zeroinstall/injector/model.py

   1 """In-memory representation of interfaces and other data structures.
   2
   3 The objects in this module are used to build a representation of an XML interface
   4 file in memory.
   5
   6 @see: L{reader} constructs these data-structures
   7 @see: U{http://0install.net/interface-spec.html} description of the domain model
   8
   9 @var defaults: Default values for the 'default' attribute for <environment> bindings of
  10 well-known variables.
  11 """
  12
  13 # Copyright (C) 2009, Thomas Leonard
  14 # See the README file for details, or visit http://0install.net.
  15
  16 from zeroinstall import _
  17 import os, re, locale
  18 from logging import info, debug, warn
  19 from zeroinstall import SafeException, version
  20 from zeroinstall.injector.namespaces import XMLNS_IFACE
  21 from zeroinstall.injector import qdom
  22
  23 # Element names for bindings in feed files
  24 binding_names = frozenset(['environment', 'overlay'])
  25
  26 network_offline = 'off-line'
  27 network_minimal = 'minimal'
  28 network_full = 'full'
  29 network_levels = (network_offline, network_minimal, network_full)
  30
  31 stability_levels = {}   # Name -> Stability
  32
  33 defaults = {
  34         'PATH': '/bin:/usr/bin',
  35         'XDG_CONFIG_DIRS': '/etc/xdg',
  36         'XDG_DATA_DIRS': '/usr/local/share:/usr/share',
  37 }
  38
  39 class InvalidInterface(SafeException):
  40         """Raised when parsing an invalid feed."""
  41         feed_url = None
  42
  43         def __init__(self, message, ex = None):
  44                 if ex:
  45                         try:
  46                                 message += "\n\n(exact error: %s)" % ex
  47                         except:
  48                                 # Some Python messages have type str but contain UTF-8 sequences.
  49                                 # (e.g. IOException). Adding these to a Unicode 'message' (e.g.
  50                                 # after gettext translation) will cause an error.
  51                                 import codecs
  52                                 decoder = codecs.lookup('utf-8')
  53                                 decex = decoder.decode(str(ex), errors = 'replace')[0]
  54                                 message += "\n\n(exact error: %s)" % decex
  55
  56                 SafeException.__init__(self, message)
  57
  58         def __unicode__(self):
  59                 if hasattr(SafeException, '__unicode__'):
  60                         # Python >= 2.6
  61                         if self.feed_url:
  62                                 return _('%s [%s]') % (SafeException.__unicode__(self), self.feed_url)
  63                         return SafeException.__unicode__(self)
  64                 else:
  65                         return unicode(SafeException.__str__(self))
  66
  67 def _split_arch(arch):
  68         """Split an arch into an (os, machine) tuple. Either or both parts may be None."""
  69         if not arch:
  70                 return None, None
  71         elif '-' not in arch:
  72                 raise SafeException(_("Malformed arch '%s'") % arch)
  73         else:
  74                 osys, machine = arch.split('-', 1)
  75                 if osys == '*': osys = None
  76                 if machine == '*': machine = None
  77                 return osys, machine
  78
  79 def _join_arch(osys, machine):
  80         if osys == machine == None: return None
  81         return "%s-%s" % (osys or '*', machine or '*')
  82
  83 def _best_language_match(options):
  84         (language, encoding) = locale.getlocale()
  85
  86         if language:
  87                 # xml:lang uses '-', while LANG uses '_'
  88                 language = language.replace('_', '-')
  89         else:
  90                 language = 'en-US'
  91
  92         return (options.get(language, None) or                  # Exact match (language+region)
  93                 options.get(language.split('-', 1)[0], None) or # Matching language
  94                 options.get('en', None))                        # English
  95
  96 class Stability(object):
  97         """A stability rating. Each implementation has an upstream stability rating and,
  98         optionally, a user-set rating."""
  99         __slots__ = ['level', 'name', 'description']
 100         def __init__(self, level, name, description):
 101                 self.level = level
 102                 self.name = name
 103                 self.description = description
 104                 assert name not in stability_levels
 105                 stability_levels[name] = self
 106
 107         def __cmp__(self, other):
 108                 return cmp(self.level, other.level)
 109
 110         def __str__(self):
 111                 return self.name
 112
 113         def __repr__(self):
 114                 return _("<Stability: %s>") % self.description
 115
 116 def process_binding(e):
 117         """Internal"""
 118         if e.name == 'environment':
 119                 mode = {
 120                         None: EnvironmentBinding.PREPEND,
 121                         'prepend': EnvironmentBinding.PREPEND,
 122                         'append': EnvironmentBinding.APPEND,
 123                         'replace': EnvironmentBinding.REPLACE,
 124                 }[e.getAttribute('mode')]
 125
 126                 binding = EnvironmentBinding(e.getAttribute('name'),
 127                                              insert = e.getAttribute('insert'),
 128                                              default = e.getAttribute('default'),
 129                                              value = e.getAttribute('value'),
 130                                              mode = mode)
 131                 if not binding.name: raise InvalidInterface(_("Missing 'name' in binding"))
 132                 if binding.insert is None and binding.value is None:
 133                         raise InvalidInterface(_("Missing 'insert' or 'value' in binding"))
 134                 if binding.insert is not None and binding.value is not None:
 135                         raise InvalidInterface(_("Binding contains both 'insert' and 'value'"))
 136                 return binding
 137         elif e.name == 'overlay':
 138                 return OverlayBinding(e.getAttribute('src'), e.getAttribute('mount-point'))
 139         else:
 140                 raise Exception(_("Unknown binding type '%s'") % e.name)
 141
 142 def process_depends(item, local_feed_dir):
 143         """Internal"""
 144         # Note: also called from selections
 145         attrs = item.attrs
 146         dep_iface = item.getAttribute('interface')
 147         if not dep_iface:
 148                 raise InvalidInterface(_("Missing 'interface' on <%s>") % item.name)
 149         if dep_iface.startswith('./'):
 150                 if local_feed_dir:
 151                         dep_iface = os.path.abspath(os.path.join(local_feed_dir, dep_iface))
 152                         # (updates the element too, in case we write it out again)
 153                         attrs['interface'] = dep_iface
 154                 else:
 155                         raise InvalidInterface(_('Relative interface URI "%s" in non-local feed') % dep_iface)
 156         dependency = InterfaceDependency(dep_iface, element = item)
 157
 158         for e in item.childNodes:
 159                 if e.uri != XMLNS_IFACE: continue
 160                 if e.name in binding_names:
 161                         dependency.bindings.append(process_binding(e))
 162                 elif e.name == 'version':
 163                         dependency.restrictions.append(
 164                                 VersionRangeRestriction(not_before = parse_version(e.getAttribute('not-before')),
 165                                                         before = parse_version(e.getAttribute('before'))))
 166         return dependency
 167
 168 def N_(message): return message
 169
 170 insecure = Stability(0, N_('insecure'), _('This is a security risk'))
 171 buggy = Stability(5, N_('buggy'), _('Known to have serious bugs'))
 172 developer = Stability(10, N_('developer'), _('Work-in-progress - bugs likely'))
 173 testing = Stability(20, N_('testing'), _('Stability unknown - please test!'))
