require 'delegate' require 'optparse' require 'fileutils' require 'erb' module Rails module Generator module Commands # Here's a convenient way to get a handle on generator commands. # Command.instance('destroy', my_generator) instantiates a Destroy # delegate of my_generator ready to do your dirty work. def self.instance(command, generator) const_get(command.to_s.camelize).new(generator) end # Even more convenient access to commands. Include Commands in # the generator Base class to get a nice #command instance method # which returns a delegate for the requested command. def self.append_features(base) base.send(:define_method, :command) do |command| Commands.instance(command, self) end end # Generator commands delegate Rails::Generator::Base and implement # a standard set of actions. Their behavior is defined by the way # they respond to these actions: Create brings life; Destroy brings # death; List passively observes. # # Commands are invoked by replaying (or rewinding) the generator's # manifest of actions. See Rails::Generator::Manifest and # Rails::Generator::Base#manifest method that generator subclasses # are required to override. # # Commands allows generators to "plug in" invocation behavior, which # corresponds to the GoF Strategy pattern. class Base < DelegateClass(Rails::Generator::Base) # Replay action manifest. RewindBase subclass rewinds manifest. def invoke! manifest.replay(self) end def dependency(generator_name, args, runtime_options = {}) logger.dependency(generator_name) do self.class.new(instance(generator_name, args, full_options(runtime_options))).invoke! end end # Does nothing for all commands except Create. def class_collisions(*class_names) end # Does nothing for all commands except Create. def readme(*args) end protected def migration_directory(relative_path) directory(@migration_directory = relative_path) end def existing_migrations(file_name) Dir.glob("#{@migration_directory}/[0-9]*_#{file_name}.rb") end def migration_exists?(file_name) not existing_migrations(file_name).empty? end def current_migration_number Dir.glob("#{@migration_directory}/[0-9]*.rb").inject(0) do |max, file_path| n = File.basename(file_path).split('_', 2).first.to_i if n > max then n else max end end end def next_migration_number current_migration_number + 1 end def next_migration_string(padding = 3) "%.#{padding}d" % next_migration_number end private # Ask the user interactively whether to force collision. def force_file_collision?(destination) $stdout.print "overwrite #{destination}? [Ynaq] " case $stdin.gets when /a/i $stdout.puts "forcing #{spec.name}" options[:collision] = :force when /q/i $stdout.puts "aborting #{spec.name}" raise SystemExit when /n/i then :skip else :force end rescue retry end def render_template_part(template_options) # Getting Sandbox to evaluate part template in it part_binding = template_options[:sandbox].call.sandbox_binding part_rel_path = template_options[:insert] part_path = source_path(part_rel_path) # Render inner template within Sandbox binding rendered_part = ERB.new(File.readlines(part_path).join, nil, '-').result(part_binding) begin_mark = template_part_mark(template_options[:begin_mark], template_options[:mark_id]) end_mark = template_part_mark(template_options[:end_mark], template_options[:mark_id]) begin_mark + rendered_part + end_mark end def template_part_mark(name, id) "\n" end end # Base class for commands which handle generator actions in reverse, such as Destroy. class RewindBase < Base # Rewind action manifest. def invoke! manifest.rewind(self) end end # Create is the premier generator command. It copies files, creates # directories, renders templates, and more. class Create < Base # Check whether the given class names are already taken by # Ruby or Rails. In the future, expand to check other namespaces # such as the rest of the user's app. def class_collisions(*class_names) class_names.flatten.each do |class_name| # Convert to string to allow symbol arguments. class_name = class_name.to_s # Skip empty strings. next if class_name.strip.empty? # Split the class from its module nesting. nesting = class_name.split('::') name = nesting.pop # Extract the last Module in the nesting. last = nesting.inject(Object) { |last, nest| break unless last.const_defined?(nest) last.const_get(nest) } # If the last Module exists, check whether the given # class exists and raise a collision if so. if last and last.const_defined?(name.camelize) raise_class_collision(class_name) end end end # Copy a file from source to destination with collision checking. # # The file_options hash accepts :chmod and :shebang options. # :chmod sets the permissions of the destination file: # file 'config/empty.log', 'log/test.log', :chmod => 0664 # :shebang sets the #!