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Old 05-18-2011, 12:25 PM
Ales Kozumplik
 
Default dispatch: implement method of saving/restoring all steps scheduling.

Imagine this scenario, steps A, B and C are scheduled to be executed in
that order. Based on a user's choice A decides to skip_step(B) and then
the user presses "back" during C. This will take us back to A, but
previously the state of step B would stay 'skipped'. Instead, it is
desirable upon going back to have all the steps in the same scheduling
state as they were when the original step was first entered.

This patch addresses that by having each step store a dictionary of
scheduling changes that happened during that step (a mapping from a step
name to the tuple (from_state, to_state). It is therefore always possible
to reconstruct the original state.

Unittests included.
---
pyanaconda/dispatch.py | 95 ++++++++++++++++++++++-------
tests/pyanaconda_test/dispatch_test.py | 104 +++++++++++++++++++++++++-------
2 files changed, 154 insertions(+), 45 deletions(-)

diff --git a/pyanaconda/dispatch.py b/pyanaconda/dispatch.py
index df03442..6033398 100644
--- a/pyanaconda/dispatch.py
+++ b/pyanaconda/dispatch.py
@@ -82,12 +82,14 @@ class Step(object):
user interface object is told to handle the step (i.e. indirect
step).
"""
+ self._changes = {} # tracks changes (FROM, TO) in scheduling of other steps
self.name = name
self.target = target # None for dynamic target (e.g. gui view)
self._sched = self.SCHED_UNSCHEDULED

- def _reschedule(self, to_sched):
- new_sched = self.sched_state_machine[self._sched][to_sched]
+ def _reschedule(self, to_sched, current_step):
+ s_from = self.sched
+ new_sched = self.sched_state_machine[self.sched][to_sched]
if new_sched is False:
raise errors.DispatchError(
"Can not reschedule step '%s' from '%s' to '%s'" %
@@ -95,16 +97,25 @@ class Step(object):
self.namesched(self._sched),
self.namesched(to_sched)))
self._sched = to_sched
+ if current_step:
+ current_step.record_history(self, s_from, self.sched)
+
+ @property
+ def changes(self):
+ return self._changes
+
+ def clear_changes(self):
+ self._changes = {}

@property
def direct(self):
return self.target is not None

- def done(self):
- self._reschedule(self.SCHED_DONE)
+ def done(self, current_step):
+ return self._reschedule(self.SCHED_DONE, current_step)

- def request(self):
- self._reschedule(self.SCHED_REQUESTED)
+ def request(self, current_step):
+ return self._reschedule(self.SCHED_REQUESTED, current_step)

def namesched(self, sched):
return {
@@ -115,16 +126,29 @@ class Step(object):
self.SCHED_DONE : "done"
}[sched]

+ def record_history(self, step, s_from, s_to):
+ """ Stores information about scheduling changes into self.
+
+ step is a step where scheduling changed from s_from to s_to. the
+ self object in this method should be the currently executing object.
+ """
+ if step.name in self._changes:
+ s_from = self._changes[step.name][0]
+ self._changes[step.name] = (s_from, s_to)
+
+ def revert_sched(self, s_from, s_to):
+ assert(self.sched == s_to)
+ self._sched = s_from
+
@property
def sched(self):
return self._sched

- def schedule(self):
- self._reschedule(self.SCHED_SCHEDULED)
-
- def skip(self):
- self._reschedule(self.SCHED_SKIPPED)
+ def schedule(self, current_step):
+ return self._reschedule(self.SCHED_SCHEDULED, current_step)

+ def skip(self, current_step):
+ return self._reschedule(self.SCHED_SKIPPED, current_step)

class Dispatcher(object):

@@ -132,6 +156,7 @@ class Dispatcher(object):
self.anaconda = anaconda
self.anaconda.dir = DISPATCH_FORWARD
self.step = None # name of the current step
+ self.stop = False
# step dictionary mapping step names to step objects
self.steps = indexed_dict.IndexedDict()
# Note that not only a subset of the steps is executed for a particular
@@ -190,8 +215,34 @@ class Dispatcher(object):
self.steps[name] = Step(name, target)

def _advance_step(self):
- i = self._step_index()
- self.step = self.steps[i + 1].name
+ if self.step is None:
+ # initialization
+ log.info("dispatch: resetting to the first step.")
+ self.step = self.steps[0].name
+ elif self._step_index() < len(self.steps) - 1:
+ i = self._step_index()
+ if self.dir == DISPATCH_BACK:
+ # revert whatever changed in the current step
+ self._revert_scheduling(self.step)
+ self.step = self.steps[i + self.dir].name
+ if self.dir == DISPATCH_BACK:
+ # revert whatever changed in the step we moved back to
+ self._revert_scheduling(self.step)
+ else:
+ # advancing from the last step
+ self.step = "_invalid_"
+ self.stop = True
+
+ def _current_step(self):
+ if self.step:
+ return self.steps[self.step]
+ return None
+
+ def _revert_scheduling(self, reverted_step):
+ """ Revert scheduling changes that happened during reverted_step. """
+ for (step, (s_from, s_to)) in self.steps[reverted_step].changes.items():
+ self.steps[step].revert_sched(s_from, s_to)
+ self.steps[reverted_step].clear_changes()

