path: root/storage/deviceaction.py

# deviceaction.py
# Device modification action classes for anaconda's storage configuration
# module.
#
# Copyright (C) 2009  Red Hat, Inc.
#
# This copyrighted material is made available to anyone wishing to use,
# modify, copy, or redistribute it subject to the terms and conditions of
# the GNU General Public License v.2, or (at your option) any later version.
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY expressed or implied, including the implied warranties 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, write to the
# Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.  Any Red Hat trademarks that are incorporated in the
# source code or documentation are not subject to the GNU General Public
# License and may only be used or replicated with the express permission of
# Red Hat, Inc.
#
# Red Hat Author(s): Dave Lehman <dlehman@redhat.com>
#
""" action.py

"""
from devices import StorageDevice
from errors import *

import gettext
_ = lambda x: gettext.ldgettext("anaconda", x)

import logging
log = logging.getLogger("storage")


""" The values are just hints as to the ordering.

    Eg: fsmod and devmod ordering depends on the mod (shrink -v- grow)
"""
ACTION_TYPE_NONE = 0
ACTION_TYPE_DESTROY = 1000
ACTION_TYPE_RESIZE = 500
ACTION_TYPE_MIGRATE = 250
ACTION_TYPE_CREATE = 100

action_strings = {ACTION_TYPE_NONE: "None",
                  ACTION_TYPE_DESTROY: "Destroy",
                  ACTION_TYPE_RESIZE: "Resize",
                  ACTION_TYPE_MIGRATE: "Migrate",
                  ACTION_TYPE_CREATE: "Create"}

ACTION_OBJECT_NONE = 0
ACTION_OBJECT_FORMAT = 1
ACTION_OBJECT_DEVICE = 2

object_strings = {ACTION_OBJECT_NONE: "None",
                  ACTION_OBJECT_FORMAT: "Format",
                  ACTION_OBJECT_DEVICE: "Device"}

RESIZE_SHRINK = 88
RESIZE_GROW = 89

resize_strings = {RESIZE_SHRINK: "Shrink",
                  RESIZE_GROW: "Grow"}

class DeviceAction(object):
    """ An action that will be carried out in the future on a Device.

        These classes represent actions to be performed on devices or
        filesystems.

        The operand Device instance will be modified according to the
        action, but no changes will be made to the underlying device or
        filesystem until the DeviceAction instance's execute method is
        called. The DeviceAction instance's cancel method should reverse
        any modifications made to the Device instance's attributes.

        If the Device instance represents a pre-existing device, the
        constructor should call any methods or set any attributes that the
        action will eventually change. Device/DeviceFormat classes should verify
        that the requested modifications are reasonable and raise an
        exception if not.

        Only one action of any given type/object pair can exist for any
        given device at any given time. This is enforced by the
        DeviceTree.

        Basic usage:

            a = DeviceAction(dev)
            a.execute()

            OR

            a = DeviceAction(dev)
            a.cancel()


        XXX should we back up the device with a deep copy for forcibly
            cancelling actions?

            The downside is that we lose any checking or verification that
            would get done when resetting the Device instance's attributes to
            their original values.

            The upside is that we would be guaranteed to achieve a total
            reversal. No chance of, eg: resizes ending up altering Device
            size due to rounding or other miscalculation.
"""
    type = ACTION_TYPE_NONE
    obj = ACTION_OBJECT_NONE

    def __init__(self, device):
        if not isinstance(device, StorageDevice):
            raise ValueError("arg 1 must be a StorageDevice instance")
        self.device = device
        #self._backup = deepcopy(device)

    def execute(self):
        """ perform the action """
        pass

    def cancel(self):
        """ cancel the action """
        pass

    def isDestroy(self):
        return self.type == ACTION_TYPE_DESTROY

    def isCreate(self):
        return self.type == ACTION_TYPE_CREATE

    def isMigrate(self):
        return self.type == ACTION_TYPE_MIGRATE

    def isResize(self):
        return self.type == ACTION_TYPE_RESIZE

    def isShrink(self):
        return (self.type == ACTION_TYPE_RESIZE and self.dir == RESIZE_SHRINK)

    def isGrow(self):
        return (self.type == ACTION_TYPE_RESIZE and self.dir == RESIZE_GROW)

