This file is indexed.

/usr/lib/python3/dist-packages/Cython/Build/Dependencies.py is in cython3 0.25.2-1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

   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
from __future__ import absolute_import, print_function

import cython
from .. import __version__

import collections
import re, os, sys, time
from glob import iglob

try:
    import gzip
    gzip_open = gzip.open
    gzip_ext = '.gz'
except ImportError:
    gzip_open = open
    gzip_ext = ''
import shutil
import subprocess

try:
    import hashlib
except ImportError:
    import md5 as hashlib

try:
    from io import open as io_open
except ImportError:
    from codecs import open as io_open

try:
    from os.path import relpath as _relpath
except ImportError:
    # Py<2.6
    def _relpath(path, start=os.path.curdir):
        if not path:
            raise ValueError("no path specified")
        start_list = os.path.abspath(start).split(os.path.sep)
        path_list = os.path.abspath(path).split(os.path.sep)
        i = len(os.path.commonprefix([start_list, path_list]))
        rel_list = [os.path.pardir] * (len(start_list)-i) + path_list[i:]
        if not rel_list:
            return os.path.curdir
        return os.path.join(*rel_list)


from distutils.extension import Extension

from .. import Utils
from ..Utils import (cached_function, cached_method, path_exists,
    safe_makedirs, copy_file_to_dir_if_newer, is_package_dir)
from ..Compiler.Main import Context, CompilationOptions, default_options

join_path = cached_function(os.path.join)
copy_once_if_newer = cached_function(copy_file_to_dir_if_newer)
safe_makedirs_once = cached_function(safe_makedirs)

if sys.version_info[0] < 3:
    # stupid Py2 distutils enforces str type in list of sources
    _fs_encoding = sys.getfilesystemencoding()
    if _fs_encoding is None:
        _fs_encoding = sys.getdefaultencoding()
    def encode_filename_in_py2(filename):
        if not isinstance(filename, bytes):
            return filename.encode(_fs_encoding)
        return filename
else:
    def encode_filename_in_py2(filename):
        return filename
    basestring = str


def extended_iglob(pattern):
    if '{' in pattern:
        m = re.match('(.*){([^}]+)}(.*)', pattern)
        if m:
            before, switch, after = m.groups()
            for case in switch.split(','):
                for path in extended_iglob(before + case + after):
                    yield path
            return
    if '**/' in pattern:
        seen = set()
        first, rest = pattern.split('**/', 1)
        if first:
            first = iglob(first+'/')
        else:
            first = ['']
        for root in first:
            for path in extended_iglob(join_path(root, rest)):
                if path not in seen:
                    seen.add(path)
                    yield path
            for path in extended_iglob(join_path(root, '*', '**/' + rest)):
                if path not in seen:
                    seen.add(path)
                    yield path
    else:
        for path in iglob(pattern):
            yield path


def nonempty(it, error_msg="expected non-empty iterator"):
    empty = True
    for value in it:
        empty = False
        yield value
    if empty:
        raise ValueError(error_msg)


@cached_function
def file_hash(filename):
    path = os.path.normpath(filename.encode("UTF-8"))
    m = hashlib.md5(str(len(path)) + ":")
    m.update(path)
    f = open(filename, 'rb')
    try:
        data = f.read(65000)
        while data:
            m.update(data)
            data = f.read(65000)
    finally:
        f.close()
    return m.hexdigest()


def parse_list(s):
    """
    >>> parse_list("")
    []
    >>> parse_list("a")
    ['a']
    >>> parse_list("a b c")
    ['a', 'b', 'c']
    >>> parse_list("[a, b, c]")
    ['a', 'b', 'c']
    >>> parse_list('a " " b')
    ['a', ' ', 'b']
    >>> parse_list('[a, ",a", "a,", ",", ]')
    ['a', ',a', 'a,', ',']
    """
    if len(s) >= 2 and s[0] == '[' and s[-1] == ']':
        s = s[1:-1]
        delimiter = ','
    else:
        delimiter = ' '
    s, literals = strip_string_literals(s)
    def unquote(literal):
        literal = literal.strip()
        if literal[0] in "'\"":
            return literals[literal[1:-1]]
        else:
            return literal
    return [unquote(item) for item in s.split(delimiter) if item.strip()]


transitive_str = object()
transitive_list = object()

distutils_settings = {
    'name':                 str,
    'sources':              list,
    'define_macros':        list,
    'undef_macros':         list,
    'libraries':            transitive_list,
    'library_dirs':         transitive_list,
    'runtime_library_dirs': transitive_list,
    'include_dirs':         transitive_list,
    'extra_objects':        list,
    'extra_compile_args':   transitive_list,
    'extra_link_args':      transitive_list,
    'export_symbols':       list,
    'depends':              transitive_list,
    'language':             transitive_str,
}


