PR cleanup according to comments.

IPython/core/completer.py

@@ -1,1270 +1,1270 b''
 # encoding: utf-8
 """Word completion for IPython.
 
 This module is a fork of the rlcompleter module in the Python standard
 library.  The original enhancements made to rlcompleter have been sent
 upstream and were accepted as of Python 2.3, but we need a lot more
 functionality specific to IPython, so this module will continue to live as an
 IPython-specific utility.
 
 Original rlcompleter documentation:
 
 This requires the latest extension to the readline module (the
 completes keywords, built-ins and globals in __main__; when completing
 NAME.NAME..., it evaluates (!) the expression up to the last dot and
 completes its attributes.
 
 It's very cool to do "import string" type "string.", hit the
 completion key (twice), and see the list of names defined by the
 string module!
 
 Tip: to use the tab key as the completion key, call
 
     readline.parse_and_bind("tab: complete")
 
 Notes:
 
 - Exceptions raised by the completer function are *ignored* (and
   generally cause the completion to fail).  This is a feature -- since
   readline sets the tty device in raw (or cbreak) mode, printing a
   traceback wouldn't work well without some complicated hoopla to save,
   reset and restore the tty state.
 
 - The evaluation of the NAME.NAME... form may cause arbitrary
   application defined code to be executed if an object with a
   ``__getattr__`` hook is found.  Since it is the responsibility of the
   application (or the user) to enable this feature, I consider this an
   acceptable risk.  More complicated expressions (e.g. function calls or
   indexing operations) are *not* evaluated.
 
 - GNU readline is also used by the built-in functions input() and
   raw_input(), and thus these also benefit/suffer from the completer
   features.  Clearly an interactive application can benefit by
   specifying its own completer function and using raw_input() for all
   its input.
 
 - When the original stdin is not a tty device, GNU readline is never
   used, and this module (and the readline module) are silently inactive.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 #
 # Some of this code originated from rlcompleter in the Python standard library
 # Copyright (C) 2001 Python Software Foundation, www.python.org
 
 from __future__ import print_function
 
 import __main__
 import glob
 import inspect
 import itertools
 import keyword
 import os
 import re
 import sys
 import unicodedata
 import string
 
 from traitlets.config.configurable import Configurable
 from IPython.core.error import TryNext
 from IPython.core.inputsplitter import ESC_MAGIC
 from IPython.core.latex_symbols import latex_symbols, reverse_latex_symbol
 from IPython.utils import generics
 from IPython.utils.decorators import undoc
 from IPython.utils.dir2 import dir2, get_real_method
 from IPython.utils.process import arg_split
 from IPython.utils.py3compat import builtin_mod, string_types, PY3, cast_unicode_py2
 from traitlets import Bool, Enum, observe
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # Public API
 __all__ = ['Completer','IPCompleter']
 
 if sys.platform == 'win32':
     PROTECTABLES = ' '
 else:
     PROTECTABLES = ' ()[]{}?=\\|;:\'#*"^&'
 
 
 #-----------------------------------------------------------------------------
 # Main functions and classes
 #-----------------------------------------------------------------------------
 
 def has_open_quotes(s):
     """Return whether a string has open quotes.
 
     This simply counts whether the number of quote characters of either type in
     the string is odd.
 
     Returns
     -------
     If there is an open quote, the quote character is returned.  Else, return
     False.
     """
     # We check " first, then ', so complex cases with nested quotes will get
     # the " to take precedence.
     if s.count('"') % 2:
         return '"'
     elif s.count("'") % 2:
         return "'"
     else:
         return False
 
 
 def protect_filename(s):
     """Escape a string to protect certain characters."""
     if set(s) & set(PROTECTABLES):
         if sys.platform == "win32":
             return '"' + s + '"'
         else:
-            return "".join("\\" + c if c in PROTECTABLES else c for c in s)
+            return "".join(("\\" + c if c in PROTECTABLES else c) for c in s)
     else:
         return s
 
 
 def expand_user(path):
     """Expand '~'-style usernames in strings.
 
     This is similar to :func:`os.path.expanduser`, but it computes and returns
     extra information that will be useful if the input was being used in
     computing completions, and you wish to return the completions with the
     original '~' instead of its expanded value.
 
     Parameters
     ----------
     path : str
       String to be expanded.  If no ~ is present, the output is the same as the
       input.
 
     Returns
     -------
     newpath : str
       Result of ~ expansion in the input path.
     tilde_expand : bool
       Whether any expansion was performed or not.
     tilde_val : str
       The value that ~ was replaced with.
     """
     # Default values
     tilde_expand = False
     tilde_val = ''
     newpath = path
 
     if path.startswith('~'):
         tilde_expand = True
         rest = len(path)-1
         newpath = os.path.expanduser(path)
         if rest:
             tilde_val = newpath[:-rest]
         else:
             tilde_val = newpath
 
     return newpath, tilde_expand, tilde_val
 
 
 def compress_user(path, tilde_expand, tilde_val):
     """Does the opposite of expand_user, with its outputs.
     """
     if tilde_expand:
         return path.replace(tilde_val, '~')
     else:
         return path
 
 
 def completions_sorting_key(word):
     """key for sorting completions
 
     This does several things:
 
     - Lowercase all completions, so they are sorted alphabetically with
       upper and lower case words mingled
     - Demote any completions starting with underscores to the end
     - Insert any %magic and %%cellmagic completions in the alphabetical order
       by their name
     """
     # Case insensitive sort
     word = word.lower()
 
     prio1, prio2 = 0, 0
 
     if word.startswith('__'):
         prio1 = 2
     elif word.startswith('_'):
         prio1 = 1
 
     if word.endswith('='):
         prio1 = -1
 
     if word.startswith('%%'):
         # If there's another % in there, this is something else, so leave it alone
         if not "%" in word[2:]:
             word = word[2:]
             prio2 = 2
     elif word.startswith('%'):
         if not "%" in word[1:]:
             word = word[1:]
             prio2 = 1
 
     return prio1, word, prio2
 
 
 @undoc
 class Bunch(object): pass
 
 
 DELIMS = ' \t\n`!@#$^&*()=+[{]}\\|;:\'",<>?'
 GREEDY_DELIMS = ' =\r\n'
 
 
 class CompletionSplitter(object):
     """An object to split an input line in a manner similar to readline.
 
     By having our own implementation, we can expose readline-like completion in
     a uniform manner to all frontends.  This object only needs to be given the
     line of text to be split and the cursor position on said line, and it
     returns the 'word' to be completed on at the cursor after splitting the
     entire line.
 
