Spaces:
Running
Running
File size: 8,223 Bytes
b72ab63 |
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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 |
"""
This module implements the algorithm for converting between a "user name" -
something that a user can choose arbitrarily inside a font editor - and a file
name suitable for use in a wide range of operating systems and filesystems.
The `UFO 3 specification <http://unifiedfontobject.org/versions/ufo3/conventions/>`_
provides an example of an algorithm for such conversion, which avoids illegal
characters, reserved file names, ambiguity between upper- and lower-case
characters, and clashes with existing files.
This code was originally copied from
`ufoLib <https://github.com/unified-font-object/ufoLib/blob/8747da7/Lib/ufoLib/filenames.py>`_
by Tal Leming and is copyright (c) 2005-2016, The RoboFab Developers:
- Erik van Blokland
- Tal Leming
- Just van Rossum
"""
illegalCharacters = r"\" * + / : < > ? [ \ ] | \0".split(" ")
illegalCharacters += [chr(i) for i in range(1, 32)]
illegalCharacters += [chr(0x7F)]
reservedFileNames = "CON PRN AUX CLOCK$ NUL A:-Z: COM1".lower().split(" ")
reservedFileNames += "LPT1 LPT2 LPT3 COM2 COM3 COM4".lower().split(" ")
maxFileNameLength = 255
class NameTranslationError(Exception):
pass
def userNameToFileName(userName, existing=[], prefix="", suffix=""):
"""Converts from a user name to a file name.
Takes care to avoid illegal characters, reserved file names, ambiguity between
upper- and lower-case characters, and clashes with existing files.
Args:
userName (str): The input file name.
existing: A case-insensitive list of all existing file names.
prefix: Prefix to be prepended to the file name.
suffix: Suffix to be appended to the file name.
Returns:
A suitable filename.
Raises:
NameTranslationError: If no suitable name could be generated.
Examples::
>>> userNameToFileName("a") == "a"
True
>>> userNameToFileName("A") == "A_"
True
>>> userNameToFileName("AE") == "A_E_"
True
>>> userNameToFileName("Ae") == "A_e"
True
>>> userNameToFileName("ae") == "ae"
True
>>> userNameToFileName("aE") == "aE_"
True
>>> userNameToFileName("a.alt") == "a.alt"
True
>>> userNameToFileName("A.alt") == "A_.alt"
True
>>> userNameToFileName("A.Alt") == "A_.A_lt"
True
>>> userNameToFileName("A.aLt") == "A_.aL_t"
True
>>> userNameToFileName(u"A.alT") == "A_.alT_"
True
>>> userNameToFileName("T_H") == "T__H_"
True
>>> userNameToFileName("T_h") == "T__h"
True
>>> userNameToFileName("t_h") == "t_h"
True
>>> userNameToFileName("F_F_I") == "F__F__I_"
True
>>> userNameToFileName("f_f_i") == "f_f_i"
True
>>> userNameToFileName("Aacute_V.swash") == "A_acute_V_.swash"
True
>>> userNameToFileName(".notdef") == "_notdef"
True
>>> userNameToFileName("con") == "_con"
True
>>> userNameToFileName("CON") == "C_O_N_"
True
>>> userNameToFileName("con.alt") == "_con.alt"
True
>>> userNameToFileName("alt.con") == "alt._con"
True
"""
# the incoming name must be a str
if not isinstance(userName, str):
raise ValueError("The value for userName must be a string.")
# establish the prefix and suffix lengths
prefixLength = len(prefix)
suffixLength = len(suffix)
# replace an initial period with an _
# if no prefix is to be added
if not prefix and userName[0] == ".":
userName = "_" + userName[1:]
# filter the user name
filteredUserName = []
for character in userName:
# replace illegal characters with _
if character in illegalCharacters:
character = "_"
# add _ to all non-lower characters
elif character != character.lower():
character += "_"
filteredUserName.append(character)
userName = "".join(filteredUserName)
# clip to 255
sliceLength = maxFileNameLength - prefixLength - suffixLength
userName = userName[:sliceLength]
# test for illegal files names
parts = []
for part in userName.split("."):
if part.lower() in reservedFileNames:
part = "_" + part
parts.append(part)
userName = ".".join(parts)
# test for clash
fullName = prefix + userName + suffix
if fullName.lower() in existing:
fullName = handleClash1(userName, existing, prefix, suffix)
# finished
return fullName
def handleClash1(userName, existing=[], prefix="", suffix=""):
"""
existing should be a case-insensitive list
of all existing file names.
>>> prefix = ("0" * 5) + "."
>>> suffix = "." + ("0" * 10)
>>> existing = ["a" * 5]
>>> e = list(existing)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000001.0000000000')
True
>>> e = list(existing)
>>> e.append(prefix + "aaaaa" + "1".zfill(15) + suffix)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000002.0000000000')
True
>>> e = list(existing)
>>> e.append(prefix + "AAAAA" + "2".zfill(15) + suffix)
>>> handleClash1(userName="A" * 5, existing=e,
... prefix=prefix, suffix=suffix) == (
... '00000.AAAAA000000000000001.0000000000')
True
"""
# if the prefix length + user name length + suffix length + 15 is at
# or past the maximum length, silce 15 characters off of the user name
prefixLength = len(prefix)
suffixLength = len(suffix)
if prefixLength + len(userName) + suffixLength + 15 > maxFileNameLength:
l = prefixLength + len(userName) + suffixLength + 15
sliceLength = maxFileNameLength - l
userName = userName[:sliceLength]
finalName = None
# try to add numbers to create a unique name
counter = 1
while finalName is None:
name = userName + str(counter).zfill(15)
fullName = prefix + name + suffix
if fullName.lower() not in existing:
finalName = fullName
break
else:
counter += 1
if counter >= 999999999999999:
break
# if there is a clash, go to the next fallback
if finalName is None:
finalName = handleClash2(existing, prefix, suffix)
# finished
return finalName
def handleClash2(existing=[], prefix="", suffix=""):
"""
existing should be a case-insensitive list
of all existing file names.
>>> prefix = ("0" * 5) + "."
>>> suffix = "." + ("0" * 10)
>>> existing = [prefix + str(i) + suffix for i in range(100)]
>>> e = list(existing)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.100.0000000000')
True
>>> e = list(existing)
>>> e.remove(prefix + "1" + suffix)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.1.0000000000')
True
>>> e = list(existing)
>>> e.remove(prefix + "2" + suffix)
>>> handleClash2(existing=e, prefix=prefix, suffix=suffix) == (
... '00000.2.0000000000')
True
"""
# calculate the longest possible string
maxLength = maxFileNameLength - len(prefix) - len(suffix)
maxValue = int("9" * maxLength)
# try to find a number
finalName = None
counter = 1
while finalName is None:
fullName = prefix + str(counter) + suffix
if fullName.lower() not in existing:
finalName = fullName
break
else:
counter += 1
if counter >= maxValue:
break
# raise an error if nothing has been found
if finalName is None:
raise NameTranslationError("No unique name could be found.")
# finished
return finalName
if __name__ == "__main__":
import doctest
import sys
sys.exit(doctest.testmod().failed)
|