def _step_index(self):
return self.steps.index(self.step)
@@ -208,7 +259,7 @@ class Dispatcher(object):
self.anaconda.dir = dir

def done_steps(self, *steps):
- map(lambda s: self.steps[s].done(), steps)
+ changes = map(lambda s: self.steps[s].done(self._current_step()), steps)

def go_back(self):
"""
@@ -234,14 +285,14 @@ class Dispatcher(object):
return False

def request_steps(self, *steps):
- map(lambda s: self.steps[s].request(), steps)
+ changes = map(lambda s: self.steps[s].request(self._current_step()), steps)

def run(self):
self.anaconda.intf.run(self.anaconda)
log.info("dispatch: finished.")

def schedule_steps(self, *steps):
- map(lambda s: self.steps[s].schedule(), steps)
+ changes = map(lambda s: self.steps[s].schedule(self._current_step()), steps)

def step_disabled(self, step):
""" True if step is not yet scheduled to be run or will never be run
@@ -256,24 +307,20 @@ class Dispatcher(object):
Step.SCHED_DONE]

def skip_steps(self, *steps):
- map(lambda s: self.steps[s].skip(), steps)
+ changes = map(lambda s: self.steps[s].skip(self._current_step()), steps)

def step_is_direct(self, step):
return self.steps[step].direct

def dispatch(self):
- total_steps = len(self.steps)
- if self.step == None:
- log.info("dispatch: resetting to the first step.")
- self.step = self.steps[0].name
- else:
+ if self.step:
log.info("dispatch: leaving (%d) step %s" %
(self.dir, self.step))
self.done_steps(self.step)
- self._advance_step()
+ self._advance_step()

while True:
- if self._step_index() >= total_steps:
+ if self.stop:
# installation has proceeded beyond the last step: finished
self.anaconda.intf.shutdown()
return
diff --git a/tests/pyanaconda_test/dispatch_test.py b/tests/pyanaconda_test/dispatch_test.py
index afb2e88..61148f5 100644
--- a/tests/pyanaconda_test/dispatch_test.py
+++ b/tests/pyanaconda_test/dispatch_test.py
@@ -15,11 +15,11 @@ class StepTest(mock.TestCase):
from pyanaconda.dispatch import Step
from pyanaconda.errors import DispatchError
s = Step("a_step")
- s.schedule()
- s.request()
- s.done()
+ s.schedule(None)
+ s.request(None)
+ s.done(None)
self.assertEquals(s.sched, Step.SCHED_DONE)
- self.assertRaises(DispatchError, s.skip)
+ self.assertRaises(DispatchError, s.skip, None)

def instantiation_test(self):
from pyanaconda.dispatch import Step
@@ -39,45 +39,84 @@ class StepTest(mock.TestCase):
from pyanaconda.dispatch import Step
from pyanaconda.errors import DispatchError
s = Step("a_step")
- s._reschedule(Step.SCHED_UNSCHEDULED)
+ s._reschedule(Step.SCHED_UNSCHEDULED, None)
self.assertEqual(s.sched, Step.SCHED_UNSCHEDULED)
- s._reschedule(Step.SCHED_SCHEDULED)
+ s._reschedule(Step.SCHED_SCHEDULED, None)
self.assertEqual(s.sched, Step.SCHED_SCHEDULED)
- s._reschedule(Step.SCHED_REQUESTED)
+ s._reschedule(Step.SCHED_REQUESTED, None)
self.assertEqual(s.sched, Step.SCHED_REQUESTED)
- self.assertRaises(DispatchError, s._reschedule, Step.SCHED_SKIPPED)
- self.assertRaises(DispatchError, s._reschedule, Step.SCHED_UNSCHEDULED)
- s._reschedule(Step.SCHED_DONE)
- self.assertEqual(s.sched, Step.SCHED_DONE)
+ self.assertRaises(DispatchError, s._reschedule, Step.SCHED_SKIPPED, None)
+ self.assertRaises(DispatchError, s._reschedule, Step.SCHED_UNSCHEDULED, None)
+ s._reschedule(Step.SCHED_DONE, None)
+ self.assertEqual(s.sched, Step.SCHED_DONE, None)