 174 stable = Stability(30, N_('stable'), _('Tested - no serious problems found'))
 175 packaged = Stability(35, N_('packaged'), _('Supplied by the local package manager'))
 176 preferred = Stability(40, N_('preferred'), _('Best of all - must be set manually'))
 177
 178 del N_
 179
 180 class Restriction(object):
 181         """A Restriction limits the allowed implementations of an Interface."""
 182         __slots__ = []
 183
 184         def meets_restriction(self, impl):
 185                 """Called by the L{solver.Solver} to check whether a particular implementation is acceptable.
 186                 @return: False if this implementation is not a possibility
 187                 @rtype: bool
 188                 """
 189                 raise NotImplementedError(_("Abstract"))
 190
 191 class VersionRestriction(Restriction):
 192         """Only select implementations with a particular version number.
 193         @since: 0.40"""
 194
 195         def __init__(self, version):
 196                 """@param version: the required version number
 197                 @see: L{parse_version}; use this to pre-process the version number
 198                 """
 199                 self.version = version
 200
 201         def meets_restriction(self, impl):
 202                 return impl.version == self.version
 203
 204         def __str__(self):
 205                 return _("(restriction: version = %s)") % format_version(self.version)
 206
 207 class VersionRangeRestriction(Restriction):
 208         """Only versions within the given range are acceptable"""
 209         __slots__ = ['before', 'not_before']
 210
 211         def __init__(self, before, not_before):
 212                 """@param before: chosen versions must be earlier than this
 213                 @param not_before: versions must be at least this high
 214                 @see: L{parse_version}; use this to pre-process the versions
 215                 """
 216                 self.before = before
 217                 self.not_before = not_before
 218
 219         def meets_restriction(self, impl):
 220                 if self.not_before and impl.version < self.not_before:
 221                         return False
 222                 if self.before and impl.version >= self.before:
 223                         return False
 224                 return True
 225
 226         def __str__(self):
 227                 if self.not_before is not None or self.before is not None:
 228                         range = ''
 229                         if self.not_before is not None:
 230                                 range += format_version(self.not_before) + ' <= '
 231                         range += 'version'
 232                         if self.before is not None:
 233                                 range += ' < ' + format_version(self.before)
 234                 else:
 235                         range = 'none'
 236                 return _("(restriction: %s)") % range
 237
 238 class Binding(object):
 239         """Information about how the choice of a Dependency is made known
 240         to the application being run."""
 241
 242 class EnvironmentBinding(Binding):
 243         """Indicate the chosen implementation using an environment variable."""
 244         __slots__ = ['name', 'insert', 'default', 'mode', 'value']
 245
 246         PREPEND = 'prepend'
 247         APPEND = 'append'
 248         REPLACE = 'replace'
 249
 250         def __init__(self, name, insert, default = None, mode = PREPEND, value=None):
 251                 """
 252                 mode argument added in version 0.28
 253                 value argument added in version 0.52
 254                 """
 255                 self.name = name
 256                 self.insert = insert
 257                 self.default = default
 258                 self.mode = mode
 259                 self.value = value
 260
 261         def __str__(self):
 262                 return _("<environ %(name)s %(mode)s %(insert)s %(value)s>") % {'name': self.name,'mode':  self.mode, 'insert': self.insert, 'value': self.value}
 263
 264         __repr__ = __str__
 265
 266         def get_value(self, path, old_value):
 267                 """Calculate the new value of the environment variable after applying this binding.
 268                 @param path: the path to the selected implementation
 269                 @param old_value: the current value of the environment variable
 270                 @return: the new value for the environment variable"""
 271
 272                 if self.insert is not None:
 273                         extra = os.path.join(path, self.insert)
 274                 else:
 275                         assert self.value is not None
 276                         extra = self.value
 277
 278                 if self.mode == EnvironmentBinding.REPLACE:
 279                         return extra
 280
 281                 if old_value is None:
 282                         old_value = self.default or defaults.get(self.name, None)
 283                 if old_value is None:
 284                         return extra
 285                 if self.mode == EnvironmentBinding.PREPEND:
 286                         return extra + os.pathsep + old_value
 287                 else:
 288                         return old_value + os.pathsep + extra
 289
 290         def _toxml(self, doc):
 291                 """Create a DOM element for this binding.
 292                 @param doc: document to use to create the element
 293                 @return: the new element
 294                 """
 295                 env_elem = doc.createElementNS(XMLNS_IFACE, 'environment')
 296                 env_elem.setAttributeNS(None, 'name', self.name)
 297                 if self.insert is not None:
 298                         env_elem.setAttributeNS(None, 'insert', self.insert)
 299                 else:
 300                         env_elem.setAttributeNS(None, 'value', self.value)
 301                 if self.default:
 302                         env_elem.setAttributeNS(None, 'default', self.default)
 303                 return env_elem
 304
 305 class OverlayBinding(Binding):
 306         """Make the chosen implementation available by overlaying it onto another part of the file-system.
 307         This is to support legacy programs which use hard-coded paths."""
 308         __slots__ = ['src', 'mount_point']
 309
 310         def __init__(self, src, mount_point):
 311                 self.src = src
 312                 self.mount_point = mount_point
 313
 314         def __str__(self):
 315                 return _("<overlay %(src)s on %(mount_point)s>") % {'src': self.src or '.', 'mount_point': self.mount_point or '/'}
 316
 317         __repr__ = __str__
 318
 319         def _toxml(self, doc):
 320                 """Create a DOM element for this binding.