/usr/bin/ruby line for scripts # file 'bin/generate.rb', 'script/generate', :chmod => 0755, :shebang => '/usr/bin/env ruby' # # Collisions are handled by checking whether the destination file # exists and either skipping the file, forcing overwrite, or asking # the user what to do. def file(relative_source, relative_destination, file_options = {}, &block) # Determine full paths for source and destination files. source = source_path(relative_source) destination = destination_path(relative_destination) destination_exists = File.exists?(destination) # If source and destination are identical then we're done. if destination_exists and identical?(source, destination, &block) return logger.identical(relative_destination) end # Check for and resolve file collisions. if destination_exists # Make a choice whether to overwrite the file. :force and # :skip already have their mind made up, but give :ask a shot. choice = case options[:collision].to_sym #|| :ask when :ask then force_file_collision?(relative_destination) when :force then :force when :skip then :skip else raise "Invalid collision option: #{options[:collision].inspect}" end # Take action based on our choice. Bail out if we chose to # skip the file; otherwise, log our transgression and continue. case choice when :force then logger.force(relative_destination) when :skip then return(logger.skip(relative_destination)) else raise "Invalid collision choice: #{choice}.inspect" end # File doesn't exist so log its unbesmirched creation. else logger.create relative_destination end # If we're pretending, back off now. return if options[:pretend] # Write destination file with optional shebang. Yield for content # if block given so templaters may render the source file. If a # shebang is requested, replace the existing shebang or insert a # new one. File.open(destination, 'w') do |df| File.open(source) do |sf| if block_given? df.write(yield(sf)) else line = sf.gets || '' if file_options[:shebang] df.puts("#!#{file_options[:shebang]}") df.puts(line) if line !~ /^#!/ else df.puts(line) end df.write(sf.read) end end end # Optionally change permissions. if file_options[:chmod] FileUtils.chmod(file_options[:chmod], destination) end # Optionally add file to subversion system("svn add #{destination}") if options[:svn] end # Checks if the source and the destination file are identical. If # passed a block then the source file is a template that needs to first # be evaluated before being compared to the destination. def identical?(source, destination, &block) return false if File.directory? destination source = block_given? ? File.open(source) {|sf| yield(sf)} : IO.read(source) destination = IO.read(destination) source == destination end # Generate a file for a Rails application using an ERuby template. # Looks up and evalutes a template by name and writes the result. # # The ERB template uses explicit trim mode to best control the # proliferation of whitespace in generated code. <%- trims leading # whitespace; -%> trims trailing whitespace including one newline. # # A hash of template options may be passed as the last argument. # The options accepted by the file are accepted as well as :assigns, # a hash of variable bindings. Example: # template 'foo', 'bar', :assigns => { :action => 'view' } # # Template is implemented in terms of file. It calls file with a # block which takes a file handle and returns its rendered contents. def template(relative_source, relative_destination, template_options = {}) file(relative_source, relative_destination, template_options) do |file| # Evaluate any assignments in a temporary, throwaway binding. vars = template_options[:assigns] || {} b = binding vars.each { |k,v| eval "#{k} = vars[:#{k}] || vars['#{k}']", b } # Render the source file with the temporary binding. ERB.new(file.read, nil, '-').result(b) end end def complex_template(relative_source, relative_destination, template_options = {}) options = template_options.dup options[:assigns] ||= {} options[:assigns]['template_for_inclusion'] = render_template_part(template_options) template(relative_source, relative_destination, options) end # Create a directory including any missing parent directories. # Always directories which exist. def directory(relative_path) path = destination_path(relative_path) if File.exists?(path) logger.exists relative_path else logger.create relative_path FileUtils.mkdir_p(path) unless options[:pretend] # Optionally add file to subversion system("svn add #{path}") if options[:svn] end end # Display a README. def readme(*relative_sources) relative_sources.flatten.each do |relative_source| logger.readme relative_source puts File.read(source_path(relative_source)) unless options[:pretend] end end # When creating a migration, it knows to find the first available file in db/migrate and use the migration.rb template. def migration_template(relative_source, relative_destination, template_options = {}) migration_directory relative_destination raise "Another migration is already named #{file_name}: #{existing_migrations(file_name).first}" if migration_exists?