Module: ClosureTree::HashTreeSupport

Included in:
Support
Defined in:
lib/closure_tree/hash_tree_support.rb

Instance Method Summary collapse

Instance Method Details

#build_hash_tree(tree_scope) ⇒ Object

Builds nested hash structure using the scope returned from the passed in scope



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# File 'lib/closure_tree/hash_tree_support.rb', line 25

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

#default_tree_scope(scope, limit_depth = nil) ⇒ Object 



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# File 'lib/closure_tree/hash_tree_support.rb', line 3

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

#hash_tree(tree_scope, limit_depth = nil) ⇒ Object 



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# File 'lib/closure_tree/hash_tree_support.rb', line 19

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