@cython.locals(start=cython.Py_ssize_t, end=cython.Py_ssize_t)
def line_iter(source):
    if isinstance(source, basestring):
        start = 0
        while True:
            end = source.find('\n', start)
            if end == -1:
                yield source[start:]
                return
            yield source[start:end]
            start = end+1
    else:
        for line in source:
            yield line


class DistutilsInfo(object):

    def __init__(self, source=None, exn=None):
        self.values = {}
        if source is not None:
            for line in line_iter(source):
                line = line.lstrip()
                if not line:
                    continue
                if line[0] != '#':
                    break
                line = line[1:].lstrip()
                if line[:10] == 'distutils:':
                    key, _, value = [s.strip() for s in line[10:].partition('=')]
                    type = distutils_settings[key]
                    if type in (list, transitive_list):
                        value = parse_list(value)
                        if key == 'define_macros':
                            value = [tuple(macro.split('=', 1))
                                     if '=' in macro else (macro, None)
                                     for macro in value]
                    self.values[key] = value
        elif exn is not None:
            for key in distutils_settings:
                if key in ('name', 'sources'):
                    continue
                value = getattr(exn, key, None)
                if value:
                    self.values[key] = value

    def merge(self, other):
        if other is None:
            return self
        for key, value in other.values.items():
            type = distutils_settings[key]
            if type is transitive_str and key not in self.values:
                self.values[key] = value
            elif type is transitive_list:
                if key in self.values:
                    # Change a *copy* of the list (Trac #845)
                    all = self.values[key][:]
                    for v in value:
                        if v not in all:
                            all.append(v)
                    value = all
                self.values[key] = value
        return self

    def subs(self, aliases):
        if aliases is None:
            return self
        resolved = DistutilsInfo()
        for key, value in self.values.items():
            type = distutils_settings[key]
            if type in [list, transitive_list]:
                new_value_list = []
                for v in value:
                    if v in aliases:
                        v = aliases[v]
                    if isinstance(v, list):
                        new_value_list += v
                    else:
                        new_value_list.append(v)
                value = new_value_list
            else:
                if value in aliases:
                    value = aliases[value]
            resolved.values[key] = value
        return resolved

    def apply(self, extension):
        for key, value in self.values.items():
            type = distutils_settings[key]
            if type in [list, transitive_list]:
                value = getattr(extension, key) + list(value)
            setattr(extension, key, value)


@cython.locals(start=cython.Py_ssize_t, q=cython.Py_ssize_t,
               single_q=cython.Py_ssize_t, double_q=cython.Py_ssize_t,
               hash_mark=cython.Py_ssize_t, end=cython.Py_ssize_t,
               k=cython.Py_ssize_t, counter=cython.Py_ssize_t, quote_len=cython.Py_ssize_t)
def strip_string_literals(code, prefix='__Pyx_L'):
    """
    Normalizes every string literal to be of the form '__Pyx_Lxxx',
    returning the normalized code and a mapping of labels to
    string literals.
    """
    new_code = []
    literals = {}
    counter = 0
    start = q = 0
    in_quote = False
    hash_mark = single_q = double_q = -1
    code_len = len(code)
    quote_type = quote_len = None

    while True:
        if hash_mark < q:
            hash_mark = code.find('#', q)
        if single_q < q:
            single_q = code.find("'", q)
        if double_q < q:
            double_q = code.find('"', q)
        q = min(single_q, double_q)
        if q == -1:
            q = max(single_q, double_q)

