This file is indexed.

/usr/share/pyshared/mx/Misc/ConfigFile.py is in python-egenix-mxtools 3.2.1-1ubuntu1.

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
""" ConfigFile -- Interface to simple template based configuration files.

    The format of these files is as follows:

    globalvar = 2

    [ABC]
    a = 1
    b = abc.html
    c = text with spaces

    [DEF]
    a = 2
    b = a + 3
    c = a string

    Entries in square brackets indicate new subsections. Global
    variables may be set prior to starting any subsection.

    Empty lines and lines starting with '#' or ';' (comments) are
    ignored.

    Indentation is not necessary; lines can start at any column.

    Entries may span multiple lines by using '\' continuations
    at the line ends, e.g.

    [Continuation]
    a = first line\
        second line

    The lines are stripped of any white space before removing the
    trailing '\' and concatenating them. Comment lines are removed as
    well.

    To parse these files, a template in form of a class including
    subclasses (identifying the subsections) must be given to the
    reader. This template defines which sections and attributes are
    known. All others are rejected.  A sample template for the above
    looks like this:

    from mx.Misc.ConfigFile import *
    class Template(ConfigNamespace):

        global = IntegerEntry()

        class ABC(ConfigSection):
            a = IntegerEntry('0')
            b = StringEntry('default.html')
            c = StringEntry()

        class DEF(ConfigSection):
            a = IntegerEntry('0')
            b = EvalEntry('0')
            c = StringEntry('default value')

    The main class representing the global namespace of the ini file
    must have ConfigNamespace as baseclass. It may contain any number
    of ConfigSection subclasses each defining parsed attributes. 

    The ini file may only contain entries defined in this template.
    In case an unknown section is found, the main class is looked up
    for a ConfigSection subclass with name 'DefaultSection'. This
    section object is then taken as template for a new section
    of the given name.

    The same feature is available for attributes in sections. In case
    a given attribute is not found in the templates, the section's
    'DefaultAttribute' attribute is deepcopied and the used as
    attribute template.

    Needs mxTools to be installed.

    XXX Add support for long strings (including embedded control
        characters and spanning multiple lines)

    Copyright (c) 2000, Marc-Andre Lemburg; All Rights Reserved.
    Copyright (c) 2000-2010, eGenix.com Software GmbH; All Rights Reserved.
    See the documentation for further information on copyrights,
    or contact the author. All Rights Reserved.

"""
import copy,re,types,exceptions,sys,os
import mx.Tools.NewBuiltins
from mx.Tools import freeze
import Namespace

### Globals

# Characters declaring comment lines
COMMENT_CHARS = ('#', ';')

# Print debug information ?
_debug = 0

### Errors

class Error(exceptions.StandardError):
    pass

### Helpers

shell_var = re.compile('(?:\$([a-zA-Z0-9._]+)|\${([^}]*)})')

def expand_vars(text,locals,globals,

                shell_var=shell_var):

    """ Expands all variables of the form $var or ${var} using
        the dictionaries locals,globals,os.environ in that order
        as database.

        Default value is the empty string, just like for shell
        environment variables.
        
    """
    while 1:
        m = shell_var.search(text)
        if not m:
            break
        g = m.groups()
        varpath = (g[0] or g[1]).split('.')
        varname = varpath[0]
        # Find object with name varname
        value = locals.get(varname,None)
        if value is None:
            value = globals.get(varname,None)
            if value is None:
                value = os.environ.get(varname,'')
        # Now get the requested attribute
        for attr in varpath[1:]:
            try:
                value = getattr(value,attr)
            except AttributeError:
                raise Error,'attribute "%s" undefined' % attr
        # Reformat text by inserting value as string
        l,r = m.span()
        if isinstance(value,Entry):
            entry = value
            if entry.value is NotGiven:
                entry.parse(entry.default,locals,globals)
            value = entry.value
        text = text[:l] + str(value) + text[r:]
    return text

### Template entry fields

class Entry:

    """ Converts the value to another datatype depending on the
        .converters attribute.

