Added tpc_recover method.

psycopg/connection.h

@@ -135,6 +135,7 @@ HIDDEN int  conn_poll(connectionObject *self);
 HIDDEN int  conn_tpc_begin(connectionObject *self, XidObject *xid);
 HIDDEN int  conn_tpc_command(connectionObject *self,
                              const char *cmd, XidObject *xid);
+HIDDEN PyObject *conn_tpc_recover(connectionObject *self);
 
 /* exception-raising macros */
 #define EXC_IF_CONN_CLOSED(self) if ((self)->closed > 0) { \

psycopg/connection_int.c

@@ -957,3 +957,36 @@ conn_tpc_command(connectionObject *self, const char *cmd, XidObject *xid)
     return rv;
 }
 
+/* conn_tpc_recover -- return a list of pending TPC Xid */
+
+PyObject *
+conn_tpc_recover(connectionObject *self)
+{
+    int status;
+    PyObject *xids = NULL;
+    PyObject *rv = NULL;
+    PyObject *tmp;
+
+    /* store the status to restore it. */
+    status = self->status;
+
+    if (!(xids = xid_recover((PyObject *)self))) { goto exit; }
+
+    if (status == CONN_STATUS_READY && self->status == CONN_STATUS_BEGIN) {
+        /* recover began a transaction: let's abort it. */
+        if (!(tmp = PyObject_CallMethod((PyObject *)self, "rollback", NULL))) {
+            goto exit;
+        }
+        Py_DECREF(tmp);
+    }
+
+    /* all fine */
+    rv = xids;
+    xids = NULL;
+
+exit:
+    Py_XDECREF(xids);
+
+    return rv;
+
+}

psycopg/connection_type.c

@@ -381,6 +381,22 @@ psyco_conn_tpc_rollback(connectionObject *self, PyObject *args)
                                   conn_rollback, "ROLLBACK PREPARED");
 }
 
+#define psyco_conn_tpc_recover_doc \
+"tpc_recover() -- returns a list of pending transaction IDs."
+
+static PyObject *
+psyco_conn_tpc_recover(connectionObject *self, PyObject *args)
+{
+    EXC_IF_CONN_CLOSED(self);
+    EXC_IF_CONN_ASYNC(self, tpc_recover);
+    EXC_IF_TPC_PREPARED(self, tpc_recover);
+
+    if (!PyArg_ParseTuple(args, "")) { return NULL; }
+
+    return conn_tpc_recover(self);
+}
+
+
 #ifdef PSYCOPG_EXTENSIONS
 
 /* set_isolation_level method - switch connection isolation level */
@@ -720,6 +736,8 @@ static struct PyMethodDef connectionObject_methods[] = {
      METH_VARARGS, psyco_conn_tpc_commit_doc},
     {"tpc_rollback", (PyCFunction)psyco_conn_tpc_rollback,
      METH_VARARGS, psyco_conn_tpc_rollback_doc},
+    {"tpc_recover", (PyCFunction)psyco_conn_tpc_recover,
+     METH_VARARGS, psyco_conn_tpc_recover_doc},
 #ifdef PSYCOPG_EXTENSIONS
     {"set_isolation_level", (PyCFunction)psyco_conn_set_isolation_level,
      METH_VARARGS, psyco_conn_set_isolation_level_doc},

psycopg/xid.h

@@ -31,6 +31,9 @@
 
 #include "psycopg/config.h"
 
+/* value for the format_id when the xid doesn't follow the XA standard. */
+#define XID_UNPARSED (-2)
+
 extern HIDDEN PyTypeObject XidType;
 
 typedef struct {
@@ -51,6 +54,8 @@ typedef struct {
 } XidObject;
 
 HIDDEN XidObject *xid_ensure(PyObject *oxid);
+HIDDEN XidObject *xid_from_string(PyObject *s);
 HIDDEN char *xid_get_tid(XidObject *self);
+HIDDEN PyObject *xid_recover(PyObject *conn);
 
 #endif /* PSYCOPG_XID_H */

psycopg/xid_type.c

@@ -331,21 +331,170 @@ XidObject *xid_ensure(PyObject *oxid)
 char *
 xid_get_tid(XidObject *self)
 {
-    /* TODO: for the moment just use the string mashed up by James.
-     * later will implement the JDBC algorithm. */
-    char *buf;
+    char *buf = NULL;
+    long format_id;
     Py_ssize_t bufsize = 0;
 
