This file is indexed.

/usr/lib/python3/dist-packages/distlib/metadata.py is in python3-distlib 0.2.2-1.

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
# -*- coding: utf-8 -*-
#
# Copyright (C) 2012 The Python Software Foundation.
# See LICENSE.txt and CONTRIBUTORS.txt.
#
"""Implementation of the Metadata for Python packages PEPs.

Supports all metadata formats (1.0, 1.1, 1.2, and 2.0 experimental).
"""
from __future__ import unicode_literals

import codecs
from email import message_from_file
import json
import logging
import re


from . import DistlibException, __version__
from .compat import StringIO, string_types, text_type
from .markers import interpret
from .util import extract_by_key, get_extras
from .version import get_scheme, PEP440_VERSION_RE

logger = logging.getLogger(__name__)


class MetadataMissingError(DistlibException):
    """A required metadata is missing"""


class MetadataConflictError(DistlibException):
    """Attempt to read or write metadata fields that are conflictual."""


class MetadataUnrecognizedVersionError(DistlibException):
    """Unknown metadata version number."""


class MetadataInvalidError(DistlibException):
    """A metadata value is invalid"""

# public API of this module
__all__ = ['Metadata', 'PKG_INFO_ENCODING', 'PKG_INFO_PREFERRED_VERSION']

# Encoding used for the PKG-INFO files
PKG_INFO_ENCODING = 'utf-8'

# preferred version. Hopefully will be changed
# to 1.2 once PEP 345 is supported everywhere
PKG_INFO_PREFERRED_VERSION = '1.1'

_LINE_PREFIX_1_2 = re.compile('\n       \|')
_LINE_PREFIX_PRE_1_2 = re.compile('\n        ')
_241_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
               'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email',
               'License')

_314_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
               'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email',
               'License', 'Classifier', 'Download-URL', 'Obsoletes',
               'Provides', 'Requires')

_314_MARKERS = ('Obsoletes', 'Provides', 'Requires', 'Classifier',
                'Download-URL')

_345_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
               'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email',
               'Maintainer', 'Maintainer-email', 'License',
               'Classifier', 'Download-URL', 'Obsoletes-Dist',
               'Project-URL', 'Provides-Dist', 'Requires-Dist',
               'Requires-Python', 'Requires-External')

_345_MARKERS = ('Provides-Dist', 'Requires-Dist', 'Requires-Python',
                'Obsoletes-Dist', 'Requires-External', 'Maintainer',
                'Maintainer-email', 'Project-URL')

_426_FIELDS = ('Metadata-Version', 'Name', 'Version', 'Platform',
               'Supported-Platform', 'Summary', 'Description',
               'Keywords', 'Home-page', 'Author', 'Author-email',
               'Maintainer', 'Maintainer-email', 'License',
               'Classifier', 'Download-URL', 'Obsoletes-Dist',
               'Project-URL', 'Provides-Dist', 'Requires-Dist',
               'Requires-Python', 'Requires-External', 'Private-Version',
               'Obsoleted-By', 'Setup-Requires-Dist', 'Extension',
               'Provides-Extra')

_426_MARKERS = ('Private-Version', 'Provides-Extra', 'Obsoleted-By',
                'Setup-Requires-Dist', 'Extension')

_ALL_FIELDS = set()
_ALL_FIELDS.update(_241_FIELDS)
_ALL_FIELDS.update(_314_FIELDS)
_ALL_FIELDS.update(_345_FIELDS)
_ALL_FIELDS.update(_426_FIELDS)

EXTRA_RE = re.compile(r'''extra\s*==\s*("([^"]+)"|'([^']+)')''')


def _version2fieldlist(version):
    if version == '1.0':
        return _241_FIELDS
    elif version == '1.1':
        return _314_FIELDS
    elif version == '1.2':
        return _345_FIELDS
    elif version == '2.0':
        return _426_FIELDS
    raise MetadataUnrecognizedVersionError(version)


def _best_version(fields):
    """Detect the best version depending on the fields used."""
    def _has_marker(keys, markers):
        for marker in markers:
            if marker in keys:
                return True
        return False

    keys = []
    for key, value in fields.items():
        if value in ([], 'UNKNOWN', None):
            continue
        keys.append(key)

    possible_versions = ['1.0', '1.1', '1.2', '2.0']

