gitlab-org--gitlab-foss/lib/gitlab/multi_collection_paginator.rb

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module Gitlab
class MultiCollectionPaginator
attr_reader :first_collection, :second_collection, :per_page
def initialize(*collections, per_page: nil)
raise ArgumentError.new('Only 2 collections are supported') if collections.size != 2
@per_page = per_page || Kaminari.config.default_per_page
@first_collection, @second_collection = collections
end
def paginate(page)
page = page.to_i
paginated_first_collection(page) + paginated_second_collection(page)
end
def total_count
@total_count ||= first_collection.size + second_collection.size
end
private
def paginated_first_collection(page)
@first_collection_pages ||= Hash.new do |hash, page|
hash[page] = first_collection.page(page).per(per_page)
end
@first_collection_pages[page]
end
def paginated_second_collection(page)
@second_collection_pages ||= Hash.new do |hash, page|
second_collection_page = page - first_collection_page_count
offset = if second_collection_page < 1 || first_collection_page_count.zero?
0
else
per_page - first_collection_last_page_size
end
hash[page] = second_collection.page(second_collection_page)
.per(per_page - paginated_first_collection(page).size)
.padding(offset)
end
@second_collection_pages[page]
end
def first_collection_page_count
return @first_collection_page_count if defined?(@first_collection_page_count)
first_collection_page = paginated_first_collection(0)
@first_collection_page_count = first_collection_page.total_pages
end
def first_collection_last_page_size
return @first_collection_last_page_size if defined?(@first_collection_last_page_size)
@first_collection_last_page_size = paginated_first_collection(first_collection_page_count)
.except(:select)
.size
end
end
end