From 83c1be1ea087db77d2eb4b542ef84e84b59470e5 Mon Sep 17 00:00:00 2001
From: Kevin Deisz <kevin.deisz@gmail.com>
Date: Thu, 2 Feb 2017 17:17:52 -0500
Subject: [PATCH] Extract out registry

---
 .../connection_adapters/odbc_adapter.rb       |  1 +
 lib/odbc_adapter.rb                           | 15 ------
 lib/odbc_adapter/dbms.rb                      | 22 +-------
 lib/odbc_adapter/registry.rb                  | 51 +++++++++++++++++++
 test/registry_test.rb                         | 22 ++++++++
 5 files changed, 75 insertions(+), 36 deletions(-)
 create mode 100644 lib/odbc_adapter/registry.rb
 create mode 100644 test/registry_test.rb

diff --git a/lib/active_record/connection_adapters/odbc_adapter.rb b/lib/active_record/connection_adapters/odbc_adapter.rb
index fdf68026..60c18e45 100644
--- a/lib/active_record/connection_adapters/odbc_adapter.rb
+++ b/lib/active_record/connection_adapters/odbc_adapter.rb
@@ -11,6 +11,7 @@
 require 'odbc_adapter/column'
 require 'odbc_adapter/column_metadata'
 require 'odbc_adapter/dbms'
+require 'odbc_adapter/registry'
 require 'odbc_adapter/type_caster'
 require 'odbc_adapter/version'
 
diff --git a/lib/odbc_adapter.rb b/lib/odbc_adapter.rb
index 3dfa3294..194fb562 100644
--- a/lib/odbc_adapter.rb
+++ b/lib/odbc_adapter.rb
@@ -1,17 +1,2 @@
 # Requiring with this pattern to mirror ActiveRecord
 require 'active_record/connection_adapters/odbc_adapter'
-
-module ODBCAdapter
-  class << self
-    def dbms_registry
-      @dbms_registry ||= {
-        /my.*sql/i => :MySQL,
-        /postgres/i => :PostgreSQL
-      }
-    end
-
-    def register(pattern, superclass = Object, &block)
-      dbms_registry[pattern] = Class.new(superclass, &block)
-    end
-  end
-end
diff --git a/lib/odbc_adapter/dbms.rb b/lib/odbc_adapter/dbms.rb
index d5ede8c9..3df2bb42 100644
--- a/lib/odbc_adapter/dbms.rb
+++ b/lib/odbc_adapter/dbms.rb
@@ -20,31 +20,11 @@ def initialize(connection)
     end
 
     def adapter_class
-      return adapter unless adapter.is_a?(Symbol)
-      require "odbc_adapter/adapters/#{adapter.downcase}_odbc_adapter"
-      Adapters.const_get(:"#{adapter}ODBCAdapter")
+      ODBCAdapter.adapter_for(field_for(ODBC::SQL_DBMS_NAME))
     end
 
     def field_for(field)
       fields[field]
     end
-
-    private
-
-    # Maps a DBMS name to a symbol
-    # Different ODBC drivers might return different names for the same DBMS
-    def adapter
-      @adapter ||=
-        begin
-          reported = field_for(ODBC::SQL_DBMS_NAME).downcase.gsub(/\s/, '')
-          found =
-            ODBCAdapter.dbms_registry.detect do |pattern, adapter|
-              adapter if reported =~ pattern
-            end
-
-          raise ArgumentError, "ODBCAdapter: Unsupported database (#{reported})" if found.nil?
-          found.last
-        end
-    end
   end
 end
diff --git a/lib/odbc_adapter/registry.rb b/lib/odbc_adapter/registry.rb
new file mode 100644
index 00000000..39170378
--- /dev/null
+++ b/lib/odbc_adapter/registry.rb
@@ -0,0 +1,51 @@
+module ODBCAdapter
+  class Registry
+    attr_reader :dbs
+
+    def initialize
+      @dbs = {
+        /my.*sql/i  => :MySQL,
+        /postgres/i => :PostgreSQL
+      }
+    end
+
+    def adapter_for(reported_name)
+      reported_name = reported_name.downcase.gsub(/\s/, '')
+      found =
+        dbs.detect do |pattern, adapter|
+          adapter if reported_name =~ pattern
+        end
+
+      raise ArgumentError, "ODBCAdapter: Unsupported database (#{reported_name})" if found.nil?
+      normalize_adapter(found.last)
+    end
+
+    def register(pattern, superclass = Object, &block)
+      dbs[pattern] = Class.new(superclass, &block)
+    end
+
+    private
+
+    def normalize_adapter(adapter)
+      return adapter unless adapter.is_a?(Symbol)
+      require "odbc_adapter/adapters/#{adapter.downcase}_odbc_adapter"
+      Adapters.const_get(:"#{adapter}ODBCAdapter")
+    end
+  end
+
+  class << self
+    def adapter_for(reported_name)
+      registry.adapter_for(reported_name)
+    end
+
+    def register(pattern, superclass = Object, &block)
+      registry.register(pattern, superclass, &block)
+    end
+
+    private
+
+    def registry
+      @registry ||= Registry.new
+    end
+  end
+end
diff --git a/test/registry_test.rb b/test/registry_test.rb
new file mode 100644
index 00000000..b829fd03
--- /dev/null
+++ b/test/registry_test.rb
@@ -0,0 +1,22 @@
+require 'test_helper'
+
+class RegistryTest < Minitest::Test
+  def test_register
+    registry = ODBCAdapter::Registry.new
+
+    require File.join('odbc_adapter', 'adapters', 'mysql_odbc_adapter')
+    registry.register(/foobar/, ODBCAdapter::Adapters::MySQLODBCAdapter) do
+      def initialize
+      end
+
+      def quoted_true
+        'foobar'
+      end
+    end
+
+    adapter = registry.adapter_for('Foo Bar')
+    assert_kind_of Class, adapter
+    assert_equal ODBCAdapter::Adapters::MySQLODBCAdapter, adapter.superclass
+    assert_equal 'foobar', adapter.new.quoted_true
+  end
+end