        # We're done.
        if q == -1 and hash_mark == -1:
            new_code.append(code[start:])
            break

        # Try to close the quote.
        elif in_quote:
            if code[q-1] == u'\\':
                k = 2
                while q >= k and code[q-k] == u'\\':
                    k += 1
                if k % 2 == 0:
                    q += 1
                    continue
            if code[q] == quote_type and (
                    quote_len == 1 or (code_len > q + 2 and quote_type == code[q+1] == code[q+2])):
                counter += 1
                label = "%s%s_" % (prefix, counter)
                literals[label] = code[start+quote_len:q]
                full_quote = code[q:q+quote_len]
                new_code.append(full_quote)
                new_code.append(label)
                new_code.append(full_quote)
                q += quote_len
                in_quote = False
                start = q
            else:
                q += 1

        # Process comment.
        elif -1 != hash_mark and (hash_mark < q or q == -1):
            new_code.append(code[start:hash_mark+1])
            end = code.find('\n', hash_mark)
            counter += 1
            label = "%s%s_" % (prefix, counter)
            if end == -1:
                end_or_none = None
            else:
                end_or_none = end
            literals[label] = code[hash_mark+1:end_or_none]
            new_code.append(label)
            if end == -1:
                break
            start = q = end

        # Open the quote.
        else:
            if code_len >= q+3 and (code[q] == code[q+1] == code[q+2]):
                quote_len = 3
            else:
                quote_len = 1
            in_quote = True
            quote_type = code[q]
            new_code.append(code[start:q])
            start = q
            q += quote_len

    return "".join(new_code), literals


# We need to allow spaces to allow for conditional compilation like
# IF ...:
#     cimport ...
dependency_regex = re.compile(r"(?:^\s*from +([0-9a-zA-Z_.]+) +cimport)|"
                              r"(?:^\s*cimport +([0-9a-zA-Z_.]+(?: *, *[0-9a-zA-Z_.]+)*))|"
                              r"(?:^\s*cdef +extern +from +['\"]([^'\"]+)['\"])|"
                              r"(?:^\s*include +['\"]([^'\"]+)['\"])", re.M)


def normalize_existing(base_path, rel_paths):
    return normalize_existing0(os.path.dirname(base_path), tuple(set(rel_paths)))


@cached_function
def normalize_existing0(base_dir, rel_paths):
    normalized = []
    for rel in rel_paths:
        path = join_path(base_dir, rel)
        if path_exists(path):
            normalized.append(os.path.normpath(path))
        else:
            normalized.append(rel)
    return normalized


def resolve_depends(depends, include_dirs):
    include_dirs = tuple(include_dirs)
    resolved = []
    for depend in depends:
        path = resolve_depend(depend, include_dirs)
        if path is not None:
            resolved.append(path)
    return resolved


@cached_function
def resolve_depend(depend, include_dirs):
    if depend[0] == '<' and depend[-1] == '>':
        return None
    for dir in include_dirs:
        path = join_path(dir, depend)
        if path_exists(path):
            return os.path.normpath(path)
    return None


@cached_function
def package(filename):
    dir = os.path.dirname(os.path.abspath(str(filename)))
    if dir != filename and is_package_dir(dir):
        return package(dir) + (os.path.basename(dir),)
    else:
        return ()


@cached_function
def fully_qualified_name(filename):
    module = os.path.splitext(os.path.basename(filename))[0]
    return '.'.join(package(filename) + (module,))


@cached_function
def parse_dependencies(source_filename):
    # Actual parsing is way too slow, so we use regular expressions.
    # The only catch is that we must strip comments and string
    # literals ahead of time.
    fh = Utils.open_source_file(source_filename, error_handling='ignore')
    try:
        source = fh.read()
    finally:
        fh.close()
    distutils_info = DistutilsInfo(source)
    source, literals = strip_string_literals(source)
    source = source.replace('\\\n', ' ').replace('\t', ' ')

    # TODO: pure mode
    cimports = []
    includes = []
    externs  = []
    for m in dependency_regex.finditer(source):
        cimport_from, cimport_list, extern, include = m.groups()
        if cimport_from:
            cimports.append(cimport_from)
        elif cimport_list:
            cimports.extend(x.strip() for x in cimport_list.split(","))
        elif extern:
            externs.append(literals[extern])
        else:
            includes.append(literals[include])
    return cimports, includes, externs, distutils_info


class DependencyTree(object):

    def __init__(self, context, quiet=False):
        self.context = context
        self.quiet = quiet
        self._transitive_cache = {}

    def parse_dependencies(self, source_filename):
        if path_exists(source_filename):
            source_filename = os.path.normpath(source_filename)
        return parse_dependencies(source_filename)