    # first let's try to see if a field is not part of one of the version
    for key in keys:
        if key not in _241_FIELDS and '1.0' in possible_versions:
            possible_versions.remove('1.0')
        if key not in _314_FIELDS and '1.1' in possible_versions:
            possible_versions.remove('1.1')
        if key not in _345_FIELDS and '1.2' in possible_versions:
            possible_versions.remove('1.2')
        if key not in _426_FIELDS and '2.0' in possible_versions:
            possible_versions.remove('2.0')

    # possible_version contains qualified versions
    if len(possible_versions) == 1:
        return possible_versions[0]   # found !
    elif len(possible_versions) == 0:
        raise MetadataConflictError('Unknown metadata set')

    # let's see if one unique marker is found
    is_1_1 = '1.1' in possible_versions and _has_marker(keys, _314_MARKERS)
    is_1_2 = '1.2' in possible_versions and _has_marker(keys, _345_MARKERS)
    is_2_0 = '2.0' in possible_versions and _has_marker(keys, _426_MARKERS)
    if int(is_1_1) + int(is_1_2) + int(is_2_0) > 1:
        raise MetadataConflictError('You used incompatible 1.1/1.2/2.0 fields')

    # we have the choice, 1.0, or 1.2, or 2.0
    #   - 1.0 has a broken Summary field but works with all tools
    #   - 1.1 is to avoid
    #   - 1.2 fixes Summary but has little adoption
    #   - 2.0 adds more features and is very new
    if not is_1_1 and not is_1_2 and not is_2_0:
        # we couldn't find any specific marker
        if PKG_INFO_PREFERRED_VERSION in possible_versions:
            return PKG_INFO_PREFERRED_VERSION
    if is_1_1:
        return '1.1'
    if is_1_2:
        return '1.2'

    return '2.0'

_ATTR2FIELD = {
    'metadata_version': 'Metadata-Version',
    'name': 'Name',
    'version': 'Version',
    'platform': 'Platform',
    'supported_platform': 'Supported-Platform',
    'summary': 'Summary',
    'description': 'Description',
    'keywords': 'Keywords',
    'home_page': 'Home-page',
    'author': 'Author',
    'author_email': 'Author-email',
    'maintainer': 'Maintainer',
    'maintainer_email': 'Maintainer-email',
    'license': 'License',
    'classifier': 'Classifier',
    'download_url': 'Download-URL',
    'obsoletes_dist': 'Obsoletes-Dist',
    'provides_dist': 'Provides-Dist',
    'requires_dist': 'Requires-Dist',
    'setup_requires_dist': 'Setup-Requires-Dist',
    'requires_python': 'Requires-Python',
    'requires_external': 'Requires-External',
    'requires': 'Requires',
    'provides': 'Provides',
    'obsoletes': 'Obsoletes',
    'project_url': 'Project-URL',
    'private_version': 'Private-Version',
    'obsoleted_by': 'Obsoleted-By',
    'extension': 'Extension',
    'provides_extra': 'Provides-Extra',
}

_PREDICATE_FIELDS = ('Requires-Dist', 'Obsoletes-Dist', 'Provides-Dist')
_VERSIONS_FIELDS = ('Requires-Python',)
_VERSION_FIELDS = ('Version',)
_LISTFIELDS = ('Platform', 'Classifier', 'Obsoletes',
               'Requires', 'Provides', 'Obsoletes-Dist',
               'Provides-Dist', 'Requires-Dist', 'Requires-External',
               'Project-URL', 'Supported-Platform', 'Setup-Requires-Dist',
               'Provides-Extra', 'Extension')
_LISTTUPLEFIELDS = ('Project-URL',)

_ELEMENTSFIELD = ('Keywords',)

_UNICODEFIELDS = ('Author', 'Maintainer', 'Summary', 'Description')

_MISSING = object()

_FILESAFE = re.compile('[^A-Za-z0-9.]+')


def _get_name_and_version(name, version, for_filename=False):
    """Return the distribution name with version.

