Use pgjdbc algorithm to convert XA xids into strings.

This commit is contained in:
Daniele Varrazzo 2010-10-10 22:54:24 +01:00
parent 17d70babb1
commit c0c116dcc4
2 changed files with 64 additions and 3 deletions

View File

@ -320,13 +320,49 @@ XidObject *xid_ensure(PyObject *oxid)
}
/* Return a base64-encoded string. */
static PyObject *
_xid_encode64(PyObject *s)
{
PyObject *base64 = NULL;
PyObject *encode = NULL;
PyObject *out = NULL;
PyObject *rv = NULL;
if (!(base64 = PyImport_ImportModule("base64"))) { goto exit; }
if (!(encode = PyObject_GetAttrString(base64, "b64encode"))) { goto exit; }
if (!(out = PyObject_CallFunctionObjArgs(encode, s, NULL))) { goto exit; }
/* we are going to use PyString_AS_STRING on this so let's ensure it. */
if (!PyString_Check(out)) {
PyErr_SetString(PyExc_TypeError,
"base64.b64encode didn't return a string");
goto exit;
}
rv = out;
out = NULL;
exit:
Py_XDECREF(out);
Py_XDECREF(encode);
Py_XDECREF(base64);
return rv;
}
/* Return the PostgreSQL transaction_id for this XA xid.
*
* PostgreSQL wants just a string, while the DBAPI supports the XA standard
* and thus a triple. We use the same conversion algorithm implemented by JDBC
* in order to allow some form of interoperation.
*
* The function must be called while holding the GIL.
* Return a buffer allocated with PyMem_Malloc. Use PyMem_Free to free it.
*
* see also: the pgjdbc implementation
* http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/jdbc/pgjdbc/org/postgresql/xa/RecoveredXid.java?rev=1.2
*/
char *
xid_get_tid(XidObject *self)
@ -334,6 +370,9 @@ xid_get_tid(XidObject *self)
char *buf = NULL;
long format_id;
Py_ssize_t bufsize = 0;
PyObject *egtrid = NULL;
PyObject *ebqual = NULL;
PyObject *tid = NULL;
format_id = PyInt_AsLong(self->format_id);
if (-1 == format_id && PyErr_Occurred()) { goto exit; }
@ -347,9 +386,15 @@ xid_get_tid(XidObject *self)
strncpy(buf, PyString_AsString(self->gtrid), bufsize);
}
else {
/* TODO: for the moment just use the string mashed up by James.
* later will implement the JDBC algorithm. */
bufsize = 1 + strlen(self->pg_xact_id);
if (!(egtrid = _xid_encode64(self->gtrid))) { goto exit; }
if (!(ebqual = _xid_encode64(self->bqual))) { goto exit; }
if (!(tid = PyString_FromFormat("%ld_%s_%s",
format_id,
PyString_AS_STRING(egtrid),
PyString_AS_STRING(ebqual)))) {
goto exit;
}
bufsize = 1 + PyString_Size(tid);
if (!(buf = (char *)PyMem_Malloc(bufsize))) {
PyErr_NoMemory();
goto exit;
@ -358,6 +403,10 @@ xid_get_tid(XidObject *self)
}
exit:
Py_XDECREF(egtrid);
Py_XDECREF(ebqual);
Py_XDECREF(tid);
return buf;
}

View File

@ -296,6 +296,18 @@ class ConnectionTwoPhaseTests(unittest.TestCase):
self.assertEqual(xid.owner, owner)
self.assertEqual(xid.database, database)
def test_xid_encoding(self):
cnn = self.connect()
xid = cnn.xid(42, "gtrid", "bqual")
cnn.tpc_begin(xid)
cnn.tpc_prepare()
cnn = self.connect()
cur = cnn.cursor()
cur.execute("select gid from pg_prepared_xacts where database = %s;",
(tests.dbname,))
self.assertEqual('42_Z3RyaWQ=_YnF1YWw=', cur.fetchone()[0])
def test_suite():
return unittest.TestLoader().loadTestsFromName(__name__)