    @cached_method
    def included_files(self, filename):
        # This is messy because included files are textually included, resolving
        # cimports (but not includes) relative to the including file.
        all = set()
        for include in self.parse_dependencies(filename)[1]:
            include_path = join_path(os.path.dirname(filename), include)
            if not path_exists(include_path):
                include_path = self.context.find_include_file(include, None)
            if include_path:
                if '.' + os.path.sep in include_path:
                    include_path = os.path.normpath(include_path)
                all.add(include_path)
                all.update(self.included_files(include_path))
            elif not self.quiet:
                print("Unable to locate '%s' referenced from '%s'" % (filename, include))
        return all

    @cached_method
    def cimports_and_externs(self, filename):
        # This is really ugly. Nested cimports are resolved with respect to the
        # includer, but includes are resolved with respect to the includee.
        cimports, includes, externs = self.parse_dependencies(filename)[:3]
        cimports = set(cimports)
        externs = set(externs)
        for include in self.included_files(filename):
            included_cimports, included_externs = self.cimports_and_externs(include)
            cimports.update(included_cimports)
            externs.update(included_externs)
        return tuple(cimports), normalize_existing(filename, externs)

    def cimports(self, filename):
        return self.cimports_and_externs(filename)[0]

    def package(self, filename):
        return package(filename)

    def fully_qualified_name(self, filename):
        return fully_qualified_name(filename)

    @cached_method
    def find_pxd(self, module, filename=None):
        is_relative = module[0] == '.'
        if is_relative and not filename:
            raise NotImplementedError("New relative imports.")
        if filename is not None:
            module_path = module.split('.')
            if is_relative:
                module_path.pop(0)  # just explicitly relative
            package_path = list(self.package(filename))
            while module_path and not module_path[0]:
                try:
                    package_path.pop()
                except IndexError:
                    return None   # FIXME: error?
                module_path.pop(0)
            relative = '.'.join(package_path + module_path)
            pxd = self.context.find_pxd_file(relative, None)
            if pxd:
                return pxd
        if is_relative:
            return None   # FIXME: error?
        return self.context.find_pxd_file(module, None)

    @cached_method
    def cimported_files(self, filename):
        if filename[-4:] == '.pyx' and path_exists(filename[:-4] + '.pxd'):
            pxd_list = [filename[:-4] + '.pxd']
        else:
            pxd_list = []
        for module in self.cimports(filename):
            if module[:7] == 'cython.' or module == 'cython':
                continue
            pxd_file = self.find_pxd(module, filename)
            if pxd_file is not None:
                pxd_list.append(pxd_file)
            elif not self.quiet:
                print("%s: cannot find cimported module '%s'" % (filename, module))
        return tuple(pxd_list)

    @cached_method
    def immediate_dependencies(self, filename):
        all = set([filename])
        all.update(self.cimported_files(filename))
        all.update(self.included_files(filename))
        return all

    def all_dependencies(self, filename):
        return self.transitive_merge(filename, self.immediate_dependencies, set.union)

    @cached_method
    def timestamp(self, filename):
        return os.path.getmtime(filename)

    def extract_timestamp(self, filename):
        return self.timestamp(filename), filename

    def newest_dependency(self, filename):
        return max([self.extract_timestamp(f) for f in self.all_dependencies(filename)])

    def transitive_fingerprint(self, filename, extra=None):
        try:
            m = hashlib.md5(__version__)
            m.update(file_hash(filename))
            for x in sorted(self.all_dependencies(filename)):
                if os.path.splitext(x)[1] not in ('.c', '.cpp', '.h'):
                    m.update(file_hash(x))
            if extra is not None:
                m.update(str(extra))
            return m.hexdigest()
        except IOError:
            return None

    def distutils_info0(self, filename):
        info = self.parse_dependencies(filename)[3]
        externs = self.cimports_and_externs(filename)[1]
        if externs:
            if 'depends' in info.values:
                info.values['depends'] = list(set(info.values['depends']).union(externs))
            else:
                info.values['depends'] = list(externs)
        return info

