Remove most PG specific type subclasses

The latest version of the PG gem can actually convert the primitives for
us in C code, which gives a pretty substantial speed up. A few cases
were only there to add the `infinity` method, which I just put on the
range type (which is the only place it was used). Floats also needed to
parse `Infinity` and `NaN`, but it felt reasonable enough to put that on
the generic form.

Gemfile

@@ -85,7 +85,7 @@ platforms :ruby do
   gem 'sqlite3', '~> 1.3.6'
 
   group :db do
-    gem 'pg', '>= 0.15.0'
+    gem 'pg', '>= 0.18.0'
     gem 'mysql', '>= 2.9.0'
     gem 'mysql2', '>= 0.3.13'
   end

activerecord/lib/active_record/connection_adapters/postgresql/oid.rb

-require 'active_record/connection_adapters/postgresql/oid/infinity'
-
 require 'active_record/connection_adapters/postgresql/oid/array'
 require 'active_record/connection_adapters/postgresql/oid/bit'
 require 'active_record/connection_adapters/postgresql/oid/bit_varying'
 require 'active_record/connection_adapters/postgresql/oid/bytea'
 require 'active_record/connection_adapters/postgresql/oid/cidr'
-require 'active_record/connection_adapters/postgresql/oid/date'
 require 'active_record/connection_adapters/postgresql/oid/date_time'
 require 'active_record/connection_adapters/postgresql/oid/decimal'
 require 'active_record/connection_adapters/postgresql/oid/enum'
-require 'active_record/connection_adapters/postgresql/oid/float'
 require 'active_record/connection_adapters/postgresql/oid/hstore'
 require 'active_record/connection_adapters/postgresql/oid/inet'
-require 'active_record/connection_adapters/postgresql/oid/integer'
 require 'active_record/connection_adapters/postgresql/oid/json'
 require 'active_record/connection_adapters/postgresql/oid/jsonb'
 require 'active_record/connection_adapters/postgresql/oid/money'
 require 'active_record/connection_adapters/postgresql/oid/point'
 require 'active_record/connection_adapters/postgresql/oid/range'
 require 'active_record/connection_adapters/postgresql/oid/specialized_string'
-require 'active_record/connection_adapters/postgresql/oid/time'
 require 'active_record/connection_adapters/postgresql/oid/uuid'
 require 'active_record/connection_adapters/postgresql/oid/vector'
 require 'active_record/connection_adapters/postgresql/oid/xml'

activerecord/lib/active_record/connection_adapters/postgresql/oid/date.rb

-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module OID # :nodoc:
-        class Date < Type::Date # :nodoc:
-          include Infinity
-        end
-      end
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/postgresql/oid/date_time.rb

@@ -3,8 +3,6 @@ module ConnectionAdapters
     module PostgreSQL
       module OID # :nodoc:
         class DateTime < Type::DateTime # :nodoc:
-          include Infinity
-
           def cast_value(value)
             if value.is_a?(::String)
               case value

activerecord/lib/active_record/connection_adapters/postgresql/oid/float.rb

-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module OID # :nodoc:
-        class Float < Type::Float # :nodoc:
-          include Infinity
-
-          def cast_value(value)
-            case value
-            when ::Float then     value
-            when 'Infinity' then  ::Float::INFINITY
-            when '-Infinity' then -::Float::INFINITY
-            when 'NaN' then       ::Float::NAN
-            else                  value.to_f
-            end
-          end
-        end
-      end
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/postgresql/oid/infinity.rb

-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module OID # :nodoc:
-        module Infinity # :nodoc:
-          def infinity(options = {})
-            options[:negative] ? -::Float::INFINITY : ::Float::INFINITY
-          end
-        end
-      end
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/postgresql/oid/integer.rb

-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module OID # :nodoc:
-        class Integer < Type::Integer # :nodoc:
-          include Infinity
-        end
-      end
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/postgresql/oid/money.rb

@@ -3,8 +3,6 @@ module ConnectionAdapters
     module PostgreSQL
       module OID # :nodoc:
         class Money < Type::Decimal # :nodoc:
-          include Infinity
-
           class_attribute :precision
 
           def type

activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb

@@ -59,13 +59,23 @@ def type_cast_single_for_database(value)
           def extract_bounds(value)
             from, to = value[1..-2].split(',')
             {
-              from:          (value[1] == ',' || from == '-infinity') ? @subtype.infinity(negative: true) : from,
-              to:            (value[-2] == ',' || to == 'infinity') ? @subtype.infinity : to,
+              from:          (value[1] == ',' || from == '-infinity') ? infinity(negative: true) : from,
+              to:            (value[-2] == ',' || to == 'infinity') ? infinity : to,
               exclude_start: (value[0] == '('),
               exclude_end:   (value[-1] == ')')
             }
           end
 
+          def infinity(negative: false)
+            if subtype.respond_to?(:infinity)
+              subtype.infinity(negative: negative)
+            elsif negative
+              -::Float::INFINITY
+            else
+              ::Float::INFINITY
+            end
+          end
+
           def infinity?(value)
             value.respond_to?(:infinite?) && value.infinite?
           end

activerecord/lib/active_record/connection_adapters/postgresql/oid/time.rb

-module ActiveRecord
-  module ConnectionAdapters
-    module PostgreSQL
-      module OID # :nodoc:
-        class Time < Type::Time # :nodoc:
-          include Infinity
-        end
-      end
-    end
-  end
-end

activerecord/lib/active_record/connection_adapters/postgresql/oid/type_map_initializer.rb

@@ -8,8 +8,9 @@ module OID # :nodoc:
         #   - Type is an OID::Type object.
         # This class has side effects on the +store+ passed during initialization.
         class TypeMapInitializer # :nodoc:
-          def initialize(store)
+          def initialize(store, run_complex_types = true)
             @store = store
+            @run_complex_types = run_complex_types
           end
 
           def run(records)

activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb

@@ -127,18 +127,15 @@ def type_classes_with_standard_constructor
             bit_varying: OID::BitVarying,
             binary: OID::Bytea,
             cidr: OID::Cidr,
-            date: OID::Date,
             date_time: OID::DateTime,
             decimal: OID::Decimal,
             enum: OID::Enum,
-            float: OID::Float,
             hstore: OID::Hstore,
             inet: OID::Inet,
             json: OID::Json,
             jsonb: OID::Jsonb,
             money: OID::Money,
             point: OID::Point,
-            time: OID::Time,
             uuid: OID::Uuid,
             vector: OID::Vector,
             xml: OID::Xml,

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -255,6 +255,8 @@ def initialize(connection, logger, connection_parameters, config)
         @table_alias_length = nil
 
         connect
+        add_pg_decoders
+
         @statements = StatementPool.new @connection,
                                         self.class.type_cast_config_to_integer(config.fetch(:statement_limit) { 1000 })
 
@@ -459,11 +461,11 @@ def get_oid_type(oid, fmod, column_name, sql_type = '') # :nodoc:
         end
 
         def initialize_type_map(m) # :nodoc:
-          register_class_with_limit m, 'int2', OID::Integer
-          register_class_with_limit m, 'int4', OID::Integer
-          register_class_with_limit m, 'int8', OID::Integer
+          register_class_with_limit m, 'int2', Type::Integer
+          register_class_with_limit m, 'int4', Type::Integer
+          register_class_with_limit m, 'int8', Type::Integer
           m.alias_type 'oid', 'int2'
-          m.register_type 'float4', OID::Float.new
+          m.register_type 'float4', Type::Float.new
           m.alias_type 'float8', 'float4'
           m.register_type 'text', Type::Text.new
           register_class_with_limit m, 'varchar', Type::String
@@ -474,8 +476,8 @@ def initialize_type_map(m) # :nodoc:
           register_class_with_limit m, 'bit', OID::Bit
           register_class_with_limit m, 'varbit', OID::BitVarying
           m.alias_type 'timestamptz', 'timestamp'
-          m.register_type 'date', OID::Date.new
-          m.register_type 'time', OID::Time.new
+          m.register_type 'date', Type::Date.new
+          m.register_type 'time', Type::Time.new
 
           m.register_type 'money', OID::Money.new
           m.register_type 'bytea', OID::Bytea.new
@@ -780,6 +782,36 @@ def can_perform_case_insensitive_comparison_for?(column)
             end
           end
         end
+
+        def add_pg_decoders
+          coders_by_name = {
+            'int2' => PG::TextDecoder::Integer,
+            'int4' => PG::TextDecoder::Integer,
+            'int8' => PG::TextDecoder::Integer,
+            'oid' => PG::TextDecoder::Integer,
+            'float4' => PG::TextDecoder::Float,
+            'float8' => PG::TextDecoder::Float,
+            'bool' => PG::TextDecoder::Boolean,
+          }
+          query = <<-SQL
+            SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, t.typtype, t.typbasetype
+            FROM pg_type as t
+          SQL
+          coders = execute_and_clear(query, "SCHEMA", []) do |result|
+            result
+              .map { |row| construct_coder(row, coders_by_name['typname']) }
+              .compact
+          end
+
+          map = PG::TypeMapByOid.new
+          coders.each { |coder| map.add_coder(coder) }
+          @connection.type_map_for_results = map
+        end
+
+        def construct_coder(row, coder_class)
+          return unless coder_class
+          coder_class.new(oid: row['oid'], name: row['typname'])
+        end
     end
   end
 end

activerecord/lib/active_record/type/float.rb

@@ -12,7 +12,13 @@ def type
       private
 
       def cast_value(value)
-        value.to_f
+        case value
+        when ::Float then value
+        when "Infinity" then ::Float::INFINITY
+        when "-Infinity" then -::Float::INFINITY
+        when "NaN" then ::Float::NAN
+        else value.to_f
+        end
       end
     end
   end