[SofaPython3] Add a LinkPath object in both the binding and plugin.

Plugin/CMakeLists.txt

@@ -8,6 +8,7 @@ set(HEADER_FILES
 
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/DataCache.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/DataHelper.h
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/LinkPath.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/PythonFactory.h
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/Prefab.h
 )
@@ -19,6 +20,7 @@ set(SOURCE_FILES
 
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/DataCache.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/DataHelper.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/LinkPath.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/PythonFactory.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/src/SofaPython3/Prefab.cpp
 )

Plugin/src/SofaPython3/DataHelper.cpp

@@ -25,9 +25,11 @@
 #include <sofa/simulation/Node.h>
 
 #include <SofaPython3/DataHelper.h>
+#include <SofaPython3/LinkPath.h>
 #include <SofaPython3/DataCache.h>
 #include <SofaPython3/PythonFactory.h>
 
+
 using sofa::core::objectmodel::BaseLink;
 
 namespace sofapython3
@@ -62,6 +64,12 @@ std::string toSofaParsableString(const py::handle& p)
         return toSofaParsableString(o);
     }
 
+    // if the object is a link path we set it.
+    if(py::isinstance<sofapython3::LinkPath>(p))
+    {
+        return py::str(p);
+    }
+
     return py::repr(p);
 }
 
@@ -463,7 +471,7 @@ BaseData* deriveTypeFromParent(sofa::core::objectmodel::BaseContext* ctx, const
 bool isProtectedKeyword(const std::string& name)
 {
     if (name == "children" || name == "objects" || name == "parents" ||
-            name == "data" || name == "links")
+            name == "data" || name == "links" || name == "linkpath")
     {
         return true;
     }

Plugin/src/SofaPython3/LinkPath.cpp

@@ -0,0 +1,43 @@
+/******************************************************************************
+*                 SOFA, Simulation Open-Framework Architecture                *
+*                    (c) 2021 INRIA, USTL, UJF, CNRS, MGH                     *
+*                                                                             *
+* This program is free software; you can redistribute it and/or modify it     *
+* under the terms of the GNU Lesser General Public License as published by    *
+* the Free Software Foundation; either version 2.1 of the License, or (at     *
+* your option) any later version.                                             *
+*                                                                             *
+* This program is distributed in the hope that it will be useful, but WITHOUT *
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or       *
+* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License *
+* for more details.                                                           *
+*                                                                             *
+* You should have received a copy of the GNU Lesser General Public License    *
+* along with this program. If not, see <http://www.gnu.org/licenses/>.        *
+*******************************************************************************
+* Contact information: [email protected]                             *
+******************************************************************************/
+
+#include <SofaPython3/LinkPath.h>
+
+namespace sofapython3
+{
+
+LinkPath::LinkPath(sofa::core::sptr<sofa::core::objectmodel::Base> target)
+{
+    targetBase = target;
+    targetData = nullptr;
+}
+
+LinkPath::LinkPath(sofa::core::objectmodel::BaseData* target)
+{
+    targetBase = target->getOwner();
+    targetData = target;
+}
+
+bool LinkPath::isPointingToData() const
+{
+    return targetData != nullptr;
+}
+
+}/// namespace sofapython3

Plugin/src/SofaPython3/LinkPath.h

@@ -0,0 +1,46 @@
+/******************************************************************************
+*                 SOFA, Simulation Open-Framework Architecture                *
+*                    (c) 2021 INRIA, USTL, UJF, CNRS, MGH                     *
+*                                                                             *
+* This program is free software; you can redistribute it and/or modify it     *
+* under the terms of the GNU Lesser General Public License as published by    *
+* the Free Software Foundation; either version 2.1 of the License, or (at     *
+* your option) any later version.                                             *
+*                                                                             *
+* This program is distributed in the hope that it will be useful, but WITHOUT *
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or       *
+* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License *
+* for more details.                                                           *
+*                                                                             *
+* You should have received a copy of the GNU Lesser General Public License    *
+* along with this program. If not, see <http://www.gnu.org/licenses/>.        *
+*******************************************************************************
+* Contact information: [email protected]                             *
+******************************************************************************/
+
+#pragma once
+
+#include <sofa/core/objectmodel/Base.h>
+#include <sofa/core/objectmodel/BaseData.h>
+
+namespace sofapython3
+{
+
+/// A placeholder class storing a link to a data or a base
+///
+/// LinkPath can be used to indicate that a link is needed to be made in place of a string
+/// like "@/usr/myobj.position" or "@/usr/myobj"
+///
+class LinkPath
+{
+public:
+    sofa::core::sptr<sofa::core::objectmodel::Base> targetBase;
+    sofa::core::objectmodel::BaseData* targetData;
+
+    LinkPath(sofa::core::sptr<sofa::core::objectmodel::Base>);
+    LinkPath(sofa::core::objectmodel::BaseData*);
+
+    bool isPointingToData() const;
+};
+
+} /// sofapython3

