MAYA-122926 reset auto-edit in all variants

- Add a utility function to apply a function to all variants of a prim.
- Add a utility class to automatically restore the current variant on exit.
- Use these to clear the auto-edit flag in all variants.
- Remove obsolete comments about type info not being correctly preserved and psuhEnd not being called (now it is called).

Author: pierrebai-adsk

lib/mayaUsd/utils/CMakeLists.txt

@@ -22,6 +22,7 @@ target_sources(${PROJECT_NAME}
         util.cpp
         utilFileSystem.cpp
         utilSerialization.cpp
+        variants.cpp
 )
 
 set(HEADERS
@@ -43,6 +44,7 @@ set(HEADERS
     util.h
     utilFileSystem.h
     utilSerialization.h
+    variants.h
 )
 
 set(PLUGINFO

lib/mayaUsd/utils/variants.cpp

@@ -0,0 +1,62 @@
+//
+// Copyright 2022 Autodesk
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#include "variants.h"
+
+#include <pxr/usd/usd/stage.h>
+
+/// General utility functions for variants
+namespace MAYAUSD_NS_DEF {
+
+void applyToAllVariants(
+    const PXR_NS::UsdPrim&       primWithVariants,
+    bool                         includeNonVariant,
+    const std::function<void()>& func)
+{
+    // Record if we saw at least one variant to apply the function on.
+    // Used when non-variant are included.
+    bool atLeastOneVariant = false;
+
+    // Clear the edit flag in all other variants, in all variant sets if any.
+    PXR_NS::UsdStagePtr    stage = primWithVariants.GetStage();
+    PXR_NS::UsdVariantSets variantSets = primWithVariants.GetVariantSets();
+    for (const std::string& variantSetName : variantSets.GetNames()) {
+
+        PXR_NS::UsdVariantSet variantSet = primWithVariants.GetVariantSet(variantSetName);
+
+        // Make sure to restore the current selected variant even if the face
+        // of exceptions.
+        AutoVariantRestore variantRestore(variantSet);
+
+        for (const std::string& variantName : variantSet.GetVariantNames()) {
+            if (variantSet.SetVariantSelection(variantName)) {
+                PXR_NS::UsdEditTarget target = stage->GetEditTarget();
+
+                PXR_NS::UsdEditContext switchEditContext(
+                    stage, variantSet.GetVariantEditTarget(target.GetLayer()));
+
+                func();
+                atLeastOneVariant = true;
+            }
+        }
+    }
+
+    // When not a single variant was found and the caller wants to apply
+    // the function even in the absence of vairants, call it now.
+    if (includeNonVariant && !atLeastOneVariant)
+        func();
+}
+
+} // namespace MAYAUSD_NS_DEF

lib/mayaUsd/utils/variants.h

@@ -0,0 +1,75 @@
+//
+// Copyright 2022 Autodesk
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+#ifndef MAYAUSD_UTILS_VARIANTS_H
+#define MAYAUSD_UTILS_VARIANTS_H
+
+#include <mayaUsd/base/api.h>
+
+#include <pxr/usd/usd/editContext.h>
+#include <pxr/usd/usd/prim.h>
+#include <pxr/usd/usd/variantSets.h>
+
+#include <functional>
+#include <string>
+
+/// General utility functions for variants
+namespace MAYAUSD_NS_DEF {
+
+/*! \brief Apply a function to all variants on a prim.
+
+    Optionally, if includeNonVariant is true, apply it even if the prim
+    has no variant at all, which is useful when you want to edit something
+    on all variations of a prim, even if there are no variations.
+*/
+MAYAUSD_CORE_PUBLIC
+void applyToAllVariants(
+    const PXR_NS::UsdPrim&       primWithVariants,
+    bool                         includeNonVariant,
+    const std::function<void()>& func);
+
+/*! \brief Keep track of the current variant and restore it on destruction.
+
+    The reason we don't make this an variant auto-switcher is that
+    switching variant recomposes the stage and one main user of the
+    restore is visiting all variants, which would double the number
+    of recompose if we restored the variant between each visit.
+
+    IOW, for a set with three variants A, B, C, this design permits
+    the switch Current -> A -> B -> C -> Current instead of doing
+    Current -> A -> Current -> B -> Current -> C -> Current.
+*/
+
+class AutoVariantRestore
+{
+public:
+    MAYAUSD_CORE_PUBLIC
+    AutoVariantRestore(PXR_NS::UsdVariantSet& variantSet)
+        : _variantSet(variantSet)
+        , _variant(variantSet.GetVariantSelection())
+    {
+    }
+
+    MAYAUSD_CORE_PUBLIC
+    ~AutoVariantRestore() { _variantSet.SetVariantSelection(_variant); }
+
+private:
+    PXR_NS::UsdVariantSet& _variantSet;
+    std::string            _variant;
+};
+
+} // namespace MAYAUSD_NS_DEF
+
+#endif // MAYAUSD_UTILS_VARIANTS_H

