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Contents
module ClosureTree
module HashTreeSupport
def default_tree_scope(scope, limit_depth = nil)
# Deepest generation, within limit, for each descendant
# NOTE: Postgres requires HAVING clauses to always contains aggregate functions (!!)
having_clause = limit_depth ? "HAVING MAX(generations) <= #{limit_depth - 1}" : ''
generation_depth = <<-SQL.strip_heredoc
INNER JOIN (
SELECT descendant_id, MAX(generations) as depth
FROM #{quoted_hierarchy_table_name}
GROUP BY descendant_id
#{having_clause}
) AS generation_depth
ON #{quoted_table_name}.#{model_class.primary_key} = generation_depth.descendant_id
SQL
scope_with_order(scope.joins(generation_depth), 'generation_depth.depth')
end
def hash_tree(tree_scope, limit_depth = nil)
limited_scope = limit_depth ? tree_scope.where("#{quoted_hierarchy_table_name}.generations <= #{limit_depth - 1}") : tree_scope
build_hash_tree(limited_scope)
end
# Builds nested hash structure using the scope returned from the passed in scope
def build_hash_tree(tree_scope)
tree = ActiveSupport::OrderedHash.new
id_to_hash = {}
tree_scope.each do |ea|
h = id_to_hash[ea.id] = ActiveSupport::OrderedHash.new
(id_to_hash[ea._ct_parent_id] || tree)[ea] = h
end
tree
end
end
end
Version data entries
6 entries across 6 versions & 1 rubygems