summaryrefslogtreecommitdiffstats
path: root/Lib/filecmp.py
blob: 328528871ade8c79a83fa9d9e573a77c91a1bc58 (plain)
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
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
"""Utilities for comparing files and directories.

Classes:
    dircmp

Functions:
    cmp(f1, f2, shallow=True) -> int
    cmpfiles(a, b, common) -> ([], [], [])
    clear_cache()

"""

import os
import stat
from itertools import filterfalse

__all__ = ['clear_cache', 'cmp', 'dircmp', 'cmpfiles', 'DEFAULT_IGNORES']

_cache = {}
BUFSIZE = 8*1024

DEFAULT_IGNORES = [
    'RCS', 'CVS', 'tags', '.git', '.hg', '.bzr', '_darcs', '__pycache__']

def clear_cache():
    """Clear the filecmp cache."""
    _cache.clear()

def cmp(f1, f2, shallow=True):
    """Compare two files.

    Arguments:

    f1 -- First file name

    f2 -- Second file name

    shallow -- Just check stat signature (do not read the files).
               defaults to 1.

    Return value:

    True if the files are the same, False otherwise.

    This function uses a cache for past comparisons and the results,
    with a cache invalidation mechanism relying on stale signatures
    or by explicitly calling clear_cache().

    """

    s1 = _sig(os.stat(f1))
    s2 = _sig(os.stat(f2))
    if s1[0] != stat.S_IFREG or s2[0] != stat.S_IFREG:
        return False
    if shallow and s1 == s2:
        return True
    if s1[1] != s2[1]:
        return False

    outcome = _cache.get((f1, f2, s1, s2))
    if outcome is None:
        outcome = _do_cmp(f1, f2)
        if len(_cache) > 100:      # limit the maximum size of the cache
            clear_cache()
        _cache[f1, f2, s1, s2] = outcome
    return outcome

def _sig(st):
    return (stat.S_IFMT(st.st_mode),
            st.st_size,
            st.st_mtime)

def _do_cmp(f1, f2):
    bufsize = BUFSIZE
    with open(f1, 'rb') as fp1, open(f2, 'rb') as fp2:
        while True:
            b1 = fp1.read(bufsize)
            b2 = fp2.read(bufsize)
            if b1 != b2:
                return False
            if not b1:
                return True

# Directory comparison class.
#
class dircmp:
    """A class that manages the comparison of 2 directories.

    dircmp(a, b, ignore=None, hide=None)
      A and B are directories.
      IGNORE is a list of names to ignore,
        defaults to DEFAULT_IGNORES.
      HIDE is a list of names to hide,
        defaults to [os.curdir, os.pardir].

    High level usage:
      x = dircmp(dir1, dir2)
      x.report() -> prints a report on the differences between dir1 and dir2
       or
      x.report_partial_closure() -> prints report on differences between dir1
            and dir2, and reports on common immediate subdirectories.
      x.report_full_closure() -> like report_partial_closure,
            but fully recursive.

    Attributes:
     left_list, right_list: The files in dir1 and dir2,
        filtered by hide and ignore.
     common: a list of names in both dir1 and dir2.
     left_only, right_only: names only in dir1, dir2.
     common_dirs: subdirectories in both dir1 and dir2.
     common_files: files in both dir1 and dir2.
     common_funny: names in both dir1 and dir2 where the type differs between
        dir1 and dir2, or the name is not stat-able.
     same_files: list of identical files.
     diff_files: list of filenames which differ.
     funny_files: list of files which could not be compared.
     subdirs: a dictionary of dircmp objects, keyed by names in common_dirs.
     """

    def __init__(self, a, b, ignore=None, hide=None): # Initialize
        self.left = a
        self.right = b
        if hide is None:
            self.hide = [os.curdir, os.pardir] # Names never to be shown
        else:
            self.hide = hide
        if ignore is None:
            self.ignore = DEFAULT_IGNORES
        else:
            self.ignore = ignore

    def phase0(self): # Compare everything except common subdirectories
        self.left_list = _filter(os.listdir(self.left),
                                 self.hide+self.ignore)
        self.right_list = _filter(os.listdir(self.right),
                                  self.hide+self.ignore)
        self.left_list.sort()
        self.right_list.sort()

    def phase1(self): # Compute common names
        a = dict(zip(map(os.path.normcase, self.left_list), self.left_list))
        b = dict(zip(map(os.path.normcase, self.right_list), self.right_list))
        self.common = list(map(a.__getitem__, filter(b.__contains__, a)))
        self.left_only = list(map(a.__getitem__, filterfalse(b.__contains__, a)))
        self.right_only = list(map(b.__getitem__, filterfalse(a.__contains__, b)))