     What characters are used as splitting delimiters can be controlled by
     setting the `delims` attribute (this is a property that internally
     automatically builds the necessary regular expression)"""
 
     # Private interface
 
     # A string of delimiter characters.  The default value makes sense for
     # IPython's most typical usage patterns.
     _delims = DELIMS
 
     # The expression (a normal string) to be compiled into a regular expression
     # for actual splitting.  We store it as an attribute mostly for ease of
     # debugging, since this type of code can be so tricky to debug.
     _delim_expr = None
 
     # The regular expression that does the actual splitting
     _delim_re = None
 
     def __init__(self, delims=None):
         delims = CompletionSplitter._delims if delims is None else delims
         self.delims = delims
 
     @property
     def delims(self):
         """Return the string of delimiter characters."""
         return self._delims
 
     @delims.setter
     def delims(self, delims):
         """Set the delimiters for line splitting."""
         expr = '[' + ''.join('\\'+ c for c in delims) + ']'
         self._delim_re = re.compile(expr)
         self._delims = delims
         self._delim_expr = expr
 
     def split_line(self, line, cursor_pos=None):
         """Split a line of text with a cursor at the given position.
         """
         l = line if cursor_pos is None else line[:cursor_pos]
         return self._delim_re.split(l)[-1]
 
 
 class Completer(Configurable):
 
     greedy = Bool(False,
         help="""Activate greedy completion
         PENDING DEPRECTION. this is now mostly taken care of with Jedi.
 
         This will enable completion on elements of lists, results of function calls, etc.,
         but can be unsafe because the code is actually evaluated on TAB.
         """
     ).tag(config=True)
     
 
     def __init__(self, namespace=None, global_namespace=None, **kwargs):
         """Create a new completer for the command line.
 
         Completer(namespace=ns, global_namespace=ns2) -> completer instance.
 
         If unspecified, the default namespace where completions are performed
         is __main__ (technically, __main__.__dict__). Namespaces should be
         given as dictionaries.
 
         An optional second namespace can be given.  This allows the completer
         to handle cases where both the local and global scopes need to be
         distinguished.
 
         Completer instances should be used as the completion mechanism of
         readline via the set_completer() call:
 
         readline.set_completer(Completer(my_namespace).complete)
         """
 
         # Don't bind to namespace quite yet, but flag whether the user wants a
         # specific namespace or to use __main__.__dict__. This will allow us
         # to bind to __main__.__dict__ at completion time, not now.
         if namespace is None:
             self.use_main_ns = 1
         else:
             self.use_main_ns = 0
             self.namespace = namespace
 
         # The global namespace, if given, can be bound directly
         if global_namespace is None:
             self.global_namespace = {}
         else:
             self.global_namespace = global_namespace
 
         super(Completer, self).__init__(**kwargs)
 
     def complete(self, text, state):
         """Return the next possible completion for 'text'.
 
         This is called successively with state == 0, 1, 2, ... until it
         returns None.  The completion should begin with 'text'.
 
         """
         if self.use_main_ns:
             self.namespace = __main__.__dict__
 
         if state == 0:
             if "." in text:
                 self.matches = self.attr_matches(text)
             else:
                 self.matches = self.global_matches(text)
         try:
             return self.matches[state]
         except IndexError:
             return None
 
     def global_matches(self, text):
         """Compute matches when text is a simple name.
 
         Return a list of all keywords, built-in functions and names currently
         defined in self.namespace or self.global_namespace that match.
 
         """
         matches = []
         match_append = matches.append
         n = len(text)
         for lst in [keyword.kwlist,
                     builtin_mod.__dict__.keys(),
                     self.namespace.keys(),
                     self.global_namespace.keys()]:
             for word in lst:
                 if word[:n] == text and word != "__builtins__":
                     match_append(word)
         return [cast_unicode_py2(m) for m in matches]
 
     def attr_matches(self, text):
         """Compute matches when text contains a dot.
 
         Assuming the text is of the form NAME.NAME....[NAME], and is
         evaluatable in self.namespace or self.global_namespace, it will be
         evaluated and its attributes (as revealed by dir()) are used as
         possible completions.  (For class instances, class members are are
         also considered.)
 
         WARNING: this can still invoke arbitrary C code, if an object
         with a __getattr__ hook is evaluated.
 
         """
 
         # Another option, seems to work great. Catches things like ''.<tab>
         m = re.match(r"(\S+(\.\w+)*)\.(\w*)$", text)
     
         if m:
             expr, attr = m.group(1, 3)
         elif self.greedy:
             m2 = re.match(r"(.+)\.(\w*)$", self.line_buffer)
             if not m2:
                 return []
             expr, attr = m2.group(1,2)
         else:
             return []
     
         try:
             obj = eval(expr, self.namespace)
         except:
             try:
                 obj = eval(expr, self.global_namespace)
             except:
                 return []
 
         if self.limit_to__all__ and hasattr(obj, '__all__'):
             words = get__all__entries(obj)
         else: 
             words = dir2(obj)
 
         try:
             words = generics.complete_object(obj, words)
         except TryNext:
             pass
         except Exception:
             # Silence errors from completion function
             #raise # dbg
             pass
         # Build match list to return
         n = len(attr)
         return [u"%s.%s" % (expr, w) for w in words if w[:n] == attr ]
 
 
 def get__all__entries(obj):
     """returns the strings in the __all__ attribute"""
     try:
         words = getattr(obj, '__all__')
     except:
         return []
     
     return [cast_unicode_py2(w) for w in words if isinstance(w, string_types)]
 
 
 def match_dict_keys(keys, prefix, delims):
     """Used by dict_key_matches, matching the prefix to a list of keys"""
     if not prefix:
         return None, 0, [repr(k) for k in keys
                       if isinstance(k, (string_types, bytes))]
     quote_match = re.search('["\']', prefix)
     quote = quote_match.group()
     try:
         prefix_str = eval(prefix + quote, {})
     except Exception:
         return None, 0, []
 
     pattern = '[^' + ''.join('\\' + c for c in delims) + ']*$'
     token_match = re.search(pattern, prefix, re.UNICODE)
     token_start = token_match.start()
     token_prefix = token_match.group()
 
     # TODO: support bytes in Py3k
     matched = []
     for key in keys:
         try:
             if not key.startswith(prefix_str):
                 continue
         except (AttributeError, TypeError, UnicodeError):
             # Python 3+ TypeError on b'a'.startswith('a') or vice-versa
             continue
 
