1 #
2 # distutils/version.py
3 #
4 # Implements multiple version numbering conventions for the
5 # Python Module Distribution Utilities.
6 #
7 # $Id$
8 #
9
10 """Provides classes to represent module version numbers (one class for
11 each style of version numbering). There are currently two such classes
12 implemented: StrictVersion and LooseVersion.
13
14 Every version number class implements the following interface:
15 * the 'parse' method takes a string and parses it to some internal
16 representation; if the string is an invalid version number,
17 'parse' raises a ValueError exception
18 * the class constructor takes an optional string argument which,
19 if supplied, is passed to 'parse'
20 * __str__ reconstructs the string that was passed to 'parse' (or
21 an equivalent string -- ie. one that will generate an equivalent
22 version number instance)
23 * __repr__ generates Python code to recreate the version number instance
24 * _cmp compares the current instance with either another instance
25 of the same class or a string (which will be parsed to an instance
26 of the same class, thus must follow the same rules)
27 """
28
29 import re
30
31 class ESC[4;38;5;81mVersion:
32 """Abstract base class for version numbering classes. Just provides
33 constructor (__init__) and reproducer (__repr__), because those
34 seem to be the same for all version numbering classes; and route
35 rich comparisons to _cmp.
36 """
37
38 def __init__ (self, vstring=None):
39 if vstring:
40 self.parse(vstring)
41
42 def __repr__ (self):
43 return "%s ('%s')" % (self.__class__.__name__, str(self))
44
45 def __eq__(self, other):
46 c = self._cmp(other)
47 if c is NotImplemented:
48 return c
49 return c == 0
50
51 def __lt__(self, other):
52 c = self._cmp(other)
53 if c is NotImplemented:
54 return c
55 return c < 0
56
57 def __le__(self, other):
58 c = self._cmp(other)
59 if c is NotImplemented:
60 return c
61 return c <= 0
62
63 def __gt__(self, other):
64 c = self._cmp(other)
65 if c is NotImplemented:
66 return c
67 return c > 0
68
69 def __ge__(self, other):
70 c = self._cmp(other)
71 if c is NotImplemented:
72 return c
73 return c >= 0
74
75
76 # Interface for version-number classes -- must be implemented
77 # by the following classes (the concrete ones -- Version should
78 # be treated as an abstract class).
79 # __init__ (string) - create and take same action as 'parse'
80 # (string parameter is optional)
81 # parse (string) - convert a string representation to whatever
82 # internal representation is appropriate for
83 # this style of version numbering
84 # __str__ (self) - convert back to a string; should be very similar
85 # (if not identical to) the string supplied to parse
86 # __repr__ (self) - generate Python code to recreate
87 # the instance
88 # _cmp (self, other) - compare two version numbers ('other' may
89 # be an unparsed version string, or another
90 # instance of your version class)
91
92
93 class ESC[4;38;5;81mStrictVersion (ESC[4;38;5;149mVersion):
94
95 """Version numbering for anal retentives and software idealists.
96 Implements the standard interface for version number classes as
97 described above. A version number consists of two or three
98 dot-separated numeric components, with an optional "pre-release" tag
99 on the end. The pre-release tag consists of the letter 'a' or 'b'
100 followed by a number. If the numeric components of two version
101 numbers are equal, then one with a pre-release tag will always
102 be deemed earlier (lesser) than one without.
103
104 The following are valid version numbers (shown in the order that
105 would be obtained by sorting according to the supplied cmp function):
106
107 0.4 0.4.0 (these two are equivalent)
108 0.4.1
109 0.5a1
110 0.5b3
111 0.5
112 0.9.6
113 1.0
114 1.0.4a3
115 1.0.4b1
116 1.0.4
117
118 The following are examples of invalid version numbers:
119
120 1
121 2.7.2.2
122 1.3.a4
123 1.3pl1
124 1.3c4
125
126 The rationale for this version numbering system will be explained
127 in the distutils documentation.
