notmuch: internally sort threads newest first

For proper thread ordering, notmuch needs to use a SORT_NEWEST_FIRST
sort order in it's query, and then we reverse the thread order. Also
give a maximum guess for size of slice we'll be returning.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 11 insertions, 1 deletions

diff --git a/worker/notmuch/lib/database.go b/worker/notmuch/lib/database.go
index 3b9de011..9a6689c4 100644
--- a/worker/notmuch/lib/database.go
+++ b/worker/notmuch/lib/database.go
@@ -117,12 +117,18 @@ func (db *DB) ThreadsFromQuery(ctx context.Context, q string) ([]*types.Thread,
 		return nil, err
 	}
 	defer query.Close()
+	// To get proper ordering of threads, we always sort newest first
+	query.Sort(notmuch.SORT_NEWEST_FIRST)
 	threads, err := query.Threads()
 	if err != nil {
 		return nil, err
 	}
+	n, err := query.CountMessages()
+	if err != nil {
+		return nil, err
+	}
 	defer threads.Close()
-	var res []*types.Thread
+	res := make([]*types.Thread, 0, n)
 	for threads.Next() {
 		select {
 		case <-ctx.Done():
@@ -136,6 +142,10 @@ func (db *DB) ThreadsFromQuery(ctx context.Context, q string) ([]*types.Thread,
 			thread.Close()
 		}
 	}
+	// Reverse the slice
+	for i, j := 0, len(res)-1; i < j; i, j = i+1, j-1 {
+		res[i], res[j] = res[j], res[i]
+	}
 	return res, err
 }