[tracker/wip/carlosg/domain-ontologies: 105/124] libtracker-common: Use XDG_DATA_DIRS to find domain ontology definitions

[Carlos Garnacho <carlosg src gnome org>]

commit ef58c5b5e815381590d5830088d909f224df95de
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Jun 21 13:59:23 2017 +0200

    libtracker-common: Use XDG_DATA_DIRS to find domain ontology definitions

 src/libtracker-common/tracker-domain-ontology.c |   56 +++++++++++++++++++---
 1 files changed, 48 insertions(+), 8 deletions(-)
---
diff --git a/src/libtracker-common/tracker-domain-ontology.c b/src/libtracker-common/tracker-domain-ontology.c
index 122f0b2..2ce03ef 100644
--- a/src/libtracker-common/tracker-domain-ontology.c
+++ b/src/libtracker-common/tracker-domain-ontology.c
@@ -70,6 +70,8 @@ struct {
 #define ONTOLOGY_NAME_KEY "OntologyName"
 #define DOMAIN_KEY "Domain"
 
+#define DEFAULT_RULE "default.rule"
+
 static void tracker_domain_ontology_initable_iface_init (GInitableIface *iface);
 
 G_DEFINE_TYPE_WITH_CODE (TrackerDomainOntology, tracker_domain_ontology, G_TYPE_OBJECT,
@@ -256,6 +258,33 @@ key_file_get_location (GKeyFile     *key_file,
        return file;
 }
 
+static gchar *
+find_rule_in_data_dirs (const gchar *name)
+{
+       const gchar* const *data_dirs;
+       gchar *path, *rule_name;
+       guint i;
+
+       data_dirs = g_get_system_data_dirs ();
+       rule_name = g_strconcat (name, ".rule", NULL);
+
+       for (i = 0; data_dirs[i] != NULL; i++) {
+               path = g_build_filename (data_dirs[i],
+                                        "tracker", "domain-ontologies",
+                                        rule_name, NULL);
+               if (g_file_test (path, G_FILE_TEST_IS_REGULAR)) {
+                       g_free (rule_name);
+                       return path;
+               }
+
+               g_free (path);
+       }
+
+       g_free (rule_name);
+
+       return NULL;
+}
+
 static gboolean
 tracker_domain_ontology_initable_init (GInitable     *initable,
                                        GCancellable  *cancellable,
@@ -264,19 +293,29 @@ tracker_domain_ontology_initable_init (GInitable     *initable,
        TrackerDomainOntology *domain_ontology;
        TrackerDomainOntologyPrivate *priv;
        GError *inner_error = NULL;
-       GKeyFile *key_file;
-       gchar *rulename, *path;
+       GKeyFile *key_file = NULL;
+       gchar *path;
 
        domain_ontology = TRACKER_DOMAIN_ONTOLOGY (initable);
        priv = tracker_domain_ontology_get_instance_private (domain_ontology);
 
-       rulename = g_strconcat (priv->name ? priv->name : "default", ".rule", NULL);
-       path = g_build_filename (SHAREDIR, "tracker", "domain-ontologies",
-                                rulename, NULL);
+       if (priv->name) {
+               path = find_rule_in_data_dirs (priv->name);
+
+               if (!path) {
+                       inner_error = g_error_new (G_KEY_FILE_ERROR,
+                                                  G_KEY_FILE_ERROR_NOT_FOUND,
+                                                  "Could not find rule '%s' in data dirs",
+                                                  priv->name);
+                       goto end;
+               }
+       } else {
+               path = g_build_filename (SHAREDIR, "tracker", "domain-ontologies",
+                                        DEFAULT_RULE, NULL);
+       }
+
        key_file = g_key_file_new ();
        g_key_file_load_from_file (key_file, path, G_KEY_FILE_NONE, &inner_error);
-
-       g_free (rulename);
        g_free (path);
 
        if (inner_error)
@@ -329,7 +368,8 @@ tracker_domain_ontology_initable_init (GInitable     *initable,
        }
 
 end:
-       g_key_file_free (key_file);
+       if (key_file)
+               g_key_file_free (key_file);
 
        if (inner_error) {
                g_propagate_error (error, inner_error);