fix(cornerstone-dicom-rt): adding caching usage to cornerstone-dicom-rt SOP Class Handler (#5387)

extensions/cornerstone-dicom-rt/src/getSopClassHandlerModule.ts

@@ -4,7 +4,11 @@ import i18n from '@ohif/i18n';
 import { SOPClassHandlerId } from './id';
 import loadRTStruct from './loadRTStruct';
 
-const sopClassUids = ['1.2.840.10008.5.1.4.1.1.481.3'];
+const { sopClassDictionary } = utils;
+
+const sopClassUids = [sopClassDictionary.RTStructureSetStorage];
+
+const cachedRTStructsSEG = new Set<string>();
 
 const loadPromises = {};
 
@@ -113,39 +117,45 @@ function _load(
 ) {
   const { SOPInstanceUID } = rtDisplaySet;
   const { segmentationService } = servicesManager.services;
+
   if (
     (rtDisplaySet.loading || rtDisplaySet.isLoaded) &&
     loadPromises[SOPInstanceUID] &&
-    _segmentationExistsInCache(rtDisplaySet, segmentationService)
+    cachedRTStructsSEG.has(rtDisplaySet.displaySetInstanceUID)
   ) {
     return loadPromises[SOPInstanceUID];
   }
 
   rtDisplaySet.loading = true;
 
+  const { unsubscribe } = segmentationService.subscribe(
+    segmentationService.EVENTS.SEGMENTATION_LOADING_COMPLETE,
+    (evt: { rtDisplaySet: { displaySetInstanceUID: string } }) => {
+      if (evt.rtDisplaySet?.displaySetInstanceUID === rtDisplaySet.displaySetInstanceUID) {
+        cachedRTStructsSEG.add(rtDisplaySet.displaySetInstanceUID);
+        unsubscribe();
+      }
+    }
+  );
+
   // We don't want to fire multiple loads, so we'll wait for the first to finish
   // and also return the same promise to any other callers.
-  loadPromises[SOPInstanceUID] = new Promise(async (resolve, reject) => {
-    if (!rtDisplaySet.structureSet) {
-      const structureSet = await loadRTStruct(extensionManager, rtDisplaySet, headers);
+  loadPromises[SOPInstanceUID] = new Promise<void>(async (resolve, reject) => {
+    try {
+      if (!rtDisplaySet.structureSet) {
+        const structureSet = await loadRTStruct(extensionManager, rtDisplaySet, headers);
+        rtDisplaySet.structureSet = structureSet;
+      }
 
-      rtDisplaySet.structureSet = structureSet;
-    }
+      if (createSegmentation) {
+        await segmentationService.createSegmentationForRTDisplaySet(rtDisplaySet);
+      }
 
-    if (createSegmentation) {
-      segmentationService
-        .createSegmentationForRTDisplaySet(rtDisplaySet)
-        .then(() => {
-          rtDisplaySet.loading = false;
-          resolve();
-        })
-        .catch(error => {
-          rtDisplaySet.loading = false;
-          reject(error);
-        });
-    } else {
-      rtDisplaySet.loading = false;
       resolve();
+    } catch (error) {
+      reject(error);
+    } finally {
+      rtDisplaySet.loading = false;
     }
   });
 
@@ -187,11 +197,6 @@ function _deriveReferencedSeriesSequenceFromFrameOfReferenceSequence(
   return ReferencedSeriesSequence;
 }
 
-function _segmentationExistsInCache() {
-  // Todo: fix this
-  return false;
-}
-
 function getSopClassHandlerModule(params: OhifTypes.Extensions.ExtensionParams) {
   const { servicesManager, extensionManager } = params;