ncdu/scan: remove option for memory representation

Remove files/directories from the in memory structs of the cloud
directory. Size and Count will be recalculated and populated upwards
to the parent directories.

cmd/ncdu/scan/scan.go

@@ -70,6 +70,45 @@ func (d *Dir) Entries() fs.DirEntries {
 	return append(fs.DirEntries(nil), d.entries...)
 }
 
+// Remove removes the i-th entry from the
+// in-memory representation of the remote directory
+func (d *Dir) Remove(i int) {
+	d.mu.Lock()
+	defer d.mu.Unlock()
+	d.remove(i)
+}
+
+// removes the i-th entry from the
+// in-memory representation of the remote directory
+//
+// Call with d.mu held
+func (d *Dir) remove(i int) {
+	size := d.entries[i].Size()
+	count := int64(1)
+
+	subDir, ok := d.getDir(i)
+	if ok {
+		size = subDir.size
+		count = subDir.count
+		delete(d.dirs, path.Base(subDir.path))
+	}
+
+	d.size -= size
+	d.count -= count
+	d.entries = append(d.entries[:i], d.entries[i+1:]...)
+
+	dir := d
+	// populate changed size and count to parent(s)
+	for parent := d.parent; parent != nil; parent = parent.parent {
+		parent.mu.Lock()
+		parent.dirs[path.Base(dir.path)] = dir
+		parent.size -= size
+		parent.count -= count
+		dir = parent
+		parent.mu.Unlock()
+	}
+}
+
 // gets the directory of the i-th entry
 //
 // returns nil if it is a file