Plugin/src/SofaPython3/PythonFactory.cpp

@@ -52,6 +52,7 @@ using sofa::core::objectmodel::ScriptEvent;
 using sofa::core::objectmodel::Event;
 
 #include <SofaPython3/PythonEnvironment.h>
+#include <SofaPython3/LinkPath.h>
 
 #include <sofa/core/topology/Topology.h>
 
@@ -293,6 +294,12 @@ void copyFromListOf<std::string>(BaseData& d, const AbstractTypeInfo& nfo, const
 
 void PythonFactory::fromPython(BaseData* d, const py::object& o)
 {
+    if(py::isinstance<sofapython3::LinkPath>(o))
+    {
+        d->setParent(py::cast<LinkPath&>(o).targetData);
+        return;
+    }
+
     const AbstractTypeInfo& nfo{ *(d->getValueTypeInfo()) };
 
     // Is this data field a container ?

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_Base.cpp

@@ -33,6 +33,7 @@ using sofa::helper::WriteOnlyAccessor;
 
 #include <SofaPython3/PythonFactory.h>
 
+#include <SofaPython3/Sofa/Core/Binding_LinkPath.h>
 #include <SofaPython3/Sofa/Core/Binding_Base.h>
 #include <SofaPython3/Sofa/Core/Binding_Base_doc.h>
 #include <SofaPython3/Sofa/Core/Binding_DataDict.h>
@@ -90,6 +91,10 @@ py::object BindingBase::GetAttr(Base* self, const std::string& s, bool doThrowEx
     if( s == "__data__")
         return py::cast( DataDict(self) );
 
+    /// Returns the linkpath to the self object.
+    if(s == "linkpath")
+        return py::cast(sofapython3::LinkPath(self));
+
     if(doThrowException)
         throw py::attribute_error("Missing attribute: "+s);
 
@@ -101,18 +106,34 @@ bool BindingBase::SetData(BaseData* d, py::object value)
     if(d==nullptr)
         return false;
 
-    const AbstractTypeInfo& nfo{ *(d->getValueTypeInfo()) };
-
     PythonFactory::fromPython(d, value);
     return true;
 }
 
+bool BindingBase::SetLink(BaseLink* link, py::object value)
+{
+    if(link==nullptr)
+        return false;
+
+    if(py::isinstance<py::str>(value))
+        return link->read(py::cast<py::str>(value));
+
+    if(py::isinstance<LinkPath>(value))
+    {
+        auto& target = py::cast<LinkPath&>(value);
+        if(target.isPointingToData())
+            throw std::runtime_error("Passing a link to a data field instead of an object.");
+        link->setLinkedBase(target.targetBase.get());
+    }
+    return true;
+}
+
 
 void BindingBase::SetAttr(py::object self, const std::string& s, py::object value)
 {
     Base* self_d = py::cast<Base*>(self);
-    BaseData* d = self_d->findData(s);
 
+    BaseData* d = self_d->findData(s);
     if(d!=nullptr)
     {
         SetData(d, value);
@@ -122,6 +143,7 @@ void BindingBase::SetAttr(py::object self, const std::string& s, py::object valu
     BaseLink* l = self_d->findLink(s);
     if(l!=nullptr)
     {
+        SetLink(l, value);
         return;
     }
 
@@ -132,24 +154,16 @@ void BindingBase::SetAttr(py::object self, const std::string& s, py::object valu
 void BindingBase::SetAttr(Base& self, const std::string& s, py::object value)
 {
     BaseData* d = self.findData(s);
-
     if(d!=nullptr)
     {
-        const AbstractTypeInfo& nfo{ *(d->getValueTypeInfo()) };
-
-        /// We go for the container path.
-        if(nfo.Container())
-        {
-            PythonFactory::fromPython(d,value);
-            return;
-        }
         PythonFactory::fromPython(d, value);
         return;
     }
 
     BaseLink* l = self.findLink(s);
     if(l!=nullptr)
     {
+        SetLink(l, value);
         return;
     }
 

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_Base.h

@@ -48,6 +48,7 @@ class BindingBase
     /// Set the data field value from the array.
     static void SetDataFromArray(sofa::core::objectmodel::BaseData* data, const pybind11::array& value);
     static bool SetData(sofa::core::objectmodel::BaseData* data, pybind11::object value);
+    static bool SetLink(sofa::core::objectmodel::BaseLink* link, pybind11::object value);
     static pybind11::object setDataValues(sofa::core::objectmodel::Base& self, pybind11::kwargs kwargs);
 
     static pybind11::list getDataFields(sofa::core::objectmodel::Base& self);