s = Step("another_step")
- s._reschedule(Step.SCHED_SKIPPED)
+ s._reschedule(Step.SCHED_SKIPPED, None)
self.assertEqual(s.sched, Step.SCHED_SKIPPED)
- self.assertRaises(DispatchError, s._reschedule, Step.SCHED_SCHEDULED)
- self.assertRaises(DispatchError, s._reschedule, Step.SCHED_REQUESTED)
- self.assertRaises(DispatchError, s._reschedule, Step.SCHED_DONE)
+ self.assertRaises(DispatchError, s._reschedule, Step.SCHED_SCHEDULED, None)
+ self.assertRaises(DispatchError, s._reschedule, Step.SCHED_REQUESTED, None)
+ self.assertRaises(DispatchError, s._reschedule, Step.SCHED_DONE, None)

def request_test(self):
from pyanaconda.dispatch import Step
from pyanaconda.errors import DispatchError
s = Step("a_step")
- s.request()
- self.assertRaises(DispatchError, s.skip)
+ s.request(None)
+ self.assertRaises(DispatchError, s.skip, None)

def schedule_test(self):
from pyanaconda.dispatch import Step
s = Step("a_step")
- s.schedule()
+ s.schedule(None)
self.assertEquals(s.sched, Step.SCHED_SCHEDULED)

def skip_test(self):
from pyanaconda.dispatch import Step
from pyanaconda.errors import DispatchError
s = Step("a_step")
- s.skip()
+ s.skip(None)
self.assertEquals(s.sched, Step.SCHED_SKIPPED)
- self.assertRaises(DispatchError, s.done)
- self.assertRaises(DispatchError, s.request)
+ self.assertRaises(DispatchError, s.done, None)
+ self.assertRaises(DispatchError, s.request, None)
+
+ def record_history_test(self):
+ from pyanaconda.dispatch import Step
+ s = Step("first_step")
+ self.assertDictEqual(s.changes, {})
+
+ s2 = Step("second_step")
+ s.record_history(s2, Step.SCHED_UNSCHEDULED, Step.SCHED_SCHEDULED)
+ self.assertDictEqual(
+ s.changes,
+ {'second_step' : (Step.SCHED_UNSCHEDULED, Step.SCHED_SCHEDULED)})
+ s.record_history(s2, Step.SCHED_SCHEDULED, Step.SCHED_DONE)
+ self.assertDictEqual(
+ s.changes,
+ {'second_step' : (Step.SCHED_UNSCHEDULED, Step.SCHED_DONE)})
+
+ def revert_sched_test(self):
+ from pyanaconda.dispatch import Step
+ s = Step("first_step")
+ s.request(None)
+ s.revert_sched(Step.SCHED_UNSCHEDULED, Step.SCHED_REQUESTED)
+ self.assertEqual(s.sched, Step.SCHED_UNSCHEDULED)
+ s.request(None)
+ self.assertRaises(AssertionError, s.revert_sched, Step.SCHED_SKIPPED,
+ Step.SCHED_UNSCHEDULED)
+
+ def tracking_test(self):
+ """ Tests that reschedule correctly registers steps to revert """
+ from pyanaconda.dispatch import Step
+ s1 = Step("first_step")
+ s2 = Step("second_step")
+ s = Step("current_step")
+ s1.schedule(s)
+ s2.schedule(s)
+ s2.request(s)
+ self.assertDictEqual(
+ s.changes,
+ {"first_step" : (Step.SCHED_UNSCHEDULED, Step.SCHED_SCHEDULED),
+ "second_step" : (Step.SCHED_UNSCHEDULED, Step.SCHED_REQUESTED)})

class DispatchTest(mock.TestCase):
def setUp(self):
@@ -131,3 +170,26 @@ class DispatchTest(mock.TestCase):
self.assertFalse(d.step_enabled("betanag"))
self.assertFalse(d.step_enabled("complete"))
self.assertTrue(d.step_enabled("filtertype"))
+
+ def track_scheduling_test(self):
+ from pyanaconda.dispatch import Step
+ d = self._getDispatcher()
+ d.schedule_steps("betanag", "filtertype", "filter")
+ d.step = "betanag"
+ # tested through the request_steps
+ d.request_steps("filtertype", "filter")
+ self.assertDictEqual(
+ d.steps[d.step].changes,
+ {"filtertype" : (Step.SCHED_SCHEDULED, Step.SCHED_REQUESTED),
+ "filter" : (Step.SCHED_SCHEDULED, Step.SCHED_REQUESTED)})
+
+ def revert_scheduling_test(self):
+ from pyanaconda.dispatch import Step
+ d = self._getDispatcher()
+ d.schedule_steps("betanag", "filtertype", "filter")
+ d.step = "betanag"
+ d.request_steps("filtertype", "filter")
+ d._revert_scheduling("betanag")
+ self.assertEqual(d.steps["filtertype"].sched, Step.SCHED_SCHEDULED)
+ self.assertEqual(d.steps["filter"].sched, Step.SCHED_SCHEDULED)
+ self.assertDictEqual(d.steps[d.step].changes, {})
--
1.7.3.3

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