MAYA-106722 Maya check callback to see if there are any unsaved edits

plugin/adsk/plugin/CMakeLists.txt

@@ -29,6 +29,7 @@ target_sources(${TARGET_NAME}
         importTranslator.cpp
         exportTranslator.cpp
         ProxyShape.cpp
+        sceneResetCheck.cpp
 )
 
 # -----------------------------------------------------------------------------

plugin/adsk/plugin/base/api.h

@@ -42,3 +42,7 @@
 #define MAYAUSD_PLUGIN_LOCAL
 #endif
 #endif
+
+// Convenience symbol versioning include: because api.h is widely
+// included, this reduces the need to explicitly include mayaUsd.h.
+#include <mayaUsd/mayaUsd.h>

plugin/adsk/plugin/plugin.cpp

@@ -20,6 +20,7 @@
 #include "base/api.h"
 #include "exportTranslator.h"
 #include "importTranslator.h"
+#include "sceneResetCheck.h"
 
 #include <mayaUsd/base/api.h>
 #include <mayaUsd/commands/editTargetCommand.h>
@@ -201,6 +202,8 @@ MStatus initializePlugin(MObject obj)
 
     UsdMayaSceneResetNotice::InstallListener();
 
+    MayaUsd::SceneResetCheck::registerSceneResetCheckCallback();
+
     return status;
 }
 
@@ -259,5 +262,7 @@ MStatus uninitializePlugin(MObject obj)
 
     UsdMayaSceneResetNotice::RemoveListener();
 
+    MayaUsd::SceneResetCheck::deregisterSceneResetCheckCallback();
+
     return status;
 }

plugin/adsk/plugin/sceneResetCheck.cpp

@@ -0,0 +1,115 @@
+//
+// Copyright 2020 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 "sceneResetCheck.h"
+
+#include "ProxyShape.h"
+
+#include <pxr/pxr.h>
+#include <pxr/usd/usd/common.h>
+#include <pxr/usd/usd/stage.h>
+
+#include <maya/MFnDependencyNode.h>
+#include <maya/MGlobal.h>
+#include <maya/MItDependencyNodes.h>
+#include <maya/MMessage.h>
+#include <maya/MSceneMessage.h>
+
+PXR_NAMESPACE_USING_DIRECTIVE
+
+namespace {
+MCallbackId _beforeNewCheckCallbackId = 0;
+MCallbackId _beforeOpenCheckCallbackId = 0;
+
+const char* ignoreDirtyLayersConfirmScript = R"(
+global proc string MayaUsdIgnoreDirtyLayersConfirm()
+{
+    return `confirmDialog -title "Discard USD Edits" 
+        -message "Are you sure you want to exit this session?\n\nAll edits on your USD layer(s) will be discarded."
+        -button "Yes" -button "No" -defaultButton "No" -icon "warning"
+        -cancelButton "No" -dismissString "No"`;
+
+}
+MayaUsdIgnoreDirtyLayersConfirm();
+)";
+
+static void _OnMayaNewOrOpenSceneCheckCallback(bool* retCode, void*)
+{
+    *retCode = true;
+
+    bool atLeastOneDirty = false;
+
+    MFnDependencyNode  fn;
+    MItDependencyNodes iter(MFn::kPluginDependNode);
+
+    for (; !iter.isDone() && !atLeastOneDirty; iter.next()) {
+        MObject mobj = iter.item();
+        fn.setObject(mobj);
+        if (MayaUsd::ProxyShape::typeId == fn.typeId()) {
+            MayaUsdProxyShapeBase* pShape = static_cast<MayaUsdProxyShapeBase*>(fn.userNode());
+            UsdStageRefPtr         stage = pShape ? pShape->getUsdStage() : nullptr;
+            if (!stage) {
+                continue;
+            }
+
+            SdfLayerHandleVector allLayers = stage->GetLayerStack(true);
+            for (auto layer : allLayers) {
+                if (layer->IsDirty()) {
+                    atLeastOneDirty = true;
+                    break;
+                }
+            }
+        }
+    }
+
+    if (atLeastOneDirty) {
+        MString allowExit = MGlobal::executeCommandStringResult(ignoreDirtyLayersConfirmScript);
+        if (MString("No") == allowExit) {
+            *retCode = false;
+        }
+    }
+}
+
+} // namespace
+
+namespace MAYAUSD_NS_DEF {
+
+void SceneResetCheck::registerSceneResetCheckCallback()
+{
+    if (_beforeNewCheckCallbackId == 0) {
+        _beforeNewCheckCallbackId = MSceneMessage::addCheckCallback(
+            MSceneMessage::kBeforeNewCheck, _OnMayaNewOrOpenSceneCheckCallback);
+    }
+
+    if (_beforeOpenCheckCallbackId == 0) {
+        _beforeOpenCheckCallbackId = MSceneMessage::addCheckCallback(
+            MSceneMessage::kBeforeOpenCheck, _OnMayaNewOrOpenSceneCheckCallback);
+    }
+}
+
+void SceneResetCheck::deregisterSceneResetCheckCallback()
+{
+    if (_beforeNewCheckCallbackId != 0) {
+        MMessage::removeCallback(_beforeNewCheckCallbackId);
+        _beforeNewCheckCallbackId = 0;
+    }
+
+    if (_beforeOpenCheckCallbackId != 0) {
+        MMessage::removeCallback(_beforeOpenCheckCallbackId);
+        _beforeOpenCheckCallbackId = 0;
+    }
+}
+
+} // namespace MAYAUSD_NS_DEF

plugin/adsk/plugin/sceneResetCheck.h

@@ -0,0 +1,35 @@
+//
+// Copyright 2020 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 ADSK_MAYA_SCENE_RESET_CHECK_H
+#define ADSK_MAYA_SCENE_RESET_CHECK_H
+
+#include "base/api.h"
+
+namespace MAYAUSD_NS_DEF {
+
+class SceneResetCheck
+{
+public:
+    MAYAUSD_PLUGIN_PUBLIC
+    static void registerSceneResetCheckCallback();
+
+    MAYAUSD_PLUGIN_PUBLIC
+    static void deregisterSceneResetCheckCallback();
+};
+
+} // namespace MAYAUSD_NS_DEF
+
+#endif