pgraph: Fix race condition when destructing/constructing NodePaths

Fixes #1366
This commit is contained in:
rdb 2022-10-22 15:36:14 +02:00
parent 00de2771fc
commit 8bed85740f

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@ -2898,11 +2898,21 @@ get_component(NodePathComponent *parent, PandaNode *child_node,
// First, walk through the list of NodePathComponents we already have on the
// child, looking for one that already exists, referencing the indicated
// parent component.
Paths::const_iterator pi;
for (pi = child_node->_paths.begin(); pi != child_node->_paths.end(); ++pi) {
if ((*pi)->get_next(pipeline_stage, current_thread) == parent) {
for (NodePathComponent *child : child_node->_paths) {
if (child->get_next(pipeline_stage, current_thread) == parent) {
// If we already have such a component, just return it.
return (*pi);
// But before we do, we have to make sure it's not in the middle of being
// destructed.
#ifdef HAVE_THREADS
if (child->ref_if_nonzero()) {
PT(NodePathComponent) result;
result.cheat() = child;
return result;
}
#else
// If we're not building with threading, increment as normal.
return child;
#endif
}
}
@ -2940,11 +2950,21 @@ get_top_component(PandaNode *child_node, bool force, int pipeline_stage,
// Walk through the list of NodePathComponents we already have on the child,
// looking for one that already exists as a top node.
Paths::const_iterator pi;
for (pi = child_node->_paths.begin(); pi != child_node->_paths.end(); ++pi) {
if ((*pi)->is_top_node(pipeline_stage, current_thread)) {
for (NodePathComponent *child : child_node->_paths) {
if (child->is_top_node(pipeline_stage, current_thread)) {
// If we already have such a component, just return it.
return (*pi);
// But before we do, we have to make sure it's not in the middle of being
// destructed.
#ifdef HAVE_THREADS
if (child->ref_if_nonzero()) {
PT(NodePathComponent) result;
result.cheat() = child;
return result;
}
#else
// If we're not building with threading, increment as normal.
return child;
#endif
}
}