dynamically define PostgreSQL OID range types.

This gets AR working with custom defined range types. It also
removes the need for subtype specific branches in `OID::Range`.

This expands the interface of all `OID` types with the `infinity` method.
It's responsible to provide a value for positive and negative infinity.

1 files changed, 23 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 36c7462419..d1fb132b60 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -785,18 +785,29 @@ module ActiveRecord
         end
 
         def initialize_type_map(type_map)
-          result = execute('SELECT oid, typname, typelem, typdelim, typinput FROM pg_type', 'SCHEMA')
-          leaves, nodes = result.partition { |row| row['typelem'] == '0' }
+          if supports_ranges?
+            result = execute(<<-SQL, 'SCHEMA')
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput, r.rngsubtype
+              FROM pg_type as t
+              LEFT JOIN pg_range as r ON oid = rngtypid
+            SQL
+          else
+            result = execute(<<-SQL, 'SCHEMA')
+              SELECT t.oid, t.typname, t.typelem, t.typdelim, t.typinput
+              FROM pg_type as t
+            SQL
+          end
+          ranges, nodes = result.partition { |row| row['typinput'] == 'range_in' }
+          leaves, nodes = nodes.partition { |row| row['typelem'] == '0' }
+          arrays, nodes = nodes.partition { |row| row['typinput'] == 'array_in' }
 
-          # populate the leaf nodes
+          # populate the base types
           leaves.find_all { |row| OID.registered_type? row['typname'] }.each do |row|
             type_map[row['oid'].to_i] = OID::NAMES[row['typname']]
           end
 
           records_by_oid = result.group_by { |row| row['oid'] }
 
-          arrays, nodes = nodes.partition { |row| row['typinput'] == 'array_in' }
-
           # populate composite types
           nodes.each do |row|
             add_oid row, records_by_oid, type_map
@@ -807,6 +818,13 @@ module ActiveRecord
             array = OID::Array.new  type_map[row['typelem'].to_i]
             type_map[row['oid'].to_i] = array
           end
+
+          # populate range types
+          ranges.find_all { |row| type_map.key? row['rngsubtype'].to_i }.each do |row|
+            subtype = type_map[row['rngsubtype'].to_i]
+            range = OID::Range.new type_map[row['rngsubtype'].to_i]
+            type_map[row['oid'].to_i] = range
+          end
         end
 
         FEATURE_NOT_SUPPORTED = "0A000" #:nodoc: