Class: SimpleNestedSet::NestedSet

Inherits:
ActiveRecord::Relation
  • Object
show all
Includes:
SqlAbstraction
Defined in:
lib/simple_nested_set/nested_set.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from SqlAbstraction

#group_concat, #order_by

Constructor Details

#initialize(*args) ⇒ NestedSet

Returns a new instance of NestedSet.



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# File 'lib/simple_nested_set/nested_set.rb', line 35

def initialize(*args)
  super(node_class, node_class.arel_table)
  @node = args.first if args.size == 1
  @where_values = self.class.scope(args.first).instance_variable_get(:@where_values) if args.size == 1
  # TODO how to set order(:lft) here? it's now being added on various scopes (see class methods), would be better to have it here.
end

Instance Attribute Details

#node ⇒ Object (readonly)

Returns the value of attribute node.



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# File 'lib/simple_nested_set/nested_set.rb', line 33

def node
  @node
end

Class Method Details

.build_class(model, scopes) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 8

def build_class(model, scopes)
  model.const_get(:NestedSet) rescue model.const_set(:NestedSet, Class.new(NestedSet)).tap do |node_class|
    node_class.node_class = model
    node_class.move_after_save = true
    node_class.scope_names = Array(scopes).map { |s| s.to_s =~ /_id$/ ? s.to_sym : :"#{s}_id" }
  end
end

.extract_attributes!(attributes) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 26

def extract_attributes!(attributes)
  attributes.slice(*SimpleNestedSet::ATTRIBUTES).tap do
    attributes.except!(*(SimpleNestedSet::ATTRIBUTES - [:path, :parent, :parent_id]))
  end if attributes.respond_to?(:slice)
end

.scope(scope) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 16

def scope(scope)
  scope.blank? ? node_class.scoped : node_class.where(scope_condition(scope))
end

.scope_condition(scope) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 20

def scope_condition(scope)
  scope_names.inject({}) do |c, name|
    c.merge(name => scope.respond_to?(name) ? scope.send(name) : scope[name])
  end
end

Instance Method Details

#attribute_names ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 127

def attribute_names
  @attribute_names ||= node.attribute_names.select { |attribute| ATTRIBUTES.include?(attribute.to_sym) }
end

#db_adapter ⇒ Object

def denormalize_query_mysql(field)

synonym = field.to_s.reverse.to_sym
aliaz = arel_table.as("table_#{synonym}")

field_sql = yield aliaz

query = [
  aliaz.project("#{field_sql} AS field_#{synonym}", aliaz[:lft], aliaz[:rgt]).to_sql,
  ' WHERE ',
  where_clauses.map { |clause| clause.gsub(arel_table.name, aliaz.table_alias.to_s) }.join(' AND ')
].join

<<-sql
  #{field} = (
    SELECT #{aliaz.table_alias.to_s}.field_#{synonym}
    FROM (#{query}) AS #{aliaz.table_alias.to_s}
    WHERE #{aliaz[:lft].lt(arel_table[:lft]).to_sql}
      AND #{aliaz[:rgt].gt(arel_table[:rgt]).to_sql}
  )
sql

end



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# File 'lib/simple_nested_set/nested_set.rb', line 222

def db_adapter
  node.class.connection.instance_variable_get('@config')[:adapter].to_sym
end

#denormalize! ⇒ Object

FIXME This needs to be abstracted away into the SqlAbstraction module FIXME we don’t always want to call this on after_save, do we? it’s only relevant when either the structure or the slug has changed



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# File 'lib/simple_nested_set/nested_set.rb', line 60

def denormalize!
  sql = []

  case db_adapter
  when :mysql, :mysql2
    sql << <<-sql if node.has_attribute?(:level)
`level` = (
  SELECT tmp.lev
  FROM (
SELECT n0.id, count(*) AS lev
FROM #{arel_table.name} AS n0
  CROSS JOIN #{arel_table.name} AS n1
WHERE n1.lft < n0.lft AND n1.rgt > n0.rgt
GROUP BY n0.id
  ) AS tmp
  WHERE ( #{arel_table.name}.id = tmp.id )
)
    sql

    scoping = [
      'n1.lft <= n0.lft AND n1.rgt >= n0.rgt',
      where_clauses.map { |clause| clause.gsub(arel_table.name, 'n1') }
    ].flatten.compact.join(' AND ')

    sql << <<-sql if node.has_attribute?(:path)
`path` = (
  SELECT tmp.pat
  FROM (
SELECT n0.id, #{group_concat(db_adapter, "n1`.`slug" )} AS pat
FROM (SELECT * FROM #{arel_table.name} ORDER BY `lft`) AS n0
  CROSS JOIN (SELECT * FROM #{arel_table.name} ORDER BY `lft`) AS n1
WHERE #{scoping}
GROUP BY n0.id
  ) AS tmp
  WHERE ( #{arel_table.name}.id = tmp.id )
)
    sql
  else
    sql << denormalize_level_query if node.has_attribute?(:level)
    sql << denormalize_path_query  if node.has_attribute?(:path)
  end

  update_all(sql.join(',')) unless sql.blank?

