Add option (true by default) to generate reader methods for each attribute of a record to avoid the overhead of calling method missing. In partial fullfilment of #1236.

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@2483 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

7 files changed, 152 insertions, 59 deletions

diff --git a/activerecord/CHANGELOG b/activerecord/CHANGELOG
index 7100989b1e..d38ac39282 100644
--- a/activerecord/CHANGELOG
+++ b/activerecord/CHANGELOG
@@ -1,5 +1,7 @@
 *SVN*
 
+* Add option (true by default) to generate reader methods for each attribute of a record to avoid the overhead of calling method missing. In partial fullfilment of #1236. [skaes@web.de]
+
 * Add convenience predicate methods on Column class. In partial fullfilment of #1236. [skaes@web.de]
 
 * Raise errors when invalid hash keys are passed to ActiveRecord::Base.find. #2363  [Chad Fowler <chad@chadfowler.com>, Nicholas Seckar]
diff --git a/activerecord/lib/active_record/base.rb b/activerecord/lib/active_record/base.rb
index f6219a5a98..72b0164047 100755
--- a/activerecord/lib/active_record/base.rb
+++ b/activerecord/lib/active_record/base.rb
@@ -300,6 +300,13 @@ module ActiveRecord #:nodoc:
     cattr_accessor :threaded_connections
     @@threaded_connections = true
 
+    # Determines whether to speed up access by generating optimized reader
+    # methods to avoid expensive calls to method_missing when accessing
+    # attributes by name. You might want to set this to false in development
+    # mode, because the methods would be regenerated on each request.
+    cattr_accessor :generate_read_methods
+    @@generate_read_methods = true
+
     class << self # Class methods
       # Find operates with three different retreval approaches:
       #
@@ -683,9 +690,16 @@ module ActiveRecord #:nodoc:
         end
       end
 
+    
+      # Contains the names of the generated reader methods.
+      def read_methods
+        @read_methods ||= {}
+      end
+      
       # Resets all the cached information about columns, which will cause they to be reloaded on the next request.
       def reset_column_information
-        @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = nil
+        read_methods.each_key {|name| undef_method(name)}
+        @column_names = @columns = @columns_hash = @content_columns = @dynamic_methods_hash = @read_methods = nil
       end
 
       def reset_column_information_and_inheritable_attributes_for_all_subclasses#:nodoc:
@@ -1016,7 +1030,10 @@ module ActiveRecord #:nodoc:
       # Every Active Record class must use "id" as their primary ID. This getter overwrites the native
       # id method, which isn't being used in this context.
       def id
-        read_attribute(self.class.primary_key)
+        attr_name = self.class.primary_key
+        column    = column_for_attribute(attr_name)
+        define_read_method(:id, attr_name, column) if self.class.generate_read_methods
+        (value = @attributes[attr_name]) && column.type_cast(value)
       end
 
       # Enables Active Record objects to be used as URL parameters in Action Pack automatically.
@@ -1267,6 +1284,7 @@ module ActiveRecord #:nodoc:
       def method_missing(method_id, *args, &block)
         method_name = method_id.to_s
         if @attributes.include?(method_name)
+          define_read_methods if self.class.read_methods.empty? && self.class.generate_read_methods
           read_attribute(method_name)
         elsif md = /(=|\?|_before_type_cast)$/.match(method_name)
           attribute_name, method_type = md.pre_match, md.to_s
@@ -1310,11 +1328,37 @@ module ActiveRecord #:nodoc:
         @attributes[attr_name]
       end
 
+      # Called on first read access to any given column and generates reader
+      # methods for all columns in the columns_hash if
+      # ActiveRecord::Base.generate_read_methods is set to true.
+      def define_read_methods
+        self.class.columns_hash.each do |name, column|
+          unless column.primary || self.class.serialized_attributes[name] || respond_to_without_attributes?(name)
+            define_read_method(name.to_sym, name, column)
+          end
+        end
+      end
+
+      # Define a column type specific reader method.
+      def define_read_method(symbol, attr_name, column)
+        cast_code = column.type_cast_code('v')
+        access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']"
+        body = access_code
+
+        # The following 3 lines behave exactly like method_missing if the
+        # attribute isn't present.
+        unless symbol == :id
+          body = body.insert(0, "raise NoMethodError, 'missing attribute: #{attr_name}', caller unless @attributes.has_key?('#{attr_name}'); ")
+        end
+        self.class.class_eval("def #{symbol}; #{body} end")
+
+        self.class.read_methods[attr_name] = true unless symbol == :id
+        logger.debug "Defined read method #{self.class.name}.#{symbol}" if logger
+      end
+
       # Returns true if the attribute is of a text column and marked for serialization.
       def unserializable_attribute?(attr_name, column)
-        if value = @attributes[attr_name]
-          [:text, :string].include?(column.send(:type)) && value.is_a?(String) && self.class.serialized_attributes[attr_name]
-        end
+        column.text? && self.class.serialized_attributes[attr_name]
       end
 
