1 files changed, 34 insertions, 33 deletions

diff --git a/apt/cache.py b/apt/cache.py
index c8615caf..e716d9e6 100644
--- a/apt/cache.py
+++ b/apt/cache.py
@@ -27,7 +27,6 @@ import weakref
 
 import apt_pkg
 from apt import Package
-from apt_pkg import gettext as _
 import apt.progress.text
 
 
@@ -73,8 +72,6 @@ class Cache(object):
         self._list = None
         self._callbacks = {}
         self._weakref = weakref.WeakValueDictionary()
-        self._set = set()
-        self._fullnameset = set()
         self._changes_count = -1
         self._sorted_set = None
 
@@ -156,28 +153,11 @@ class Cache(object):
         self._records = apt_pkg.PackageRecords(self._cache)
         self._list = apt_pkg.SourceList()
         self._list.read_main_list()
-        self._set.clear()
-        self._fullnameset.clear()
         self._sorted_set = None
         self._weakref.clear()
 
         self._have_multi_arch = len(apt_pkg.get_architectures()) > 1
 
-        progress.op = _("Building data structures")
-        i = last = 0
-        size = len(self._cache.packages)
-        for pkg in self._cache.packages:
-            if progress is not None and last + 100 < i:
-                progress.update(i / float(size) * 100)
-                last = i
-            # drop stuff with no versions (cruft)
-            if pkg.has_versions:
-                self._set.add(pkg.get_fullname(pretty=True))
-                if self._have_multi_arch:
-                    self._fullnameset.add(pkg.get_fullname(pretty=False))
-
-            i += 1
-
         progress.done()
         self._run_callbacks("cache_post_open")
 
@@ -200,37 +180,58 @@ class Cache(object):
         try:
             return self._weakref[key]
         except KeyError:
-            if key in self._set or key in self._fullnameset:
-                key = str(key)
-                pkg = self._weakref[key] = Package(self, self._cache[key])
-                return pkg
-            else:
+            key = str(key)
+            try:
+                rawpkg = self._cache[key]
+            except KeyError:
                 raise KeyError('The cache has no package named %r' % key)
 
+            # It might be excluded due to not having a version or something
+            if not self.__is_real_pkg(rawpkg):
+                raise KeyError('The cache has no package named %r' % key)
+
+            # Check if we already know the package using the normalized name
+            name = rawpkg.get_fullname(pretty=False)
+            try:
+                return self._weakref[name]
+            except KeyError:
+                pkg = Package(self, rawpkg)
+                self._weakref[key] = self._weakref[name] = pkg
+
+            return pkg
+
     def __iter__(self):
         # We iterate sorted over package names here. With this we read the
         # package lists linearly if we need to access the package records,
         # instead of having to do thousands of random seeks; the latter
         # is disastrous if we use compressed package indexes, and slower than
         # necessary for uncompressed indexes.
-        if self._sorted_set is None:
-            self._sorted_set = sorted(self._set)
-
-        for pkgname in self._sorted_set:
+        for pkgname in self.keys():
             yield self[pkgname]
         raise StopIteration
 
+    def __is_real_pkg(self, rawpkg):
+        """Check if the apt_pkg.Package provided is a real package."""
+        return rawpkg.has_versions
+
     def has_key(self, key):
-        return (key in self._set or key in self._fullnameset)
+        return key in self
 
     def __contains__(self, key):
-        return (key in self._set or key in self._fullnameset)
+        try:
+            return self.__is_real_pkg(self._cache[key])
+        except KeyError:
+            return False
 
     def __len__(self):
-        return len(self._set)
+        return len(self.keys())
 
     def keys(self):
-        return list(self._set)
+        if self._sorted_set is None:
+            self._sorted_set = sorted(p.get_fullname(pretty=True)
+                                      for p in self._cache.packages
+                                        if self.__is_real_pkg(p))
+        return list(self._sorted_set)  # We need a copy here, caller may modify
 
     def get_changes(self):
         """ Get the marked changes """