cola/utils.py

   1 # Copyright (c) 2008 David Aguilar
   2 """This module provides miscellaneous utility functions."""
   3 from __future__ import division, absolute_import, unicode_literals
   4 import os
   5 import random
   6 import re
   7 import shlex
   8 import sys
   9 import tempfile
  10 import time
  11 import traceback
  12
  13 from . import core
  14
  15 random.seed(hash(time.time()))
  16
  17
  18 def add_parents(paths):
  19     """Iterate over each item in the set and add its parent directories."""
  20     all_paths = set()
  21     for path in paths:
  22         while '//' in path:
  23             path = path.replace('//', '/')
  24         all_paths.add(path)
  25         if '/' in path:
  26             parent_dir = dirname(path)
  27             while parent_dir:
  28                 all_paths.add(parent_dir)
  29                 parent_dir = dirname(parent_dir)
  30     return all_paths
  31
  32
  33 def format_exception(e):
  34     exc_type, exc_value, exc_tb = sys.exc_info()
  35     details = traceback.format_exception(exc_type, exc_value, exc_tb)
  36     details = '\n'.join(map(core.decode, details))
  37     if hasattr(e, 'msg'):
  38         msg = e.msg
  39     else:
  40         msg = core.decode(repr(e))
  41     return (msg, details)
  42
  43
  44 def sublist(a, b):
  45     """Subtracts list b from list a and returns the resulting list."""
  46     # conceptually, c = a - b
  47     c = []
  48     for item in a:
  49         if item not in b:
  50             c.append(item)
  51     return c
  52
  53
  54 __grep_cache = {}
  55
  56
  57 def grep(pattern, items, squash=True):
  58     """Greps a list for items that match a pattern
  59
  60     :param squash: If only one item matches, return just that item
  61     :returns: List of matching items
  62
  63     """
  64     isdict = type(items) is dict
  65     if pattern in __grep_cache:
  66         regex = __grep_cache[pattern]
  67     else:
  68         regex = __grep_cache[pattern] = re.compile(pattern)
  69     matched = []
  70     matchdict = {}
  71     for item in items:
  72         match = regex.match(item)
  73         if not match:
  74             continue
  75         groups = match.groups()
  76         if not groups:
  77             subitems = match.group(0)
  78         else:
  79             if len(groups) == 1:
  80                 subitems = groups[0]
  81             else:
  82                 subitems = list(groups)
  83         if isdict:
  84             matchdict[item] = items[item]
  85         else:
  86             matched.append(subitems)
  87
  88     if isdict:
  89         return matchdict
  90     else:
  91         if squash and len(matched) == 1:
  92             return matched[0]
  93         else:
  94             return matched
  95
  96
  97 def basename(path):
  98     """
  99     An os.path.basename() implementation that always uses '/'
 100
 101     Avoid os.path.basename because git's output always
 102     uses '/' regardless of platform.
 103
 104     """
 105     return path.rsplit('/', 1)[-1]
 106
 107
 108 def strip_one(path):
 109     """Strip one level of directory"""
 110     return path.strip('/').split('/', 1)[-1]
 111
 112
 113 def dirname(path, current_dir=''):
 114     """
 115     An os.path.dirname() implementation that always uses '/'
 116
 117     Avoid os.path.dirname because git's output always
 118     uses '/' regardless of platform.
 119
 120     """
 121     while '//' in path:
 122         path = path.replace('//', '/')
 123     path_dirname = path.rsplit('/', 1)[0]
 124     if path_dirname == path:
 125         return current_dir
 126     return path.rsplit('/', 1)[0]
 127
 128
 129 def select_directory(paths):
 130     """Return the first directory in a list of paths"""
 131     if not paths:
 132         return core.getcwd()
 133
 134     for path in paths:
 135         if core.isdir(path):
 136             return path
 137
 138     return os.path.dirname(paths[0])
 139
 140
 141 def strip_prefix(prefix, string):
 142     """Return string, without the prefix. Blow up if string doesn't
 143     start with prefix."""
 144     assert string.startswith(prefix)
 145     return string[len(prefix):]
 146
 147
 148 def sanitize(s):
 149     """Removes shell metacharacters from a string."""
 150     for c in """ \t!@#$%^&*()\\;,<>"'[]{}~|""":
 151         s = s.replace(c, '_')
 152     return s
 153
 154
 155 def tablength(word, tabwidth):
 156     """Return length of a word taking tabs into account
 157
 158     >>> tablength("\\t\\t\\t\\tX", 8)
 159     33
 160
 161     """
 162     return len(word.replace('\t', '')) + word.count('\t') * tabwidth
 163
 164
 165 def _shell_split(s):
 166     """Split string apart into utf-8 encoded words using shell syntax"""
 167     try:
 168         return shlex.split(core.encode(s))
 169     except ValueError:
 170         return [core.encode(s)]
 171
 172
 173 if sys.version_info[0] == 3:
 174     # In Python 3, we don't need the encode/decode dance
 175     shell_split = shlex.split
 176 else:
 177     def shell_split(s):
 178         """Returns a unicode list instead of encoded strings"""
 179         return [core.decode(arg) for arg in _shell_split(s)]
 180
 181
 182 def tmp_filename(label):
 183     label = 'git-cola-' + label.replace('/', '-').replace('\\', '-')
 184     fd = tempfile.NamedTemporaryFile(prefix=label+'-')
 185     fd.close()
 186     return fd.name
 187
 188
 189 def is_linux():
 190     """Is this a linux machine?"""
 191     return sys.platform.startswith('linux')
 192
 193
 194 def is_debian():
 195     """Is it debian?"""
 196     return os.path.exists('/usr/bin/apt-get')
 197
 198
 199 def is_darwin():
 200     """Return True on OSX."""
 201     return sys.platform == 'darwin'
 202
 203
 204 def is_win32():
 205     """Return True on win32"""
 206     return sys.platform == 'win32' or sys.platform == 'cygwin'
 207
 208
 209 def expandpath(path):
 210     """Expand ~user/ and environment $variables"""
 211     path = os.path.expandvars(path)
 212     if path.startswith('~'):
 213         path = os.path.expanduser(path)
 214     return path
 215
 216
 217 class Group(object):
 218     """Operate on a collection of objects as a single unit"""
 219
 220     def __init__(self, *members):
 221         self._members = members
 222
 223     def __getattr__(self, name):
 224         """Return a function that relays calls to the group"""
 225         def relay(*args, **kwargs):
 226             for member in self._members:
 227                 method = getattr(member, name)
 228                 method(*args, **kwargs)
 229         setattr(self, name, relay)
 230         return relay
 231
 232
 233 class Proxy(object):
 234     """Wrap an object and override attributes"""
 235
 236     def __init__(self, obj, **overrides):
 237         self._obj = obj
 238         for k, v in overrides.items():
 239             setattr(self, k, v)
 240
 241     def __getattr__(self, name):
 242         return getattr(self._obj, name)