 321                 @param doc: document to use to create the element
 322                 @return: the new element
 323                 """
 324                 env_elem = doc.createElementNS(XMLNS_IFACE, 'overlay')
 325                 if self.src is not None:
 326                         env_elem.setAttributeNS(None, 'src', self.src)
 327                 if self.mount_point is not None:
 328                         env_elem.setAttributeNS(None, 'mount-point', self.mount_point)
 329                 return env_elem
 330
 331 class Feed(object):
 332         """An interface's feeds are other interfaces whose implementations can also be
 333         used as implementations of this interface."""
 334         __slots__ = ['uri', 'os', 'machine', 'user_override', 'langs']
 335         def __init__(self, uri, arch, user_override, langs = None):
 336                 self.uri = uri
 337                 # This indicates whether the feed comes from the user's overrides
 338                 # file. If true, writer.py will write it when saving.
 339                 self.user_override = user_override
 340                 self.os, self.machine = _split_arch(arch)
 341                 self.langs = langs
 342
 343         def __str__(self):
 344                 return "<Feed from %s>" % self.uri
 345         __repr__ = __str__
 346
 347         arch = property(lambda self: _join_arch(self.os, self.machine))
 348
 349 class Dependency(object):
 350         """A Dependency indicates that an Implementation requires some additional
 351         code to function. This is an abstract base class.
 352         @ivar qdom: the XML element for this Dependency (since 0launch 0.51)
 353         @type qdom: L{qdom.Element}
 354         @ivar metadata: any extra attributes from the XML element
 355         @type metadata: {str: str}
 356         """
 357         __slots__ = ['qdom']
 358
 359         def __init__(self, element):
 360                 assert isinstance(element, qdom.Element), type(element) # Use InterfaceDependency instead!
 361                 self.qdom = element
 362
 363         @property
 364         def metadata(self):
 365                 return self.qdom.attrs
 366
 367 class InterfaceDependency(Dependency):
 368         """A Dependency on a Zero Install interface.
 369         @ivar interface: the interface required by this dependency
 370         @type interface: str
 371         @ivar restrictions: a list of constraints on acceptable implementations
 372         @type restrictions: [L{Restriction}]
 373         @ivar bindings: how to make the choice of implementation known
 374         @type bindings: [L{Binding}]
 375         @since: 0.28
 376         """
 377         __slots__ = ['interface', 'restrictions', 'bindings']
 378
 379         def __init__(self, interface, restrictions = None, element = None):
 380                 Dependency.__init__(self, element)
 381                 assert isinstance(interface, (str, unicode))
 382                 assert interface
 383                 self.interface = interface
 384                 if restrictions is None:
 385                         self.restrictions = []
 386                 else:
 387                         self.restrictions = restrictions
 388                 self.bindings = []
 389
 390         def __str__(self):
 391                 return _("<Dependency on %(interface)s; bindings: %(bindings)s%(restrictions)s>") % {'interface': self.interface, 'bindings': self.bindings, 'restrictions': self.restrictions}
 392
 393 class RetrievalMethod(object):
 394         """A RetrievalMethod provides a way to fetch an implementation."""
 395         __slots__ = []
 396
 397 class DownloadSource(RetrievalMethod):
 398         """A DownloadSource provides a way to fetch an implementation."""
 399         __slots__ = ['implementation', 'url', 'size', 'extract', 'start_offset', 'type']
 400
 401         def __init__(self, implementation, url, size, extract, start_offset = 0, type = None):
 402                 self.implementation = implementation
 403                 self.url = url
 404                 self.size = size
 405                 self.extract = extract
 406                 self.start_offset = start_offset
 407                 self.type = type                # MIME type - see unpack.py
 408
 409 class Recipe(RetrievalMethod):
 410         """Get an implementation by following a series of steps.
 411         @ivar size: the combined download sizes from all the steps
 412         @type size: int
 413         @ivar steps: the sequence of steps which must be performed
 414         @type steps: [L{RetrievalMethod}]"""
 415         __slots__ = ['steps']
 416
 417         def __init__(self):
 418                 self.steps = []
 419
 420         size = property(lambda self: sum([x.size for x in self.steps]))
 421
 422 class DistributionSource(RetrievalMethod):
 423         """A package that is installed using the distribution's tools (including PackageKit).
 424         @ivar install: a function to call to install this package
 425         @type install: (L{handler.Handler}) -> L{tasks.Blocker}
 426         @ivar package_id: the package name, in a form recognised by the distribution's tools
 427         @type package_id: str
 428         @ivar size: the download size in bytes
 429         @type size: int
 430         @ivar needs_confirmation: whether the user should be asked to confirm before calling install()
 431         @type needs_confirmation: bool"""
 432
 433         __slots__ = ['package_id', 'size', 'install', 'needs_confirmation']
 434
 435         def __init__(self, package_id, size, install, needs_confirmation = True):
 436                 RetrievalMethod.__init__(self)
 437                 self.package_id = package_id
 438                 self.size = size
 439                 self.install = install
 440                 self.needs_confirmation = needs_confirmation
 441
 442 class Command(object):
 443         """A Command is a way of running an Implementation as a program."""
 444
 445         __slots__ = ['qdom', '_depends', '_local_dir', '_runner']
 446
 447         def __init__(self, qdom, local_dir):
 448                 """@param qdom: the <command> element
 449                 @param local_dir: the directory containing the feed (for relative dependencies), or None if not local
 450                 """
 451                 assert qdom.name == 'command', 'not <command>: %s' % qdom
 452                 self.qdom = qdom
 453                 self._local_dir = local_dir
 454                 self._depends = None
 455
 456         path = property(lambda self: self.qdom.attrs.get("path", None))
 457
 458         def _toxml(self, doc, prefixes):
 459                 return self.qdom.toDOM(doc, prefixes)
 460
 461         @property
 462         def requires(self):
 463                 if self._depends is None:
 464                         self._runner = None
 465                         depends = []
 466                         for child in self.qdom.childNodes:
 467                                 if child.name == 'requires':
 468                                         dep = process_depends(child, self._local_dir)
 469                                         depends.append(dep)
 470                                 elif child.name == 'runner':
 471                                         if self._runner:
 472                                                 raise InvalidInterface(_("Multiple <runner>s in <command>!"))
