Class: CreatedId::IdRange

Inherits:
ActiveRecord::Base
  • Object
show all
Defined in:
lib/created_id/id_range.rb

Overview

This model stores the id ranges for other models by the hour. It is not meant to be accessed directly.

Class Method Summary collapse

Class Method Details

.id_range(klass, time) ⇒ Array<Integer>

Get the minimum and maximum ids for a model created in a given hour. This method is used in indexing the ranges.

Parameters:

  • klass (Class) —

    The class to get the id range for.

  • time (Time) —

    The hour to get the id range for.

Returns:

  • (Array<Integer>) —

    The minimum and maximum ids for the class created in the given hour.



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# File 'lib/created_id/id_range.rb', line 67

def id_range(klass, time)
  klass = klass.base_class
  hour = CreatedId.coerce_hour(time)
  next_hour = hour + 3600

  finder = klass.unscoped.where(created_at: (hour...next_hour))

  prev_id = CreatedId::IdRange.min_id(klass, hour)
  if prev_id
    finder = finder.where(klass.arel_table[:id].gt(prev_id)) if prev_id > 0
  end

  next_id = CreatedId::IdRange.min_id(klass, next_hour + 3600)
  if next_id && (prev_id.nil? || next_id > prev_id)
    finder = finder.where(klass.arel_table[:id].lt(next_id))
  end

  [finder.minimum(:id), finder.maximum(:id)]
end

.max_id(klass, time, allow_nil: false) ⇒ Integer?

Get the maximum id for a class created in a given hour.

Parameters:

  • klass (Class) —

    The class to get the maximum id for.

  • time (Time) —

    The hour to get the maximum id for.

  • allow_nil (Boolean) (defaults to: false) —

    Whether to allow a nil value to be returned. If this is false, then the method will return the maximum possible id for the id column.

Returns:

  • (Integer, nil) —

    The maximum id for the class created in the given hour.



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# File 'lib/created_id/id_range.rb', line 44

def max_id(klass, time, allow_nil: false)
  return nil if time.nil? && allow_nil

  id = for_class(klass).created_after(CreatedId.coerce_hour(time)).order(hour: :asc).first&.max_id

  if id.nil? && !allow_nil
    col_limit = klass.columns.detect { |c| c.name == klass.primary_key }.limit
    id = if col_limit && col_limit > 0
      ((256**col_limit) / 2) - 1
    else
      klass.base_class.unscoped.maximum(:id).to_i
    end
  end

  id
end

.min_id(klass, time, allow_nil: false) ⇒ Integer?

Get the minimum id for a class created in a given hour.

Parameters:

  • klass (Class) —

    The class to get the minimum id for.

  • time (Time) —

    The hour to get the minimum id for.

  • allow_nil (Boolean) (defaults to: false) —

    Whether to allow a nil value to be returned. If this is false, then the method will return 0 if no value is found.

Returns:

  • (Integer, nil) —

    The minimum id for the class created in the given hour.



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# File 'lib/created_id/id_range.rb', line 29

def min_id(klass, time, allow_nil: false)
  return nil if time.nil? && allow_nil

  id = for_class(klass).created_before(time).order(hour: :desc).first&.min_id
  id ||= 0 unless allow_nil
  id
end

.save_created_id(klass, time, min_id, max_id) ⇒ void

This method returns an undefined value.

Save the minimum and maximum ids for a class created in a given hour.

Parameters:

  • klass (Class) —

    The class to save the id range for.

  • time (Time) —

    The hour to save the id range for.

  • min_id (Integer) —

    The minimum id for the class created in the given hour.

  • max_id (Integer) —

    The maximum id for the class created in the given hour.



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# File 'lib/created_id/id_range.rb', line 94

def save_created_id(klass, time, min_id, max_id)
  record = find_or_initialize_by(class_name: klass.base_class.name, hour: CreatedId.coerce_hour(time))
  record.min_id = min_id
  record.max_id = max_id
  record.save!
end