         # reformat remainder of key to begin with prefix
         rem = key[len(prefix_str):]
         # force repr wrapped in '
         rem_repr = repr(rem + '"')
         if rem_repr.startswith('u') and prefix[0] not in 'uU':
             # Found key is unicode, but prefix is Py2 string.
             # Therefore attempt to interpret key as string.
             try:
                 rem_repr = repr(rem.encode('ascii') + '"')
             except UnicodeEncodeError:
                 continue
 
         rem_repr = rem_repr[1 + rem_repr.index("'"):-2]
         if quote == '"':
             # The entered prefix is quoted with ",
             # but the match is quoted with '.
             # A contained " hence needs escaping for comparison:
             rem_repr = rem_repr.replace('"', '\\"')
 
         # then reinsert prefix from start of token
         matched.append('%s%s' % (token_prefix, rem_repr))
     return quote, token_start, matched
 
 
 def _safe_isinstance(obj, module, class_name):
     """Checks if obj is an instance of module.class_name if loaded
     """
     return (module in sys.modules and
             isinstance(obj, getattr(__import__(module), class_name)))
 
 
 def back_unicode_name_matches(text):
     u"""Match unicode characters back to unicode name
     
     This does  ☃ -> \\snowman
 
     Note that snowman is not a valid python3 combining character but will be expanded.
     Though it will not recombine back to the snowman character by the completion machinery.
 
     This will not either back-complete standard sequences like \\n, \\b ...
     
     Used on Python 3 only.
     """
     if len(text)<2:
         return u'', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return u'', ()
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ['"',"'"]:
         return u'', ()
     try :
         unic = unicodedata.name(char)
         return '\\'+char,['\\'+unic]
     except KeyError:
         pass
     return u'', ()
 
 def back_latex_name_matches(text):
     u"""Match latex characters back to unicode name
     
     This does  ->\\sqrt
 
     Used on Python 3 only.
     """
     if len(text)<2:
         return u'', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return u'', ()
 
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ['"',"'"]:
         return u'', ()
     try :
         latex = reverse_latex_symbol[char]
         # '\\' replace the \ as well
         return '\\'+char,[latex]
     except KeyError:
         pass
     return u'', ()
 
 
 class IPCompleter(Completer):
     """Extension of the completer class with IPython-specific features"""
     
     @observe('greedy')
     def _greedy_changed(self, change):
         """update the splitter and readline delims when greedy is changed"""
         if change['new']:
             self.splitter.delims = GREEDY_DELIMS
         else:
             self.splitter.delims = DELIMS
 
         if self.readline:
             self.readline.set_completer_delims(self.splitter.delims)
     
     merge_completions = Bool(True,
         help="""Whether to merge completion results into a single list
         
         If False, only the completion results from the first non-empty
         completer will be returned.
         """
     ).tag(config=True)
     omit__names = Enum((0,1,2), default_value=2,
         help="""Instruct the completer to omit private method names
         
         Specifically, when completing on ``object.<tab>``.
         
         When 2 [default]: all names that start with '_' will be excluded.
         
         When 1: all 'magic' names (``__foo__``) will be excluded.
         
         When 0: nothing will be excluded.
         """
     ).tag(config=True)
     limit_to__all__ = Bool(False,
         help="""
         DEPRECATED as of version 5.0.
         
         Instruct the completer to use __all__ for the completion
         
         Specifically, when completing on ``object.<tab>``.
         
         When True: only those names in obj.__all__ will be included.
         
         When False [default]: the __all__ attribute is ignored 
         """,
     ).tag(config=True)
 
     def __init__(self, shell=None, namespace=None, global_namespace=None,
                  use_readline=True, config=None, **kwargs):
         """IPCompleter() -> completer
 
         Return a completer object suitable for use by the readline library
         via readline.set_completer().
 
         Inputs:
 
         - shell: a pointer to the ipython shell itself.  This is needed
           because this completer knows about magic functions, and those can
           only be accessed via the ipython instance.
 
         - namespace: an optional dict where completions are performed.
 
         - global_namespace: secondary optional dict for completions, to
           handle cases (such as IPython embedded inside functions) where
           both Python scopes are visible.
 
         use_readline : bool, optional
           If true, use the readline library.  This completer can still function
           without readline, though in that case callers must provide some extra
           information on each call about the current line."""
 
         self.magic_escape = ESC_MAGIC
         self.splitter = CompletionSplitter()
 
         # Readline configuration, only used by the rlcompleter method.
         if use_readline:
             # We store the right version of readline so that later code
             import IPython.utils.rlineimpl as readline
             self.readline = readline
         else:
             self.readline = None
 
         # _greedy_changed() depends on splitter and readline being defined:
         Completer.__init__(self, namespace=namespace, global_namespace=global_namespace,
                             config=config, **kwargs)
 
         # List where completion matches will be stored
         self.matches = []
         self.shell = shell
         # Regexp to split filenames with spaces in them
         self.space_name_re = re.compile(r'([^\\] )')
         # Hold a local ref. to glob.glob for speed
         self.glob = glob.glob
 
         # Determine if we are running on 'dumb' terminals, like (X)Emacs
         # buffers, to avoid completion problems.
         term = os.environ.get('TERM','xterm')
         self.dumb_terminal = term in ['dumb','emacs']
 
         # Special handling of backslashes needed in win32 platforms
         if sys.platform == "win32":
             self.clean_glob = self._clean_glob_win32
         else:
             self.clean_glob = self._clean_glob
 
         #regexp to parse docstring for function signature
         self.docstring_sig_re = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         self.docstring_kwd_re = re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
         #use this if positional argument name is also needed
         #= re.compile(r'[\s|\[]*(\w+)(?:\s*=?\s*.*)')
 
         # All active matcher routines for completion
         self.matchers = [
                          self.python_matches,
                          self.file_matches,
                          self.magic_matches,
                          self.python_func_kw_matches,
                          self.dict_key_matches,
                          ]
 
     def all_completions(self, text):
         """
         Wrapper around the complete method for the benefit of emacs.
         """
         return self.complete(text)[1]
 
     def _clean_glob(self, text):
         return self.glob("%s*" % text)
 
     def _clean_glob_win32(self,text):
         return [f.replace("\\","/")
                 for f in self.glob("%s*" % text)]
 
     def file_matches(self, text):
         """Match filenames, expanding ~USER type strings.
 
         Most of the seemingly convoluted logic in this completer is an
         attempt to handle filenames with spaces in them.  And yet it's not
         quite perfect, because Python's readline doesn't expose all of the
         GNU readline details needed for this to be done correctly.
 
