[DD4hep] Introduce FilteredView nextChild

DetectorDescription/DDCMS/interface/DDFilteredView.h

@@ -112,6 +112,7 @@ namespace cms {
 
     //! set the current node to the first child
     bool firstChild();
+    bool nextChild();
 
     //! set the current node to the child in path
     std::vector<std::vector<Node*>> children(const std::string& path);

DetectorDescription/DDCMS/src/DDFilteredView.cc

@@ -239,6 +239,28 @@ bool DDFilteredView::firstChild() {
   return false;
 }
 
+bool DDFilteredView::nextChild() {
+  currentSpecPar_ = nullptr;
+
+  if (it_.empty()) {
+    LogVerbatim("DDFilteredView") << "Iterator vector has zero size.";
+    return false;
+  }
+  it_.back().SetType(0);
+  Node* node = nullptr;
+  while ((node = it_.back().Next())) {
+    if (it_.back().GetLevel() <= startLevel_) {
+      return false;
+    }
+    if (accept(noNamespace(node->GetVolume()->GetName()))) {
+      node_ = node;
+      return true;
+    }
+  }
+  LogVerbatim("DDFilteredView") << "Search for first child failed.";
+  return false;
+}
+
 int DDFilteredView::nodeCopyNo(const std::string_view copyNo) const {
   int result;
   if (auto [p, ec] = std::from_chars(copyNo.data(), copyNo.data() + copyNo.size(), result); ec == std::errc()) {

DetectorDescription/DDCMS/test/BuildFile.xml

@@ -4,6 +4,11 @@
   <use name="dd4hep"/>
 </bin>
 
+<bin name="testDD4hepFilteredViewFirstChild" file="DDFilteredView.firstChild.cppunit.cc,testRunner.cpp">
+  <use name="DetectorDescription/DDCMS"/>
+  <use name="dd4hep"/>
+</bin>
+
 <bin name="testDD4hepFilteredViewLevel" file="DDFilteredView.level.cppunit.cc,testRunner.cpp">
   <use name="DetectorDescription/DDCMS"/>
   <use name="dd4hep"/>

DetectorDescription/DDCMS/test/DDFilteredView.firstChild.cppunit.cc

@@ -0,0 +1,87 @@
+#include <cppunit/extensions/HelperMacros.h>
+
+#include "DetectorDescription/DDCMS/interface/DDFilteredView.h"
+#include "DetectorDescription/DDCMS/interface/DDDetector.h"
+#include "FWCore/ParameterSet/interface/FileInPath.h"
+#include "DD4hep/Detector.h"
+
+#include <string>
+#include <memory>
+
+#include "cppunit/TestAssert.h"
+#include "cppunit/TestFixture.h"
+
+using namespace cms;
+using namespace std;
+
+class testDDFilteredViewFirstChild : public CppUnit::TestFixture {
+  CPPUNIT_TEST_SUITE(testDDFilteredViewFirstChild);
+  CPPUNIT_TEST(checkFilteredViewFirstChild);
+  CPPUNIT_TEST_SUITE_END();
+
+public:
+  void setUp() override;
+  void tearDown() override {}
+  void checkFilteredViewFirstChild();
+
+private:
+  string fileName_;
+  vector<double> refdattl_;
+  vector<string> refsattl_;
+  vector<double> refdLongFL_;
+  vector<string> refsLongFL_;
+};
+
+CPPUNIT_TEST_SUITE_REGISTRATION(testDDFilteredViewFirstChild);
+
+void testDDFilteredViewFirstChild::setUp() {
+  fileName_ = edm::FileInPath("Geometry/CMSCommonData/data/dd4hep/cmsExtendedGeometry2021.xml").fullPath();
+  refdattl_ = {0.000809653, 0.000713002, 0.000654918, 0.000602767, 0.000566295, 0.000541647, 0.000516174, 0.000502512,
+               0.000504225, 0.000506212, 0.000506275, 0.000487621, 0.000473034, 0.000454002, 0.000442383, 0.000441043,
+               0.000443609, 0.000433124, 0.000440188, 0.000435257, 0.000439224, 0.000431385, 0.00041707,  0.000415677,
+               0.000408389, 0.000400293, 0.000400989, 0.000395417, 0.00038936,  0.000383942};
+  refsattl_ = {"0.8096535E-03/cm", "0.7130018E-03/cm", "0.6549183E-03/cm", "0.6027666E-03/cm", "0.5662951E-03/cm",
+               "0.5416475E-03/cm", "0.5161745E-03/cm", "0.5025120E-03/cm", "0.5042249E-03/cm", "0.5062117E-03/cm",
+               "0.5062750E-03/cm", "0.4876212E-03/cm", "0.4730343E-03/cm", "0.4540021E-03/cm", "0.4423832E-03/cm",
+               "0.4410428E-03/cm", "0.4436095E-03/cm", "0.4331241E-03/cm", "0.4401879E-03/cm", "0.4352570E-03/cm",
+               "0.4392237E-03/cm", "0.4313847E-03/cm", "0.4170704E-03/cm", "0.4156771E-03/cm", "0.4083890E-03/cm",
+               "0.4002930E-03/cm", "0.4009888E-03/cm", "0.3954170E-03/cm", "0.3893599E-03/cm", "0.3839422E-03/cm"};
+  refdLongFL_ = {
+      227.993, 237.122, 241.701, 256.48, 266.754, 275.988, 276.982, 284.989, 286.307, 290.478, 290.5, 292, 295.5};
+  refsLongFL_ = {"227.9925651*cm",
+                 "237.1215213*cm",
+                 "241.7005445*cm",
+                 "256.47981*cm",
+                 "266.7540042*cm",
+                 "275.987715*cm",
+                 "276.9823529*cm",
+                 "284.9889299*cm",
+                 "286.3065327*cm",
+                 "290.4779412*cm",
+                 "290.5*cm",
+                 "292.0*cm",
+                 "295.5*cm"};
+}
+
+void testDDFilteredViewFirstChild::checkFilteredViewFirstChild() {
+  unique_ptr<DDDetector> det = make_unique<DDDetector>("DUMMY", fileName_);
+  DDFilteredView fview(det.get(), det->description()->worldVolume());
+  const cms::DDSpecParRegistry& mypar = det->specpars();
+  std::string attribute{"CMSCutsRegion"};
+  cms::DDSpecParRefs ref;
+  mypar.filter(ref, attribute, "MuonChamber");
+  fview.mergedSpecifics(ref);
+
+  fview.firstChild();
+  std::cout << fview.name() << " is a " << cms::dd::name(cms::DDSolidShapeMap, fview.shape()) << "\n";
+  std::cout << "Full path to it is " << fview.path() << "\n";
+  auto copyNos = fview.copyNos();
+  if (dd4hep::isA<dd4hep::Box>(fview.solid()))
+    cout << "It's a Box\n";
+
+  std::cout << fview.name() << " is a " << cms::dd::name(cms::DDSolidShapeMap, fview.shape()) << "\n";
+  do {
+    std::cout << fview.path() << "\n";
+  } while (fview.nextChild());
+  std::cout << "Current node is:\n" << fview.path() << "\n";
+}