reduce C code overhead for C++ std::string -> PyObject conversion helpers by...

reduce C code overhead for C++ std::string -> PyObject conversion helpers by implementing them directly in C++ and not Cython

Cython/Compiler/PyrexTypes.py

@@ -3075,7 +3075,12 @@ class CppClassType(CType):
     def create_to_py_utility_code(self, env):
         if self.to_py_function is not None:
             return True
-        if self.cname in builtin_cpp_conversions or self.cname in cpp_string_conversions:
+        elif self.cname in cpp_string_conversions:
+            env.use_utility_code(UtilityCode.load_cached("CppStringToPy", "CppSupport.cpp"))
+            # "PyObject" prefix gets specialised by explicit type casts in CoerceToPyTypeNode
+            self.to_py_function = '__Pyx_PyObject_FromStlString'
+            return True
+        elif self.cname in builtin_cpp_conversions:
             X = "XYZABC"
             tags = []
             declarations = ["cdef extern from *:"]
@@ -3089,14 +3094,8 @@ class CppClassType(CType):
                 declarations.append(
                     "    cdef object %s_to_py '%s' (%s)" % (
                          X[ix], T.to_py_function, X[ix]))
-            if self.cname in cpp_string_conversions:
-                cls = 'string'
-                prefix = 'PyObject_'  # gets specialised by explicit type casts in CoerceToPyTypeNode
-                tags = self.cname.replace(':', '_'),
-            else:
-                cls = self.cname[5:]
-                prefix = ''
-            cname = "__pyx_convert_%s%s_to_py_%s" % (prefix, cls, "____".join(tags))
+            cls = self.cname[5:]
+            cname = "__pyx_convert_%s_to_py_%s" % (cls, "____".join(tags))
             context = {
                 'template_type_declarations': '\n'.join(declarations),
                 'cname': cname,

Cython/Utility/CppConvert.pyx

@@ -16,36 +16,6 @@ cdef string {{cname}}(object o) except *:
     return string(data, length)
 
 
-#################### string.to_py ####################
-
-#cimport cython
-#from libcpp.string cimport string
-cdef extern from *:
-    cdef cppclass string "{{type}}":
-        char* data()
-        size_t size()
-    cdef object __Pyx_PyObject_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyBytes_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyByteArray_FromStringAndSize(char*, size_t)
-    cdef object __Pyx_PyUnicode_FromStringAndSize(char*, size_t)
-
-@cname("{{cname}}")
-cdef inline object {{cname}}(const string& s):
-    return __Pyx_PyObject_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyUnicode")}}")
-cdef inline object {{cname.replace("PyObject", "PyUnicode")}}(const string& s):
-    return __Pyx_PyUnicode_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyBytes")}}")
-cdef inline object {{cname.replace("PyObject", "PyBytes")}}(const string& s):
-    return __Pyx_PyBytes_FromStringAndSize(s.data(), s.size())
-
-@cname("{{cname.replace("PyObject", "PyByteArray")}}")
-cdef inline object {{cname.replace("PyObject", "PyByteArray")}}(const string& s):
-    return __Pyx_PyByteArray_FromStringAndSize(s.data(), s.size())
-
-
 #################### vector.from_py ####################
 
 {{template_type_declarations}}

Cython/Utility/CppSupport.cpp

@@ -44,3 +44,29 @@ static void __Pyx_CppExn2PyErr() {
   }
 }
 #endif
+
+
+/////////////// CppStringToPy.proto ///////////////
+
+static CYTHON_INLINE PyObject *__Pyx_PyObject_FromStlString(std::string const &s);
+static CYTHON_INLINE PyObject *__Pyx_PyUnicode_FromStlString(std::string const &s);
+static CYTHON_INLINE PyObject *__Pyx_PyBytes_FromStlString(std::string const &s);
+static CYTHON_INLINE PyObject *__Pyx_PyByteArray_FromStlString(std::string const &s);
+
+/////////////// CppStringToPy ///////////////
+
+static CYTHON_INLINE PyObject *__Pyx_PyObject_FromStlString(std::string const &s) {
+    return __Pyx_PyObject_FromStringAndSize(s.data(), s.size());
+}
+
+static CYTHON_INLINE PyObject *__Pyx_PyUnicode_FromStlString(std::string const &s) {
+    return __Pyx_PyUnicode_FromStringAndSize(s.data(), s.size());
+}
+
+static CYTHON_INLINE PyObject *__Pyx_PyBytes_FromStlString(std::string const &s) {
+    return __Pyx_PyBytes_FromStringAndSize(s.data(), s.size());
+}
+
+static CYTHON_INLINE PyObject *__Pyx_PyByteArray_FromStlString(std::string const &s) {
+    return __Pyx_PyByteArray_FromStringAndSize(s.data(), s.size());
+}