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 import os, re
  17 from logging import info, debug
  18 from zeroinstall import SafeException, version
  19 from zeroinstall.injector.namespaces import XMLNS_IFACE
  20
  21 # Element names for bindings in feed files
  22 binding_names = frozenset(['environment', 'overlay'])
  23
  24 network_offline = 'off-line'
  25 network_minimal = 'minimal'
  26 network_full = 'full'
  27 network_levels = (network_offline, network_minimal, network_full)
  28
  29 stability_levels = {}   # Name -> Stability
  30
  31 defaults = {
  32         'PATH': '/bin:/usr/bin',
  33         'XDG_CONFIG_DIRS': '/etc/xdg',
  34         'XDG_DATA_DIRS': '/usr/local/share:/usr/share',
  35 }
  36
  37 class InvalidInterface(SafeException):
  38         """Raised when parsing an invalid feed."""
  39         def __init__(self, message, ex = None):
  40                 if ex:
  41                         message += "\n\n(exact error: %s)" % ex
  42                 SafeException.__init__(self, message)
  43
  44 def _split_arch(arch):
  45         """Split an arch into an (os, machine) tuple. Either or both parts may be None."""
  46         if not arch:
  47                 return None, None
  48         elif '-' not in arch:
  49                 raise SafeException(_("Malformed arch '%s'") % arch)
  50         else:
  51                 osys, machine = arch.split('-', 1)
  52                 if osys == '*': osys = None
  53                 if machine == '*': machine = None
  54                 return osys, machine
  55
  56 def _join_arch(osys, machine):
  57         if osys == machine == None: return None
  58         return "%s-%s" % (osys or '*', machine or '*')
  59
  60 class Stability(object):
  61         """A stability rating. Each implementation has an upstream stability rating and,
  62         optionally, a user-set rating."""
  63         __slots__ = ['level', 'name', 'description']
  64         def __init__(self, level, name, description):
  65                 self.level = level
  66                 self.name = name
  67                 self.description = description
  68                 assert name not in stability_levels
  69                 stability_levels[name] = self
  70
  71         def __cmp__(self, other):
  72                 return cmp(self.level, other.level)
  73
  74         def __str__(self):
  75                 return self.name
  76
  77         def __repr__(self):
  78                 return _("<Stability: %s>") % self.description
  79
  80 def process_binding(e):
  81         """Internal"""
  82         if e.name == 'environment':
  83                 mode = {
  84                         None: EnvironmentBinding.PREPEND,
  85                         'prepend': EnvironmentBinding.PREPEND,
  86                         'append': EnvironmentBinding.APPEND,
  87                         'replace': EnvironmentBinding.REPLACE,
  88                 }[e.getAttribute('mode')]
  89
  90                 binding = EnvironmentBinding(e.getAttribute('name'),
  91                                              insert = e.getAttribute('insert'),
  92                                              default = e.getAttribute('default'),
  93                                              mode = mode)
  94                 if not binding.name: raise InvalidInterface(_("Missing 'name' in binding"))
  95                 if binding.insert is None: raise InvalidInterface(_("Missing 'insert' in binding"))
  96                 return binding
  97         elif e.name == 'overlay':
  98                 return OverlayBinding(e.getAttribute('src'), e.getAttribute('mount-point'))
  99         else:
 100                 raise Exception(_("Unknown binding type '%s'") % e.name)
 101
 102 def process_depends(item):
 103         """Internal"""
 104         # Note: also called from selections
 105         dep_iface = item.getAttribute('interface')
 106         if not dep_iface:
 107                 raise InvalidInterface(_("Missing 'interface' on <requires>"))
 108         dependency = InterfaceDependency(dep_iface, metadata = item.attrs)
 109
 110         for e in item.childNodes:
 111                 if e.uri != XMLNS_IFACE: continue
 112                 if e.name in binding_names:
 113                         dependency.bindings.append(process_binding(e))
 114                 elif e.name == 'version':
 115                         dependency.restrictions.append(
 116                                 VersionRangeRestriction(not_before = parse_version(e.getAttribute('not-before')),
 117                                                         before = parse_version(e.getAttribute('before'))))
 118         return dependency
 119
 120 def N_(message): return message
 121
 122 insecure = Stability(0, N_('insecure'), _('This is a security risk'))
 123 buggy = Stability(5, N_('buggy'), _('Known to have serious bugs'))
 124 developer = Stability(10, N_('developer'), _('Work-in-progress - bugs likely'))
 125 testing = Stability(20, N_('testing'), _('Stability unknown - please test!'))
 126 stable = Stability(30, N_('stable'), _('Tested - no serious problems found'))
 127 packaged = Stability(35, N_('packaged'), _('Supplied by the local package manager'))
 128 preferred = Stability(40, N_('preferred'), _('Best of all - must be set manually'))
 129
 130 del N_
 131
 132 class Restriction(object):
 133         """A Restriction limits the allowed implementations of an Interface."""
