Added new generator framework that informs about its doings on generation and enables updating and destruction of generated artifacts. See the new script/destroy and script/update for more details #487 [bitsweat]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@518 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 135 insertions, 0 deletions

diff --git a/railties/lib/rails_generator/options.rb b/railties/lib/rails_generator/options.rb
new file mode 100644
index 0000000000..afe2d31625
--- /dev/null
+++ b/railties/lib/rails_generator/options.rb
@@ -0,0 +1,135 @@
+require 'optparse'
+require File.dirname(__FILE__) + '/../support/class_inheritable_attributes'
+
+module Rails
+  module Generator
+    module Options
+      def self.append_features(base)
+        super
+        base.extend(ClassMethods)
+        class << base
+          if respond_to?(:inherited)
+            alias_method :inherited_without_options, :inherited
+          end
+          alias_method :inherited, :inherited_with_options
+        end
+      end
+
+      module ClassMethods
+        def inherited_with_options(sub)
+          inherited_without_options(sub) if respond_to?(:inherited_without_options)
+          sub.extend(Rails::Generator::Options::ClassMethods)
+        end
+
+        def mandatory_options(options = nil)
+          if options
+            write_inheritable_attribute(:mandatory_options, options)
+          else
+            read_inheritable_attribute(:mandatory_options) or write_inheritable_attribute(:mandatory_options, {})
+          end
+        end
+
+        def default_options(options = nil)
+          if options
+            write_inheritable_attribute(:default_options, options)
+          else
+            read_inheritable_attribute(:default_options) or write_inheritable_attribute(:default_options, {})
+          end
+        end
+
+        # Merge together our class options.  In increasing precedence:
+        #   default_options   (class default options)
+        #   runtime_options   (provided as argument)
+        #   mandatory_options (class mandatory options)
+        def full_options(runtime_options = {})
+          default_options.merge(runtime_options).merge(mandatory_options)
+        end
+
+      end
+
+      # Each instance has an options hash that's populated by #parse.
+      def options
+        @options ||= {}
+      end
+      attr_writer :options
+
+      protected
+        # Convenient access to class mandatory options.
+        def mandatory_options
+          self.class.mandatory_options
+        end
+
+        # Convenient access to class default options.
+        def default_options
+          self.class.default_options
+        end
+
+        # Merge together our instance options.  In increasing precedence:
+        #   default_options   (class default options)
+        #   options           (instance options)
+        #   runtime_options   (provided as argument)
+        #   mandatory_options (class mandatory options)
+        def full_options(runtime_options = {})
+          self.class.full_options(options.merge(runtime_options))
+        end
+
+        # Parse arguments into the options hash.  Classes may customize
+        # parsing behavior by overriding these methods:
+        #   #banner                 Usage: ./script/generate [options]
+        #   #add_options!           Options:
+        #                             some options..
+        #   #add_general_options!   General Options:
+        #                             general options..
+        def parse!(args, runtime_options = {})
+          self.options = {}
+
+          @option_parser = OptionParser.new do |opt|
+            opt.banner = banner
+            add_options!(opt)
+            add_general_options!(opt)
+            opt.parse!(args)
+          end
+
+          self.options = full_options(runtime_options)
+          args
+        end
+
+        # Raise a usage error.  Override usage_message to provide a blurb
+        # after the option parser summary.
+        def usage
+          raise UsageError, "#{@option_parser}\n#{usage_message}"
+        end
+
+        def usage_message
+          ''
+        end
+
+        # Override with your own usage banner.
+        def banner
+          "Usage: #{$0} [options]"
+        end
+
+        # Override with a method that adds options to the parser.
+        # Added options should use the options hash.  For example,
+        #   def add_options!(opt)
+        #     opt.on('-v', '--verbose') { |value| options[:verbose] = value }
+        #   end
+        def add_options!(opt)
+        end
+
+        # Adds general options like -h and --quiet.  Usually don't override.
+        def add_general_options!(opt)
+          opt.separator ''
+          opt.separator 'General Options:'
+
+          opt.on('-p', '--pretend', 'Run but do not make any changes.') { |options[:pretend]| }
+          opt.on('-f', '--force', 'Overwrite files that already exist.') { options[:collision] = :force }
+          opt.on('-s', '--skip', 'Skip files that already exist.') { options[:collision] = :skip }
+          opt.on('-q', '--quiet', 'Keep is like a secret with /dev/null.') { |options[:quiet]| }
+          opt.on('-t', '--backtrace', 'Debugging: show backtrace on errors.') { |options[:backtrace]| }
+          opt.on('-h', '--help', 'Show this help message.') { |options[:help]| }
+        end
+
+    end
+  end
+end