~gary/zc.buildout/python-support-4

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
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
#############################################################################
#
# Copyright (c) 2005 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################
"""Python easy_install API

This module provides a high-level Python API for installing packages.
It doesn't install scripts.  It uses setuptools and requires it to be
installed.
"""

import distutils.errors
import glob
import logging
import os
import pkg_resources
import py_compile
import re
import setuptools.archive_util
import setuptools.command.setopt
import setuptools.package_index
import shutil
import subprocess
import sys
import tempfile
import zc.buildout
import zipimport

_oprp = getattr(os.path, 'realpath', lambda path: path)
def realpath(path):
    return os.path.normcase(os.path.abspath(_oprp(path)))

default_index_url = os.environ.get(
    'buildout-testing-index-url',
    'http://pypi.python.org/simple',
    )

logger = logging.getLogger('zc.buildout.easy_install')

url_match = re.compile('[a-z0-9+.-]+://').match

is_win32 = sys.platform == 'win32'
is_jython = sys.platform.startswith('java')

if is_jython:
    import java.lang.System
    jython_os_name = (java.lang.System.getProperties()['os.name']).lower()


setuptools_loc = pkg_resources.working_set.find(
    pkg_resources.Requirement.parse('setuptools')
    ).location

# Include buildout and setuptools eggs in paths.  We prevent dupes just to
# keep from duplicating any log messages about them.
buildout_loc = pkg_resources.working_set.find(
    pkg_resources.Requirement.parse('zc.buildout')).location
buildout_and_setuptools_path = [setuptools_loc]
if os.path.normpath(setuptools_loc) != os.path.normpath(buildout_loc):
    buildout_and_setuptools_path.append(buildout_loc)


class IncompatibleVersionError(zc.buildout.UserError):
    """A specified version is incompatible with a given requirement.
    """

_versions = {sys.executable: '%d.%d' % sys.version_info[:2]}
def _get_version(executable):
    try:
        return _versions[executable]
    except KeyError:
        cmd = _safe_arg(executable) + ' -V'
        p = subprocess.Popen(cmd,
                             shell=True,
                             stdin=subprocess.PIPE,
                             stdout=subprocess.PIPE,
                             stderr=subprocess.STDOUT,
                             close_fds=not is_win32)
        i, o = (p.stdin, p.stdout)
        i.close()
        version = o.read().strip()
        o.close()
        pystring, version = version.split()
        assert pystring == 'Python'
        version = re.match('(\d[.]\d)([.].*\d)?$', version).group(1)
        _versions[executable] = version
        return version

FILE_SCHEME = re.compile('file://', re.I).match


class AllowHostsPackageIndex(setuptools.package_index.PackageIndex):
    """Will allow urls that are local to the system.

    No matter what is allow_hosts.
    """
    def url_ok(self, url, fatal=False):
        if FILE_SCHEME(url):
            return True
        return setuptools.package_index.PackageIndex.url_ok(self, url, False)


_indexes = {}
def _get_index(executable, index_url, find_links, allow_hosts=('*',)):
    key = executable, index_url, tuple(find_links)
    index = _indexes.get(key)
    if index is not None:
        return index

    if index_url is None:
        index_url = default_index_url
    index = AllowHostsPackageIndex(
        index_url, hosts=allow_hosts, python=_get_version(executable)
        )

    if find_links:
        index.add_find_links(find_links)

    _indexes[key] = index
    return index

clear_index_cache = _indexes.clear

if is_win32:
    # work around spawn lamosity on windows
    # XXX need safe quoting (see the subproces.list2cmdline) and test
    def _safe_arg(arg):
        return '"%s"' % arg
else:
    _safe_arg = str

# The following string is used to run easy_install in
# Installer._call_easy_install.  It is started with python -S (that is,
# don't import site at start).  That flag, and all of the code in this
# snippet above the last two lines, exist to work around a relatively rare
# problem.  If
#
# - your buildout configuration is trying to install a package that is within
#   a namespace package, and
#
# - you use a Python that has a different version of this package
#   installed in in its site-packages using
#   --single-version-externally-managed (that is, using the mechanism
#   sometimes used by system packagers:
#   http://peak.telecommunity.com/DevCenter/setuptools#install-command ), and
#
# - the new package tries to do sys.path tricks in the setup.py to get a
#   __version__,
#
# then the older package will be loaded first, making the setup version
# the wrong number. While very arguably packages simply shouldn't do
# the sys.path tricks, some do, and we don't want buildout to fall over
# when they do.
#
# The namespace packages installed in site-packages with
# --single-version-externally-managed use a mechanism that cause them to
# be processed when site.py is imported  (see
# http://mail.python.org/pipermail/distutils-sig/2009-May/011730.html
# for another description of the problem).  Simply starting Python with
# -S addresses the problem in Python 2.4 and 2.5, but Python 2.6's
# distutils imports a value from the site module, so we unfortunately
# have to do more drastic surgery in the _easy_install_cmd code below.
#
# Here's an example of the .pth files created by setuptools when using that
# flag:
#
# import sys,new,os;
# p = os.path.join(sys._getframe(1).f_locals['sitedir'], *('<NAMESPACE>',));
# ie = os.path.exists(os.path.join(p,'__init__.py'));
# m = not ie and sys.modules.setdefault('<NAMESPACE>',new.module('<NAMESPACE>'));
# mp = (m or []) and m.__dict__.setdefault('__path__',[]);
# (p not in mp) and mp.append(p)
#
# The code, below, then, runs under -S, indicating that site.py should
# not be loaded initially.  It gets the initial sys.path under these
# circumstances, and then imports site (because Python 2.6's distutils
# will want it, as mentioned above). It then reinstates the old sys.path
# value. Then it removes namespace packages (created by the setuptools
# code above) from sys.modules.  It identifies namespace packages by
# iterating over every loaded module.  It first looks if there is a
# __path__, so it is a package; and then it sees if that __path__ does
# not have an __init__.py.  (Note that PEP 382,
# http://www.python.org/dev/peps/pep-0382, makes it possible to have a
# namespace package that has an __init__.py, but also should make it
# unnecessary for site.py to preprocess these packages, so it should be
# fine, as far as can be guessed as of this writing.)  Finally, it
# imports easy_install and runs it.

