Class: MetaWhere::Visitors::Predicate

Inherits:
Visitor
  • Object
show all
Defined in:
lib/meta_where/visitors/predicate.rb

Instance Attribute Summary

Attributes inherited from Visitor

#join_dependency, #tables

Class Method Summary collapse

Instance Method Summary collapse

Methods inherited from Visitor

#accept, #can_accept?, #get_table, #initialize

Constructor Details

This class inherits a constructor from MetaWhere::Visitors::Visitor

Class Method Details

.visitables ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 7

def self.visitables
  [Hash, Array, MetaWhere::Or, MetaWhere::And, MetaWhere::Not, MetaWhere::Condition, MetaWhere::Function]
end

Instance Method Details

#visit_Array(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 64

def visit_Array(o, parent)
  if o.first.is_a? String
    join_dependency.join_base.send(:sanitize_sql, o)
  else
    o.map {|e| accept(e, parent)}.flatten
  end
end

#visit_Hash(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 11

def visit_Hash(o, parent)
  parent ||= join_dependency.join_base
  parent = parent.name if parent.is_a? MetaWhere::JoinType
  table = tables[parent]
  predicates = o.map do |column, value|
    if value.is_a?(Hash)
      association = association_from_parent_and_column(parent, column)
      accept(value, association || column)
    elsif [MetaWhere::Condition, MetaWhere::And, MetaWhere::Or, MetaWhere::Not].include?(value.class)
      association = association_from_parent_and_column(parent, column)
      accept(value, association || column)
    elsif value.is_a?(Array) && !value.empty? && value.all? {|v| can_accept?(v)}
      association = association_from_parent_and_column(parent, column)
      value.map {|val| accept(val, association || column)}
    elsif (value.is_a?(ActiveRecord::Base) || array_of_activerecords(value)) &&
        reflection = parent.active_record.reflect_on_association(column.is_a?(MetaWhere::JoinType) ? column.name : column)
      accept_activerecord_values(column, value, parent, reflection)
    else
      if column.is_a?(MetaWhere::Column)
        method = column.method
        column = column.column
      else
        method = method_from_value(value)
      end

      if [String, Symbol].include?(column.class) && column.to_s.include?('.')
        table_name, column = column.to_s.split('.', 2)
        table = Arel::Table.new(table_name, :engine => parent.arel_engine)
      end

      unless valid_comparison_method?(method)
        raise ::ActiveRecord::StatementInvalid, "No comparison method named `#{method}` exists for column `#{column}`"
      end

      if attribute = attribute_from_column_and_table(column, table)
        attribute.send(method, args_for_predicate(value))
      else
        raise ::ActiveRecord::StatementInvalid, "No attribute named `#{column}` exists for table `#{table.name}`"
      end

    end
  end

  predicates.flatten!

  if predicates.size > 1
    first = predicates.shift
    Arel::Nodes::Grouping.new(predicates.inject(first) {|memo, expr| Arel::Nodes::And.new(memo, expr)})
  else
    predicates.first
  end
end

#visit_MetaWhere_And(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 76

def visit_MetaWhere_And(o, parent)
  accept(o.condition1, parent).and(accept(o.condition2, parent))
end

#visit_MetaWhere_Condition(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 84

def visit_MetaWhere_Condition(o, parent)
  table = tables[parent]

  unless attribute = attribute_from_column_and_table(o.column, table)
    raise ::ActiveRecord::StatementInvalid, "No attribute named `#{o.column}` exists for table `#{table.name}`"
  end

  unless valid_comparison_method?(o.method)
    raise ::ActiveRecord::StatementInvalid, "No comparison method named `#{o.method}` exists for column `#{o.column}`"
  end
  attribute.send(o.method, args_for_predicate(o.value))
end

#visit_MetaWhere_Function(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 97

def visit_MetaWhere_Function(o, parent)
  self.table = tables[parent]

  o.to_sqlliteral
end

#visit_MetaWhere_Not(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 80

def visit_MetaWhere_Not(o, parent)
  accept(o.expr, parent).not
end

#visit_MetaWhere_Or(o, parent) ⇒ Object 



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# File 'lib/meta_where/visitors/predicate.rb', line 72

def visit_MetaWhere_Or(o, parent)
  accept(o.condition1, parent).or(accept(o.condition2, parent))
end