Class: Oplogjam::Operators::IntermediateIndex

Inherits:
Intermediate
  • Object
show all
Defined in:
lib/oplogjam/operators/intermediate_index.rb

Instance Attribute Summary

Attributes inherited from Intermediate

#path, #tree

Instance Method Summary collapse

Methods inherited from Intermediate

#initialize, #nodes, #populate, #populate_field, #populate_index, #set, #set_field, #set_index

Constructor Details

This class inherits a constructor from Oplogjam::Operators::Intermediate

Instance Method Details

#index ⇒ Object 



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# File 'lib/oplogjam/operators/intermediate_index.rb', line 38

def index
  Integer(path.last, 10)
end

#parent_path ⇒ Object 



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# File 'lib/oplogjam/operators/intermediate_index.rb', line 34

def parent_path
  path[0...-1]
end

#update(column) ⇒ Object 



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# File 'lib/oplogjam/operators/intermediate_index.rb', line 6

def update(column)
  # Now for a not-so-fun bit!
  #
  # As this is a numeric index, it might either be an index into an existing array or a numeric field name on an
  # object.
  #
  # If it is an index into an array then we need to ensure that all prior indexes down to 0 are either set or null.
  # If it is anything else, it should be an empty object. In order to figure that out, we need to look at the parent
  # path and switch based on its type.
  filled_array_column = (0...index).inject(column) { |subject, i|
    prior_path = parent_path + [i.to_s]

    subject.set(prior_path, Sequel.function(:coalesce, column[prior_path], NULL))
  }

  populated_column = Sequel.pg_jsonb_op(
    Sequel.case(
      {
        ARRAY_TYPE => filled_array_column.set(path, Sequel.function(:coalesce, filled_array_column[path], EMPTY_OBJECT))
      },
      column.set(path, Sequel.function(:coalesce, column[path], EMPTY_OBJECT)),
      column[parent_path].typeof
    )
  )

  nodes.inject(populated_column, &UPDATE_COLUMN)
end