        Each of those functions is applied to the value. The first one
        to not raise an exception succeeds.
        
    """
    # Value
    value = NotGiven

    # Default value
    default = ''

    # Converters to be tried; order is important the first successful
    # one wins
    converters = (int,float,str)


    def __init__(self,default=NotGiven):

        if default is not NotGiven:
            self.default = default

    def parse(self,text,locals,globals):

        """ Parse text according to the namespace dictionaries
            locals and globals.

            Sets self.value and returns the parsed value as well.
            
        """
        text = self.pre_process(str(text),locals,globals)
        for converter in self.converters:
            try:
                value = converter(text)
                break
            except:
                lastexc = sys.exc_info()[1]
        else:
            # Reraise the last exception
            raise lastexc
        lastexc = None
        self.value = value = self.post_process(value,locals,globals)
        return value

    def pre_process(self,text,locals,globals,

                    expand_vars=expand_vars):

        """ Preprocess the text value.

            Default behaviour is to strip the text and then
            apply variable expansion.

        """
        return expand_vars(text.strip(),locals,globals)

    def post_process(self,value,locals,globals):

        """ Postprocess the value after conversion has been
            applied.

            The default behaviour is to leave it as it is.
        """
        return value

    def __str__(self):
        
        """ Return a stringified version of self.value.

            The default value is parsed in case no value has yet been
            set.

        """
        if self.value is NotGiven:
            self.parse(self.default,{},{})
        return str(self.value)

###

def integer_value(value):

    """ Convert value to an integer.

        Takes base indicators into account, such as 0x for base-16,
        0 for base-7.

    """
    return int(value, 0)

class IntegerEntry(Entry):

    """ Converts the value to an integer.
    """
    converters = (integer_value,)
        
class FloatEntry(Entry):

    """ Converts the value to a float.
    """
    converters = (float,)
        
class NumericEntry(Entry):

    """ Converts the value to a number (integer or float).
    """
    converters = (integer_value, float)
        
class StringEntry(Entry):

    """ Converts the value to a string.
    """
    converters = (str,)

def comma_list(text,

               map=map,tuple=tuple):

    return [x.strip() for x in text.split(',')]

def spaced_list(text,

                map=map,tuple=tuple):

    return [x.strip() for x in text.split()]

class TupleEntry(Entry):

    """ Converts the value to a tuple of strings.

        value must be a string with entries separated by ','. Entries
        are split at each occurance of ',' and then stripped of
        surrounding spaces.
        
    """
    converters = (comma_list,)

    def post_process(self,value,locals,globals):

        return tuple(value)

# Alias
StringTupleEntry = TupleEntry
CommaTupleEntry = TupleEntry

class ListEntry(Entry):

    """ Converts the value to a list of strings.

        value must be a string with entries separated by ','. Entries
        are split at each occurance of ',' and then stripped of
        surrounding spaces.
        
    """
    converters = (comma_list,)

# Alias
StringListEntry = ListEntry
CommaListEntry = ListEntry

class SpacedTupleEntry(TupleEntry):

    """ Converts the value to a tuple of strings.

        value must be a string with entries separated by
        whitespace. Entries are split at each occurance of whitespace;
        surrounding spaces is removed.

    """
    converters = (spaced_list,)

class SpacedListEntry(ListEntry):

    """ Converts the value to a list of strings.

        value must be a string with entries separated by
        whitespace. Entries are split at each occurance of whitespace;
        surrounding spaces is removed.

    """
    converters = (spaced_list,)

class FileEntry(Entry):

    """ Entry field for an OS file.
    """
    converters = (str,)

class PathEntry(Entry):

    """ Entry field for an OS path.

        Paths will always end with os.sep if given.
    """
    converters = (str,)

    def post_process(self,value,locals,globals):

        if value and value[-1] != os.sep:
            value = value + os.sep
        return value

class AbsoluteFileEntry(Entry):

    """ Entry field for an absolute OS pathname.

        The pathname will always start with os.sep if given.

