MAYA-123013 obey file-format choice in layer editor

lib/mayaUsd/nodes/layerManager.cpp

@@ -697,7 +697,7 @@ BatchSaveResult LayerDatabase::saveUsdToUsdFiles()
                 SdfLayerHandleVector allLayers = stage->GetLayerStack(false);
                 for (auto layer : allLayers) {
                     if (layer->PermissionToSave()) {
-                        layer->Save();
+                        MayaUsd::utils::saveLayerWithFormat(layer);
                     }
                 }
             }
@@ -719,9 +719,8 @@ void LayerDatabase::convertAnonymousLayers(MayaUsdProxyShapeBase* pShape, UsdSta
 
     if (root->IsAnonymous()) {
         PXR_NS::SdfFileFormat::FileFormatArguments args;
-        args["format"] = MayaUsd::utils::usdFormatArgOption();
         std::string newFileName = MayaUsd::utils::generateUniqueFileName(proxyName);
-        root->Export(newFileName, "", args);
+        MayaUsd::utils::saveLayerWithFormat(root, newFileName);
 
         MayaUsd::utils::setNewProxyPath(pShape->name(), UsdMayaUtil::convert(newFileName));
     }

lib/mayaUsd/utils/utilSerialization.cpp

@@ -184,6 +184,55 @@ void setNewProxyPath(const MString& proxyNodeName, const MString& newValue)
         /*undo*/ false);
 }
 
+static bool isCompatibleWithSave(
+    SdfLayerRefPtr     layer,
+    const std::string& filePath,
+    const std::string& formatArg)
+{
+    if (!layer)
+        return false;
+
+    // Save cannot specify the filename, so the file name must match to use save.
+    if (layer->GetRealPath() != filePath)
+        return false;
+
+    const TfToken underlyingFormat = UsdUsdFileFormat::GetUnderlyingFormatForLayer(*layer);
+    if (underlyingFormat.size()) {
+        return underlyingFormat == formatArg;
+    } else {
+        const SdfFileFormat::FileFormatArguments currentFormatArgs
+            = layer->GetFileFormatArguments();
+
+        // If we cannot find the format argument then we cannot validate that the file format match
+        // so we err to the side of safety and claim they don't match.
+        const auto keyAndValue = currentFormatArgs.find("format");
+        if (keyAndValue == currentFormatArgs.end())
+            return false;
+
+        return keyAndValue->second == formatArg;
+    }
+}
+
+bool saveLayerWithFormat(
+    SdfLayerRefPtr     layer,
+    const std::string& requestedFilePath,
+    const std::string& requestedFormatArg)
+{
+    const std::string& filePath
+        = requestedFilePath.empty() ? layer->GetRealPath() : requestedFilePath;
+
+    const std::string& formatArg
+        = requestedFormatArg.empty() ? usdFormatArgOption() : requestedFormatArg;
+
+    if (isCompatibleWithSave(layer, filePath, formatArg)) {
+        return layer->Save();
+    } else {
+        PXR_NS::SdfFileFormat::FileFormatArguments args;
+        args["format"] = formatArg;
+        return layer->Export(filePath, "", args);
+    }
+}
+
 SdfLayerRefPtr saveAnonymousLayer(
     SdfLayerRefPtr     anonLayer,
     LayerParent        parent,
@@ -204,14 +253,7 @@ SdfLayerRefPtr saveAnonymousLayer(
         return nullptr;
     }
 
-    PXR_NS::SdfFileFormat::FileFormatArguments args;
-    if (!formatArg.empty()) {
-        args["format"] = formatArg;
-    } else {
-        args["format"] = usdFormatArgOption();
-    }
-
-    anonLayer->Export(path, "", args);
+    saveLayerWithFormat(anonLayer, path, formatArg);
 
     SdfLayerRefPtr newLayer = SdfLayer::FindOrOpen(path);
     if (newLayer) {

lib/mayaUsd/utils/utilSerialization.h

@@ -82,6 +82,17 @@ struct stageLayersToSave
     std::vector<SdfLayerRefPtr>                         _dirtyFileBackedLayers;
 };
 
+/*! \brief Save an layer to disk to the given file path and using the given format.
+    If the file path is empty then use the current file path of the layer.
+    If the format is empty then use the current user-selected USD format option
+    as defined by the usdFormatArgOption() function. (See above.)
+ */
+MAYAUSD_CORE_PUBLIC
+bool saveLayerWithFormat(
+    SdfLayerRefPtr     layer,
+    const std::string& requestedFilePath = "",
+    const std::string& requestedFormatArg = "");
+
 /*! \brief Save an anonymous layer to disk and update the sublayer path array
     in the parent layer.
  */

lib/usd/translators/mayaReferenceUpdater.cpp

@@ -24,6 +24,7 @@
 #include <mayaUsd/undo/OpUndoItems.h>
 #include <mayaUsd/utils/editRouter.h>
 #include <mayaUsd/utils/util.h>
+#include <mayaUsd/utils/utilSerialization.h>
 #include <mayaUsdUtils/MergePrims.h>
 #include <mayaUsd_Schemas/ALMayaReference.h>
 #include <mayaUsd_Schemas/MayaReference.h>

lib/usd/ui/layerEditor/layerTreeItem.cpp

@@ -351,7 +351,7 @@ void LayerTreeItem::saveEditsNoPrompt()
         if (!isSessionLayer())
             saveAnonymousLayer();
     } else {
-        layer()->Save();
+        MayaUsd::utils::saveLayerWithFormat(layer());
     }
 }
 

lib/usd/ui/layerEditor/pathChecker.cpp

@@ -19,6 +19,8 @@
 #include "stringResources.h"
 #include "warningDialogs.h"
 
+#include <mayaUsd/utils/utilSerialization.h>
+
 #include <pxr/usd/ar/resolver.h>
 #include <pxr/usd/sdf/fileFormat.h>
 #include <pxr/usd/sdf/layerUtils.h>
@@ -181,10 +183,7 @@ bool saveSubLayer(
     }
 
     if (!fileError) {
-        PXR_NS::SdfFileFormat::FileFormatArguments formatArgs;
-        formatArgs["format"] = in_formatTag;
-
-        if (!in_layer->Export(in_absolutePath, "", formatArgs)) {
+        if (!MayaUsd::utils::saveLayerWithFormat(in_layer, in_absolutePath, in_formatTag)) {
             fileError = true;
         } else {
             // parent item is null if we're saving the root later

plugin/al/lib/AL_USDMaya/AL/usdmaya/cmds/LayerCommands.cpp

@@ -22,6 +22,8 @@
 #include "AL/usdmaya/nodes/ProxyShape.h"
 #include "AL/usdmaya/nodes/Transform.h"
 
+#include <mayaUsd/utils/utilSerialization.h>
+
 #include <pxr/usd/sdf/listOp.h>
 #include <pxr/usd/usd/stage.h>