NOTIFYs fix and poll status changes

POLL_OK has been changed from 3 to 0 to let the user specify a short loop
just as "if not curs.poll()" instead of having to check for write and read
separately. For an example of this, see examples/notify.py.

ChangeLog

@@ -1,3 +1,9 @@
+2010-04-05  Federico Di Gregorio  <fog@initd.org>
+
+	* Fixed problem with asynchronous NOTIFYs.
+
+	* Integrated async pacthes from Jan's git tree.
+
 2010-03-13  Federico Di Gregorio  <fog@initd.org>
 
 	* Release 2.0.14.

examples/notify.py

@@ -39,5 +39,5 @@ while 1:
     if select.select([curs],[],[],5)==([],[],[]):
         print "Timeout"
     else:
-        if curs.isready():
+        if not curs.poll():
             print "Got NOTIFY: %s" % str(curs.connection.notifies.pop()) 

lib/extensions.py

@@ -76,10 +76,10 @@ STATUS_ASYNC    = 4
 # This is a usefull mnemonic to check if the connection is in a transaction
 STATUS_IN_TRANSACTION = STATUS_BEGIN
 
-"""psycopg async connection polling values"""
+"""psycopg asynchronous connection polling values"""
+POLL_OK    = 0
 POLL_READ  = 1
 POLL_WRITE = 2
-POLL_OK    = 3
 
 """Backend transaction status values."""
 TRANSACTION_STATUS_IDLE    = 0

psycopg/connection.h

@@ -53,11 +53,10 @@ extern "C" {
 #define ASYNC_READ  1
 #define ASYNC_WRITE 2
 
-/* polling result, try to keep in sync with PostgresPollingStatusType from
+/* polling result */
-   libpq-fe.h */
+#define PSYCO_POLL_OK    0
 #define PSYCO_POLL_READ  1
 #define PSYCO_POLL_WRITE 2
-#define PSYCO_POLL_OK    3
 
 /* Hard limit on the notices stored by the Python connection */
 #define CONN_NOTICES_LIMIT 50

psycopg/cursor.h

@@ -62,10 +62,10 @@ typedef struct {
     PyObject   *pgstatus;  /* last message from the server after an execute */
     Oid         lastoid;   /* last oid from an insert or InvalidOid */
 
-    PyObject *casts;      /* an array (tuple) of typecast functions */
+    PyObject *casts;       /* an array (tuple) of typecast functions */
-    PyObject *caster;     /* the current typecaster object */
+    PyObject *caster;      /* the current typecaster object */
 
-    PyObject *copyfile;   /* file-like used during COPY TO/FROM ops */
+    PyObject  *copyfile;   /* file-like used during COPY TO/FROM ops */
     Py_ssize_t copysize;   /* size of the copy buffer during COPY TO/FROM ops */
 #define DEFAULT_COPYSIZE 16384
 #define DEFAULT_COPYBUFF  8132

psycopg/cursor_int.c

@@ -141,9 +141,16 @@ curs_poll_fetch(cursorObject *self)
         return PyInt_FromLong(PSYCO_POLL_READ);
     }
 
-    /* data has arrived, try to fetch all of it or, if it failed, tell the
+    /* try to fetch the data only if this was a poll following a read
-       user to wait more */
+       request; else just return POLL_OK to the user: this is necessary
-    last_result = curs_get_last_result(self);
+       because of asynchronous NOTIFYs that can be sent by the backend
+       even if the user didn't asked for them */
+
+    if (self->conn->async_status == ASYNC_READ)
+        last_result = curs_get_last_result(self);
+    else
+        last_result = 0;
+
     if (last_result == 0) {
         Dprintf("cur_poll_fetch: returning %d", PSYCO_POLL_OK);
         return PyInt_FromLong(PSYCO_POLL_OK);

psycopg/cursor_type.c

@@ -1485,14 +1485,9 @@ psyco_curs_poll(cursorObject *self)
     if (self->conn->async_status == ASYNC_WRITE) {
         return curs_poll_send(self);
     }
-    else if (self->conn->async_status == ASYNC_READ) {
+    else  {
         return curs_poll_fetch(self);
     }
-    else {
-        PyErr_Format(OperationalError, "unexpected execution status: %d",
-                     self->conn->async_status);
-        return NULL;
-    }
 }
 
 /* extension: closed - return true if cursor is closed*/