This file is indexed.

/usr/lib/python3/dist-packages/apt/debfile.py is in python3-apt 0.9.3.5.

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
#  Copyright (c) 2005-2010 Canonical
#
#  Author: Michael Vogt <michael.vogt@ubuntu.com>
#
#  This program is free software; you can redistribute it and/or
#  modify it under the terms of the GNU General Public License as
#  published by the Free Software Foundation; either version 2 of the
#  License, or (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
#  USA
"""Classes for working with locally available Debian packages."""
from __future__ import print_function

import apt
import apt_inst
import apt_pkg
import gzip
import os
import sys

from apt_pkg import gettext as _
from io import StringIO


class NoDebArchiveException(IOError):
    """Exception which is raised if a file is no Debian archive."""


class DebPackage(object):
    """A Debian Package (.deb file)."""

    # Constants for comparing the local package file with the version
    # in the cache
    (VERSION_NONE,
     VERSION_OUTDATED,
     VERSION_SAME,
     VERSION_NEWER) = range(4)

    debug = 0

    def __init__(self, filename=None, cache=None):
        if cache is None:
            cache = apt.Cache()
        self._cache = cache
        self._debfile = None
        self.pkgname = ""
        self._sections = {}
        self._need_pkgs = []
        self._check_was_run = False
        self._failure_string = ""
        self._multiarch = None
        if filename:
            self.open(filename)

    def open(self, filename):
        """ open given debfile """
        self._dbg(3, "open '%s'" % filename)
        self._need_pkgs = []
        self._installed_conflicts = set()
        self._failure_string = ""
        self.filename = filename
        self._debfile = apt_inst.DebFile(self.filename)
        control = self._debfile.control.extractdata("control")
        self._sections = apt_pkg.TagSection(control)
        self.pkgname = self._sections["Package"]
        self._check_was_run = False

    def __getitem__(self, key):
        return self._sections[key]

    def __contains__(self, key):
        return key in self._sections

    @property
    def filelist(self):
        """return the list of files in the deb."""
        files = []
        try:
            self._debfile.data.go(lambda item, data: files.append(item.name))
        except SystemError:
            return [_("List of files for '%s' could not be read") %
                    self.filename]
        return files

    @property
    def control_filelist(self):
        """ return the list of files in control.tar.gt """
        control = []
        try:
            self._debfile.control.go(
                lambda item, data: control.append(item.name))
        except SystemError:
            return [_("List of control files for '%s' could not be read") %
                    self.filename]
        return sorted(control)

    # helper that will return a pkgname with a multiarch suffix if needed
    def _maybe_append_multiarch_suffix(self, pkgname,
                                       in_conflict_checking=False):
        # trivial cases
        if ":" in pkgname:
            return pkgname
        if not self._multiarch:
            return pkgname
        elif self._cache.is_virtual_package(pkgname):
            return pkgname
        elif (pkgname in self._cache and
              self._cache[pkgname].candidate and
              self._cache[pkgname].candidate.architecture == "all"):
            return pkgname
        # now do the real multiarch checking
        multiarch_pkgname = "%s:%s" % (pkgname, self._multiarch)
        # the upper layers will handle this
        if not multiarch_pkgname in self._cache:
            return multiarch_pkgname
        # now check the multiarch state
        cand = self._cache[multiarch_pkgname].candidate._cand
        #print pkgname, multiarch_pkgname, cand.multi_arch
        # the default is to add the suffix, unless its a pkg that can satify
        # foreign dependencies
        if cand.multi_arch & cand.MULTI_ARCH_FOREIGN:
            return pkgname
        # for conflicts we need a special case here, any not multiarch enabled
        # package has a implicit conflict
        if (in_conflict_checking and
            not (cand.multi_arch & cand.MULTI_ARCH_SAME)):
            return pkgname
        return multiarch_pkgname

    def _is_or_group_satisfied(self, or_group):
        """Return True if at least one dependency of the or-group is satisfied.

