Module: Switchman::ActiveRecord::SpawnMethods

Defined in:
lib/switchman/active_record/spawn_methods.rb

Instance Method Summary collapse

Instance Method Details

#merge(r) ⇒ Object 



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# File 'lib/switchman/active_record/spawn_methods.rb', line 46

def merge(r)
  return self unless r
  return super unless r.is_a?(Relation)

  # have to figure out shard stuff *before* conditions are merged
  final_shard_value, final_primary_shard, final_shard_source_value = shard_values_for_merge(r)

  return super unless final_shard_source_value

  if !final_shard_value
    result = super
    result.shard_source_value = final_shard_source_value
    return result
  end

  return none if final_shard_value == []

  # change the primary shard if necessary before merging
  result = if primary_shard != final_primary_shard && r.primary_shard != final_primary_shard
             lhs = shard(final_primary_shard)
             r = r.shard(final_primary_shard)
             lhs.merge(r)
           elsif primary_shard != final_primary_shard
             lhs = shard(final_primary_shard)
             lhs.merge(r)
           elsif r.primary_shard != final_primary_shard
             r = r.shard(final_primary_shard)
             super(r)
           else
             super
           end

  result.shard_value = final_shard_value
  result.shard_source_value = final_shard_source_value

  result
end

#merge!(r) ⇒ Object 



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# File 'lib/switchman/active_record/spawn_methods.rb', line 84

def merge!(r)
  return super unless r.is_a?(::ActiveRecord::Relation)

  # have to figure out shard stuff *before* conditions are merged
  final_shard_value, final_primary_shard, final_shard_source_value = shard_values_for_merge(r)

  return super unless final_shard_source_value

  if !final_shard_value
    super
    self.shard_source_value = final_shard_source_value
    return self
  end

  return none! if final_shard_value == []

  # change the primary shard if necessary before merging
  if primary_shard != final_primary_shard && r.primary_shard != final_primary_shard
    shard!(final_primary_shard)
    r = r.shard(final_primary_shard)
    super(r)
  elsif primary_shard != final_primary_shard
    shard!(final_primary_shard)
    super(r)
  elsif r.primary_shard != final_primary_shard
    r = r.shard(final_primary_shard)
    super(r)
  else
    super
  end

  self.shard_value = final_shard_value
  self.shard_source_value = final_shard_source_value

  self
end

#shard_values_for_merge(r) ⇒ Object 



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# File 'lib/switchman/active_record/spawn_methods.rb', line 4

def shard_values_for_merge(r)
  if shard_value != r.shard_value
    if r.shard_source_value == :implicit
      final_shard_value = shard_value
      final_primary_shard = primary_shard
      final_shard_source_value = shard_source_value
    elsif shard_source_value == :implicit
      final_shard_value = r.shard_value
      final_primary_shard = r.primary_shard
      final_shard_source_value = r.shard_source_value
    else
      final_shard_source_value = [:explicit, :association].detect do |source_value|
        shard_source_value == source_value || r.shard_source_value == source_value
      end
      raise "unknown shard_source_value" unless final_shard_source_value

      # have to merge shard_value
      lhs_shard_value = all_shards
      rhs_shard_value = r.all_shards
      if (::ActiveRecord::Relation === lhs_shard_value &&
          ::ActiveRecord::Relation === rhs_shard_value)
        final_shard_value = lhs_shard_value.merge(rhs_shard_value)
        final_primary_shard = Shard.default
      else
        final_shard_value = lhs_shard_value.to_a & rhs_shard_value.to_a
        final_primary_shard = final_shard_value.first
        final_shard_value = final_shard_value.first if final_shard_value.length == 1
      end
    end
  elsif shard_source_value != r.shard_source_value
    final_shard_source_value = [:explicit, :association, :implicit].detect do |source_value|
      shard_source_value == source_value || r.shard_source_value == source_value
    end
    raise "unknown shard_source_value" unless final_shard_source_value
  else
    # nothing fancy
  end

  [final_shard_value, final_primary_shard, final_shard_source_value]
end