    def isDevice(self):
        return self.obj == ACTION_OBJECT_DEVICE

    def isFormat(self):
        return self.obj == ACTION_OBJECT_FORMAT

    def __str__(self):
        s = "%s %s" % (action_strings[self.type], object_strings[self.obj])
        if self.isResize():
            s += " (%s)" % resize_strings[self.dir]
        if self.isFormat():
            if self.format:
                fmt_type = self.format.type
            else:
                fmt_type = None
            s += " %s on" % fmt_type
        if self.isMigrate():
            pass
        s += " %s (%s)" % (self.device.name, self.device.type)
        return s

class ActionCreateDevice(DeviceAction):
    """ Action representing the creation of a new device. """
    type = ACTION_TYPE_CREATE
    obj = ACTION_OBJECT_DEVICE

    def __init__(self, device):
        # FIXME: assert device.fs is None
        DeviceAction.__init__(self, device)

    def execute(self):
        self.device.create()


class ActionDestroyDevice(DeviceAction):
    """ An action representing the deletion of an existing device. """
    type = ACTION_TYPE_DESTROY
    obj = ACTION_OBJECT_DEVICE

    def __init__(self, device):
        # XXX should we insist that device.fs be None?
        DeviceAction.__init__(self, device)

    def execute(self):
        self.device.destroy()


class ActionResizeDevice(DeviceAction):
    """ An action representing the resizing of an existing device. """
    type = ACTION_TYPE_RESIZE
    obj = ACTION_OBJECT_DEVICE

    def __init__(self, device, newsize):
        if device.size == newsize:
            raise ValueError("new size same as old size")

        DeviceAction.__init__(self, device)
        if newsize > device.size:
            self.dir = RESIZE_GROW
        else:
            self.dir = RESIZE_SHRINK
        self.origsize = device.size
        self.device.size = newsize

    def execute(self):
        self.device.resize()

    def cancel(self):
        self.device.size = self.origsize


class ActionCreateFormat(DeviceAction):
    """ An action representing creation of a new filesystem. """
    type = ACTION_TYPE_CREATE
    obj = ACTION_OBJECT_FORMAT

    def __init__(self, device, format):
        DeviceAction.__init__(self, device)
        # should we insist that device.format be None?
        # (indicative of ActionDestroyFormat having been instantiated)
        self.origFormat = device.format
        self.device.teardownFormat()
        self.device.format = format

    def execute(self):
        # XXX we should set partition type flag as needed
        #     - or should that be in the CreateDevice action?
        self.device.setup()
        self.device.format.create(device=self.device.path,
                                  options=self.device.formatArgs)

    def cancel(self):
        self.device.format = self.origFormat

    @property
    def format(self):
        return self.device.format


class ActionDestroyFormat(DeviceAction):
    """ An action representing the removal of an existing filesystem.

        XXX this seems unnecessary
    """
    type = ACTION_TYPE_DESTROY
    obj = ACTION_OBJECT_FORMAT

    def __init__(self, device):
        DeviceAction.__init__(self, device)
        self.origFormat = device.format
        if device.format and device.format.status:
            device.format.teardown()
        self.device.format = None

    def execute(self):
        """ wipe the filesystem signature from the device """
        #self.device.destroyFormat()
        if self.origFormat:
            self.device.setup()
            self.origFormat.destroy()

    def cancel(self):
        self.device.format = self.origFormat

    @property
    def format(self):
        return self.origFormat


class ActionResizeFormat(DeviceAction):
    """ An action representing the resizing of an existing filesystem.

        XXX Do we even want to support resizing of a filesystem without
            also resizing the device it resides on?
    """
    type = ACTION_TYPE_RESIZE
    obj = ACTION_OBJECT_FORMAT

    def __init__(self, device, newsize):
        if device.size == newsize:
            raise ValueError("new size same as old size")

        DeviceAction.__init__(self, device)
        if newsize > device.format.size:
            self.dir = RESIZE_GROW
        else:
            self.dir = RESIZE_SHRINK
        self.device.format.setSize(newsize)

    def execute(self):
        self.device.format.resize()

    def cancel(self):
        self.device.format.setSize(None)