128 """
129
130 version_re = re.compile(r'^(\d+) \. (\d+) (\. (\d+))? ([ab](\d+))?$',
131 re.VERBOSE | re.ASCII)
132
133
134 def parse (self, vstring):
135 match = self.version_re.match(vstring)
136 if not match:
137 raise ValueError("invalid version number '%s'" % vstring)
138
139 (major, minor, patch, prerelease, prerelease_num) = \
140 match.group(1, 2, 4, 5, 6)
141
142 if patch:
143 self.version = tuple(map(int, [major, minor, patch]))
144 else:
145 self.version = tuple(map(int, [major, minor])) + (0,)
146
147 if prerelease:
148 self.prerelease = (prerelease[0], int(prerelease_num))
149 else:
150 self.prerelease = None
151
152
153 def __str__ (self):
154
155 if self.version[2] == 0:
156 vstring = '.'.join(map(str, self.version[0:2]))
157 else:
158 vstring = '.'.join(map(str, self.version))
159
160 if self.prerelease:
161 vstring = vstring + self.prerelease[0] + str(self.prerelease[1])
162
163 return vstring
164
165
166 def _cmp (self, other):
167 if isinstance(other, str):
168 other = StrictVersion(other)
169 elif not isinstance(other, StrictVersion):
170 return NotImplemented
171
172 if self.version != other.version:
173 # numeric versions don't match
174 # prerelease stuff doesn't matter
175 if self.version < other.version:
176 return -1
177 else:
178 return 1
179
180 # have to compare prerelease
181 # case 1: neither has prerelease; they're equal
182 # case 2: self has prerelease, other doesn't; other is greater
183 # case 3: self doesn't have prerelease, other does: self is greater
184 # case 4: both have prerelease: must compare them!
185
186 if (not self.prerelease and not other.prerelease):
187 return 0
188 elif (self.prerelease and not other.prerelease):
189 return -1
190 elif (not self.prerelease and other.prerelease):
191 return 1
192 elif (self.prerelease and other.prerelease):
193 if self.prerelease == other.prerelease:
194 return 0
195 elif self.prerelease < other.prerelease:
196 return -1
197 else:
198 return 1
199 else:
200 assert False, "never get here"
201
202 # end class StrictVersion
203
204
205 # The rules according to Greg Stein:
206 # 1) a version number has 1 or more numbers separated by a period or by
207 # sequences of letters. If only periods, then these are compared
208 # left-to-right to determine an ordering.
209 # 2) sequences of letters are part of the tuple for comparison and are
210 # compared lexicographically
211 # 3) recognize the numeric components may have leading zeroes
212 #
213 # The LooseVersion class below implements these rules: a version number
214 # string is split up into a tuple of integer and string components, and
215 # comparison is a simple tuple comparison. This means that version
216 # numbers behave in a predictable and obvious way, but a way that might
217 # not necessarily be how people *want* version numbers to behave. There
218 # wouldn't be a problem if people could stick to purely numeric version
219 # numbers: just split on period and compare the numbers as tuples.
220 # However, people insist on putting letters into their version numbers;
221 # the most common purpose seems to be:
222 # - indicating a "pre-release" version
223 # ('alpha', 'beta', 'a', 'b', 'pre', 'p')
224 # - indicating a post-release patch ('p', 'pl', 'patch')
225 # but of course this can't cover all version number schemes, and there's
226 # no way to know what a programmer means without asking him.
227 #
228 # The problem is what to do with letters (and other non-numeric
229 # characters) in a version number. The current implementation does the
230 # obvious and predictable thing: keep them as strings and compare
231 # lexically within a tuple comparison. This has the desired effect if
232 # an appended letter sequence implies something "post-release":
233 # eg. "0.99" < "0.99pl14" < "1.0", and "5.001" < "5.001m" < "5.002".
