"""

This caching is very important for speed and memory optimizations. There's

nothing really spectacular, just some decorators. The following cache types are

available:

- module caching (`load_parser` and `save_parser`), which uses pickle and is

really important to assure low load times of modules like ``numpy``.

- ``time_cache`` can be used to cache something for just a limited time span,

which can be useful if there's user interaction and the user cannot react

faster than a certain time.

This module is one of the reasons why |jedi| is not thread-safe. As you can see

there are global variables, which are holding the cache information. Some of

these variables are being cleaned after every API usage.

"""

import time

import os

import sys

import json

import hashlib

import gc

import inspect

import shutil

import re

try:

import cPickle as pickle

except ImportError:

import pickle

from jedi import settings

from jedi import common

from jedi import debug

_time_caches = {}

# for fast_parser, should not be deleted

parser_cache = {}

class ParserCacheItem(object):

def __init__(self, parser, change_time=None):

self.parser = parser

if change_time is None:

change_time = time.time()

self.change_time = change_time

def clear_time_caches(delete_all=False):

""" Jedi caches many things, that should be completed after each completion

finishes.

:param delete_all: Deletes also the cache that is normally not deleted,

like parser cache, which is important for faster parsing.

"""

global _time_caches

if delete_all:

for cache in _time_caches.values():

cache.clear()

parser_cache.clear()

else:

# normally just kill the expired entries, not all

for tc in _time_caches.values():

# check time_cache for expired entries

for key, (t, value) in list(tc.items()):

if t < time.time():

# delete expired entries

del tc[key]

def time_cache(time_add_setting):

"""

s

This decorator works as follows: Call it with a setting and after that

use the function with a callable that returns the key.

But: This function is only called if the key is not available. After a

certain amount of time (`time_add_setting`) the cache is invalid.

"""

def _temp(key_func):

dct = {}

_time_caches[time_add_setting] = dct

def wrapper(*args, **kwargs):

generator = key_func(*args, **kwargs)

key = next(generator)

try:

expiry, value = dct[key]

if expiry > time.time():

return value

except KeyError:

pass

value = next(generator)

time_add = getattr(settings, time_add_setting)

if key is not None:

dct[key] = time.time() + time_add, value

return value

return wrapper

return _temp

@time_cache("call_signatures_validity")

def cache_call_signatures(evaluator, call, source, user_pos):

"""This function calculates the cache key."""

index = user_pos[0] - 1

lines = common.splitlines(source)

before_cursor = lines[index][:user_pos[1]]

other_lines = lines[call.start_pos[0]:index]

whole = '\n'.join(other_lines + [before_cursor])

before_bracket = re.match(r'.*\(', whole, re.DOTALL)

module_path = call.get_parent_until().path

yield None if module_path is None else (module_path, before_bracket, call.start_pos)

yield evaluator.eval_element(call)

def underscore_memoization(func):

"""

Decorator for methods::

class A(object):

def x(self):

if self._x:

self._x = 10

return self._x

Becomes::

class A(object):

@underscore_memoization

def x(self):

return 10

A now has an attribute ``_x`` written by this decorator.

"""

name = '_' + func.__name__

def wrapper(self):

try:

return getattr(self, name)

except AttributeError:

result = func(self)

if inspect.isgenerator(result):

result = list(result)

setattr(self, name, result)

return result

return wrapper

def memoize_method(method):

"""A normal memoize function."""

def wrapper(self, *args, **kwargs):

dct = self.__dict__.setdefault('_memoize_method_dct', {})

key = (args, frozenset(kwargs.items()))

try:

return dct[key]

except KeyError:

result = method(self, *args, **kwargs)

dct[key] = result

return result

return wrapper

def cache_star_import(func):

@time_cache("star_import_cache_validity")

def wrapper(self):

yield self.base # The cache key

yield func(self)

return wrapper

def _invalidate_star_import_cache_module(module, only_main=False):

""" Important if some new modules are being reparsed """

try:

t, modules = _time_caches['star_import_cache_validity'][module]

except KeyError:

pass

else:

del _time_caches['star_import_cache_validity'][module]

def invalidate_star_import_cache(path):

"""On success returns True."""

try:

parser_cache_item = parser_cache[path]

except KeyError:

pass

else:

_invalidate_star_import_cache_module(parser_cache_item.parser.module)

def load_parser(path):

"""

Returns the module or None, if it fails.