         For a filename with a space in it, the printed completions will be
         only the parts after what's already been typed (instead of the
         full completions, as is normally done).  I don't think with the
         current (as of Python 2.3) Python readline it's possible to do
         better."""
 
         # chars that require escaping with backslash - i.e. chars
         # that readline treats incorrectly as delimiters, but we
         # don't want to treat as delimiters in filename matching
         # when escaped with backslash
         if text.startswith('!'):
             text = text[1:]
             text_prefix = u'!'
         else:
             text_prefix = u''
 
         text_until_cursor = self.text_until_cursor
         # track strings with open quotes
         open_quotes = has_open_quotes(text_until_cursor)
 
         if '(' in text_until_cursor or '[' in text_until_cursor:
             lsplit = text
         else:
             try:
                 # arg_split ~ shlex.split, but with unicode bugs fixed by us
                 lsplit = arg_split(text_until_cursor)[-1]
             except ValueError:
                 # typically an unmatched ", or backslash without escaped char.
                 if open_quotes:
                     lsplit = text_until_cursor.split(open_quotes)[-1]
                 else:
                     return []
             except IndexError:
                 # tab pressed on empty line
                 lsplit = ""
 
         if not open_quotes and lsplit != protect_filename(lsplit):
             # if protectables are found, do matching on the whole escaped name
             has_protectables = True
             text0,text = text,lsplit
         else:
             has_protectables = False
             text = os.path.expanduser(text)
 
         if text == "":
             return [text_prefix + cast_unicode_py2(protect_filename(f)) for f in self.glob("*")]
 
         # Compute the matches from the filesystem
         m0 = self.clean_glob(text.replace('\\',''))
 
         if has_protectables:
             # If we had protectables, we need to revert our changes to the
             # beginning of filename so that we don't double-write the part
             # of the filename we have so far
             len_lsplit = len(lsplit)
             matches = [text_prefix + text0 +
                        protect_filename(f[len_lsplit:]) for f in m0]
         else:
             if open_quotes:
                 # if we have a string with an open quote, we don't need to
                 # protect the names at all (and we _shouldn't_, as it
                 # would cause bugs when the filesystem call is made).
                 matches = m0
             else:
                 matches = [text_prefix +
                            protect_filename(f) for f in m0]
 
         # Mark directories in input list by appending '/' to their names.
         return [cast_unicode_py2(x+'/') if os.path.isdir(x) else x for x in matches]
 
     def magic_matches(self, text):
         """Match magics"""
         # Get all shell magics now rather than statically, so magics loaded at
         # runtime show up too.
         lsm = self.shell.magics_manager.lsmagic()
         line_magics = lsm['line']
         cell_magics = lsm['cell']
         pre = self.magic_escape
         pre2 = pre+pre
         
         # Completion logic:
         # - user gives %%: only do cell magics
         # - user gives %: do both line and cell magics
         # - no prefix: do both
         # In other words, line magics are skipped if the user gives %% explicitly
         bare_text = text.lstrip(pre)
         comp = [ pre2+m for m in cell_magics if m.startswith(bare_text)]
         if not text.startswith(pre2):
             comp += [ pre+m for m in line_magics if m.startswith(bare_text)]
         return [cast_unicode_py2(c) for c in comp]
 
 
     def python_matches(self, text):
         """Match attributes or global python names"""
         if "." in text:
             try:
                 matches = self.attr_matches(text)
                 if text.endswith('.') and self.omit__names:
                     if self.omit__names == 1:
                         # true if txt is _not_ a __ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'.*\.__.*?__',txt) is None)
                     else:
                         # true if txt is _not_ a _ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'\._.*?',txt[txt.rindex('.'):]) is None)
                     matches = filter(no__name, matches)
             except NameError:
                 # catches <undefined attributes>.<tab>
                 matches = []
         else:
             matches = self.global_matches(text)
         return matches
 
     def _default_arguments_from_docstring(self, doc):
         """Parse the first line of docstring for call signature.
 
         Docstring should be of the form 'min(iterable[, key=func])\n'.
         It can also parse cython docstring of the form
         'Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)'.
         """
         if doc is None:
             return []
 
         #care only the firstline
         line = doc.lstrip().splitlines()[0]
 
         #p = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         #'min(iterable[, key=func])\n' -> 'iterable[, key=func]'
         sig = self.docstring_sig_re.search(line)
         if sig is None:
             return []
         # iterable[, key=func]' -> ['iterable[' ,' key=func]']
         sig = sig.groups()[0].split(',')
         ret = []
         for s in sig:
             #re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
             ret += self.docstring_kwd_re.findall(s)
         return ret
 
     def _default_arguments(self, obj):
         """Return the list of default arguments of obj if it is callable,
         or empty list otherwise."""
         call_obj = obj
         ret = []
         if inspect.isbuiltin(obj):
             pass
         elif not (inspect.isfunction(obj) or inspect.ismethod(obj)):
             if inspect.isclass(obj):
                 #for cython embededsignature=True the constructor docstring
                 #belongs to the object itself not __init__
                 ret += self._default_arguments_from_docstring(
                             getattr(obj, '__doc__', ''))
                 # for classes, check for __init__,__new__
                 call_obj = (getattr(obj, '__init__', None) or
                        getattr(obj, '__new__', None))
             # for all others, check if they are __call__able
             elif hasattr(obj, '__call__'):
                 call_obj = obj.__call__
         ret += self._default_arguments_from_docstring(
                  getattr(call_obj, '__doc__', ''))
 
         if PY3:
             _keeps = (inspect.Parameter.KEYWORD_ONLY,
                       inspect.Parameter.POSITIONAL_OR_KEYWORD)
             signature = inspect.signature
         else:
             import IPython.utils.signatures
             _keeps = (IPython.utils.signatures.Parameter.KEYWORD_ONLY,
                       IPython.utils.signatures.Parameter.POSITIONAL_OR_KEYWORD)
             signature = IPython.utils.signatures.signature
 
         try:
             sig = signature(call_obj)
             ret.extend(k for k, v in sig.parameters.items() if
                        v.kind in _keeps)
         except ValueError:
             pass
 
         return list(set(ret))
 
     def python_func_kw_matches(self,text):
         """Match named parameters (kwargs) of the last open function"""
 
