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