    If for_filename is true, return a filename-escaped form."""
    if for_filename:
        # For both name and version any runs of non-alphanumeric or '.'
        # characters are replaced with a single '-'.  Additionally any
        # spaces in the version string become '.'
        name = _FILESAFE.sub('-', name)
        version = _FILESAFE.sub('-', version.replace(' ', '.'))
    return '%s-%s' % (name, version)


class LegacyMetadata(object):
    """The legacy metadata of a release.

    Supports versions 1.0, 1.1 and 1.2 (auto-detected). You can
    instantiate the class with one of these arguments (or none):
    - *path*, the path to a metadata file
    - *fileobj* give a file-like object with metadata as content
    - *mapping* is a dict-like object
    - *scheme* is a version scheme name
    """
    # TODO document the mapping API and UNKNOWN default key

    def __init__(self, path=None, fileobj=None, mapping=None,
                 scheme='default'):
        if [path, fileobj, mapping].count(None) < 2:
            raise TypeError('path, fileobj and mapping are exclusive')
        self._fields = {}
        self.requires_files = []
        self._dependencies = None
        self.scheme = scheme
        if path is not None:
            self.read(path)
        elif fileobj is not None:
            self.read_file(fileobj)
        elif mapping is not None:
            self.update(mapping)
            self.set_metadata_version()

    def set_metadata_version(self):
        self._fields['Metadata-Version'] = _best_version(self._fields)

    def _write_field(self, fileobj, name, value):
        fileobj.write('%s: %s\n' % (name, value))

    def __getitem__(self, name):
        return self.get(name)

    def __setitem__(self, name, value):
        return self.set(name, value)

    def __delitem__(self, name):
        field_name = self._convert_name(name)
        try:
            del self._fields[field_name]
        except KeyError:
            raise KeyError(name)

    def __contains__(self, name):
        return (name in self._fields or
                self._convert_name(name) in self._fields)

    def _convert_name(self, name):
        if name in _ALL_FIELDS:
            return name
        name = name.replace('-', '_').lower()
        return _ATTR2FIELD.get(name, name)

    def _default_value(self, name):
        if name in _LISTFIELDS or name in _ELEMENTSFIELD:
            return []
        return 'UNKNOWN'

    def _remove_line_prefix(self, value):
        if self.metadata_version in ('1.0', '1.1'):
            return _LINE_PREFIX_PRE_1_2.sub('\n', value)
        else:
            return _LINE_PREFIX_1_2.sub('\n', value)

    def __getattr__(self, name):
        if name in _ATTR2FIELD:
            return self[name]
        raise AttributeError(name)

    #
    # Public API
    #

#    dependencies = property(_get_dependencies, _set_dependencies)

    def get_fullname(self, filesafe=False):
        """Return the distribution name with version.

        If filesafe is true, return a filename-escaped form."""
        return _get_name_and_version(self['Name'], self['Version'], filesafe)

    def is_field(self, name):
        """return True if name is a valid metadata key"""
        name = self._convert_name(name)
        return name in _ALL_FIELDS

    def is_multi_field(self, name):
        name = self._convert_name(name)
        return name in _LISTFIELDS

    def read(self, filepath):
        """Read the metadata values from a file path."""
        fp = codecs.open(filepath, 'r', encoding='utf-8')
        try:
            self.read_file(fp)
        finally:
            fp.close()

    def read_file(self, fileob):
        """Read the metadata values from a file object."""
        msg = message_from_file(fileob)
        self._fields['Metadata-Version'] = msg['metadata-version']

        # When reading, get all the fields we can
        for field in _ALL_FIELDS:
            if field not in msg:
                continue
            if field in _LISTFIELDS:
                # we can have multiple lines
                values = msg.get_all(field)
                if field in _LISTTUPLEFIELDS and values is not None:
                    values = [tuple(value.split(',')) for value in values]
                self.set(field, values)
            else:
                # single line
                value = msg[field]
                if value is not None and value != 'UNKNOWN':
                    self.set(field, value)
        self.set_metadata_version()

    def write(self, filepath, skip_unknown=False):
        """Write the metadata fields to filepath."""
        fp = codecs.open(filepath, 'w', encoding='utf-8')
        try:
            self.write_file(fp, skip_unknown)
        finally:
            fp.close()

    def write_file(self, fileobject, skip_unknown=False):
        """Write the PKG-INFO format data to a file object."""
        self.set_metadata_version()