    def distutils_info(self, filename, aliases=None, base=None):
        return (self.transitive_merge(filename, self.distutils_info0, DistutilsInfo.merge)
            .subs(aliases)
            .merge(base))

    def transitive_merge(self, node, extract, merge):
        try:
            seen = self._transitive_cache[extract, merge]
        except KeyError:
            seen = self._transitive_cache[extract, merge] = {}
        return self.transitive_merge_helper(
            node, extract, merge, seen, {}, self.cimported_files)[0]

    def transitive_merge_helper(self, node, extract, merge, seen, stack, outgoing):
        if node in seen:
            return seen[node], None
        deps = extract(node)
        if node in stack:
            return deps, node
        try:
            stack[node] = len(stack)
            loop = None
            for next in outgoing(node):
                sub_deps, sub_loop = self.transitive_merge_helper(next, extract, merge, seen, stack, outgoing)
                if sub_loop is not None:
                    if loop is not None and stack[loop] < stack[sub_loop]:
                        pass
                    else:
                        loop = sub_loop
                deps = merge(deps, sub_deps)
            if loop == node:
                loop = None
            if loop is None:
                seen[node] = deps
            return deps, loop
        finally:
            del stack[node]


_dep_tree = None

def create_dependency_tree(ctx=None, quiet=False):
    global _dep_tree
    if _dep_tree is None:
        if ctx is None:
            ctx = Context(["."], CompilationOptions(default_options))
        _dep_tree = DependencyTree(ctx, quiet=quiet)
    return _dep_tree


# This may be useful for advanced users?
def create_extension_list(patterns, exclude=None, ctx=None, aliases=None, quiet=False, language=None,
                          exclude_failures=False):
    if language is not None:
        print('Please put "# distutils: language=%s" in your .pyx or .pxd file(s)' % language)
    if exclude is None:
        exclude = []
    if patterns is None:
        return [], {}
    elif isinstance(patterns, basestring) or not isinstance(patterns, collections.Iterable):
        patterns = [patterns]
    explicit_modules = set([m.name for m in patterns if isinstance(m, Extension)])
    seen = set()
    deps = create_dependency_tree(ctx, quiet=quiet)
    to_exclude = set()
    if not isinstance(exclude, list):
        exclude = [exclude]
    for pattern in exclude:
        to_exclude.update(map(os.path.abspath, extended_iglob(pattern)))

    module_list = []
    module_metadata = {}

    # workaround for setuptools
    if 'setuptools' in sys.modules:
        Extension_distutils = sys.modules['setuptools.extension']._Extension
        Extension_setuptools = sys.modules['setuptools'].Extension
    else:
        # dummy class, in case we do not have setuptools
        Extension_distutils = Extension
        class Extension_setuptools(Extension): pass

    for pattern in patterns:
        if isinstance(pattern, str):
            filepattern = pattern
            template = None
            name = '*'
            base = None
            exn_type = Extension
            ext_language = language
        elif isinstance(pattern, (Extension_distutils, Extension_setuptools)):
            cython_sources = [s for s in pattern.sources
                              if os.path.splitext(s)[1] in ('.py', '.pyx')]
            if cython_sources:
              filepattern = cython_sources[0]
              if len(cython_sources) > 1:
                print("Warning: Multiple cython sources found for extension '%s': %s\n"
                "See http://cython.readthedocs.io/en/latest/src/userguide/sharing_declarations.html "
                "for sharing declarations among Cython files." % (pattern.name, cython_sources))
            else:
                # ignore non-cython modules
                module_list.append(pattern)
                continue
            template = pattern
            name = template.name
            base = DistutilsInfo(exn=template)
            exn_type = template.__class__
            ext_language = None  # do not override whatever the Extension says
        else:
            msg = str("pattern is not of type str nor subclass of Extension (%s)"
                      " but of type %s and class %s" % (repr(Extension),
                                                        type(pattern),
                                                        pattern.__class__))
            raise TypeError(msg)

        for file in nonempty(sorted(extended_iglob(filepattern)), "'%s' doesn't match any files" % filepattern):
            if os.path.abspath(file) in to_exclude:
                continue
            pkg = deps.package(file)
            module_name = deps.fully_qualified_name(file)
            if '*' in name:
                if module_name in explicit_modules:
                    continue
            elif name != module_name:
                print("Warning: Extension name '%s' does not match fully qualified name '%s' of '%s'" % (
                    name, module_name, file))
                module_name = name

