Implement C API function 'PyUnicode_AsUnicodeEscapeString'.

Author: fangerer

graalpython/com.oracle.graal.python.cext/src/unicodeobject.c

@@ -387,3 +387,8 @@ int PyUnicode_Compare(PyObject *left, PyObject *right) {
 int _PyUnicode_EqualToASCIIString( PyObject *left, const char *right) {
 	return UPCALL_CEXT_I(_jls_PyUnicode_Compare, native_to_java(left), polyglot_from_string(right, SRC_CS)) == 0;
 }
+
+UPCALL_ID(PyUnicode_AsUnicodeEscapeString);
+PyObject * PyUnicode_AsUnicodeEscapeString(PyObject *unicode) {
+	return UPCALL_CEXT_O(_jls_PyUnicode_AsUnicodeEscapeString, native_to_java(unicode));
+}

graalpython/com.oracle.graal.python.test/src/tests/cpyext/test_unicode.py

@@ -70,6 +70,11 @@ def _reference_findchar(args):
         return string.rfind(char, start, end)
 
 
+def _reference_unicode_escape(args):
+    import _codecs
+    return _codecs.unicode_escape_encode(args[0])[0]
+
+
 class CustomString(str):
     pass
 
@@ -464,3 +469,15 @@ def compile_module(self, name):
         arguments=["PyObject* str", "PyObject* seq"],
         cmpfunc=unhandled_error_compare
     )
+    
+    test_PyUnicode_AsUnicodeEscapeString = CPyExtFunction(
+        _reference_unicode_escape,
+        lambda: (
+            ("abcd", ),
+            ("öüä", ),
+        ),
+        resultspec="O",
+        argspec='O',
+        arguments=["PyObject* str"],
+        cmpfunc=unhandled_error_compare
+    )

graalpython/lib-graalpython/python_cext.py

@@ -661,6 +661,15 @@ def PyUnicode_Compare(left, right):
         return -1
     else:
         return 1
+    
+_codecs_module = None
+
+@may_raise
+def PyUnicode_AsUnicodeEscapeString(string):
+    global _codecs_module
+    if not _codecs_module:
+        import _codecs as _codecs_module 
+    return _codecs_module.unicode_escape_encode(string)[0]
 
 
 ##################### CAPSULE