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#--
# Copyright:: Copyright 2012-2018, Chef Software 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.
#
require "chef/node/common_api"
require "chef/node/mixin/state_tracking"
require "chef/node/mixin/immutablize_array"
require "chef/node/mixin/immutablize_hash"
class Chef
class Node
module Immutablize
# For elements like Fixnums, true, nil...
def safe_dup(e)
e.dup
rescue TypeError
e
end
def convert_value(value, path = nil)
case value
when Hash
ImmutableMash.new({}, __root__, __node__, __precedence__, path)
when Array
ImmutableArray.new([], __root__, __node__, __precedence__, path)
else
safe_dup(value).freeze
end
end
end
# == ImmutableArray
# ImmutableArray is used to implement Array collections when reading node
# attributes.
#
# ImmutableArray acts like an ordinary Array, except:
# * Methods that mutate the array are overridden to raise an error, making
# the collection more or less immutable.
# * Since this class stores values computed from a parent
# Chef::Node::Attribute's values, it overrides all reader methods to
# detect staleness and raise an error if accessed when stale.
class ImmutableArray < Array
alias_method :internal_clear, :clear
alias_method :internal_replace, :replace
alias_method :internal_push, :<<
alias_method :internal_to_a, :to_a
alias_method :internal_each, :each
private :internal_push, :internal_replace, :internal_clear, :internal_each
protected :internal_to_a
include Immutablize
methods = Array.instance_methods - Object.instance_methods +
[ :!, :!=, :<=>, :==, :===, :eql?, :to_s, :hash, :key, :has_key?, :inspect, :pretty_print, :pretty_print_inspect, :pretty_print_cycle, :pretty_print_instance_variables ]
methods.each do |method|
define_method method do |*args, &block|
ensure_generated_cache!
super(*args, &block)
end
end
def each
ensure_generated_cache!
# aggressively pre generate the cache, works around ruby being too smart and fiddling with internals
internal_each { |i| i.ensure_generated_cache! if i.respond_to?(:ensure_generated_cache!) }
super
end
# because sometimes ruby gives us back Arrays or ImmutableArrays out of objects from things like #uniq or array slices
def return_normal_array(array)
if array.respond_to?(:internal_to_a, true)
array.internal_to_a
else
array.to_a
end
end
def uniq
ensure_generated_cache!
return_normal_array(super)
end
def initialize(array_data = [])
# Immutable collections no longer have initialized state
end
# For elements like Fixnums, true, nil...
def safe_dup(e)
e.dup
rescue TypeError
e
end
def dup
Array.new(map { |e| safe_dup(e) })
end
def to_a
Array.new(map do |v|
case v
when ImmutableArray
v.to_a
when ImmutableMash
v.to_h
else
safe_dup(v)
end
end)
end
alias_method :to_array, :to_a
def [](*args)
ensure_generated_cache!
args.length > 1 ? return_normal_array(super) : super # correctly handle array slices
end
def reset
@generated_cache = false
@short_circuit_attr_level = nil
internal_clear # redundant?
end
# @api private
def ensure_generated_cache!
