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rails--rails/railties/lib/rails/generators/migration.rb
2009-09-24 16:11:41 -07:00

65 lines
2.3 KiB
Ruby

module Rails
module Generators
# Holds common methods for migrations. It assumes that migrations has the
# [0-9]*_name format and can be used by another frameworks (like Sequel)
# just by implementing the next migration number method.
#
module Migration
def self.included(base) #:nodoc:
base.send :attr_reader, :migration_number,
:migration_file_name,
:migration_class_name
end
# Creates a migration template at the given destination. The difference
# to the default template method is that the migration number is appended
# to the destination file name.
#
# The migration number, migration file name, migration class name are
# available as instance variables in the template to be rendered.
#
# ==== Examples
#
# migration_template "migration.rb", "db/migrate/add_foo_to_bar.rb"
#
def migration_template(source, destination=nil, config={})
destination = File.expand_path(destination || source, self.destination_root)
migration_dir = File.dirname(destination)
@migration_number = next_migration_number(migration_dir)
@migration_file_name = File.basename(destination).sub(/\.rb$/, '')
@migration_class_name = @migration_file_name.camelize
destination = migration_exists?(migration_dir, @migration_file_name)
if behavior == :invoke
raise Error, "Another migration is already named #{@migration_file_name}: #{destination}" if destination
destination = File.join(migration_dir, "#{@migration_number}_#{@migration_file_name}.rb")
end
template(source, destination, config)
end
protected
def migration_lookup_at(dirname) #:nodoc:
Dir.glob("#{dirname}/[0-9]*_*.rb")
end
def migration_exists?(dirname, file_name) #:nodoc:
migration_lookup_at(dirname).grep(/\d+_#{file_name}.rb$/).first
end
def current_migration_number(dirname) #:nodoc:
migration_lookup_at(dirname).collect do |file|
File.basename(file).split("_").first.to_i
end.max.to_i
end
def next_migration_number(dirname) #:nodoc:
raise NotImplementError
end
end
end
end