From 2ce75be5032c36661846cf180c9abeb7312eb8f8 Mon Sep 17 00:00:00 2001
From: Markus Frank <Markus.Frank@cern.ch>
Date: Mon, 9 Oct 2023 16:28:57 +0200
Subject: [PATCH] Allow to load CAD files with relative path w/r to declaring
 xml file (Issue 1166)

---
 DDCAD/src/plugins/CADPlugins.cpp              | 31 +++++++++++++++++--
 examples/DDCAD/CMakeLists.txt                 |  2 +-
 .../compact/Check_Shape_RelativePath.xml      | 30 ++++++++++++++++++
 3 files changed, 59 insertions(+), 4 deletions(-)
 create mode 100644 examples/DDCAD/compact/Check_Shape_RelativePath.xml

diff --git a/DDCAD/src/plugins/CADPlugins.cpp b/DDCAD/src/plugins/CADPlugins.cpp
index 8a646ebe9..17f9c037a 100644
--- a/DDCAD/src/plugins/CADPlugins.cpp
+++ b/DDCAD/src/plugins/CADPlugins.cpp
@@ -20,11 +20,36 @@
 #include <DDCAD/ASSIMPWriter.h>
 
 // C/C++ include files
+#include <filesystem>
 
 using namespace std;
 using namespace dd4hep;
 using namespace dd4hep::detail;
 
+/// If the path to the CAD file does not directly exist try to resolve it:
+static string resolve_path(xml_h e, const string& file)   {
+  error_code errc;
+  std::string fname;
+  /// Use the xml utilities in the DocumentHandler to resolve the relative path
+  if ( file.length() > 7 && file.substr(0,7) == "file://" )
+    fname = file.substr(7);
+  else
+    fname = file;
+  if ( !filesystem::exists(fname, errc) )   {
+    string fn = xml::DocumentHandler::system_path(e, fname);
+    if ( fn.length() > 7 && fn.substr(0,7) == "file://" )
+      fn = fn.substr(7);
+    if ( !std::filesystem::exists(fn, errc) )   {
+      auto fp = filesystem::path(xml::DocumentHandler::system_path(e)).parent_path();
+      except("CAD_Shape","+++ CAD file: %s (= %s + %s) is not accessible [%d: %s]",
+             fn.c_str(), fp.c_str(), fname.c_str(),
+             errc.value(), errc.message().c_str());
+    }
+    return fn;
+  }
+  return fname;
+}
+
 static void* read_CAD_Volume(Detector& dsc, int argc, char** argv)   {
   string fname;
   double scale = 1.0;
@@ -61,7 +86,7 @@ DECLARE_DD4HEP_CONSTRUCTOR(DD4hep_read_CAD_volumes,read_CAD_Volume)
 static Handle<TObject> create_CAD_Shape(Detector& dsc, xml_h e)   {
   xml_elt_t elt(e);
   cad::ASSIMPReader rdr(dsc);
-  string fname = elt.attr<string>(_U(ref));
+  string fname = resolve_path(e, elt.attr<string>(_U(ref)));
   long   flags = elt.hasAttr(_U(flags)) ? elt.attr<long>(_U(flags))  : 0;
   double unit  = elt.hasAttr(_U(unit))  ? elt.attr<double>(_U(unit)) : dd4hep::cm;
 
@@ -97,7 +122,7 @@ DECLARE_XML_SHAPE(CAD_Shape__shape_constructor,create_CAD_Shape)
 
 static Handle<TObject> create_CAD_Assembly(Detector& dsc, xml_h e)   {
   xml_elt_t elt(e);
-  string fname = elt.attr<string>(_U(ref));
+  string fname = resolve_path(e, elt.attr<string>(_U(ref)));
   double unit  = elt.hasAttr(_U(unit)) ? elt.attr<double>(_U(unit)) : dd4hep::cm;
   auto volumes = cad::ASSIMPReader(dsc).readVolumes(fname, unit);
   if ( volumes.empty() )   {
@@ -159,8 +184,8 @@ DECLARE_XML_VOLUME(CAD_Assembly__volume_constructor,create_CAD_Assembly)
  */
 static Handle<TObject> create_CAD_Volume(Detector& dsc, xml_h e)   {
   xml_elt_t elt(e);
-  string fname = elt.attr<string>(_U(ref));
   double unit  = elt.attr<double>(_U(unit));
+  string fname = resolve_path(e, elt.attr<string>(_U(ref)));
   long   flags = elt.hasAttr(_U(flags)) ? elt.attr<long>(_U(flags))  : 0;
   cad::ASSIMPReader rdr(dsc);
 
diff --git a/examples/DDCAD/CMakeLists.txt b/examples/DDCAD/CMakeLists.txt
index 91f2d8a2f..0d9e38ec7 100644
--- a/examples/DDCAD/CMakeLists.txt
+++ b/examples/DDCAD/CMakeLists.txt
@@ -72,7 +72,7 @@ endforeach()
 #
 # Multi-shape tests
 # Not working: OBJ_spider
-list(APPEND DDCAD_Tests_MV COB_dwarf MS3D_jeep)
+list(APPEND DDCAD_Tests_MV COB_dwarf MS3D_jeep RelativePath)
 foreach (test ${DDCAD_Tests_MV})
   dd4hep_add_test_reg( DDCAD_Check_Shape_${test}
     COMMAND    "${CMAKE_INSTALL_PREFIX}/bin/run_test_DDCAD.sh"
diff --git a/examples/DDCAD/compact/Check_Shape_RelativePath.xml b/examples/DDCAD/compact/Check_Shape_RelativePath.xml
new file mode 100644
index 000000000..39b1627b2
--- /dev/null
+++ b/examples/DDCAD/compact/Check_Shape_RelativePath.xml
@@ -0,0 +1,30 @@
+<lccdd>
+<!-- #==========================================================================
+     #  AIDA Detector description implementation 
+     #==========================================================================
+     # Copyright (C) Organisation europeenne pour la Recherche nucleaire (CERN)
+     # All rights reserved.
+     #
+     # For the licensing terms see $DD4hepINSTALL/LICENSE.
+     # For the list of contributors see $DD4hepINSTALL/doc/CREDITS.
+     #
+     #==========================================================================
+
+     Test to verify functionality of loading CAD files with pathes relative 
+     to the declaring xml file. [See Issue 1166: Allow to give CAD files with 
+     relative paths similar to importing xml files (DDCAD) ]
+
+-->
+
+  <includes>
+    <gdmlFile ref="../../ClientTests/compact/CheckShape.xml"/>
+  </includes>
+
+  <detectors>
+    <detector id="1" name="Shape_MS3D" type="DD4hep_TestShape_Creator">
+      <check vis="Shape1_vis">
+        <shape type="CAD_MultiVolume" ref="../models/MS3D/jeep1.ms3d" unit="cm"/>
+      </check>
+    </detector>
+  </detectors>
+</lccdd>