       # Returns the unserialized object of the attribute.
@@ -1332,12 +1376,21 @@ module ActiveRecord #:nodoc:
       # Updates the attribute identified by <tt>attr_name</tt> with the specified +value+. Empty strings for fixnum and float
       # columns are turned into nil.
       def write_attribute(attr_name, value)
-        @attributes[attr_name.to_s] = empty_string_for_number_column?(attr_name.to_s, value) ? nil : value
+        attr_name = attr_name.to_s
+        if (column = column_for_attribute(attr_name)) && column.number?
+          @attributes[attr_name] = convert_number_column_value(value)
+        else
+          @attributes[attr_name] = value
+        end
       end
 
-      def empty_string_for_number_column?(attr_name, value)
-        column = column_for_attribute(attr_name)
-        column && (column.klass == Fixnum || column.klass == Float) && value == ""
+      def convert_number_column_value(value)
+        case value
+          when FalseClass: 0
+          when TrueClass:  1
+          when '':         nil
+          else value
+        end
       end
 
       def query_attribute(attr_name)
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
index c7e7d83ca1..acfd0f0846 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/quoting.rb
@@ -7,8 +7,8 @@ module ActiveRecord
         case value
           when String
             if column && column.type == :binary
-              "'#{quote_string(column.string_to_binary(value))}'" # ' (for ruby-mode)
-            elsif column && [:integer, :float].include?(column.type)
+              "'#{quote_string(column.class.string_to_binary(value))}'" # ' (for ruby-mode)
+            elsif column && [:integer, :float].include?(column.type) 
               value.to_s
             else
               "'#{quote_string(value)}'" # ' (for ruby-mode)
@@ -48,4 +48,4 @@ module ActiveRecord
       end
     end
   end
-end
\ No newline at end of file
+end
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
index 1a633dcc00..d318e07750 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_definitions.rb
@@ -48,22 +48,38 @@ module ActiveRecord
 
       # Casts value (which is a String) to an appropriate instance.
       def type_cast(value)
-        if value.nil? then return nil end
+        return nil if value.nil?
         case type
           when :string    then value
           when :text      then value
           when :integer   then value.to_i rescue value ? 1 : 0
           when :float     then value.to_f
-          when :datetime  then string_to_time(value)
-          when :timestamp then string_to_time(value)
-          when :time      then string_to_dummy_time(value)
-          when :date      then string_to_date(value)
-          when :binary    then binary_to_string(value)
+          when :datetime  then self.class.string_to_time(value)
+          when :timestamp then self.class.string_to_time(value)
+          when :time      then self.class.string_to_dummy_time(value)
+          when :date      then self.class.string_to_date(value)
+          when :binary    then self.class.binary_to_string(value)
           when :boolean   then value == true or (value =~ /^t(rue)?$/i) == 0 or value.to_s == '1'
           else value
         end
       end
 
+      def type_cast_code(var_name)
+        case type
+          when :string    then nil
+          when :text      then nil
+          when :integer   then "(#{var_name}.to_i rescue #{var_name} ? 1 : 0)"
+          when :float     then "#{var_name}.to_f"
+          when :datetime  then "#{self.class.name}.string_to_time(#{var_name})"
+          when :timestamp then "#{self.class.name}.string_to_time(#{var_name})"
+          when :time      then "#{self.class.name}.string_to_dummy_time(#{var_name})"
+          when :date      then "#{self.class.name}.string_to_date(#{var_name})"
+          when :binary    then "#{self.class.name}.binary_to_string(#{var_name})"
+          when :boolean   then "(#{var_name} == true or (#{var_name} =~ /^t(?:true)?$/i) == 0 or #{var_name}.to_s == '1')"
+          else nil
+        end
+      end
+
       # Returns the human name of the column name.
       #
       # ===== Examples
@@ -73,38 +89,38 @@ module ActiveRecord
       end
 
       # Used to convert from Strings to BLOBs
-      def string_to_binary(value)
+      def self.string_to_binary(value)
         value
       end
 
       # Used to convert from BLOBs to Strings
-      def binary_to_string(value)
+      def self.binary_to_string(value)
         value
       end
 
-      private
-        def string_to_date(string)
-          return string unless string.is_a?(String)
-          date_array = ParseDate.parsedate(string)
-          # treat 0000-00-00 as nil
-          Date.new(date_array[0], date_array[1], date_array[2]) rescue nil
-        end
+      def self.string_to_date(string)
+        return string unless string.is_a?(String)
+        date_array = ParseDate.parsedate(string)
+        # treat 0000-00-00 as nil
+        Date.new(date_array[0], date_array[1], date_array[2]) rescue nil
+      end
 