    """
    converters = (str,)

    def post_process(self,value,locals,globals):

        if value and value[0] != os.sep:
            value = os.sep + value
        return value

class AbsolutePathEntry(Entry):

    """ Entry field for an absolute OS path.

        The pathname will always start and end with os.sep if given.

    """
    converters = (str,)

    def post_process(self,value,locals,globals):

        if value:
            if value[0] != os.sep:
                value = os.sep + value
            if value[-1] != os.sep:
                value = value + os.sep
        return value

class RelativePathEntry(PathEntry):

    """ Entry field for relative paths.
    
        The path stored is the result of joining the given parameter
        with a basepath. basepath is subject to variable expansion at
        parsing time.
        
    """
    def __init__(self,basepath,default=NotGiven):

        self.basepath = basepath
        PathEntry.__init__(self,default)

    def post_process(self,value,locals,globals):

        return os.path.join(expand_vars(self.basepath,locals,globals),value)

class RelativeFileEntry(FileEntry):

    """ Entry field for relative pathnames to files.
    
        The path stored is the result of joining the given parameter
        with a basepath. basepath is subject to variable expansion at
        parsing time.
        
    """
    def __init__(self,basepath,default=NotGiven):

        self.basepath = basepath
        PathEntry.__init__(self,default)

    def post_process(self,value,locals,globals):

        return os.path.join(expand_vars(self.basepath,locals,globals),value)

class ExistingPathEntry(PathEntry):

    """ Checks value to point to an existing OS path.

        Raises an exception if the path does not exist.
    """
    def post_process(self,value,locals,globals):

        if value and value[-1] != os.sep:
            value = value + os.sep
        if not os.path.exists(value):
            raise Error,'non existing path "%s"' % value
        return value

class ExistingFileEntry(FileEntry):

    """ Checks value to point to an existing file.

        Raises an exception if the file does not exist.
    """
    def post_process(self,value,locals,globals):

        if not value or not os.path.exists(value):
            raise Error,'non existing file "%s"' % value
        return value

class ExistingRelativePathEntry(RelativePathEntry):

    """ Entry field for relative paths.
    
        The path stored is the result of joining the given parameter
        with a basepath.  Raises an exception if the path does not
        exist.
        
    """
    def post_process(self,value,locals,globals):

        value = os.path.join(expand_vars(self.basepath,locals,globals),value)
        if not os.path.exists(value):
            raise Error,'non existing path "%s"' % value
        return value

class URLEntry(StringEntry):

    """ Entry field for URLs.

        The field takes a default value as argument. 

        Needs mxHTMLTools to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx import HTMLTools
        return HTMLTools.URL(value)

class RelativeURLEntry(URLEntry):

    """ Entry field for relative URLs.

        A base URL can be set which is then urljoined with the
        value given. The field also takes a default value.

        Needs mxHTMLTools to be installed.

    """
    def __init__(self,baseurl='',default=NotGiven):

        self.baseurl = baseurl
        StringEntry.__init__(self,default)

    def post_process(self,value,locals,globals):

        from mx import HTMLTools
        return HTMLTools.urljoin(expand_vars(self.baseurl,locals,globals),
                                 value)

class AbsoluteURLEntry(RelativeURLEntry):

    """ Entry field for absolute URLs.

        A base URL can be set which is then urljoined with the
        value given. The field also takes a default value as second
        argument.
    """
    def post_process(self,value,locals,globals):

        url = RelativeURLEntry.post_process(self,value,locals,globals)
        if not url.absolute:
            raise Error,'need an absolute URL: "%s"' % url
        return url

class DateEntry(Entry):

    """ Date entry field.

        The value is stored using a DateTime instance. A time part is
        ignored.

        Needs mxDateTime to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx.DateTime.Parser import DateFromString
        return DateFromString(value)

class DateTimeEntry(Entry):

    """ Date/time entry field.

        The value is stored using a DateTime instance.

        Needs mxDateTime to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx.DateTime.Parser import DateTimeFromString
        return DateTimeFromString(value)

class TimeEntry(Entry):

    """ Time entry field.