 473                                         dep = process_depends(child, self._local_dir)
 474                                         depends.append(dep)
 475                                         self._runner = dep
 476                         self._depends = depends
 477                 return self._depends
 478
 479         def get_runner(self):
 480                 self.requires           # (sets _runner)
 481                 return self._runner
 482
 483 class Implementation(object):
 484         """An Implementation is a package which implements an Interface.
 485         @ivar download_sources: list of methods of getting this implementation
 486         @type download_sources: [L{RetrievalMethod}]
 487         @ivar feed: the feed owning this implementation (since 0.32)
 488         @type feed: [L{ZeroInstallFeed}]
 489         @ivar bindings: how to tell this component where it itself is located (since 0.31)
 490         @type bindings: [Binding]
 491         @ivar upstream_stability: the stability reported by the packager
 492         @type upstream_stability: [insecure | buggy | developer | testing | stable | packaged]
 493         @ivar user_stability: the stability as set by the user
 494         @type upstream_stability: [insecure | buggy | developer | testing | stable | packaged | preferred]
 495         @ivar langs: natural languages supported by this package
 496         @type langs: str
 497         @ivar requires: interfaces this package depends on
 498         @type requires: [L{Dependency}]
 499         @ivar commands: ways to execute as a program
 500         @type commands: {str: Command}
 501         @ivar metadata: extra metadata from the feed
 502         @type metadata: {"[URI ]localName": str}
 503         @ivar id: a unique identifier for this Implementation
 504         @ivar version: a parsed version number
 505         @ivar released: release date
 506         @ivar local_path: the directory containing this local implementation, or None if it isn't local (id isn't a path)
 507         @type local_path: str | None
 508         @ivar requires_root_install: whether the user will need admin rights to use this
 509         @type requires_root_install: bool
 510         """
 511
 512         # Note: user_stability shouldn't really be here
 513
 514         __slots__ = ['upstream_stability', 'user_stability', 'langs',
 515                      'requires', 'metadata', 'download_sources', 'commands',
 516                      'id', 'feed', 'version', 'released', 'bindings', 'machine']
 517
 518         def __init__(self, feed, id):
 519                 assert id
 520                 self.feed = feed
 521                 self.id = id
 522                 self.user_stability = None
 523                 self.upstream_stability = None
 524                 self.metadata = {}      # [URI + " "] + localName -> value
 525                 self.requires = []
 526                 self.version = None
 527                 self.released = None
 528                 self.download_sources = []
 529                 self.langs = ""
 530                 self.machine = None
 531                 self.bindings = []
 532                 self.commands = {}
 533
 534         def get_stability(self):
 535                 return self.user_stability or self.upstream_stability or testing
 536
 537         def __str__(self):
 538                 return self.id
 539
 540         def __repr__(self):
 541                 return "v%s (%s)" % (self.get_version(), self.id)
 542
 543         def __cmp__(self, other):
 544                 """Newer versions come first"""
 545                 d = cmp(other.version, self.version)
 546                 if d: return d
 547                 # If the version number is the same, just give a stable sort order, and
 548                 # ensure that two different implementations don't compare equal.
 549                 d = cmp(other.feed.url, self.feed.url)
 550                 if d: return d
 551                 return cmp(other.id, self.id)
 552
 553         def get_version(self):
 554                 """Return the version as a string.
 555                 @see: L{format_version}
 556                 """
 557                 return format_version(self.version)
 558
 559         arch = property(lambda self: _join_arch(self.os, self.machine))
 560
 561         os = None
 562         local_path = None
 563         digests = None
 564         requires_root_install = False
 565
 566         def _get_main(self):
 567                 """"@deprecated: use commands["run"] instead"""
 568                 main = self.commands.get("run", None)
 569                 if main is not None:
 570                         return main.path
 571                 return None
 572         def _set_main(self, path):
 573                 """"@deprecated: use commands["run"] instead"""
 574                 if path is None:
 575                         if "run" in self.commands:
 576                                 del self.commands["run"]
 577                 else:
 578                         self.commands["run"] = Command(qdom.Element(XMLNS_IFACE, 'command', {'path': path}), None)
 579         main = property(_get_main, _set_main)
 580
 581         def is_available(self, stores):
 582                 """Is this Implementation available locally?
 583                 (a local implementation, an installed distribution package, or a cached ZeroInstallImplementation)
 584                 @rtype: bool
 585                 @since: 0.53
 586                 """
 587                 raise NotImplementedError("abstract")
 588
 589 class DistributionImplementation(Implementation):
 590         """An implementation provided by the distribution. Information such as the version
 591         comes from the package manager.
 592         @since: 0.28"""
 593         __slots__ = ['distro', 'installed']
 594
 595         def __init__(self, feed, id, distro):
 596                 assert id.startswith('package:')
 597                 Implementation.__init__(self, feed, id)
 598                 self.distro = distro
 599                 self.installed = False
 600
 601         @property
 602         def requires_root_install(self):
 603                 return not self.installed
 604
 605         def is_available(self, stores):
 606                 return self.installed
 607
 608 class ZeroInstallImplementation(Implementation):
 609         """An implementation where all the information comes from Zero Install.
 610         @ivar digests: a list of "algorith=value" strings (since 0.45)
 611         @type digests: [str]
 612         @since: 0.28"""
 613         __slots__ = ['os', 'size', 'digests', 'local_path']
 614
 615         def __init__(self, feed, id, local_path):
 616                 """id can be a local path (string starting with /) or a manifest hash (eg "sha1=XXX")"""
 617                 assert not id.startswith('package:'), id
 618                 Implementation.__init__(self, feed, id)
 619                 self.size = None
 620                 self.os = None
 621                 self.digests = []
 622                 self.local_path = local_path
 623
 624         # Deprecated
 625         dependencies = property(lambda self: dict([(x.interface, x) for x in self.requires
 626                                                    if isinstance(x, InterfaceDependency)]))
 627
 628         def add_download_source(self, url, size, extract, start_offset = 0, type = None):
 629                 """Add a download source."""