        for field in _version2fieldlist(self['Metadata-Version']):
            values = self.get(field)
            if skip_unknown and values in ('UNKNOWN', [], ['UNKNOWN']):
                continue
            if field in _ELEMENTSFIELD:
                self._write_field(fileobject, field, ','.join(values))
                continue
            if field not in _LISTFIELDS:
                if field == 'Description':
                    if self.metadata_version in ('1.0', '1.1'):
                        values = values.replace('\n', '\n        ')
                    else:
                        values = values.replace('\n', '\n       |')
                values = [values]

            if field in _LISTTUPLEFIELDS:
                values = [','.join(value) for value in values]

            for value in values:
                self._write_field(fileobject, field, value)

    def update(self, other=None, **kwargs):
        """Set metadata values from the given iterable `other` and kwargs.

        Behavior is like `dict.update`: If `other` has a ``keys`` method,
        they are looped over and ``self[key]`` is assigned ``other[key]``.
        Else, ``other`` is an iterable of ``(key, value)`` iterables.

        Keys that don't match a metadata field or that have an empty value are
        dropped.
        """
        def _set(key, value):
            if key in _ATTR2FIELD and value:
                self.set(self._convert_name(key), value)

        if not other:
            # other is None or empty container
            pass
        elif hasattr(other, 'keys'):
            for k in other.keys():
                _set(k, other[k])
        else:
            for k, v in other:
                _set(k, v)

        if kwargs:
            for k, v in kwargs.items():
                _set(k, v)

    def set(self, name, value):
        """Control then set a metadata field."""
        name = self._convert_name(name)

        if ((name in _ELEMENTSFIELD or name == 'Platform') and
            not isinstance(value, (list, tuple))):
            if isinstance(value, string_types):
                value = [v.strip() for v in value.split(',')]
            else:
                value = []
        elif (name in _LISTFIELDS and
              not isinstance(value, (list, tuple))):
            if isinstance(value, string_types):
                value = [value]
            else:
                value = []

        if logger.isEnabledFor(logging.WARNING):
            project_name = self['Name']

            scheme = get_scheme(self.scheme)
            if name in _PREDICATE_FIELDS and value is not None:
                for v in value:
                    # check that the values are valid
                    if not scheme.is_valid_matcher(v.split(';')[0]):
                        logger.warning(
                            '%r: %r is not valid (field %r)',
                            project_name, v, name)
            # FIXME this rejects UNKNOWN, is that right?
            elif name in _VERSIONS_FIELDS and value is not None:
                if not scheme.is_valid_constraint_list(value):
                    logger.warning('%r: %r is not a valid version (field %r)',
                                   project_name, value, name)
            elif name in _VERSION_FIELDS and value is not None:
                if not scheme.is_valid_version(value):
                    logger.warning('%r: %r is not a valid version (field %r)',
                                   project_name, value, name)

        if name in _UNICODEFIELDS:
            if name == 'Description':
                value = self._remove_line_prefix(value)

        self._fields[name] = value

    def get(self, name, default=_MISSING):
        """Get a metadata field."""
        name = self._convert_name(name)
        if name not in self._fields:
            if default is _MISSING:
                default = self._default_value(name)
            return default
        if name in _UNICODEFIELDS:
            value = self._fields[name]
            return value
        elif name in _LISTFIELDS:
            value = self._fields[name]
            if value is None:
                return []
            res = []
            for val in value:
                if name not in _LISTTUPLEFIELDS:
                    res.append(val)
                else:
                    # That's for Project-URL
                    res.append((val[0], val[1]))
            return res

        elif name in _ELEMENTSFIELD:
            value = self._fields[name]
            if isinstance(value, string_types):
                return value.split(',')
        return self._fields[name]

    def check(self, strict=False):
        """Check if the metadata is compliant. If strict is True then raise if
        no Name or Version are provided"""
        self.set_metadata_version()

        # XXX should check the versions (if the file was loaded)
        missing, warnings = [], []

        for attr in ('Name', 'Version'):  # required by PEP 345
            if attr not in self:
                missing.append(attr)

        if strict and missing != []:
            msg = 'missing required metadata: %s' % ', '.join(missing)
            raise MetadataMissingError(msg)

        for attr in ('Home-page', 'Author'):
            if attr not in self:
                missing.append(attr)

