Do not throw error when open an already opened document

src/App/Application.cpp

@@ -776,9 +776,8 @@ Document* Application::openDocumentPrivate(const char * FileName,
 
         if(!isMainDoc)
             return 0;
-        std::stringstream str;
-        str << "The project '" << FileName << "' is already open!";
-        throw Base::FileSystemError(str.str().c_str());
+
+        return it->second;
     }
 
     std::string name;

src/Gui/Application.cpp

@@ -518,18 +518,34 @@ void Application::open(const char* FileName, const char* Module)
 
     if (Module != 0) {
         try {
-            // issue module loading
-            Command::doCommand(Command::App, "import %s", Module);
+            if(File.hasExtension("FCStd")) {
+                bool handled = false;
+                std::string filepath = File.filePath();
+                for(auto &v : d->documents) {
+                    auto doc = v.second->getDocument();
+                    std::string fi = Base::FileInfo(doc->FileName.getValue()).filePath();
+                    if(filepath == fi) {
+                        handled = true;
+                        Command::doCommand(Command::App, "FreeCADGui.reload('%s')", doc->getName());
+                        break;
+                    }
+                }
+                if(!handled)
+                    Command::doCommand(Command::App, "FreeCAD.openDocument('%s')", FileName);
+            } else {
+                // issue module loading
+                Command::doCommand(Command::App, "import %s", Module);
 
-            // load the file with the module
-            Command::doCommand(Command::App, "%s.open(u\"%s\")", Module, unicodepath.c_str());
+                // load the file with the module
+                Command::doCommand(Command::App, "%s.open(u\"%s\")", Module, unicodepath.c_str());
 
-            // ViewFit
-            if (!File.hasExtension("FCStd") && sendHasMsgToActiveView("ViewFit")) {
-                ParameterGrp::handle hGrp = App::GetApplication().GetParameterGroupByPath
-                    ("User parameter:BaseApp/Preferences/View");
-                if (hGrp->GetBool("AutoFitToView", true))
-                    Command::doCommand(Command::Gui, "Gui.SendMsgToActiveView(\"ViewFit\")");
+                // ViewFit
+                if (sendHasMsgToActiveView("ViewFit")) {
+                    ParameterGrp::handle hGrp = App::GetApplication().GetParameterGroupByPath
+                        ("User parameter:BaseApp/Preferences/View");
+                    if (hGrp->GetBool("AutoFitToView", true))
+                        Command::doCommand(Command::Gui, "Gui.SendMsgToActiveView(\"ViewFit\")");
+                }
             }
 
             // the original file name is required
@@ -2266,6 +2282,17 @@ App::Document *Application::reopen(App::Document *doc) {
                     || d->testStatus(App::Document::PartialRestore) )
                 docs.push_back(d->FileName.getValue());
         }
+
+        if(docs.empty()) {
+            Document *gdoc = getDocument(doc);
+            if(gdoc) {
+                setActiveDocument(gdoc);
+                if(!gdoc->setActiveView())
+                    gdoc->setActiveView(0,View3DInventor::getClassTypeId());
+            }
+            return doc;
+        }
+
         for(auto &file : docs)
             App::GetApplication().openDocument(file.c_str(),false);
     }

src/Gui/Application.h

@@ -264,7 +264,8 @@ public:
     static PyObject* sOpen                     (PyObject *self,PyObject *args); // open Python scripts
     static PyObject* sInsert                   (PyObject *self,PyObject *args); // open Python scripts
     static PyObject* sExport                   (PyObject *self,PyObject *args);
-    static PyObject* sReload                   (PyObject *self,PyObject *args);
+    static PyObject* sReload                   (PyObject *self,PyObject *args); // reload FCStd file
+    static PyObject* sLoadFile                 (PyObject *self,PyObject *args); // open all types of files
 
     static PyObject* sCoinRemoveAllChildren    (PyObject *self,PyObject *args);
 

src/Gui/ApplicationPy.cpp

@@ -218,6 +218,13 @@ PyMethodDef Application::Methods[] = {
    "reload(name) -> doc\n\n"
    "Reload a partial opened document"},
 
+  {"loadFile",       (PyCFunction) Application::sLoadFile, METH_VARARGS,
+   "loadFile(string=filename,[string=module]) -> None\n\n"
+   "Loads an arbitrary file by delegating to the given Python module:\n"
+   "* If no module is given it will be determined by the file extension.\n"
+   "* If more than one module can load a file the first one one will be taken.\n"
+   "* If no module exists to load the file an exception will be raised."},
+
   {"coinRemoveAllChildren",     (PyCFunction) Application::sCoinRemoveAllChildren, METH_VARARGS,
    "Remove all children from a group node"},
 
@@ -1470,6 +1477,37 @@ PyObject* Application::sReload(PyObject * /*self*/, PyObject *args)
     Py_Return;
 }
 
+PyObject* Application::sLoadFile(PyObject * /*self*/, PyObject *args)
+{
+    char *path, *mod="";
+    if (!PyArg_ParseTuple(args, "s|s", &path, &mod))     // convert args: Python->C
+        return 0;                             // NULL triggers exception
+    PY_TRY {
+        Base::FileInfo fi(path);
+        if (!fi.isFile() || !fi.exists()) {
+            PyErr_Format(PyExc_IOError, "File %s doesn't exist.", path);
+            return 0;
+        }
+
+        std::string module = mod;
+        if (module.empty()) {
+            std::string ext = fi.extension();
+            std::vector<std::string> modules = App::GetApplication().getImportModules(ext.c_str());
+            if (modules.empty()) {
+                PyErr_Format(PyExc_IOError, "Filetype %s is not supported.", ext.c_str());
+                return 0;
+            }
+            else {
+                module = modules.front();
+            }
+        }
+
+        Application::Instance->open(path,mod);
+
+        Py_Return;
+    } PY_CATCH
+}
+
 PyObject* Application::sAddDocObserver(PyObject * /*self*/, PyObject *args)
 {
     PyObject* o;

src/Mod/Start/StartPage/LoadMRU.py

@@ -20,10 +20,10 @@
 #*                                                                         *
 #***************************************************************************
 
-import FreeCAD,sys
+import FreeCADGui,sys
 # MRU will be given before this script is run
 rf=FreeCAD.ParamGet("User parameter:BaseApp/Preferences/RecentFiles")
-FreeCAD.loadFile(rf.GetString("MRU"+str(MRU)))
+FreeCADGui.loadFile(rf.GetString("MRU"+str(MRU)))
 
 from StartPage import StartPage
 StartPage.postStart()