[hdsi] Avoid unnecessary data access in HdsiPinnedCurveExpandingScene…

…Index

Ensure HdsiPinnedCurveExpandingSceneIndex does not pull
on the basisCurves schema when asked for unrelated
keys.

(Internal change: 2328958)

pxr/imaging/hdsi/pinnedCurveExpandingSceneIndex.cpp

@@ -754,63 +754,65 @@ class _PrimDataSource : public HdContainerDataSource
     Get(const TfToken &name) override
     {
         HdDataSourceBaseHandle result = _input->Get(name);
-        if (result) {
-            HdBasisCurvesSchema bcs =
-                HdBasisCurvesSchema::GetFromParent(_input);
-
-            if (!bcs) {
-                return result;
-            }
-
-            HdBasisCurvesTopologySchema ts = bcs.GetTopology();
-            if (!ts) {
-                return result;
-            }
+        if (!result) {
+            return HdDataSourceBaseHandle();
+        }
+        if (name != HdBasisCurvesSchemaTokens->basisCurves &&
+            name != HdPrimvarsSchemaTokens->primvars) {
+            return result;
+        }
+        HdBasisCurvesSchema bcs = HdBasisCurvesSchema::GetFromParent(_input);
+        if (!bcs) {
+            return result;
+        }
+        HdBasisCurvesTopologySchema ts = bcs.GetTopology();
+        if (!ts) {
+            return result;
+        }
 
-            // TODO: Avoid sampling sampled sources here!
-            const TfToken wrap =
-                _SafeGetTypedValue<TfToken>(ts.GetWrap());
-            const TfToken basis =
-                _SafeGetTypedValue<TfToken>(ts.GetBasis());
-
-            if (wrap == HdTokens->pinned &&
-                (basis == HdTokens->bspline ||
-                 basis == HdTokens->catmullRom ||
-                 basis == HdTokens->centripetalCatmullRom)) {
-
-                // Add 2 additional end points for bspline and
-                // 1 for catmullRom|centripetalCatmullRom.
-                const size_t numExtraEnds =
-                    (basis == HdTokens->bspline)? 2 : 1;
-
-                // Need to cache the per-curve vertex counts since the
-                // expansion is per-curve.
-                const VtIntArray curveVertexCounts =
-                    _SafeGetTypedValue<VtIntArray>(
-                        ts.GetCurveVertexCounts());
-
-                if (name == HdBasisCurvesSchemaTokens->basisCurves) {
-                    if (HdContainerDataSourceHandle bcc =
-                            HdContainerDataSource::Cast(result)) {
-                        return _BasisCurvesDataSource::New(
-                            bcc, curveVertexCounts, numExtraEnds);
-                    }
+        // TODO: Avoid sampling sampled sources here!
+        const TfToken wrap =
+            _SafeGetTypedValue<TfToken>(ts.GetWrap());
+        const TfToken basis =
+            _SafeGetTypedValue<TfToken>(ts.GetBasis());
+
+        if (wrap == HdTokens->pinned &&
+            (basis == HdTokens->bspline ||
+             basis == HdTokens->catmullRom ||
+             basis == HdTokens->centripetalCatmullRom)) {
+
+            // Add 2 additional end points for bspline and
+            // 1 for catmullRom|centripetalCatmullRom.
+            const size_t numExtraEnds =
+                (basis == HdTokens->bspline)? 2 : 1;
+
+            // Need to cache the per-curve vertex counts since the
+            // expansion is per-curve.
+            const VtIntArray curveVertexCounts =
+                _SafeGetTypedValue<VtIntArray>(
+                    ts.GetCurveVertexCounts());
+
+            if (name == HdBasisCurvesSchemaTokens->basisCurves) {
+                if (HdContainerDataSourceHandle bcc =
+                        HdContainerDataSource::Cast(result)) {
+                    return _BasisCurvesDataSource::New(
+                        bcc, curveVertexCounts, numExtraEnds);
                 }
+            }
 
-                if (name == HdPrimvarsSchemaTokens->primvars) {
-                    // If we have authored curve indices, we can avoid expanding
-                    // vertex primvars by expanding the curve indices instead.
-                    // Note that varying primvars would still need to be 
-                    // expanded due to the additional curve segments.
-                    VtIntArray curveIndices =
-                        _SafeGetTypedValue<VtIntArray>(ts.GetCurveIndices());
-
-                    if (HdContainerDataSourceHandle pc =
-                            HdContainerDataSource::Cast(result)) {
-                        return _PrimvarsDataSource::New(
-                            pc, curveVertexCounts, numExtraEnds,
-                            !curveIndices.empty());
-                    }
+            if (name == HdPrimvarsSchemaTokens->primvars) {
+                // If we have authored curve indices, we can avoid expanding
+                // vertex primvars by expanding the curve indices instead.
+                // Note that varying primvars would still need to be 
+                // expanded due to the additional curve segments.
+                VtIntArray curveIndices =
+                    _SafeGetTypedValue<VtIntArray>(ts.GetCurveIndices());
+
+                if (HdContainerDataSourceHandle pc =
+                        HdContainerDataSource::Cast(result)) {
+                    return _PrimvarsDataSource::New(
+                        pc, curveVertexCounts, numExtraEnds,
+                        !curveIndices.empty());
                 }
             }
         }