        This method gets an 'or_group' and analyzes if at least one dependency
        of this group is already satisfied.
        """
        self._dbg(2, "_checkOrGroup(): %s " % (or_group))

        for dep in or_group:
            depname = dep[0]
            ver = dep[1]
            oper = dep[2]

            # multiarch
            depname = self._maybe_append_multiarch_suffix(depname)

            # check for virtual pkgs
            if not depname in self._cache:
                if self._cache.is_virtual_package(depname):
                    self._dbg(
                        3, "_is_or_group_satisfied(): %s is virtual dep" %
                        depname)
                    for pkg in self._cache.get_providing_packages(depname):
                        if pkg.is_installed:
                            return True
                continue
            # check real dependency
            inst = self._cache[depname].installed
            if inst is not None and apt_pkg.check_dep(inst.version, oper, ver):
                return True

            # if no real dependency is installed, check if there is
            # a package installed that provides this dependency
            # (e.g. scrollkeeper dependecies are provided by rarian-compat)
            # but only do that if there is no version required in the
            # dependency (we do not supprot versionized dependencies)
            if not oper:
                for ppkg in self._cache.get_providing_packages(
                    depname, include_nonvirtual=True):
                    if ppkg.is_installed:
                        self._dbg(
                            3, "found installed '%s' that provides '%s'" % (
                                ppkg.name, depname))
                        return True
        return False

    def _satisfy_or_group(self, or_group):
        """Try to satisfy the or_group."""
        for dep in or_group:
            depname, ver, oper = dep

            # multiarch
            depname = self._maybe_append_multiarch_suffix(depname)

            # if we don't have it in the cache, it may be virtual
            if not depname in self._cache:
                if not self._cache.is_virtual_package(depname):
                    continue
                providers = self._cache.get_providing_packages(depname)
                # if a package just has a single virtual provider, we
                # just pick that (just like apt)
                if len(providers) != 1:
                    continue
                depname = providers[0].name

            # now check if we can satisfy the deps with the candidate(s)
            # in the cache
            pkg = self._cache[depname]
            cand = self._cache._depcache.get_candidate_ver(pkg._pkg)
            if not cand:
                continue
            if not apt_pkg.check_dep(cand.ver_str, oper, ver):
                continue

            # check if we need to install it
            self._dbg(2, "Need to get: %s" % depname)
            self._need_pkgs.append(depname)
            return True

        # if we reach this point, we failed
        or_str = ""
        for dep in or_group:
            or_str += dep[0]
            if ver and oper:
                or_str += " (%s %s)" % (dep[2], dep[1])
            if dep != or_group[len(or_group) - 1]:
                or_str += "|"
        self._failure_string += _(
            "Dependency is not satisfiable: %s\n") % or_str
        return False

    def _check_single_pkg_conflict(self, pkgname, ver, oper):
        """Return True if a pkg conflicts with a real installed/marked pkg."""
        # FIXME: deal with conflicts against its own provides
        #        (e.g. Provides: ftp-server, Conflicts: ftp-server)
        self._dbg(
            3, "_check_single_pkg_conflict() pkg='%s' ver='%s' oper='%s'" % (
                pkgname, ver, oper))
        pkg = self._cache[pkgname]
        if pkg.is_installed:
            pkgver = pkg.installed.version
        elif pkg.marked_install:
            pkgver = pkg.candidate.version
        else:
            return False
        #print "pkg: %s" % pkgname
        #print "ver: %s" % ver
        #print "pkgver: %s " % pkgver
        #print "oper: %s " % oper
        if (apt_pkg.check_dep(pkgver, oper, ver) and not
            self.replaces_real_pkg(pkgname, oper, ver)):
            self._failure_string += _("Conflicts with the installed package "
                                      "'%s'") % pkg.name
            self._dbg(3, "conflicts with installed pkg '%s'" % pkg.name)
            return True
        return False

    def _check_conflicts_or_group(self, or_group):
        """Check the or-group for conflicts with installed pkgs."""
        self._dbg(2, "_check_conflicts_or_group(): %s " % (or_group))
        for dep in or_group:
            depname = dep[0]
            ver = dep[1]
            oper = dep[2]

            # FIXME: is this good enough? i.e. will apt always populate
            #        the cache with conflicting pkgnames for our arch?
            depname = self._maybe_append_multiarch_suffix(
                depname, in_conflict_checking=True)