        # checking metadata 1.2 (XXX needs to check 1.1, 1.0)
        if self['Metadata-Version'] != '1.2':
            return missing, warnings

        scheme = get_scheme(self.scheme)

        def are_valid_constraints(value):
            for v in value:
                if not scheme.is_valid_matcher(v.split(';')[0]):
                    return False
            return True

        for fields, controller in ((_PREDICATE_FIELDS, are_valid_constraints),
                                   (_VERSIONS_FIELDS,
                                    scheme.is_valid_constraint_list),
                                   (_VERSION_FIELDS,
                                    scheme.is_valid_version)):
            for field in fields:
                value = self.get(field, None)
                if value is not None and not controller(value):
                    warnings.append('Wrong value for %r: %s' % (field, value))

        return missing, warnings

    def todict(self, skip_missing=False):
        """Return fields as a dict.

        Field names will be converted to use the underscore-lowercase style
        instead of hyphen-mixed case (i.e. home_page instead of Home-page).
        """
        self.set_metadata_version()

        mapping_1_0 = (
            ('metadata_version', 'Metadata-Version'),
            ('name', 'Name'),
            ('version', 'Version'),
            ('summary', 'Summary'),
            ('home_page', 'Home-page'),
            ('author', 'Author'),
            ('author_email', 'Author-email'),
            ('license', 'License'),
            ('description', 'Description'),
            ('keywords', 'Keywords'),
            ('platform', 'Platform'),
            ('classifiers', 'Classifier'),
            ('download_url', 'Download-URL'),
        )

        data = {}
        for key, field_name in mapping_1_0:
            if not skip_missing or field_name in self._fields:
                data[key] = self[field_name]

        if self['Metadata-Version'] == '1.2':
            mapping_1_2 = (
                ('requires_dist', 'Requires-Dist'),
                ('requires_python', 'Requires-Python'),
                ('requires_external', 'Requires-External'),
                ('provides_dist', 'Provides-Dist'),
                ('obsoletes_dist', 'Obsoletes-Dist'),
                ('project_url', 'Project-URL'),
                ('maintainer', 'Maintainer'),
                ('maintainer_email', 'Maintainer-email'),
            )
            for key, field_name in mapping_1_2:
                if not skip_missing or field_name in self._fields:
                    if key != 'project_url':
                        data[key] = self[field_name]
                    else:
                        data[key] = [','.join(u) for u in self[field_name]]

        elif self['Metadata-Version'] == '1.1':
            mapping_1_1 = (
                ('provides', 'Provides'),
                ('requires', 'Requires'),
                ('obsoletes', 'Obsoletes'),
            )
            for key, field_name in mapping_1_1:
                if not skip_missing or field_name in self._fields:
                    data[key] = self[field_name]

        return data

    def add_requirements(self, requirements):
        if self['Metadata-Version'] == '1.1':
            # we can't have 1.1 metadata *and* Setuptools requires
            for field in ('Obsoletes', 'Requires', 'Provides'):
                if field in self:
                    del self[field]
        self['Requires-Dist'] += requirements

    # Mapping API
    # TODO could add iter* variants

    def keys(self):
        return list(_version2fieldlist(self['Metadata-Version']))

    def __iter__(self):
        for key in self.keys():
            yield key

    def values(self):
        return [self[key] for key in self.keys()]

    def items(self):
        return [(key, self[key]) for key in self.keys()]

    def __repr__(self):
        return '<%s %s %s>' % (self.__class__.__name__, self.name,
                               self.version)


METADATA_FILENAME = 'pydist.json'
WHEEL_METADATA_FILENAME = 'metadata.json'


class Metadata(object):
    """
    The metadata of a release. This implementation uses 2.0 (JSON)
    metadata where possible. If not possible, it wraps a LegacyMetadata
    instance which handles the key-value metadata format.
    """

    METADATA_VERSION_MATCHER = re.compile('^\d+(\.\d+)*$')

    NAME_MATCHER = re.compile('^[0-9A-Z]([0-9A-Z_.-]*[0-9A-Z])?$', re.I)

    VERSION_MATCHER = PEP440_VERSION_RE

    SUMMARY_MATCHER = re.compile('.{1,2047}')

    METADATA_VERSION = '2.0'

