From e435461e9a993a08a18b83ed86cac882553c57fe Mon Sep 17 00:00:00 2001
From: David Cattermole <cattermole91@gmail.com>
Date: Sun, 4 Jul 2021 13:42:09 +0100
Subject: [PATCH] Trigger event to close all windows when opening a new Maya
 scene file.

This stops crashes from happening caused when opening a new Maya scene
while the window(s) (internally) still hold a pointer to some
deallocated memory (from the previously open Maya scene).

Closing all windows clears the memory and fixes the problem.

Issue #222.
---
 python/mmSolver/_api/constant.py             |  2 ++
 python/mmSolver/api.py                       |  2 ++
 python/mmSolver/tools/registerevents/lib.py  | 14 +++++++++++
 python/mmSolver/tools/registerevents/tool.py | 25 ++++++++++++++++++++
 4 files changed, 43 insertions(+)

diff --git a/python/mmSolver/_api/constant.py b/python/mmSolver/_api/constant.py
index 9d7c2ff6f..b45ae7f5a 100644
--- a/python/mmSolver/_api/constant.py
+++ b/python/mmSolver/_api/constant.py
@@ -224,6 +224,7 @@
 EVENT_NAME_NODE_NAME_CHANGED = 'node_name_changed'
 EVENT_NAME_NODE_DELETED = 'node_deleted'
 EVENT_NAME_MEMBERSHIP_CHANGED = 'node_membership_changed'
+EVENT_NAME_MAYA_SCENE_CLOSING = 'maya_scene_closing'
 EVENT_NAME_LIST = [
     EVENT_NAME_MARKER_CREATED,
     EVENT_NAME_BUNDLE_CREATED,
@@ -235,6 +236,7 @@
     EVENT_NAME_NODE_NAME_CHANGED,
     EVENT_NAME_NODE_DELETED,
     EVENT_NAME_MEMBERSHIP_CHANGED,
+    EVENT_NAME_MAYA_SCENE_CLOSING,
 ]
 
 
diff --git a/python/mmSolver/api.py b/python/mmSolver/api.py
index 37911d4e2..5b8b4f03d 100644
--- a/python/mmSolver/api.py
+++ b/python/mmSolver/api.py
@@ -185,6 +185,7 @@
     EVENT_NAME_NODE_NAME_CHANGED,
     EVENT_NAME_NODE_DELETED,
     EVENT_NAME_MEMBERSHIP_CHANGED,
+    EVENT_NAME_MAYA_SCENE_CLOSING,
     EVENT_NAME_LIST,
 
     ATTRIBUTE_USED_HINT_DEFAULT_VALUE,
@@ -303,6 +304,7 @@
     'EVENT_NAME_NODE_NAME_CHANGED',
     'EVENT_NAME_NODE_DELETED',
     'EVENT_NAME_MEMBERSHIP_CHANGED',
+    'EVENT_NAME_MAYA_SCENE_CLOSING',
     'EVENT_NAME_LIST',
     'ATTRIBUTE_USED_HINT_DEFAULT_VALUE',
     'ATTRIBUTE_USED_HINT_USED_VALUE',
diff --git a/python/mmSolver/tools/registerevents/lib.py b/python/mmSolver/tools/registerevents/lib.py
index 790647ce9..b7f93764e 100644
--- a/python/mmSolver/tools/registerevents/lib.py
+++ b/python/mmSolver/tools/registerevents/lib.py
@@ -84,3 +84,17 @@ def run_update_output_attributes_in_solver_ui(**kwargs):
     e = time.time()
     LOG.debug("run_update_output_attributes_in_solver_ui: time=%s", e - s)
     return
+
+
+def run_close_all_windows(**kwargs):
+    """
+    Find and close all tool UIs sub-classed from BaseMayaWindow.
+    """
+    LOG.debug("run_close_all_windows: %r", kwargs)
+    s = time.time()
+    import mmSolver.ui.base_maya_window
+    cls = mmSolver.ui.base_maya_window.BaseMayaWindow
+    cls.close_all_instances()
+    e = time.time()
+    LOG.debug("run_close_all_windows: time=%s", e - s)
+    return
diff --git a/python/mmSolver/tools/registerevents/tool.py b/python/mmSolver/tools/registerevents/tool.py
index e4a3ce48a..d18c94590 100644
--- a/python/mmSolver/tools/registerevents/tool.py
+++ b/python/mmSolver/tools/registerevents/tool.py
@@ -79,6 +79,19 @@ def _register_changed_attribute_update_solver_ui():
     return
 
 
+def _register_closing_maya_scene():
+    """When the current Maya scene is closing, close all windows, because
+    the windows might have pointers/references to objects in the scene
+    file and we cannot allow the pointers to dangle.
+    """
+    import mmSolver.api as mmapi
+    event_utils.add_function_to_event(
+        mmapi.EVENT_NAME_MAYA_SCENE_CLOSING,
+        lib.run_close_all_windows,
+        deferred=False)
+    return
+
+
 def register_events():
     """
     Initialises the registry of events for mmSolver.
@@ -90,4 +103,16 @@ def register_events():
     _register_created_marker_connect_to_collection()
     _register_changed_collection_update_solver_ui()
     _register_changed_attribute_update_solver_ui()
+    _register_closing_maya_scene()
+
+    # Maya callback when Maya scene is "flushing" from memory ( AKA
+    # the scene is closing).
+    def flushing_scene_func():
+        LOG.debug('MM Solver Flushing Scene...')
+        event_name = mmapi.EVENT_NAME_MAYA_SCENE_CLOSING
+        event_utils.trigger_event(event_name)
+
+    import maya.cmds
+    maya.cmds.scriptJob(
+        conditionTrue=('flushingScene', flushing_scene_func))
     return