            # check conflicts with virtual pkgs
            if not depname in self._cache:
                # FIXME: we have to check for virtual replaces here as
                #        well (to pass tests/gdebi-test8.deb)
                if self._cache.is_virtual_package(depname):
                    for pkg in self._cache.get_providing_packages(depname):
                        self._dbg(3, "conflicts virtual check: %s" % pkg.name)
                        # P/C/R on virtal pkg, e.g. ftpd
                        if self.pkgname == pkg.name:
                            self._dbg(3, "conflict on self, ignoring")
                            continue
                        if self._check_single_pkg_conflict(
                                pkg.name, ver, oper):
                            self._installed_conflicts.add(pkg.name)
                continue
            if self._check_single_pkg_conflict(depname, ver, oper):
                self._installed_conflicts.add(depname)
        return bool(self._installed_conflicts)

    @property
    def conflicts(self):
        """List of package names conflicting with this package."""
        key = "Conflicts"
        try:
            return apt_pkg.parse_depends(self._sections[key], False)
        except KeyError:
            return []

    @property
    def depends(self):
        """List of package names on which this package depends on."""
        depends = []
        # find depends
        for key in "Depends", "Pre-Depends":
            try:
                depends.extend(
                    apt_pkg.parse_depends(self._sections[key], False))
            except KeyError:
                pass
        return depends

    @property
    def provides(self):
        """List of virtual packages which are provided by this package."""
        key = "Provides"
        try:
            return apt_pkg.parse_depends(self._sections[key], False)
        except KeyError:
            return []

    @property
    def replaces(self):
        """List of packages which are replaced by this package."""
        key = "Replaces"
        try:
            return apt_pkg.parse_depends(self._sections[key], False)
        except KeyError:
            return []

    def replaces_real_pkg(self, pkgname, oper, ver):
        """Return True if a given non-virtual package is replaced.

        Return True if the deb packages replaces a real (not virtual)
        packages named (pkgname, oper, ver).
        """
        self._dbg(3, "replaces_real_pkg() %s %s %s" % (pkgname, oper, ver))
        pkg = self._cache[pkgname]
        if pkg.is_installed:
            pkgver = pkg.installed.version
        elif pkg.marked_install:
            pkgver = pkg.candidate.version
        else:
            pkgver = None
        for or_group in self.replaces:
            for (name, ver, oper) in or_group:
                if (name == pkgname and apt_pkg.check_dep(pkgver, oper, ver)):
                    self._dbg(3, "we have a replaces in our package for the "
                                 "conflict against '%s'" % (pkgname))
                    return True
        return False

    def check_conflicts(self):
        """Check if there are conflicts with existing or selected packages.

        Check if the package conflicts with a existing or to be installed
        package. Return True if the pkg is OK.
        """
        res = True
        for or_group in self.conflicts:
            if self._check_conflicts_or_group(or_group):
                #print "Conflicts with a exisiting pkg!"
                #self._failure_string = "Conflicts with a exisiting pkg!"
                res = False
        return res