_easy_install_cmd = _safe_arg('''\
import sys,os;\
p = sys.path[:];\
import site;\
sys.path[:] = p;\
[sys.modules.pop(k) for k, v in sys.modules.items()\
 if hasattr(v, '__path__') and len(v.__path__)==1 and\
 not os.path.exists(os.path.join(v.__path__[0],'__init__.py'))];\
from setuptools.command.easy_install import main;\
main()''')


class Installer:

    _versions = {}
    _download_cache = None
    _install_from_cache = False
    _prefer_final = True
    _use_dependency_links = True
    _allow_picked_versions = True
    _always_unzip = False

    def __init__(self,
                 dest=None,
                 links=(),
                 index=None,
                 executable=sys.executable,
                 always_unzip=None,
                 path=None,
                 newest=True,
                 versions=None,
                 use_dependency_links=None,
                 allow_hosts=('*',)
                 ):
        self._dest = dest
        self._allow_hosts = allow_hosts

        if self._install_from_cache:
            if not self._download_cache:
                raise ValueError("install_from_cache set to true with no"
                                 " download cache")
            links = ()
            index = 'file://' + self._download_cache

        if use_dependency_links is not None:
            self._use_dependency_links = use_dependency_links
        self._links = links = list(_fix_file_links(links))
        if self._download_cache and (self._download_cache not in links):
            links.insert(0, self._download_cache)

        self._index_url = index
        self._executable = executable
        if always_unzip is not None:
            self._always_unzip = always_unzip
        path = (path and path[:] or []) + buildout_and_setuptools_path
        if dest is not None and dest not in path:
            path.insert(0, dest)
        self._path = path
        if self._dest is None:
            newest = False
        self._newest = newest
        self._env = pkg_resources.Environment(path,
                                              python=_get_version(executable))
        self._index = _get_index(executable, index, links, self._allow_hosts)

        if versions is not None:
            self._versions = versions

    def _satisfied(self, req, source=None):
        dists = [dist for dist in self._env[req.project_name] if dist in req]
        if not dists:
            logger.debug('We have no distributions for %s that satisfies %r.',
                         req.project_name, str(req))

            return None, self._obtain(req, source)

        # Note that dists are sorted from best to worst, as promised by
        # env.__getitem__

        for dist in dists:
            if (dist.precedence == pkg_resources.DEVELOP_DIST):
                logger.debug('We have a develop egg: %s', dist)
                return dist, None

        # Special common case, we have a specification for a single version:
        specs = req.specs
        if len(specs) == 1 and specs[0][0] == '==':
            logger.debug('We have the distribution that satisfies %r.',
                         str(req))
            return dists[0], None

        if self._prefer_final:
            fdists = [dist for dist in dists
                      if _final_version(dist.parsed_version)
                      ]
            if fdists:
                # There are final dists, so only use those
                dists = fdists

        if not self._newest:
            # We don't need the newest, so we'll use the newest one we
            # find, which is the first returned by
            # Environment.__getitem__.
            return dists[0], None

        best_we_have = dists[0] # Because dists are sorted from best to worst

        # We have some installed distros.  There might, theoretically, be
        # newer ones.  Let's find out which ones are available and see if
        # any are newer.  We only do this if we're willing to install
        # something, which is only true if dest is not None:

        if self._dest is not None:
            best_available = self._obtain(req, source)
        else:
            best_available = None

        if best_available is None:
            # That's a bit odd.  There aren't any distros available.
            # We should use the best one we have that meets the requirement.
            logger.debug(
                'There are no distros available that meet %r.\n'
                'Using our best, %s.',
                str(req), best_available)
            return best_we_have, None

        if self._prefer_final:
            if _final_version(best_available.parsed_version):
                if _final_version(best_we_have.parsed_version):
                    if (best_we_have.parsed_version
                        <
                        best_available.parsed_version
                        ):
                        return None, best_available
                else:
                    return None, best_available
            else:
                if (not _final_version(best_we_have.parsed_version)
                    and
                    (best_we_have.parsed_version
                     <
                     best_available.parsed_version
                     )
                    ):
                    return None, best_available
        else:
            if (best_we_have.parsed_version
                <
                best_available.parsed_version
                ):
                return None, best_available

        logger.debug(
            'We have the best distribution that satisfies %r.',
            str(req))
        return best_we_have, None

    def _load_dist(self, dist):
        dists = pkg_resources.Environment(
            dist.location,
            python=_get_version(self._executable),
            )[dist.project_name]
        assert len(dists) == 1
        return dists[0]

    def _call_easy_install(self, spec, ws, dest, dist):

        tmp = tempfile.mkdtemp(dir=dest)
        try:
            path = setuptools_loc

            args = ('-Sc', _easy_install_cmd, '-mUNxd', _safe_arg(tmp))
            if self._always_unzip:
                args += ('-Z', )
            level = logger.getEffectiveLevel()
            if level > 0:
                args += ('-q', )
            elif level < 0:
                args += ('-v', )

            args += (_safe_arg(spec), )

            if level <= logging.DEBUG:
                logger.debug('Running easy_install:\n%s "%s"\npath=%s\n',
                             self._executable, '" "'.join(args), path)

            if is_jython:
                extra_env = dict(os.environ, PYTHONPATH=path)
            else:
                args += (dict(os.environ, PYTHONPATH=path), )

            sys.stdout.flush() # We want any pending output first

            if is_jython:
                exit_code = subprocess.Popen(
                [_safe_arg(self._executable)] + list(args),
                env=extra_env).wait()
            else:
                exit_code = os.spawnle(
                    os.P_WAIT, self._executable, _safe_arg (self._executable),
                    *args)

            dists = []
            env = pkg_resources.Environment(
                [tmp],
                python=_get_version(self._executable),
                )
            for project in env:
                dists.extend(env[project])

            if exit_code:
                logger.error(
                    "An error occured when trying to install %s. "
                    "Look above this message for any errors that "
                    "were output by easy_install.",
                    dist)

            if not dists:
                raise zc.buildout.UserError("Couldn't install: %s" % dist)

            if len(dists) > 1:
                logger.warn("Installing %s\n"
                            "caused multiple distributions to be installed:\n"
                            "%s\n",
                            dist, '\n'.join(map(str, dists)))
            else:
                d = dists[0]
                if d.project_name != dist.project_name:
                    logger.warn("Installing %s\n"
                                "Caused installation of a distribution:\n"
                                "%s\n"
                                "with a different project name.",
                                dist, d)
                if d.version != dist.version:
                    logger.warn("Installing %s\n"
                                "Caused installation of a distribution:\n"
                                "%s\n"
                                "with a different version.",
                                dist, d)

            result = []
            for d in dists:
                newloc = os.path.join(dest, os.path.basename(d.location))
                if os.path.exists(newloc):
                    if os.path.isdir(newloc):
                        shutil.rmtree(newloc)
                    else:
                        os.remove(newloc)
                os.rename(d.location, newloc)