 134         __slots__ = []
 135
 136         def meets_restriction(self, impl):
 137                 """Called by the L{Solver} to check whether a particular implementation is acceptable.
 138                 @return: False if this implementation is not a possibility
 139                 @rtype: bool
 140                 """
 141                 raise NotImplementedError(_("Abstract"))
 142
 143 class VersionRestriction(Restriction):
 144         """Only select implementations with a particular version number.
 145         @since: 0.40"""
 146
 147         def __init__(self, version):
 148                 """@param version: the required version number
 149                 @see: L{parse_version}; use this to pre-process the version number
 150                 """
 151                 self.version = version
 152
 153         def meets_restriction(self, impl):
 154                 return impl.version == self.version
 155
 156         def __str__(self):
 157                 return _("(restriction: version = %s)") % format_version(self.version)
 158
 159 class VersionRangeRestriction(Restriction):
 160         """Only versions within the given range are acceptable"""
 161         __slots__ = ['before', 'not_before']
 162
 163         def __init__(self, before, not_before):
 164                 """@param before: chosen versions must be earlier than this
 165                 @param not_before: versions must be at least this high
 166                 @see: L{parse_version}; use this to pre-process the versions
 167                 """
 168                 self.before = before
 169                 self.not_before = not_before
 170
 171         def meets_restriction(self, impl):
 172                 if self.not_before and impl.version < self.not_before:
 173                         return False
 174                 if self.before and impl.version >= self.before:
 175                         return False
 176                 return True
 177
 178         def __str__(self):
 179                 if self.not_before is not None or self.before is not None:
 180                         range = ''
 181                         if self.not_before is not None:
 182                                 range += format_version(self.not_before) + ' <= '
 183                         range += 'version'
 184                         if self.before is not None:
 185                                 range += ' < ' + format_version(self.before)
 186                 else:
 187                         range = 'none'
 188                 return _("(restriction: %s)") % range
 189
 190 class Binding(object):
 191         """Information about how the choice of a Dependency is made known
 192         to the application being run."""
 193
 194 class EnvironmentBinding(Binding):
 195         """Indicate the chosen implementation using an environment variable."""
 196         __slots__ = ['name', 'insert', 'default', 'mode']
 197
 198         PREPEND = 'prepend'
 199         APPEND = 'append'
 200         REPLACE = 'replace'
 201
 202         def __init__(self, name, insert, default = None, mode = PREPEND):
 203                 """mode argument added in version 0.28"""
 204                 self.name = name
 205                 self.insert = insert
 206                 self.default = default
 207                 self.mode = mode
 208
 209         def __str__(self):
 210                 return _("<environ %(name)s %(mode)s %(insert)s>") % {'name': self.name,'mode':  self.mode, 'insert': self.insert}
 211
 212         __repr__ = __str__
 213
 214         def get_value(self, path, old_value):
 215                 """Calculate the new value of the environment variable after applying this binding.
 216                 @param path: the path to the selected implementation
 217                 @param old_value: the current value of the environment variable
 218                 @return: the new value for the environment variable"""
 219                 extra = os.path.join(path, self.insert)
 220
 221                 if self.mode == EnvironmentBinding.REPLACE:
 222                         return extra
 223
 224                 if old_value is None:
 225                         old_value = self.default or defaults.get(self.name, None)
 226                 if old_value is None:
 227                         return extra
 228                 if self.mode == EnvironmentBinding.PREPEND:
 229                         return extra + ':' + old_value
 230                 else:
 231                         return old_value + ':' + extra
 232
 233         def _toxml(self, doc):
 234                 """Create a DOM element for this binding.
 235                 @param doc: document to use to create the element
 236                 @return: the new element
 237                 """
 238                 env_elem = doc.createElementNS(XMLNS_IFACE, 'environment')
 239                 env_elem.setAttributeNS(None, 'name', self.name)
 240                 env_elem.setAttributeNS(None, 'insert', self.insert)
 241                 if self.default:
 242                         env_elem.setAttributeNS(None, 'default', self.default)
 243                 return env_elem
 244
 245 class OverlayBinding(Binding):
 246         """Make the chosen implementation available by overlaying it onto another part of the file-system.
 247         This is to support legacy programs which use hard-coded paths."""
 248         __slots__ = ['src', 'mount_point']
 249
 250         def __init__(self, src, mount_point):
 251                 self.src = src
 252                 self.mount_point = mount_point
 253
 254         def __str__(self):
 255                 return _("<overlay %(src)s on %(mount_point)s>") % {'src': self.src or '.', 'mount_point': self.mount_point or '/'}
 256
 257         __repr__ = __str__
 258
 259         def _toxml(self, doc):
 260                 """Create a DOM element for this binding.
