base-modem: allow parallel Enable() and Disable() requests

If additional Enable() requests are received while one is already
ongoing, we queue them and will end up completing all with the same
result once the first one finishes.

Same logic also for Disable().

https://gitlab.freedesktop.org/mobile-broadband/ModemManager/issues/8

src/mm-base-modem.c

@@ -93,6 +93,10 @@ struct _MMBaseModemPrivate {
     MMPortSerialAt *gps_control;
     MMPortSerialGps *gps;
 
+    /* Support for parallel enable/disable operations */
+    GList *enable_tasks;
+    GList *disable_tasks;
+
 #if defined WITH_QMI
     /* QMI ports */
     GList *qmi;
@@ -318,7 +322,31 @@ mm_base_modem_disable_finish (MMBaseModem *self,
                               GAsyncResult  *res,
                               GError       **error)
 {
-    return MM_BASE_MODEM_GET_CLASS (self)->disable_finish (self, res, error);
+    return g_task_propagate_boolean (G_TASK (res), error);
+}
+
+static void
+disable_ready (MMBaseModem  *self,
+               GAsyncResult *res)
+{
+    GError *error = NULL;
+    GList  *l;
+    GList  *disable_tasks;
+
+    g_assert (self->priv->disable_tasks);
+    disable_tasks = self->priv->disable_tasks;
+    self->priv->disable_tasks = NULL;
+
+    MM_BASE_MODEM_GET_CLASS (self)->disable_finish (self, res, &error);
+    for (l = disable_tasks; l; l = g_list_next (l)) {
+        if (error)
+            g_task_return_error (G_TASK (l->data), g_error_copy (error));
+        else
+            g_task_return_boolean (G_TASK (l->data), TRUE);
+    }
+    g_clear_error (&error);
+
+    g_list_free_full (disable_tasks, (GDestroyNotify)g_object_unref);
 }
 
 void
@@ -326,14 +354,27 @@ mm_base_modem_disable (MMBaseModem *self,
                        GAsyncReadyCallback  callback,
                        gpointer             user_data)
 {
+    GTask    *task;
+    gboolean  run_disable;
+
     g_assert (MM_BASE_MODEM_GET_CLASS (self)->disable != NULL);
     g_assert (MM_BASE_MODEM_GET_CLASS (self)->disable_finish != NULL);
 
+    /* If the list of disable tasks is empty, we need to run */
+    run_disable = !self->priv->disable_tasks;
+
+    /* Store task */
+    task = g_task_new (self, self->priv->cancellable, callback, user_data);
+    self->priv->disable_tasks = g_list_append (self->priv->disable_tasks, task);
+
+    if (!run_disable)
+        return;
+
     MM_BASE_MODEM_GET_CLASS (self)->disable (
         self,
         self->priv->cancellable,
-        callback,
-        user_data);
+        (GAsyncReadyCallback) disable_ready,
+        NULL);
 }
 
 gboolean
@@ -341,7 +382,31 @@ mm_base_modem_enable_finish (MMBaseModem *self,
                              GAsyncResult  *res,
                              GError       **error)
 {
-    return MM_BASE_MODEM_GET_CLASS (self)->enable_finish (self, res, error);
+    return g_task_propagate_boolean (G_TASK (res), error);
+}
+
+static void
+enable_ready (MMBaseModem  *self,
+              GAsyncResult *res)
+{
+    GError *error = NULL;
+    GList  *l;
+    GList  *enable_tasks;
+
+    g_assert (self->priv->enable_tasks);
+    enable_tasks = self->priv->enable_tasks;
+    self->priv->enable_tasks = NULL;
+
+    MM_BASE_MODEM_GET_CLASS (self)->enable_finish (self, res, &error);
+    for (l = enable_tasks; l; l = g_list_next (l)) {
+        if (error)
+            g_task_return_error (G_TASK (l->data), g_error_copy (error));
+        else
+            g_task_return_boolean (G_TASK (l->data), TRUE);
+    }
+    g_clear_error (&error);
+
+    g_list_free_full (enable_tasks, (GDestroyNotify)g_object_unref);
 }
 
 void
@@ -349,14 +414,27 @@ mm_base_modem_enable (MMBaseModem *self,
                       GAsyncReadyCallback  callback,
                       gpointer             user_data)
 {
+    GTask    *task;
+    gboolean  run_enable;
+
     g_assert (MM_BASE_MODEM_GET_CLASS (self)->enable != NULL);
     g_assert (MM_BASE_MODEM_GET_CLASS (self)->enable_finish != NULL);
 
+    /* If the list of enable tasks is empty, we need to run */
+    run_enable = !self->priv->enable_tasks;
+
+    /* Store task */
+    task = g_task_new (self, self->priv->cancellable, callback, user_data);
+    self->priv->enable_tasks = g_list_append (self->priv->enable_tasks, task);
+
+    if (!run_enable)
+        return;
+
     MM_BASE_MODEM_GET_CLASS (self)->enable (
         self,
         self->priv->cancellable,
-        callback,
-        user_data);
+        (GAsyncReadyCallback) enable_ready,
+        NULL);
 }
 
 gboolean
@@ -1423,6 +1501,9 @@ finalize (GObject *object)
      * mm_auth_provider_cancel_for_owner (self->priv->authp, object);
     */
 
+    g_assert (!self->priv->enable_tasks);
+    g_assert (!self->priv->disable_tasks);
+
     mm_dbg ("Modem (%s) '%s' completely disposed",
             self->priv->plugin,
             self->priv->device);

src/mm-broadband-modem.c

@@ -10006,11 +10006,7 @@ enable (MMBaseModem *self,
         break;
 
     case MM_MODEM_STATE_ENABLING:
-        g_task_return_new_error (task,
-                                 MM_CORE_ERROR,
-                                 MM_CORE_ERROR_IN_PROGRESS,
-                                 "Cannot enable modem: "
-                                 "already being enabled");
+        g_assert_not_reached ();
         break;
 
     case MM_MODEM_STATE_ENABLED: