WIP add docstrings to state.py
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shep/state.py
115
shep/state.py
@ -8,7 +8,17 @@ from shep.error import (
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class State:
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"""State is an in-memory bitmasked state store for key-value pairs, or even just keys alone.
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A State is comprised of a number of atomic state bits, and zero or more aliases that represent unique combinations of these bits.
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The State object will enforce that duplicate states cannot exist. It will also enforce that all alias states are composed of valid atomic states.
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:param bits: Number of atomic states that this State object will represent (i.e. number of bits).
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:type bits: int
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:param logger: Standard library logging instance to output to
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:type logger: logging.Logger
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"""
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def __init__(self, bits, logger=None):
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self.__bits = bits
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self.__limit = (1 << bits) - 1
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@ -21,6 +31,7 @@ class State:
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self.__contents = {}
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# return true if v is a single-bit state
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def __is_pure(self, v):
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if v == 0:
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return True
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@ -32,12 +43,14 @@ class State:
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return c == v
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# validates a state name and return its canonical representation
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def __check_name_valid(self, k):
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if not k.isalpha():
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raise ValueError('only alpha')
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return k.upper()
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# enforces name validity, aswell as name uniqueness
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def __check_name(self, k):
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k = self.__check_name_valid(k)
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@ -49,6 +62,7 @@ class State:
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return k
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# enforces state value validity and uniqueness
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def __check_valid(self, v):
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v = self.__check_value_typ(v)
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if self.__reverse.get(v):
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@ -56,22 +70,26 @@ class State:
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return v
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# enforces state value within bit limit of instantiation
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def __check_limit(self, v):
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if v > self.__limit:
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raise OverflowError(v)
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return v
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# enforces state value validity, uniqueness and value limit
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def __check_value(self, v):
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v = self.__check_valid(v)
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self.__check_limit(v)
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return v
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# enforces state value validity
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def __check_value_typ(self, v):
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return int(v)
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# enforces state value validity within the currently registered states (number of add calls vs number of bits in instantiation).
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def __check_value_cursor(self, v):
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v = self.__check_value_typ(v)
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if v > 1 << self.__c:
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@ -79,17 +97,20 @@ class State:
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return v
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# set a bit for state of the given key
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def __set(self, k, v):
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setattr(self, k, v)
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self.__reverse[v] = k
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self.__c += 1
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# check validity of key to register state for
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def __check_key(self, item):
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if self.__keys_reverse.get(item) != None:
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raise StateItemExists(item)
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# adds a new key to the state store
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def __add_state_list(self, state, item):
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if self.__keys.get(state) == None:
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self.__keys[state] = []
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@ -97,6 +118,9 @@ class State:
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self.__keys_reverse[item] = state
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# Get index of a key for a given state.
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# A key should only ever exist in one state.
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# A failed lookup should indicate a mistake on the caller part, (it may also indicate corruption, but probanbly impossible to tell the difference)
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def __state_list_index(self, item, state_list):
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idx = -1
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try:
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@ -110,6 +134,11 @@ class State:
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return idx
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# Add a state to the store.
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#
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# :param k: State name
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# :type k: str
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# :raises shep.error.StateExists: State name is already registered
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def add(self, k):
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v = 1 << self.__c
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k = self.__check_name(k)
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@ -117,6 +146,16 @@ class State:
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self.__set(k, v)
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# Add an alias for a combination of states in the store.
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#
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# State aggregates may be provided as comma separated values or as a single (or'd) integer value.
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#|
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# :param k: Alias name
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# :type k: str
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# :param *args: One or more states to aggregate for this alias.
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# :type *args: int or list of ints
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# :raises StateInvalid: Attempt to create alias for one or more atomic states that do not exist.
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# :raises ValueError: Attempt to use bit value as alias
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def alias(self, k, *args):
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k = self.__check_name(k)
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v = 0
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@ -128,6 +167,10 @@ class State:
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self.__set(k, v)
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# Return list of all unique atomic and alias states.