-    if (self->pg_xact_id) {
-        bufsize = 1 + strlen(self->pg_xact_id);
-    }
+    format_id = PyInt_AsLong(self->format_id);
+    if (-1 == format_id && PyErr_Occurred()) { goto exit; }
 
-    buf = (char *)PyMem_Malloc(bufsize);
-    if (buf) {
+    if (XID_UNPARSED == format_id) {
+        bufsize = 1 + PyString_Size(self->gtrid);
+        if (!(buf = (char *)PyMem_Malloc(bufsize))) {
+            PyErr_NoMemory();
+            goto exit;
+        }
+        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 (!(buf = (char *)PyMem_Malloc(bufsize))) {
+            PyErr_NoMemory();
+            goto exit;
+        }
         strncpy(buf, self->pg_xact_id, bufsize);
     }
 
+exit:
     return buf;
 }
 
+/* Build a Xid from a string representation.
+ *
+ * If the xid is in the format generated by Psycopg, unpack the tuple into
+ * the struct members. Otherwise generate an "unparsed" xid.
+ */
+XidObject *
+xid_from_string(PyObject *str) {
+    /* TODO: currently always generates an unparsed xid. */
+    XidObject *xid = NULL;
+    XidObject *rv = NULL;
+    PyObject *format_id = NULL;
+    PyObject *tmp;
 
+    /* fake args to work around the checks performed by the xid init */
+    if (!(xid = (XidObject *)PyObject_CallFunction((PyObject *)&XidType,
+            "iss", 0, "tmp", "tmp"))) {
+        goto exit;
+    }
+
+    /* set xid.gtrid */
+    tmp = xid->gtrid;
+    Py_INCREF(str);
+    xid->gtrid = str;
+    Py_DECREF(tmp);
+
+    /* set xid.format_id */
+    if (!(format_id = PyInt_FromLong(XID_UNPARSED))) { goto exit; }
+    tmp = xid->format_id;
+    xid->format_id = format_id;
+    format_id = NULL;
+    Py_DECREF(tmp);
+
+    /* set xid.bqual */
+    tmp = xid->bqual;
+    Py_INCREF(Py_None);
+    xid->bqual = Py_None;
+    Py_DECREF(tmp);
+
+    /* return the finished object */
+    rv = xid;
+    xid = NULL;
+
+exit:
+    Py_XDECREF(format_id);
+    Py_XDECREF(xid);
+
+    return rv;
+}
+
+/* conn_tpc_recover -- return a list of pending TPC Xid */
+
+PyObject *
+xid_recover(PyObject *conn)
+{
+    PyObject *rv = NULL;
+    PyObject *curs = NULL;
+    PyObject *xids = NULL;
+    XidObject *xid = NULL;
+    PyObject *recs = NULL;
+    PyObject *rec = NULL;
+    PyObject *item = NULL;
+    PyObject *tmp;
+    Py_ssize_t len, i;
+
+    /* curs = conn.cursor() */
+    if (!(curs = PyObject_CallMethod(conn, "cursor", NULL))) { goto exit; }
+
+    /* curs.execute(...) */
+    if (!(tmp = PyObject_CallMethod(curs, "execute", "s",
+        "SELECT gid, prepared, owner, database FROM pg_prepared_xacts;")))
+    {
+        goto exit;
+    }
+    Py_DECREF(tmp);
+
+    /* recs = curs.fetchall() */
+    if (!(recs = PyObject_CallMethod(curs, "fetchall", NULL))) { goto exit; }
+
+    /* curs.close() */
+    if (!(tmp = PyObject_CallMethod(curs, "close", NULL))) { goto exit; }
+    Py_DECREF(tmp);
+
+    /* Build the list with return values. */
+    if (0 > (len = PySequence_Size(recs))) { goto exit; }
+    if (!(xids = PyList_New(len))) { goto exit; }
+
+    /* populate the xids list */
+    for (i = 0; i < len; ++i) {
+        if (!(rec = PySequence_GetItem(recs, i))) { goto exit; }
+
+        /* Get the xid with the XA triple set */
+        if (!(item = PySequence_GetItem(rec, 0))) { goto exit; }
+        if (!(xid = xid_from_string(item))) { goto exit; }
+        Py_DECREF(item); item = NULL;
+
+        /* set xid.prepared */
+        if (!(item = PySequence_GetItem(rec, 1))) { goto exit; }
+        tmp = xid->prepared;
+        xid->prepared = item;
+        Py_DECREF(tmp);
+        item = NULL;
+
+        /* set xid.owner */
+        if (!(item = PySequence_GetItem(rec, 2))) { goto exit; }
+        tmp = xid->owner;
+        xid->owner = item;
+        Py_DECREF(tmp);
+        item = NULL;
+
+        /* set xid.database */
+        if (!(item = PySequence_GetItem(rec, 3))) { goto exit; }
+        tmp = xid->database;
+        xid->database = item;
+        Py_DECREF(tmp);
+        item = NULL;
+
+        /* xid finished: add it to the returned list */
+        PyList_SET_ITEM(xids, i, (PyObject *)xid);
+        xid = NULL;  /* ref stolen */
+
+        Py_DECREF(rec); rec = NULL;
+    }
+
+    /* set the return value. */
+    rv = xids;
+    xids = NULL;
+
+exit:
+    Py_XDECREF(xids);
+    Py_XDECREF(xid);
+    Py_XDECREF(curs);
+    Py_XDECREF(recs);
+    Py_XDECREF(rec);
+    Py_XDECREF(item);
+
+    return rv;
+}