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_BaseData.cpp

@@ -29,6 +29,7 @@
 #include <SofaPython3/Sofa/Core/Binding_Base.h>
 #include <SofaPython3/Sofa/Core/Binding_BaseData.h>
 #include <SofaPython3/Sofa/Core/Binding_BaseData_doc.h>
+#include <SofaPython3/Sofa/Core/Binding_LinkPath.h>
 #include <SofaPython3/Sofa/Core/Data/Binding_DataContainer.h>
 #include <SofaPython3/DataHelper.h>
 #include <SofaPython3/PythonFactory.h>
@@ -139,7 +140,7 @@ py::object __getattr__(py::object self, const std::string& s)
         return PythonFactory::valueToPython_ro(py::cast<BaseData*>(self));
 
     if(s == "linkpath")
-        return py::cast((py::cast<BaseData*>(self))->getLinkPath());
+        return py::cast(sofapython3::LinkPath(py::cast<BaseData*>(self)));
 
     /// BaseData does not support dynamic attributes, if you think this is an important feature
     /// please request for its integration.
@@ -151,11 +152,18 @@ void setParent(BaseData* self, BaseData* parent)
     self->setParent(parent);
 }
 
-void setParentFromLinkPath(BaseData* self, const std::string& parent)
+void setParentFromLinkPathStr(BaseData* self, const std::string& parent)
 {
     self->setParent(parent);
 }
 
+void setParentFromLinkPath(BaseData* self, const LinkPath& parent)
+{
+    if(!parent.isPointingToData())
+        throw std::runtime_error("The provided linkpath is not containing a linkable data");
+    self->setParent(parent.targetData);
+}
+
 bool hasParent(BaseData *self)
 {
     return (self->getParent() != nullptr);
@@ -205,6 +213,7 @@ void moduleAddBaseData(py::module& m)
     data.def("isPersistent", &BaseData::isPersistent, sofapython3::doc::baseData::isPersistent);
     data.def("setPersistent", &BaseData::setPersistent, sofapython3::doc::baseData::setPersistent);
     data.def("setParent", setParent, sofapython3::doc::baseData::setParent);
+    data.def("setParent", setParentFromLinkPathStr, sofapython3::doc::baseData::setParent);
     data.def("setParent", setParentFromLinkPath, sofapython3::doc::baseData::setParent);
     data.def("hasParent", hasParent, sofapython3::doc::baseData::hasParent);
     data.def("read", &BaseData::read, sofapython3::doc::baseData::read);

bindings/Sofa/src/SofaPython3/Sofa/Core/Binding_LinkPath.cpp

@@ -0,0 +1,84 @@
+/******************************************************************************
+*                 SOFA, Simulation Open-Framework Architecture                *
+*                    (c) 2021 INRIA, USTL, UJF, CNRS, MGH                     *
+*                                                                             *
+* This program is free software; you can redistribute it and/or modify it     *
+* under the terms of the GNU Lesser General Public License as published by    *
+* the Free Software Foundation; either version 2.1 of the License, or (at     *
+* your option) any later version.                                             *
+*                                                                             *
+* This program is distributed in the hope that it will be useful, but WITHOUT *
+* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or       *
+* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License *
+* for more details.                                                           *
+*                                                                             *
+* You should have received a copy of the GNU Lesser General Public License    *
+* along with this program. If not, see <http://www.gnu.org/licenses/>.        *
+*******************************************************************************
+* Contact information: [email protected]                             *
+******************************************************************************/
+
+#include <sofa/core/objectmodel/BaseLink.h>
+using sofa::core::objectmodel::BaseLink;
+
+#include <sofa/core/objectmodel/BaseObject.h>
+using  sofa::core::objectmodel::BaseObject;
+
+#include <SofaPython3/Sofa/Core/Binding_LinkPath.h>
+#include <SofaPython3/Sofa/Core/Binding_LinkPath_doc.h>
+
+/// Makes an alias for the pybind11 namespace to increase readability.
+namespace py { using namespace pybind11; }
+
+// To bring in the `_a` literal
+using namespace pybind11::literals;
+
+namespace sofapython3
+{
+
+LinkPath::LinkPath(sofa::core::sptr<sofa::core::objectmodel::Base> target)
+{
+    targetBase = target;
+    targetData = nullptr;
+}
+
+LinkPath::LinkPath(sofa::core::objectmodel::BaseData* target)
+{
+    // If the data is attached to
+    if(target->getOwner())
+    {
+        targetBase = target->getOwner();
+    }
+    targetData = target;
+}
+
+bool LinkPath::isPointingToData() const
+{
+    return targetData != nullptr;
+}
+
+std::string __str__(const LinkPath& entry)
+{
+    std::ostringstream s;
+    if(entry.targetData != nullptr)
+        return entry.targetData->getLinkPath();
+    else if(entry.targetBase.get() != nullptr)
+        return "@" + entry.targetBase->getPathName();
+    throw std::runtime_error("Empty LinkPath");
+}
+
+std::string __repr__(const LinkPath& entry)
+{
+    std::ostringstream s;
+    s << "LinkPath(\"" << __str__(entry) << "\")";
+    return s.str();
+}
+
+void moduleAddLinkPath(py::module& m)
+{
+    py::class_<LinkPath> link(m, "LinkPath", sofapython3::doc::linkpath::linkpath);
+    link.def("__str__", &__str__);
+    link.def("__repr__", &__repr__);
+}
+
+}/// namespace sofapython3