                [d] = pkg_resources.Environment(
                    [newloc],
                    python=_get_version(self._executable),
                    )[d.project_name]

                result.append(d)

            return result

        finally:
            shutil.rmtree(tmp)

    def _obtain(self, requirement, source=None):
        # initialize out index for this project:
        index = self._index

        if index.obtain(requirement) is None:
            # Nothing is available.
            return None

        # Filter the available dists for the requirement and source flag
        dists = [dist for dist in index[requirement.project_name]
                 if ((dist in requirement)
                     and
                     ((not source) or
                      (dist.precedence == pkg_resources.SOURCE_DIST)
                      )
                     )
                 ]

        # If we prefer final dists, filter for final and use the
        # result if it is non empty.
        if self._prefer_final:
            fdists = [dist for dist in dists
                      if _final_version(dist.parsed_version)
                      ]
            if fdists:
                # There are final dists, so only use those
                dists = fdists

        # Now find the best one:
        best = []
        bestv = ()
        for dist in dists:
            distv = dist.parsed_version
            if distv > bestv:
                best = [dist]
                bestv = distv
            elif distv == bestv:
                best.append(dist)

        if not best:
            return None

        if len(best) == 1:
            return best[0]

        if self._download_cache:
            for dist in best:
                if (realpath(os.path.dirname(dist.location))
                    ==
                    self._download_cache
                    ):
                    return dist

        best.sort()
        return best[-1]

    def _fetch(self, dist, tmp, download_cache):
        if (download_cache
            and (realpath(os.path.dirname(dist.location)) == download_cache)
            ):
            return dist

        new_location = self._index.download(dist.location, tmp)
        if (download_cache
            and (realpath(new_location) == realpath(dist.location))
            and os.path.isfile(new_location)
            ):
            # setuptools avoids making extra copies, but we want to copy
            # to the download cache
            shutil.copy2(new_location, tmp)
            new_location = os.path.join(tmp, os.path.basename(new_location))

        return dist.clone(location=new_location)

    def _get_dist(self, requirement, ws, always_unzip):

        __doing__ = 'Getting distribution for %r.', str(requirement)

        # Maybe an existing dist is already the best dist that satisfies the
        # requirement
        dist, avail = self._satisfied(requirement)

        if dist is None:
            if self._dest is not None:
                logger.info(*__doing__)

            # Retrieve the dist:
            if avail is None:
                raise MissingDistribution(requirement, ws)

            # We may overwrite distributions, so clear importer
            # cache.
            sys.path_importer_cache.clear()

            tmp = self._download_cache
            if tmp is None:
                tmp = tempfile.mkdtemp('get_dist')

            try:
                dist = self._fetch(avail, tmp, self._download_cache)

                if dist is None:
                    raise zc.buildout.UserError(
                        "Couldn't download distribution %s." % avail)

                if dist.precedence == pkg_resources.EGG_DIST:
                    # It's already an egg, just fetch it into the dest

                    newloc = os.path.join(
                        self._dest, os.path.basename(dist.location))

                    if os.path.isdir(dist.location):
                        # we got a directory. It must have been
                        # obtained locally.  Just copy it.
                        shutil.copytree(dist.location, newloc)
                    else:

                        if self._always_unzip:
                            should_unzip = True
                        else:
                            metadata = pkg_resources.EggMetadata(
                                zipimport.zipimporter(dist.location)
                                )
                            should_unzip = (
                                metadata.has_metadata('not-zip-safe')
                                or
                                not metadata.has_metadata('zip-safe')
                                )

                        if should_unzip:
                            setuptools.archive_util.unpack_archive(
                                dist.location, newloc)
                        else:
                            shutil.copyfile(dist.location, newloc)

                    redo_pyc(newloc)

                    # Getting the dist from the environment causes the
                    # distribution meta data to be read.  Cloning isn't
                    # good enough.
                    dists = pkg_resources.Environment(
                        [newloc],
                        python=_get_version(self._executable),
                        )[dist.project_name]
                else:
                    # It's some other kind of dist.  We'll let easy_install
                    # deal with it:
                    dists = self._call_easy_install(
                        dist.location, ws, self._dest, dist)
                    for dist in dists:
                        redo_pyc(dist.location)

            finally:
                if tmp != self._download_cache:
                    shutil.rmtree(tmp)

            self._env.scan([self._dest])
            dist = self._env.best_match(requirement, ws)
            logger.info("Got %s.", dist)

        else:
            dists = [dist]

        for dist in dists:
            if (dist.has_metadata('dependency_links.txt')
                and not self._install_from_cache
                and self._use_dependency_links
                ):
                for link in dist.get_metadata_lines('dependency_links.txt'):
                    link = link.strip()
                    if link not in self._links:
                        logger.debug('Adding find link %r from %s', link, dist)
                        self._links.append(link)
                        self._index = _get_index(self._executable,
                                                 self._index_url, self._links,
                                                 self._allow_hosts)

        for dist in dists:
            # Check whether we picked a version and, if we did, report it:
            if not (
                dist.precedence == pkg_resources.DEVELOP_DIST
                or
                (len(requirement.specs) == 1
                 and
                 requirement.specs[0][0] == '==')
                ):
                logger.debug('Picked: %s = %s',
                             dist.project_name, dist.version)
                if not self._allow_picked_versions:
                    raise zc.buildout.UserError(
                        'Picked: %s = %s' % (dist.project_name, dist.version)
                        )

        return dists

    def _maybe_add_setuptools(self, ws, dist):
        if dist.has_metadata('namespace_packages.txt'):
            for r in dist.requires():
                if r.project_name == 'setuptools':
                    break
            else:
                # We have a namespace package but no requirement for setuptools
                if dist.precedence == pkg_resources.DEVELOP_DIST:
                    logger.warn(
                        "Develop distribution: %s\n"
                        "uses namespace packages but the distribution "
                        "does not require setuptools.",
                        dist)
                requirement = self._constrain(
                    pkg_resources.Requirement.parse('setuptools')
                    )
                if ws.find(requirement) is None:
                    for dist in self._get_dist(requirement, ws, False):
                        ws.add(dist)