         if "." in text: # a parameter cannot be dotted
             return []
         try: regexp = self.__funcParamsRegex
         except AttributeError:
             regexp = self.__funcParamsRegex = re.compile(r'''
                 '.*?(?<!\\)' |    # single quoted strings or
                 ".*?(?<!\\)" |    # double quoted strings or
                 \w+          |    # identifier
                 \S                # other characters
                 ''', re.VERBOSE | re.DOTALL)
         # 1. find the nearest identifier that comes before an unclosed
         # parenthesis before the cursor
         # e.g. for "foo (1+bar(x), pa<cursor>,a=1)", the candidate is "foo"
         tokens = regexp.findall(self.text_until_cursor)
         tokens.reverse()
         iterTokens = iter(tokens); openPar = 0
 
         for token in iterTokens:
             if token == ')':
                 openPar -= 1
             elif token == '(':
                 openPar += 1
                 if openPar > 0:
                     # found the last unclosed parenthesis
                     break
         else:
             return []
         # 2. Concatenate dotted names ("foo.bar" for "foo.bar(x, pa" )
         ids = []
         isId = re.compile(r'\w+$').match
 
         while True:
             try:
                 ids.append(next(iterTokens))
                 if not isId(ids[-1]):
                     ids.pop(); break
                 if not next(iterTokens) == '.':
                     break
             except StopIteration:
                 break
         # lookup the candidate callable matches either using global_matches
         # or attr_matches for dotted names
         if len(ids) == 1:
             callableMatches = self.global_matches(ids[0])
         else:
             callableMatches = self.attr_matches('.'.join(ids[::-1]))
         argMatches = []
         for callableMatch in callableMatches:
             try:
                 namedArgs = self._default_arguments(eval(callableMatch,
                                                         self.namespace))
             except:
                 continue
 
             for namedArg in namedArgs:
                 if namedArg.startswith(text):
                     argMatches.append(u"%s=" %namedArg)
         return argMatches
 
     def dict_key_matches(self, text):
         "Match string keys in a dictionary, after e.g. 'foo[' "
         def get_keys(obj):
             # Objects can define their own completions by defining an
             # _ipy_key_completions_() method.
             method = get_real_method(obj, '_ipython_key_completions_')
             if method is not None:
                 return method()
 
             # Special case some common in-memory dict-like types
             if isinstance(obj, dict) or\
                _safe_isinstance(obj, 'pandas', 'DataFrame'):
                 try:
                     return list(obj.keys())
                 except Exception:
                     return []
             elif _safe_isinstance(obj, 'numpy', 'ndarray') or\
                  _safe_isinstance(obj, 'numpy', 'void'):
                 return obj.dtype.names or []
             return []
 
         try:
             regexps = self.__dict_key_regexps
         except AttributeError:
             dict_key_re_fmt = r'''(?x)
             (  # match dict-referring expression wrt greedy setting
                 %s
             )
             \[   # open bracket
             \s*  # and optional whitespace
             ([uUbB]?  # string prefix (r not handled)
                 (?:   # unclosed string
                     '(?:[^']|(?<!\\)\\')*
                 |
                     "(?:[^"]|(?<!\\)\\")*
                 )
             )?
             $
             '''
             regexps = self.__dict_key_regexps = {
                 False: re.compile(dict_key_re_fmt % '''
                                   # identifiers separated by .
                                   (?!\d)\w+
                                   (?:\.(?!\d)\w+)*
                                   '''),
                 True: re.compile(dict_key_re_fmt % '''
                                  .+
                                  ''')
             }
 
         match = regexps[self.greedy].search(self.text_until_cursor)
         if match is None:
             return []
 
         expr, prefix = match.groups()
         try:
             obj = eval(expr, self.namespace)
         except Exception:
             try:
                 obj = eval(expr, self.global_namespace)
             except Exception:
                 return []
 
         keys = get_keys(obj)
         if not keys:
             return keys
         closing_quote, token_offset, matches = match_dict_keys(keys, prefix, self.splitter.delims)
         if not matches:
             return matches
         
         # get the cursor position of
         # - the text being completed
         # - the start of the key text
         # - the start of the completion
         text_start = len(self.text_until_cursor) - len(text)
         if prefix:
             key_start = match.start(2)
             completion_start = key_start + token_offset
         else:
             key_start = completion_start = match.end()
         
         # grab the leading prefix, to make sure all completions start with `text`
         if text_start > key_start:
             leading = ''
         else:
             leading = text[text_start:completion_start]
         
         # the index of the `[` character
         bracket_idx = match.end(1)
 
         # append closing quote and bracket as appropriate
         # this is *not* appropriate if the opening quote or bracket is outside
         # the text given to this method
         suf = ''
         continuation = self.line_buffer[len(self.text_until_cursor):]
         if key_start > text_start and closing_quote:
             # quotes were opened inside text, maybe close them
             if continuation.startswith(closing_quote):
                 continuation = continuation[len(closing_quote):]
             else:
                 suf += closing_quote
         if bracket_idx > text_start:
             # brackets were opened inside text, maybe close them
             if not continuation.startswith(']'):
                 suf += ']'
         
         return [leading + k + suf for k in matches]
 
     def unicode_name_matches(self, text):
         u"""Match Latex-like syntax for unicode characters base 
         on the name of the character.
         
         This does  \\GREEK SMALL LETTER ETA -> η
 
         Works only on valid python 3 identifier, or on combining characters that 
         will combine to form a valid identifier.
         
         Used on Python 3 only.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos+1:]
             try :
                 unic = unicodedata.lookup(s)
                 # allow combining chars
                 if ('a'+unic).isidentifier():
                     return '\\'+s,[unic]
             except KeyError:
                 pass
         return u'', []
 
 
 
 
     def latex_matches(self, text):
         u"""Match Latex syntax for unicode characters.
         
         This does both \\alp -> \\alpha and \\alpha -> α
         
         Used on Python 3 only.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos:]
             if s in latex_symbols:
                 # Try to complete a full latex symbol to unicode
                 # \\alpha -> α
                 return s, [latex_symbols[s]]
             else:
                 # If a user has partially typed a latex symbol, give them
                 # a full list of options \al -> [\aleph, \alpha]
                 matches = [k for k in latex_symbols if k.startswith(s)]
                 return s, matches
         return u'', []
 
     def dispatch_custom_completer(self, text):
         line = self.line_buffer
         if not line.strip():
             return None
 
         # Create a little structure to pass all the relevant information about
         # the current completion to any custom completer.
         event = Bunch()
         event.line = line
         event.symbol = text
         cmd = line.split(None,1)[0]
         event.command = cmd
         event.text_until_cursor = self.text_until_cursor
 
         # for foo etc, try also to find completer for %foo
         if not cmd.startswith(self.magic_escape):
             try_magic = self.custom_completers.s_matches(
                 self.magic_escape + cmd)
         else:
             try_magic = []
 
         for c in itertools.chain(self.custom_completers.s_matches(cmd),
                  try_magic,
                  self.custom_completers.flat_matches(self.text_until_cursor)):
             try:
                 res = c(event)
                 if res:
                     # first, try case sensitive match
                     withcase = [cast_unicode_py2(r) for r in res if r.startswith(text)]
                     if withcase:
                         return withcase
                     # if none, then case insensitive ones are ok too
                     text_low = text.lower()
                     return [cast_unicode_py2(r) for r in res if r.lower().startswith(text_low)]
             except TryNext:
                 pass
 
         return None
 
     def complete(self, text=None, line_buffer=None, cursor_pos=None):
         """Find completions for the given text and line context.
 