generate_cache unless @generated_cache
@generated_cache = true
end
# This can be set to e.g. [ :@default ] by the parent container to cause this container
# to only use the default level and to bypass deep merging (the common case is either
# default-level or automatic-level and we aren't doing any deep merging). Right now it
# "optimized" for the case where we're no longer merging anything and only tracking a
# single level, and setting this to anything other than a size=1 array would behave
# in a broken fashion. That could be fixed, but the perf boost would likely not be
# that large in the typical case.
#
# @api private
attr_accessor :short_circuit_attr_levels
private
# deep merging of array attribute within normal and override where they are merged together
def combined_components(components)
combined_values = nil
components.each do |component|
values = __node__.attributes.instance_variable_get(component).read(*__path__)
next unless values.is_a?(Array)
@tracked_components << component
combined_values ||= []
combined_values += values
end
combined_values
end
def get_array(component)
array = __node__.attributes.instance_variable_get(component).read(*__path__)
if array.is_a?(Array)
@tracked_components << component
array
end # else nil
end
def generate_cache
internal_clear
components = []
@tracked_components = []
if short_circuit_attr_levels
components << get_array(short_circuit_attr_levels.first)
else
components << combined_components(Attribute::DEFAULT_COMPONENTS)
components << get_array(:@normal)
components << combined_components(Attribute::OVERRIDE_COMPONENTS)
components << get_array(:@automatic)
end
highest = components.compact.last
if highest.is_a?(Array)
internal_replace( highest.each_with_index.map { |x, i| convert_value(x, __path__ + [ i ] ) } )
end
if @tracked_components.size == 1
# tracked_components is accurate enough to tell us if we're not really merging
internal_each do |key, value|
value.short_circuit_attr_levels = @tracked_components if value.respond_to?(:short_circuit_attr_levels)
end
end
end
# needed for __path__
def convert_key(key)
key
end
prepend Chef::Node::Mixin::StateTracking
prepend Chef::Node::Mixin::ImmutablizeArray
end
# == ImmutableMash
# ImmutableMash implements Hash/Dict behavior for reading values from node
# attributes.
#
# ImmutableMash acts like a Mash (Hash that is indifferent to String or
# Symbol keys), with some important exceptions:
# * Methods that mutate state are overridden to raise an error instead.
# * Methods that read from the collection are overriden so that they check
# if the Chef::Node::Attribute has been modified since an instance of
# this class was generated. An error is raised if the object detects that
# it is stale.
# * Values can be accessed in attr_reader-like fashion via method_missing.
class ImmutableMash < Mash
alias_method :internal_clear, :clear
alias_method :internal_key?, :key? # FIXME: could bypass convert_key in Mash for perf
alias_method :internal_each, :each
include Immutablize
include CommonAPI
methods = Hash.instance_methods - Object.instance_methods +
[ :!, :!=, :<=>, :==, :===, :eql?, :to_s, :hash, :key, :has_key?, :inspect, :pretty_print, :pretty_print_inspect, :pretty_print_cycle, :pretty_print_instance_variables ]
methods.each do |method|
define_method method do |*args, &block|
ensure_generated_cache!
super(*args, &block)
end
end
# this is for deep_merge usage, chef users must never touch this API
# @api private
def internal_set(key, value)
regular_writer(key, convert_value(value, __path__ + [ key ]))
end
def initialize(mash_data = {})
# Immutable collections no longer have initialized state
end
alias :attribute? :has_key?
# NOTE: #default and #default= are likely to be pretty confusing. For a
# regular ruby Hash, they control what value is returned for, e.g.,
# hash[:no_such_key] #=> hash.default
# Of course, 'default' has a specific meaning in Chef-land
def dup
h = Mash.new
each_pair do |k, v|
h[k] = safe_dup(v)
end
h
end
def to_h
h = Hash.new
each_pair do |k, v|
h[k] =
case v
when ImmutableMash
v.to_h
when ImmutableArray
v.to_a
else
safe_dup(v)
end
end
h
end
alias_method :to_hash, :to_h
def [](key)
ensure_generated_cache!
super
end
def reset
@generated_cache = false
@short_circuit_attr_level = nil
internal_clear # redundant?
end
# @api private
def ensure_generated_cache!
generate_cache unless @generated_cache
@generated_cache = true
end
# @api private
attr_accessor :short_circuit_attr_levels
private
def generate_cache
internal_clear
components = short_circuit_attr_levels ? short_circuit_attr_levels : Attribute::COMPONENTS.reverse
# tracked_components is not entirely accurate due to the short-circuit
tracked_components = []
components.each do |component|
subhash = __node__.attributes.instance_variable_get(component).read(*__path__)
unless subhash.nil? # FIXME: nil is used for not present
tracked_components << component
if subhash.kind_of?(Hash)
subhash.each_key do |key|
next if internal_key?(key)
internal_set(key, subhash[key])
end
else
break
end
end
end
if tracked_components.size == 1
# tracked_components is accurate enough to tell us if we're not really merging
internal_each do |key, value|
value.short_circuit_attr_levels = tracked_components if value.respond_to?(:short_circuit_attr_levels)
end
end
end
prepend Chef::Node::Mixin::StateTracking
prepend Chef::Node::Mixin::ImmutablizeHash
end
end
end
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