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#--
# Author:: Daniel DeLeo (<dan@opscode.com>)
# Copyright:: Copyright (c) 2012 Opscode, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
class Chef
class Node
# == AttrArray
# AttrArray is identical to Array, except that it keeps a reference to the
# "root" (Chef::Node::Attribute) object, and will trigger a cache
# invalidation on that object when mutated.
class AttrArray < Array
MUTATOR_METHODS = [
:<<,
:[]=,
:clear,
:collect!,
:compact!,
:default=,
:default_proc=,
:delete,
:delete_at,
:delete_if,
:fill,
:flatten!,
:insert,
:keep_if,
:map!,
:merge!,
:pop,
:push,
:update,
:reject!,
:reverse!,
:replace,
:select!,
:shift,
:slice!,
:sort!,
:sort_by!,
:uniq!,
:unshift
]
# For all of the methods that may mutate an Array, we override them to
# also invalidate the cached merged_attributes on the root
# Node::Attribute object.
MUTATOR_METHODS.each do |mutator|
class_eval(<<-METHOD_DEFN)
def #{mutator}(*args, &block)
root.reset_cache
super
end
METHOD_DEFN
end
attr_reader :root
def initialize(root, data)
@root = root
super(data)
end
end
# == VividMash
# VividMash is identical to a Mash, with a few exceptions:
# * It has a reference to the root Chef::Node::Attribute to which it
# belongs, and will trigger cache invalidation on that object when
# mutated.
# * It auto-vivifies, that is a reference to a missing element will result
# in the creation of a new VividMash for that key. (This only works when
# using the element reference method, `[]` -- other methods, such as
# #fetch, work as normal).
# * It supports a set_unless flag (via the root Attribute object) which
# allows `||=` style behavior (`||=` does not work with
# auto-vivification). This is only implemented for #[]=; methods such as
# #store work as normal.
# * attr_accessor style element set and get are supported via method_missing
class VividMash < Mash
attr_reader :root
# Methods that mutate a VividMash. Each of them is overridden so that it
# also invalidates the cached merged_attributes on the root Attribute
# object.
MUTATOR_METHODS = [
:clear,
:delete,
:delete_if,
:keep_if,
:merge!,
:update,
:reject!,
:replace,
:select!,
:shift
]
# For all of the mutating methods on Mash, override them so that they
# also invalidate the cached `merged_attributes` on the root Attribute
# object.
MUTATOR_METHODS.each do |mutator|
class_eval(<<-METHOD_DEFN)
def #{mutator}(*args, &block)
root.reset_cache
super
end
METHOD_DEFN
end
def initialize(root, data={})
@root = root
super(data)
end
def [](key)
value = super
if !key?(key)
value = self.class.new(root)
self[key] = value
else
value
end
end
def []=(key, value)
if set_unless? && key?(key)
self[key]
else
root.reset_cache
super
end
end
alias :attribute? :has_key?
def method_missing(symbol, *args)
if args.empty?
self[symbol]
elsif symbol.to_s =~ /=$/
key_to_set = symbol.to_s[/^(.+)=$/, 1]
self[key_to_set] = (args.length == 1 ? args[0] : args)
else
raise NoMethodError, "Undefined node attribute or method `#{symbol}' on `node'. To set an attribute, use `#{symbol}=value' instead."
end
end
def set_unless?
@root.set_unless?
end
def convert_key(key)
super
end
# Mash uses #convert_value to mashify values on input.
# We override it here to convert hash or array values to VividMash or
# AttrArray for consistency and to ensure that the added parts of the
# attribute tree will have the correct cache invalidation behavior.
def convert_value(value)
case value
when VividMash
value
when Hash
VividMash.new(root, value)
when Array
AttrArray.new(root, value)
else
value
end
end
end
end
end
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