(file_name) template(relative_source, "#{relative_destination}/#{next_migration_string}_#{file_name}.rb", template_options) end private # Raise a usage error with an informative WordNet suggestion. # Thanks to Florian Gross (flgr). def raise_class_collision(class_name) message = <", "") data.scan(/^Sense \d+\n.+?\n\n/m) end end rescue Exception return nil end end # Undo the actions performed by a generator. Rewind the action # manifest and attempt to completely erase the results of each action. class Destroy < RewindBase # Remove a file if it exists and is a file. def file(relative_source, relative_destination, file_options = {}) destination = destination_path(relative_destination) if File.exists?(destination) logger.rm relative_destination unless options[:pretend] if options[:svn] # If the file has been marked to be added # but has not yet been checked in, revert and delete if options[:svn][relative_destination] system("svn revert #{destination}") FileUtils.rm(destination) else # If the directory is not in the status list, it # has no modifications so we can simply remove it system("svn rm #{destination}") end else FileUtils.rm(destination) end end else logger.missing relative_destination return end end # Templates are deleted just like files and the actions take the # same parameters, so simply alias the file method. alias_method :template, :file # Remove each directory in the given path from right to left. # Remove each subdirectory if it exists and is a directory. def directory(relative_path) parts = relative_path.split('/') until parts.empty? partial = File.join(parts) path = destination_path(partial) if File.exists?(path) if Dir[File.join(path, '*')].empty? logger.rmdir partial unless options[:pretend] if options[:svn] # If the directory has been marked to be added # but has not yet been checked in, revert and delete if options[:svn][relative_path] system("svn revert #{path}") FileUtils.rmdir(path) else # If the directory is not in the status list, it # has no modifications so we can simply remove it system("svn rm #{path}") end else FileUtils.rmdir(path) end end else logger.notempty partial end else logger.missing partial end parts.pop end end def complex_template(*args) # nothing should be done here end # When deleting a migration, it knows to delete every file named "[0-9]*_#{file_name}". def migration_template(relative_source, relative_destination, template_options = {}) migration_directory relative_destination raise "There is no migration named #{file_name}" unless migration_exists?(file_name) existing_migrations(file_name).each do |file_path| file(relative_source, file_path, template_options) end end end # List a generator's action manifest. class List < Base def dependency(generator_name, args, options = {}) logger.dependency "#{generator_name}(#{args.join(', ')}, #{options.inspect})" end def class_collisions(*class_names) logger.class_collisions class_names.join(', ') end def file(relative_source, relative_destination, options = {}) logger.file relative_destination end def template(relative_source, relative_destination, options = {}) logger.template relative_destination end def complex_template(relative_source, relative_destination, options = {}) logger.template "#{options[:insert]} inside #{relative_destination}" end def directory(relative_path) logger.directory "#{destination_path(relative_path)}/" end def readme(*args) logger.readme args.join(', ') end def migration_template(relative_source, relative_destination, options = {}) migration_directory relative_destination logger.migration_template file_name end end # Update generator's action manifest. class Update < Create def file(relative_source, relative_destination, options = {}) # logger.file relative_destination end def template(relative_source, relative_destination, options = {}) # logger.template relative_destination end def complex_template(relative_source, relative_destination, template_options = {}) begin dest_file = destination_path(relative_destination) source_to_update = File.readlines(dest_file).join rescue Errno::ENOENT logger.missing relative_destination return end logger.refreshing "#{template_options[:insert].gsub(/\.rhtml/,'')} inside #{relative_destination}" begin_mark = Regexp.quote(template_part_mark(template_options[:begin_mark], template_options[:mark_id])) end_mark = Regexp.quote(template_part_mark(template_options[:end_mark], template_options[:mark_id])) # Refreshing inner part of the template with freshly rendered part. rendered_part = render_template_part(template_options) source_to_update.gsub!(/#{begin_mark}.*?#{end_mark}/m, rendered_part) File.open(dest_file, 'w') { |file| file.write(source_to_update) } end def directory(relative_path) # logger.directory "#{destination_path(relative_path)}/" end end end end end