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Move merging of Hashes out of the GroupDescendant concern

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Since it can technically merge any hash with objects that respond to `==`
This commit is contained in:
Bob Van Landuyt 2017-10-04 16:56:42 +02:00
parent 08383fd2e3
commit 06e00913f5
3 changed files with 154 additions and 53 deletions
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57
app/models/concerns/group_descendant.rb
View file

@ -5,22 +5,18 @@ module GroupDescendant
end
def self.build_hierarchy(descendants, hierarchy_top = nil)
descendants = Array.wrap(descendants)
descendants = Array.wrap(descendants).uniq
return [] if descendants.empty?
unless descendants.all? { |hierarchy| hierarchy.is_a?(GroupDescendant) }
raise ArgumentError.new('element is not a hierarchy')
end
first_descendant, *other_descendants = descendants
merged = first_descendant.hierarchy(hierarchy_top, descendants)
other_descendants.each do |descendant|
next_descendant = descendant.hierarchy(hierarchy_top, descendants)
merged = merge_hash_tree(merged, next_descendant)
all_hierarchies = descendants.map do |descendant|
descendant.hierarchy(hierarchy_top, descendants)
end
merged
Gitlab::Utils::MergeHash.merge(all_hierarchies)
end
private
@ -50,49 +46,4 @@ module GroupDescendant
hierarchy
end
end
private_class_method def self.merge_hash_tree(first_child, second_child)
# 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]
if first_child.is_a?(Array) && second_child.is_a?(Hash)
merge_hash_into_array(first_child, second_child)
elsif first_child.is_a?(Hash) && second_child.is_a?(Array)
merge_hash_into_array(second_child, first_child)
# If both of them are hashes, we can deep_merge with the same logic
#
# Handled cases:
# [Hash, Hash]
elsif first_child.is_a?(Hash) && second_child.is_a?(Hash)
first_child.deep_merge(second_child) { |key, first, second| merge_hash_tree(first, second) }
# If only one of them is a hash, and one of them is a GroupHierachy-object
# we can check if its already in the hash. If so, we don't need to do anything
#
# Handled cases
# [Hash, GroupDescendant]
elsif first_child.is_a?(Hash) && first_child.keys.include?(second_child)
first_child
elsif second_child.is_a?(Hash) && second_child.keys.include?(first_child)
second_child
# If one or both elements are a GroupDescendant, we wrap create an array
# combining them.
#
# Handled cases:
# [GroupDescendant, Array], [GroupDescendant, GroupDescendant], [Array, Array]
else
Array.wrap(first_child) + Array.wrap(second_child)
end
end
private_class_method def self.merge_hash_into_array(array, new_hash)
if mergeable_index = array.index { |element| element.is_a?(Hash) && (element.keys & new_hash.keys).any? }
array[mergeable_index] = merge_hash_tree(array[mergeable_index], new_hash)
else
array << new_hash
end
array
end
end

117
lib/gitlab/utils/merge_hash.rb Normal file
View file

@ -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

33
spec/lib/gitlab/utils/merge_hash_spec.rb Normal file
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@ -0,0 +1,33 @@
require 'spec_helper'
describe Gitlab::Utils::MergeHash do
describe '.crush' do
it 'can flatten a hash to each element' do
input = { hello: "world", this: { crushes: ["an entire", "hash"] } }
expected_result = [:hello, "world", :this, :crushes, "an entire", "hash"]
expect(described_class.crush(input)).to eq(expected_result)
end
end
describe '.elements' do
it 'deep merges an array of elements' do
input = [{ hello: ["world"] },
{ hello: "Everyone" },
{ hello: { greetings: ['Bonjour', 'Hello', 'Hallo', 'Dzień dobry'] } },
"Goodbye", "Hallo"]
expected_output = [
{
hello:
[
"world",
"Everyone",
{ greetings: ['Bonjour', 'Hello', 'Hallo', 'Dzień dobry'] }
]
},
"Goodbye"
]
expect(described_class.merge(input)).to eq(expected_output)
end
end
end