         Note that both the text and the line_buffer are optional, but at least
         one of them must be given.
 
         Parameters
         ----------
           text : string, optional
             Text to perform the completion on.  If not given, the line buffer
             is split using the instance's CompletionSplitter object.
 
           line_buffer : string, optional
             If not given, the completer attempts to obtain the current line
             buffer via readline.  This keyword allows clients which are
             requesting for text completions in non-readline contexts to inform
             the completer of the entire text.
 
           cursor_pos : int, optional
             Index of the cursor in the full line buffer.  Should be provided by
             remote frontends where kernel has no access to frontend state.
 
         Returns
         -------
         text : str
           Text that was actually used in the completion.
 
         matches : list
           A list of completion matches.
         """
         # if the cursor position isn't given, the only sane assumption we can
         # make is that it's at the end of the line (the common case)
         if cursor_pos is None:
             cursor_pos = len(line_buffer) if text is None else len(text)
 
         if PY3:
 
             base_text = text if not line_buffer else line_buffer[:cursor_pos]
             latex_text, latex_matches = self.latex_matches(base_text)
             if latex_matches:
                  return latex_text, latex_matches
             name_text = ''
             name_matches = []
             for meth in (self.unicode_name_matches, back_latex_name_matches, back_unicode_name_matches):
                 name_text, name_matches = meth(base_text)
                 if name_text:
                     return name_text, name_matches
         
         # if text is either None or an empty string, rely on the line buffer
         if not text:
             text = self.splitter.split_line(line_buffer, cursor_pos)
 
         # If no line buffer is given, assume the input text is all there was
         if line_buffer is None:
             line_buffer = text
 
         self.line_buffer = line_buffer
         self.text_until_cursor = self.line_buffer[:cursor_pos]
 
         # Start with a clean slate of completions
         self.matches[:] = []
         custom_res = self.dispatch_custom_completer(text)
         if custom_res is not None:
             # did custom completers produce something?
             self.matches = custom_res
         else:
             # Extend the list of completions with the results of each
             # matcher, so we return results to the user from all
             # namespaces.
             if self.merge_completions:
                 self.matches = []
                 for matcher in self.matchers:
                     try:
                         self.matches.extend(matcher(text))
                     except:
                         # Show the ugly traceback if the matcher causes an
                         # exception, but do NOT crash the kernel!
                         sys.excepthook(*sys.exc_info())
             else:
                 for matcher in self.matchers:
                     self.matches = matcher(text)
                     if self.matches:
                         break
         # FIXME: we should extend our api to return a dict with completions for
         # different types of objects.  The rlcomplete() method could then
         # simply collapse the dict into a list for readline, but we'd have
         # richer completion semantics in other evironments.
         self.matches = sorted(set(self.matches), key=completions_sorting_key)
 
         return text, self.matches
 
     def rlcomplete(self, text, state):
         """Return the state-th possible completion for 'text'.
 
         This is called successively with state == 0, 1, 2, ... until it
         returns None.  The completion should begin with 'text'.
 
         Parameters
         ----------
           text : string
             Text to perform the completion on.
 
           state : int
             Counter used by readline.
         """
         if state==0:
 
             self.line_buffer = line_buffer = self.readline.get_line_buffer()
             cursor_pos = self.readline.get_endidx()
 
             #io.rprint("\nRLCOMPLETE: %r %r %r" %
             #          (text, line_buffer, cursor_pos) ) # dbg
 
             # if there is only a tab on a line with only whitespace, instead of
             # the mostly useless 'do you want to see all million completions'
             # message, just do the right thing and give the user his tab!
             # Incidentally, this enables pasting of tabbed text from an editor
             # (as long as autoindent is off).
 
             # It should be noted that at least pyreadline still shows file
             # completions - is there a way around it?
 
             # don't apply this on 'dumb' terminals, such as emacs buffers, so
             # we don't interfere with their own tab-completion mechanism.
             if not (self.dumb_terminal or line_buffer.strip()):
                 self.readline.insert_text('\t')
                 sys.stdout.flush()
                 return None
 
             # Note: debugging exceptions that may occur in completion is very
             # tricky, because readline unconditionally silences them.  So if
             # during development you suspect a bug in the completion code, turn
             # this flag on temporarily by uncommenting the second form (don't
             # flip the value in the first line, as the '# dbg' marker can be
             # automatically detected and is used elsewhere).
             DEBUG = False
             #DEBUG = True # dbg
             if DEBUG:
                 try:
                     self.complete(text, line_buffer, cursor_pos)
                 except:
                     import traceback; traceback.print_exc()
             else:
                 # The normal production version is here
 
                 # This method computes the self.matches array
                 self.complete(text, line_buffer, cursor_pos)
 
         try:
             return self.matches[state]
         except IndexError:
             return None
 

IPython/utils/path.py

@@ -1,449 +1,452 b''
 # encoding: utf-8
 """
 Utilities for path handling.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import os
 import sys
 import errno
 import shutil
 import random
 import tempfile
 import glob
 from warnings import warn
 from hashlib import md5
 
 from IPython.utils.process import system
 from IPython.utils import py3compat
 from IPython.utils.decorators import undoc
 
 #-----------------------------------------------------------------------------
 # Code
 #-----------------------------------------------------------------------------
 
 fs_encoding = sys.getfilesystemencoding()
 
 def _writable_dir(path):
     """Whether `path` is a directory, to which the user has write access."""
     return os.path.isdir(path) and os.access(path, os.W_OK)
 
 if sys.platform == 'win32':
     def _get_long_path_name(path):
         """Get a long path name (expand ~) on Windows using ctypes.
 
