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require 'fileutils'
module Rails
module Generator
class GeneratorError < StandardError; end
class UsageError < GeneratorError; end
CONTRIB_ROOT = "#{RAILS_ROOT}/script/generators"
BUILTIN_ROOT = "#{File.dirname(__FILE__)}/../generators"
DEFAULT_SEARCH_PATHS = [CONTRIB_ROOT, BUILTIN_ROOT]
class << self
def instance(name, args = [], search_paths = DEFAULT_SEARCH_PATHS)
# RAILS_ROOT constant must be set.
unless Object.const_get(:RAILS_ROOT)
raise GeneratorError, "RAILS_ROOT must be set. Did you require 'config/environment'?"
end
# Force canonical name.
name = Inflector.underscore(name.downcase)
# Search for filesystem path to requested generator.
unless path = find_generator_path(name, search_paths)
raise GeneratorError, "#{name} generator not found."
end
# Check for templates directory.
template_root = "#{path}/templates"
unless File.directory?(template_root)
raise GeneratorError, "missing template directory #{template_root}"
end
# Require class file according to naming convention.
require "#{path}/#{name}_generator.rb"
# Find class according to naming convention. Allow Nesting::In::Modules.
class_name = Inflector.classify("#{name}_generator")
unless klass = find_generator_class(name)
raise GeneratorError, "no #{class_name} class defined in #{path}/#{name}_generator.rb"
end
# Instantiate and return generator.
klass.new(template_root, RAILS_ROOT, search_paths, args)
end
def builtin_generators
generators([BUILTIN_ROOT])
end
def contrib_generators
generators([CONTRIB_ROOT])
end
def generators(search_paths)
generator_paths(search_paths).keys.uniq.sort
end
# Find all generator paths.
def generator_paths(search_paths)
@paths ||= {}
unless @paths[search_paths]
paths = Hash.new { |h,k| h[k] = [] }
search_paths.each do |path|
Dir["#{path}/[a-z]*"].each do |dir|
paths[File.basename(dir)] << dir if File.directory?(dir)
end
end
@paths[search_paths] = paths
end
@paths[search_paths]
end
def find_generator_path(name, search_paths)
generator_paths(search_paths)[name].first
end
# Find all generator classes.
def generator_classes
classes = Hash.new { |h,k| h[k] = [] }
class_re = /([^:]+)Generator$/
ObjectSpace.each_object(Class) do |object|
if md = class_re.match(object.name) and object < Rails::Generator::Base
classes[Inflector.underscore(md.captures.first)] << object
end
end
classes
end
def find_generator_class(name)
generator_classes[name].first
end
end
# Talk about generators.
class Base
attr_reader :template_root, :destination_root, :args, :options,
:class_name, :singular_name, :plural_name
alias_method :file_name, :singular_name
alias_method :table_name, :plural_name
def self.generator_name
Inflector.underscore(name.gsub('Generator', ''))
end
def initialize(template_root, destination_root, search_paths, args)
@template_root, @destination_root = template_root, destination_root
usage if args.empty?
@search_paths, @original_args = search_paths, args.dup
@class_name, @singular_name, @plural_name = inflect_names(args.shift)
@options = extract_options!(args)
@args = args
end
# Checks whether the class name that was assigned to this generator
# would cause a collision with a Class, Module or other constant
# that is already used up by Ruby or RubyOnRails.
def collision_with_builtin?
builtin = Object.const_get(full_class_name) rescue nil
type = case builtin
when Class: "Class"
when Module: "Module"
else "Constant"
end
if builtin then
"Sorry, you can't have a #{self.class.generator_name} named\n" +
"'#{full_class_name}' because Ruby or RubyOnRails already has\n" +
"a #{type} with that name. Please rerun the generator with a\n" +
"different name."
end
end
# Returns the complete name that the resulting Class would have.
# Used in collision_with_builtin(). The default guess is that it is
# the same as class_name. Override this in your generator in case
# it is wrong.
def full_class_name
class_name
end
protected
# Look up another generator with the same arguments.
def generator(name)
Rails::Generator.instance(name, @original_args, @search_paths)
end
# Generate a file for a Rails application using an ERuby template.
# Looks up and evalutes a template by name and writes the result
# to a file relative to +destination_root+. The template
# is evaluated in the context of the optional eval_binding argument.
#
# 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.
def template(template_name, destination_path, eval_binding = nil)
# Determine full paths for source and destination files.
template_path = find_template_path(template_name)
destination_path = File.join(destination_root, destination_path)
# Create destination directories.
FileUtils.mkdir_p(File.dirname(destination_path))
# Render template and write result.
eval_binding ||= binding
contents = ERB.new(File.read(template_path), nil, '-').result(eval_binding)
File.open(destination_path, 'w') { |file| file.write(contents) }
end
def usage
raise UsageError.new, File.read(usage_path)
end
private
def find_template_path(template_name)
name, path = template_name.split('/', 2)
if path.nil?
File.join(template_root, name)
elsif generator_path = Rails::Generator.find_generator_path(name, @search_paths)
File.join(generator_path, 'templates', path)
end
end
def inflect_names(name)
camel = Inflector.camelize(Inflector.underscore(name))
under = Inflector.underscore(camel)
plural = Inflector.pluralize(under)
[camel, under, plural]
end
def extract_options!(args)
if args.last.is_a?(Hash) then args.pop else {} end
end
def usage_path
"#{template_root}/../USAGE"
end
end
end
end
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