Add Snell protocol. Refactor MASQUE HTTP/2, Fair Queue. Update XHTTP, OpenVPN, Sudoku, Fallback. Fixes

common/list/list.go

@@ -0,0 +1,164 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package list
+
+// Element is an element of a linked list.
+type Element[T any] struct {
+	next, prev *Element[T]
+	list       *List[T]
+	Value      T
+}
+
+func (e *Element[T]) Next() *Element[T] {
+	if p := e.next; e.list != nil && p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+func (e *Element[T]) Prev() *Element[T] {
+	if p := e.prev; e.list != nil && p != &e.list.root {
+		return p
+	}
+	return nil
+}
+
+func (e *Element[T]) Remove() bool {
+	if e.list == nil {
+		return false
+	}
+	e.list.remove(e)
+	return true
+}
+
+type List[T any] struct {
+	root Element[T]
+	len  int
+}
+
+func (l *List[T]) Init() *List[T] {
+	l.root.next = &l.root
+	l.root.prev = &l.root
+	l.len = 0
+	return l
+}
+
+func New[T any]() *List[T] { return new(List[T]).Init() }
+
+func (l *List[T]) Len() int { return l.len }
+
+func (l *List[T]) Front() *Element[T] {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.next
+}
+
+func (l *List[T]) Back() *Element[T] {
+	if l.len == 0 {
+		return nil
+	}
+	return l.root.prev
+}
+
+func (l *List[T]) lazyInit() {
+	if l.root.next == nil {
+		l.Init()
+	}
+}
+
+func (l *List[T]) insert(e, at *Element[T]) *Element[T] {
+	e.prev = at
+	e.next = at.next
+	e.prev.next = e
+	e.next.prev = e
+	e.list = l
+	l.len++
+	return e
+}
+
+func (l *List[T]) insertValue(v T, at *Element[T]) *Element[T] {
+	return l.insert(&Element[T]{Value: v}, at)
+}
+
+func (l *List[T]) remove(e *Element[T]) {
+	e.prev.next = e.next
+	e.next.prev = e.prev
+	e.next = nil
+	e.prev = nil
+	e.list = nil
+	l.len--
+}
+
+func (l *List[T]) Remove(e *Element[T]) T {
+	if e.list == l {
+		l.remove(e)
+	}
+	return e.Value
+}
+
+func (l *List[T]) PushFront(v T) *Element[T] {
+	l.lazyInit()
+	return l.insertValue(v, &l.root)
+}
+
+func (l *List[T]) PushBack(v T) *Element[T] {
+	l.lazyInit()
+	return l.insertValue(v, l.root.prev)
+}
+
+func (l *List[T]) InsertBefore(v T, mark *Element[T]) *Element[T] {
+	if mark.list != l {
+		return nil
+	}
+	return l.insertValue(v, mark.prev)
+}
+
+func (l *List[T]) InsertAfter(v T, mark *Element[T]) *Element[T] {
+	if mark.list != l {
+		return nil
+	}
+	return l.insertValue(v, mark)
+}
+
+func (l *List[T]) MoveToFront(e *Element[T]) {
+	if e.list != l || l.root.next == e {
+		return
+	}
+	l.move(e, &l.root)
+}
+
+func (l *List[T]) MoveToBack(e *Element[T]) {
+	if e.list != l || l.root.prev == e {
+		return
+	}
+	l.move(e, l.root.prev)
+}
+
+func (l *List[T]) MoveBefore(e, mark *Element[T]) {
+	if e.list != l || e == mark || mark.list != l {
+		return
+	}
+	l.move(e, mark.prev)
+}
+
+func (l *List[T]) MoveAfter(e, mark *Element[T]) {
+	if e.list != l || e == mark || mark.list != l {
+		return
+	}
+	l.move(e, mark)
+}
+
+func (l *List[T]) move(e, at *Element[T]) {
+	if e == at {
+		return
+	}
+	e.prev.next = e.next
+	e.next.prev = e.prev
+	e.prev = at
+	e.next = at.next
+	e.prev.next = e
+	e.next.prev = e
+}