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Diffstat (limited to 'lib/chef/mixin/descendants_tracker.rb')
-rw-r--r-- | lib/chef/mixin/descendants_tracker.rb | 82 |
1 files changed, 82 insertions, 0 deletions
diff --git a/lib/chef/mixin/descendants_tracker.rb b/lib/chef/mixin/descendants_tracker.rb new file mode 100644 index 0000000000..75d1f620d4 --- /dev/null +++ b/lib/chef/mixin/descendants_tracker.rb @@ -0,0 +1,82 @@ +# +# Copyright (c) 2005-2012 David Heinemeier Hansson +# +# Permission is hereby granted, free of charge, to any person obtaining +# a copy of this software and associated documentation files (the +# "Software"), to deal in the Software without restriction, including +# without limitation the rights to use, copy, modify, merge, publish, +# distribute, sublicense, and/or sell copies of the Software, and to +# permit persons to whom the Software is furnished to do so, subject to +# the following conditions: +# +# The above copyright notice and this permission notice shall be +# included in all copies or substantial portions of the Software. +# +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE +# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION +# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION +# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. +# + + +# This is lifted from rails activesupport (note the copyright above): +# https://github.com/rails/rails/blob/9f84e60ac9d7bf07d6ae1bc94f3941f5b8f1a228/activesupport/lib/active_support/descendants_tracker.rb + +class Chef + module Mixin + module DescendantsTracker + @@direct_descendants = {} + + class << self + def direct_descendants(klass) + @@direct_descendants[klass] || [] + end + + def descendants(klass) + arr = [] + accumulate_descendants(klass, arr) + arr + end + + def find_descendants_by_name(klass, name) + descendants(klass).first {|c| c.name == name } + end + + # This is the only method that is not thread safe, but is only ever called + # during the eager loading phase. + def store_inherited(klass, descendant) + (@@direct_descendants[klass] ||= []) << descendant + end + + private + + def accumulate_descendants(klass, acc) + if direct_descendants = @@direct_descendants[klass] + acc.concat(direct_descendants) + direct_descendants.each { |direct_descendant| accumulate_descendants(direct_descendant, acc) } + end + end + end + + def inherited(base) + DescendantsTracker.store_inherited(self, base) + super + end + + def direct_descendants + DescendantsTracker.direct_descendants(self) + end + + def find_descendants_by_name(name) + DescendantsTracker.find_descendants_by_name(self, name) + end + + def descendants + DescendantsTracker.descendants(self) + end + end + end +end |