tests/test_connection.py

@@ -1,6 +1,8 @@
 #!/usr/bin/env python
 
 import unittest
+from operator import attrgetter
+
 import psycopg2
 import psycopg2.extensions
 import tests
@@ -64,6 +66,73 @@ class ConnectionTests(unittest.TestCase):
         conn = self.connect()
         self.assert_(conn.encoding in psycopg2.extensions.encodings)
 
+
+class ConnectionTwoPhaseTests(unittest.TestCase):
+    def setUp(self):
+        self.clear_test_xacts()
+
+    def tearDown(self):
+        self.clear_test_xacts()
+
+    def clear_test_xacts(self):
+        """Rollback all the prepared transaction in the testing db."""
+        cnn = self.connect()
+        cnn.set_isolation_level(0)
+        cur = cnn.cursor()
+        cur.execute(
+            "select gid from pg_prepared_xacts where database = %s",
+            (tests.dbname,))
+        gids = [ r[0] for r in cur ]
+        for gid in gids:
+            cur.execute("rollback prepared %s;", (gid,))
+        cnn.close()
+
+    def connect(self):
+        return psycopg2.connect(tests.dsn)
+
+    def test_status_after_recover(self):
+        cnn = self.connect()
+        self.assertEqual(psycopg2.extensions.STATUS_READY, cnn.status)
+        xns = cnn.tpc_recover()
+        self.assertEqual(psycopg2.extensions.STATUS_READY, cnn.status)
+
+        cur = cnn.cursor()
+        cur.execute("select 1")
+        self.assertEqual(psycopg2.extensions.STATUS_BEGIN, cnn.status)
+        xns = cnn.tpc_recover()
+        self.assertEqual(psycopg2.extensions.STATUS_BEGIN, cnn.status)
+
+    def test_recovered_xids(self):
+        # insert a few test xns
+        cnn = self.connect()
+        cnn.set_isolation_level(0)
+        cur = cnn.cursor()
+        cur.execute("begin; prepare transaction '1-foo';")
+        cur.execute("begin; prepare transaction '2-bar';")
+
+        # read the values to return
+        cur.execute("""
+            select gid, prepared, owner, database
+            from pg_prepared_xacts
+            where database = %s;""",
+            (tests.dbname,))
+        okvals = cur.fetchall()
+        okvals.sort()
+
+        cnn = self.connect()
+        xids = cnn.tpc_recover()
+        xids = [ xid for xid in xids if xid.database == tests.dbname ]
+        xids.sort(key=attrgetter('gtrid'))
+
+        # check the values returned
+        self.assertEqual(len(okvals), len(xids))
+        for (xid, (gid, prepared, owner, database)) in zip (xids, okvals):
+            self.assertEqual(xid.gtrid, gid)
+            self.assertEqual(xid.prepared, prepared)
+            self.assertEqual(xid.owner, owner)
+            self.assertEqual(xid.database, database)
+
+
 def test_suite():
     return unittest.TestLoader().loadTestsFromName(__name__)