        The value is stored using a DateTimeDelta instance. A date
        part is ignored.

        Needs mxDateTime to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx.DateTime.Parser import TimeFromString
        return TimeFromString(value)

class DateTimeDeltaEntry(Entry):

    """ Date/time delta entry field.

        The value is stored using a DateTimeDelta instance.

        Needs mxDateTime to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx.DateTime.Parser import DateTimeDeltaFromString
        return DateTimeDeltaFromString(value)

class RelativeDateTimeEntry(Entry):

    """ Relative date/time entry field.

        The value is stored using a RelativeDateTime instance.

        Needs mxDateTime to be installed.

    """
    def post_process(self,value,locals,globals):

        from mx.DateTime.Parser import RelativeDateTimeFromString
        return RelativeDateTimeFromString(value)

class EvalEntry(Entry):

    """ Allows simple calculations to be done using the
        current locals (the symbols defined in the class
        where the entry is located) and globals.

    """
    def parse(self,text,locals,globals,

              eval=eval):

        self.value = eval(text,locals,globals)
        return self.value
        
class SafeEvalEntry(Entry):

    """ Allows simple calculations to be done using the
        current locals (the symbols defined in the class
        where the entry is located) and globals.

        Builtins are not available.

    """
    def parse(self,text,locals,globals,

              reval=reval):

        self.value = reval(text,locals,globals)
        return self.value
        
class DictEntry(Entry):

    """ Allows the construction of a Python dictionary.

        The entries value is taken as list of key: value pairs which
        are evaluated in the current locals (the symbols defined in
        the class where the entry is located) and globals.

        Parsing is left to the Python interpreter. The needed curly
        brackets {} are added by the parsing method.

        Sample:

        dict = 'a': (1,2,3), 'b': (3,4,5)

    """
    def parse(self,text,locals,globals):

        self.value = eval('{' + text + '}',locals,globals)
        return self.value

### Namespace containers

class ConfigNamespace(Namespace.Namespace):
    
    # This attribute may be set to allow new sections to be
    # created by the ini-file editor. The parser will use this
    # class to instantiate those sections.
    DefaultSection = None

    # This attribute may be set to allow new attributes to be
    # created by the ini-file editor. The parser will use this
    # object as template for the new attributes by deepcopying
    # it.
    DefaultAttribute = None

    def __init__(self,

                 getattr=getattr,
                 skip_types=(types.ModuleType,
                             types.IntType,
                             types.StringType,
                             types.NoneType,
                             ),
                 del_types=(types.FunctionType,
                            types.MethodType,
                            types.BuiltinFunctionType,
                            types.BuiltinMethodType,),
                 deepcopy=copy.deepcopy,ClassType=types.ClassType):

        # Localize class attributes in the instance dict
        classobj = self.__class__
        freeze(classobj)
        dict = self.__dict__
        dict.update(classobj.__dict__)

        # Fixup attributes
        for name,obj in dict.items():

            if name[:1] == '_ ':
                # Delete all special attributes
                del dict[name]
            
            objtype = type(obj)
            
            if objtype is ClassType:
                # Handle classes
                if name != 'DefaultSection' and \
                   issubclass(obj,ConfigSection):
                    # Instantiate ConfigSections
                    dict[name] = obj()
                # leave all others as classes

            elif objtype in del_types:
                # Delete these types
                del dict[name]

            elif objtype in skip_types:
                # Skip these types
                pass

            else:
                # Deepcopy everything else
                try:
                    dict[name] = deepcopy(obj)
                except copy.error,why:
                    raise Error,\
                          'namespace entry "%s" could not be copied: %s' % \
                          (name,why)

