| """ |
| - the popular ``_memoize_default`` works like a typical memoize and returns the |
| default otherwise. |
| - ``CachedMetaClass`` uses ``_memoize_default`` to do the same with classes. |
| """ |
| from functools import wraps |
|
|
| from jedi import debug |
|
|
| _NO_DEFAULT = object() |
| _RECURSION_SENTINEL = object() |
|
|
|
|
| def _memoize_default(default=_NO_DEFAULT, inference_state_is_first_arg=False, |
| second_arg_is_inference_state=False): |
| """ This is a typical memoization decorator, BUT there is one difference: |
| To prevent recursion it sets defaults. |
| |
| Preventing recursion is in this case the much bigger use than speed. I |
| don't think, that there is a big speed difference, but there are many cases |
| where recursion could happen (think about a = b; b = a). |
| """ |
| def func(function): |
| def wrapper(obj, *args, **kwargs): |
| |
| if inference_state_is_first_arg: |
| cache = obj.memoize_cache |
| elif second_arg_is_inference_state: |
| cache = args[0].memoize_cache |
| else: |
| cache = obj.inference_state.memoize_cache |
|
|
| try: |
| memo = cache[function] |
| except KeyError: |
| cache[function] = memo = {} |
|
|
| key = (obj, args, frozenset(kwargs.items())) |
| if key in memo: |
| return memo[key] |
| else: |
| if default is not _NO_DEFAULT: |
| memo[key] = default |
| rv = function(obj, *args, **kwargs) |
| memo[key] = rv |
| return rv |
| return wrapper |
|
|
| return func |
|
|
|
|
| def inference_state_function_cache(default=_NO_DEFAULT): |
| def decorator(func): |
| return _memoize_default(default=default, inference_state_is_first_arg=True)(func) |
|
|
| return decorator |
|
|
|
|
| def inference_state_method_cache(default=_NO_DEFAULT): |
| def decorator(func): |
| return _memoize_default(default=default)(func) |
|
|
| return decorator |
|
|
|
|
| def inference_state_as_method_param_cache(): |
| def decorator(call): |
| return _memoize_default(second_arg_is_inference_state=True)(call) |
|
|
| return decorator |
|
|
|
|
| class CachedMetaClass(type): |
| """ |
| This is basically almost the same than the decorator above, it just caches |
| class initializations. Either you do it this way or with decorators, but |
| with decorators you lose class access (isinstance, etc). |
| """ |
| @inference_state_as_method_param_cache() |
| def __call__(self, *args, **kwargs): |
| return super().__call__(*args, **kwargs) |
|
|
|
|
| def inference_state_method_generator_cache(): |
| """ |
| This is a special memoizer. It memoizes generators and also checks for |
| recursion errors and returns no further iterator elemends in that case. |
| """ |
| def func(function): |
| @wraps(function) |
| def wrapper(obj, *args, **kwargs): |
| cache = obj.inference_state.memoize_cache |
| try: |
| memo = cache[function] |
| except KeyError: |
| cache[function] = memo = {} |
|
|
| key = (obj, args, frozenset(kwargs.items())) |
|
|
| if key in memo: |
| actual_generator, cached_lst = memo[key] |
| else: |
| actual_generator = function(obj, *args, **kwargs) |
| cached_lst = [] |
| memo[key] = actual_generator, cached_lst |
|
|
| i = 0 |
| while True: |
| try: |
| next_element = cached_lst[i] |
| if next_element is _RECURSION_SENTINEL: |
| debug.warning('Found a generator recursion for %s' % obj) |
| |
| return |
| except IndexError: |
| cached_lst.append(_RECURSION_SENTINEL) |
| next_element = next(actual_generator, None) |
| if next_element is None: |
| cached_lst.pop() |
| return |
| cached_lst[-1] = next_element |
| yield next_element |
| i += 1 |
| return wrapper |
|
|
| return func |
|
|