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require 'bindata/lazy'
module BinData
module AcceptedParametersPlugin
# Mandatory parameters must be present when instantiating a data object.
def mandatory_parameters(*args)
accepted_parameters.mandatory(*args)
end
# Optional parameters may be present when instantiating a data object.
def optional_parameters(*args)
accepted_parameters.optional(*args)
end
# Default parameters can be overridden when instantiating a data object.
def default_parameters(*args)
accepted_parameters.default(*args)
end
# Mutually exclusive parameters may not all be present when
# instantiating a data object.
def mutually_exclusive_parameters(*args)
accepted_parameters.mutually_exclusive(*args)
end
alias mandatory_parameter mandatory_parameters
alias optional_parameter optional_parameters
alias default_parameter default_parameters
def accepted_parameters #:nodoc:
@accepted_parameters ||= begin
ancestor_params = superclass.respond_to?(:accepted_parameters) ?
superclass.accepted_parameters : nil
AcceptedParameters.new(ancestor_params)
end
end
# BinData objects accept parameters when initializing. AcceptedParameters
# allow a BinData class to declaratively identify accepted parameters as
# mandatory, optional, default or mutually exclusive.
class AcceptedParameters
def initialize(ancestor_parameters = nil)
if ancestor_parameters
@mandatory = ancestor_parameters.mandatory.dup
@optional = ancestor_parameters.optional.dup
@default = ancestor_parameters.default.dup
@mutually_exclusive = ancestor_parameters.mutually_exclusive.dup
else
@mandatory = []
@optional = []
@default = Hash.new
@mutually_exclusive = []
end
end
def mandatory(*args)
unless args.empty?
@mandatory.concat(to_syms(args))
@mandatory.uniq!
end
@mandatory
end
def optional(*args)
unless args.empty?
@optional.concat(to_syms(args))
@optional.uniq!
end
@optional
end
def default(args = nil)
if args
to_syms(args.keys) # call for side effect of validating names
args.each_pair do |param, value|
@default[param.to_sym] = value
end
end
@default
end
def mutually_exclusive(*args)
arg1 = args.shift
until args.empty?
args.each do |arg2|
@mutually_exclusive.push([arg1.to_sym, arg2.to_sym])
@mutually_exclusive.uniq!
end
arg1 = args.shift
end
@mutually_exclusive
end
def all
(@mandatory + @optional + @default.keys).uniq
end
#---------------
private
def to_syms(args)
syms = args.collect(&:to_sym)
ensure_valid_names(syms)
syms
end
def ensure_valid_names(names)
invalid_names = self.class.invalid_parameter_names
names.each do |name|
if invalid_names.include?(name)
raise NameError.new("Rename parameter '#{name}' " \
"as it shadows an existing method.", name)
end
end
end
def self.invalid_parameter_names
@invalid_names ||= begin
all_names = LazyEvaluator.instance_methods(true)
allowed_names = [:name, :type]
invalid_names = (all_names - allowed_names).uniq
Hash[*invalid_names.collect { |key| [key.to_sym, true] }.flatten]
end
end
end
end
end
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