Change database to store only a single thread ID per message.

Instead of supporting multiple thread IDs, we now merge together
thread IDs if one message is ever found to belong to more than one
thread. This allows for constructing complete threads when, for
example, a child message doesn't include a complete list of References
headers back to the beginning of the thread.

It also simplifies dealing with mapping a message ID to a thread ID
which is now a simple get_thread_id just like get_message_id, (and no
longer an iterator-based thing like get_tags).

1 files changed, 15 insertions, 74 deletions

diff --git a/notmuch.h b/notmuch.h
index ef29fb57..a6f3f5d4 100644
--- a/notmuch.h
+++ b/notmuch.h
@@ -105,7 +105,6 @@ typedef struct _notmuch_query notmuch_query_t;
 typedef struct _notmuch_results notmuch_results_t;
 typedef struct _notmuch_message notmuch_message_t;
 typedef struct _notmuch_tags notmuch_tags_t;
-typedef struct _notmuch_thread_ids notmuch_thread_ids_t;
 
 /* Lookup the default database path.
  *
@@ -417,6 +416,21 @@ notmuch_results_destroy (notmuch_results_t *results);
 const char *
 notmuch_message_get_message_id (notmuch_message_t *message);
 
+
+/* Get the thread ID of 'message'.
+ *
+ * The returned string belongs to 'message' and as such, should not be
+ * modified by the caller and will only be valid for as long as the
+ * message is valid, (for example, until the user calls
+ * notmuch_message_destroy on 'message' or until a query from which it
+ * derived is destroyed).
+ *
+ * This function will not return NULL since Notmuch ensures that every
+ * message belongs to a single thread.
+ */
+const char *
+notmuch_message_get_thread_id (notmuch_message_t *message);
+
 /* Get the filename for the email corresponding to 'message'.
  *
  * The returned filename is relative to the base of the database from
@@ -460,39 +474,6 @@ notmuch_message_get_filename (notmuch_message_t *message);
 notmuch_tags_t *
 notmuch_message_get_tags (notmuch_message_t *message);
 
-/* Get the thread IDs for 'message', returning a notmuch_thread_ids_t
- * object which can be used to iterate over all thread IDs.
- *
- * The thread_ids object is owned by the message and as such, will
- * only be valid for as long as the message is valid, (which is until
- * the query from which it derived is destroyed).
- *
- * Typical usage might be:
- *
- *     notmuch_message_t *message;
- *     notmuch_thread_ids_t *thread_ids;
- *     const char *thread_id;
- *
- *     message = notmuch_database_find_message (database, message_id);
- *
- *     for (thread_ids = notmuch_message_get_thread_ids (message);
- *          notmuch_thread_ids_has_more (thread_ids);
- *          notmuch_thread_ids_advance (thread_ids))
- *     {
- *         thread_id = notmuch_thread_ids_get (thread_ids);
- *         ....
- *     }
- *
- *     notmuch_message_destroy (message);
- *
- * Note that there's no explicit destructor needed for the
- * notmuch_thread_ids_t object. (For consistency, we do provide a
- * notmuch_thread_ids_destroy function, but there's no good reason to
- * call it if the message is about to be destroyed).
- */
-notmuch_thread_ids_t *
-notmuch_message_get_thread_ids (notmuch_message_t *message);
-
 /* The longest possible tag value. */
 #define NOTMUCH_TAG_MAX 200
 
@@ -575,46 +556,6 @@ notmuch_tags_advance (notmuch_tags_t *tags);
 void
 notmuch_tags_destroy (notmuch_tags_t *tags);
 
-/* Does the given notmuch_thread_ids_t object contain any more thread IDs.
- *
- * When this function returns TRUE, notmuch_thread_ids_get will return a
- * valid string. Whereas when this function returns FALSE,
- * notmuch_thread_ids_get will return NULL.
- *
- * See the documentation of notmuch_message_get_thread_ids for example code
- * showing how to iterate over a notmuch_thread_ids_t object.
- */
-notmuch_bool_t
-notmuch_thread_ids_has_more (notmuch_thread_ids_t *thread_ids);
-
-/* Get the current thread ID from 'thread_ids' as a string.
- *
- * Note: The returned string belongs to 'thread_ids' and has a lifetime
- * identical to it (and the query to which it utlimately belongs).
- *
- * See the documentation of notmuch_message_get_thread_ids for example code
- * showing how to iterate over a notmuch_thread_ids_t object.
- */
-const char *
-notmuch_thread_ids_get (notmuch_thread_ids_t *thread_ids);
-
-/* Advance the 'thread_ids' iterator to the next tag.
- *
- * See the documentation of notmuch_message_get_thread_ids for example code
- * showing how to iterate over a notmuch_thread_ids_t object.
- */
-void
-notmuch_thread_ids_advance (notmuch_thread_ids_t *thread_ids);
-
-/* Destroy a notmuch_thread_ids_t object.
- *
- * It's not strictly necessary to call this function. All memory from
- * the notmuch_thread_ids_t object will be reclaimed when the containg
- * message or query objects are destroyed.
- */
-void
-notmuch_thread_ids_destroy (notmuch_thread_ids_t *thread_ids);
-
 NOTMUCH_END_DECLS
 
 #endif