    def check_breaks_existing_packages(self):
        """
        check if installing the package would break exsisting
        package on the system, e.g. system has:
        smc depends on smc-data (= 1.4)
        and user tries to installs smc-data 1.6
        """
        # show progress information as this step may take some time
        size = float(len(self._cache))
        steps = max(int(size / 50), 1)
        debver = self._sections["Version"]
        debarch = self._sections["Architecture"]
        # store what we provide so that we can later check against that
        provides = [x[0][0] for x in self.provides]
        for (i, pkg) in enumerate(self._cache):
            if i % steps == 0:
                self._cache.op_progress.update(float(i) / size * 100.0)
            if not pkg.is_installed:
                continue
            # check if the exising dependencies are still satisfied
            # with the package
            ver = pkg._pkg.current_ver
            for dep_or in pkg.installed.dependencies:
                for dep in dep_or.or_dependencies:
                    if dep.name == self.pkgname:
                        if not apt_pkg.check_dep(
                                debver, dep.relation, dep.version):
                            self._dbg(2, "would break (depends) %s" % pkg.name)
                            # TRANSLATORS: the first '%s' is the package that
                            # breaks, the second the dependency that makes it
                            # break, the third the relation (e.g. >=) and the
                            # latest the version for the releation
                            self._failure_string += _(
                                "Breaks existing package '%(pkgname)s' "
                                "dependency %(depname)s "
                                "(%(deprelation)s %(depversion)s)") % {
                                    'pkgname': pkg.name,
                                    'depname': dep.name,
                                    'deprelation': dep.relation,
                                    'depversion': dep.version}
                            self._cache.op_progress.done()
                            return False
            # now check if there are conflicts against this package on
            # the existing system
            if "Conflicts" in ver.depends_list:
                for conflicts_ver_list in ver.depends_list["Conflicts"]:
                    for c_or in conflicts_ver_list:
                        if (c_or.target_pkg.name == self.pkgname and
                                c_or.target_pkg.architecture == debarch):
                            if apt_pkg.check_dep(
                                    debver, c_or.comp_type, c_or.target_ver):
                                self._dbg(
                                    2, "would break (conflicts) %s" % pkg.name)
                                # TRANSLATORS: the first '%s' is the package
                                # that conflicts, the second the packagename
                                # that it conflicts with (so the name of the
                                # deb the user tries to install), the third is
                                # the relation (e.g. >=) and the last is the
                                # version for the relation
                                self._failure_string += _(
                                    "Breaks existing package '%(pkgname)s' "
                                    "conflict: %(targetpkg)s "
                                    "(%(comptype)s %(targetver)s)") % {
                                        'pkgname': pkg.name,
                                        'targetpkg': c_or.target_pkg.name,
                                        'comptype': c_or.comp_type,
                                        'targetver': c_or.target_ver}
                                self._cache.op_progress.done()
                                return False
                        if (c_or.target_pkg.name in provides and
                            self.pkgname != pkg.name):
                            self._dbg(
                                2, "would break (conflicts) %s" % provides)
                            self._failure_string += _(
                                "Breaks existing package '%(pkgname)s' "
                                "that conflict: '%(targetpkg)s'. But the "
                                "'%(debfile)s' provides it via: "
                                "'%(provides)s'") % {
                                    'provides': ",".join(provides),
                                    'debfile': self.filename,
                                    'targetpkg': c_or.target_pkg.name,
                                    'pkgname': pkg.name}
                            self._cache.op_progress.done()
                            return False
        self._cache.op_progress.done()
        return True

    def compare_to_version_in_cache(self, use_installed=True):
        """Compare the package to the version available in the cache.

        Checks if the package is already installed or availabe in the cache
        and if so in what version, returns one of (VERSION_NONE,
        VERSION_OUTDATED, VERSION_SAME, VERSION_NEWER).
        """
        self._dbg(3, "compare_to_version_in_cache")
        pkgname = self._sections["Package"]
        debver = self._sections["Version"]
        self._dbg(1, "debver: %s" % debver)
        if pkgname in self._cache:
            if use_installed and self._cache[pkgname].installed:
                cachever = self._cache[pkgname].installed.version
            elif not use_installed and self._cache[pkgname].candidate:
                cachever = self._cache[pkgname].candidate.version
            else:
                return self.VERSION_NONE
            if cachever is not None:
                cmp = apt_pkg.version_compare(cachever, debver)
                self._dbg(1, "CompareVersion(debver,instver): %s" % cmp)
                if cmp == 0:
                    return self.VERSION_SAME
                elif cmp < 0:
                    return self.VERSION_NEWER
                elif cmp > 0:
                    return self.VERSION_OUTDATED
        return self.VERSION_NONE

    def check(self):
        """Check if the package is installable."""
        self._dbg(3, "check")

        self._check_was_run = True

        # check arch
        if not "Architecture" in self._sections:
            self._dbg(1, "ERROR: no architecture field")
            self._failure_string = _("No Architecture field in the package")
            return False
        arch = self._sections["Architecture"]
        if arch != "all" and arch != apt_pkg.config.find("APT::Architecture"):
            if arch in apt_pkg.get_architectures():
                self._multiarch = arch
                self.pkgname = "%s:%s" % (self.pkgname, self._multiarch)
                self._dbg(1, "Found multiarch arch: '%s'" % arch)
            else:
                self._dbg(1, "ERROR: Wrong architecture dude!")
                self._failure_string = _("Wrong architecture '%s'") % arch
                return False