 261                 @param doc: document to use to create the element
 262                 @return: the new element
 263                 """
 264                 env_elem = doc.createElementNS(XMLNS_IFACE, 'overlay')
 265                 if self.src is not None:
 266                         env_elem.setAttributeNS(None, 'src', self.src)
 267                 if self.mount_point is not None:
 268                         env_elem.setAttributeNS(None, 'mount-point', self.mount_point)
 269                 return env_elem
 270
 271 class Feed(object):
 272         """An interface's feeds are other interfaces whose implementations can also be
 273         used as implementations of this interface."""
 274         __slots__ = ['uri', 'os', 'machine', 'user_override', 'langs']
 275         def __init__(self, uri, arch, user_override, langs = None):
 276                 self.uri = uri
 277                 # This indicates whether the feed comes from the user's overrides
 278                 # file. If true, writer.py will write it when saving.
 279                 self.user_override = user_override
 280                 self.os, self.machine = _split_arch(arch)
 281                 self.langs = langs
 282
 283         def __str__(self):
 284                 return "<Feed from %s>" % self.uri
 285         __repr__ = __str__
 286
 287         arch = property(lambda self: _join_arch(self.os, self.machine))
 288
 289 class Dependency(object):
 290         """A Dependency indicates that an Implementation requires some additional
 291         code to function. This is an abstract base class.
 292         @ivar metadata: any extra attributes from the XML element
 293         @type metadata: {str: str}
 294         """
 295         __slots__ = ['metadata']
 296
 297         def __init__(self, metadata):
 298                 if metadata is None:
 299                         metadata = {}
 300                 else:
 301                         assert not isinstance(metadata, basestring)     # Use InterfaceDependency instead!
 302                 self.metadata = metadata
 303
 304 class InterfaceDependency(Dependency):
 305         """A Dependency on a Zero Install interface.
 306         @ivar interface: the interface required by this dependency
 307         @type interface: str
 308         @ivar restrictions: a list of constraints on acceptable implementations
 309         @type restrictions: [L{Restriction}]
 310         @ivar bindings: how to make the choice of implementation known
 311         @type bindings: [L{Binding}]
 312         @since: 0.28
 313         """
 314         __slots__ = ['interface', 'restrictions', 'bindings', 'metadata']
 315
 316         def __init__(self, interface, restrictions = None, metadata = None):
 317                 Dependency.__init__(self, metadata)
 318                 assert isinstance(interface, (str, unicode))
 319                 assert interface
 320                 self.interface = interface
 321                 if restrictions is None:
 322                         self.restrictions = []
 323                 else:
 324                         self.restrictions = restrictions
 325                 self.bindings = []
 326
 327         def __str__(self):
 328                 return _("<Dependency on %(interface)s; bindings: %(bindings)s%(restrictions)s>") % {'interface': self.interface, 'bindings': self.bindings, 'restrictions': self.restrictions}
 329
 330 class RetrievalMethod(object):
 331         """A RetrievalMethod provides a way to fetch an implementation."""
 332         __slots__ = []
 333
 334 class DownloadSource(RetrievalMethod):
 335         """A DownloadSource provides a way to fetch an implementation."""
 336         __slots__ = ['implementation', 'url', 'size', 'extract', 'start_offset', 'type']
 337
 338         def __init__(self, implementation, url, size, extract, start_offset = 0, type = None):
 339                 self.implementation = implementation
 340                 self.url = url
 341                 self.size = size
 342                 self.extract = extract
 343                 self.start_offset = start_offset
 344                 self.type = type                # MIME type - see unpack.py
 345
 346 class Recipe(RetrievalMethod):
 347         """Get an implementation by following a series of steps.
 348         @ivar size: the combined download sizes from all the steps
 349         @type size: int
 350         @ivar steps: the sequence of steps which must be performed
 351         @type steps: [L{RetrievalMethod}]"""
 352         __slots__ = ['steps']
 353
 354         def __init__(self):
 355                 self.steps = []
 356
 357         size = property(lambda self: sum([x.size for x in self.steps]))
 358
 359 class Implementation(object):
 360         """An Implementation is a package which implements an Interface.
