dirstore: list the folders in arrival order

List the folders in arrival order when dirstore.List() is called instead
of returning it in an arbitrary order.

If enable-folders-sort=false and dirlist-tree=false, the directory list
will arbitrarly reshuffle when changing directories because the
dirlist.dirs are generated from keys in a map in the dirstore.

Fixes: https://todo.sr.ht/~rjarry/aerc/178
Signed-off-by: Koni Marti <koni.marti@gmail.com>
Acked-by: Robin Jarry <robin@jarry.cc>

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/sort/sort.go b/lib/sort/sort.go
index c7e2b8ce..287f986c 100644
--- a/lib/sort/sort.go
+++ b/lib/sort/sort.go
@@ -70,3 +70,15 @@ func SortBy(toSort []uint32, sortBy []uint32) {
 		return uidMap[toSort[i]] < uidMap[toSort[j]]
 	})
 }
+
+// SortStringBy sorts the string slice s according to the order given in the
+// order string slice.
+func SortStringBy(s []string, order []string) {
+	m := make(map[string]int)
+	for i, d := range order {
+		m[d] = i
+	}
+	sort.Slice(s, func(i, j int) bool {
+		return m[s[i]] < m[s[j]]
+	})
+}