    #
    # Dictionary like interface (we hide the internally used attributes)
    #
                
    def _items(self):

        items = []
        append = items.append
        for k,v in self.__dict__.items():
            if k[:1] == '_' or \
               k in ('DefaultSection', 'DefaultAttribute', 'baseobj'):
                continue
            append((k,v))
        return items

    def _keys(self):

        items = []
        append = items.append
        for k,v in self.__dict__.items():
            if k[:1] == '_' or \
               k in ('DefaultSection', 'DefaultAttribute', 'baseobj'):
                continue
            append(k)
        return items

    def _values(self):

        items = []
        append = items.append
        for k,v in self.__dict__.items():
            if k[:1] == '_' or \
               k in ('DefaultSection', 'DefaultAttribute', 'baseobj'):
                continue
            append(v)
        return items

    def _dictionary(self):

        d = {}
        d.update(self.__dict__)
        # Remove internal attributes
        for k in d.keys():
            if k[:1] == '_' or \
               k in ('DefaultSection', 'DefaultAttribute', 'baseobj'):
                del d[k]
        return d

class ConfigSection(ConfigNamespace):
    pass

###

parse_section = re.compile('\[([a-zA-Z_][a-zA-Z_0-9]*)\]')
parse_setattr = re.compile('([a-zA-Z_][a-zA-Z_0-9]*)[ \t]*=[ \t]*(.*)')

class ConfigFile:

    """ Configuration file reader.

        Takes a template (a ConfigNamespace subclass) as input which
        defines sections using classes. Sections may include instances
        of Entry as attributes. These are then used to process the
        file input.

        The template is (deep-)copied and placed into the instance
        variable .data (a ConfigNamespace instance) prior to reading
        the file. Section classes are replaced with ConfigSection
        instances.

        After successful reading the file, the configuration
        information is available through this variable.

        Errors are indicated by exceptions of type Error. These always
        have values (line_number, explanation) where line_number is 0
        for errors which do not refer to one specific line in the
        file.
        
    """
    data = None                         # configuration namespace

    def __init__(self,template):

        self.template = template
        self.reset()

    def reset(self,

              deepcopy=copy.deepcopy,ClassType=types.ClassType,
              ModuleType=types.ModuleType):

        """ Reset the object to its initial state.

            This initializes self.data to a template instance.

        """
        self.data = self.template()

    def read(self,file,

             deepcopy=copy.deepcopy):

        """ Read and parse the open file.

            The configuration is stored in the instance variable
            .data.

        """
        context = {}
        sectionname = ''
        data = self.data                # Configuration object
        section = data                  # Current section object
        globals = data.__dict__         # Global namespace
        locals = globals                # Local namespace
        lineno = 0
        if _debug:
            print 'Reading config file:'
        while 1:
            line = file.readline()
            lineno = lineno + 1
            if not line:
                break
            line = line.strip()
            if not line or line[0] in COMMENT_CHARS:
                # Comment or emtpy line: ignore
                continue

            if _debug:
                print ' read %s' % repr(line)

            # Continuation
            current_lineno = lineno
            while line[-1] == '\\':
                nextline = file.readline()
                lineno = lineno + 1
                if not nextline:
                    # EOF: end of continuation
                    line = line[:-1]
                    break
                nextline = nextline.strip()
                if not nextline:
                    # Empty line: end of continuation
                    line = line[:-1]
                    break
                if nextline[0] == '#':
                    # Comment: ignore
                    continue
                if _debug:
                    print ' read continuation %s' % repr(nextline)
                # Add nextline to line
                line = line[:-1] + nextline

            if _debug:
                print ' processing %s' % repr(line)

            m = parse_section.match(line)
            if m:
                # Start a new section
                sectionname = m.groups()[0]
                section = getattr(data,sectionname,None)
                if section is None:
                    if data.DefaultSection:
                        # Instantiate default section for use as
                        # section object and register in data
                        section = data.DefaultSection()
                        setattr(data,sectionname,section)
                    else:
                        raise Error,(current_lineno,
                                     'unknown section "%s"' % 
                                     sectionname)
                #print 'Switched to section:',sectionname
                locals = section.__dict__
                continue

