+void
+_notmuch_message_set_date (notmuch_message_t *message,
+ const char *date)
+{
+ time_t time_value;
+
+ time_value = notmuch_parse_date (date, NULL);
+
+ message->doc.add_value (NOTMUCH_VALUE_TIMESTAMP,
+ Xapian::sortable_serialise (time_value));
+}
+
+static void
+thread_id_generate (thread_id_t *thread_id)
+{
+ static int seeded = 0;
+ FILE *dev_random;
+ uint32_t value;
+ char *s;
+ int i;
+
+ if (! seeded) {
+ dev_random = fopen ("/dev/random", "r");
+ if (dev_random == NULL) {
+ srand (time (NULL));
+ } else {
+ fread ((void *) &value, sizeof (value), 1, dev_random);
+ srand (value);
+ fclose (dev_random);
+ }
+ seeded = 1;
+ }
+
+ s = thread_id->str;
+ for (i = 0; i < NOTMUCH_THREAD_ID_DIGITS; i += 8) {
+ value = rand ();
+ sprintf (s, "%08x", value);
+ s += 8;
+ }
+}
+
+void
+_notmuch_message_ensure_thread_id (notmuch_message_t *message)
+{
+ /* If not part of any existing thread, generate a new thread_id. */
+ thread_id_t thread_id;
+
+ thread_id_generate (&thread_id);
+ _notmuch_message_add_term (message, "thread", thread_id.str);
+}
+
+/* Synchronize changes made to message->doc out into the database. */
+void
+_notmuch_message_sync (notmuch_message_t *message)
+{
+ Xapian::WritableDatabase *db = message->notmuch->xapian_db;
+
+ db->replace_document (message->doc_id, message->doc);
+}
+
+/* Add a name:value term to 'message', (the actual term will be
+ * encoded by prefixing the value with a short prefix). See
+ * NORMAL_PREFIX and BOOLEAN_PREFIX arrays for the mapping of term
+ * names to prefix values.
+ *
+ * This change will not be reflected in the database until the next
+ * call to _notmuch_message_set_sync. */
+notmuch_private_status_t
+_notmuch_message_add_term (notmuch_message_t *message,
+ const char *prefix_name,
+ const char *value)
+{
+
+ char *term;
+
+ if (value == NULL)
+ return NOTMUCH_PRIVATE_STATUS_NULL_POINTER;
+
+ term = talloc_asprintf (message, "%s%s",
+ _find_prefix (prefix_name), value);
+
+ if (strlen (term) > NOTMUCH_TERM_MAX)
+ return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
+
+ message->doc.add_term (term);
+
+ talloc_free (term);
+
+ return NOTMUCH_PRIVATE_STATUS_SUCCESS;
+}
+
+/* Remove a name:value term from 'message', (the actual term will be
+ * encoded by prefixing the value with a short prefix). See
+ * NORMAL_PREFIX and BOOLEAN_PREFIX arrays for the mapping of term
+ * names to prefix values.
+ *
+ * This change will not be reflected in the database until the next
+ * call to _notmuch_message_set_sync. */
+notmuch_private_status_t
+_notmuch_message_remove_term (notmuch_message_t *message,
+ const char *prefix_name,
+ const char *value)
+{
+ char *term;
+
+ if (value == NULL)
+ return NOTMUCH_PRIVATE_STATUS_NULL_POINTER;
+
+ term = talloc_asprintf (message, "%s%s",
+ _find_prefix (prefix_name), value);
+
+ if (strlen (term) > NOTMUCH_TERM_MAX)
+ return NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG;
+
+ message->doc.remove_term (term);
+
+ talloc_free (term);
+
+ return NOTMUCH_PRIVATE_STATUS_SUCCESS;
+}
+
+notmuch_status_t
+notmuch_message_add_tag (notmuch_message_t *message, const char *tag)
+{
+ notmuch_private_status_t status;
+
+ if (tag == NULL)
+ return NOTMUCH_STATUS_NULL_POINTER;
+
+ if (strlen (tag) > NOTMUCH_TAG_MAX)
+ return NOTMUCH_STATUS_TAG_TOO_LONG;
+
+ status = _notmuch_message_add_term (message, "tag", tag);
+ if (status) {
+ INTERNAL_ERROR ("_notmuch_message_add_term return unexpected value: %d\n",
+ status);
+ }
+
+ _notmuch_message_sync (message);
+
+ return NOTMUCH_STATUS_SUCCESS;
+}