miner-fs: Give clearer warning when XDG user dirs are unconfigured

If Tracker can't resolve special dirs like &DOCUMENTS to real path
names, it now gives a warning like this:

    (tracker-miner-fs:7207): Tracker-WARNING **: Unable to get XDG user
    directory path for special directory &DOCUMENTS. Ignoring this
    location.

Previously (since commit 5f06c134f4f6da02027c813322e13c220b51cd0a) the
user would see this rather more scary output:

    (tracker-miner-fs:6046): GLib-GIO-CRITICAL **: g_file_new_for_path:
    assertion 'path != NULL' failed

    (tracker-miner-fs:6046): GLib-GIO-CRITICAL **: g_file_equal: assertion
    'G_IS_FILE (file1)' failed

    (tracker-miner-fs:6046): GLib-GObject-CRITICAL **: g_object_unref:
    assertion 'G_IS_OBJECT (object)' failed

This situation is rare (you need to manually change or break
XDG_CONFIG_HOME to really see it) but it's always nice to avoid showing
critical errors!

2 files changed, 66 insertions, 43 deletions

diff --git a/src/libtracker-common/tracker-file-utils.c b/src/libtracker-common/tracker-file-utils.c
index 22322d991..ad9f6b348 100644
--- a/src/libtracker-common/tracker-file-utils.c
+++ b/src/libtracker-common/tracker-file-utils.c
@@ -480,9 +480,67 @@ tracker_path_list_filter_duplicates (GSList      *roots,
 	return new_list;
 }
 
+const struct {
+	const gchar *symbol;
+	GUserDirectory user_dir;
+} special_dirs[] = {
+	{"&DESKTOP",      G_USER_DIRECTORY_DESKTOP},
+	{"&DOCUMENTS",    G_USER_DIRECTORY_DOCUMENTS},
+	{"&DOWNLOAD",     G_USER_DIRECTORY_DOWNLOAD},
+	{"&MUSIC",        G_USER_DIRECTORY_MUSIC},
+	{"&PICTURES",     G_USER_DIRECTORY_PICTURES},
+	{"&PUBLIC_SHARE", G_USER_DIRECTORY_PUBLIC_SHARE},
+	{"&TEMPLATES",    G_USER_DIRECTORY_TEMPLATES},
+	{"&VIDEOS",       G_USER_DIRECTORY_VIDEOS}
+};
+
+
+static gchar *
+get_user_special_dir_if_not_home (const gchar *path)
+{
+	int i;
+	const gchar *real_path;
+	GFile *home, *file;
+	gboolean res;
+
+	real_path = NULL;
+
+	for (i = 0; i < G_N_ELEMENTS(special_dirs); i++) {
+		if (strcmp (path, special_dirs[i].symbol) == 0) {
+			real_path = g_get_user_special_dir (special_dirs[i].user_dir);
+
+			if (real_path == NULL) {
+				g_warning ("Unable to get XDG user directory path for special "
+				           "directory %s. Ignoring this location.", path);
+			}
+
+			break;
+		}
+	}
+
+	if (real_path == NULL)
+		return NULL;
+
+	file = g_file_new_for_path (real_path);
+	home = g_file_new_for_path (g_get_home_dir ());
+
+	res = g_file_equal (file, home);
+	g_object_unref (file);
+	g_object_unref (home);
+
+	if (res) {
+		/* ignore XDG directories set to $HOME */
+		return NULL;
+	} else {
+		return g_strdup (real_path);
+	}
+}
+
+
 gchar *
 tracker_path_evaluate_name (const gchar *path)
 {
+	gchar        *special_dir_path;
 	gchar        *final_path;
 	gchar       **tokens;
 	gchar       **token;
@@ -495,6 +553,13 @@ tracker_path_evaluate_name (const gchar *path)
 		return NULL;
 	}
 
+	/* See if it is a special directory name. */
+	special_dir_path = get_user_special_dir_if_not_home (path);
+
+	if (special_dir_path != NULL) {
+		return special_dir_path;
+	}
+
 	/* First check the simple case of using tilder */
 	if (path[0] == '~') {
 		const gchar *home;
diff --git a/src/miners/fs/tracker-config.c b/src/miners/fs/tracker-config.c
index 7d5f4b523..415b9004b 100644
--- a/src/miners/fs/tracker-config.c
+++ b/src/miners/fs/tracker-config.c
@@ -524,29 +524,6 @@ config_finalize (GObject *object)
 	(G_OBJECT_CLASS (tracker_config_parent_class)->finalize) (object);
 }
 
-static gchar *
-get_user_special_dir_if_not_home (GUserDirectory directory)
-{
-	const gchar *path;
-	GFile *home, *file;
-	gboolean res;
-
-	path = g_get_user_special_dir (directory);
-	file = g_file_new_for_path (path);
-	home = g_file_new_for_path (g_get_home_dir ());
-
-	res = g_file_equal (file, home);
-	g_object_unref (file);
-	g_object_unref (home);
-
-	if (res) {
-		/* ignore XDG directories set to $HOME */
-		return NULL;
-	} else {
-		return g_strdup (path);
-	}
-}
-
 static GSList *
 dir_mapping_get (GSList   *dirs,
                  gboolean  is_recursive)
@@ -563,26 +540,7 @@ dir_mapping_get (GSList   *dirs,
 	for (l = filtered; l; l = l->next) {
 		gchar *path_to_use;
 
-		/* Must be a special dir */
-		if (strcmp (l->data, "&DESKTOP") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_DESKTOP);
-		} else if (strcmp (l->data, "&DOCUMENTS") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_DOCUMENTS);
-		} else if (strcmp (l->data, "&DOWNLOAD") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_DOWNLOAD);
-		} else if (strcmp (l->data, "&MUSIC") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_MUSIC);
-		} else if (strcmp (l->data, "&PICTURES") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_PICTURES);
-		} else if (strcmp (l->data, "&PUBLIC_SHARE") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_PUBLIC_SHARE);
-		} else if (strcmp (l->data, "&TEMPLATES") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_TEMPLATES);
-		} else if (strcmp (l->data, "&VIDEOS") == 0) {
-			path_to_use = get_user_special_dir_if_not_home (G_USER_DIRECTORY_VIDEOS);
-		} else {
-			path_to_use = tracker_path_evaluate_name (l->data);
-		}
+		path_to_use = tracker_path_evaluate_name (l->data);
 
 		if (path_to_use) {
 			evaluated_dirs = g_slist_prepend (evaluated_dirs, path_to_use);