            m = parse_setattr.match(line)
            if m:
                # Add a new attribute
                name,value = m.groups()
                entry = locals.get(name,None)
                if sectionname:
                    attrname = sectionname + '.' + name
                else:
                    attrname = name
                if entry is None:
                    if section.DefaultAttribute:
                        # Instantiate default attribute for use as
                        # attribute object and register in section
                        entry = deepcopy(section.DefaultAttribute)
                        setattr(section,name,entry)
                    else:
                        raise Error,(current_lineno,
                                     'unknown attribute: "%s"' % attrname)
                if not isinstance(entry, Entry):
                    # Since we replace the parsed entries with their parsed
                    # value any occurance of non-Entry instances point
                    # to a duplicate definition of an entry
                    raise Error,(current_lineno,
                                 'duplicate attribute definition for "%s"' %
                                 attrname)
                try:
                    entry.parse(value,locals,globals)
                except:
                    raise Error,(current_lineno,
                                 'invalid attribute value for "%s" (%s: %s)' %
                                 (attrname,
                                  sys.exc_info()[0],sys.exc_info()[1]))
                # Replace with parsed value
                locals[name] = entry.value
                continue

            # The line doesn't have a valid syntax: ignore it
            if _debug:
                print 'Ignoring invalid config file line %i: %s' % \
                      (current_lineno,
                       repr(line))

        # Check for missing entries and replace with parsed values
        for name,obj in globals.items():

            if isinstance(obj,Entry):
                if obj.value is not NotGiven:
                    globals[name] = obj.value
                else:
                    try:
                        obj.parse(obj.default,locals,globals)
                        globals[name] = obj.value
                    except:
                        raise Error,\
                              (0,
                               'invalid default attribute '
                               'value for global "%s" (%s)' %
                               (name,str(sys.exc_info()[1])))

            elif isinstance(obj,ConfigSection):
                locals = obj.__dict__
                sectionname = name
                for name,obj in locals.items():
                    if isinstance(obj,Entry):
                        if obj.value is not NotGiven:
                            locals[name] = obj.value
                        else:
                            try:
                                obj.parse(obj.default,locals,globals)
                                locals[name] = obj.value
                            except:
                                import traceback; traceback.print_exc()
                                raise Error,\
                                      (0,
                                       'invalid default attribute '
                                       'value for local "%s" (%s)' %
                                       (name,str(sys.exc_info()[1])))


### Test
        
if __name__ == '__main__':

    class Template(ConfigNamespace):

        import sys

        globalvar = IntegerEntry(1)

        # New attributes in the global section are strings
        DefaultAttribute = StringEntry('')

        class ABC(ConfigSection):
            a = IntegerEntry('0')
            b = StringEntry('default.html')
            c = StringEntry()
            d = StringTupleEntry('a,b')
            path = ExistingPathEntry('.')

            # Use this as template for new attributes
            DefaultAttribute = RelativePathEntry('..','')

        class DEF(ConfigSection):
            a = IntegerEntry('0')
            b = EvalEntry('0')
            c = StringEntry('default value')
            d = RelativePathEntry('$ABC.b','HOME')
            g = IntegerEntry('0')
            continuation = CommaTupleEntry('')
            databases = DictEntry('')
            timeout = TimeEntry('0:15:00.23')

        # Default section
        DefaultSection = ABC

    text = """\
    # Luckily we don't have to pay attention to proper indentation
    # or whether strings have quotes or not... the template knows
    # what to do.

    globalvar = 2

    # New global attribute
    test = text

    [ABC]
    a = 1
    b = abc.html
    c = text with spaces
    d = heinz, kunz, philipp
    path = /tmp

    # A new attribute
    new = .cshrc

    [DEF]
    a = 2
    b = a + 3
    c = $PWD
    d = home

    continuation = first line, \\
                   # Comment should not hurt
                   second line, \\

                   # Invalid syntax:
                   third line \\

    databases = 'iODBC': (sys,sys.exit,('c',1,2)), \\
                'Adabas': (sys,sys.exit,('x','y','z'))

    [NewSection]
    a = 3

    """

    import cStringIO

    f = cStringIO.StringIO(text)
    cf = ConfigFile(Template)
    cf.read(f)