    GENERATOR = 'distlib (%s)' % __version__

    MANDATORY_KEYS = {
        'name': (),
        'version': (),
        'summary': ('legacy',),
    }

    INDEX_KEYS = ('name version license summary description author '
                  'author_email keywords platform home_page classifiers '
                  'download_url')

    DEPENDENCY_KEYS = ('extras run_requires test_requires build_requires '
                       'dev_requires provides meta_requires obsoleted_by '
                       'supports_environments')

    SYNTAX_VALIDATORS = {
        'metadata_version': (METADATA_VERSION_MATCHER, ()),
        'name': (NAME_MATCHER, ('legacy',)),
        'version': (VERSION_MATCHER, ('legacy',)),
        'summary': (SUMMARY_MATCHER, ('legacy',)),
    }

    __slots__ = ('_legacy', '_data', 'scheme')

    def __init__(self, path=None, fileobj=None, mapping=None,
                 scheme='default'):
        if [path, fileobj, mapping].count(None) < 2:
            raise TypeError('path, fileobj and mapping are exclusive')
        self._legacy = None
        self._data = None
        self.scheme = scheme
        #import pdb; pdb.set_trace()
        if mapping is not None:
            try:
                self._validate_mapping(mapping, scheme)
                self._data = mapping
            except MetadataUnrecognizedVersionError:
                self._legacy = LegacyMetadata(mapping=mapping, scheme=scheme)
                self.validate()
        else:
            data = None
            if path:
                with open(path, 'rb') as f:
                    data = f.read()
            elif fileobj:
                data = fileobj.read()
            if data is None:
                # Initialised with no args - to be added
                self._data = {
                    'metadata_version': self.METADATA_VERSION,
                    'generator': self.GENERATOR,
                }
            else:
                if not isinstance(data, text_type):
                    data = data.decode('utf-8')
                try:
                    self._data = json.loads(data)
                    self._validate_mapping(self._data, scheme)
                except ValueError:
                    # Note: MetadataUnrecognizedVersionError does not
                    # inherit from ValueError (it's a DistlibException,
                    # which should not inherit from ValueError).
                    # The ValueError comes from the json.load - if that
                    # succeeds and we get a validation error, we want
                    # that to propagate
                    self._legacy = LegacyMetadata(fileobj=StringIO(data),
                                                  scheme=scheme)
                    self.validate()

    common_keys = set(('name', 'version', 'license', 'keywords', 'summary'))

    none_list = (None, list)
    none_dict = (None, dict)

    mapped_keys = {
        'run_requires': ('Requires-Dist', list),
        'build_requires': ('Setup-Requires-Dist', list),
        'dev_requires': none_list,
        'test_requires': none_list,
        'meta_requires': none_list,
        'extras': ('Provides-Extra', list),
        'modules': none_list,
        'namespaces': none_list,
        'exports': none_dict,
        'commands': none_dict,
        'classifiers': ('Classifier', list),
        'source_url': ('Download-URL', None),
        'metadata_version': ('Metadata-Version', None),
    }

    del none_list, none_dict

    def __getattribute__(self, key):
        common = object.__getattribute__(self, 'common_keys')
        mapped = object.__getattribute__(self, 'mapped_keys')
        if key in mapped:
            lk, maker = mapped[key]
            if self._legacy:
                if lk is None:
                    result = None if maker is None else maker()
                else:
                    result = self._legacy.get(lk)
            else:
                value = None if maker is None else maker()
                if key not in ('commands', 'exports', 'modules', 'namespaces',
                               'classifiers'):
                    result = self._data.get(key, value)
                else:
                    # special cases for PEP 459
                    sentinel = object()
                    result = sentinel
                    d = self._data.get('extensions')
                    if d:
                        if key == 'commands':
                            result = d.get('python.commands', value)
                        elif key == 'classifiers':
                            d = d.get('python.details')
                            if d:
                                result = d.get(key, value)
                        else:
                            d = d.get('python.exports')
                            if d:
                                result = d.get(key, value)
                    if result is sentinel:
                        result = value
        elif key not in common:
            result = object.__getattribute__(self, key)
        elif self._legacy:
            result = self._legacy.get(key)
        else:
            result = self._data.get(key)
        return result

