imap: use list-status for check-mail

Use list-status to perform check-mail commands, if it is available. This
provides a significant performance benefit by only requiring one IMAP
command vs one command for each mailbox.

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

3 files changed, 49 insertions, 26 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index f356122c..6931391c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Override the subject prefix prefix for replies pattern with
   `subject-re-pattern`.
 - Search/filter by absolute and relative date ranges with the `-d` flag.
+- LIST-STATUS support for imap
 
 ### Fixed
 
diff --git a/doc/aerc-imap.5.scd b/doc/aerc-imap.5.scd
index 787730df..c00f784f 100644
--- a/doc/aerc-imap.5.scd
+++ b/doc/aerc-imap.5.scd
@@ -10,6 +10,7 @@ aerc implements the IMAP protocol as specified by RFC 3501, with the following
 IMAP extensions:
 
 - IDLE (RFC 2177)
+- LIST-STATUS (RFC 5819)
 
 # CONFIGURATION
 
@@ -104,14 +105,16 @@ are available:
 *check-mail-include*
 	Specifies the comma separated list of folders to include when checking for
 	new mail with *:check-mail*. Names prefixed with _~_ are interpreted as regular
-	expressions.
+	expressions. This setting is ignored if your IMAP server supports the
+	LIST-STATUS command, in which case all folders will be checked.
 
 	By default, all folders are included.
 
 *check-mail-exclude*
 	Specifies the comma separated list of folders to exclude when checking for
 	new mail with *:check-mail*. Names prefixed with _~_ are interpreted as regular
-	expressions.
+	expressions. This setting is ignored if your IMAP server supports the
+	LIST-STATUS command, in which case all folders will be checked.
 	Note that this overrides anything from *check-mail-include*.
 
 	By default, no folders are excluded.
diff --git a/worker/imap/checkmail.go b/worker/imap/checkmail.go
index 34cf63d1..8f9e1b2b 100644
--- a/worker/imap/checkmail.go
+++ b/worker/imap/checkmail.go
@@ -13,36 +13,55 @@ func (w *IMAPWorker) handleCheckMailMessage(msg *types.CheckMail) {
 		imap.StatusRecent,
 		imap.StatusUnseen,
 	}
-	var remaining []string
-	for _, dir := range msg.Directories {
-		if len(w.worker.Actions) > 0 {
-			remaining = append(remaining, dir)
-			continue
-		}
-
-		log.Tracef("Getting status of directory %s", dir)
-		status, err := w.client.Status(dir, items)
+	var (
+		statuses  []*imap.MailboxStatus
+		err       error
+		remaining []string
+	)
+	switch {
+	case w.liststatus:
+		log.Tracef("Checking mail with LIST-STATUS")
+		statuses, err = w.client.liststatus.ListStatus("", "*", items, nil)
 		if err != nil {
 			w.worker.PostMessage(&types.Error{
 				Message: types.RespondTo(msg),
 				Error:   err,
 			}, nil)
-		} else {
-			w.worker.PostMessage(&types.DirectoryInfo{
-				Info: &models.DirectoryInfo{
-					Flags:          status.Flags,
-					Name:           status.Name,
-					ReadOnly:       status.ReadOnly,
-					AccurateCounts: true,
-
-					Exists: int(status.Messages),
-					Recent: int(status.Recent),
-					Unseen: int(status.Unseen),
-					Caps:   w.caps,
-				},
-				SkipSort: true,
-			}, nil)
+			return
 		}
+	default:
+		for _, dir := range msg.Directories {
+			if len(w.worker.Actions) > 0 {
+				remaining = append(remaining, dir)
+				continue
+			}
+			log.Tracef("Getting status of directory %s", dir)
+			status, err := w.client.Status(dir, items)
+			if err != nil {
+				w.worker.PostMessage(&types.Error{
+					Message: types.RespondTo(msg),
+					Error:   err,
+				}, nil)
+				continue
+			}
+			statuses = append(statuses, status)
+		}
+	}
+	for _, status := range statuses {
+		w.worker.PostMessage(&types.DirectoryInfo{
+			Info: &models.DirectoryInfo{
+				Flags:          status.Flags,
+				Name:           status.Name,
+				ReadOnly:       status.ReadOnly,
+				AccurateCounts: true,
+
+				Exists: int(status.Messages),
+				Recent: int(status.Recent),
+				Unseen: int(status.Unseen),
+				Caps:   w.caps,
+			},
+			SkipSort: true,
+		}, nil)
 	}
 	if len(remaining) > 0 {
 		w.worker.PostMessage(&types.CheckMailDirectories{