  if [:mysql, :mysql2].include?(db_adapter)
    update_all("`level` = 0", "`level` IS NULL") if node.has_attribute?(:level)
    update_all("`path` = `slug`", "`path` IS NULL") if node.has_attribute?(:slug) && node.has_attribute?(:path)
  end
end

#denormalize_level_query ⇒ Object

sqlite3, postgresql



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# File 'lib/simple_nested_set/nested_set.rb', line 181

def denormalize_level_query
  aliaz = arel_table.as(:l)
  query = aliaz.project(aliaz[:id].count).
                where(aliaz[:lft].lt(arel_table[:lft])).
                where(aliaz[:rgt].gt(arel_table[:rgt]))
  query = [query.to_sql] + where_clauses.map { |clause| clause.gsub(arel_table.name, 'l') }
  "level = (#{query.join(' AND ')})"
end

#denormalize_path_query ⇒ Object

sqlite3, postgresql



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# File 'lib/simple_nested_set/nested_set.rb', line 191

def denormalize_path_query
  aliaz = arel_table.as(:l)
  query = aliaz.project(group_concat(db_adapter, :slug)).
                where(aliaz[:lft].lteq(arel_table[:lft])).
                where(aliaz[:rgt].gteq(arel_table[:rgt]))
  query = [query.to_sql] + where_clauses.map { |clause| clause.gsub(arel_table.name, 'l') }
  "path = (#{query.join(' AND ')})"
end

#init_as_node ⇒ Object

before validation set lft and rgt to the end of the tree



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# File 'lib/simple_nested_set/nested_set.rb', line 140

def init_as_node
  max_right = maximum(:rgt) || 0
  node.lft, node.rgt = max_right + 1, max_right + 2
end

#move_by_attributes(attributes) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 158

def move_by_attributes(attributes)
  Move::ByAttributes.new(node, attributes).perform
end

#move_to(target, position) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 168

def move_to(target, position)
  Move::ToTarget.new(node, target, position).perform
end

#move_to_path(path) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 162

def move_to_path(path)
  node.path, parent_path = path, path.split('/')[0..-2].join('/')
  parent = parent_path.empty? ? nil : node.nested_set.where(:path => parent_path).first
  node.move_to_child_of(parent)
end

#populate_associations(nodes) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 131

def populate_associations(nodes)
  node.children.target = nodes.select do |child|
    next unless child.parent_id == node.id
    child.nested_set.populate_associations(nodes)
    child.parent = node
  end
end

#prune_branch ⇒ Object

Prunes a branch off of the tree, shifting all of the elements on the right back to the left so the counts still work.



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# File 'lib/simple_nested_set/nested_set.rb', line 147

def prune_branch
  if node.rgt && node.lft
    transaction do
      diff = node.rgt - node.lft + 1
      delete_all(['lft > ? AND rgt < ?', node.lft, node.rgt])
      update_all(['lft = (lft - ?)', diff], ['lft >= ?', node.rgt])
      update_all(['rgt = (rgt - ?)', diff], ['rgt >= ?', node.rgt])
    end
  end
end

#rebuild_from_parents!(sort_order = :id) ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 176

def rebuild_from_parents!(sort_order = :id)
  Rebuild::FromParents.new.run(self, sort_order)
end

#rebuild_from_paths! ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 172

def rebuild_from_paths!
  Rebuild::FromPaths.new.run(self)
end

#reload ⇒ Object

reload nested set attributes



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# File 'lib/simple_nested_set/nested_set.rb', line 116

def reload
  columns  = [:parent_id, :lft, :rgt]
  columns << :level if node.has_attribute?(:level)
  columns << :path  if node.has_attribute?(:path)

  reloaded = unscoped { find(node.id, :select => columns) }
  node.instance_eval { @attributes.merge!(reloaded.instance_variable_get(:@attributes)) }
  node.parent = nil if node.parent_id.nil?
  node.children.reset
end

#same_scope?(other) ⇒ Boolean

Returns true if the node has the same scope as the given node

Returns:

  • (Boolean) 


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# File 'lib/simple_nested_set/nested_set.rb', line 111

def same_scope?(other)
  scope_names.all? { |scope| node.send(scope) == other.send(scope) }
end

#save! ⇒ Object 



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# File 'lib/simple_nested_set/nested_set.rb', line 42

def save!
  attributes = node.instance_variable_get(:@_nested_set_attributes) || {}
  node.instance_variable_set(:@_nested_set_attributes, nil)
  attributes.merge!(:parent_id => node.parent_id) if node.parent_id_changed?

  if self.class.move_after_save
    move_by_attributes(attributes) unless attributes.blank?
    denormalize!
  elsif attributes
    attributes.except(:parent_id).each do |key, value|
      node.update_attribute(key, value)
    end
  end
end