Fix postgres notification support in the QPSQLDriver.

This patch fixes a critical bug in the qsqlpsql driver where
notifications aren't delivered when received. Any blocking libpq
function(specifically PQexec) will read all the incoming data
from the socket, including any pending notifications. This would
cause the socket notifier to never be fired for incoming
notifications that are already queued inside libpq. The qsqldriver
test case was skipping the postgres notification test because of
this bug, now its enabled and passing. In order to fix this
bug I made a wrapper function for PQexec in QPSQLDriverPrivate
that calls _q_handleNotification via QMetaObject::callMethod
QueuedConnection in order to deliver pending notifications
when control returns to the event loop. I also added a flag
to ensure only one call is made each time the event loop is
entered.

This backport omits the changes to the NotificationSource version
of the "notification" signal that were included in the original
commit, since NotificationSource itself has not yet been introduced
into Qt4.

(Backport of qtbase aea684506945a12312fc05fb3bb4f549da93f7f5)

Change-Id: I19f5297094ae7ae46bfb0717e4fca744d69f7b92
Reviewed-by: Mark Brand <mabrand@mabrand.nl>

1 files changed, 0 insertions, 4 deletions

diff --git a/tests/auto/qsqldatabase/tst_qsqldatabase.cpp b/tests/auto/qsqldatabase/tst_qsqldatabase.cpp
index fda678b..bbd08bd 100644
--- a/tests/auto/qsqldatabase/tst_qsqldatabase.cpp
+++ b/tests/auto/qsqldatabase/tst_qsqldatabase.cpp
@@ -2415,10 +2415,6 @@ void tst_QSqlDatabase::eventNotificationPSQL()
     QSqlDatabase db = QSqlDatabase::database(dbName);
     CHECK_DATABASE(db);
 
-#if defined(Q_OS_LINUX)
-    QSKIP( "Event support doesn't work on linux", SkipAll );
-#endif
-
     QSqlQuery query(db);
     QString procedureName = qTableName("posteventProc", __FILE__);