1 files changed, 114 insertions, 0 deletions
diff --git a/src/pybind/mgr/volumes/fs/operations/versions/op_sm.py b/src/pybind/mgr/volumes/fs/operations/versions/op_sm.py
new file mode 100644
index 000000000..1142600cb
--- /dev/null
+++ b/src/pybind/mgr/volumes/fs/operations/versions/op_sm.py
@@ -0,0 +1,114 @@
+import errno
+
+from typing import Dict
+
+from ...exception import OpSmException
+from .subvolume_attrs import SubvolumeTypes, SubvolumeStates, SubvolumeActions
+
+class TransitionKey(object):
+    def __init__(self, subvol_type, state, action_type):
+        self.transition_key = [subvol_type, state, action_type]
+
+    def __hash__(self):
+        return hash(tuple(self.transition_key))
+
+    def __eq__(self, other):
+        return self.transition_key == other.transition_key
+
+    def __neq__(self, other):
+        return not(self == other)
+
+class SubvolumeOpSm(object):
+    transition_table = {} # type: Dict
+
+    @staticmethod
+    def is_complete_state(state):
+        if not isinstance(state, SubvolumeStates):
+            raise OpSmException(-errno.EINVAL, "unknown state '{0}'".format(state))
+        return state == SubvolumeStates.STATE_COMPLETE
+
+    @staticmethod
+    def is_failed_state(state):
+        if not isinstance(state, SubvolumeStates):
+            raise OpSmException(-errno.EINVAL, "unknown state '{0}'".format(state))
+        return state == SubvolumeStates.STATE_FAILED or state == SubvolumeStates.STATE_CANCELED
+
+    @staticmethod
+    def is_init_state(stm_type, state):
+        if not isinstance(state, SubvolumeStates):
+            raise OpSmException(-errno.EINVAL, "unknown state '{0}'".format(state))
+        return state == SubvolumeOpSm.get_init_state(stm_type)
+
+    @staticmethod
+    def get_init_state(stm_type):
+        if not isinstance(stm_type, SubvolumeTypes):
+            raise OpSmException(-errno.EINVAL, "unknown state machine '{0}'".format(stm_type))
+        init_state =  SubvolumeOpSm.transition_table[TransitionKey(stm_type,
+                                                     SubvolumeStates.STATE_INIT,
+                                                     SubvolumeActions.ACTION_NONE)]
+        if not init_state:
+            raise OpSmException(-errno.ENOENT, "initial state for state machine '{0}' not found".format(stm_type))
+        return init_state
+
+    @staticmethod
+    def transition(stm_type, current_state, action):
+        if not isinstance(stm_type, SubvolumeTypes):
+            raise OpSmException(-errno.EINVAL, "unknown state machine '{0}'".format(stm_type))
+        if not isinstance(current_state, SubvolumeStates):
+            raise OpSmException(-errno.EINVAL, "unknown state '{0}'".format(current_state))
+        if not isinstance(action, SubvolumeActions):
+            raise OpSmException(-errno.EINVAL, "unknown action '{0}'".format(action))
+
+        transition = SubvolumeOpSm.transition_table[TransitionKey(stm_type, current_state, action)]
+        if not transition:
+            raise OpSmException(-errno.EINVAL, "invalid action '{0}' on current state {1} for state machine '{2}'".format(action, current_state, stm_type))
+
+        return transition
+
+SubvolumeOpSm.transition_table = {
+    # state transitions for state machine type TYPE_NORMAL
+    TransitionKey(SubvolumeTypes.TYPE_NORMAL,
+                  SubvolumeStates.STATE_INIT,
+                  SubvolumeActions.ACTION_NONE) : SubvolumeStates.STATE_COMPLETE,
+
+    TransitionKey(SubvolumeTypes.TYPE_NORMAL,
+                  SubvolumeStates.STATE_COMPLETE,
+                  SubvolumeActions.ACTION_RETAINED) : SubvolumeStates.STATE_RETAINED,
+
+    # state transitions for state machine type TYPE_CLONE
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_INIT,
+                  SubvolumeActions.ACTION_NONE) : SubvolumeStates.STATE_PENDING,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_PENDING,
+                  SubvolumeActions.ACTION_SUCCESS) : SubvolumeStates.STATE_INPROGRESS,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_PENDING,
+                  SubvolumeActions.ACTION_CANCELLED) : SubvolumeStates.STATE_CANCELED,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_INPROGRESS,
+                  SubvolumeActions.ACTION_SUCCESS) : SubvolumeStates.STATE_COMPLETE,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_INPROGRESS,
+                  SubvolumeActions.ACTION_CANCELLED) : SubvolumeStates.STATE_CANCELED,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_INPROGRESS,
+                  SubvolumeActions.ACTION_FAILED) : SubvolumeStates.STATE_FAILED,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_COMPLETE,
+                  SubvolumeActions.ACTION_RETAINED) : SubvolumeStates.STATE_RETAINED,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_CANCELED,
+                  SubvolumeActions.ACTION_RETAINED) : SubvolumeStates.STATE_RETAINED,
+
+    TransitionKey(SubvolumeTypes.TYPE_CLONE,
+                  SubvolumeStates.STATE_FAILED,
+                  SubvolumeActions.ACTION_RETAINED) : SubvolumeStates.STATE_RETAINED,
+}