lib: Add support for nested atomic sections.

[notmuch] / lib / notmuch.h

diff --git a/lib/notmuch.h b/lib/notmuch.h
index 974be8d1bec2fb52fb5e8ca8452b9f10a5521479..bfa2ced88a3f3893bc43b63ec495ce68fb41cd29 100644 (file)
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -81,6 +81,9 @@ typedef int notmuch_bool_t;
  * NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW: The notmuch_message_thaw
  *     function has been called more times than notmuch_message_freeze.
  *
+ * NOTMUCH_STATUS_UNBALANCED_ATOMIC: notmuch_database_end_atomic has
+ *     been called more times than notmuch_database_begin_atomic.
+ *
  * And finally:
  *
  * NOTMUCH_STATUS_LAST_STATUS: Not an actual status value. Just a way
@@ -97,6 +100,7 @@ typedef enum _notmuch_status {
     NOTMUCH_STATUS_NULL_POINTER,
     NOTMUCH_STATUS_TAG_TOO_LONG,
     NOTMUCH_STATUS_UNBALANCED_FREEZE_THAW,
+    NOTMUCH_STATUS_UNBALANCED_ATOMIC,
 
     NOTMUCH_STATUS_LAST_STATUS
 } notmuch_status_t;
@@ -214,6 +218,42 @@ notmuch_database_upgrade (notmuch_database_t *database,
                                                   double progress),
                          void *closure);
 
+/* Begin an atomic database operation.
+ *
+ * Any modifications performed between a successful begin and a
+ * notmuch_database_end_atomic will be applied to the database
+ * atomically.  Note that, unlike a typical database transaction, this
+ * only ensures atomicity, not durability; neither begin nor end
+ * necessarily flush modifications to disk.
+ *
+ * Atomic sections may be nested.  begin_atomic and end_atomic must
+ * always be called in pairs.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Successfully entered atomic section.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred;
+ *     atomic section not entered.
+ */
+notmuch_status_t
+notmuch_database_begin_atomic (notmuch_database_t *notmuch);
+
+/* Indicate the end of an atomic database operation.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Successfully completed atomic section.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred;
+ *     atomic section not ended.
+ *
+ * NOTMUCH_STATUS_UNBALANCED_ATOMIC: The database is not currently in
+ *     an atomic section.
+ */
+notmuch_status_t
+notmuch_database_end_atomic (notmuch_database_t *notmuch);
+
 /* Retrieve a directory object from the database for 'path'.
  *
  * Here, 'path' should be a path relative to the path of 'database'