[libgda] Avoid calling g_main_context_unref(NULL)

[Vivien Malerba <vivien src gnome org>]

commit d5146ee49e704fa4f63394a1310242913e6ae2b3
Author: Vivien Malerba <malerba gnome-db org>
Date:   Sun May 18 23:38:26 2014 +0200

    Avoid calling g_main_context_unref(NULL)

 libgda/gda-blob-op.c     |   12 ++++++++----
 libgda/gda-data-select.c |   18 ++++++++++++------
 2 files changed, 20 insertions(+), 10 deletions(-)
---
diff --git a/libgda/gda-blob-op.c b/libgda/gda-blob-op.c
index 004328b..b4b367a 100644
--- a/libgda/gda-blob-op.c
+++ b/libgda/gda-blob-op.c
@@ -232,7 +232,8 @@ gda_blob_op_get_length (GdaBlobOp *op)
                gpointer callval;
                gda_worker_do_job (op->priv->worker, context, 0, &callval, NULL,
                                   (GdaWorkerFunc) worker_get_length, (gpointer) &data, NULL, NULL, NULL);
-               g_main_context_unref (context);
+               if (context)
+                       g_main_context_unref (context);
 
                gda_lockable_unlock ((GdaLockable*) op->priv->cnc); /* CNC UNLOCK */
 
@@ -297,7 +298,8 @@ gda_blob_op_read (GdaBlobOp *op, GdaBlob *blob, glong offset, glong size)
                gpointer callval;
                gda_worker_do_job (op->priv->worker, context, 0, &callval, NULL,
                                   (GdaWorkerFunc) worker_read, (gpointer) &data, NULL, NULL, NULL);
-               g_main_context_unref (context);
+               if (context)
+                       g_main_context_unref (context);
 
                gda_lockable_unlock ((GdaLockable*) op->priv->cnc); /* CNC UNLOCK */
 
@@ -387,7 +389,8 @@ gda_blob_op_write (GdaBlobOp *op, GdaBlob *blob, glong offset)
                gpointer callval;
                gda_worker_do_job (op->priv->worker, context, 0, &callval, NULL,
                                   (GdaWorkerFunc) worker_write, (gpointer) &data, NULL, NULL, NULL);
-               g_main_context_unref (context);
+               if (context)
+                       g_main_context_unref (context);
 
                gda_lockable_unlock ((GdaLockable*) op->priv->cnc); /* CNC UNLOCK */
 
@@ -449,7 +452,8 @@ gda_blob_op_write_all (GdaBlobOp *op, GdaBlob *blob)
                        gpointer callval;
                        gda_worker_do_job (op->priv->worker, context, 0, &callval, NULL,
                                           (GdaWorkerFunc) worker_write_all, (gpointer) &data, NULL, NULL, 
NULL);
-                       g_main_context_unref (context);
+                       if (context)
+                               g_main_context_unref (context);
 
                        gda_lockable_unlock ((GdaLockable*) op->priv->cnc); /* CNC UNLOCK */
 
diff --git a/libgda/gda-data-select.c b/libgda/gda-data-select.c
index 674129d..47d1c8d 100644
--- a/libgda/gda-data-select.c
+++ b/libgda/gda-data-select.c
@@ -3913,7 +3913,8 @@ _gda_data_select_fetch_nb_rows (GdaDataSelect *model)
                nbrows = *result;
                g_slice_free (gint, result);
        }
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
 
        return nbrows;
 }
@@ -3952,7 +3953,8 @@ _gda_data_select_fetch_random  (GdaDataSelect *model, GdaRow **prow, gint rownum
        gpointer result;
        gda_worker_do_job (model->priv->worker, context, 0, &result, NULL,
                           (GdaWorkerFunc) worker_fetch_random, &jdata, NULL, NULL, error);
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
        return result ? TRUE : FALSE;
 }
 
@@ -3979,7 +3981,8 @@ _gda_data_select_store_all (GdaDataSelect *model, GError **error)
        gpointer result;
        gda_worker_do_job (model->priv->worker, context, 0, (gpointer) &result, NULL,
                           (GdaWorkerFunc) worker_store_all, model, NULL, NULL, NULL);
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
        return result ? TRUE : FALSE;
 }
 
@@ -4011,7 +4014,8 @@ _gda_data_select_fetch_next    (GdaDataSelect *model, GdaRow **prow, gint rownum
        gpointer result;
        gda_worker_do_job (model->priv->worker, context, 0, &result, NULL,
                           (GdaWorkerFunc) worker_fetch_next, &jdata, NULL, NULL, error);
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
        return result ? TRUE : FALSE;
 }
 
@@ -4043,7 +4047,8 @@ _gda_data_select_fetch_prev    (GdaDataSelect *model, GdaRow **prow, gint rownum
        gpointer result;
        gda_worker_do_job (model->priv->worker, context, 0, &result, NULL,
                           (GdaWorkerFunc) worker_fetch_prev, &jdata, NULL, NULL, error);
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
        return result ? TRUE : FALSE;
 }
 
@@ -4075,6 +4080,7 @@ _gda_data_select_fetch_at      (GdaDataSelect *model, GdaRow **prow, gint rownum
        gpointer result;
        gda_worker_do_job (model->priv->worker, context, 0, &result, NULL,
                           (GdaWorkerFunc) worker_fetch_at, &jdata, NULL, NULL, error);
-       g_main_context_unref (context);
+       if (context)
+               g_main_context_unref (context);
        return result ? TRUE : FALSE;
 }