couchrest_model/lib/couchrest/model/property.rb

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# encoding: utf-8
module CouchRest::Model
class Property
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include ::CouchRest::Model::Typecast
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attr_reader :name, :type, :type_class, :read_only, :alias, :default, :casted, :init_method, :options
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# Attribute to define.
# All Properties are assumed casted unless the type is nil.
def initialize(name, type = nil, options = {})
@name = name.to_s
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@casted = true
parse_type(type)
parse_options(options)
self
end
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def to_s
name
end
# Cast the provided value using the properties details.
def cast(parent, value)
return value unless casted
if type.is_a?(Array)
if value.nil?
value = []
elsif [Hash, HashWithIndifferentAccess].include?(value.class)
# Assume provided as a params hash where key is index
value = parameter_hash_to_array(value)
elsif !value.is_a?(Array)
raise "Expecting an array or keyed hash for property #{parent.class.name}##{self.name}"
end
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arr = value.collect { |data| cast_value(parent, data) }
# allow casted_by calls to be passed up chain by wrapping in CastedArray
CastedArray.new(arr, self, parent)
elsif (type == Object || type == Hash) && (value.is_a?(Hash))
# allow casted_by calls to be passed up chain by wrapping in CastedHash
CastedHash[value, self, parent]
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elsif !value.nil?
cast_value(parent, value)
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end
end
# Cast an individual value
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def cast_value(parent, value)
value = typecast_value(value, self)
associate_casted_value_to_parent(parent, value)
end
def default_value
return if default.nil?
if default.class == Proc
default.call
else
# TODO identify cause of mutex errors
Marshal.load(Marshal.dump(default))
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end
end
# Initialize a new instance of a property's type ready to be
# used. If a proc is defined for the init method, it will be used instead of
# a normal call to the class.
def build(*args)
raise StandardError, "Cannot build property without a class" if @type_class.nil?
if @init_method.is_a?(Proc)
@init_method.call(*args)
else
@type_class.send(@init_method, *args)
end
end
private
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def parameter_hash_to_array(source)
value = [ ]
source.keys.each do |k|
value[k.to_i] = source[k]
end
value.compact
end
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def associate_casted_value_to_parent(parent, value)
value.casted_by = parent if value.respond_to?(:casted_by)
value.casted_by_property = self if value.respond_to?(:casted_by_property)
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value
end
def parse_type(type)
if type.nil?
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@casted = false
@type = nil
@type_class = nil
else
base = type.is_a?(Array) ? type.first : type
base = Object if base.nil?
raise "Defining a property type as a #{type.class.name.humanize} is not supported in CouchRest Model!" if base.class != Class
@type_class = base
@type = type
end
end
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def parse_options(options)
@validation_format = options.delete(:format) if options[:format]
@read_only = options.delete(:read_only) if options[:read_only]
@alias = options.delete(:alias) if options[:alias]
@default = options.delete(:default) unless options[:default].nil?
@init_method = options[:init_method] ? options.delete(:init_method) : 'new'
@options = options
end
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end
end