gh-132775: Add _PyMarshal_GetXIData() (gh-133108)

Note that the bulk of this change is tests.

1 files changed, 43 insertions, 0 deletions

diff --git a/Python/crossinterp.c b/Python/crossinterp.c
index 662c9c72b15..753d784a503 100644
--- a/Python/crossinterp.c
+++ b/Python/crossinterp.c
@@ -2,6 +2,7 @@
 /* API for managing interactions between isolated interpreters */
 
 #include "Python.h"
+#include "marshal.h"              // PyMarshal_WriteObjectToString()
 #include "pycore_ceval.h"         // _Py_simple_func
 #include "pycore_crossinterp.h"   // _PyXIData_t
 #include "pycore_initconfig.h"    // _PyStatus_OK()
@@ -286,6 +287,48 @@ _PyObject_GetXIData(PyThreadState *tstate,
 }
 
 
+/* marshal wrapper */
+
+PyObject *
+_PyMarshal_ReadObjectFromXIData(_PyXIData_t *xidata)
+{
+    PyThreadState *tstate = _PyThreadState_GET();
+    _PyBytes_data_t *shared = (_PyBytes_data_t *)xidata->data;
+    PyObject *obj = PyMarshal_ReadObjectFromString(shared->bytes, shared->len);
+    if (obj == NULL) {
+        PyObject *cause = _PyErr_GetRaisedException(tstate);
+        assert(cause != NULL);
+        _set_xid_lookup_failure(
+                    tstate, NULL, "object could not be unmarshalled", cause);
+        Py_DECREF(cause);
+        return NULL;
+    }
+    return obj;
+}
+
+int
+_PyMarshal_GetXIData(PyThreadState *tstate, PyObject *obj, _PyXIData_t *xidata)
+{
+    PyObject *bytes = PyMarshal_WriteObjectToString(obj, Py_MARSHAL_VERSION);
+    if (bytes == NULL) {
+        PyObject *cause = _PyErr_GetRaisedException(tstate);
+        assert(cause != NULL);
+        _set_xid_lookup_failure(
+                    tstate, NULL, "object could not be marshalled", cause);
+        Py_DECREF(cause);
+        return -1;
+    }
+    size_t size = sizeof(_PyBytes_data_t);
+    _PyBytes_data_t *shared = _PyBytes_GetXIDataWrapped(
+            tstate, bytes, size, _PyMarshal_ReadObjectFromXIData, xidata);
+    Py_DECREF(bytes);
+    if (shared == NULL) {
+        return -1;
+    }
+    return 0;
+}
+
+
 /* using cross-interpreter data */
 
 PyObject *