    def _constrain(self, requirement):
        version = self._versions.get(requirement.project_name)
        if version:
            if version not in requirement:
                logger.error("The version, %s, is not consistent with the "
                             "requirement, %r.", version, str(requirement))
                raise IncompatibleVersionError("Bad version", version)

            requirement = pkg_resources.Requirement.parse(
                "%s[%s] ==%s" % (requirement.project_name,
                               ','.join(requirement.extras),
                               version))

        return requirement

    def install(self, specs, working_set=None):

        logger.debug('Installing %s.', repr(specs)[1:-1])

        path = self._path
        destination = self._dest
        if destination is not None and destination not in path:
            path.insert(0, destination)

        requirements = [self._constrain(pkg_resources.Requirement.parse(spec))
                        for spec in specs]



        if working_set is None:
            ws = pkg_resources.WorkingSet([])
        else:
            ws = working_set

        for requirement in requirements:
            for dist in self._get_dist(requirement, ws, self._always_unzip):
                ws.add(dist)
                self._maybe_add_setuptools(ws, dist)

        # OK, we have the requested distributions and they're in the working
        # set, but they may have unmet requirements.  We'll simply keep
        # trying to resolve requirements, adding missing requirements as they
        # are reported.
        #
        # Note that we don't pass in the environment, because we want
        # to look for new eggs unless what we have is the best that
        # matches the requirement.
        while 1:
            try:
                ws.resolve(requirements)
            except pkg_resources.DistributionNotFound, err:
                [requirement] = err
                requirement = self._constrain(requirement)
                if destination:
                    logger.debug('Getting required %r', str(requirement))
                else:
                    logger.debug('Adding required %r', str(requirement))
                _log_requirement(ws, requirement)

                for dist in self._get_dist(requirement, ws, self._always_unzip
                                           ):

                    ws.add(dist)
                    self._maybe_add_setuptools(ws, dist)
            except pkg_resources.VersionConflict, err:
                raise VersionConflict(err, ws)
            else:
                break

        return ws

    def build(self, spec, build_ext):

        requirement = self._constrain(pkg_resources.Requirement.parse(spec))

        dist, avail = self._satisfied(requirement, 1)
        if dist is not None:
            return [dist.location]

        # Retrieve the dist:
        if avail is None:
            raise zc.buildout.UserError(
                "Couldn't find a source distribution for %r."
                % str(requirement))

        logger.debug('Building %r', spec)

        tmp = self._download_cache
        if tmp is None:
            tmp = tempfile.mkdtemp('get_dist')

        try:
            dist = self._fetch(avail, tmp, self._download_cache)

            build_tmp = tempfile.mkdtemp('build')
            try:
                setuptools.archive_util.unpack_archive(dist.location,
                                                       build_tmp)
                if os.path.exists(os.path.join(build_tmp, 'setup.py')):
                    base = build_tmp
                else:
                    setups = glob.glob(
                        os.path.join(build_tmp, '*', 'setup.py'))
                    if not setups:
                        raise distutils.errors.DistutilsError(
                            "Couldn't find a setup script in %s"
                            % os.path.basename(dist.location)
                            )
                    if len(setups) > 1:
                        raise distutils.errors.DistutilsError(
                            "Multiple setup scripts in %s"
                            % os.path.basename(dist.location)
                            )
                    base = os.path.dirname(setups[0])

                setup_cfg = os.path.join(base, 'setup.cfg')
                if not os.path.exists(setup_cfg):
                    f = open(setup_cfg, 'w')
                    f.close()
                setuptools.command.setopt.edit_config(
                    setup_cfg, dict(build_ext=build_ext))

                dists = self._call_easy_install(
                    base, pkg_resources.WorkingSet(),
                    self._dest, dist)

                for dist in dists:
                    redo_pyc(dist.location)

                return [dist.location for dist in dists]
            finally:
                shutil.rmtree(build_tmp)

        finally:
            if tmp != self._download_cache:
                shutil.rmtree(tmp)

def default_versions(versions=None):
    old = Installer._versions
    if versions is not None:
        Installer._versions = versions
    return old

def download_cache(path=-1):
    old = Installer._download_cache
    if path != -1:
        if path:
            path = realpath(path)
        Installer._download_cache = path
    return old

def install_from_cache(setting=None):
    old = Installer._install_from_cache
    if setting is not None:
        Installer._install_from_cache = bool(setting)
    return old

def prefer_final(setting=None):
    old = Installer._prefer_final
    if setting is not None:
        Installer._prefer_final = bool(setting)
    return old

def use_dependency_links(setting=None):
    old = Installer._use_dependency_links
    if setting is not None:
        Installer._use_dependency_links = bool(setting)
    return old

def allow_picked_versions(setting=None):
    old = Installer._allow_picked_versions
    if setting is not None:
        Installer._allow_picked_versions = bool(setting)
    return old

def always_unzip(setting=None):
    old = Installer._always_unzip
    if setting is not None:
        Installer._always_unzip = bool(setting)
    return old

def install(specs, dest,
            links=(), index=None,
            executable=sys.executable, always_unzip=None,
            path=None, working_set=None, newest=True, versions=None,
            use_dependency_links=None, allow_hosts=('*',)):
    installer = Installer(dest, links, index, executable, always_unzip, path,
                          newest, versions, use_dependency_links,
                          allow_hosts=allow_hosts)
    return installer.install(specs, working_set)


def build(spec, dest, build_ext,
          links=(), index=None,
          executable=sys.executable,
          path=None, newest=True, versions=None, allow_hosts=('*',)):
    installer = Installer(dest, links, index, executable, True, path, newest,
                          versions, allow_hosts=allow_hosts)
    return installer.build(spec, build_ext)



def _rm(*paths):
    for path in paths:
        if os.path.isdir(path):
            shutil.rmtree(path)
        elif os.path.exists(path):
            os.remove(path)

def _copyeggs(src, dest, suffix, undo):
    result = []
    undo.append(lambda : _rm(*result))
    for name in os.listdir(src):
        if name.endswith(suffix):
            new = os.path.join(dest, name)
            _rm(new)
            os.rename(os.path.join(src, name), new)
            result.append(new)

