Class: Hotdog::Expression::BinaryExpressionNode

Inherits:
ExpressionNode show all
Defined in:
lib/hotdog/expression/semantics.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(op, left, right) ⇒ BinaryExpressionNode

Returns a new instance of BinaryExpressionNode.



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# File 'lib/hotdog/expression/semantics.rb', line 122

def initialize(op, left, right)
  case (op || "or").to_s
  when "&&", "&", "AND", "and"
    @op = :AND
  when ",", "||", "|", "OR", "or"
    @op = :OR
  when "^", "XOR", "xor"
    @op = :XOR
  else
    raise(SyntaxError.new("unknown binary operator: #{op.inspect}"))
  end
  @left = left
  @right = right
end

Instance Attribute Details

#left ⇒ Object (readonly)

Returns the value of attribute left.



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# File 'lib/hotdog/expression/semantics.rb', line 120

def left
  @left
end

#op ⇒ Object (readonly)

Returns the value of attribute op.



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# File 'lib/hotdog/expression/semantics.rb', line 120

def op
  @op
end

#right ⇒ Object (readonly)

Returns the value of attribute right.



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# File 'lib/hotdog/expression/semantics.rb', line 120

def right
  @right
end

Instance Method Details

#==(other) ⇒ Object 



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# File 'lib/hotdog/expression/semantics.rb', line 284

def ==(other)
  self.class === other and @op == other.op and @left == other.left and @right == other.right
end

#dump(options = {}) ⇒ Object 



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# File 'lib/hotdog/expression/semantics.rb', line 288

def dump(options={})
  {left: @left.dump(options), binary_op: @op.to_s, right: @right.dump(options)}
end

#evaluate(environment, options = {}) ⇒ Object 



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# File 'lib/hotdog/expression/semantics.rb', line 137

def evaluate(environment, options={})
  case @op
  when :AND
    left_values = @left.evaluate(environment, options).tap do |values|
      environment.logger.debug("lhs: #{values.length} value(s)")
    end
    if left_values.empty?
      []
    else
      right_values = @right.evaluate(environment, options).tap do |values|
        environment.logger.debug("rhs: #{values.length} value(s)")
      end
      if right_values.empty?
        []
      else
        # workaround for "too many terms in compound SELECT"
        min, max = environment.execute("SELECT MIN(id), MAX(id) FROM hosts LIMIT 1;").first.to_a
        (min / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2)).upto(max / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2)).flat_map { |i|
          range = (((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2) * i)...(((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2) * (i + 1))
          left_selected = left_values.select { |n| range === n }
          right_selected = right_values.select { |n| range === n }
          q = "SELECT id FROM hosts " \
                "WHERE ? <= id AND id < ? AND ( id IN (%s) AND id IN (%s) );"
          environment.execute(q % [left_selected.map { "?" }.join(", "), right_selected.map { "?" }.join(", ")], [range.first, range.last] + left_selected + right_selected).map { |row| row.first }
        }.tap do |values|
          environment.logger.debug("lhs AND rhs: #{values.length} value(s)")
        end
      end
    end
  when :OR
    left_values = @left.evaluate(environment, options).tap do |values|
      environment.logger.debug("lhs: #{values.length} value(s)")
    end
    right_values = @right.evaluate(environment, options).tap do |values|
      environment.logger.debug("rhs: #{values.length} value(s)")
    end
    if left_values.empty?
      right_values
    else
      if right_values.empty?
        []
      else
        # workaround for "too many terms in compound SELECT"
        min, max = environment.execute("SELECT MIN(id), MAX(id) FROM hosts LIMIT 1;").first.to_a
        (min / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2)).upto(max / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2)).flat_map { |i|
          range = (((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2) * i)...(((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 2) * (i + 1))
          left_selected = left_values.select { |n| range === n }
          right_selected = right_values.select { |n| range === n }
          q = "SELECT id FROM hosts " \
                "WHERE ? <= id AND id < ? AND ( id IN (%s) OR id IN (%s) );"
          environment.execute(q % [left_selected.map { "?" }.join(", "), right_selected.map { "?" }.join(", ")], [range.first, range.last] + left_selected + right_selected).map { |row| row.first }
        }.tap do |values|
          environment.logger.debug("lhs OR rhs: #{values.length} value(s)")
        end
      end
    end
  when :XOR
    left_values = @left.evaluate(environment, options).tap do |values|
      environment.logger.debug("lhs: #{values.length} value(s)")
    end
    right_values = @right.evaluate(environment, options).tap do |values|
      environment.logger.debug("rhs: #{values.length} value(s)")
    end
    if left_values.empty?
      right_values
    else
      if right_values.empty?
        []
      else
        # workaround for "too many terms in compound SELECT"
        min, max = environment.execute("SELECT MIN(id), MAX(id) FROM hosts LIMIT 1;").first.to_a
        (min / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 4)).upto(max / ((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 4)).flat_map { |i|
          range = (((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 4) * i)...(((SQLITE_LIMIT_COMPOUND_SELECT - 2) / 4) * (i + 1))
          left_selected = left_values.select { |n| range === n }
          right_selected = right_values.select { |n| range === n }
          q = "SELECT id FROM hosts " \
                "WHERE ? <= id AND id < ? AND NOT (id IN (%s) AND id IN (%s)) AND ( id IN (%s) OR id IN (%s) );"
          lq = left_selected.map { "?" }.join(", ")
          rq = right_selected.map { "?" }.join(", ")
          environment.execute(q % [lq, rq, lq, rq], [range.first, range.last] + left_selected + right_selected + left_selected + right_selected).map { |row| row.first }
        }.tap do |values|
          environment.logger.debug("lhs XOR rhs: #{values.length} value(s)")
        end
      end
    end
  else
    []
  end
end

#optimize(options = {}) ⇒ Object 



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# File 'lib/hotdog/expression/semantics.rb', line 227

def optimize(options={})
  @left = @left.optimize(options)
  @right = @right.optimize(options)
  case op
  when :AND
    case left
    when EverythingNode
      right
    when NothingNode
      left
    else
      if left == right
        left
      else
        optimize1(options)
      end
    end
  when :OR
    case left
    when EverythingNode
      left
    when NothingNode
      right
    else
      if left == right
        left
      else
        if MultinaryExpressionNode === left
          if left.op == op
            left.merge(right, fallback: self)
          else
            optimize1(options)
          end
        else
          if MultinaryExpressionNode === right
            if right.op == op
              right.merge(left, fallback: self)
            else
              optimize1(options)
            end
          else
            MultinaryExpressionNode.new(op, [left, right], fallback: self)
          end
        end
      end
    end
  when :XOR
    if left == right
      []
    else
      optimize1(options)
    end
  else
    self
  end
end