"""

p_time = os.path.getmtime(path) if path else None

try:

parser_cache_item = parser_cache[path]

if not path or p_time <= parser_cache_item.change_time:

return parser_cache_item.parser

else:

# In case there is already a module cached and this module

# has to be reparsed, we also need to invalidate the import

# caches.

_invalidate_star_import_cache_module(parser_cache_item.parser.module)

except KeyError:

if settings.use_filesystem_cache:

return ParserPickling.load_parser(path, p_time)

def save_parser(path, parser, pickling=True):

try:

p_time = None if path is None else os.path.getmtime(path)

except OSError:

p_time = None

pickling = False

item = ParserCacheItem(parser, p_time)

parser_cache[path] = item

if settings.use_filesystem_cache and pickling:

ParserPickling.save_parser(path, item)

class ParserPickling(object):

version = 24

"""

Version number (integer) for file system cache.

Increment this number when there are any incompatible changes in

parser representation classes. For example, the following changes

are regarded as incompatible.

- Class name is changed.

- Class is moved to another module.

- Defined slot of the class is changed.

"""

def __init__(self):

self.__index = None

self.py_tag = 'cpython-%s%s' % sys.version_info[:2]

"""

Short name for distinguish Python implementations and versions.

It's like `sys.implementation.cache_tag` but for Python < 3.3

we generate something similar. See:

http://docs.python.org/3/library/sys.html#sys.implementation

.. todo:: Detect interpreter (e.g., PyPy).

"""

def load_parser(self, path, original_changed_time):

try:

pickle_changed_time = self._index[path]

except KeyError:

return None

if original_changed_time is not None \

and pickle_changed_time < original_changed_time:

# the pickle file is outdated

return None

with open(self._get_hashed_path(path), 'rb') as f:

try:

gc.disable()

parser_cache_item = pickle.load(f)

finally:

gc.enable()

debug.dbg('pickle loaded: %s', path)

parser_cache[path] = parser_cache_item

return parser_cache_item.parser

def save_parser(self, path, parser_cache_item):

self.__index = None

try:

files = self._index

except KeyError:

files = {}

self._index = files

with open(self._get_hashed_path(path), 'wb') as f:

pickle.dump(parser_cache_item, f, pickle.HIGHEST_PROTOCOL)

files[path] = parser_cache_item.change_time

self._flush_index()

@property

def _index(self):

if self.__index is None:

try:

with open(self._get_path('index.json')) as f:

data = json.load(f)

except (IOError, ValueError):

self.__index = {}

else:

# 0 means version is not defined (= always delete cache):

if data.get('version', 0) != self.version:

self.clear_cache()

self.__index = {}

else:

self.__index = data['index']

return self.__index

def _remove_old_modules(self):

# TODO use

change = False

if change:

self._flush_index(self)

self._index # reload index

def _flush_index(self):

data = {'version': self.version, 'index': self._index}

with open(self._get_path('index.json'), 'w') as f:

json.dump(data, f)

self.__index = None

def clear_cache(self):

shutil.rmtree(self._cache_directory())

def _get_hashed_path(self, path):

return self._get_path('%s.pkl' % hashlib.md5(path.encode("utf-8")).hexdigest())

def _get_path(self, file):

dir = self._cache_directory()

if not os.path.exists(dir):

os.makedirs(dir)

return os.path.join(dir, file)

def _cache_directory(self):

return os.path.join(settings.cache_directory, self.py_tag)

# is a singleton

ParserPickling = ParserPickling()