 630                 self.download_sources.append(DownloadSource(self, url, size, extract, start_offset, type))
 631
 632         def set_arch(self, arch):
 633                 self.os, self.machine = _split_arch(arch)
 634         arch = property(lambda self: _join_arch(self.os, self.machine), set_arch)
 635
 636         def is_available(self, stores):
 637                 if self.local_path is not None:
 638                         return os.path.exists(self.local_path)
 639                 if self.digests:
 640                         path = stores.lookup_maybe(self.digests)
 641                         return path is not None
 642                 return False    # (0compile creates fake entries with no digests)
 643
 644 class Interface(object):
 645         """An Interface represents some contract of behaviour.
 646         @ivar uri: the URI for this interface.
 647         @ivar stability_policy: user's configured policy.
 648         Implementations at this level or higher are preferred.
 649         Lower levels are used only if there is no other choice.
 650         """
 651         __slots__ = ['uri', 'stability_policy', 'extra_feeds']
 652
 653         implementations = property(lambda self: self._main_feed.implementations)
 654         name = property(lambda self: self._main_feed.name)
 655         description = property(lambda self: self._main_feed.description)
 656         summary = property(lambda self: self._main_feed.summary)
 657         last_modified = property(lambda self: self._main_feed.last_modified)
 658         feeds = property(lambda self: self.extra_feeds + self._main_feed.feeds)
 659         metadata = property(lambda self: self._main_feed.metadata)
 660
 661         last_checked = property(lambda self: self._main_feed.last_checked)
 662
 663         def __init__(self, uri):
 664                 assert uri
 665                 if uri.startswith('http:') or uri.startswith('https:') or os.path.isabs(uri):
 666                         self.uri = uri
 667                 else:
 668                         raise SafeException(_("Interface name '%s' doesn't start "
 669                                             "with 'http:' or 'https:'") % uri)
 670                 self.reset()
 671
 672         def _get_feed_for(self):
 673                 retval = {}
 674                 for key in self._main_feed.feed_for:
 675                         retval[key] = True
 676                 return retval
 677         feed_for = property(_get_feed_for)      # Deprecated (used by 0publish)
 678
 679         def reset(self):
 680                 self.extra_feeds = []
 681                 self.stability_policy = None
 682
 683         def get_name(self):
 684                 from zeroinstall.injector.iface_cache import iface_cache
 685                 feed = iface_cache.get_feed(self.uri)
 686                 if feed:
 687                         return feed.get_name()
 688                 return '(' + os.path.basename(self.uri) + ')'
 689
 690         def __repr__(self):
 691                 return _("<Interface %s>") % self.uri
 692
 693         def set_stability_policy(self, new):
 694                 assert new is None or isinstance(new, Stability)
 695                 self.stability_policy = new
 696
 697         def get_feed(self, url):
 698                 #import warnings
 699                 #warnings.warn("use iface_cache.get_feed instead", DeprecationWarning, 2)
 700                 for x in self.extra_feeds:
 701                         if x.uri == url:
 702                                 return x
 703                 #return self._main_feed.get_feed(url)
 704                 return None
 705
 706         def get_metadata(self, uri, name):
 707                 return self._main_feed.get_metadata(uri, name)
 708
 709         @property
 710         def _main_feed(self):
 711                 #import warnings
 712                 #warnings.warn("use the feed instead", DeprecationWarning, 3)
 713                 from zeroinstall.injector import policy
 714                 iface_cache = policy.get_deprecated_singleton_config().iface_cache
 715                 feed = iface_cache.get_feed(self.uri)
 716                 if feed is None:
 717                         return _dummy_feed
 718                 return feed
 719
 720 def _merge_attrs(attrs, item):
 721         """Add each attribute of item to a copy of attrs and return the copy.
 722         @type attrs: {str: str}
 723         @type item: L{qdom.Element}
 724         @rtype: {str: str}
 725         """
 726         new = attrs.copy()
 727         for a in item.attrs:
 728                 new[str(a)] = item.attrs[a]
 729         return new
 730
 731 def _get_long(elem, attr_name):
 732         val = elem.getAttribute(attr_name)
 733         if val is not None:
 734                 try:
 735                         val = int(val)
 736                 except ValueError:
 737                         raise SafeException(_("Invalid value for integer attribute '%(attribute_name)s': %(value)s") % {'attribute_name': attr_name, 'value': val})
 738         return val
 739
 740 class ZeroInstallFeed(object):
 741         """A feed lists available implementations of an interface.
 742         @ivar url: the URL for this feed
 743         @ivar implementations: Implementations in this feed, indexed by ID
 744         @type implementations: {str: L{Implementation}}
 745         @ivar name: human-friendly name
 746         @ivar summaries: short textual description (in various languages, since 0.49)
 747         @type summaries: {str: str}
 748         @ivar descriptions: long textual description (in various languages, since 0.49)
 749         @type descriptions: {str: str}
 750         @ivar last_modified: timestamp on signature
 751         @ivar last_checked: time feed was last successfully downloaded and updated
 752         @ivar feeds: list of <feed> elements in this feed
 753         @type feeds: [L{Feed}]
 754         @ivar feed_for: interfaces for which this could be a feed
 755         @type feed_for: set(str)
 756         @ivar metadata: extra elements we didn't understand
 757         """
 758         # _main is deprecated
 759         __slots__ = ['url', 'implementations', 'name', 'descriptions', 'first_description', 'summaries', 'first_summary', '_package_implementations',
 760                      'last_checked', 'last_modified', 'feeds', 'feed_for', 'metadata']
 761
 762         def __init__(self, feed_element, local_path = None, distro = None):
 763                 """Create a feed object from a DOM.
 764                 @param feed_element: the root element of a feed file
 765                 @type feed_element: L{qdom.Element}
 766                 @param local_path: the pathname of this local feed, or None for remote feeds"""
 767                 self.implementations = {}
 768                 self.name = None
 769                 self.summaries = {}     # { lang: str }
 770                 self.first_summary = None
 771                 self.descriptions = {}  # { lang: str }
 772                 self.first_description = None
 773                 self.last_modified = None
 774                 self.feeds = []
 775                 self.feed_for = set()
 776                 self.metadata = []
 777                 self.last_checked = None
 778                 self._package_implementations = []
 779
 780                 if distro is not None:
 781                         import warnings
 782                         warnings.warn("distro argument is now ignored", DeprecationWarning, 2)
 783
 784                 if feed_element is None:
 785                         return                  # XXX subclass?