 361         @ivar download_sources: list of methods of getting this implementation
 362         @type download_sources: [L{RetrievalMethod}]
 363         @ivar feed: the feed owning this implementation (since 0.32)
 364         @type feed: [L{ZeroInstallFeed}]
 365         @ivar bindings: how to tell this component where it itself is located (since 0.31)
 366         @type bindings: [Binding]
 367         @ivar upstream_stability: the stability reported by the packager
 368         @type upstream_stability: [insecure | buggy | developer | testing | stable | packaged]
 369         @ivar user_stability: the stability as set by the user
 370         @type upstream_stability: [insecure | buggy | developer | testing | stable | packaged | preferred]
 371         @ivar langs: natural languages supported by this package
 372         @ivar requires: interfaces this package depends on
 373         @ivar main: the default file to execute when running as a program
 374         @ivar metadata: extra metadata from the feed
 375         @type metadata: {"[URI ]localName": str}
 376         @ivar id: a unique identifier for this Implementation
 377         @ivar version: a parsed version number
 378         @ivar released: release date
 379         """
 380
 381         # Note: user_stability shouldn't really be here
 382
 383         __slots__ = ['upstream_stability', 'user_stability', 'langs',
 384                      'requires', 'main', 'metadata', 'download_sources',
 385                      'id', 'feed', 'version', 'released', 'bindings', 'machine']
 386
 387         def __init__(self, feed, id):
 388                 assert id
 389                 self.feed = feed
 390                 self.id = id
 391                 self.main = None
 392                 self.user_stability = None
 393                 self.upstream_stability = None
 394                 self.metadata = {}      # [URI + " "] + localName -> value
 395                 self.requires = []
 396                 self.version = None
 397                 self.released = None
 398                 self.download_sources = []
 399                 self.langs = None
 400                 self.machine = None
 401                 self.bindings = []
 402
 403         def get_stability(self):
 404                 return self.user_stability or self.upstream_stability or testing
 405
 406         def __str__(self):
 407                 return self.id
 408
 409         def __repr__(self):
 410                 return "v%s (%s)" % (self.get_version(), self.id)
 411
 412         def __cmp__(self, other):
 413                 """Newer versions come first"""
 414                 return cmp(other.version, self.version)
 415
 416         def get_version(self):
 417                 """Return the version as a string.
 418                 @see: L{format_version}
 419                 """
 420                 return format_version(self.version)
 421
 422         arch = property(lambda self: _join_arch(self.os, self.machine))
 423
 424         os = None
 425
 426 class DistributionImplementation(Implementation):
 427         """An implementation provided by the distribution. Information such as the version
 428         comes from the package manager.
 429         @since: 0.28"""
 430         __slots__ = ['installed']
 431
 432         def __init__(self, feed, id):
 433                 assert id.startswith('package:')
 434                 Implementation.__init__(self, feed, id)
 435                 self.installed = True
 436
 437 class ZeroInstallImplementation(Implementation):
 438         """An implementation where all the information comes from Zero Install.
 439         @since: 0.28"""
 440         __slots__ = ['os', 'size']
 441
 442         def __init__(self, feed, id):
 443                 """id can be a local path (string starting with /) or a manifest hash (eg "sha1=XXX")"""
 444                 Implementation.__init__(self, feed, id)
 445                 self.size = None
 446                 self.os = None
 447
 448         # Deprecated
 449         dependencies = property(lambda self: dict([(x.interface, x) for x in self.requires
 450                                                    if isinstance(x, InterfaceDependency)]))
 451
 452         def add_download_source(self, url, size, extract, start_offset = 0, type = None):
 453                 """Add a download source."""
 454                 self.download_sources.append(DownloadSource(self, url, size, extract, start_offset, type))
 455
 456         def set_arch(self, arch):
 457                 self.os, self.machine = _split_arch(arch)
 458         arch = property(lambda self: _join_arch(self.os, self.machine), set_arch)
 459
 460 class Interface(object):
 461         """An Interface represents some contract of behaviour.
 462         @ivar uri: the URI for this interface.
 463         @ivar stability_policy: user's configured policy.
 464         Implementations at this level or higher are preferred.
 465         Lower levels are used only if there is no other choice.
 466         """
 467         __slots__ = ['uri', 'stability_policy', '_main_feed', 'extra_feeds']
 468
 469         implementations = property(lambda self: self._main_feed.implementations)
 470         name = property(lambda self: self._main_feed.name)
 471         description = property(lambda self: self._main_feed.description)
 472         summary = property(lambda self: self._main_feed.summary)
 473         last_modified = property(lambda self: self._main_feed.last_modified)
 474         feeds = property(lambda self: self.extra_feeds + self._main_feed.feeds)
 475         metadata = property(lambda self: self._main_feed.metadata)
 476
 477         last_checked = property(lambda self: self._main_feed.last_checked)
 478
 479         def __init__(self, uri):
 480                 assert uri
 481                 if uri.startswith('http:') or uri.startswith('/'):
 482                         self.uri = uri
 483                 else:
 484                         raise SafeException(_("Interface name '%s' doesn't start "
 485                                             "with 'http:'") % uri)
 486                 self.reset()
 487
 488         def _get_feed_for(self):
 489                 retval = {}
 490                 for key in self._main_feed.feed_for:
 491                         retval[key] = True
 492                 return retval
 493         feed_for = property(_get_feed_for)      # Deprecated (used by 0publish)
 494
 495         def reset(self):
 496                 self.extra_feeds = []
 497                 self._main_feed = _dummy_feed
 498                 self.stability_policy = None
 499
 500         def get_name(self):
 501                 if self._main_feed is not _dummy_feed:
 502                         return self._main_feed.get_name()
 503                 return '(' + os.path.basename(self.uri) + ')'
 504
 505         def __repr__(self):
 506                 return _("<Interface %s>") % self.uri
 507
 508         def set_stability_policy(self, new):
 509                 assert new is None or isinstance(new, Stability)
 510                 self.stability_policy = new
 511
 512         def get_feed(self, url):
 513                 for x in self.extra_feeds:
 514                         if x.uri == url:
 515                                 return x
 516                 return self._main_feed.get_feed(url)
 517
 518         def get_metadata(self, uri, name):
 519                 return self._main_feed.get_metadata(uri, name)
 520
 521 def _merge_attrs(attrs, item):
 522         """Add each attribute of item to a copy of attrs and return the copy.