        # check version
        if self.compare_to_version_in_cache() == self.VERSION_OUTDATED:
            if self._cache[self.pkgname].installed:
                # the deb is older than the installed
                self._failure_string = _(
                    "A later version is already installed")
                return False

        # FIXME: this sort of error handling sux
        self._failure_string = ""

        # check conflicts
        if not self.check_conflicts():
            return False

        # check if installing it would break anything on the
        # current system
        if not self.check_breaks_existing_packages():
            return False

        # try to satisfy the dependencies
        if not self._satisfy_depends(self.depends):
            return False

        # check for conflicts again (this time with the packages that are
        # makeed for install)
        if not self.check_conflicts():
            return False

        if self._cache._depcache.broken_count > 0:
            self._failure_string = _("Failed to satisfy all dependencies "
                                     "(broken cache)")
            # clean the cache again
            self._cache.clear()
            return False
        return True

    def satisfy_depends_str(self, dependsstr):
        """Satisfy the dependencies in the given string."""
        return self._satisfy_depends(apt_pkg.parse_depends(dependsstr, False))

    def _satisfy_depends(self, depends):
        """Satisfy the dependencies."""
        # turn off MarkAndSweep via a action group (if available)
        try:
            _actiongroup = apt_pkg.ActionGroup(self._cache._depcache)
            _actiongroup  # pyflakes
        except AttributeError:
            pass
        # check depends
        for or_group in depends:
            if not self._is_or_group_satisfied(or_group):
                if not self._satisfy_or_group(or_group):
                    return False
        # now try it out in the cache
        for pkg in self._need_pkgs:
            try:
                self._cache[pkg].mark_install(from_user=False)
            except SystemError:
                self._failure_string = _("Cannot install '%s'") % pkg
                self._cache.clear()
                return False
        return True

    @property
    def missing_deps(self):
        """Return missing dependencies."""
        self._dbg(1, "Installing: %s" % self._need_pkgs)
        if not self._check_was_run:
            raise AttributeError(
                "property only available after check() was run")
        return self._need_pkgs

    @property
    def required_changes(self):
        """Get the changes required to satisfy the dependencies.

        Returns: a tuple with (install, remove, unauthenticated)
        """
        install = []
        remove = []
        unauthenticated = []
        if not self._check_was_run:
            raise AttributeError(
                "property only available after check() was run")
        for pkg in self._cache:
            if pkg.marked_install or pkg.marked_upgrade:
                install.append(pkg.name)
                # check authentication, one authenticated origin is enough
                # libapt will skip non-authenticated origins then
                authenticated = False
                for origin in pkg.candidate.origins:
                    authenticated |= origin.trusted
                if not authenticated:
                    unauthenticated.append(pkg.name)
            if pkg.marked_delete:
                remove.append(pkg.name)
        return (install, remove, unauthenticated)

    @staticmethod
    def to_hex(in_data):
        hex = ""
        for (i, c) in enumerate(in_data):
            if i % 80 == 0:
                hex += "\n"
            hex += "%2.2x " % ord(c)
        return hex

    @staticmethod
    def to_strish(in_data):
        s = ""
        # py2 compat, in_data is type string
        if type(in_data) == str:
            for c in in_data:
                if ord(c) < 10 or ord(c) > 127:
                    s += " "
                else:
                    s += c
        # py3 compat, in_data is type bytes
        else:
            for b in in_data:
                if b < 10 or b > 127:
                    s += " "
                else:
                    s += chr(b)
        return s

    def _get_content(self, part, name, auto_decompress=True, auto_hex=True):
        if name.startswith("./"):
            name = name[2:]
        data = part.extractdata(name)
        # check for zip content
        if name.endswith(".gz") and auto_decompress:
            io = StringIO(data)
            gz = gzip.GzipFile(fileobj=io)
            data = _("Automatically decompressed:\n\n")
            data += gz.read()
        # auto-convert to hex
        try:
            data = data.decode("utf-8")
        except Exception:
            new_data = _("Automatically converted to printable ascii:\n")
            new_data += self.to_strish(data)
            return new_data
        return data

    def control_content(self, name):
        """ return the content of a specific control.tar.gz file """
        try:
            return self._get_content(self._debfile.control, name)
        except LookupError:
            return ""

