[ModemManager] [PATCH] serial: report port-not-open in queueing commands via callback instead of just returning.

[Nathan Williams <njw google com>]

This is a followup to my previous change here; the port-not-open
situation is better treated as a manageable error condition rather
than a programming error.

    - Nathan

From cec1bb628cd736fd0ac251e77e87f970cd78a4fb Mon Sep 17 00:00:00 2001
From: Nathan Williams <njw chromium org>
Date: Wed, 23 Nov 2011 16:16:20 -0500
Subject: [PATCH] serial: report port-not-open in queueing commands via callback instead of just returning.

This permits routines like mm-generic-gsm.c:simple_get_status() to
work again, as their callbacks get the error they are expecting. To
make this work, adapt get_csq_done() to handle a NULL response when
error is set, and make sure that multiple errors don't step on each
other in the mm_callback_info_chain() sequence created by
simple_get_status().

Change-Id: Ie3a72b1ce71b7f117e8b1f3da7a406c4d2da9e02
---
 src/mm-generic-gsm.c |   14 +++++++++++---
 src/mm-serial-port.c |   10 +++++++++-
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/mm-generic-gsm.c b/src/mm-generic-gsm.c
index d7a232e..d8ba4be 100644
--- a/src/mm-generic-gsm.c
+++ b/src/mm-generic-gsm.c
@@ -4187,7 +4187,7 @@ get_csq_done (MMAtSerialPort *port,
               gpointer user_data)
 {
     MMCallbackInfo *info = (MMCallbackInfo *) user_data;
-    char *reply = response->str;
+    char *reply;
     gboolean parsed = FALSE;
 
     /* If the modem has already been removed, return without
@@ -4200,6 +4200,7 @@ get_csq_done (MMAtSerialPort *port,
         goto done;
     }
 
+    reply = response->str;
     if (!strncmp (reply, "+CSQ: ", 6)) {
         /* Got valid reply */
         int quality;
@@ -5596,6 +5597,9 @@ simple_status_got_signal_quality (MMModem *modem,
     if (!error) {
         properties = (GHashTable *) mm_callback_info_get_data (info, SS_HASH_TAG);
         g_hash_table_insert (properties, "signal_quality", simple_uint_value (result));
+    } else {
+        g_clear_error (&info->error);
+        info->error = g_error_copy (error);
     }
     mm_callback_info_chain_complete_one (info);
 }
@@ -5612,6 +5616,9 @@ simple_status_got_band (MMModem *modem,
     if (!error) {
         properties = (GHashTable *) mm_callback_info_get_data (info, SS_HASH_TAG);
         g_hash_table_insert (properties, "band", simple_uint_value (result));
+    } else {
+        g_clear_error (&info->error);
+        info->error = g_error_copy (error);
     }
     mm_callback_info_chain_complete_one (info);
 }
@@ -5631,9 +5638,10 @@ simple_status_got_reg_info (MMModemGsmNetwork *modem,
     if (!modem || mm_callback_info_check_modem_removed (info))
         return;
 
-    if (error)
+    if (error) {
+        g_clear_error (&info->error);
         info->error = g_error_copy (error);
-    else {
+    } else {
         properties = (GHashTable *) mm_callback_info_get_data (info, SS_HASH_TAG);
 
         g_hash_table_insert (properties, "registration_status", simple_uint_value (status));
diff --git a/src/mm-serial-port.c b/src/mm-serial-port.c
index 2d07214..ad5cd91 100644
--- a/src/mm-serial-port.c
+++ b/src/mm-serial-port.c
@@ -969,9 +969,17 @@ internal_queue_command (MMSerialPort *self,
     MMQueueData *info;
 
     g_return_if_fail (MM_IS_SERIAL_PORT (self));
-    g_return_if_fail (priv->open_count > 0);
     g_return_if_fail (command != NULL);
 
+    if (!(priv->open_count > 0)) {
+        GError *error = g_error_new_literal (MM_SERIAL_ERROR,
+                                             MM_SERIAL_ERROR_SEND_FAILED,
+                                             "Sending command failed: device is not enabled");
+        callback (self, NULL, error, user_data);
+        g_error_free (error);
+        return;
+    }
+
     info = g_slice_new0 (MMQueueData);
     if (take_command)
         info->command = command;
-- 
1.7.3.1