    def _validate_value(self, key, value, scheme=None):
        if key in self.SYNTAX_VALIDATORS:
            pattern, exclusions = self.SYNTAX_VALIDATORS[key]
            if (scheme or self.scheme) not in exclusions:
                m = pattern.match(value)
                if not m:
                    raise MetadataInvalidError('%r is an invalid value for '
                                               'the %r property' % (value,
                                                                    key))

    def __setattr__(self, key, value):
        self._validate_value(key, value)
        common = object.__getattribute__(self, 'common_keys')
        mapped = object.__getattribute__(self, 'mapped_keys')
        if key in mapped:
            lk, _ = mapped[key]
            if self._legacy:
                if lk is None:
                    raise NotImplementedError
                self._legacy[lk] = value
            elif key not in ('commands', 'exports', 'modules', 'namespaces',
                             'classifiers'):
                self._data[key] = value
            else:
                # special cases for PEP 459
                d = self._data.setdefault('extensions', {})
                if key == 'commands':
                    d['python.commands'] = value
                elif key == 'classifiers':
                    d = d.setdefault('python.details', {})
                    d[key] = value
                else:
                    d = d.setdefault('python.exports', {})
                    d[key] = value
        elif key not in common:
            object.__setattr__(self, key, value)
        else:
            if key == 'keywords':
                if isinstance(value, string_types):
                    value = value.strip()
                    if value:
                        value = value.split()
                    else:
                        value = []
            if self._legacy:
                self._legacy[key] = value
            else:
                self._data[key] = value

    @property
    def name_and_version(self):
        return _get_name_and_version(self.name, self.version, True)

    @property
    def provides(self):
        if self._legacy:
            result = self._legacy['Provides-Dist']
        else:
            result = self._data.setdefault('provides', [])
        s = '%s (%s)' % (self.name, self.version)
        if s not in result:
            result.append(s)
        return result

    @provides.setter
    def provides(self, value):
        if self._legacy:
            self._legacy['Provides-Dist'] = value
        else:
            self._data['provides'] = value

    def get_requirements(self, reqts, extras=None, env=None):
        """
        Base method to get dependencies, given a set of extras
        to satisfy and an optional environment context.
        :param reqts: A list of sometimes-wanted dependencies,
                      perhaps dependent on extras and environment.
        :param extras: A list of optional components being requested.
        :param env: An optional environment for marker evaluation.
        """
        if self._legacy:
            result = reqts
        else:
            result = []
            extras = get_extras(extras or [], self.extras)
            for d in reqts:
                if 'extra' not in d and 'environment' not in d:
                    # unconditional
                    include = True
                else:
                    if 'extra' not in d:
                        # Not extra-dependent - only environment-dependent
                        include = True
                    else:
                        include = d.get('extra') in extras
                    if include:
                        # Not excluded because of extras, check environment
                        marker = d.get('environment')
                        if marker:
                            include = interpret(marker, env)
                if include:
                    result.extend(d['requires'])
            for key in ('build', 'dev', 'test'):
                e = ':%s:' % key
                if e in extras:
                    extras.remove(e)
                    # A recursive call, but it should terminate since 'test'
                    # has been removed from the extras
                    reqts = self._data.get('%s_requires' % key, [])
                    result.extend(self.get_requirements(reqts, extras=extras,
                                                        env=env))
        return result

    @property
    def dictionary(self):
        if self._legacy:
            return self._from_legacy()
        return self._data

    @property
    def dependencies(self):
        if self._legacy:
            raise NotImplementedError
        else:
            return extract_by_key(self._data, self.DEPENDENCY_KEYS)

    @dependencies.setter
    def dependencies(self, value):
        if self._legacy:
            raise NotImplementedError
        else:
            self._data.update(value)

    def _validate_mapping(self, mapping, scheme):
        if mapping.get('metadata_version') != self.METADATA_VERSION:
            raise MetadataUnrecognizedVersionError()
        missing = []
        for key, exclusions in self.MANDATORY_KEYS.items():
            if key not in mapping:
                if scheme not in exclusions:
                    missing.append(key)
        if missing:
            msg = 'Missing metadata items: %s' % ', '.join(missing)
            raise MetadataMissingError(msg)
        for k, v in mapping.items():
            self._validate_value(k, v, scheme)