lib/usd/translators/mayaReferenceUpdater.cpp

@@ -25,6 +25,7 @@
 #include <mayaUsd/utils/editRouter.h>
 #include <mayaUsd/utils/util.h>
 #include <mayaUsd/utils/utilSerialization.h>
+#include <mayaUsd/utils/variants.h>
 #include <mayaUsdUtils/MergePrims.h>
 #include <mayaUsd_Schemas/ALMayaReference.h>
 #include <mayaUsd_Schemas/MayaReference.h>
@@ -48,14 +49,21 @@
 
 namespace {
 
+// Clear the auto-edit flag on a USD Maya Reference so that it does not
+// get edited immediately again. Clear in all variants, since each
+// variant has its own copy of the flag.
 void clearAutoEdit(const UsdPrim& prim)
 {
-    if (prim.IsValid()) {
+    UsdPrim parentPrim = prim.GetParent();
+    MAYAUSD_NS::applyToAllVariants(parentPrim, true, [prim]() {
+        // Note: the prim might not exist in all variants, so check its validity.
+        if (!prim.IsValid())
+            return;
+
         UsdAttribute mayaAutoEditAttr = prim.GetAttribute(MayaUsd_SchemasTokens->mayaAutoEdit);
-        if (mayaAutoEditAttr.IsValid()) {
+        if (mayaAutoEditAttr.IsValid())
             mayaAutoEditAttr.Set<bool>(false);
-        }
-    }
+    });
 }
 
 std::string findValue(const PXR_NS::VtDictionary& routingData, const PXR_NS::TfToken& key)
@@ -214,9 +222,6 @@ UsdMayaPrimUpdater::PushCopySpecs PxrUsdTranslators_MayaReferenceUpdater::pushCo
 
     // The Maya reference is meant as a cache, and therefore fully
     // overwritten, so we don't call MayaUsdUtils::mergePrims().
-    // As of 13-Dec-2021 pushEnd() will not be called on the
-    // MayaReferenceUpdater, because the prim updater type information
-    // is not correctly preserved.  Unload the reference here.  PPT.
     if (SdfCopySpec(srcLayer, srcSdfPath, dstLayer, dstPath)) {
         const MObject& parentNode = getMayaObject();
         UsdMayaTranslatorMayaReference::UnloadMayaReference(parentNode);
@@ -256,11 +261,6 @@ bool PxrUsdTranslators_MayaReferenceUpdater::discardEdits()
 /* virtual */
 bool PxrUsdTranslators_MayaReferenceUpdater::pushEnd()
 {
-    // As of 25-Feb-2022 the Maya transform node pulled from the Maya reference
-    // prim ends up being unlocked by the unlock traversal in
-    // PrimUpdaterManager::mergeToUsd().  However, more robust to enforce
-    // separation of concerns and perform the inverse of editAsMaya() here.
-
     // Unnecessary to unlock individual attributes, as the Maya transform node
     // is removed at pushEnd().
     MDagPath transformPath;