[rbrowser] support xRooNode and rootfit browsing

gui/browsable/inc/ROOT/Browsable/RShared.hxx

@@ -26,7 +26,7 @@ template<class T>
 class RShared : public RHolder {
    std::shared_ptr<T> fShared;   ///<! holder without IO
 protected:
-   void *GetShared() const final { return &fShared; }
+   void *GetShared() const final { return (void *) &fShared; }
    RHolder* DoCopy() const final { return new RShared<T>(fShared); }
 public:
    RShared(T *obj) { fShared.reset(obj); }

gui/browsable/src/TObjectElement.cxx

@@ -593,6 +593,8 @@ class RTObjectProvider : public RProvider {
       RegisterClass("TGeoVolume", "sap-icon://product", "libROOTGeoBrowseProvider");
       RegisterClass("TGeoNode", "sap-icon://product", "libROOTGeoBrowseProvider");
 
+      RegisterClass("RooWorkspace", "sap-icon://list", "libROOTFitWorkspaceProvider");
+
       RegisterBrowse(TFolder::Class(), [](std::unique_ptr<RHolder> &object) -> std::shared_ptr<RElement> {
          return std::make_shared<TFolderElement>(object);
       });

roofit/xroofit/CMakeLists.txt

@@ -34,3 +34,16 @@ ROOT_STANDARD_LIBRARY_PACKAGE(RooFitXRooFit
 target_include_directories(RooFitXRooFit PRIVATE inc/RooFit)
 
 ROOT_ADD_TEST_SUBDIRECTORY(test)
+
+if(webgui)
+  # provider for browsing of RooWorkspace
+
+  ROOT_LINKER_LIBRARY(ROOTFitWorkspaceProvider
+      src/xRooProvider.cxx
+    DEPENDENCIES
+      ROOTBrowsable
+      RooFitCore
+      RooFitXRooFit
+  )
+
+endif(webgui)

roofit/xroofit/src/xRooNode.cxx

@@ -110,7 +110,7 @@ auto &GETWSSNAPSHOTS(RooWorkspace *w)
 }
 auto GETACTBROWSER(TRootBrowser *b)
 {
-   return b->GetActBrowser();
+   return b ? b->GetActBrowser() : nullptr;
 }
 auto GETROOTDIR(TGFileBrowser *b)
 {

roofit/xroofit/src/xRooProvider.cxx

@@ -0,0 +1,173 @@
+/*************************************************************************
+ * Copyright (C) 1995-2021, Rene Brun and Fons Rademakers.               *
+ * All rights reserved.                                                  *
+ *                                                                       *
+ * For the licensing terms see $ROOTSYS/LICENSE.                         *
+ * For the list of contributors see $ROOTSYS/README/CREDITS.             *
+ *************************************************************************/
+
+#include <ROOT/Browsable/RElement.hxx>
+#include <ROOT/Browsable/RProvider.hxx>
+#include <ROOT/Browsable/TObjectItem.hxx>
+#include <ROOT/Browsable/RLevelIter.hxx>
+#include <ROOT/Browsable/RShared.hxx>
+
+#include <RooFit/xRooFit/xRooNode.h>
+
+#include "TVirtualPad.h"
+
+#include "RooWorkspace.h"
+
+using namespace ROOT::Browsable;
+using namespace std::string_literals;
+using namespace ROOT::Experimental::XRooFit;
+
+class xRooBrowsingElement : public RElement {
+   std::shared_ptr<xRooNode> fNode;
+public:
+   xRooBrowsingElement(std::shared_ptr<xRooNode> node)
+   {
+      fNode = node;
+   }
+
+   bool IsCapable(EActionKind action) const override
+   {
+      return (action == kActDraw6) || (action == kActBrowse);
+   }
+
+   /** Get default action */
+   EActionKind GetDefaultAction() const override
+   {
+      if (fNode->IsFolder())
+         return kActBrowse;
+      return kActDraw6;
+   }
+
+   std::string GetName() const override
+   {
+      return fNode->GetName();
+   }
+
+   std::string GetTitle() const override
+   {
+      return fNode->GetTitle();
+   }
+
+
+   bool IsFolder() const override
+   {
+      return fNode->IsFolder();
+   }
+
+   int GetNumChilds() override
+   {
+      return fNode->IsFolder() ? (int) fNode->size() : 0;
+   }
+
+   std::unique_ptr<RHolder> GetObject() override
+   {
+      return std::make_unique<RShared<xRooNode>>(fNode);
+   }
+
+   std::unique_ptr<RLevelIter> GetChildsIter() override;
+};
+
+class xRooLevelIter : public RLevelIter {
+
+   std::shared_ptr<xRooNode> fNode;
+
+   int fCounter{-1};
+
+public:
+   explicit xRooLevelIter(std::shared_ptr<xRooNode> node) { fNode = node; }
+
+   ~xRooLevelIter() override = default;
+
+   auto NumElements() const { return fNode->size(); }
+
+   bool Next() override { return ++fCounter < (int) fNode->size(); }
+
+   std::string GetItemName() const override { return (*fNode)[fCounter]->GetName(); }
+
+   bool CanItemHaveChilds() const override
+   {
+      return (*fNode)[fCounter]->IsFolder();
+   }
+
+   /** Create item for the browser */
+   std::unique_ptr<RItem> CreateItem() override
+   {
+      auto xnode = (*fNode)[fCounter];
+
+      auto item = std::make_unique<TObjectItem>(xnode->GetName(), xnode->size());
+
+      item->SetTitle(xnode->GetTitle());
+
+      item->SetClassName(xnode->get()->ClassName());
+      item->SetIcon(RProvider::GetClassIcon(xnode->get()->IsA(), xnode->IsFolder()));
+
+      return item;
+   }
+
+   /** Returns full information for current element */
+   std::shared_ptr<RElement> GetElement() override
+   {
+      auto xnode = (*fNode)[fCounter];
+      return std::make_shared<xRooBrowsingElement>(xnode);
+   }
+
+   bool Find(const std::string &name, int indx = -1) override
+   {
+      if ((indx >= 0) && (indx < (int) fNode->size()) && (name == (*fNode)[indx]->GetName())) {
+         fCounter = indx;
+         return true;
+      }
+
+      return RLevelIter::Find(name, -1);
+   }
+};
+
+
+std::unique_ptr<RLevelIter> xRooBrowsingElement::GetChildsIter()
+{
+   // here central part of hole story
+   // one need to provide list of sub-items via iterator
+
+   fNode->browse();
+
+   if (fNode->size() == 0)
+      return nullptr;
+
+   return std::make_unique<xRooLevelIter>(fNode);
+}
+
+// ==============================================================================================
+
+class xRooProvider : public RProvider {
+
+public:
+   xRooProvider()
+   {
+      RegisterBrowse(RooWorkspace::Class(), [](std::unique_ptr<RHolder> &object) -> std::shared_ptr<RElement> {
+         auto wk = object->get_shared<RooWorkspace>();
+
+         auto wkNode = std::make_shared<xRooNode>(wk);
+
+         return std::make_shared<xRooBrowsingElement>(wkNode);
+      });
+
+      RegisterDraw6(xRooNode::Class(), [this](TVirtualPad *pad, std::unique_ptr<RHolder> &obj, const std::string &opt) -> bool {
+         auto xnode = const_cast<xRooNode *>(obj->Get<xRooNode>());
+         if (!xnode)
+            return false;
+
+         pad->cd();
+         xnode->Draw(opt.c_str());
+         return true;
+      });
+
+      // example how custom icons can be provided
+      RegisterClass("RooRealVar", "sap-icon://picture");
+   }
+
+} newxRooProvider;