1 """Utilities for comparing files and directories.
2
3 Classes:
4 dircmp
5
6 Functions:
7 cmp(f1, f2, shallow=True) -> int
8 cmpfiles(a, b, common) -> ([], [], [])
9 clear_cache()
10
11 """
12
13 import os
14 import stat
15 from itertools import filterfalse
16 from types import GenericAlias
17
18 __all__ = ['clear_cache', 'cmp', 'dircmp', 'cmpfiles', 'DEFAULT_IGNORES']
19
20 _cache = {}
21 BUFSIZE = 8*1024
22
23 DEFAULT_IGNORES = [
24 'RCS', 'CVS', 'tags', '.git', '.hg', '.bzr', '_darcs', '__pycache__']
25
26 def clear_cache():
27 """Clear the filecmp cache."""
28 _cache.clear()
29
30 def cmp(f1, f2, shallow=True):
31 """Compare two files.
32
33 Arguments:
34
35 f1 -- First file name
36
37 f2 -- Second file name
38
39 shallow -- treat files as identical if their stat signatures (type, size,
40 mtime) are identical. Otherwise, files are considered different
41 if their sizes or contents differ. [default: True]
42
43 Return value:
44
45 True if the files are the same, False otherwise.
46
47 This function uses a cache for past comparisons and the results,
48 with cache entries invalidated if their stat information
49 changes. The cache may be cleared by calling clear_cache().
50
51 """
52
53 s1 = _sig(os.stat(f1))
54 s2 = _sig(os.stat(f2))
55 if s1[0] != stat.S_IFREG or s2[0] != stat.S_IFREG:
56 return False
57 if shallow and s1 == s2:
58 return True
59 if s1[1] != s2[1]:
60 return False
61
62 outcome = _cache.get((f1, f2, s1, s2))
63 if outcome is None:
64 outcome = _do_cmp(f1, f2)
65 if len(_cache) > 100: # limit the maximum size of the cache
66 clear_cache()
67 _cache[f1, f2, s1, s2] = outcome
68 return outcome
69
70 def _sig(st):
71 return (stat.S_IFMT(st.st_mode),
72 st.st_size,
73 st.st_mtime)
74
75 def _do_cmp(f1, f2):
76 bufsize = BUFSIZE
77 with open(f1, 'rb') as fp1, open(f2, 'rb') as fp2:
78 while True:
79 b1 = fp1.read(bufsize)
80 b2 = fp2.read(bufsize)
81 if b1 != b2:
82 return False
83 if not b1:
84 return True
85
86 # Directory comparison class.
87 #
88 class ESC[4;38;5;81mdircmp:
89 """A class that manages the comparison of 2 directories.
90
91 dircmp(a, b, ignore=None, hide=None)
92 A and B are directories.
93 IGNORE is a list of names to ignore,
94 defaults to DEFAULT_IGNORES.
95 HIDE is a list of names to hide,
96 defaults to [os.curdir, os.pardir].
97
98 High level usage:
99 x = dircmp(dir1, dir2)
100 x.report() -> prints a report on the differences between dir1 and dir2
101 or
102 x.report_partial_closure() -> prints report on differences between dir1
103 and dir2, and reports on common immediate subdirectories.
104 x.report_full_closure() -> like report_partial_closure,
105 but fully recursive.
106
107 Attributes:
108 left_list, right_list: The files in dir1 and dir2,
109 filtered by hide and ignore.
110 common: a list of names in both dir1 and dir2.
111 left_only, right_only: names only in dir1, dir2.
112 common_dirs: subdirectories in both dir1 and dir2.
113 common_files: files in both dir1 and dir2.
114 common_funny: names in both dir1 and dir2 where the type differs between
115 dir1 and dir2, or the name is not stat-able.
116 same_files: list of identical files.
117 diff_files: list of filenames which differ.
118 funny_files: list of files which could not be compared.
119 subdirs: a dictionary of dircmp instances (or MyDirCmp instances if this
120 object is of type MyDirCmp, a subclass of dircmp), keyed by names
121 in common_dirs.
