pg, re-introduce PostgreSQL::Utils to unify schema/table extraction.

Partial revert of c0bfc3f

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

@@ -150,13 +150,11 @@ def quote_string(s) #:nodoc:
         # - "schema.name".table_name
         # - "schema.name"."table.name"
         def quote_table_name(name)
-          schema, name_part = extract_pg_identifier_from_name(name.to_s)
-
-          unless name_part
-            quote_column_name(schema)
+          schema, table = Utils.extract_schema_and_table(name.to_s)
+          if schema
+            "#{quote_column_name(schema)}.#{quote_column_name(table)}"
           else
-            table_name, name_part = extract_pg_identifier_from_name(name_part)
-            "#{quote_column_name(schema)}.#{quote_column_name(table_name)}"
+            quote_column_name(table)
           end
         end
 

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

@@ -97,7 +97,7 @@ def tables(name = nil)
         # If the schema is not specified as part of +name+ then it will only find tables within
         # the current schema search path (regardless of permissions to access tables in other schemas)
         def table_exists?(name)
-          schema, table = extract_schema_and_table(name.to_s)
+          schema, table = Utils.extract_schema_and_table(name.to_s)
           return false unless table
 
           exec_query(<<-SQL, 'SCHEMA').rows.first[0].to_i > 0
@@ -488,23 +488,6 @@ def columns_for_distinct(columns, orders) #:nodoc:
 
           [super, *order_columns].join(', ')
         end
-
-        private
-
-        # Returns an array of <tt>[schema_name, table_name]</tt> extracted from +name+.
-        # +schema_name+ is nil if not specified in +name+.
-        # +schema_name+ and +table_name+ exclude surrounding quotes (regardless of whether provided in +name+)
-        # +name+ supports the range of schema/table references understood by PostgreSQL, for example:
-        #
-        # * <tt>table_name</tt>
-        # * <tt>"table.name"</tt>
-        # * <tt>schema_name.table_name</tt>
-        # * <tt>schema_name."table.name"</tt>
-        # * <tt>"schema.name"."table name"</tt>
-        def extract_schema_and_table(name)
-          table, schema = name.scan(/[^".\s]+|"[^"]*"/)[0..1].collect{|m| m.gsub(/(^"|"$)/,'') }.reverse
-          [schema, table]
-        end
       end
     end
   end

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

@@ -0,0 +1,25 @@
+module ActiveRecord
+  module ConnectionAdapters
+    module PostgreSQL
+      module Utils # :nodoc:
+        extend self
+
+        # Returns an array of <tt>[schema_name, table_name]</tt> extracted from +name+.
+        # +schema_name+ is nil if not specified in +name+.
+        # +schema_name+ and +table_name+ exclude surrounding quotes (regardless of whether provided in +name+)
+        # +name+ supports the range of schema/table references understood by PostgreSQL, for example:
+        #
+        # * <tt>table_name</tt>
+        # * <tt>"table.name"</tt>
+        # * <tt>schema_name.table_name</tt>
+        # * <tt>schema_name."table.name"</tt>
+        # * <tt>"schema_name".table_name</tt>
+        # * <tt>"schema.name"."table name"</tt>
+        def extract_schema_and_table(name)
+          table, schema = name.scan(/[^".\s]+|"[^"]*"/)[0..1].collect{|m| m.gsub(/(^"|"$)/,'') }.reverse
+          [schema, table]
+        end
+      end
+    end
+  end
+end

activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -1,6 +1,7 @@
 require 'active_record/connection_adapters/abstract_adapter'
 require 'active_record/connection_adapters/statement_pool'
 
+require 'active_record/connection_adapters/postgresql/utils'
 require 'active_record/connection_adapters/postgresql/column'
 require 'active_record/connection_adapters/postgresql/oid'
 require 'active_record/connection_adapters/postgresql/quoting'

activerecord/test/cases/adapters/postgresql/schema_test.rb

@@ -352,21 +352,6 @@ def test_schema_exists?
     end
   end
 
-  def test_extract_schema_and_table
-    {
-      %(table_name)            => [nil,'table_name'],
-      %("table.name")          => [nil,'table.name'],
-      %(schema.table_name)     => %w{schema table_name},
-      %("schema".table_name)   => %w{schema table_name},
-      %(schema."table_name")   => %w{schema table_name},
-      %("schema"."table_name") => %w{schema table_name},
-      %("even spaces".table)   => ['even spaces','table'],
-      %(schema."table.name")   => ['schema', 'table.name']
-    }.each do |given, expect|
-      assert_equal expect, @connection.send(:extract_schema_and_table, given)
-    end
-  end
-
   private
     def columns(table_name)
       @connection.send(:column_definitions, table_name).map do |name, type, default|

activerecord/test/cases/adapters/postgresql/utils_test.rb

@@ -0,0 +1,20 @@
+require 'cases/helper'
+
+class PostgreSQLUtilsTest < ActiveSupport::TestCase
+  include ActiveRecord::ConnectionAdapters::PostgreSQL::Utils
+
+  def test_extract_schema_and_table
+    {
+      %(table_name)            => [nil,'table_name'],
+      %("table.name")          => [nil,'table.name'],
+      %(schema.table_name)     => %w{schema table_name},
+      %("schema".table_name)   => %w{schema table_name},
+      %(schema."table_name")   => %w{schema table_name},
+      %("schema"."table_name") => %w{schema table_name},
+      %("even spaces".table)   => ['even spaces','table'],
+      %(schema."table.name")   => ['schema', 'table.name']
+    }.each do |given, expect|
+      assert_equal expect, extract_schema_and_table(given)
+    end
+  end
+end