yast/yast-storage-ng

# Copyright (c) [2019] SUSE LLC
#
# All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify it
# under the terms of version 2 of the GNU General Public License as published
# by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
# more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, contact SUSE LLC.
#
# To contact SUSE LLC about this file by physical or electronic mail, you may
# find current contact information at www.suse.com.

module Y2Partitioner
  module Actions
    module Controllers
      # Mixin offering method to query all available block devices from a devicegraph
      #
      # In this context, an available device means that it is not currently being
      # used by another device (e.g., RAID, LVM VG, etc). In case the device is
      # directly formatted, it is also considered as available if the filesystem is
      # not mounted.
      module AvailableDevices
        # Method to query all available block devices from a devicegraph
        #
        # A block can be given to filter the list of available devices.
        #
        # @param devicegraph [Y2Storage::Devicegraph]
        # @yield [Y2Storage::BlkDevice]
        #
        # @return [Array<Y2Storage::BlkDevice>]
        def available_devices(devicegraph, &block)
          finder = Finder.new(devicegraph)

          finder.available_devices(&block)
        end

        # Helper class to find available devices
        class Finder
          # Constructor
          #
          # @param devicegraph [Y2Storage::Devicegraph]
          def initialize(devicegraph)
            @devicegraph = devicegraph
          end

          # All available devices
          #
          # A block can be given to filter the list of available devices.
          #
          # @see #available_device?
          #
          # @yield [Y2Storage::BlkDevice]
          # @return [Array<Y2Storage::BlkDevice>]
          def available_devices(&block)
            devices = all_devices.select { |d| available_device?(d) }

            return devices unless block_given?

            devices.select { |d| block.call(d) }
          end

          private

          # @return [Controllers::BtrfsDevices]
          attr_reader :devicegraph

          # All block devices
          #
          # @return [Array<Y2Storage::BlkDevice>]
          def all_devices
            devicegraph.blk_devices
          end

          # Whether the given device is available
          #
          # A device is available when it is not used by another device (e.g., RAID),
          # its filesystem is not mounted, it is not partitioned and it is not a
          # zero-sized device.
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def available_device?(device)
            !used?(device) &&
              !formatted_and_mounted?(device) &&
              !partitions?(device) &&
              !extended_partition?(device) &&
              !zero_size?(device)
          end

          # Whether the device is already in use (e.g., as LVM PV, as RAID disk, etc)
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def used?(device)
            device.component_of.any?
          end

          # Whether the device is formatted and mounted
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def formatted_and_mounted?(device)
            device.formatted? && device.filesystem.mount_point
          end

          # Whether the device has partitions
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def partitions?(device)
            device.respond_to?(:partitions) && device.partitions.any?
          end

          # Whether the device is an extended partition
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def extended_partition?(device)
            device.is?(:partition) && device.type.is?(:extended)
          end

          # Whether the device is a zero-sized device
          #
          # @param device [Y2Storage::BlkDevice]
          # @return [Boolean]
          def zero_size?(device)
            device.size.zero?
          end
        end
      end
    end
  end
end