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#
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# :rtype: list of ints
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# :return: states
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def all(self):
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l = []
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for k in dir(self):
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@ -140,6 +183,13 @@ class State:
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return l
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# Retrieve that string representation of the state attribute represented by the given state integer value.
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#
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# :param v: State integer
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# :type v: int
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# :raises StateInvalid: State corresponding to given integer not found
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# :rtype: str
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# :return: State name
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def name(self, v):
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if v == None or v == 0:
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return 'NEW'
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@ -149,11 +199,30 @@ class State:
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return k
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# Retrieve the real state integer value corresponding to an attribute name.
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#
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# :param k: Attribute name
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# :type k: str
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# :raises ValueError: Invalid attribute name
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# :raises AttributeError: Attribute not found
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# :rtype: int
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# :return: Numeric state value
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def from_name(self, k):
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k = self.__check_name_valid(k)
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return getattr(self, k)
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# Match against all stored states.
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#
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# If pure is set, only match against the single atomic state will be returned.
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#
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# :param v: Integer state to match
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# :type v: int
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# :param pure: Match only pure states
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# :type pure: bool
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# :raises KeyError: Unknown state
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# :rtype: tuple
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# :return: 0: Alias that input resolves to, 1: list of atomic states that matches the state
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def match(self, v, pure=False):
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alias = None
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if not pure:
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@ -172,8 +241,24 @@ class State:
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return (alias, r,)
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def put(self, key, state=None, contents=None, force=False):
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# Add a key to an existing state.
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#
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# If no state it specified, the default state attribute "NEW" will be used.
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#
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# Contents may be supplied as value to pair with the given key. Contents may be changed later by calling the `replace` method.
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#
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# :param key: Content key to add
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# :type key: str
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# :param state: Initial state for the put. If not given, initial state will be NEW
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# :type state: int
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# :param contents: Contents to associate with key. A valie of None should be recognized as an undefined value as opposed to a zero-length value throughout any backend
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# :type contents: str
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# :raises StateItemExists: Content key has already been added
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# :raises StateInvalid: Given state has not been registered
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# :rtype: integer
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# :return: Resulting state that key is put under (should match the input state)
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def put(self, key, state=None, contents=None):
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if state == None:
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state = self.NEW
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elif self.__reverse.get(state) == None:
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@ -190,6 +275,16 @@ class State:
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return state
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# Move a given content key from one state to another.
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#
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# :param key: Key to move
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# :type key: str
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# :param to_state: Numeric state to move to (may be atomic or alias)
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# :type to_state: integer
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# :raises StateItemNotFound: Given key has not been registered
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# :raises StateInvalid: Given state has not been registered
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# :rtype: integer
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# :return: Resulting state from move (should match the state given as input)
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def move(self, key, to_state):
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current_state = self.__keys_reverse.get(key)
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if current_state == None:
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@ -202,6 +297,7 @@ class State:
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return self.__move(key, current_state, to_state)
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# implementation for state move that ensures integrity of keys and states.
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def __move(self, key, from_state, to_state):
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current_state_list = self.__keys.get(from_state)
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if current_state_list == None:
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@ -217,9 +313,20 @@ class State:
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current_state_list.pop(idx)
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return to_state
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def set(self, key, or_state, content=None):
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# Set a partial state bit. May result in an alias state being triggered.
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#
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# :param key: Content key to modify state for
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# :type key: str
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# :param or_state: Atomic stat to add
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# :type or_state: int
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# :raises ValueError: State is not a single bit state
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# :raises StateItemNotFound: Content key is not registered
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# :raises StateInvalid: Resulting state after addition of atomic state is unknown
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# :rtype: int
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# :returns: Resulting state
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def set(self, key, or_state):
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if not self.__is_pure(or_state):
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raise ValueError('can only apply using single bit states')
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