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
|
# Module 'path' -- common operations on POSIX pathnames
import posix
import stat
# Join two pathnames.
# Insert a '/' unless the first part is empty or already ends in '/'.
# Ignore the first part altogether if the second part is absolute
# (begins with '/').
#
def join(a, b):
if b[:1] = '/': return b
if a = '' or a[-1:] = '/': return a + b
# Note: join('x', '') returns 'x/'; is this what we want?
return a + '/' + b
cat = join # For compatibility
# Split a path in head (empty or ending in '/') and tail (no '/').
# The tail will be empty if the path ends in '/'.
# It is always true that head+tail = p.
#
def split(p):
head, tail = '', ''
for c in p:
tail = tail + c
if c = '/':
head, tail = head + tail, ''
return head, tail
# Split a path in root and extension.
# The extension is everything starting at the first dot in the last
# pathname component; the root is everything before that.
# It is always true that root+ext = p.
#
def splitext(p):
root, ext = '', ''
for c in p:
if c = '/':
root, ext = root + ext + c, ''
elif c = '.' or ext:
ext = ext + c
else:
root = root + c
return root, ext
# Return the tail (basename) part of a path.
#
def basename(p):
return split(p)[1]
# Return the longest prefix of all list elements.
#
def commonprefix(m):
if not m: return ''
prefix = m[0]
for item in m:
for i in range(len(prefix)):
if prefix[:i+1] <> item[:i+1]:
prefix = prefix[:i]
if i = 0: return ''
break
return prefix
# Does a file/directory exist?
#
def exists(path):
try:
st = posix.stat(path)
except posix.error:
return 0
return 1
# Is a path a posix directory?
#
def isdir(path):
try:
st = posix.stat(path)
except posix.error:
return 0
return stat.S_ISDIR(st[stat.ST_MODE])
# Is a path a symbolic link?
# This will always return false on systems where posix.lstat doesn't exist.
#
def islink(path):
try:
st = posix.lstat(path)
except (posix.error, NameError):
return 0
return stat.S_ISLNK(st[stat.ST_MODE])
# Are two filenames really pointing to the same file?
#
def samefile(f1, f2):
s1 = posix.stat(f1)
s2 = posix.stat(f2)
return samestat(s1, s2)
# Are two open files really referencing the same file?
# (Not necessarily the same file descriptor!)
# XXX Oops, posix.fstat() doesn't exist yet!
#
def sameopenfile(fp1, fp2):
s1 = posix.fstat(fp1)
s2 = posix.fstat(fp2)
return samestat(s1, s2)
# Are two stat buffers (obtained from stat, fstat or lstat)
# describing the same file?
#
def samestat(s1, s2):
return s1[stat.ST_INO] = s2[stat.ST_INO] and \
s1[stat.ST_DEV] = s2[stat.STD_DEV]
# Subroutine and global data used by ismount().
_mounts = []
def _getmounts():
import commands, string
mounts = []
data = commands.getoutput('/etc/mount')
lines = string.splitfields(data, '\n')
for line in lines:
words = string.split(line)
if len(words) >= 3 and words[1] = 'on':
mounts.append(words[2])
return mounts
# Is a path a mount point?
# This only works for normalized, absolute paths,
# and only if the mount table as printed by /etc/mount is correct.
# Sorry.
#
def ismount(path):
if not _mounts:
_mounts[:] = _getmounts()
return path in _mounts
# Directory tree walk.
# For each directory under top (including top itself),
# func(arg, dirname, filenames) is called, where dirname
# is the name of the directory and filenames is the list of
# files (and subdirectories etc.) in the directory.
# func may modify the filenames list, to implement a filter,
# or to impose a different order of visiting.
#
def walk(top, func, arg):
try:
names = posix.listdir(top)
except posix.error:
return
func(arg, top, names)
exceptions = ('.', '..')
for name in names:
if name not in exceptions:
name = join(top, name)
if isdir(name):
walk(name, func, arg)
|
