From ac4c1c3b0adabecdb1217594fed16db32b27ee9e Mon Sep 17 00:00:00 2001
From: Sean Griffin <sean@thoughtbot.com>
Date: Tue, 20 May 2014 08:07:02 -0700
Subject: Use the generic type map object for mysql field lookups

---
 .../connection_adapters/mysql_adapter.rb           | 32 ++++++----------------
 .../lib/active_record/connection_adapters/type.rb  |  2 ++
 .../type/hash_lookup_type_map.rb                   | 15 ++++++++++
 .../connection_adapters/type/type_map_test.rb      | 13 +++++++++
 4 files changed, 39 insertions(+), 23 deletions(-)
 create mode 100644 activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb

diff --git a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
index acf4015672..8beb869ce2 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql_adapter.rb
@@ -297,23 +297,17 @@ module ActiveRecord
           end
         end
 
-        TYPES = {}
+        class << self
+          TYPES = ConnectionAdapters::Type::HashLookupTypeMap.new # :nodoc:
 
-        # Register an MySQL +type_id+ with a typecasting object in
-        # +type+.
-        def self.register_type(type_id, type)
-          TYPES[type_id] = type
-        end
-
-        def self.alias_type(new, old)
-          TYPES[new] = TYPES[old]
-        end
+          delegate :register_type, :alias_type, to: :TYPES
 
-        def self.find_type(field)
-          if field.type == Mysql::Field::TYPE_TINY && field.length > 1
-            TYPES[Mysql::Field::TYPE_LONG]
-          else
-            TYPES.fetch(field.type) { Type::Value.new }
+          def find_type(field)
+            if field.type == Mysql::Field::TYPE_TINY && field.length > 1
+              TYPES.lookup(Mysql::Field::TYPE_LONG)
+            else
+              TYPES.lookup(field.type)
+            end
           end
         end
 
@@ -322,18 +316,10 @@ module ActiveRecord
         alias_type Mysql::Field::TYPE_LONGLONG,   Mysql::Field::TYPE_LONG
         alias_type Mysql::Field::TYPE_NEWDECIMAL, Mysql::Field::TYPE_LONG
 
-        register_type Mysql::Field::TYPE_VAR_STRING, Type::Value.new
-        register_type Mysql::Field::TYPE_BLOB, Type::Value.new
         register_type Mysql::Field::TYPE_DATE, Type::Date.new
         register_type Mysql::Field::TYPE_DATETIME, Fields::DateTime.new
         register_type Mysql::Field::TYPE_TIME, Fields::Time.new
         register_type Mysql::Field::TYPE_FLOAT, Type::Float.new
-
-        Mysql::Field.constants.grep(/TYPE/).map { |class_name|
-          Mysql::Field.const_get class_name
-        }.reject { |const| TYPES.key? const }.each do |const|
-          register_type const, Type::Value.new
-        end
       end
 
       def initialize_type_map(m) # :nodoc:
diff --git a/activerecord/lib/active_record/connection_adapters/type.rb b/activerecord/lib/active_record/connection_adapters/type.rb
index fbc4cd7e32..f215266560 100644
--- a/activerecord/lib/active_record/connection_adapters/type.rb
+++ b/activerecord/lib/active_record/connection_adapters/type.rb
@@ -11,7 +11,9 @@ require 'active_record/connection_adapters/type/integer'
 require 'active_record/connection_adapters/type/string'
 require 'active_record/connection_adapters/type/text'
 require 'active_record/connection_adapters/type/time'
+
 require 'active_record/connection_adapters/type/type_map'
+require 'active_record/connection_adapters/type/hash_lookup_type_map'
 
 module ActiveRecord
   module ConnectionAdapters
diff --git a/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb b/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb
new file mode 100644
index 0000000000..828ada00a7
--- /dev/null
+++ b/activerecord/lib/active_record/connection_adapters/type/hash_lookup_type_map.rb
@@ -0,0 +1,15 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module Type
+      class HashLookupTypeMap < TypeMap # :nodoc:
+        def lookup(type)
+          @mapping.fetch(type, proc { default_value }).call(type)
+        end
+
+        def alias_type(type, alias_type)
+          register_type(type) { lookup(alias_type) }
+        end
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/connection_adapters/type/type_map_test.rb b/activerecord/test/cases/connection_adapters/type/type_map_test.rb
index 300c2ed225..4b4d9f6b0f 100644
--- a/activerecord/test/cases/connection_adapters/type/type_map_test.rb
+++ b/activerecord/test/cases/connection_adapters/type/type_map_test.rb
@@ -95,6 +95,19 @@ module ActiveRecord
             mapping.register_type(/only key/i)
           end
         end
+
+        def test_lookup_non_strings
+          mapping = HashLookupTypeMap.new
+
+          mapping.register_type(1, 'string')
+          mapping.register_type(2, 'int')
+          mapping.alias_type(3, 1)
+
+          assert_equal mapping.lookup(1), 'string'
+          assert_equal mapping.lookup(2), 'int'
+          assert_equal mapping.lookup(3), 'string'
+          assert_kind_of Type::Value, mapping.lookup(4)
+        end
       end
     end
   end
-- 
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