summaryrefslogtreecommitdiffstats
path: root/Lib/site.py
blob: dabd364ab59c2f57219412c87b0f991c251c4659 (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
"""Append module search paths for third-party packages to sys.path.

****************************************************************
* This module is automatically imported during initialization. *
****************************************************************

In earlier versions of Python (up to 1.5a3), scripts or modules that
needed to use site-specific modules would place ``import site''
somewhere near the top of their code.  Because of the automatic
import, this is no longer necessary (but code that does it still
works).

This will append site-specific paths to to the module search path.  On
Unix, it starts with sys.prefix and sys.exec_prefix (if different) and
appends lib/python<version>/site-packages as well as lib/site-python.
On other platforms (mainly Mac and Windows), it uses just sys.prefix
(and sys.exec_prefix, if different, but this is unlikely).  The
resulting directories, if they exist, are appended to sys.path, and
also inspected for path configuration files.

A path configuration file is a file whose name has the form
<package>.pth; its contents are additional directories (one per line)
to be added to sys.path.  Non-existing directories (or
non-directories) are never added to sys.path; no directory is added to
sys.path more than once.  Blank lines and lines beginning with
\code{#} are skipped.

For example, suppose sys.prefix and sys.exec_prefix are set to
/usr/local and there is a directory /usr/local/lib/python1.5/site-packages
with three subdirectories, foo, bar and spam, and two path
configuration files, foo.pth and bar.pth.  Assume foo.pth contains the
following:

  # foo package configuration
  foo
  bar
  bletch

and bar.pth contains:

  # bar package configuration
  bar

Then the following directories are added to sys.path, in this order:

  /usr/local/lib/python1.5/site-packages/bar
  /usr/local/lib/python1.5/site-packages/foo

Note that bletch is omitted because it doesn't exist; bar precedes foo
because bar.pth comes alphabetically before foo.pth; and spam is
omitted because it is not mentioned in either path configuration file.

After these path manipulations, an attempt is made to import a module
named sitecustomize, which can perform arbitrary additional
site-specific customizations.  If this import fails with an
ImportError exception, it is silently ignored.

"""

import sys, os

def addsitedir(sitedir):
    if sitedir not in sys.path:
        sys.path.append(sitedir)        # Add path component
    try:
        names = os.listdir(sitedir)
    except os.error:
        return
    names = map(os.path.normcase, names)
    names.sort()
    for name in names:
        if name[-4:] == ".pth":
            addpackage(sitedir, name)

def addpackage(sitedir, name):
    fullname = os.path.join(sitedir, name)
    try:
        f = open(fullname)
    except IOError:
        return
    while 1:
        dir = f.readline()
        if not dir:
            break
        if dir[0] == '#':
            continue
        if dir[-1] == '\n':
            dir = dir[:-1]
        dir = os.path.join(sitedir, dir)
        if dir not in sys.path and os.path.exists(dir):
            sys.path.append(dir)

prefixes = [sys.prefix]
if sys.exec_prefix != sys.prefix:
    prefixes.append(sys.exec_prefix)
for prefix in prefixes:
    if prefix:
        if os.sep == '/':
            sitedirs = [os.path.join(prefix,
                                     "lib",
                                     "python" + sys.version[:3],
                                     "site-packages"),
                        os.path.join(prefix, "lib", "site-python")]
        else:
            sitedirs = [prefix]
        for sitedir in sitedirs:
            if os.path.isdir(sitedir):
                addsitedir(sitedir)

# Define new built-ins 'quit' and 'exit'.
# These are simply strings that display a hint on how to exit.
if os.sep == ':':
    exit = 'Use Cmd-Q to quit.'
elif os.sep == '\\':
    exit = 'Use Ctrl-Z plus Return to exit.'
else:
    exit = 'Use Ctrl-D (i.e. EOF) to exit.'
import __builtin__
__builtin__.quit = __builtin__.exit = exit
del exit

#
# Set the string encoding used by the Unicode implementation to the
# encoding used by the default locale of this system. If the default
# encoding cannot be determined or is unkown, it defaults to 'ascii'.
#
def locale_aware_defaultencoding():
    import locale
    code, encoding = locale.get_default()
    if encoding is None:
        encoding = 'ascii'
    try:
        sys.setdefaultencoding(encoding)
    except LookupError:
        sys.setdefaultencoding('ascii')

if 1:
    # Enable to support locale aware default string encodings.
    locale_aware_defaultencoding()
elif 0:
    # Enable to switch off string to Unicode coercion and implicit
    # Unicode to string conversion.
    sys.setdefaultencoding('undefined')
elif 0:
    # Enable to hard-code a site specific default string encoding.
    sys.setdefaultencoding('ascii')

#
# Run custom site specific code, if available.
#
try:
    import sitecustomize
except ImportError:
    pass

#
# Remove sys.setdefaultencoding() so that users cannot change the
# encoding after initialization.
#
del sys.setdefaultencoding

def _test():
    print "sys.path = ["
    for dir in sys.path:
        print "    %s," % `dir`
    print "]"

if __name__ == '__main__':
    _test()