sdk/platform-tools/systrace/catapult/telemetry/third_party/modulegraph/modulegraph/util.py

   1 from __future__ import absolute_import
   2
   3 import os
   4 import imp
   5 import sys
   6 import re
   7 import marshal
   8 import warnings
   9
  10 try:
  11     unicode
  12 except NameError:
  13     unicode = str
  14
  15
  16 if sys.version_info[0] == 2:
  17     from StringIO import StringIO as BytesIO
  18     from StringIO import StringIO
  19
  20 else:
  21     from io import BytesIO, StringIO
  22
  23
  24
  25 def imp_find_module(name, path=None):
  26     """
  27     same as imp.find_module, but handles dotted names
  28     """
  29     names = name.split('.')
  30     if path is not None:
  31         if isinstance(path, (str, unicode)):
  32             path = [os.path.realpath(path)]
  33     for name in names:
  34         result = imp.find_module(name, path)
  35         if result[0] is not None:
  36             result[0].close()
  37         path = [result[1]]
  38     return result
  39
  40 def _check_importer_for_path(name, path_item):
  41     try:
  42         importer = sys.path_importer_cache[path_item]
  43     except KeyError:
  44         for path_hook in sys.path_hooks:
  45             try:
  46                 importer = path_hook(path_item)
  47                 break
  48             except ImportError:
  49                 pass
  50         else:
  51             importer = None
  52         sys.path_importer_cache.setdefault(path_item, importer)
  53
  54
  55     if importer is None:
  56         try:
  57             return imp.find_module(name, [path_item])
  58         except ImportError:
  59             return None
  60     return importer.find_module(name)
  61
  62 def imp_walk(name):
  63     """
  64     yields namepart, tuple_or_importer for each path item
  65
  66     raise ImportError if a name can not be found.
  67     """
  68     warnings.warn("imp_walk will be removed in a future version", DeprecationWarning)
  69
  70     if name in sys.builtin_module_names:
  71         yield name, (None, None, ("", "", imp.C_BUILTIN))
  72         return
  73     paths = sys.path
  74     res = None
  75     for namepart in name.split('.'):
  76         for path_item in paths:
  77             res = _check_importer_for_path(namepart, path_item)
  78             if hasattr(res, 'load_module'):
  79                 if res.path.endswith('.py') or res.path.endswith('.pyw'):
  80                     fp = StringIO(res.get_source(namepart))
  81                     res = (fp, res.path, ('.py', 'rU', imp.PY_SOURCE))
  82                 elif res.path.endswith('.pyc') or res.path.endswith('.pyo'):
  83                     co  = res.get_code(namepart)
  84                     fp = BytesIO(imp.get_magic() + b'\0\0\0\0' + marshal.dumps(co))
  85                     res = (fp, res.path, ('.pyc', 'rb', imp.PY_COMPILED))
  86
  87                 else:
  88                     res = (None, loader.path, (os.path.splitext(loader.path)[-1], 'rb', imp.C_EXTENSION))
  89
  90                 break
  91             elif isinstance(res, tuple):
  92                 break
  93         else:
  94             break
  95
  96         yield namepart, res
  97         paths = [os.path.join(path_item, namepart)]
  98     else:
  99         return
 100
 101     raise ImportError('No module named %s' % (name,))
 102
 103
 104 cookie_re = re.compile(b"coding[:=]\s*([-\w.]+)")
 105 if sys.version_info[0] == 2:
 106     default_encoding = 'ascii'
 107 else:
 108     default_encoding = 'utf-8'
 109
 110 def guess_encoding(fp):
 111
 112     for i in range(2):
 113         ln = fp.readline()
 114
 115         m = cookie_re.search(ln)
 116         if m is not None:
 117             return m.group(1).decode('ascii')
 118
 119     return default_encoding