    assert len(result) == 1, str(result)
    undo.pop()

    return result[0]

def develop(setup, dest,
            build_ext=None,
            executable=sys.executable):

    if os.path.isdir(setup):
        directory = setup
        setup = os.path.join(directory, 'setup.py')
    else:
        directory = os.path.dirname(setup)

    undo = []
    try:
        if build_ext:
            setup_cfg = os.path.join(directory, 'setup.cfg')
            if os.path.exists(setup_cfg):
                os.rename(setup_cfg, setup_cfg+'-develop-aside')
                def restore_old_setup():
                    if os.path.exists(setup_cfg):
                        os.remove(setup_cfg)
                    os.rename(setup_cfg+'-develop-aside', setup_cfg)
                undo.append(restore_old_setup)
            else:
                open(setup_cfg, 'w')
                undo.append(lambda: os.remove(setup_cfg))
            setuptools.command.setopt.edit_config(
                setup_cfg, dict(build_ext=build_ext))

        fd, tsetup = tempfile.mkstemp()
        undo.append(lambda: os.remove(tsetup))
        undo.append(lambda: os.close(fd))

        os.write(fd, runsetup_template % dict(
            setuptools=setuptools_loc,
            setupdir=directory,
            setup=setup,
            __file__ = setup,
            ))

        tmp3 = tempfile.mkdtemp('build', dir=dest)
        undo.append(lambda : shutil.rmtree(tmp3))

        args = [
            zc.buildout.easy_install._safe_arg(tsetup),
            '-q', 'develop', '-mxN',
            '-d', _safe_arg(tmp3),
            ]

        log_level = logger.getEffectiveLevel()
        if log_level <= 0:
            if log_level == 0:
                del args[1]
            else:
                args[1] == '-v'
        if log_level < logging.DEBUG:
            logger.debug("in: %r\n%s", directory, ' '.join(args))

        if is_jython:
            assert subprocess.Popen([_safe_arg(executable)] + args).wait() == 0
        else:
            assert os.spawnl(os.P_WAIT, executable, _safe_arg(executable),
                             *args) == 0

        return _copyeggs(tmp3, dest, '.egg-link', undo)

    finally:
        undo.reverse()
        [f() for f in undo]


def working_set(specs, executable, path):
    return install(specs, None, executable=executable, path=path)

############################################################################
# Script generation functions

def scripts(reqs, working_set, executable, dest,
            scripts=None,
            extra_paths=(),
            arguments='',
            interpreter=None,
            initialization='',
            relative_paths=False,
            ):
    """Generate scripts and/or an interpreter.

    See sitepackage_safe_scripts for a version that can be used with a Python
    that has code installed in site-packages. It has more options and a
    different approach.
    """
    path = _get_path(working_set, extra_paths)
    if initialization:
        initialization = '\n'+initialization+'\n'
    generated = _generate_scripts(
        reqs, working_set, dest, path, scripts, relative_paths,
        initialization, executable, arguments)
    if interpreter:
        sname = os.path.join(dest, interpreter)
        spath, rpsetup = _relative_path_and_setup(sname, path, relative_paths)
        generated.extend(
            _pyscript(spath, sname, executable, rpsetup))
    return generated

def sitepackage_safe_scripts(
    dest, working_set, executable, site_py_dest,
    reqs=(), scripts=None, interpreter=None, extra_paths=(),
    initialization='', add_site_packages=False, exec_sitecustomize=False,
    relative_paths=False, script_arguments='', script_initialization=''):
    """Generate scripts and/or an interpreter from a system Python.

    This accomplishes the same job as the ``scripts`` function, above,
    but it does so in an alternative way that allows safely including
    Python site packages, if desired, and  choosing to execute the Python's
    sitecustomize.
    """
    generated = []
    generated.append(_generate_sitecustomize(
        site_py_dest, executable, initialization, exec_sitecustomize))
    generated.append(_generate_site(
        site_py_dest, working_set, executable, extra_paths,
        add_site_packages, relative_paths))
    script_initialization = (
        '\nimport site # imports custom buildout-generated site.py\n%s' % (
            script_initialization,))
    if not script_initialization.endswith('\n'):
        script_initialization += '\n'
    generated.extend(_generate_scripts(
        reqs, working_set, dest, [site_py_dest], scripts, relative_paths,
        script_initialization, executable, script_arguments, block_site=True))
    if interpreter:
        generated.extend(_generate_interpreter(
            interpreter, dest, executable, site_py_dest, relative_paths))
    return generated

# Utilities for the script generation functions.

# These are shared by both ``scripts`` and ``sitepackage_safe_scripts``

def _get_path(working_set, extra_paths=()):
    """Given working set and extra paths, return a normalized path list."""
    path = [dist.location for dist in working_set]
    path.extend(extra_paths)
    return map(realpath, path)

def _generate_scripts(reqs, working_set, dest, path, scripts, relative_paths,
                      initialization, executable, arguments,
                      block_site=False):
    """Generate scripts for the given requirements.

    - reqs is an iterable of string requirements or entry points.
    - The requirements must be findable in the given working_set.
    - The dest is the directory in which the scripts should be created.
    - The path is a list of paths that should be added to sys.path.
    - The scripts is an optional dictionary.  If included, the keys should be
      the names of the scripts that should be created, as identified in their
      entry points; and the values should be the name the script should
      actually be created with.
    - relative_paths, if given, should be the path that is the root of the
      buildout (the common path that should be the root of what is relative).
    """
    if isinstance(reqs, str):
        raise TypeError('Expected iterable of requirements or entry points,'
                        ' got string.')
    generated = []
    entry_points = []
    for req in reqs:
        if isinstance(req, str):
            req = pkg_resources.Requirement.parse(req)
            dist = working_set.find(req)
            for name in pkg_resources.get_entry_map(dist, 'console_scripts'):
                entry_point = dist.get_entry_info('console_scripts', name)
                entry_points.append(
                    (name, entry_point.module_name,
                     '.'.join(entry_point.attrs))
                    )
        else:
            entry_points.append(req)
    for name, module_name, attrs in entry_points:
        if scripts is not None:
            sname = scripts.get(name)
            if sname is None:
                continue
        else:
            sname = name
        sname = os.path.join(dest, sname)
        spath, rpsetup = _relative_path_and_setup(sname, path, relative_paths)
        generated.extend(
            _script(sname, executable, rpsetup, spath, initialization,
                    module_name, attrs, arguments, block_site=block_site))
    return generated

def _relative_path_and_setup(sname, path,
                             relative_paths=False, indent_level=1,
                             omit_os_import=False):
    """Return a string of code of paths and of setup if appropriate.