 523         @type attrs: {str: str}
 524         @type item: L{qdom.Element}
 525         @rtype: {str: str}
 526         """
 527         new = attrs.copy()
 528         for a in item.attrs:
 529                 new[str(a)] = item.attrs[a]
 530         return new
 531
 532 def _get_long(elem, attr_name):
 533         val = elem.getAttribute(attr_name)
 534         if val is not None:
 535                 try:
 536                         val = long(val)
 537                 except ValueError, ex:
 538                         raise SafeException(_("Invalid value for integer attribute '%(attribute_name)s': %(value)s") % {'attribute_name': attr_name, 'value': val})
 539         return val
 540
 541 class ZeroInstallFeed(object):
 542         """A feed lists available implementations of an interface.
 543         @ivar url: the URL for this feed
 544         @ivar implementations: Implementations in this feed, indexed by ID
 545         @type implementations: {str: L{Implementation}}
 546         @ivar name: human-friendly name
 547         @ivar summary: short textual description
 548         @ivar description: long textual description
 549         @ivar last_modified: timestamp on signature
 550         @ivar last_checked: time feed was last successfully downloaded and updated
 551         @ivar feeds: list of <feed> elements in this feed
 552         @type feeds: [L{Feed}]
 553         @ivar feed_for: interfaces for which this could be a feed
 554         @type feed_for: set(str)
 555         @ivar metadata: extra elements we didn't understand
 556         """
 557         # _main is deprecated
 558         __slots__ = ['url', 'implementations', 'name', 'description', 'summary',
 559                      'last_checked', 'last_modified', 'feeds', 'feed_for', 'metadata']
 560
 561         def __init__(self, feed_element, local_path = None, distro = None):
 562                 """Create a feed object from a DOM.
 563                 @param feed_element: the root element of a feed file
 564                 @type feed_element: L{qdom.Element}
 565                 @param local_path: the pathname of this local feed, or None for remote feeds
 566                 @param distro: used to resolve distribution package references
 567                 @type distro: L{distro.Distribution} or None"""
 568                 assert feed_element
 569                 self.implementations = {}
 570                 self.name = None
 571                 self.summary = None
 572                 self.description = ""
 573                 self.last_modified = None
 574                 self.feeds = []
 575                 self.feed_for = set()
 576                 self.metadata = []
 577                 self.last_checked = None
 578
 579                 assert feed_element.name in ('interface', 'feed'), "Root element should be <interface>, not %s" % feed_element
 580                 assert feed_element.uri == XMLNS_IFACE, "Wrong namespace on root element: %s" % feed_element.uri
 581
 582                 main = feed_element.getAttribute('main')
 583                 #if main: warn("Setting 'main' on the root element is deprecated. Put it on a <group> instead")
 584
 585                 if local_path:
 586                         self.url = local_path
 587                         local_dir = os.path.dirname(local_path)
 588                 else:
 589                         self.url = feed_element.getAttribute('uri')
 590                         if not self.url:
 591                                 raise InvalidInterface(_("<interface> uri attribute missing"))
 592                         local_dir = None        # Can't have relative paths
 593
 594                 min_injector_version = feed_element.getAttribute('min-injector-version')
 595                 if min_injector_version:
 596                         if parse_version(min_injector_version) > parse_version(version):
 597                                 raise InvalidInterface(_("This feed requires version %(min_version)s or later of "
 598                                                         "Zero Install, but I am only version %(version)s. "
 599                                                         "You can get a newer version from http://0install.net") %
 600                                                         {'min_version': min_injector_version, 'version': version})
 601
 602                 for x in feed_element.childNodes:
 603                         if x.uri != XMLNS_IFACE:
 604                                 self.metadata.append(x)
 605                                 continue
 606                         if x.name == 'name':
 607                                 self.name = x.content
 608                         elif x.name == 'description':
 609                                 self.description = x.content
 610                         elif x.name == 'summary':
 611                                 self.summary = x.content
 612                         elif x.name == 'feed-for':
 613                                 feed_iface = x.getAttribute('interface')
 614                                 if not feed_iface:
 615                                         raise InvalidInterface(_('Missing "interface" attribute in <feed-for>'))
 616                                 self.feed_for.add(feed_iface)
 617                                 # Bug report from a Debian/stable user that --feed gets the wrong value.