         Examples
         --------
 
         >>> get_long_path_name('c:\\docume~1')
         u'c:\\\\Documents and Settings'
 
         """
         try:
             import ctypes
         except ImportError:
             raise ImportError('you need to have ctypes installed for this to work')
         _GetLongPathName = ctypes.windll.kernel32.GetLongPathNameW
         _GetLongPathName.argtypes = [ctypes.c_wchar_p, ctypes.c_wchar_p,
             ctypes.c_uint ]
 
         buf = ctypes.create_unicode_buffer(260)
         rv = _GetLongPathName(path, buf, 260)
         if rv == 0 or rv > 260:
             return path
         else:
             return buf.value
 else:
     def _get_long_path_name(path):
         """Dummy no-op."""
         return path
 
 
 
 def get_long_path_name(path):
     """Expand a path into its long form.
 
     On Windows this expands any ~ in the paths. On other platforms, it is
     a null operation.
     """
     return _get_long_path_name(path)
 
 
 def unquote_filename(name, win32=(sys.platform=='win32')):
     """ On Windows, remove leading and trailing quotes from filenames.
+
+    This function has been deprecated and should not be used any more:
+    unquoting is now taken care of by :func:`IPython.utils.process.arg_split`.
     """
     warn("'unquote_filename' is deprecated", DeprecationWarning)
     if win32:
         if name.startswith(("'", '"')) and name.endswith(("'", '"')):
             name = name[1:-1]
     return name
 
 
 def compress_user(path):
     """Reverse of :func:`os.path.expanduser`
-    """    
+    """
     path = py3compat.unicode_to_str(path, sys.getfilesystemencoding())
     home = os.path.expanduser('~')
     if path.startswith(home):
         path =  "~" + path[len(home):]
     return path
 
 def get_py_filename(name, force_win32=None):
     """Return a valid python filename in the current directory.
 
     If the given name is not a file, it adds '.py' and searches again.
     Raises IOError with an informative message if the file isn't found.
 
     On Windows, apply Windows semantics to the filename. In particular, remove
     any quoting that has been applied to it. This option can be forced for
     testing purposes.
     """
 
     name = os.path.expanduser(name)
     if force_win32 is None:
         win32 = (sys.platform == 'win32')
     else:
         win32 = force_win32
     name = unquote_filename(name, win32=win32)
     if not os.path.isfile(name) and not name.endswith('.py'):
         name += '.py'
     if os.path.isfile(name):
         return name
     else:
         raise IOError('File `%r` not found.' % name)
 
 
 def filefind(filename, path_dirs=None):
     """Find a file by looking through a sequence of paths.
 
     This iterates through a sequence of paths looking for a file and returns
     the full, absolute path of the first occurence of the file.  If no set of
     path dirs is given, the filename is tested as is, after running through
     :func:`expandvars` and :func:`expanduser`.  Thus a simple call::
 
         filefind('myfile.txt')
 
     will find the file in the current working dir, but::
 
         filefind('~/myfile.txt')
 
     Will find the file in the users home directory.  This function does not
     automatically try any paths, such as the cwd or the user's home directory.
 
     Parameters
     ----------
     filename : str
         The filename to look for.
     path_dirs : str, None or sequence of str
         The sequence of paths to look for the file in.  If None, the filename
         need to be absolute or be in the cwd.  If a string, the string is
         put into a sequence and the searched.  If a sequence, walk through
         each element and join with ``filename``, calling :func:`expandvars`
         and :func:`expanduser` before testing for existence.
 
     Returns
     -------
     Raises :exc:`IOError` or returns absolute path to file.
     """
 
     # If paths are quoted, abspath gets confused, strip them...
     filename = filename.strip('"').strip("'")
     # If the input is an absolute path, just check it exists
     if os.path.isabs(filename) and os.path.isfile(filename):
         return filename
 
     if path_dirs is None:
         path_dirs = ("",)
     elif isinstance(path_dirs, py3compat.string_types):
         path_dirs = (path_dirs,)
 
     for path in path_dirs:
         if path == '.': path = py3compat.getcwd()
         testname = expand_path(os.path.join(path, filename))
         if os.path.isfile(testname):
             return os.path.abspath(testname)
 
     raise IOError("File %r does not exist in any of the search paths: %r" %
                   (filename, path_dirs) )
 
 
 class HomeDirError(Exception):
     pass
 
 
 def get_home_dir(require_writable=False):
     """Return the 'home' directory, as a unicode string.
 
     Uses os.path.expanduser('~'), and checks for writability.
 
     See stdlib docs for how this is determined.
     $HOME is first priority on *ALL* platforms.
 
     Parameters
     ----------
 
     require_writable : bool [default: False]
         if True:
             guarantees the return value is a writable directory, otherwise
             raises HomeDirError
         if False:
             The path is resolved, but it is not guaranteed to exist or be writable.
     """
 
     homedir = os.path.expanduser('~')
     # Next line will make things work even when /home/ is a symlink to
     # /usr/home as it is on FreeBSD, for example
     homedir = os.path.realpath(homedir)
 
     if not _writable_dir(homedir) and os.name == 'nt':
         # expanduser failed, use the registry to get the 'My Documents' folder.
         try:
             try:
                 import winreg as wreg  # Py 3
             except ImportError:
                 import _winreg as wreg  # Py 2
             key = wreg.OpenKey(
                 wreg.HKEY_CURRENT_USER,
                 "Software\Microsoft\Windows\CurrentVersion\Explorer\Shell Folders"
             )
             homedir = wreg.QueryValueEx(key,'Personal')[0]
             key.Close()
         except:
             pass
 
     if (not require_writable) or _writable_dir(homedir):
         return py3compat.cast_unicode(homedir, fs_encoding)
     else:
         raise HomeDirError('%s is not a writable dir, '
                 'set $HOME environment variable to override' % homedir)
 
 def get_xdg_dir():
     """Return the XDG_CONFIG_HOME, if it is defined and exists, else None.
 
     This is only for non-OS X posix (Linux,Unix,etc.) systems.
     """
 
     env = os.environ
 
     if os.name == 'posix' and sys.platform != 'darwin':
         # Linux, Unix, AIX, etc.
         # use ~/.config if empty OR not set
         xdg = env.get("XDG_CONFIG_HOME", None) or os.path.join(get_home_dir(), '.config')
         if xdg and _writable_dir(xdg):
             return py3compat.cast_unicode(xdg, fs_encoding)
 
     return None
 
 
 def get_xdg_cache_dir():
     """Return the XDG_CACHE_HOME, if it is defined and exists, else None.
 