    def phase2(self): # Distinguish files, directories, funnies
        self.common_dirs = []
        self.common_files = []
        self.common_funny = []

        for x in self.common:
            a_path = os.path.join(self.left, x)
            b_path = os.path.join(self.right, x)

            ok = 1
            try:
                a_stat = os.stat(a_path)
            except OSError as why:
                # print('Can\'t stat', a_path, ':', why.args[1])
                ok = 0
            try:
                b_stat = os.stat(b_path)
            except OSError as why:
                # print('Can\'t stat', b_path, ':', why.args[1])
                ok = 0

            if ok:
                a_type = stat.S_IFMT(a_stat.st_mode)
                b_type = stat.S_IFMT(b_stat.st_mode)
                if a_type != b_type:
                    self.common_funny.append(x)
                elif stat.S_ISDIR(a_type):
                    self.common_dirs.append(x)
                elif stat.S_ISREG(a_type):
                    self.common_files.append(x)
                else:
                    self.common_funny.append(x)
            else:
                self.common_funny.append(x)

    def phase3(self): # Find out differences between common files
        xx = cmpfiles(self.left, self.right, self.common_files)
        self.same_files, self.diff_files, self.funny_files = xx

    def phase4(self): # Find out differences between common subdirectories
        # A new dircmp object is created for each common subdirectory,
        # these are stored in a dictionary indexed by filename.
        # The hide and ignore properties are inherited from the parent
        self.subdirs = {}
        for x in self.common_dirs:
            a_x = os.path.join(self.left, x)
            b_x = os.path.join(self.right, x)
            self.subdirs[x]  = dircmp(a_x, b_x, self.ignore, self.hide)

    def phase4_closure(self): # Recursively call phase4() on subdirectories
        self.phase4()
        for sd in self.subdirs.values():
            sd.phase4_closure()

    def report(self): # Print a report on the differences between a and b
        # Output format is purposely lousy
        print('diff', self.left, self.right)
        if self.left_only:
            self.left_only.sort()
            print('Only in', self.left, ':', self.left_only)
        if self.right_only:
            self.right_only.sort()
            print('Only in', self.right, ':', self.right_only)
        if self.same_files:
            self.same_files.sort()
            print('Identical files :', self.same_files)
        if self.diff_files:
            self.diff_files.sort()
            print('Differing files :', self.diff_files)
        if self.funny_files:
            self.funny_files.sort()
            print('Trouble with common files :', self.funny_files)
        if self.common_dirs:
            self.common_dirs.sort()
            print('Common subdirectories :', self.common_dirs)
        if self.common_funny:
            self.common_funny.sort()
            print('Common funny cases :', self.common_funny)

    def report_partial_closure(self): # Print reports on self and on subdirs
        self.report()
        for sd in self.subdirs.values():
            print()
            sd.report()

    def report_full_closure(self): # Report on self and subdirs recursively
        self.report()
        for sd in self.subdirs.values():
            print()
            sd.report_full_closure()

    methodmap = dict(subdirs=phase4,
                     same_files=phase3, diff_files=phase3, funny_files=phase3,
                     common_dirs = phase2, common_files=phase2, common_funny=phase2,
                     common=phase1, left_only=phase1, right_only=phase1,
                     left_list=phase0, right_list=phase0)

    def __getattr__(self, attr):
        if attr not in self.methodmap:
            raise AttributeError(attr)
        self.methodmap[attr](self)
        return getattr(self, attr)

def cmpfiles(a, b, common, shallow=True):
    """Compare common files in two directories.

    a, b -- directory names
    common -- list of file names found in both directories
    shallow -- if true, do comparison based solely on stat() information

    Returns a tuple of three lists:
      files that compare equal
      files that are different
      filenames that aren't regular files.

    """
    res = ([], [], [])
    for x in common:
        ax = os.path.join(a, x)
        bx = os.path.join(b, x)
        res[_cmp(ax, bx, shallow)].append(x)
    return res


# Compare two files.
# Return:
#       0 for equal
#       1 for different
#       2 for funny cases (can't stat, etc.)
#
def _cmp(a, b, sh, abs=abs, cmp=cmp):
    try:
        return not abs(cmp(a, b, sh))
    except OSError:
        return 2


# Return a copy with items that occur in skip removed.
#
def _filter(flist, skip):
    return list(filterfalse(skip.__contains__, flist))


# Demonstration and testing.
#
def demo():
    import sys
    import getopt
    options, args = getopt.getopt(sys.argv[1:], 'r')
    if len(args) != 2:
        raise getopt.GetoptError('need exactly two args', None)
    dd = dircmp(args[0], args[1])
    if ('-r', '') in options:
        dd.report_full_closure()
    else:
        dd.report()

if __name__ == '__main__':
    demo()