 786
 787                 assert feed_element.name in ('interface', 'feed'), "Root element should be <interface>, not %s" % feed_element
 788                 assert feed_element.uri == XMLNS_IFACE, "Wrong namespace on root element: %s" % feed_element.uri
 789
 790                 main = feed_element.getAttribute('main')
 791                 #if main: warn("Setting 'main' on the root element is deprecated. Put it on a <group> instead")
 792
 793                 if local_path:
 794                         self.url = local_path
 795                         local_dir = os.path.dirname(local_path)
 796                 else:
 797                         self.url = feed_element.getAttribute('uri')
 798                         if not self.url:
 799                                 raise InvalidInterface(_("<interface> uri attribute missing"))
 800                         local_dir = None        # Can't have relative paths
 801
 802                 min_injector_version = feed_element.getAttribute('min-injector-version')
 803                 if min_injector_version:
 804                         if parse_version(min_injector_version) > parse_version(version):
 805                                 raise InvalidInterface(_("This feed requires version %(min_version)s or later of "
 806                                                         "Zero Install, but I am only version %(version)s. "
 807                                                         "You can get a newer version from http://0install.net") %
 808                                                         {'min_version': min_injector_version, 'version': version})
 809
 810                 for x in feed_element.childNodes:
 811                         if x.uri != XMLNS_IFACE:
 812                                 self.metadata.append(x)
 813                                 continue
 814                         if x.name == 'name':
 815                                 self.name = x.content
 816                         elif x.name == 'description':
 817                                 if self.first_description == None:
 818                                         self.first_description = x.content
 819                                 self.descriptions[x.attrs.get("http://www.w3.org/XML/1998/namespace lang", 'en')] = x.content
 820                         elif x.name == 'summary':
 821                                 if self.first_summary == None:
 822                                         self.first_summary = x.content
 823                                 self.summaries[x.attrs.get("http://www.w3.org/XML/1998/namespace lang", 'en')] = x.content
 824                         elif x.name == 'feed-for':
 825                                 feed_iface = x.getAttribute('interface')
 826                                 if not feed_iface:
 827                                         raise InvalidInterface(_('Missing "interface" attribute in <feed-for>'))
 828                                 self.feed_for.add(feed_iface)
 829                                 # Bug report from a Debian/stable user that --feed gets the wrong value.
 830                                 # Can't reproduce (even in a Debian/stable chroot), but add some logging here
 831                                 # in case it happens again.
 832                                 debug(_("Is feed-for %s"), feed_iface)
 833                         elif x.name == 'feed':
 834                                 feed_src = x.getAttribute('src')
 835                                 if not feed_src:
 836                                         raise InvalidInterface(_('Missing "src" attribute in <feed>'))
 837                                 if feed_src.startswith('http:') or feed_src.startswith('https:') or local_path:
 838                                         langs = x.getAttribute('langs')
 839                                         if langs: langs = langs.replace('_', '-')
 840                                         self.feeds.append(Feed(feed_src, x.getAttribute('arch'), False, langs = langs))
 841                                 else:
 842                                         raise InvalidInterface(_("Invalid feed URL '%s'") % feed_src)
 843                         else:
 844                                 self.metadata.append(x)
 845
 846                 if not self.name:
 847                         raise InvalidInterface(_("Missing <name> in feed"))
 848                 if not self.summary:
 849                         raise InvalidInterface(_("Missing <summary> in feed"))
 850
 851                 def process_group(group, group_attrs, base_depends, base_bindings, base_commands):
 852                         for item in group.childNodes:
 853                                 if item.uri != XMLNS_IFACE: continue
 854
 855                                 if item.name not in ('group', 'implementation', 'package-implementation'):
 856                                         continue
 857
 858                                 # We've found a group or implementation. Scan for dependencies,
 859                                 # bindings and commands. Doing this here means that:
 860                                 # - We can share the code for groups and implementations here.
 861                                 # - The order doesn't matter, because these get processed first.
 862                                 # A side-effect is that the document root cannot contain
 863                                 # these.
 864
 865                                 depends = base_depends[:]
 866                                 bindings = base_bindings[:]
 867                                 commands = base_commands.copy()
 868
 869                                 for attr, command in [('main', 'run'),
 870                                                       ('self-test', 'test')]:
 871                                         value = item.attrs.get(attr, None)
 872                                         if value is not None:
 873                                                 commands[command] = Command(qdom.Element(XMLNS_IFACE, 'command', {'path': value}), None)
 874
 875                                 for child in item.childNodes:
 876                                         if child.uri != XMLNS_IFACE: continue
 877                                         if child.name == 'requires':
 878                                                 dep = process_depends(child, local_dir)
 879                                                 depends.append(dep)
 880                                         elif child.name == 'command':
 881                                                 command_name = child.attrs.get('name', None)
 882                                                 if not command_name:
 883                                                         raise InvalidInterface('Missing name for <command>')
 884                                                 commands[command_name] = Command(child, local_dir)
 885                                         elif child.name in binding_names:
 886                                                 bindings.append(process_binding(child))
 887
 888                                 compile_command = item.attrs.get('http://zero-install.sourceforge.net/2006/namespaces/0compile command')
 889                                 if compile_command is not None:
 890                                         commands['compile'] = Command(qdom.Element(XMLNS_IFACE, 'command', {'shell-command': compile_command}), None)
 891
 892                                 item_attrs = _merge_attrs(group_attrs, item)
 893
 894                                 if item.name == 'group':
 895                                         process_group(item, item_attrs, depends, bindings, commands)
 896                                 elif item.name == 'implementation':
 897                                         process_impl(item, item_attrs, depends, bindings, commands)
 898                                 elif item.name == 'package-implementation':
 899                                         if depends:
 900                                                 warn("A <package-implementation> with dependencies in %s!", self.url)
 901                                         self._package_implementations.append((item, item_attrs))
 902                                 else:
 903                                         assert 0
 904
 905                 def process_impl(item, item_attrs, depends, bindings, commands):
 906                         id = item.getAttribute('id')
 907                         if id is None:
 908                                 raise InvalidInterface(_("Missing 'id' attribute on %s") % item)
 909                         local_path = item_attrs.get('local-path')
 910                         if local_dir and local_path:
 911                                 abs_local_path = os.path.abspath(os.path.join(local_dir, local_path))
 912                                 impl = ZeroInstallImplementation(self, id, abs_local_path)