    def validate(self):
        if self._legacy:
            missing, warnings = self._legacy.check(True)
            if missing or warnings:
                logger.warning('Metadata: missing: %s, warnings: %s',
                               missing, warnings)
        else:
            self._validate_mapping(self._data, self.scheme)

    def todict(self):
        if self._legacy:
            return self._legacy.todict(True)
        else:
            result = extract_by_key(self._data, self.INDEX_KEYS)
            return result

    def _from_legacy(self):
        assert self._legacy and not self._data
        result = {
            'metadata_version': self.METADATA_VERSION,
            'generator': self.GENERATOR,
        }
        lmd = self._legacy.todict(True)     # skip missing ones
        for k in ('name', 'version', 'license', 'summary', 'description',
                  'classifier'):
            if k in lmd:
                if k == 'classifier':
                    nk = 'classifiers'
                else:
                    nk = k
                result[nk] = lmd[k]
        kw = lmd.get('Keywords', [])
        if kw == ['']:
            kw = []
        result['keywords'] = kw
        keys = (('requires_dist', 'run_requires'),
                ('setup_requires_dist', 'build_requires'))
        for ok, nk in keys:
            if ok in lmd and lmd[ok]:
                result[nk] = [{'requires': lmd[ok]}]
        result['provides'] = self.provides
        author = {}
        maintainer = {}
        return result

    LEGACY_MAPPING = {
        'name': 'Name',
        'version': 'Version',
        'license': 'License',
        'summary': 'Summary',
        'description': 'Description',
        'classifiers': 'Classifier',
    }

    def _to_legacy(self):
        def process_entries(entries):
            reqts = set()
            for e in entries:
                extra = e.get('extra')
                env = e.get('environment')
                rlist = e['requires']
                for r in rlist:
                    if not env and not extra:
                        reqts.add(r)
                    else:
                        marker = ''
                        if extra:
                            marker = 'extra == "%s"' % extra
                        if env:
                            if marker:
                                marker = '(%s) and %s' % (env, marker)
                            else:
                                marker = env
                        reqts.add(';'.join((r, marker)))
            return reqts

        assert self._data and not self._legacy
        result = LegacyMetadata()
        nmd = self._data
        for nk, ok in self.LEGACY_MAPPING.items():
            if nk in nmd:
                result[ok] = nmd[nk]
        r1 = process_entries(self.run_requires + self.meta_requires)
        r2 = process_entries(self.build_requires + self.dev_requires)
        if self.extras:
            result['Provides-Extra'] = sorted(self.extras)
        result['Requires-Dist'] = sorted(r1)
        result['Setup-Requires-Dist'] = sorted(r2)
        # TODO: other fields such as contacts
        return result

    def write(self, path=None, fileobj=None, legacy=False, skip_unknown=True):
        if [path, fileobj].count(None) != 1:
            raise ValueError('Exactly one of path and fileobj is needed')
        self.validate()
        if legacy:
            if self._legacy:
                legacy_md = self._legacy
            else:
                legacy_md = self._to_legacy()
            if path:
                legacy_md.write(path, skip_unknown=skip_unknown)
            else:
                legacy_md.write_file(fileobj, skip_unknown=skip_unknown)
        else:
            if self._legacy:
                d = self._from_legacy()
            else:
                d = self._data
            if fileobj:
                json.dump(d, fileobj, ensure_ascii=True, indent=2,
                          sort_keys=True)
            else:
                with codecs.open(path, 'w', 'utf-8') as f:
                    json.dump(d, f, ensure_ascii=True, indent=2,
                              sort_keys=True)

    def add_requirements(self, requirements):
        if self._legacy:
            self._legacy.add_requirements(requirements)
        else:
            run_requires = self._data.setdefault('run_requires', [])
            always = None
            for entry in run_requires:
                if 'environment' not in entry and 'extra' not in entry:
                    always = entry
                    break
            if always is None:
                always = { 'requires': requirements }
                run_requires.insert(0, always)
            else:
                rset = set(always['requires']) | set(requirements)
                always['requires'] = sorted(rset)

    def __repr__(self):
        name = self.name or '(no name)'
        version = self.version or 'no version'
        return '<%s %s %s (%s)>' % (self.__class__.__name__,
                                    self.metadata_version, name, version)