[evolution-data-server] Add error checks around factory subprocess backend loading

[Milan Crha <mcrha src gnome org>]

commit a722c400b0e6f3edd06e390f292a1c3ee859d822
Author: Milan Crha <mcrha redhat com>
Date:   Thu Apr 28 14:55:58 2016 +0200

    Add error checks around factory subprocess backend loading
    
    Instead of crashing, report errors to the caller.

 .../libedata-book/e-subprocess-book-factory.c      |   10 ++++++----
 calendar/libedata-cal/e-subprocess-cal-factory.c   |   10 ++++++----
 libebackend/e-subprocess-factory.c                 |   17 +++++++++++++----
 3 files changed, 25 insertions(+), 12 deletions(-)
---
diff --git a/addressbook/libedata-book/e-subprocess-book-factory.c 
b/addressbook/libedata-book/e-subprocess-book-factory.c
index bef12d6..ae4beea 100644
--- a/addressbook/libedata-book/e-subprocess-book-factory.c
+++ b/addressbook/libedata-book/e-subprocess-book-factory.c
@@ -123,19 +123,21 @@ subprocess_book_factory_ref_backend (ESourceRegistry *registry,
                                     ESource *source,
                                     const gchar *backend_factory_type_name)
 {
-       EBookBackend *backend;
        EBookBackendFactoryClass *backend_factory_class;
        GType backend_factory_type;
 
        backend_factory_type = g_type_from_name (backend_factory_type_name);
+       if (!backend_factory_type)
+               return NULL;
+
        backend_factory_class = g_type_class_ref (backend_factory_type);
+       if (!backend_factory_class)
+               return NULL;
 
-       backend = g_object_new (
+       return g_object_new (
                backend_factory_class->backend_type,
                "registry", registry,
                "source", source, NULL);
-
-       return E_BACKEND (backend);
 }
 
 static void
diff --git a/calendar/libedata-cal/e-subprocess-cal-factory.c 
b/calendar/libedata-cal/e-subprocess-cal-factory.c
index a0288ac..8d94929 100644
--- a/calendar/libedata-cal/e-subprocess-cal-factory.c
+++ b/calendar/libedata-cal/e-subprocess-cal-factory.c
@@ -97,20 +97,22 @@ subprocess_cal_factory_ref_backend (ESourceRegistry *registry,
                                     ESource *source,
                                     const gchar *backend_factory_type_name)
 {
-       ECalBackend *backend;
        ECalBackendFactoryClass *backend_factory_class;
        GType backend_factory_type;
 
        backend_factory_type = g_type_from_name (backend_factory_type_name);
+       if (!backend_factory_type)
+               return NULL;
+
        backend_factory_class = g_type_class_ref (backend_factory_type);
+       if (!backend_factory_class)
+               return NULL;
 
-       backend = g_object_new (
+       return g_object_new (
                backend_factory_class->backend_type,
                "kind", backend_factory_class->component_kind,
                "registry", registry,
                "source", source, NULL);
-
-       return E_BACKEND (backend);
 }
 
 static void
diff --git a/libebackend/e-subprocess-factory.c b/libebackend/e-subprocess-factory.c
index 8a935ae..d59d9bc 100644
--- a/libebackend/e-subprocess-factory.c
+++ b/libebackend/e-subprocess-factory.c
@@ -267,13 +267,19 @@ e_subprocess_factory_ref_initable_backend (ESubprocessFactory *subprocess_factor
        backend = g_hash_table_lookup (priv->backends, uid);
        if (backend != NULL) {
                g_object_ref (backend);
-
                goto exit;
        }
 
        module = g_hash_table_lookup (priv->modules, module_filename);
        if (module == NULL) {
                module = e_module_load_file (module_filename);
+               if (!module) {
+                       g_set_error (
+                               error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
+                               _("Module '%s' for source UID '%s' cannot be loaded"), module_filename, uid);
+                       goto exit;
+               }
+
                g_hash_table_insert (priv->modules, g_strdup (module_filename), module);
        }
 
@@ -288,11 +294,14 @@ e_subprocess_factory_ref_initable_backend (ESubprocessFactory *subprocess_factor
 
        class = E_SUBPROCESS_FACTORY_GET_CLASS (subprocess_factory);
 
-       backend = class->ref_backend (
-               registry, source, backend_factory_type_name);
+       backend = class->ref_backend (registry, source, backend_factory_type_name);
 
-       if (backend == NULL)
+       if (backend == NULL) {
+               g_set_error (
+                       error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND,
+                       _("Failed to create backend of type '%s' for source UID '%s'"), 
backend_factory_type_name, uid);
                goto exit;
+       }
 
        if (G_IS_INITABLE (backend)) {
                GInitable *initable = G_INITABLE (backend);