            if module_name not in seen:
                try:
                    kwds = deps.distutils_info(file, aliases, base).values
                except Exception:
                    if exclude_failures:
                        continue
                    raise
                if base is not None:
                    for key, value in base.values.items():
                        if key not in kwds:
                            kwds[key] = value

                sources = [file]
                if template is not None:
                    sources += [m for m in template.sources if m != filepattern]
                if 'sources' in kwds:
                    # allow users to add .c files etc.
                    for source in kwds['sources']:
                        source = encode_filename_in_py2(source)
                        if source not in sources:
                            sources.append(source)
                    extra_sources = kwds['sources']
                    del kwds['sources']
                else:
                    extra_sources = None
                if 'depends' in kwds:
                    depends = resolve_depends(kwds['depends'], (kwds.get('include_dirs') or []) + ["."])
                    if template is not None:
                        # Always include everything from the template.
                        depends = set(template.depends).union(depends)
                    # Sort depends to make the metadata dump in the
                    # Cython-generated C code predictable.
                    kwds['depends'] = sorted(depends)

                if ext_language and 'language' not in kwds:
                    kwds['language'] = ext_language

                module_list.append(exn_type(
                        name=module_name,
                        sources=sources,
                        **kwds))
                if extra_sources:
                    kwds['sources'] = extra_sources
                module_metadata[module_name] = {'distutils': kwds, 'module_name': module_name}
                m = module_list[-1]
                if file not in m.sources:
                    # Old setuptools unconditionally replaces .pyx with .c
                    m.sources.remove(file.rsplit('.')[0] + '.c')
                    m.sources.insert(0, file)
                seen.add(name)
    return module_list, module_metadata


# This is the user-exposed entry point.
def cythonize(module_list, exclude=None, nthreads=0, aliases=None, quiet=False, force=False, language=None,
              exclude_failures=False, **options):
    """
    Compile a set of source modules into C/C++ files and return a list of distutils
    Extension objects for them.

    As module list, pass either a glob pattern, a list of glob patterns or a list of
    Extension objects.  The latter allows you to configure the extensions separately
    through the normal distutils options.

    When using glob patterns, you can exclude certain module names explicitly
    by passing them into the 'exclude' option.

    To globally enable C++ mode, you can pass language='c++'.  Otherwise, this
    will be determined at a per-file level based on compiler directives.  This
    affects only modules found based on file names.  Extension instances passed
    into cythonize() will not be changed.

    For parallel compilation, set the 'nthreads' option to the number of
    concurrent builds.

    For a broad 'try to compile' mode that ignores compilation failures and
    simply excludes the failed extensions, pass 'exclude_failures=True'. Note
    that this only really makes sense for compiling .py files which can also
    be used without compilation.

    Additional compilation options can be passed as keyword arguments.
    """
    if exclude is None:
        exclude = []
    if 'include_path' not in options:
        options['include_path'] = ['.']
    if 'common_utility_include_dir' in options:
        if options.get('cache'):
            raise NotImplementedError("common_utility_include_dir does not yet work with caching")
        safe_makedirs(options['common_utility_include_dir'])
    c_options = CompilationOptions(**options)
    cpp_options = CompilationOptions(**options); cpp_options.cplus = True
    ctx = c_options.create_context()
    options = c_options
    module_list, module_metadata = create_extension_list(
        module_list,
        exclude=exclude,
        ctx=ctx,
        quiet=quiet,
        exclude_failures=exclude_failures,
        language=language,
        aliases=aliases)
    deps = create_dependency_tree(ctx, quiet=quiet)
    build_dir = getattr(options, 'build_dir', None)

    modules_by_cfile = {}
    to_compile = []
    for m in module_list:
        if build_dir:
            root = os.getcwd()  # distutil extension depends are relative to cwd
            def copy_to_build_dir(filepath, root=root):
                filepath_abs = os.path.abspath(filepath)
                if os.path.isabs(filepath):
                    filepath = filepath_abs
                if filepath_abs.startswith(root):
                    mod_dir = join_path(build_dir,
                            os.path.dirname(_relpath(filepath, root)))
                    copy_once_if_newer(filepath_abs, mod_dir)
            for dep in m.depends:
                copy_to_build_dir(dep)

        new_sources = []
        for source in m.sources:
            base, ext = os.path.splitext(source)
            if ext in ('.pyx', '.py'):
                if m.language == 'c++':
                    c_file = base + '.cpp'
                    options = cpp_options
                else:
                    c_file = base + '.c'
                    options = c_options