 618                                 # Can't reproduce (even in a Debian/stable chroot), but add some logging here
 619                                 # in case it happens again.
 620                                 debug(_("Is feed-for %s"), feed_iface)
 621                         elif x.name == 'feed':
 622                                 feed_src = x.getAttribute('src')
 623                                 if not feed_src:
 624                                         raise InvalidInterface(_('Missing "src" attribute in <feed>'))
 625                                 if feed_src.startswith('http:') or local_path:
 626                                         self.feeds.append(Feed(feed_src, x.getAttribute('arch'), False, langs = x.getAttribute('langs')))
 627                                 else:
 628                                         raise InvalidInterface(_("Invalid feed URL '%s'") % feed_src)
 629                         else:
 630                                 self.metadata.append(x)
 631
 632                 if not self.name:
 633                         raise InvalidInterface(_("Missing <name> in feed"))
 634                 if not self.summary:
 635                         raise InvalidInterface(_("Missing <summary> in feed"))
 636
 637                 def process_group(group, group_attrs, base_depends, base_bindings):
 638                         for item in group.childNodes:
 639                                 if item.uri != XMLNS_IFACE: continue
 640
 641                                 if item.name not in ('group', 'implementation', 'package-implementation'):
 642                                         continue
 643
 644                                 depends = base_depends[:]
 645                                 bindings = base_bindings[:]
 646
 647                                 item_attrs = _merge_attrs(group_attrs, item)
 648
 649                                 # We've found a group or implementation. Scan for dependencies
 650                                 # and bindings. Doing this here means that:
 651                                 # - We can share the code for groups and implementations here.
 652                                 # - The order doesn't matter, because these get processed first.
 653                                 # A side-effect is that the document root cannot contain
 654                                 # these.
 655                                 for child in item.childNodes:
 656                                         if child.uri != XMLNS_IFACE: continue
 657                                         if child.name == 'requires':
 658                                                 dep = process_depends(child)
 659                                                 depends.append(dep)
 660                                         elif child.name in binding_names:
 661                                                 bindings.append(process_binding(child))
 662
 663                                 if item.name == 'group':
 664                                         process_group(item, item_attrs, depends, bindings)
 665                                 elif item.name == 'implementation':
 666                                         process_impl(item, item_attrs, depends, bindings)
 667                                 elif item.name == 'package-implementation':
 668                                         process_native_impl(item, item_attrs, depends)
 669                                 else:
 670                                         assert 0
 671
 672                 def process_impl(item, item_attrs, depends, bindings):
 673                         id = item.getAttribute('id')
 674                         if id is None:
 675                                 raise InvalidInterface(_("Missing 'id' attribute on %s") % item)
 676                         if local_dir and (id.startswith('/') or id.startswith('.')):
 677                                 impl = self._get_impl(os.path.abspath(os.path.join(local_dir, id)))
 678                         else:
 679                                 if '=' not in id:
 680                                         raise InvalidInterface(_('Invalid "id"; form is "alg=value" (got "%s")') % id)
 681                                 alg, sha1 = id.split('=')
 682                                 try:
 683                                         long(sha1, 16)
 684                                 except Exception, ex:
 685                                         raise InvalidInterface(_('Bad SHA1 attribute: %s') % ex)
 686                                 impl = self._get_impl(id)
 687
 688                         impl.metadata = item_attrs
 689                         try:
 690                                 version_mod = item_attrs.get('version-modifier', None)
 691                                 if version_mod:
 692                                         item_attrs['version'] += version_mod
 693                                         del item_attrs['version-modifier']
 694                                 version = item_attrs['version']
 695                         except KeyError:
 696                                 raise InvalidInterface(_("Missing version attribute"))
 697                         impl.version = parse_version(version)
 698
 699                         item_main = item_attrs.get('main', None)
 700                         if item_main and item_main.startswith('/'):
 701                                 raise InvalidInterface(_("'main' attribute must be relative, but '%s' starts with '/'!") %
 702                                                         item_main)
 703                         impl.main = item_main
 704
 705                         impl.released = item_attrs.get('released', None)
 706                         impl.langs = item_attrs.get('langs', None)
 707
 708                         size = item.getAttribute('size')
 709                         if size:
 710                                 impl.size = long(size)
 711                         impl.arch = item_attrs.get('arch', None)
 712                         try:
 713                                 stability = stability_levels[str(item_attrs['stability'])]
 714                         except KeyError:
 715                                 stab = str(item_attrs['stability'])
 716                                 if stab != stab.lower():
 717                                         raise InvalidInterface(_('Stability "%s" invalid - use lower case!') % item_attrs.stability)
 718                                 raise InvalidInterface(_('Stability "%s" invalid') % item_attrs['stability'])
 719                         if stability >= preferred:
 720                                 raise InvalidInterface(_("Upstream can't set stability to preferred!"))