     This is only for non-OS X posix (Linux,Unix,etc.) systems.
     """
 
     env = os.environ
 
     if os.name == 'posix' and sys.platform != 'darwin':
         # Linux, Unix, AIX, etc.
         # use ~/.cache if empty OR not set
         xdg = env.get("XDG_CACHE_HOME", None) or os.path.join(get_home_dir(), '.cache')
         if xdg and _writable_dir(xdg):
             return py3compat.cast_unicode(xdg, fs_encoding)
 
     return None
 
 
 @undoc
 def get_ipython_dir():
     warn("get_ipython_dir has moved to the IPython.paths module")
     from IPython.paths import get_ipython_dir
     return get_ipython_dir()
 
 @undoc
 def get_ipython_cache_dir():
     warn("get_ipython_cache_dir has moved to the IPython.paths module")
     from IPython.paths import get_ipython_cache_dir
     return get_ipython_cache_dir()
 
 @undoc
 def get_ipython_package_dir():
     warn("get_ipython_package_dir has moved to the IPython.paths module")
     from IPython.paths import get_ipython_package_dir
     return get_ipython_package_dir()
 
 @undoc
 def get_ipython_module_path(module_str):
     warn("get_ipython_module_path has moved to the IPython.paths module")
     from IPython.paths import get_ipython_module_path
     return get_ipython_module_path(module_str)
 
 @undoc
 def locate_profile(profile='default'):
     warn("locate_profile has moved to the IPython.paths module")
     from IPython.paths import locate_profile
     return locate_profile(profile=profile)
 
 def expand_path(s):
     """Expand $VARS and ~names in a string, like a shell
 
     :Examples:
 
        In [2]: os.environ['FOO']='test'
 
        In [3]: expand_path('variable FOO is $FOO')
        Out[3]: 'variable FOO is test'
     """
     # This is a pretty subtle hack. When expand user is given a UNC path
     # on Windows (\\server\share$\%username%), os.path.expandvars, removes
     # the $ to get (\\server\share\%username%). I think it considered $
     # alone an empty var. But, we need the $ to remains there (it indicates
     # a hidden share).
     if os.name=='nt':
         s = s.replace('$\\', 'IPYTHON_TEMP')
     s = os.path.expandvars(os.path.expanduser(s))
     if os.name=='nt':
         s = s.replace('IPYTHON_TEMP', '$\\')
     return s
 
 
 def unescape_glob(string):
     """Unescape glob pattern in `string`."""
     def unescape(s):
         for pattern in '*[]!?':
             s = s.replace(r'\{0}'.format(pattern), pattern)
         return s
     return '\\'.join(map(unescape, string.split('\\\\')))
 
 
 def shellglob(args):
     """
     Do glob expansion for each element in `args` and return a flattened list.
 
     Unmatched glob pattern will remain as-is in the returned list.
 
     """
     expanded = []
     # Do not unescape backslash in Windows as it is interpreted as
     # path separator:
     unescape = unescape_glob if sys.platform != 'win32' else lambda x: x
     for a in args:
         expanded.extend(glob.glob(a) or [unescape(a)])
     return expanded
 
 
 def target_outdated(target,deps):
     """Determine whether a target is out of date.
 
     target_outdated(target,deps) -> 1/0
 
     deps: list of filenames which MUST exist.
     target: single filename which may or may not exist.
 
     If target doesn't exist or is older than any file listed in deps, return
     true, otherwise return false.
     """
     try:
         target_time = os.path.getmtime(target)
     except os.error:
         return 1
     for dep in deps:
         dep_time = os.path.getmtime(dep)
         if dep_time > target_time:
             #print "For target",target,"Dep failed:",dep # dbg
             #print "times (dep,tar):",dep_time,target_time # dbg
             return 1
     return 0
 
 
 def target_update(target,deps,cmd):
     """Update a target with a given command given a list of dependencies.
 
     target_update(target,deps,cmd) -> runs cmd if target is outdated.
 
     This is just a wrapper around target_outdated() which calls the given
     command if target is outdated."""
 
     if target_outdated(target,deps):
         system(cmd)
 
 @undoc
 def filehash(path):
     """Make an MD5 hash of a file, ignoring any differences in line
     ending characters."""
     warn("filehash() is deprecated")
     with open(path, "rU") as f:
         return md5(py3compat.str_to_bytes(f.read())).hexdigest()
 
 ENOLINK = 1998
 
 def link(src, dst):
     """Hard links ``src`` to ``dst``, returning 0 or errno.
 
     Note that the special errno ``ENOLINK`` will be returned if ``os.link`` isn't
     supported by the operating system.
     """
 
     if not hasattr(os, "link"):
         return ENOLINK
     link_errno = 0
     try:
         os.link(src, dst)
     except OSError as e:
         link_errno = e.errno
     return link_errno
 
 
 def link_or_copy(src, dst):
     """Attempts to hardlink ``src`` to ``dst``, copying if the link fails.
 
     Attempts to maintain the semantics of ``shutil.copy``.
 
     Because ``os.link`` does not overwrite files, a unique temporary file
     will be used if the target already exists, then that file will be moved
     into place.
     """
 
     if os.path.isdir(dst):
         dst = os.path.join(dst, os.path.basename(src))
 
     link_errno = link(src, dst)
     if link_errno == errno.EEXIST:
         if os.stat(src).st_ino == os.stat(dst).st_ino:
             # dst is already a hard link to the correct file, so we don't need
             # to do anything else. If we try to link and rename the file
             # anyway, we get duplicate files - see http://bugs.python.org/issue21876
             return
 
         new_dst = dst + "-temp-%04X" %(random.randint(1, 16**4), )
         try:
             link_or_copy(src, new_dst)
         except:
             try:
                 os.remove(new_dst)
             except OSError:
                 pass
             raise
         os.rename(new_dst, dst)
     elif link_errno != 0:
         # Either link isn't supported, or the filesystem doesn't support
         # linking, or 'src' and 'dst' are on different filesystems.
         shutil.copy(src, dst)
 
 def ensure_dir_exists(path, mode=0o755):
     """ensure that a directory exists
 
     If it doesn't exist, try to create it and protect against a race condition
     if another process is doing the same.
 
     The default permissions are 755, which differ from os.makedirs default of 777.
     """
     if not os.path.exists(path):
         try:
             os.makedirs(path, mode=mode)
         except OSError as e:
             if e.errno != errno.EEXIST:
                 raise
     elif not os.path.isdir(path):
         raise IOError("%r exists but is not a directory" % path)