Function encoder_encode_dict_key

simplejson/_speedups.c:3107–3153

Stringify and encode a dict key to its JSON representation, using the * key_memo cache for string keys. Returns a new reference to the encoded * key string on success, Py_None (borrowed, no new reference) for * skipkeys, or NULL on error. */

 * key string on success, Py_None (borrowed, no new reference) for
 * skipkeys, or NULL on error. */
static PyObject *
encoder_encode_dict_key(PyEncoderObject *s, PyObject *key)
{
    PyObject *kstr;
    PyObject *encoded;

    kstr = encoder_stringify_key(s, key);
    if (kstr == NULL)
        return NULL;
    if (kstr == Py_None) {
        Py_DECREF(kstr);
        return Py_None;  /* skipkeys */
    }

    /* For string keys (PyUnicode on Py3, PyString on Py2),
     * encoder_stringify_key returns Py_INCREF(key) — i.e. kstr IS key.
     * For non-string keys it returns a freshly created string, so
     * kstr != key.  Use this identity test to decide whether the
     * key_memo cache applies: caching under a non-string original key
     * would be write-only (the lookup uses kstr, not key). */
    if (kstr == key) {
        int cached = json_PyDict_GetItemRef(s->key_memo, kstr, &encoded);
        if (cached < 0) {
            Py_DECREF(kstr);
            return NULL;
        }
        if (cached == 0) {
            encoded = encoder_encode_string(s, kstr);
            if (encoded == NULL) {
                Py_DECREF(kstr);
                return NULL;
            }
            if (PyDict_SetItem(s->key_memo, key, encoded)) {
                Py_DECREF(kstr);
                Py_DECREF(encoded);
                return NULL;
            }
        }
        Py_DECREF(kstr);
    } else {
        encoded = encoder_encode_string(s, kstr);
        Py_DECREF(kstr);
        if (encoded == NULL)
            return NULL;
    }
    return encoded;  /* new reference */
}

/* Write '\n' followed by indent_level copies of s->indent directly to
 * the accumulator, without materializing the combined string as an