 721                         impl.upstream_stability = stability
 722
 723                         impl.bindings = bindings
 724                         impl.requires = depends
 725
 726                         for elem in item.childNodes:
 727                                 if elem.uri != XMLNS_IFACE: continue
 728                                 if elem.name == 'archive':
 729                                         url = elem.getAttribute('href')
 730                                         if not url:
 731                                                 raise InvalidInterface(_("Missing href attribute on <archive>"))
 732                                         size = elem.getAttribute('size')
 733                                         if not size:
 734                                                 raise InvalidInterface(_("Missing size attribute on <archive>"))
 735                                         impl.add_download_source(url = url, size = long(size),
 736                                                         extract = elem.getAttribute('extract'),
 737                                                         start_offset = _get_long(elem, 'start-offset'),
 738                                                         type = elem.getAttribute('type'))
 739                                 elif elem.name == 'recipe':
 740                                         recipe = Recipe()
 741                                         for recipe_step in elem.childNodes:
 742                                                 if recipe_step.uri == XMLNS_IFACE and recipe_step.name == 'archive':
 743                                                         url = recipe_step.getAttribute('href')
 744                                                         if not url:
 745                                                                 raise InvalidInterface(_("Missing href attribute on <archive>"))
 746                                                         size = recipe_step.getAttribute('size')
 747                                                         if not size:
 748                                                                 raise InvalidInterface(_("Missing size attribute on <archive>"))
 749                                                         recipe.steps.append(DownloadSource(None, url = url, size = long(size),
 750                                                                         extract = recipe_step.getAttribute('extract'),
 751                                                                         start_offset = _get_long(recipe_step, 'start-offset'),
 752                                                                         type = recipe_step.getAttribute('type')))
 753                                                 else:
 754                                                         info(_("Unknown step '%s' in recipe; skipping recipe"), recipe_step.name)
 755                                                         break
 756                                         else:
 757                                                 impl.download_sources.append(recipe)
 758
 759                 def process_native_impl(item, item_attrs, depends):
 760                         package = item_attrs.get('package', None)
 761                         if package is None:
 762                                 raise InvalidInterface(_("Missing 'package' attribute on %s") % item)
 763
 764                         def factory(id):
 765                                 assert id.startswith('package:')
 766                                 impl = self._get_impl(id)
 767
 768                                 impl.metadata = item_attrs
 769
 770                                 item_main = item_attrs.get('main', None)
 771                                 if item_main and not item_main.startswith('/'):
 772                                         raise InvalidInterface(_("'main' attribute must be absolute, but '%s' doesn't start with '/'!") %
 773                                                                 item_main)
 774                                 impl.main = item_main
 775                                 impl.upstream_stability = packaged
 776                                 impl.requires = depends
 777
 778                                 return impl
 779
 780                         distro.get_package_info(package, factory)
 781
 782                 root_attrs = {'stability': 'testing'}
 783                 if main:
 784                         root_attrs['main'] = main
 785                 process_group(feed_element, root_attrs, [], [])
 786
 787         def get_name(self):
 788                 return self.name or '(' + os.path.basename(self.url) + ')'
 789
 790         def __repr__(self):
 791                 return _("<Feed %s>") % self.url
 792
 793         def _get_impl(self, id):
 794                 if id not in self.implementations:
 795                         if id.startswith('package:'):
 796                                 impl = DistributionImplementation(self, id)
 797                         else:
 798                                 impl = ZeroInstallImplementation(self, id)
 799                         self.implementations[id] = impl
 800                 return self.implementations[id]
 801
 802         def set_stability_policy(self, new):
 803                 assert new is None or isinstance(new, Stability)
 804                 self.stability_policy = new
 805
 806         def get_feed(self, url):
 807                 for x in self.feeds:
 808                         if x.uri == url:
 809                                 return x
 810                 return None
 811
 812         def add_metadata(self, elem):
 813                 self.metadata.append(elem)
 814
 815         def get_metadata(self, uri, name):
 816                 """Return a list of interface metadata elements with this name and namespace URI."""
 817                 return [m for m in self.metadata if m.name == name and m.uri == uri]
 818
 819 class DummyFeed(object):
 820         """Temporary class used during API transition."""
