[gthumb] catalogs: correctly load empty catalogs

[Paolo Bacchilega <paobac src gnome org>]

commit 85f5fc57a3b360480ec0e82a0b1052444e62a179
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Mon Jan 20 09:56:15 2020 +0100

    catalogs: correctly load empty catalogs
    
    Do not return a null catalog if the catalog file is empty.

 extensions/catalogs/dlg-catalog-properties.c   |  2 +-
 extensions/catalogs/gth-catalog.c              | 12 +++++++++---
 extensions/catalogs/gth-file-source-catalogs.c | 10 ++++------
 3 files changed, 14 insertions(+), 10 deletions(-)
---
diff --git a/extensions/catalogs/dlg-catalog-properties.c b/extensions/catalogs/dlg-catalog-properties.c
index b2f20f68..88c1d4d1 100644
--- a/extensions/catalogs/dlg-catalog-properties.c
+++ b/extensions/catalogs/dlg-catalog-properties.c
@@ -150,7 +150,7 @@ catalog_ready_cb (GObject  *object,
 {
        DialogData *data = user_data;
 
-       if ((error != NULL) || (object == NULL)) {
+       if (error != NULL) {
                _gtk_error_dialog_from_gerror_show (GTK_WINDOW(data->browser), _("Could not load the 
catalog"), error);
                gtk_widget_destroy (data->dialog);
                return;
diff --git a/extensions/catalogs/gth-catalog.c b/extensions/catalogs/gth-catalog.c
index 9d9d940a..ff310187 100644
--- a/extensions/catalogs/gth-catalog.c
+++ b/extensions/catalogs/gth-catalog.c
@@ -927,8 +927,9 @@ gth_catalog_update_standard_attributes (GFile     *file,
 
 
 typedef struct {
-       ReadyCallback ready_func;
-       gpointer      user_data;
+       GFile         *file;
+       ReadyCallback  ready_func;
+       gpointer       user_data;
 } LoadData;
 
 
@@ -941,12 +942,16 @@ load__catalog_buffer_ready_cb (void     **buffer,
        LoadData   *load_data = user_data;
        GthCatalog *catalog;
 
-       if (error == NULL)
+       if (error == NULL) {
                catalog = gth_catalog_new_from_data (*buffer, count, &error);
+               if (catalog == NULL)
+                       catalog = gth_catalog_new_for_file (load_data->file);
+       }
        else
                catalog = NULL;
        load_data->ready_func (G_OBJECT (catalog), error, load_data->user_data);
 
+       g_object_unref (load_data->file);
        g_free (load_data);
 }
 
@@ -961,6 +966,7 @@ gth_catalog_load_from_file_async (GFile         *file,
        GFile    *gio_file;
 
        load_data = g_new0 (LoadData, 1);
+       load_data->file = g_object_ref (file);
        load_data->ready_func = ready_func;
        load_data->user_data = user_data;
 
diff --git a/extensions/catalogs/gth-file-source-catalogs.c b/extensions/catalogs/gth-file-source-catalogs.c
index 9107eebd..02dc2147 100644
--- a/extensions/catalogs/gth-file-source-catalogs.c
+++ b/extensions/catalogs/gth-file-source-catalogs.c
@@ -349,10 +349,8 @@ read_metadata_catalog_ready_cb (GObject  *object,
        if (error != NULL)
                g_clear_error (&error);
 
-       if (object != NULL) {
-               gth_catalog_update_metadata (GTH_CATALOG (object), read_metadata->file_data);
-               g_object_unref (object);
-       }
+       gth_catalog_update_metadata (GTH_CATALOG (object), read_metadata->file_data);
+       g_object_unref (object);
 
        read_metadata->callback (G_OBJECT (read_metadata->file_source), error, read_metadata->data);
        read_metadata_free (read_metadata);
@@ -820,7 +818,7 @@ catalog_ready_cb (GObject  *catalog,
        gsize       size;
        GFile      *gio_file;
 
-       if ((error != NULL) || (catalog == NULL)) {
+       if (error != NULL) {
                cod->ready_callback (G_OBJECT (cod->file_source), error, cod->user_data);
                copy_op_data_free (cod);
                return;
@@ -1235,7 +1233,7 @@ reorder_catalog_ready_cb (GObject  *object,
        gsize        size;
        GFile       *gio_file;
 
-       if ((error != NULL) || (object == NULL)) {
+       if (error != NULL) {
                reorder_data->callback (G_OBJECT (reorder_data->file_source), error, reorder_data->data);
                reorder_data_free (reorder_data);
                return;