    def data_content(self, name):
        """ return the content of a specific control.tar.gz file """
        try:
            return self._get_content(self._debfile.data, name)
        except LookupError:
            return ""

    def _dbg(self, level, msg):
        """Write debugging output to sys.stderr."""
        if level <= self.debug:
            print(msg, file=sys.stderr)

    def install(self, install_progress=None):
        """Install the package."""
        if install_progress is None:
            return os.spawnlp(os.P_WAIT, "dpkg", "dpkg", "-i", self.filename)
        else:
            try:
                install_progress.start_update()
            except AttributeError:
                install_progress.startUpdate()
            res = install_progress.run(self.filename)
            try:
                install_progress.finish_update()
            except AttributeError:
                install_progress.finishUpdate()
            return res


class DscSrcPackage(DebPackage):
    """A locally available source package."""

    def __init__(self, filename=None, cache=None):
        DebPackage.__init__(self, None, cache)
        self.filename = filename
        self._depends = []
        self._conflicts = []
        self._installed_conflicts = set()
        self.pkgname = ""
        self.binaries = []
        if self.filename is not None:
            self.open(self.filename)

    @property
    def depends(self):
        """Return the dependencies of the package"""
        return self._depends

    @property
    def conflicts(self):
        """Return the dependencies of the package"""
        return self._conflicts

    def open(self, file):
        """Open the package."""
        depends_tags = ["Build-Depends", "Build-Depends-Indep"]
        conflicts_tags = ["Build-Conflicts", "Build-Conflicts-Indep"]
        fobj = open(file)
        tagfile = apt_pkg.TagFile(fobj)
        try:
            for sec in tagfile:
                for tag in depends_tags:
                    if not tag in sec:
                        continue
                    self._depends.extend(apt_pkg.parse_src_depends(sec[tag]))
                for tag in conflicts_tags:
                    if not tag in sec:
                        continue
                    self._conflicts.extend(apt_pkg.parse_src_depends(sec[tag]))
                if 'Source' in sec:
                    self.pkgname = sec['Source']
                if 'Binary' in sec:
                    self.binaries = sec['Binary'].split(', ')
                if 'Version' in sec:
                    self._sections['Version'] = sec['Version']
        finally:
            del tagfile
            fobj.close()

        s = _("Install Build-Dependencies for "
              "source package '%s' that builds %s\n") % (self.pkgname,
              " ".join(self.binaries))
        self._sections["Description"] = s
        self._check_was_run = False

    def check(self):
        """Check if the package is installable.."""
        if not self.check_conflicts():
            for pkgname in self._installed_conflicts:
                if self._cache[pkgname]._pkg.essential:
                    raise Exception(_("An essential package would be removed"))
                self._cache[pkgname].mark_delete()
        # properties are ok now
        self._check_was_run = True
        # FIXME: a additional run of the check_conflicts()
        #        after _satisfy_depends() should probably be done
        return self._satisfy_depends(self.depends)


def _test():
    """Test function"""
    from apt.cache import Cache
    from apt.progress.base import InstallProgress

    cache = Cache()

    vp = "www-browser"
    print("%s virtual: %s" % (vp, cache.is_virtual_package(vp)))
    providers = cache.get_providing_packages(vp)
    print("Providers for %s :" % vp)
    for pkg in providers:
        print(" %s" % pkg.name)

    d = DebPackage(sys.argv[1], cache)
    print("Deb: %s" % d.pkgname)
    if not d.check():
        print("can't be satified")
        print(d._failure_string)
    print("missing deps: %s" % d.missing_deps)
    print(d.required_changes)

    print(d.filelist)

    print("Installing ...")
    ret = d.install(InstallProgress())
    print(ret)

    #s = DscSrcPackage(cache, "../tests/3ddesktop_0.2.9-6.dsc")
    #s.check_dep()
    #print "Missing deps: ",s.missingDeps
    #print "Print required changes: ", s.requiredChanges

    s = DscSrcPackage(cache=cache)
    d = "libc6 (>= 2.3.2), libaio (>= 0.3.96) | libaio1 (>= 0.3.96)"
    print(s._satisfy_depends(apt_pkg.parse_depends(d, False)))

if __name__ == "__main__":
    _test()