234 #
235 # However, if letters in a version number imply a pre-release version,
236 # the "obvious" thing isn't correct. Eg. you would expect that
237 # "1.5.1" < "1.5.2a2" < "1.5.2", but under the tuple/lexical comparison
238 # implemented here, this just isn't so.
239 #
240 # Two possible solutions come to mind. The first is to tie the
241 # comparison algorithm to a particular set of semantic rules, as has
242 # been done in the StrictVersion class above. This works great as long
243 # as everyone can go along with bondage and discipline. Hopefully a
244 # (large) subset of Python module programmers will agree that the
245 # particular flavour of bondage and discipline provided by StrictVersion
246 # provides enough benefit to be worth using, and will submit their
247 # version numbering scheme to its domination. The free-thinking
248 # anarchists in the lot will never give in, though, and something needs
249 # to be done to accommodate them.
250 #
251 # Perhaps a "moderately strict" version class could be implemented that
252 # lets almost anything slide (syntactically), and makes some heuristic
253 # assumptions about non-digits in version number strings. This could
254 # sink into special-case-hell, though; if I was as talented and
255 # idiosyncratic as Larry Wall, I'd go ahead and implement a class that
256 # somehow knows that "1.2.1" < "1.2.2a2" < "1.2.2" < "1.2.2pl3", and is
257 # just as happy dealing with things like "2g6" and "1.13++". I don't
258 # think I'm smart enough to do it right though.
259 #
260 # In any case, I've coded the test suite for this module (see
261 # ../test/test_version.py) specifically to fail on things like comparing
262 # "1.2a2" and "1.2". That's not because the *code* is doing anything
263 # wrong, it's because the simple, obvious design doesn't match my
264 # complicated, hairy expectations for real-world version numbers. It
265 # would be a snap to fix the test suite to say, "Yep, LooseVersion does
266 # the Right Thing" (ie. the code matches the conception). But I'd rather
267 # have a conception that matches common notions about version numbers.
268
269 class ESC[4;38;5;81mLooseVersion (ESC[4;38;5;149mVersion):
270
271 """Version numbering for anarchists and software realists.
272 Implements the standard interface for version number classes as
273 described above. A version number consists of a series of numbers,
274 separated by either periods or strings of letters. When comparing
275 version numbers, the numeric components will be compared
276 numerically, and the alphabetic components lexically. The following
277 are all valid version numbers, in no particular order:
278
279 1.5.1
280 1.5.2b2
281 161
282 3.10a
283 8.02
284 3.4j
285 1996.07.12
286 3.2.pl0
287 3.1.1.6
288 2g6
289 11g
290 0.960923
291 2.2beta29
292 1.13++
293 5.5.kw
294 2.0b1pl0
295
296 In fact, there is no such thing as an invalid version number under
297 this scheme; the rules for comparison are simple and predictable,
298 but may not always give the results you want (for some definition
299 of "want").
300 """
301
302 component_re = re.compile(r'(\d+ | [a-z]+ | \.)', re.VERBOSE)
303
304 def __init__ (self, vstring=None):
305 if vstring:
306 self.parse(vstring)
307
308
309 def parse (self, vstring):
310 # I've given up on thinking I can reconstruct the version string
311 # from the parsed tuple -- so I just store the string here for
312 # use by __str__
313 self.vstring = vstring
314 components = [x for x in self.component_re.split(vstring)
315 if x and x != '.']
316 for i, obj in enumerate(components):
317 try:
318 components[i] = int(obj)
319 except ValueError:
320 pass
321
322 self.version = components
323
324
325 def __str__ (self):
326 return self.vstring
327
328
329 def __repr__ (self):
330 return "LooseVersion ('%s')" % str(self)
331
332
333 def _cmp (self, other):
334 if isinstance(other, str):
335 other = LooseVersion(other)
336 elif not isinstance(other, LooseVersion):
337 return NotImplemented
338
339 if self.version == other.version:
340 return 0
341 if self.version < other.version:
342 return -1
343 if self.version > other.version:
344 return 1
345
346
347 # end class LooseVersion