                # setup for out of place build directory if enabled
                if build_dir:
                    c_file = os.path.join(build_dir, c_file)
                    dir = os.path.dirname(c_file)
                    safe_makedirs_once(dir)

                if os.path.exists(c_file):
                    c_timestamp = os.path.getmtime(c_file)
                else:
                    c_timestamp = -1

                # Priority goes first to modified files, second to direct
                # dependents, and finally to indirect dependents.
                if c_timestamp < deps.timestamp(source):
                    dep_timestamp, dep = deps.timestamp(source), source
                    priority = 0
                else:
                    dep_timestamp, dep = deps.newest_dependency(source)
                    priority = 2 - (dep in deps.immediate_dependencies(source))
                if force or c_timestamp < dep_timestamp:
                    if not quiet:
                        if source == dep:
                            print("Compiling %s because it changed." % source)
                        else:
                            print("Compiling %s because it depends on %s." % (source, dep))
                    if not force and options.cache:
                        extra = m.language
                        fingerprint = deps.transitive_fingerprint(source, extra)
                    else:
                        fingerprint = None
                    to_compile.append((priority, source, c_file, fingerprint, quiet,
                                       options, not exclude_failures, module_metadata.get(m.name)))
                new_sources.append(c_file)
                if c_file not in modules_by_cfile:
                    modules_by_cfile[c_file] = [m]
                else:
                    modules_by_cfile[c_file].append(m)
            else:
                new_sources.append(source)
                if build_dir:
                    copy_to_build_dir(source)
        m.sources = new_sources

    if options.cache:
        if not os.path.exists(options.cache):
            os.makedirs(options.cache)
    to_compile.sort()
    # Drop "priority" component of "to_compile" entries and add a
    # simple progress indicator.
    N = len(to_compile)
    progress_fmt = "[{0:%d}/{1}] " % len(str(N))
    for i in range(N):
        progress = progress_fmt.format(i+1, N)
        to_compile[i] = to_compile[i][1:] + (progress,)

    if N <= 1:
        nthreads = 0
    if nthreads:
        # Requires multiprocessing (or Python >= 2.6)
        try:
            import multiprocessing
            pool = multiprocessing.Pool(
                nthreads, initializer=_init_multiprocessing_helper)
        except (ImportError, OSError):
            print("multiprocessing required for parallel cythonization")
            nthreads = 0
        else:
            # This is a bit more involved than it should be, because KeyboardInterrupts
            # break the multiprocessing workers when using a normal pool.map().
            # See, for example:
            # http://noswap.com/blog/python-multiprocessing-keyboardinterrupt
            try:
                result = pool.map_async(cythonize_one_helper, to_compile, chunksize=1)
                pool.close()
                while not result.ready():
                    try:
                        result.get(99999)  # seconds
                    except multiprocessing.TimeoutError:
                        pass
            except KeyboardInterrupt:
                pool.terminate()
                raise
            pool.join()
    if not nthreads:
        for args in to_compile:
            cythonize_one(*args)

    if exclude_failures:
        failed_modules = set()
        for c_file, modules in modules_by_cfile.items():
            if not os.path.exists(c_file):
                failed_modules.update(modules)
            elif os.path.getsize(c_file) < 200:
                f = io_open(c_file, 'r', encoding='iso8859-1')
                try:
                    if f.read(len('#error ')) == '#error ':
                        # dead compilation result
                        failed_modules.update(modules)
                finally:
                    f.close()
        if failed_modules:
            for module in failed_modules:
                module_list.remove(module)
            print("Failed compilations: %s" % ', '.join(sorted([
                module.name for module in failed_modules])))

    if options.cache:
        cleanup_cache(options.cache, getattr(options, 'cache_size', 1024 * 1024 * 100))
    # cythonize() is often followed by the (non-Python-buffered)
    # compiler output, flush now to avoid interleaving output.
    sys.stdout.flush()
    return module_list