    - sname is the full path to the script name to be created.
    - path is the list of paths to be added to sys.path.
    - relative_paths, if given, should be the path that is the root of the
      buildout (the common path that should be the root of what is relative).
    - indent_level is the number of four-space indents that the path should
      insert before each element of the path.
    """
    if relative_paths:
        relative_paths = os.path.normcase(relative_paths)
        sname = os.path.normcase(os.path.abspath(sname))
        spath = _format_paths(
            [_relativitize(os.path.normcase(path_item), sname, relative_paths)
             for path_item in path], indent_level=indent_level)
        rpsetup = relative_paths_setup
        if not omit_os_import:
            rpsetup = '\n\nimport os\n' + rpsetup
        for i in range(_relative_depth(relative_paths, sname)):
            rpsetup += "\nbase = os.path.dirname(base)"
    else:
        spath = _format_paths((repr(p) for p in path),
                              indent_level=indent_level)
        rpsetup = ''
    return spath, rpsetup

def _relative_depth(common, path):
    """Return number of dirs separating ``path`` from ancestor, ``common``.

    For instance, if path is /foo/bar/baz/bing, and common is /foo, this will
    return 2--in UNIX, the number of ".." to get from bing's directory
    to foo.

    This is a helper for _relative_path_and_setup.
    """
    n = 0
    while 1:
        dirname = os.path.dirname(path)
        if dirname == path:
            raise AssertionError("dirname of %s is the same" % dirname)
        if dirname == common:
            break
        n += 1
        path = dirname
    return n

def _relative_path(common, path):
    """Return the relative path from ``common`` to ``path``.

    This is a helper for _relativitize, which is a helper to
    _relative_path_and_setup.
    """
    r = []
    while 1:
        dirname, basename = os.path.split(path)
        r.append(basename)
        if dirname == common:
            break
        if dirname == path:
            raise AssertionError("dirname of %s is the same" % dirname)
        path = dirname
    r.reverse()
    return os.path.join(*r)

def _relativitize(path, script, relative_paths):
    """Return a code string for the given path.

    Path is relative to the base path ``relative_paths``if the common prefix
    between ``path`` and ``script`` starts with ``relative_paths``.
    """
    if path == script:
        raise AssertionError("path == script")
    common = os.path.dirname(os.path.commonprefix([path, script]))
    if (common == relative_paths or
        common.startswith(os.path.join(relative_paths, ''))
        ):
        return "join(base, %r)" % _relative_path(common, path)
    else:
        return repr(path)

relative_paths_setup = """
join = os.path.join
base = os.path.dirname(os.path.abspath(os.path.realpath(__file__)))"""

def _write_script(full_name, contents, logged_type):
    """Write contents of script in full_name, logging the action.

    The only tricky bit in this function is that it supports Windows by
    creating exe files using a pkg_resources helper.
    """
    generated = []
    script_name = full_name
    if is_win32:
        script_name += '-script.py'
        # Generate exe file and give the script a magic name.
        exe = full_name + '.exe'
        new_data = pkg_resources.resource_string('setuptools', 'cli.exe')
        if not os.path.exists(exe) or (open(exe, 'rb').read() != new_data):
            # Only write it if it's different.
            open(exe, 'wb').write(new_data)
        generated.append(exe)
    changed = not (os.path.exists(script_name) and
                   open(script_name).read() == contents)
    if changed:
        open(script_name, 'w').write(contents)
        try:
            os.chmod(script_name, 0755)
        except (AttributeError, os.error):
            pass
        logger.info("Generated %s %r.", logged_type, full_name)
    generated.append(script_name)
    return generated

def _format_paths(paths, indent_level=1):
    """Format paths for inclusion in a script."""
    separator = ',\n' + indent_level * '    '
    return separator.join(paths)

def _script(dest, executable, relative_paths_setup, path, initialization,
            module_name, attrs, arguments, block_site=False):
    if block_site:
        dash_S = ' -S'
    else:
        dash_S = ''
    contents = script_template % dict(
        python=_safe_arg(executable),
        dash_S=dash_S,
        path=path,
        module_name=module_name,
        attrs=attrs,
        arguments=arguments,
        initialization=initialization,
        relative_paths_setup=relative_paths_setup,
        )
    return _write_script(dest, contents, 'script')

if is_jython and jython_os_name == 'linux':
    script_header = '#!/usr/bin/env %(python)s%(dash_S)s'
else:
    script_header = '#!%(python)s%(dash_S)s'

sys_path_template = '''\
import sys
sys.path[0:0] = [
    %s,
    ]
'''

script_template = script_header + '''\
%(relative_paths_setup)s

import sys
sys.path[0:0] = [
    %(path)s,
    ]

%(initialization)s
import %(module_name)s

if __name__ == '__main__':
    %(module_name)s.%(attrs)s(%(arguments)s)
'''

# These are used only by the older ``scripts`` function.

def _pyscript(path, dest, executable, rsetup):
    contents = py_script_template % dict(
        python=_safe_arg(executable),
        dash_S='',
        path=path,
        relative_paths_setup=rsetup,
        )
    return _write_script(dest, contents, 'interpreter')

py_script_template = script_header + '''\
%(relative_paths_setup)s

import sys

sys.path[0:0] = [
    %(path)s,
    ]

_interactive = True
if len(sys.argv) > 1:
    _options, _args = __import__("getopt").getopt(sys.argv[1:], 'ic:m:')
    _interactive = False
    for (_opt, _val) in _options:
        if _opt == '-i':
            _interactive = True
        elif _opt == '-c':
            exec _val
        elif _opt == '-m':
            sys.argv[1:] = _args
            _args = []
            __import__("runpy").run_module(
                 _val, {}, "__main__", alter_sys=True)

    if _args:
        sys.argv[:] = _args
        __file__ = _args[0]
        del _options, _args
        execfile(__file__)

if _interactive:
    del _interactive
    __import__("code").interact(banner="", local=globals())
'''

