python: Make all CppOwnedPyObjects and similar support garbage collection.

If you want to subclass apt_pkg.Cache() and create an apt_pkg.DepCache()
object in it (e.g. as self.depcache) this is needed because otherwise,
Python would not know about the cyclic dependency and refuse to free any
of them.

This also changes apt_pkg.Cache to the standard deallocation schema,
because the underlying CacheFile deletes its pointers automatically on
deletion. Thus a second call is not needed.

1 files changed, 4 insertions, 3 deletions

diff --git a/python/acquire.cc b/python/acquire.cc
index 704ad0bd..b0dd2cab 100644
--- a/python/acquire.cc
+++ b/python/acquire.cc
@@ -372,10 +372,11 @@ PyTypeObject PkgAcquireFileType =
    0,                                   // tp_setattro
    0,                                   // tp_as_buffer
    (Py_TPFLAGS_DEFAULT |                // tp_flags
-    Py_TPFLAGS_BASETYPE),
+    Py_TPFLAGS_BASETYPE |
+    Py_TPFLAGS_HAVE_GC),
    doc_PkgAcquireFile,                  // tp_doc
-   0,                                   // tp_traverse
-   0,                                   // tp_clear
+   CppOwnedTraverse<pkgAcqFile*>,       // tp_traverse
+   CppOwnedClear<pkgAcqFile*>,          // tp_clear
    0,                                   // tp_richcompare
    0,                                   // tp_weaklistoffset
    0,                                   // tp_iter