Implement lazy construction of global databases db[root]["porttree"] and db[root...

db[root]["bintree"] on access.

svn path=/main/trunk/; revision=3127

diff --git a/pym/portage.py b/pym/portage.py
index 0b815fed6ebc4c8252a0dc0714297482607441d8..d58d9a968a9933a8c3d7a7412b769cbd09aebcd9 100644 (file)
--- a/pym/portage.py
+++ b/pym/portage.py
@@ -6804,11 +6804,34 @@ if (secpass==2) and (not os.environ.has_key("SANDBOX_ACTIVE")):
                global_updates()
 
 #continue setting up other trees
-db["/"]["porttree"] = portagetree("/")
-db["/"]["bintree"] = binarytree("/", settings["PKGDIR"])
+class LazyDatabasesDict(dict):
+       """This class implements lazy construction of the global databases
+       db[root]["porttree"] and db[root]["bintree"]."""
+       def __init__(self, myroot, items):
+               dict.__init__(self)
+               self.update(items)
+               self.myroot = myroot
+               self.lazy_keys = ("porttree", "bintree")
+               for x in self.lazy_keys:
+                       self[x] = None
+       def __getitem__(self, item_key):
+               if item_key in self.lazy_keys and item_key in self:
+                       myvalue = dict.__getitem__(self, item_key)
+                       if myvalue is None:
+                               if "porttree" == item_key:
+                                       myvalue = portagetree(self.myroot)
+                               elif "bintree" == item_key:
+                                       global settings
+                                       myvalue = binarytree(self.myroot, settings["PKGDIR"])
+                                       # The binarytree likely needs to be populated now, so we
+                                       # do it now to make sure that all method calls are safe.
+                                       myvalue.populate()
+                       return myvalue
+               return dict.__getitem__(self, item_key)
+
+db["/"] = LazyDatabasesDict("/", db["/"])
 if root!="/":
-       db[root]["porttree"] = portagetree(root)
-       db[root]["bintree"] = binarytree(root, settings["PKGDIR"])
+       db[root] = LazyDatabasesDict(root, db[root])
 
 profileroots = [settings["PORTDIR"]+"/profiles/"]
 for x in settings["PORTDIR_OVERLAY"].split():