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#--
# Copyright:: Copyright 2016, 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.
#
class Chef
class Node
# shared API between VividMash and ImmutableMash, writer code can be
# 'shared' to keep it logically in this file by adding them to the
# block list in ImmutableMash.
module CommonAPI
# method-style access to attributes
def valid_container?(obj, key)
return obj.is_a?(Hash) || (obj.is_a?(Array) && key.is_a?(Fixnum))
end
private :valid_container?
# - autovivifying / autoreplacing writer
# - non-container-ey intermediate objects are replaced with hashes
def write(*args, &block)
value = block_given? ? yield : args.pop
last = args.pop
prev_memo = prev_key = nil
chain = args.inject(self) do |memo, key|
if !valid_container?(memo, key)
prev_memo[prev_key] = {}
memo = prev_memo[prev_key]
end
prev_memo = memo
prev_key = key
memo[key]
end
if !valid_container?(chain, last)
prev_memo[prev_key] = {}
chain = prev_memo[prev_key]
end
chain[last] = value
end
# this autovivifies, but can throw NoSuchAttribute when trying to access #[] on
# something that is not a container ("schema violation" issues).
#
def write!(*args, &block)
value = block_given? ? yield : args.pop
last = args.pop
obj = args.inject(self) do |memo, key|
raise Chef::Exceptions::AttributeTypeMismatch unless valid_container?(memo, key)
memo[key]
end
raise Chef::Exceptions::AttributeTypeMismatch unless valid_container?(obj, last)
obj[last] = value
end
# FIXME:(?) does anyone need a non-autovivifying writer for attributes that throws exceptions?
# return true or false based on if the attribute exists
def exist?(*path)
path.inject(self) do |memo, key|
return false unless valid_container?(memo, key)
if memo.is_a?(Hash)
if memo.key?(key)
memo[key]
else
return false
end
elsif memo.is_a?(Array)
if memo.length > key
memo[key]
else
return false
end
end
end
return true
end
# this is a safe non-autovivifying reader that returns nil if the attribute does not exist
def read(*path)
begin
read!(*path)
rescue Chef::Exceptions::NoSuchAttribute
nil
end
end
# non-autovivifying reader that throws an exception if the attribute does not exist
def read!(*path)
raise Chef::Exceptions::NoSuchAttribute unless exist?(*path)
path.inject(self) do |memo, key|
memo[key]
end
end
# FIXME:(?) does anyone really like the autovivifying reader that we have and wants the same behavior? readers that write? ugh...
def unlink(*path, last)
hash = path.empty? ? self : read(*path)
return nil unless hash.is_a?(Hash) || hash.is_a?(Array)
hash.delete(last)
end
def unlink!(*path)
raise Chef::Exceptions::NoSuchAttribute unless exist?(*path)
unlink(*path)
end
end
end
end
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