 913                         elif local_dir and (id.startswith('/') or id.startswith('.')):
 914                                 # For old feeds
 915                                 id = os.path.abspath(os.path.join(local_dir, id))
 916                                 impl = ZeroInstallImplementation(self, id, id)
 917                         else:
 918                                 impl = ZeroInstallImplementation(self, id, None)
 919                                 if '=' in id:
 920                                         # In older feeds, the ID was the (single) digest
 921                                         impl.digests.append(id)
 922                         if id in self.implementations:
 923                                 warn(_("Duplicate ID '%(id)s' in feed '%(feed)s'"), {'id': id, 'feed': self})
 924                         self.implementations[id] = impl
 925
 926                         impl.metadata = item_attrs
 927                         try:
 928                                 version_mod = item_attrs.get('version-modifier', None)
 929                                 if version_mod:
 930                                         item_attrs['version'] += version_mod
 931                                         del item_attrs['version-modifier']
 932                                 version = item_attrs['version']
 933                         except KeyError:
 934                                 raise InvalidInterface(_("Missing version attribute"))
 935                         impl.version = parse_version(version)
 936
 937                         impl.commands = commands
 938
 939                         impl.released = item_attrs.get('released', None)
 940                         impl.langs = item_attrs.get('langs', '').replace('_', '-')
 941
 942                         size = item.getAttribute('size')
 943                         if size:
 944                                 impl.size = int(size)
 945                         impl.arch = item_attrs.get('arch', None)
 946                         try:
 947                                 stability = stability_levels[str(item_attrs['stability'])]
 948                         except KeyError:
 949                                 stab = str(item_attrs['stability'])
 950                                 if stab != stab.lower():
 951                                         raise InvalidInterface(_('Stability "%s" invalid - use lower case!') % item_attrs.stability)
 952                                 raise InvalidInterface(_('Stability "%s" invalid') % item_attrs['stability'])
 953                         if stability >= preferred:
 954                                 raise InvalidInterface(_("Upstream can't set stability to preferred!"))
 955                         impl.upstream_stability = stability
 956
 957                         impl.bindings = bindings
 958                         impl.requires = depends
 959
 960                         for elem in item.childNodes:
 961                                 if elem.uri != XMLNS_IFACE: continue
 962                                 if elem.name == 'archive':
 963                                         url = elem.getAttribute('href')
 964                                         if not url:
 965                                                 raise InvalidInterface(_("Missing href attribute on <archive>"))
 966                                         size = elem.getAttribute('size')
 967                                         if not size:
 968                                                 raise InvalidInterface(_("Missing size attribute on <archive>"))
 969                                         impl.add_download_source(url = url, size = int(size),
 970                                                         extract = elem.getAttribute('extract'),
 971                                                         start_offset = _get_long(elem, 'start-offset'),
 972                                                         type = elem.getAttribute('type'))
 973                                 elif elem.name == 'manifest-digest':
 974                                         for aname, avalue in elem.attrs.iteritems():
 975                                                 if ' ' not in aname:
 976                                                         impl.digests.append('%s=%s' % (aname, avalue))
 977                                 elif elem.name == 'recipe':
 978                                         recipe = Recipe()
 979                                         for recipe_step in elem.childNodes:
 980                                                 if recipe_step.uri == XMLNS_IFACE and recipe_step.name == 'archive':
 981                                                         url = recipe_step.getAttribute('href')
 982                                                         if not url:
 983                                                                 raise InvalidInterface(_("Missing href attribute on <archive>"))
 984                                                         size = recipe_step.getAttribute('size')
 985                                                         if not size:
 986                                                                 raise InvalidInterface(_("Missing size attribute on <archive>"))
 987                                                         recipe.steps.append(DownloadSource(None, url = url, size = int(size),
 988                                                                         extract = recipe_step.getAttribute('extract'),
 989                                                                         start_offset = _get_long(recipe_step, 'start-offset'),
 990                                                                         type = recipe_step.getAttribute('type')))
 991                                                 else:
 992                                                         info(_("Unknown step '%s' in recipe; skipping recipe"), recipe_step.name)
 993                                                         break
 994                                         else:
 995                                                 impl.download_sources.append(recipe)
 996
 997                 root_attrs = {'stability': 'testing'}
 998                 root_commands = {}
 999                 if main:
1000                         info("Note: @main on document element is deprecated in %s", self)
1001                         root_commands['run'] = Command(qdom.Element(XMLNS_IFACE, 'command', {'path': main}), None)
1002                 process_group(feed_element, root_attrs, [], [], root_commands)
1003
1004         def get_distro_feed(self):
1005                 """Does this feed contain any <pacakge-implementation> elements?
1006                 i.e. is it worth asking the package manager for more information?
1007                 @return: the URL of the virtual feed, or None
1008                 @since: 0.49"""
1009                 if self._package_implementations:
1010                         return "distribution:" + self.url
1011                 return None
1012
1013         def get_package_impls(self, distro):
1014                 """Find the best <pacakge-implementation> element(s) for the given distribution.
1015                 @param distro: the distribution to use to rate them
1016                 @type distro: L{distro.Distribution}
1017                 @return: a list of tuples for the best ranked elements
1018                 @rtype: [str]
1019                 @since: 0.49"""
1020                 best_score = 0
1021                 best_impls = []
1022
1023                 for item, item_attrs in self._package_implementations:
1024                         distro_names = item_attrs.get('distributions', '')
1025                         for distro_name in distro_names.split(' '):
1026                                 score = distro.get_score(distro_name)
1027                                 if score > best_score:
1028                                         best_score = score
1029                                         best_impls = []
1030                                 if score == best_score:
1031                                         best_impls.append((item, item_attrs))
1032                 return best_impls
1033
1034         def get_name(self):
1035                 return self.name or '(' + os.path.basename(self.url) + ')'
1036
1037         def __repr__(self):
1038                 return _("<Feed %s>") % self.url
1039
1040         def set_stability_policy(self, new):
1041                 assert new is None or isinstance(new, Stability)
1042                 self.stability_policy = new
1043
1044         def get_feed(self, url):
1045                 for x in self.feeds:
1046                         if x.uri == url:
1047                                 return x
1048                 return None
1049
1050         def add_metadata(self, elem):
1051                 self.metadata.append(elem)
1052
1053         def get_metadata(self, uri, name):
1054                 """Return a list of interface metadata elements with this name and namespace URI."""