# These are used only by the newer ``sitepackage_safe_scripts`` function.

def _get_system_paths(executable):
    """Return lists of standard lib and site paths for executable.
    """
    # We want to get a list of the site packages, which is not easy.
    # The canonical way to do this is to use
    # distutils.sysconfig.get_python_lib(), but that only returns a
    # single path, which does not reflect reality for many system
    # Pythons, which have multiple additions.  Instead, we start Python
    # with -S, which does not import site.py and set up the extra paths
    # like site-packages or (Ubuntu/Debian) dist-packages and
    # python-support. We then compare that sys.path with the normal one
    # (minus user packages if this is Python 2.6, because we don't
    # support those (yet?).  The set of the normal one minus the set of
    # the ones in ``python -S`` is the set of packages that are
    # effectively site-packages.
    #
    # The given executable might not be the current executable, so it is
    # appropriate to do another subprocess to figure out what the
    # additional site-package paths are. Moreover, even if this
    # executable *is* the current executable, this code might be run in
    # the context of code that has manipulated the sys.path--for
    # instance, to add local zc.buildout or setuptools eggs.
    def get_sys_path(*args, **kwargs):
        cmd = [executable]
        cmd.extend(args)
        cmd.extend([
            "-c", "import sys, os;"
            "print repr([os.path.normpath(p) for p in sys.path if p])"])
        # Windows needs some (as yet to be determined) part of the real env.
        env = os.environ.copy()
        env.update(kwargs)
        _proc = subprocess.Popen(
            cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=env)
        stdout, stderr = _proc.communicate();
        if _proc.returncode:
            raise RuntimeError(
                'error trying to get system packages:\n%s' % (stderr,))
        res = eval(stdout.strip())
        try:
            res.remove('.')
        except ValueError:
            pass
        return res
    stdlib = get_sys_path('-S') # stdlib only
    no_user_paths = get_sys_path(PYTHONNOUSERSITE='x')
    site_paths = [p for p in no_user_paths if p not in stdlib]
    return (stdlib, site_paths)

def _get_module_file(executable, name):
    """Return a module's file path.

    - executable is a path to the desired Python executable.
    - name is the name of the (pure, not C) Python module.
    """
    cmd = [executable, "-c",
           "import imp; "
           "fp, path, desc = imp.find_module(%r); "
           "fp.close; "
           "print path" % (name,)]
    _proc = subprocess.Popen(
        cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    stdout, stderr = _proc.communicate();
    if _proc.returncode:
        logger.info(
            'Could not find file for module %s:\n%s', name, stderr)
        return None
    # else: ...
    res = stdout.strip()
    if res.endswith('.pyc') or res.endswith('.pyo'):
        raise RuntimeError('Cannot find uncompiled version of %s' % (name,))
    if not os.path.exists(res):
        raise RuntimeError(
            'File does not exist for module %s:\n%s' % (name, res))
    return res

def _generate_sitecustomize(dest, executable, initialization='',
                            exec_sitecustomize=False):
    """Write a sitecustomize file with optional custom initialization.

    The created script will execute the underlying Python's
    sitecustomize if exec_sitecustomize is True.
    """
    sitecustomize_path = os.path.join(dest, 'sitecustomize.py')
    sitecustomize = open(sitecustomize_path, 'w')
    if initialization:
        sitecustomize.write(initialization + '\n')
    if exec_sitecustomize:
        real_sitecustomize_path = _get_module_file(
            executable, 'sitecustomize')
        if real_sitecustomize_path:
            real_sitecustomize = open(real_sitecustomize_path, 'r')
            sitecustomize.write(
                '\n# The following is from\n# %s\n' %
                (real_sitecustomize_path,))
            sitecustomize.write(real_sitecustomize.read())
            real_sitecustomize.close()
    sitecustomize.close()
    return sitecustomize_path

def _generate_site(dest, working_set, executable, extra_paths=(),
                   add_site_packages=False, relative_paths=False):
    """Write a site.py file with eggs from working_set.

    extra_paths will be added to the path.  If add_site_packages is True,
    paths from the underlying Python will be added.
    """
    path = _get_path(working_set, extra_paths)
    site_path = os.path.join(dest, 'site.py')
    egg_path_string, preamble = _relative_path_and_setup(
        site_path, path, relative_paths, indent_level=2, omit_os_import=True)
    if preamble:
        preamble = '\n'.join(
            [(line and '    %s' % (line,) or line)
             for line in preamble.split('\n')])
    original_path_setup = ''
    if add_site_packages:
        stdlib, site_paths = _get_system_paths(executable)
        original_path_setup = original_path_snippet % (
            _format_paths((repr(p) for p in site_paths), 2),)
        distribution = working_set.find(
            pkg_resources.Requirement.parse('setuptools'))
        if distribution is not None:
            # We need to worry about namespace packages.
            if relative_paths:
                location = _relativitize(
                    distribution.location,
                    os.path.normcase(os.path.abspath(site_path)),
                    relative_paths)
            else:
                location = repr(distribution.location)
            preamble += namespace_add_site_packages_setup % (location,)
            original_path_setup = (
                addsitedir_namespace_originalpackages_snippet +
                original_path_setup)
    addsitepackages_marker = 'def addsitepackages('
    enableusersite_marker = 'ENABLE_USER_SITE = '
    successful_rewrite = False
    real_site_path = _get_module_file(executable, 'site')
    real_site = open(real_site_path, 'r')
    site = open(site_path, 'w')
    try:
        for line in real_site.readlines():
            if line.startswith(enableusersite_marker):
                site.write(enableusersite_marker)
                site.write('False # buildout does not support user sites.\n')
            elif line.startswith(addsitepackages_marker):
                site.write(addsitepackages_script % (
                    preamble, egg_path_string, original_path_setup))
                site.write(line[len(addsitepackages_marker):])
                successful_rewrite = True
            else:
                site.write(line)
    finally:
        site.close()
        real_site.close()
    if not successful_rewrite:
        raise RuntimeError('Buildout did not successfully rewrite site.py')
    return site_path

namespace_add_site_packages_setup = '''
    setuptools_path = %s
    sys.path.append(setuptools_path)
    known_paths.add(os.path.normcase(setuptools_path))
    import pkg_resources'''

addsitedir_namespace_originalpackages_snippet = '''
            pkg_resources.working_set.add_entry(sitedir)'''

original_path_snippet = '''
    original_paths = [
        %s
        ]
    for path in original_paths:
        addsitedir(path, known_paths)'''

addsitepackages_script = '''\
def addsitepackages(known_paths):
    """Add site packages, as determined by zc.buildout.

