +11,8 @@ def has_closure_tree(options = {})
  :dont_order_roots,
  :numeric_order,
  :touch,
- :with_advisory_lock
+ :with_advisory_lock,
+ :database_type
  )
 
  class_attribute :_ct

lib/closure_tree/numeric_order_support.rb

@@ -12,6 +12,17 @@ def self.adapter_for_connection(connection)
  end
  end
 
+ def self.adapter_for_database_type(database_type)
+ case database_type
+ when :postgres
+ ::ClosureTree::NumericOrderSupport::PostgreSQLAdapter
+ when :mysql
+ ::ClosureTree::NumericOrderSupport::MysqlAdapter
+ else
+ ::ClosureTree::NumericOrderSupport::GenericAdapter
+ end
+ end
+
  module MysqlAdapter
  def reorder_with_parent_id(parent_id, minimum_sort_order_value = nil)
  return if parent_id.nil? && dont_order_roots

lib/closure_tree/support.rb

@@ -27,7 +27,8 @@ def initialize(model_class, options)
  }.merge(options)
  raise ArgumentError, "name_column can't be 'path'" if options[:name_column] == 'path'
  if order_is_numeric?
- extend NumericOrderSupport.adapter_for_connection(connection)
+ database_type = database_type_from_options || database_type_from_connection
+ extend NumericOrderSupport.adapter_for_database_type(database_type)
  end
  end
 
@@ -170,5 +171,16 @@ def create(model_class, attributes)
  def create!(model_class, attributes)
  create(model_class, attributes).tap { |ea| ea.save! }
  end
+
+ def database_type_from_connection
+ das = WithAdvisoryLock::DatabaseAdapterSupport.new(connection)
+ if das.postgresql?
+ :postgres
+ elsif das.mysql?
+ :mysql
+ else
+ :generic
+ end
+ end
  end
 end

lib/closure_tree/support_flags.rb

@@ -31,5 +31,9 @@ def has_inheritance_column?(hash = columns_hash)
  def has_name?
  model_class.new.attributes.include? options[:name_column]
  end
+
+ def database_type_from_options
+ options[:database_type]
+ end
  end
 end