From b598e229403a7b9a6f972608e913245604a6172d Mon Sep 17 00:00:00 2001
From: aloysb <aloysb@al.com.au>
Date: Mon, 14 Sep 2020 10:02:40 +1000
Subject: [PATCH 1/2] Cache the LayerManager node to avoid very expensive maya
 query when starting editing

---
 .../lib/AL_USDMaya/AL/usdmaya/nodes/LayerManager.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/LayerManager.cpp b/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/LayerManager.cpp
index 93eb008d0f..2d4e4d62e8 100644
--- a/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/LayerManager.cpp
+++ b/plugin/al/lib/AL_USDMaya/AL/usdmaya/nodes/LayerManager.cpp
@@ -29,6 +29,7 @@
 #include <maya/MFnDependencyNode.h>
 #include <maya/MGlobal.h>
 #include <maya/MItDependencyNodes.h>
+#include <maya/MObjectHandle.h>
 #include <maya/MPlugArray.h>
 #include <maya/MProfiler.h>
 
@@ -43,6 +44,9 @@ const int _layerManagerProfilerCategory = MProfiler::addCategory(
     "LayerManager"
 #endif
 );
+
+MObjectHandle theLayerManagerHandle;
+
 } // namespace
 
 namespace {
@@ -299,12 +303,20 @@ MObject LayerManager::findNode()
 //----------------------------------------------------------------------------------------------------------------------
 MObject LayerManager::_findNode()
 {
+    if (theLayerManagerHandle.isValid() && theLayerManagerHandle.isAlive()) {
+        MObject theManager { theLayerManagerHandle.object() };
+        if (!theManager.isNull()) {
+            return theManager;
+        }
+    }
+
     MFnDependencyNode  fn;
     MItDependencyNodes iter(MFn::kPluginDependNode);
     for (; !iter.isDone(); iter.next()) {
         MObject mobj = iter.item();
         fn.setObject(mobj);
         if (fn.typeId() == kTypeId && !fn.isFromReferencedFile()) {
+            theLayerManagerHandle = mobj;
             return mobj;
         }
     }

From 831f3afaa491e4ba76d5e1825ec30c5b0872a191 Mon Sep 17 00:00:00 2001
From: Jonathan Moallem <jonathanm@al.com.au>
Date: Fri, 15 Oct 2021 11:00:21 +1100
Subject: [PATCH 2/2] Added caching of LayerManager on findNode

---
 lib/mayaUsd/nodes/layerManager.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/mayaUsd/nodes/layerManager.cpp b/lib/mayaUsd/nodes/layerManager.cpp
index 51228ee010..b79fb6fa6d 100644
--- a/lib/mayaUsd/nodes/layerManager.cpp
+++ b/lib/mayaUsd/nodes/layerManager.cpp
@@ -136,12 +136,23 @@ getFileFormatForLayer(const std::string& identifierVal, const std::string& seria
 
 MayaUsd::LayerManager* findNode()
 {
-    MFnDependencyNode  fn;
+    // Check for cached layer manager before searching
+    MFnDependencyNode    fn;
+    static MObjectHandle layerManagerHandle { MObject::kNullObj };
+    if (layerManagerHandle.isValid() && layerManagerHandle.isAlive()) {
+        MObject mobj { layerManagerHandle.object() };
+        if (!mobj.isNull()) {
+            fn.setObject(mobj);
+            return static_cast<MayaUsd::LayerManager*>(fn.userNode());
+        }
+    }
+
     MItDependencyNodes iter(MFn::kPluginDependNode);
     for (; !iter.isDone(); iter.next()) {
         MObject mobj = iter.item();
         fn.setObject(mobj);
         if (fn.typeId() == MayaUsd::LayerManager::typeId && !fn.isFromReferencedFile()) {
+            layerManagerHandle = mobj;
             return static_cast<MayaUsd::LayerManager*>(fn.userNode());
         }
     }