    See original_addsitepackages, below, for the original version."""%s
    buildout_paths = [
        %s
        ]
    for path in buildout_paths:
        sitedir, sitedircase = makepath(path)
        if not sitedircase in known_paths and os.path.exists(sitedir):
            sys.path.append(sitedir)
            known_paths.add(sitedircase)%s
    return known_paths

def original_addsitepackages('''

def _generate_interpreter(name, dest, executable, site_py_dest,
                          relative_paths=False):
    """Write an interpreter script, using the site.py approach."""
    full_name = os.path.join(dest, name)
    site_py_dest_string, rpsetup = _relative_path_and_setup(
        full_name, [site_py_dest], relative_paths, omit_os_import=True)
    if rpsetup:
        rpsetup += "\n"
    if sys.platform == 'win32':
        windows_import = '\nimport subprocess'
        # os.exec* is a mess on Windows, particularly if the path
        # to the executable has spaces and the Python is using MSVCRT.
        # The standard fix is to surround the executable's path with quotes,
        # but that has been unreliable in testing.
        #
        # Here's a demonstration of the problem.  Given a Python
        # compiled with a MSVCRT-based compiler, such as the free Visual
        # C++ 2008 Express Edition, and an executable path with spaces
        # in it such as the below, we see the following.
        #
        # >>> import os
        # >>> p0 = 'C:\\Documents and Settings\\Administrator\\My Documents\\Downloads\\Python-2.6.4\\PCbuild\\python.exe'
        # >>> os.path.exists(p0)
        # True
        # >>> os.execv(p0, [])
        # Traceback (most recent call last):
        #  File "<stdin>", line 1, in <module>
        # OSError: [Errno 22] Invalid argument
        #
        # That seems like a standard problem.  The standard solution is
        # to quote the path (see, for instance
        # http://bugs.python.org/issue436259).  However, this solution,
        # and other variations, fail:
        #
        # >>> p1 = '"C:\\Documents and Settings\\Administrator\\My Documents\\Downloads\\Python-2.6.4\\PCbuild\\python.exe"'
        # >>> os.execv(p1, [])
        # Traceback (most recent call last):
        #   File "<stdin>", line 1, in <module>
        # OSError: [Errno 22] Invalid argument
        #
        # We simply use subprocess instead, since it handles everything
        # nicely, and the transparency of exec* (that is, not running,
        # perhaps unexpectedly, in a subprocess) is arguably not a
        # necessity, at least for many use cases.
        execute = 'subprocess.call(argv, env=environ)'
    else:
        windows_import = ''
        execute = 'os.execve(sys.executable, argv, environ)'
    contents = interpreter_template % dict(
        python=_safe_arg(executable),
        dash_S=' -S',
        site_dest=site_py_dest_string,
        relative_paths_setup=rpsetup,
        windows_import=windows_import,
        execute=execute,
        )
    return _write_script(full_name, contents, 'interpreter')

interpreter_template = script_header + '''
import os
import sys%(windows_import)s
%(relative_paths_setup)s
argv = [sys.executable] + sys.argv[1:]
environ = os.environ.copy()
path = %(site_dest)s
if environ.get('PYTHONPATH'):
    path = os.pathsep.join([path, environ['PYTHONPATH']])
environ['PYTHONPATH'] = path
%(execute)s
'''

# End of script generation code.
############################################################################

runsetup_template = """
import sys
sys.path.insert(0, %(setupdir)r)
sys.path.insert(0, %(setuptools)r)
import os, setuptools

__file__ = %(__file__)r

os.chdir(%(setupdir)r)
sys.argv[0] = %(setup)r
execfile(%(setup)r)
"""


class VersionConflict(zc.buildout.UserError):

    def __init__(self, err, ws):
        ws = list(ws)
        ws.sort()
        self.err, self.ws = err, ws

    def __str__(self):
        existing_dist, req = self.err
        result = ["There is a version conflict.",
                  "We already have: %s" % existing_dist,
                  ]
        for dist in self.ws:
            if req in dist.requires():
                result.append("but %s requires %r." % (dist, str(req)))
        return '\n'.join(result)


class MissingDistribution(zc.buildout.UserError):

    def __init__(self, req, ws):
        ws = list(ws)
        ws.sort()
        self.data = req, ws

    def __str__(self):
        req, ws = self.data
        return "Couldn't find a distribution for %r." % str(req)

def _log_requirement(ws, req):
    ws = list(ws)
    ws.sort()
    for dist in ws:
        if req in dist.requires():
            logger.debug("  required by %s." % dist)

def _fix_file_links(links):
    for link in links:
        if link.startswith('file://') and link[-1] != '/':
            if os.path.isdir(link[7:]):
                # work around excessive restriction in setuptools:
                link += '/'
        yield link

_final_parts = '*final-', '*final'
def _final_version(parsed_version):
    for part in parsed_version:
        if (part[:1] == '*') and (part not in _final_parts):
            return False
    return True

def redo_pyc(egg):
    if not os.path.isdir(egg):
        return
    for dirpath, dirnames, filenames in os.walk(egg):
        for filename in filenames:
            if not filename.endswith('.py'):
                continue
            filepath = os.path.join(dirpath, filename)
            if not (os.path.exists(filepath+'c')
                    or os.path.exists(filepath+'o')):
                # If it wasn't compiled, it may not be compilable
                continue

            # OK, it looks like we should try to compile.

            # Remove old files.
            for suffix in 'co':
                if os.path.exists(filepath+suffix):
                    os.remove(filepath+suffix)

            # Compile under current optimization
            try:
                py_compile.compile(filepath)
            except py_compile.PyCompileError:
                logger.warning("Couldn't compile %s", filepath)
            else:
                # Recompile under other optimization. :)
                args = [_safe_arg(sys.executable)]
                if __debug__:
                    args.append('-O')
                args.extend(['-m', 'py_compile', _safe_arg(filepath)])

                if is_jython:
                    subprocess.call([sys.executable, args])
                else:
                    os.spawnv(os.P_WAIT, sys.executable, args)