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Diffstat (limited to 'lib/gitlab/utils/merge_hash.rb')
-rw-r--r-- | lib/gitlab/utils/merge_hash.rb | 117 |
1 files changed, 117 insertions, 0 deletions
diff --git a/lib/gitlab/utils/merge_hash.rb b/lib/gitlab/utils/merge_hash.rb new file mode 100644 index 00000000000..385141d44d0 --- /dev/null +++ b/lib/gitlab/utils/merge_hash.rb @@ -0,0 +1,117 @@ +module Gitlab + module Utils + module MergeHash + extend self + # Deep merges an array of hashes + # + # [{ hello: ["world"] }, + # { hello: "Everyone" }, + # { hello: { greetings: ['Bonjour', 'Hello', 'Hallo', 'Dzien dobry'] } }, + # "Goodbye", "Hallo"] + # => [ + # { + # hello: + # [ + # "world", + # "Everyone", + # { greetings: ['Bonjour', 'Hello', 'Hallo', 'Dzien dobry'] } + # ] + # }, + # "Goodbye" + # ] + def merge(elements) + merged, *other_elements = elements + + other_elements.each do |element| + merged = merge_hash_tree(merged, element) + end + + merged + end + + # This extracts all keys and values from a hash into an array + # + # { hello: "world", this: { crushes: ["an entire", "hash"] } } + # => [:hello, "world", :this, :crushes, "an entire", "hash"] + def crush(array_or_hash) + if array_or_hash.is_a?(Array) + crush_array(array_or_hash) + else + crush_hash(array_or_hash) + end + end + + private + + def merge_hash_into_array(array, new_hash) + crushed_new_hash = crush_hash(new_hash) + # Merge the hash into an existing element of the array if there is overlap + if mergeable_index = array.index { |element| crushable?(element) && (crush(element) & crushed_new_hash).any? } + array[mergeable_index] = merge_hash_tree(array[mergeable_index], new_hash) + else + array << new_hash + end + + array + end + + def merge_hash_tree(first_element, second_element) + # If one of the elements is an object, and the other is a Hash or Array + # we can check if the object is already included. If so, we don't need to do anything + # + # Handled cases + # [Hash, Object], [Array, Object] + if crushable?(first_element) && crush(first_element).include?(second_element) + first_element + elsif crushable?(second_element) && crush(second_element).include?(first_element) + second_element + # When the first is an array, we need to go over every element to see if + # we can merge deeper. If no match is found, we add the element to the array + # + # Handled cases: + # [Array, Hash] + elsif first_element.is_a?(Array) && second_element.is_a?(Hash) + merge_hash_into_array(first_element, second_element) + elsif first_element.is_a?(Hash) && second_element.is_a?(Array) + merge_hash_into_array(second_element, first_element) + # If both of them are hashes, we can deep_merge with the same logic + # + # Handled cases: + # [Hash, Hash] + elsif first_element.is_a?(Hash) && second_element.is_a?(Hash) + first_element.deep_merge(second_element) { |key, first, second| merge_hash_tree(first, second) } + # If both elements are arrays, we try to merge each element separatly + # + # Handled cases + # [Array, Array] + elsif first_element.is_a?(Array) && second_element.is_a?(Array) + first_element.map { |child_element| merge_hash_tree(child_element, second_element) } + # If one or both elements are a GroupDescendant, we wrap create an array + # combining them. + # + # Handled cases: + # [Object, Object], [Array, Array] + else + (Array.wrap(first_element) + Array.wrap(second_element)).uniq + end + end + + def crushable?(element) + element.is_a?(Hash) || element.is_a?(Array) + end + + def crush_hash(hash) + hash.flat_map do |key, value| + crushed_value = crushable?(value) ? crush(value) : value + Array.wrap(key) + Array.wrap(crushed_value) + end + end + + def crush_array(array) + array.flat_map do |element| + crushable?(element) ? crush(element) : element + end + end + end + end +end |