support dynamic cast from all parents/virtual base

cython/TODO.md

@@ -1,6 +1,5 @@
 
 TODO:
-☐ Casting from parent and grandparents 
 ☐ Allow overloading methods. The current solution is annoying!!!
 ☐ forward declaration?
 ☐ Global functions
@@ -12,6 +11,7 @@ TODO:
 ☐ CMake install script
 
 Completed/Cancelled:
+✔ Casting from parent and grandparents 
 ✔ Allow overloading constructors. The current solution is annoying!!! @done (16-11-16 17:00)
 ✔ Support "print obj" @done (16-11-16 17:00)
 ✔ methods for FastVector: at, [], ...  @done (16-11-16 17:00)

wrap/Class.cpp

@@ -770,8 +770,8 @@ void Class::pyxInitParentObj(FileWriter& pyxFile, const std::string& pyObj,
       pyxFile.oss << pyObj << "." << parentClass->pyxCythonObj() << " = "
                   << "<" << parentClass->pyxSharedCythonClass() << ">("
                   << cySharedObj << ")\n";
-      // Find the parent class with name "parentClass" and point its cython obj to the same pointer
+      // Find the parent class with name "parentClass" and point its cython obj
-      // TODO: This search is not efficient. :-(
+      // to the same pointer
       auto parent_it = find_if(allClasses.begin(), allClasses.end(),
                                [this](const Class& cls) {
                                    return cls.cythonClass() ==
@@ -785,6 +785,42 @@ void Class::pyxInitParentObj(FileWriter& pyxFile, const std::string& pyObj,
   }
 }
 
+/* ************************************************************************* */
+/*
+  @staticmethod
+  def dynamic_cast(noiseModel_Base base):
+          cdef noiseModel_Gaussian ret = noiseModel_Gaussian()
+          ret.gtnoiseModel_Gaussian_ = <shared_ptr[gtsam.noiseModel_Gaussian]>dynamic_pointer_cast[gtsam.noiseModel_Gaussian, gtsam.noiseModel_Base](base.gtnoiseModel_Base_)
+          ret.gtnoiseModel_Base_ = <shared_ptr[gtsam.noiseModel_Base]>(ret.gtnoiseModel_Gaussian_)
+          return ret
+ */
+void Class::pyxDynamicCast(FileWriter& pyxFile, const Class& curLevel,
+                           const std::vector<Class>& allClasses) const {
+  std::string me = this->pythonClass(), sharedMe = this->pyxSharedCythonClass();
+  if (curLevel.parentClass) {
+    std::string parent = curLevel.parentClass->pythonClass(),
+                parentObj = curLevel.parentClass->pyxCythonObj(),
+                parentCythonClass = curLevel.parentClass->pyxCythonClass();
+    pyxFile.oss << "def dynamic_cast_" << me << "_" << parent << "(" << parent
+                << " parent):\n";
+    pyxFile.oss << "\treturn " << me << ".cyCreateFromShared(<" << sharedMe
+                << ">dynamic_pointer_cast[" << pyxCythonClass() << ","
+                << parentCythonClass << "](parent." << parentObj
+                << "))\n";
+    // Move up higher to one level: Find the parent class with name "parentClass"
+    auto parent_it = find_if(allClasses.begin(), allClasses.end(),
+                             [&curLevel](const Class& cls) {
+                                 return cls.cythonClass() ==
+                                        curLevel.parentClass->cythonClass();
+                             });
+    if (parent_it == allClasses.end()) {
+        cerr << "Can't find parent class: " << parentClass->cythonClass();
+      throw std::runtime_error("Parent class not found!");
+    }
+    pyxDynamicCast(pyxFile, *parent_it, allClasses);
+  }
+}
+
 /* ************************************************************************* */
 void Class::emit_cython_pyx(FileWriter& pyxFile, const std::vector<Class>& allClasses) const {
   pyxFile.oss << "cdef class " << pythonClass();
@@ -853,6 +889,9 @@ void Class::emit_cython_pyx(FileWriter& pyxFile, const std::vector<Class>& allCl
 
   for(const Method& m: methods_ | boost::adaptors::map_values)
     m.emit_cython_pyx(pyxFile, *this);
+
+  pyxDynamicCast(pyxFile, *this, allClasses);
+
   pyxFile.oss << "\n\n"; 
 }
 

wrap/Class.h

@@ -160,6 +160,8 @@ public:
   void pyxInitParentObj(FileWriter& pyxFile, const std::string& pyObj,
                         const std::string& cySharedObj,
                         const std::vector<Class>& allClasses) const;
+  void pyxDynamicCast(FileWriter& pyxFile, const Class& curLevel,
+                           const std::vector<Class>& allClasses) const;
 
   friend std::ostream& operator<<(std::ostream& os, const Class& cls) {
     os << "class " << cls.name() << "{\n";

wrap/Module.cpp

@@ -338,7 +338,8 @@ void Module::emit_cython_pxd(FileWriter& pxdFile) const {
                  "\t\tshared_ptr()\n"
                  "\t\tshared_ptr(T*)\n"
                  "\t\tT* get()\n"
-                 "\t\tT& operator*()\n\n";
+                 "\t\tT& operator*()\n\n"
+                 "\tcdef shared_ptr[T] dynamic_pointer_cast[T,U](const shared_ptr[U]& r)\n";
 
   for(const TypedefPair& types: typedefs)
     types.emit_cython_pxd(pxdFile);
@@ -366,13 +367,14 @@ void Module::emit_cython_pxd(FileWriter& pxdFile) const {
   pxdFile.emit(true);
 }
 
-/* ************************************************************************* */ 
+/* ************************************************************************* */
 void Module::emit_cython_pyx(FileWriter& pyxFile) const {
   // headers...
   string pxdHeader = name + "_wrapper";
   pyxFile.oss << "cimport numpy as np\n"
                  "cimport " << pxdHeader << " as " << name << "\n"
-                 "from "<< pxdHeader << " cimport shared_ptr\n";
+                 "from "<< pxdHeader << " cimport shared_ptr\n"
+                 "from "<< pxdHeader << " cimport dynamic_pointer_cast\n";
   // import all typedefs, e.g. from gtsam cimport Key, so we don't need to say gtsam.Key
   for(const Qualified& q: Qualified::BasicTypedefs) {
     pyxFile.oss << "from " << pxdHeader << " cimport " << q.cythonClass() << "\n";