1 files changed, 49 insertions, 0 deletions
diff --git a/apt/cache.py b/apt/cache.py
index bbf2165b..3fd1e996 100644
--- a/apt/cache.py
+++ b/apt/cache.py
@@ -182,6 +182,51 @@ class Cache(object):
         finally:
             os.close(lock)
 
+    def isVirtualPackage(self, name):
+        """ 
+        Return True if the package of the given name is a virtual package
+        """
+        try:
+            virtual_pkg = self._cache[name]
+        except KeyError:
+            return False
+        if len(virtual_pkg.VersionList) == 0:
+            return True
+        return False
+
+    def getProvidingPackages(self, virtual):
+        """
+        Return a list of packages which provide the virtual package of the
+        specified name
+        """
+        providers = []
+        try:
+            vp = self._cache[virtual]
+            if len(vp.VersionList) != 0:
+                return providers
+        except KeyError:
+            return providers
+        for pkg in self:
+            v = self._depcache.GetCandidateVer(pkg._pkg)
+            if v == None:
+                continue
+            for p in v.ProvidesList:
+                #print virtual
+                #print p[0]
+                if virtual == p[0]:
+                    # we found a pkg that provides this virtual
+                    # pkg, check if the proivdes is any good
+                    providers.append(pkg)
+                    #cand = self._cache[pkg.name]
+                    #candver = self._cache._depcache.GetCandidateVer(cand._pkg)
+                    #instver = cand._pkg.CurrentVer
+                    #res = apt_pkg.CheckDep(candver.VerStr,oper,ver)
+                    #if res == True:
+                    #    self._dbg(1,"we can use %s" % pkg.name)
+                    #    or_found = True
+                    #    break
+        return providers
+
     def update(self, fetchProgress=None):
         " run the equivalent of apt-get update "
         lockfile = apt_pkg.Config.FindDir("Dir::State::Lists") + "lock"
@@ -232,6 +277,10 @@ class Cache(object):
             fetcher.Shutdown()
         return (res == pm.ResultCompleted)
 
+    def clear(self):
+         """ Unmark all changes """
+         self._depcache.Init()
+
     # cache changes
     def cachePostChange(self):
         " called internally if the cache has changed, emit a signal then "