1055                 return [m for m in self.metadata if m.name == name and m.uri == uri]
1056
1057         @property
1058         def summary(self):
1059                 return _best_language_match(self.summaries) or self.first_summary
1060
1061         @property
1062         def description(self):
1063                 return _best_language_match(self.descriptions) or self.first_description
1064
1065 class DummyFeed(object):
1066         """Temporary class used during API transition."""
1067         last_modified = None
1068         name = '-'
1069         last_checked = property(lambda self: None)
1070         implementations = property(lambda self: {})
1071         feeds = property(lambda self: [])
1072         summary = property(lambda self: '-')
1073         description = property(lambda self: '')
1074         def get_name(self): return self.name
1075         def get_feed(self, url): return None
1076         def get_metadata(self, uri, name): return []
1077 _dummy_feed = DummyFeed()
1078
1079 def unescape(uri):
1080         """Convert each %20 to a space, etc.
1081         @rtype: str"""
1082         uri = uri.replace('#', '/')
1083         if '%' not in uri: return uri
1084         return re.sub('%[0-9a-fA-F][0-9a-fA-F]',
1085                 lambda match: chr(int(match.group(0)[1:], 16)),
1086                 uri).decode('utf-8')
1087
1088 def escape(uri):
1089         """Convert each space to %20, etc
1090         @rtype: str"""
1091         return re.sub('[^-_.a-zA-Z0-9]',
1092                 lambda match: '%%%02x' % ord(match.group(0)),
1093                 uri.encode('utf-8'))
1094
1095 def _pretty_escape(uri):
1096         """Convert each space to %20, etc
1097         : is preserved and / becomes #. This makes for nicer strings,
1098         and may replace L{escape} everywhere in future.
1099         @rtype: str"""
1100         return re.sub('[^-_.a-zA-Z0-9:/]',
1101                 lambda match: '%%%02x' % ord(match.group(0)),
1102                 uri.encode('utf-8')).replace('/', '#')
1103
1104 def canonical_iface_uri(uri):
1105         """If uri is a relative path, convert to an absolute one.
1106         A "file:///foo" URI is converted to "/foo".
1107         An "alias:prog" URI expands to the URI in the 0alias script
1108         Otherwise, return it unmodified.
1109         @rtype: str
1110         @raise SafeException: if uri isn't valid
1111         """
1112         if uri.startswith('http://') or uri.startswith('https://'):
1113                 if uri.count("/") < 3:
1114                         raise SafeException(_("Missing / after hostname in URI '%s'") % uri)
1115                 return uri
1116         elif uri.startswith('file:///'):
1117                 return uri[7:]
1118         elif uri.startswith('alias:'):
1119                 from zeroinstall import alias, support
1120                 alias_prog = uri[6:]
1121                 if not os.path.isabs(alias_prog):
1122                         full_path = support.find_in_path(alias_prog)
1123                         if not full_path:
1124                                 raise alias.NotAnAliasScript("Not found in $PATH: " + alias_prog)
1125                 else:
1126                         full_path = alias_prog
1127                 interface_uri, main = alias.parse_script(full_path)
1128                 return interface_uri
1129         else:
1130                 iface_uri = os.path.realpath(uri)
1131                 if os.path.isfile(iface_uri):
1132                         return iface_uri
1133         raise SafeException(_("Bad interface name '%(uri)s'.\n"
1134                         "(doesn't start with 'http:', and "
1135                         "doesn't exist as a local file '%(interface_uri)s' either)") %
1136                         {'uri': uri, 'interface_uri': iface_uri})
1137
1138 _version_mod_to_value = {
1139         'pre': -2,
1140         'rc': -1,
1141         '': 0,
1142         'post': 1,
1143 }
1144
1145 # Reverse mapping
1146 _version_value_to_mod = {}
1147 for x in _version_mod_to_value: _version_value_to_mod[_version_mod_to_value[x]] = x
1148 del x
1149
1150 _version_re = re.compile('-([a-z]*)')
1151
1152 def parse_version(version_string):
1153         """Convert a version string to an internal representation.
1154         The parsed format can be compared quickly using the standard Python functions.
1155          - Version := DottedList ("-" Mod DottedList?)*
1156          - DottedList := (Integer ("." Integer)*)
1157         @rtype: tuple (opaque)
1158         @raise SafeException: if the string isn't a valid version
1159         @since: 0.24 (moved from L{reader}, from where it is still available):"""
1160         if version_string is None: return None
1161         parts = _version_re.split(version_string)
1162         if parts[-1] == '':
1163                 del parts[-1]   # Ends with a modifier
1164         else:
1165                 parts.append('')
1166         if not parts:
1167                 raise SafeException(_("Empty version string!"))
1168         l = len(parts)
1169         try:
1170                 for x in range(0, l, 2):
1171                         part = parts[x]
1172                         if part:
1173                                 parts[x] = map(int, parts[x].split('.'))
1174                         else:
1175                                 parts[x] = []   # (because ''.split('.') == [''], not [])
1176                 for x in range(1, l, 2):
1177                         parts[x] = _version_mod_to_value[parts[x]]
1178                 return parts
1179         except ValueError, ex:
1180                 raise SafeException(_("Invalid version format in '%(version_string)s': %(exception)s") % {'version_string': version_string, 'exception': ex})
1181         except KeyError, ex:
1182                 raise SafeException(_("Invalid version modifier in '%(version_string)s': %(exception)s") % {'version_string': version_string, 'exception': ex})
1183
1184 def format_version(version):
1185         """Format a parsed version for display. Undoes the effect of L{parse_version}.
1186         @see: L{Implementation.get_version}
1187         @rtype: str
1188         @since: 0.24"""
1189         version = version[:]
1190         l = len(version)
1191         for x in range(0, l, 2):
1192                 version[x] = '.'.join(map(str, version[x]))
1193         for x in range(1, l, 2):
1194                 version[x] = '-' + _version_value_to_mod[version[x]]
1195         if version[-1] == '-': del version[-1]
1196         return ''.join(version)
1197