From bf4dc1cd37acfdf32c9d70531914bd58f06bbd84 Mon Sep 17 00:00:00 2001
From: Fabio Erculiani <lxnay@sabayon.org>
Date: Fri, 11 Feb 2011 19:06:22 +0100
Subject: [PATCH] [entropy.graph] implement Graph.destroy() to free circular
 references (was causing interesting memleak)

---
 client/text_query.py                       |  2 +
 libraries/entropy/client/interfaces/dep.py |  5 ++
 libraries/entropy/graph.py                 | 75 ++++++++++++++++++++++
 3 files changed, 82 insertions(+)

diff --git a/client/text_query.py b/client/text_query.py
index 4ccb53d08..dba292c03 100644
--- a/client/text_query.py
+++ b/client/text_query.py
@@ -385,6 +385,7 @@ def _revgraph_package(installed_pkg_id, package, dbconn, show_complete = False):
         _show_graph_legend()
 
     del stack
+    graph.destroy()
     del graph
     return 0
 
@@ -471,6 +472,7 @@ def _graph_package(match, package, entropy_intf, show_complete = False):
         _show_dependencies_legend()
 
     del stack
+    graph.destroy()
     del graph
     return 0
 
diff --git a/libraries/entropy/client/interfaces/dep.py b/libraries/entropy/client/interfaces/dep.py
index 182453f3e..0aee6a778 100644
--- a/libraries/entropy/client/interfaces/dep.py
+++ b/libraries/entropy/client/interfaces/dep.py
@@ -1334,12 +1334,14 @@ class CalculatorsMixin:
             deptree_conflicts |= conflicts
 
         if deps_not_found:
+            graph.destroy()
             del graph
             raise DependenciesNotFound(deps_not_found)
 
         # solve depgraph and append conflicts
         deptree = graph.solve()
         if 0 in deptree:
+            graph.destroy()
             del graph
             raise KeyError("Graph contains a dep_level == 0")
 
@@ -1354,6 +1356,7 @@ class CalculatorsMixin:
         _colliding_deps = [x for x in _dup_deps_collisions.values() if \
             len(x) > 1]
         if _colliding_deps:
+            graph.destroy()
             del graph
             raise DependenciesCollision(_colliding_deps)
 
@@ -1364,6 +1367,7 @@ class CalculatorsMixin:
             level_count += 1
             reverse_tree[level_count] = deptree[key]
 
+        graph.destroy()
         del deptree, graph
         reverse_tree[0] = deptree_conflicts
 
@@ -1660,6 +1664,7 @@ class CalculatorsMixin:
             deptree = graph.solve()
             del flat_dep_tree
 
+        graph.destroy()
         del graph
 
         if self.xcache:
diff --git a/libraries/entropy/graph.py b/libraries/entropy/graph.py
index 0465b795f..ae1308db5 100644
--- a/libraries/entropy/graph.py
+++ b/libraries/entropy/graph.py
@@ -35,6 +35,25 @@ class GraphNode(object):
         self.__item = item
         self.__arches = set()
 
+    def __del__(self):
+        try:
+            self._clear()
+        except (NameError, AttributeError):
+            pass
+
+    def _clear(self):
+        """
+        Clear the object
+        """
+        try:
+            self.__arches.clear()
+        except (NameError, AttributeError):
+            pass
+        try:
+            self.__item = None
+        except (NameError, AttributeError):
+            pass
+
     def __str__(self):
         """
         Default string representation.
@@ -135,6 +154,22 @@ class GraphArchSet(object):
         self.__origin = starting_point
         self.__endpoints = set()
 
+    def __del__(self):
+        try:
+            self._clear()
+        except (NameError, AttributeError):
+            pass
+
+    def _clear(self):
+        """
+        Cleanup the object
+        """
+        try:
+            self.__endpoints.clear()
+            del self.__origin
+        except (NameError, AttributeError):
+            pass
+
     def __str__(self):
         """
         Default string representation.
@@ -210,6 +245,16 @@ class TopologicalSorter(object):
         self.__adjacency_map = adjacency_map
         self.__stack = Lifo()
 
+    def __del__(self):
+        try:
+            self.__adjacency_map.clear()
+        except (NameError, AttributeError):
+            pass
+        try:
+            self.__stack.clear()
+        except (NameError, AttributeError):
+            pass
+
     def __topological_sort_visit_node(self, node, low, result):
         """
         Internal method, visits a node ad push to stack.
@@ -340,6 +385,36 @@ class Graph(object):
         self.__archs_map = {}
         self.__graph_map_cache = None
 
+    def __del__(self):
+        try:
+            self.destroy()
+        except (AttributeError, NameError):
+            pass
+
+    def destroy(self):
+        """
+        Cleanup any reference.
+        """
+        try:
+            for obj in self.__graph.values():
+                obj._clear()
+            self.__graph.clear()
+        except (NameError, AttributeError):
+            pass
+        try:
+            for obj in self.__archs_map.values():
+                obj._clear()
+            self.__archs_map.clear()
+        except (NameError, AttributeError):
+            pass
+        try:
+            if self.__graph_map_cache is not None:
+                for obj in self.__graph_map_cache.values():
+                    obj._clear()
+                self.__graph_map_cache.clear()
+        except (NameError, AttributeError):
+            pass
+
     def __invalidate_cache(self):
         """
         Private method, stay away from here.