-        def string_to_time(string)
-          return string unless string.is_a?(String)
-          time_array = ParseDate.parsedate(string)[0..5]
-          # treat 0000-00-00 00:00:00 as nil
-          Time.send(Base.default_timezone, *time_array) rescue nil
-        end
+      def self.string_to_time(string)
+        return string unless string.is_a?(String)
+        time_array = ParseDate.parsedate(string)[0..5]
+        # treat 0000-00-00 00:00:00 as nil
+        Time.send(Base.default_timezone, *time_array) rescue nil
+      end
 
-        def string_to_dummy_time(string)
-          return string unless string.is_a?(String)
-          time_array = ParseDate.parsedate(string)
-          # pad the resulting array with dummy date information
-          time_array[0] = 2000; time_array[1] = 1; time_array[2] = 1;
-          Time.send(Base.default_timezone, *time_array) rescue nil
-        end
+      def self.string_to_dummy_time(string)
+        return string unless string.is_a?(String)
+        time_array = ParseDate.parsedate(string)
+        # pad the resulting array with dummy date information
+        time_array[0] = 2000; time_array[1] = 1; time_array[2] = 1;
+        Time.send(Base.default_timezone, *time_array) rescue nil
+      end
 
+    private
         def extract_limit(sql_type)
           $1.to_i if sql_type =~ /\((.*)\)/
         end
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
index 8f2b6cda03..8f2129838b 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite_adapter.rb
@@ -62,22 +62,24 @@ module ActiveRecord
 
   module ConnectionAdapters #:nodoc:
     class SQLiteColumn < Column #:nodoc:
-      def string_to_binary(value)
-        value.gsub(/\0|\%/) do |b|
-          case b
-            when "\0" then "%00"
-            when "%"  then "%25"
-          end
-        end                
-      end
-      
-      def binary_to_string(value)
-        value.gsub(/%00|%25/) do |b|
-          case b
-            when "%00" then "\0"
-            when "%25" then "%"
-          end
-        end                
+      class <<  self
+        def string_to_binary(value)
+          value.gsub(/\0|\%/) do |b|
+            case b
+              when "\0" then "%00"
+              when "%"  then "%25"
+            end
+          end                
+        end
+        
+        def binary_to_string(value)
+          value.gsub(/%00|%25/) do |b|
+            case b
+              when "%00" then "\0"
+              when "%25" then "%"
+            end
+          end                
+        end
       end
     end
 
diff --git a/activerecord/lib/active_record/connection_adapters/sqlserver_adapter.rb b/activerecord/lib/active_record/connection_adapters/sqlserver_adapter.rb
index c1c9ae6f4b..253c8f4e88 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlserver_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlserver_adapter.rb
@@ -98,7 +98,7 @@ module ActiveRecord
 
       # These methods will only allow the adapter to insert binary data with a length of 7K or less
       # because of a SQL Server statement length policy.
-      def string_to_binary(value)
+      def self.string_to_binary(value)
         value.gsub(/(\r|\n|\0|\x1a)/) do
           case $1
             when "\r"   then  "%00"
@@ -109,7 +109,7 @@ module ActiveRecord
         end
       end
 
-      def binary_to_string(value)
+      def self.binary_to_string(value)
         value.gsub(/(%00|%01|%02|%03)/) do
           case $1
             when "%00"    then  "\r"
@@ -275,7 +275,7 @@ module ActiveRecord
         case value
           when String                
             if column && column.type == :binary
-              "'#{quote_string(column.string_to_binary(value))}'"
+              "'#{quote_string(column.class.string_to_binary(value))}'"
             else
               "'#{quote_string(value)}'"
             end
diff --git a/activerecord/test/base_test.rb b/activerecord/test/base_test.rb
index 35c608d809..aeb9ac970a 100755
--- a/activerecord/test/base_test.rb
+++ b/activerecord/test/base_test.rb
@@ -196,6 +196,19 @@ class BasicsTest < Test::Unit::TestCase
     assert !topic.approved?, "approved should be false"
   end
 
+  def test_reader_generation
+    Topic.find(:first).title
+    Firm.find(:first).name
+    Client.find(:first).name
+    if ActiveRecord::Base.generate_read_methods
+      assert_readers(Topic,  %w(type replies_count))
+      assert_readers(Firm,   %w(type))
+      assert_readers(Client, %w(type))
+    else
+      [Topic, Firm, Client].each {|klass| assert_equal klass.read_methods, {}}
+    end
+  end
+
   def test_preserving_date_objects
     # SQL Server doesn't have a separate column type just for dates, so all are returned as time
     if ActiveRecord::ConnectionAdapters.const_defined? :SQLServerAdapter
@@ -913,4 +926,11 @@ class BasicsTest < Test::Unit::TestCase
 
      assert_equal    firm.clients.collect{ |x| x.name }.sort, clients.collect{ |x| x.name }.sort
   end
+
+  private
+
+    def assert_readers(model, exceptions)
+      expected_readers = model.column_names - (model.serialized_attributes.keys + exceptions + ['id'])
+      assert_equal expected_readers.sort, model.read_methods.keys.sort
+    end
 end