122 """
123
124 def __init__(self, a, b, ignore=None, hide=None): # Initialize
125 self.left = a
126 self.right = b
127 if hide is None:
128 self.hide = [os.curdir, os.pardir] # Names never to be shown
129 else:
130 self.hide = hide
131 if ignore is None:
132 self.ignore = DEFAULT_IGNORES
133 else:
134 self.ignore = ignore
135
136 def phase0(self): # Compare everything except common subdirectories
137 self.left_list = _filter(os.listdir(self.left),
138 self.hide+self.ignore)
139 self.right_list = _filter(os.listdir(self.right),
140 self.hide+self.ignore)
141 self.left_list.sort()
142 self.right_list.sort()
143
144 def phase1(self): # Compute common names
145 a = dict(zip(map(os.path.normcase, self.left_list), self.left_list))
146 b = dict(zip(map(os.path.normcase, self.right_list), self.right_list))
147 self.common = list(map(a.__getitem__, filter(b.__contains__, a)))
148 self.left_only = list(map(a.__getitem__, filterfalse(b.__contains__, a)))
149 self.right_only = list(map(b.__getitem__, filterfalse(a.__contains__, b)))
150
151 def phase2(self): # Distinguish files, directories, funnies
152 self.common_dirs = []
153 self.common_files = []
154 self.common_funny = []
155
156 for x in self.common:
157 a_path = os.path.join(self.left, x)
158 b_path = os.path.join(self.right, x)
159
160 ok = True
161 try:
162 a_stat = os.stat(a_path)
163 except OSError:
164 # print('Can\'t stat', a_path, ':', why.args[1])
165 ok = False
166 try:
167 b_stat = os.stat(b_path)
168 except OSError:
169 # print('Can\'t stat', b_path, ':', why.args[1])
170 ok = False
171
172 if ok:
173 a_type = stat.S_IFMT(a_stat.st_mode)
174 b_type = stat.S_IFMT(b_stat.st_mode)
175 if a_type != b_type:
176 self.common_funny.append(x)
177 elif stat.S_ISDIR(a_type):
178 self.common_dirs.append(x)
179 elif stat.S_ISREG(a_type):
180 self.common_files.append(x)
181 else:
182 self.common_funny.append(x)
183 else:
184 self.common_funny.append(x)
185
186 def phase3(self): # Find out differences between common files
187 xx = cmpfiles(self.left, self.right, self.common_files)
188 self.same_files, self.diff_files, self.funny_files = xx
189
190 def phase4(self): # Find out differences between common subdirectories
191 # A new dircmp (or MyDirCmp if dircmp was subclassed) object is created
192 # for each common subdirectory,
193 # these are stored in a dictionary indexed by filename.
194 # The hide and ignore properties are inherited from the parent
195 self.subdirs = {}
196 for x in self.common_dirs:
197 a_x = os.path.join(self.left, x)
198 b_x = os.path.join(self.right, x)
199 self.subdirs[x] = self.__class__(a_x, b_x, self.ignore, self.hide)
200
201 def phase4_closure(self): # Recursively call phase4() on subdirectories
202 self.phase4()
203 for sd in self.subdirs.values():
204 sd.phase4_closure()
205
206 def report(self): # Print a report on the differences between a and b
207 # Output format is purposely lousy
208 print('diff', self.left, self.right)
209 if self.left_only:
210 self.left_only.sort()
211 print('Only in', self.left, ':', self.left_only)
212 if self.right_only:
213 self.right_only.sort()
214 print('Only in', self.right, ':', self.right_only)
215 if self.same_files:
216 self.same_files.sort()
217 print('Identical files :', self.same_files)
218 if self.diff_files:
219 self.diff_files.sort()
220 print('Differing files :', self.diff_files)
221 if self.funny_files:
222 self.funny_files.sort()
223 print('Trouble with common files :', self.funny_files)
224 if self.common_dirs:
225 self.common_dirs.sort()
226 print('Common subdirectories :', self.common_dirs)
227 if self.common_funny:
228 self.common_funny.sort()
229 print('Common funny cases :', self.common_funny)
230
231 def report_partial_closure(self): # Print reports on self and on subdirs
232 self.report()
233 for sd in self.subdirs.values():
234 print()
235 sd.report()
236
237 def report_full_closure(self): # Report on self and subdirs recursively
238 self.report()
239 for sd in self.subdirs.values():
240 print()
241 sd.report_full_closure()
242
243 methodmap = dict(subdirs=phase4,
244 same_files=phase3, diff_files=phase3, funny_files=phase3,
245 common_dirs=phase2, common_files=phase2, common_funny=phase2,
246 common=phase1, left_only=phase1, right_only=phase1,
247 left_list=phase0, right_list=phase0)
248
249 def __getattr__(self, attr):
250 if attr not in self.methodmap:
251 raise AttributeError(attr)
252 self.methodmap[attr](self)
253 return getattr(self, attr)
254
255 __class_getitem__ = classmethod(GenericAlias)
256
257
258 def cmpfiles(a, b, common, shallow=True):
259 """Compare common files in two directories.
260
261 a, b -- directory names
262 common -- list of file names found in both directories
263 shallow -- if true, do comparison based solely on stat() information
264
265 Returns a tuple of three lists:
266 files that compare equal
267 files that are different
268 filenames that aren't regular files.
269
270 """
271 res = ([], [], [])
272 for x in common:
273 ax = os.path.join(a, x)
274 bx = os.path.join(b, x)
275 res[_cmp(ax, bx, shallow)].append(x)
276 return res
277
278
279 # Compare two files.
280 # Return:
281 # 0 for equal
282 # 1 for different
283 # 2 for funny cases (can't stat, etc.)
284 #
285 def _cmp(a, b, sh, abs=abs, cmp=cmp):
286 try:
287 return not abs(cmp(a, b, sh))
288 except OSError:
289 return 2
290
291
292 # Return a copy with items that occur in skip removed.
293 #
294 def _filter(flist, skip):
295 return list(filterfalse(skip.__contains__, flist))
296
297
298 # Demonstration and testing.
299 #
300 def demo():
301 import sys
302 import getopt
303 options, args = getopt.getopt(sys.argv[1:], 'r')
304 if len(args) != 2:
305 raise getopt.GetoptError('need exactly two args', None)
306 dd = dircmp(args[0], args[1])
307 if ('-r', '') in options:
308 dd.report_full_closure()
309 else:
310 dd.report()
311
312 if __name__ == '__main__':
313 demo()