X-Git-Url: http://rtime.felk.cvut.cz/gitweb/notmuch.git/blobdiff_plain/91aede05a3964cc3748bf9940661c20bfd82771a..658a00e7c809cc4e3076aab28e105d3761086451:/lib/notmuch.h

diff --git a/lib/notmuch.h b/lib/notmuch.h
index 350bed8b..21a52252 100644
--- a/lib/notmuch.h
+++ b/lib/notmuch.h
@@ -159,6 +159,10 @@ typedef enum _notmuch_status {
      * The operation is not supported.
      */
     NOTMUCH_STATUS_UNSUPPORTED_OPERATION,
+    /**
+     * The operation requires a database upgrade.
+     */
+    NOTMUCH_STATUS_UPGRADE_REQUIRED,
     /**
      * Not an actual status value. Just a way to find out how many
      * valid status values there are.
@@ -287,8 +291,16 @@ notmuch_database_open (const char *path,
  *
  * notmuch_database_close can be called multiple times.  Later calls
  * have no effect.
+ *
+ * Return value:
+ *
+ * NOTMUCH_STATUS_SUCCESS: Successfully closed the database.
+ *
+ * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred; the
+ *	database has been closed but there are no guarantees the
+ *	changes to the database, if any, have been flushed to disk.
  */
-void
+notmuch_status_t
 notmuch_database_close (notmuch_database_t *database);
 
 /**
@@ -317,8 +329,11 @@ notmuch_database_compact (const char* path,
 /**
  * Destroy the notmuch database, closing it if necessary and freeing
  * all associated resources.
+ *
+ * Return value as in notmuch_database_close if the database was open;
+ * notmuch_database_destroy itself has no failure modes.
  */
-void
+notmuch_status_t
 notmuch_database_destroy (notmuch_database_t *database);
 
 /**
@@ -337,22 +352,27 @@ unsigned int
 notmuch_database_get_version (notmuch_database_t *database);
 
 /**
- * Does this database need to be upgraded before writing to it?
+ * Can the database be upgraded to a newer database version?
  *
- * If this function returns TRUE then no functions that modify the
- * database (notmuch_database_add_message, notmuch_message_add_tag,
- * notmuch_directory_set_mtime, etc.) will work unless the function
- * notmuch_database_upgrade is called successfully first.
+ * If this function returns TRUE, then the caller may call
+ * notmuch_database_upgrade to upgrade the database.  If the caller
+ * does not upgrade an out-of-date database, then some functions may
+ * fail with NOTMUCH_STATUS_UPGRADE_REQUIRED.  This always returns
+ * FALSE for a read-only database because there's no way to upgrade a
+ * read-only database.
  */
 notmuch_bool_t
 notmuch_database_needs_upgrade (notmuch_database_t *database);
 
 /**
- * Upgrade the current database.
+ * Upgrade the current database to the latest supported version.
  *
- * After opening a database in read-write mode, the client should
- * check if an upgrade is needed (notmuch_database_needs_upgrade) and
- * if so, upgrade with this function before making any modifications.
+ * This ensures that all current notmuch functionality will be
+ * available on the database.  After opening a database in read-write
+ * mode, it is recommended that clients check if an upgrade is needed
+ * (notmuch_database_needs_upgrade) and if so, upgrade with this
+ * function before making any modifications.  If
+ * notmuch_database_needs_upgrade returns FALSE, this will be a no-op.
  *
  * The optional progress_notify callback can be used by the caller to
  * provide progress indication to the user. If non-NULL it will be
@@ -427,6 +447,9 @@ notmuch_database_end_atomic (notmuch_database_t *notmuch);
  *
  * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred;
  *	directory not retrieved.
+ *
+ * NOTMUCH_STATUS_UPGRADE_REQUIRED: The caller must upgrade the
+ * 	database to use this function.
  */
 notmuch_status_t
 notmuch_database_get_directory (notmuch_database_t *database,
@@ -479,6 +502,9 @@ notmuch_database_get_directory (notmuch_database_t *database,
  *
  * NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
  *	mode so no message can be added.
+ *
+ * NOTMUCH_STATUS_UPGRADE_REQUIRED: The caller must upgrade the
+ * 	database to use this function.
  */
 notmuch_status_t
 notmuch_database_add_message (notmuch_database_t *database,
@@ -509,6 +535,9 @@ notmuch_database_add_message (notmuch_database_t *database,
  *
  * NOTMUCH_STATUS_READ_ONLY_DATABASE: Database was opened in read-only
  *	mode so no message can be removed.
+ *
+ * NOTMUCH_STATUS_UPGRADE_REQUIRED: The caller must upgrade the
+ * 	database to use this function.
  */
 notmuch_status_t
 notmuch_database_remove_message (notmuch_database_t *database,
@@ -564,6 +593,9 @@ notmuch_database_find_message (notmuch_database_t *database,
  * NOTMUCH_STATUS_OUT_OF_MEMORY: Out of memory, creating the message object
  *
  * NOTMUCH_STATUS_XAPIAN_EXCEPTION: A Xapian exception occurred
+ *
+ * NOTMUCH_STATUS_UPGRADE_REQUIRED: The caller must upgrade the
+ * 	database to use this function.
  */
 notmuch_status_t
 notmuch_database_find_message_by_filename (notmuch_database_t *notmuch,