dirtree: add custom virtual directory role

Add a new directory role to indicate virtual nodes in the directory
tree. This allows to style the virtual nodes differently and apply
different behaviors in some commands (i.e. rmdir).

Signed-off-by: Koni Marti <[email protected]>
Acked-by: Robin Jarry <[email protected]>

app/dirtree.go

@@ -43,6 +43,30 @@ func (dt *DirectoryTree) OnVirtualNode(cb func()) {
 	dt.virtualCb = cb
 }
 
+func (dt *DirectoryTree) Selected() string {
+	if dt.listIdx < 0 || dt.listIdx >= len(dt.list) {
+		return dt.DirectoryList.Selected()
+	}
+	node := dt.list[dt.listIdx]
+	sep := dt.DirectoryList.worker.PathSeparator()
+	elems := strings.Split(dt.treeDirs[getAnyUid(node)], sep)
+	n := countLevels(node)
+	if n < 0 || n >= len(elems) {
+		return ""
+	}
+	return strings.Join(elems[:(n+1)], sep)
+}
+
+func (dt *DirectoryTree) SelectedDirectory() *models.Directory {
+	if dt.virtual {
+		return &models.Directory{
+			Name: dt.Selected(),
+			Role: models.VirtualRole,
+		}
+	}
+	return dt.DirectoryList.SelectedDirectory()
+}
+
 func (dt *DirectoryTree) ClearList() {
 	dt.list = make([]*types.Thread, 0)
 }

commands/account/rmdir.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"git.sr.ht/~rjarry/aerc/app"
+	"git.sr.ht/~rjarry/aerc/models"
 	"git.sr.ht/~rjarry/aerc/worker/types"
 )
 
@@ -31,6 +32,12 @@ func (r RemoveDir) Execute(args []string) error {
 		return errors.New("Refusing to remove non-empty directory; use -f")
 	}
 
+	if d := acct.Directories().SelectedDirectory(); d != nil {
+		if d.Role == models.VirtualRole {
+			return errors.New("Cannot remove a virtual node")
+		}
+	}
+
 	curDir := acct.SelectedDirectory()
 	var newDir string
 	dirFound := false

doc/aerc-templates.7.scd

@@ -194,8 +194,16 @@ available always.
 	{{.RUE}}
 	```
 
-	IANA role of the mailbox, converted to lowercase. aerc uses one custom
-	role: 'query', which is given to mailboxes from a notmuch query-map
+	IANA role of the mailbox, converted to lowercase:
+
+	```
+	{{.Role}}
+	```
+
+	*aerc* implements two additional custom roles: A 'query' role is given
+	to folders from a notmuch query-map
+	and 'virtual' indicates a virtual node in the directory tree listing:
+
 	```
 	{{if eq .Role "query"}}{{...}}{{else}}{{...}}{{end}}
 	```

models/models.go

@@ -59,6 +59,8 @@ const (
 	TrashRole   Role = "trash"
 	// Custom aerc roles
 	QueryRole Role = "query"
+	// virtual node created by the directory tree
+	VirtualRole Role = "virtual"
 )
 
 type Directory struct {