 821         last_modified = None
 822         name = '-'
 823         last_checked = property(lambda self: None)
 824         implementations = property(lambda self: {})
 825         feeds = property(lambda self: [])
 826         summary = property(lambda self: '-')
 827         description = property(lambda self: '')
 828         def get_name(self): return self.name
 829         def get_feed(self, url): return None
 830         def get_metadata(self, uri, name): return []
 831 _dummy_feed = DummyFeed()
 832
 833 def unescape(uri):
 834         """Convert each %20 to a space, etc.
 835         @rtype: str"""
 836         uri = uri.replace('#', '/')
 837         if '%' not in uri: return uri
 838         return re.sub('%[0-9a-fA-F][0-9a-fA-F]',
 839                 lambda match: chr(int(match.group(0)[1:], 16)),
 840                 uri).decode('utf-8')
 841
 842 def escape(uri):
 843         """Convert each space to %20, etc
 844         @rtype: str"""
 845         return re.sub('[^-_.a-zA-Z0-9]',
 846                 lambda match: '%%%02x' % ord(match.group(0)),
 847                 uri.encode('utf-8'))
 848
 849 def _pretty_escape(uri):
 850         """Convert each space to %20, etc
 851         : is preserved and / becomes #. This makes for nicer strings,
 852         and may replace L{escape} everywhere in future.
 853         @rtype: str"""
 854         return re.sub('[^-_.a-zA-Z0-9:/]',
 855                 lambda match: '%%%02x' % ord(match.group(0)),
 856                 uri.encode('utf-8')).replace('/', '#')
 857
 858 def canonical_iface_uri(uri):
 859         """If uri is a relative path, convert to an absolute one.
 860         A "file:///foo" URI is converted to "/foo".
 861         Otherwise, return it unmodified.
 862         @rtype: str
 863         @raise SafeException: if uri isn't valid
 864         """
 865         if uri.startswith('http://'):
 866                 if uri.find("/", 7) == -1:
 867                         raise SafeException(_("Missing / after hostname in URI '%s'") % uri)
 868                 return uri
 869         elif uri.startswith('file:///'):
 870                 return uri[7:]
 871         else:
 872                 iface_uri = os.path.realpath(uri)
 873                 if os.path.isfile(iface_uri):
 874                         return iface_uri
 875         raise SafeException(_("Bad interface name '%(uri)s'.\n"
 876                         "(doesn't start with 'http:', and "
 877                         "doesn't exist as a local file '%(interface_uri)s' either)") %
 878                         {'uri': uri, 'interface_uri': iface_uri})
 879
 880 _version_mod_to_value = {
 881         'pre': -2,
 882         'rc': -1,
 883         '': 0,
 884         'post': 1,
 885 }
 886
 887 # Reverse mapping
 888 _version_value_to_mod = {}
 889 for x in _version_mod_to_value: _version_value_to_mod[_version_mod_to_value[x]] = x
 890 del x
 891
 892 _version_re = re.compile('-([a-z]*)')
 893
 894 def parse_version(version_string):
 895         """Convert a version string to an internal representation.
 896         The parsed format can be compared quickly using the standard Python functions.
 897          - Version := DottedList ("-" Mod DottedList?)*
 898          - DottedList := (Integer ("." Integer)*)
 899         @rtype: tuple (opaque)
 900         @raise SafeException: if the string isn't a valid version
 901         @since: 0.24 (moved from L{reader}, from where it is still available):"""
 902         if version_string is None: return None
 903         parts = _version_re.split(version_string)
 904         if parts[-1] == '':
 905                 del parts[-1]   # Ends with a modifier
 906         else:
 907                 parts.append('')
 908         if not parts:
 909                 raise SafeException(_("Empty version string!"))
 910         l = len(parts)
 911         try:
 912                 for x in range(0, l, 2):
 913                         part = parts[x]
 914                         if part:
 915                                 parts[x] = map(int, parts[x].split('.'))
 916                         else:
 917                                 parts[x] = []   # (because ''.split('.') == [''], not [])
 918                 for x in range(1, l, 2):
 919                         parts[x] = _version_mod_to_value[parts[x]]
 920                 return parts
 921         except ValueError, ex:
 922                 raise SafeException(_("Invalid version format in '%(version_string)s': %(exception)s") % {'version_string': version_string, 'exception': ex})
 923         except KeyError, ex:
 924                 raise SafeException(_("Invalid version modifier in '%(version_string)s': %(exception)s") % {'version_string': version_string, 'exception': ex})
 925
 926 def format_version(version):
 927         """Format a parsed version for display. Undoes the effect of L{parse_version}.
 928         @see: L{Implementation.get_version}
 929         @rtype: str
 930         @since: 0.24"""
 931         version = version[:]
 932         l = len(version)
 933         for x in range(0, l, 2):
 934                 version[x] = '.'.join(map(str, version[x]))
 935         for x in range(1, l, 2):
 936                 version[x] = '-' + _version_value_to_mod[version[x]]
 937         if version[-1] == '-': del version[-1]
 938         return ''.join(version)
 939