FilesExpand file tree

 master

/

cache.py

Copy path

Blame

More file actions

Blame

More file actions

Latest commit

 

History

History

History

162 lines (129 loc) · 4.68 KB

 master

/

cache.py

Copy path

Top

File metadata and controls

• Code
• Blame

162 lines (129 loc) · 4.68 KB

Raw

Copy raw file

Download raw file

Open symbols panel

Edit and raw actions

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

import time

import os

import sys

import hashlib

import gc

import shutil

import platform

import errno

import logging

try:

import cPickle as pickle

except:

import pickle

from parso._compatibility import FileNotFoundError

LOG = logging.getLogger(__name__)

_PICKLE_VERSION = 30

"""

Version number (integer) for file system cache.

Increment this number when there are any incompatible changes in

the parser tree classes. For example, the following changes

are regarded as incompatible.

- A class name is changed.

- A class is moved to another module.

- A __slot__ of a class is changed.

"""

_VERSION_TAG = '%s-%s%s-%s' % (

platform.python_implementation(),

sys.version_info[0],

sys.version_info[1],

_PICKLE_VERSION

)

"""

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

"""

def _get_default_cache_path():

if platform.system().lower() == 'windows':

dir_ = os.path.join(os.getenv('LOCALAPPDATA') or '~', 'Parso', 'Parso')

elif platform.system().lower() == 'darwin':

dir_ = os.path.join('~', 'Library', 'Caches', 'Parso')

else:

dir_ = os.path.join(os.getenv('XDG_CACHE_HOME') or '~/.cache', 'parso')

return os.path.expanduser(dir_)

_default_cache_path = _get_default_cache_path()

"""

The path where the cache is stored.

On Linux, this defaults to ``~/.cache/parso/``, on OS X to

``~/Library/Caches/Parso/`` and on Windows to ``%LOCALAPPDATA%\\Parso\\Parso\\``.

On Linux, if environment variable ``$XDG_CACHE_HOME`` is set,

``$XDG_CACHE_HOME/parso`` is used instead of the default one.

"""

parser_cache = {}

class _NodeCacheItem(object):

def __init__(self, node, lines, change_time=None):

self.node = node

self.lines = lines

if change_time is None:

change_time = time.time()

self.change_time = change_time

def load_module(hashed_grammar, path, cache_path=None):

"""

Returns a module or None, if it fails.

"""

try:

p_time = os.path.getmtime(path)

except FileNotFoundError:

return None

try:

module_cache_item = parser_cache[hashed_grammar][path]

if p_time <= module_cache_item.change_time:

return module_cache_item.node

except KeyError:

return _load_from_file_system(hashed_grammar, path, p_time, cache_path=cache_path)

def _load_from_file_system(hashed_grammar, path, p_time, cache_path=None):

cache_path = _get_hashed_path(hashed_grammar, path, cache_path=cache_path)

try:

try:

if p_time > os.path.getmtime(cache_path):

# Cache is outdated

return None

except OSError as e:

if e.errno == errno.ENOENT:

# In Python 2 instead of an IOError here we get an OSError.

raise FileNotFoundError

else:

raise

with open(cache_path, 'rb') as f:

gc.disable()

try:

module_cache_item = pickle.load(f)

finally:

gc.enable()

except FileNotFoundError:

return None

else:

parser_cache.setdefault(hashed_grammar, {})[path] = module_cache_item

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

return module_cache_item.node

def save_module(hashed_grammar, path, module, lines, pickling=True, cache_path=None):

try:

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

except OSError:

p_time = None

pickling = False

item = _NodeCacheItem(module, lines, p_time)

parser_cache.setdefault(hashed_grammar, {})[path] = item

if pickling and path is not None:

_save_to_file_system(hashed_grammar, path, item, cache_path=cache_path)

def _save_to_file_system(hashed_grammar, path, item, cache_path=None):

with open(_get_hashed_path(hashed_grammar, path, cache_path=cache_path), 'wb') as f:

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

def clear_cache(cache_path=None):

if cache_path is None:

cache_path = _default_cache_path

shutil.rmtree(cache_path)

parser_cache.clear()

def _get_hashed_path(hashed_grammar, path, cache_path=None):

directory = _get_cache_directory_path(cache_path=cache_path)

file_hash = hashlib.sha256(path.encode("utf-8")).hexdigest()

return os.path.join(directory, '%s-%s.pkl' % (hashed_grammar, file_hash))

def _get_cache_directory_path(cache_path=None):

if cache_path is None:

cache_path = _default_cache_path

directory = os.path.join(cache_path, _VERSION_TAG)

if not os.path.exists(directory):

os.makedirs(directory)

return directory