+/* Xapian (with flint backend) complains if we provide a term longer
+ * than this, but I haven't yet found a way to query the limit
+ * programmatically. */
+#define NOTMUCH_TERM_MAX 245
+
+typedef enum _notmuch_private_status {
+ /* First, copy all the public status values. */
+ NOTMUCH_PRIVATE_STATUS_SUCCESS = NOTMUCH_STATUS_SUCCESS,
+ NOTMUCH_PRIVATE_STATUS_OUT_OF_MEMORY = NOTMUCH_STATUS_OUT_OF_MEMORY,
+ NOTMUCH_PRIVATE_STATUS_XAPIAN_EXCEPTION = NOTMUCH_STATUS_XAPIAN_EXCEPTION,
+ NOTMUCH_PRIVATE_STATUS_FILE_NOT_EMAIL = NOTMUCH_STATUS_FILE_NOT_EMAIL,
+ NOTMUCH_PRIVATE_STATUS_NULL_POINTER = NOTMUCH_STATUS_NULL_POINTER,
+ NOTMUCH_PRIVATE_STATUS_TAG_TOO_LONG = NOTMUCH_STATUS_TAG_TOO_LONG,
+
+ /* Then add our own private values. */
+ NOTMUCH_PRIVATE_STATUS_TERM_TOO_LONG,
+ NOTMUCH_PRIVATE_STATUS_NO_DOCUMENT_FOUND,
+
+ NOTMUCH_PRIVATE_STATUS_LAST_STATUS
+} notmuch_private_status_t;
+
+/* Coerce a notmuch_private_status_t value to a notmuch_status_t
+ * value, generating an internal error if the private value is equal
+ * to or greater than NOTMUCH_STATUS_LAST_STATUS. (The idea here is
+ * that the caller has previously handled any expected
+ * notmuch_private_status_t values.)
+ */
+#define COERCE_STATUS(private_status, format, ...) \
+ ((private_status >= (notmuch_private_status_t) NOTMUCH_STATUS_LAST_STATUS)\
+ ? \
+ (notmuch_status_t) _internal_error (format " (%s).\n", \
+ ##__VA_ARGS__, \
+ __location__) \
+ : \
+ (notmuch_status_t) private_status)
+
+/* database.cc */
+
+/* Lookup a prefix value by name.
+ *
+ * XXX: This should really be static inside of message.cc, and we can
+ * do that once we convert database.cc to use the
+ * _notmuch_message_add/remove_term functions. */
+const char *
+_find_prefix (const char *name);
+
+/* thread.cc */
+
+notmuch_thread_t *
+_notmuch_thread_create (const void *talloc_owner,
+ notmuch_database_t *notmuch,
+ const char *thread_id);
+
+void
+_notmuch_thread_add_tag (notmuch_thread_t *thread, const char *tag);
+
+void
+_notmuch_thread_set_subject (notmuch_thread_t *thread, const char *subject);