[PATCH] core: prefer g_task_return_error_if_cancelled() than custom errors

[Aleksander Morgado]

When the GCancellable is added to the GTask, we can use a single
method call to check for the task being cancelled, and complete it
right away if so.

This patch also clears up the logic in the Novatel plugin, where the
code was trying to return "TRUE" when the task was cancelled, but
wouldn't work as the check-cancellable flag in the GTask is TRUE by
default (i.e. when completing the GTask, if it was cancelled, a
G_IO_ERROR_CANCELLED would be returned by default, regardless of any
other return value set).

This patch also introduces a small variation of the logic in the
Cinterion plugin: instead of running SWWAN=0 before completing the
async action, the command is now sent just after completion of the
async action. This shouldn't be an issue, as the SWWAN result itself
is ignored.
---

Hey Ben,

What do you think of these changes? I believe we should start using this where applicable, instead of the custom checks and errors.

---
 plugins/cinterion/mm-broadband-bearer-cinterion.c | 7 ++-----
 plugins/novatel/mm-common-novatel.c               | 3 +--
 src/mm-auth-provider-polkit.c                     | 6 +-----
 src/mm-iface-modem-signal.c                       | 6 +-----
 4 files changed, 5 insertions(+), 17 deletions(-)

diff --git a/plugins/cinterion/mm-broadband-bearer-cinterion.c b/plugins/cinterion/mm-broadband-bearer-cinterion.c
index 741d2935..a1c699e9 100644
--- a/plugins/cinterion/mm-broadband-bearer-cinterion.c
+++ b/plugins/cinterion/mm-broadband-bearer-cinterion.c
@@ -343,10 +343,6 @@ handle_cancel_dial (GTask *task)
                                    NULL,
                                    NULL);
     g_free (command);
-
-    g_task_return_new_error (task, MM_CORE_ERROR, MM_CORE_ERROR_CANCELLED,
-                             "Connection operation has been cancelled");
-    g_object_unref (task);
 }

 static void
@@ -357,8 +353,9 @@ dial_3gpp_context_step (GTask *task)
     ctx = (Dial3gppContext *) g_task_get_task_data (task);

     /* Check for cancellation */
-    if (g_cancellable_is_cancelled (g_task_get_cancellable (task))) {
+    if (g_task_return_error_if_cancelled (task)) {
         handle_cancel_dial (task);
+        g_object_unref (task);
         return;
     }

diff --git a/plugins/novatel/mm-common-novatel.c b/plugins/novatel/mm-common-novatel.c
index 96d845f1..f8c78f51 100644
--- a/plugins/novatel/mm-common-novatel.c
+++ b/plugins/novatel/mm-common-novatel.c
@@ -87,10 +87,9 @@ custom_init_step (GTask *task)
     ctx = g_task_get_task_data (task);

     /* If cancelled, end */
-    if (g_cancellable_is_cancelled (g_task_get_cancellable (task))) {
+    if (g_task_return_error_if_cancelled (task)) {
         mm_dbg ("(Novatel) no need to keep on running custom init in (%s)",
                 mm_port_get_device (MM_PORT (ctx->port)));
-        g_task_return_boolean (task, TRUE);
         g_object_unref (task);
         return;
     }
diff --git a/src/mm-auth-provider-polkit.c b/src/mm-auth-provider-polkit.c
index 3b9b4250..7e88d67c 100644
--- a/src/mm-auth-provider-polkit.c
+++ b/src/mm-auth-provider-polkit.c
@@ -72,11 +72,7 @@ check_authorization_ready (PolkitAuthority *authority,
     GError *error = NULL;
     AuthorizeContext *ctx;

-    if (g_cancellable_is_cancelled (g_task_get_cancellable (task))) {
-        g_task_return_new_error (task,
-                                 MM_CORE_ERROR,
-                                 MM_CORE_ERROR_CANCELLED,
-                                 "PolicyKit authorization attempt cancelled");
+    if (g_task_return_error_if_cancelled (task)) {
         g_object_unref (task);
         return;
     }
diff --git a/src/mm-iface-modem-signal.c b/src/mm-iface-modem-signal.c
index 9751b5d6..99096a95 100644
--- a/src/mm-iface-modem-signal.c
+++ b/src/mm-iface-modem-signal.c
@@ -418,11 +418,7 @@ interface_initialization_step (GTask *task)
     InitializationContext *ctx;

     /* Don't run new steps if we're cancelled */
-    if (g_cancellable_is_cancelled (g_task_get_cancellable (task))) {
-        g_task_return_new_error (task,
-                                 MM_CORE_ERROR,
-                                 MM_CORE_ERROR_CANCELLED,
-                                 "Interface initialization cancelled");
+    if (g_task_return_error_if_cancelled (task)) {
         g_object_unref (task);
         return;
     }
--
2.12.2