[tracker/wip/carlosg/backports-for-3-1: 3/16] libtracker-common: Add GDateTime helper functions

[Carlos Garnacho <carlosg src gnome org>]

commit 4fc213c51cc04625595df6f0cb539665bc64333c
Author: Carlos Garnacho <carlosg gnome org>
Date:   Wed Apr 7 12:21:05 2021 +0200

    libtracker-common: Add GDateTime helper functions
    
    Add functions that allow parsing and producing ISO8601 exactly as
    we used to expect them.

 src/libtracker-common/tracker-date-time.c | 32 +++++++++++++++++++++++++++++++
 src/libtracker-common/tracker-date-time.h |  4 ++++
 2 files changed, 36 insertions(+)
---
diff --git a/src/libtracker-common/tracker-date-time.c b/src/libtracker-common/tracker-date-time.c
index 003239f6a..388a9725f 100644
--- a/src/libtracker-common/tracker-date-time.c
+++ b/src/libtracker-common/tracker-date-time.c
@@ -349,3 +349,35 @@ tracker_date_time_get_offset (const GValue *value)
        /* UTC offset */
        return value->data[1].v_int;
 }
+
+GDateTime *
+tracker_date_new_from_iso8601 (const gchar  *string,
+                              GError      **error)
+{
+       GDateTime *datetime;
+       GTimeZone *tz;
+
+       tz = g_time_zone_new_local ();
+       datetime = g_date_time_new_from_iso8601 (string, tz);
+       g_time_zone_unref (tz);
+
+       if (!datetime) {
+               g_set_error (error,
+                            TRACKER_DATE_ERROR,
+                            TRACKER_DATE_ERROR_INVALID_ISO8601,
+                            "'%s' is not a ISO 8601 date string. "
+                            "Allowed form is CCYY-MM-DDThh:mm:ss[.ssssss][Z|(+|-)hh:mm]",
+                            string);
+       }
+
+       return datetime;
+}
+
+gchar *
+tracker_date_format_iso8601 (GDateTime *datetime)
+{
+       if (g_date_time_get_utc_offset (datetime) == 0)
+               return g_date_time_format (datetime, "%C%y-%m-%dT%TZ");
+       else
+               return g_date_time_format (datetime, "%C%y-%m-%dT%T%:z");
+}
diff --git a/src/libtracker-common/tracker-date-time.h b/src/libtracker-common/tracker-date-time.h
index cd3111b49..6290b0d73 100644
--- a/src/libtracker-common/tracker-date-time.h
+++ b/src/libtracker-common/tracker-date-time.h
@@ -58,6 +58,10 @@ gdouble  tracker_string_to_date                (const gchar  *date_string,
 gchar *  tracker_date_to_string                (gdouble       date_time,
                                                 gint          offset);
 
+GDateTime * tracker_date_new_from_iso8601 (const gchar  *string,
+                                          GError      **error);
+gchar * tracker_date_format_iso8601 (GDateTime *datetime);
+
 G_END_DECLS
 
 #endif /* __LIBTRACKER_COMMON_DATE_TIME_H__ */