if os.environ.get('XML_RESULTS'):
    compile_result_dir = os.environ['XML_RESULTS']
    def record_results(func):
        def with_record(*args):
            t = time.time()
            success = True
            try:
                try:
                    func(*args)
                except:
                    success = False
            finally:
                t = time.time() - t
                module = fully_qualified_name(args[0])
                name = "cythonize." + module
                failures = 1 - success
                if success:
                    failure_item = ""
                else:
                    failure_item = "failure"
                output = open(os.path.join(compile_result_dir, name + ".xml"), "w")
                output.write("""
                    <?xml version="1.0" ?>
                    <testsuite name="%(name)s" errors="0" failures="%(failures)s" tests="1" time="%(t)s">
                    <testcase classname="%(name)s" name="cythonize">
                    %(failure_item)s
                    </testcase>
                    </testsuite>
                """.strip() % locals())
                output.close()
        return with_record
else:
    def record_results(func):
        return func


# TODO: Share context? Issue: pyx processing leaks into pxd module
@record_results
def cythonize_one(pyx_file, c_file, fingerprint, quiet, options=None, raise_on_failure=True, embedded_metadata=None, progress=""):
    from ..Compiler.Main import compile, default_options
    from ..Compiler.Errors import CompileError, PyrexError

    if fingerprint:
        if not os.path.exists(options.cache):
            try:
                os.mkdir(options.cache)
            except:
                if not os.path.exists(options.cache):
                    raise
        # Cython-generated c files are highly compressible.
        # (E.g. a compression ratio of about 10 for Sage).
        fingerprint_file = join_path(
            options.cache, "%s-%s%s" % (os.path.basename(c_file), fingerprint, gzip_ext))
        if os.path.exists(fingerprint_file):
            if not quiet:
                print("%sFound compiled %s in cache" % (progress, pyx_file))
            os.utime(fingerprint_file, None)
            g = gzip_open(fingerprint_file, 'rb')
            try:
                f = open(c_file, 'wb')
                try:
                    shutil.copyfileobj(g, f)
                finally:
                    f.close()
            finally:
                g.close()
            return
    if not quiet:
        print("%sCythonizing %s" % (progress, pyx_file))
    if options is None:
        options = CompilationOptions(default_options)
    options.output_file = c_file
    options.embedded_metadata = embedded_metadata

    any_failures = 0
    try:
        result = compile([pyx_file], options)
        if result.num_errors > 0:
            any_failures = 1
    except (EnvironmentError, PyrexError) as e:
        sys.stderr.write('%s\n' % e)
        any_failures = 1
        # XXX
        import traceback
        traceback.print_exc()
    except Exception:
        if raise_on_failure:
            raise
        import traceback
        traceback.print_exc()
        any_failures = 1
    if any_failures:
        if raise_on_failure:
            raise CompileError(None, pyx_file)
        elif os.path.exists(c_file):
            os.remove(c_file)
    elif fingerprint:
        f = open(c_file, 'rb')
        try:
            g = gzip_open(fingerprint_file, 'wb')
            try:
                shutil.copyfileobj(f, g)
            finally:
                g.close()
        finally:
            f.close()


def cythonize_one_helper(m):
    import traceback
    try:
        return cythonize_one(*m)
    except Exception:
        traceback.print_exc()
        raise


def _init_multiprocessing_helper():
    # KeyboardInterrupt kills workers, so don't let them get it
    import signal
    signal.signal(signal.SIGINT, signal.SIG_IGN)


def cleanup_cache(cache, target_size, ratio=.85):
    try:
        p = subprocess.Popen(['du', '-s', '-k', os.path.abspath(cache)], stdout=subprocess.PIPE)
        res = p.wait()
        if res == 0:
            total_size = 1024 * int(p.stdout.read().strip().split()[0])
            if total_size < target_size:
                return
    except (OSError, ValueError):
        pass
    total_size = 0
    all = []
    for file in os.listdir(cache):
        path = join_path(cache, file)
        s = os.stat(path)
        total_size += s.st_size
        all.append((s.st_atime, s.st_size, path))
    if total_size > target_size:
        for time, size, file in reversed(sorted(all)):
            os.unlink(file)
            total_size -= size
            if total_size < target_size * ratio:
                break