src/allmydata/nodemaker.py

   1 import weakref
   2 from zope.interface import implements
   3 from allmydata.util.assertutil import precondition
   4 from allmydata.interfaces import INodeMaker, NotDeepImmutableError
   5 from allmydata.immutable.filenode import ImmutableFileNode, LiteralFileNode
   6 from allmydata.immutable.upload import Data
   7 from allmydata.mutable.filenode import MutableFileNode
   8 from allmydata.dirnode import DirectoryNode, pack_children
   9 from allmydata.unknown import UnknownNode
  10 from allmydata import uri
  11
  12 class DummyImmutableFileNode:
  13     def get_writekey(self):
  14         return None
  15
  16 class NodeMaker:
  17     implements(INodeMaker)
  18
  19     def __init__(self, storage_broker, secret_holder, history,
  20                  uploader, downloader, download_cache_dirman,
  21                  default_encoding_parameters, key_generator):
  22         self.storage_broker = storage_broker
  23         self.secret_holder = secret_holder
  24         self.history = history
  25         self.uploader = uploader
  26         self.downloader = downloader
  27         self.download_cache_dirman = download_cache_dirman
  28         self.default_encoding_parameters = default_encoding_parameters
  29         self.key_generator = key_generator
  30
  31         self._node_cache = weakref.WeakValueDictionary() # uri -> node
  32
  33     def _create_lit(self, cap):
  34         return LiteralFileNode(cap)
  35     def _create_immutable(self, cap):
  36         return ImmutableFileNode(cap, self.storage_broker, self.secret_holder,
  37                                  self.downloader, self.history,
  38                                  self.download_cache_dirman)
  39     def _create_mutable(self, cap):
  40         n = MutableFileNode(self.storage_broker, self.secret_holder,
  41                             self.default_encoding_parameters,
  42                             self.history)
  43         return n.init_from_cap(cap)
  44     def _create_dirnode(self, filenode):
  45         return DirectoryNode(filenode, self, self.uploader)
  46
  47     def create_from_cap(self, writecap, readcap=None):
  48         # this returns synchronously. It starts with a "cap string".
  49         assert isinstance(writecap, (str, type(None))), type(writecap)
  50         assert isinstance(readcap,  (str, type(None))), type(readcap)
  51         bigcap = writecap or readcap
  52         if not bigcap:
  53             # maybe the writecap was hidden because we're in a readonly
  54             # directory, and the future cap format doesn't have a readcap, or
  55             # something.
  56             return UnknownNode(writecap, readcap)
  57         if bigcap in self._node_cache:
  58             return self._node_cache[bigcap]
  59         cap = uri.from_string(bigcap)
  60         node = self._create_from_cap(cap)
  61         if node:
  62             self._node_cache[bigcap] = node  # note: WeakValueDictionary
  63         else:
  64             node = UnknownNode(writecap, readcap) # don't cache UnknownNode
  65         return node
  66
  67     def _create_from_cap(self, cap):
  68         # This starts with a "cap instance"
  69         if isinstance(cap, uri.LiteralFileURI):
  70             return self._create_lit(cap)
  71         if isinstance(cap, uri.CHKFileURI):
  72             return self._create_immutable(cap)
  73         if isinstance(cap, (uri.ReadonlySSKFileURI, uri.WriteableSSKFileURI)):
  74             return self._create_mutable(cap)
  75         if isinstance(cap, (uri.DirectoryURI,
  76                             uri.ReadonlyDirectoryURI,
  77                             uri.ImmutableDirectoryURI,
  78                             uri.LiteralDirectoryURI)):
  79             filenode = self._create_from_cap(cap.get_filenode_cap())
  80             return self._create_dirnode(filenode)
  81         return None
  82
  83     def create_mutable_file(self, contents=None, keysize=None):
  84         n = MutableFileNode(self.storage_broker, self.secret_holder,
  85                             self.default_encoding_parameters, self.history)
  86         d = self.key_generator.generate(keysize)
  87         d.addCallback(n.create_with_keys, contents)
  88         d.addCallback(lambda res: n)
  89         return d
  90
  91     def create_new_mutable_directory(self, initial_children={}):
  92         # initial_children must have metadata (i.e. {} instead of None), and
  93         # should not contain UnknownNodes
  94         for (name, (node, metadata)) in initial_children.iteritems():
  95             precondition(not isinstance(node, UnknownNode),
  96                          "create_new_mutable_directory does not accept UnknownNode", node)
  97             precondition(isinstance(metadata, dict),
  98                          "create_new_mutable_directory requires metadata to be a dict, not None", metadata)
  99         d = self.create_mutable_file(lambda n:
 100                                      pack_children(n, initial_children))
 101         d.addCallback(self._create_dirnode)
 102         return d
 103
 104     def create_immutable_directory(self, children, convergence=None):
 105         if convergence is None:
 106             convergence = self.secret_holder.get_convergence_secret()
 107         for (name, (node, metadata)) in children.iteritems():
 108             precondition(not isinstance(node, UnknownNode),
 109                          "create_immutable_directory does not accept UnknownNode", node)
 110             precondition(isinstance(metadata, dict),
 111                          "create_immutable_directory requires metadata to be a dict, not None", metadata)
 112             if node.is_mutable():
 113                 raise NotDeepImmutableError("%s is not immutable" % (node,))
 114         n = DummyImmutableFileNode() # writekey=None
 115         packed = pack_children(n, children)
 116         uploadable = Data(packed, convergence)
 117         d = self.uploader.upload(uploadable, history=self.history)
 118         def _uploaded(results):
 119             filecap = self.create_from_cap(results.uri)
 120             return filecap
 121         d.addCallback(_uploaded)
 122         d.addCallback(self._create_dirnode)
 123         return d