snapshot: sagernet/gvisor v0.0.0-20250811.0-sing-box-mod.1

Содержимое пина, зафиксированного в go.mod sing-box-lx, одним коммитом
без истории. Полная история SagerNet/gvisor — 1.45 ГБ и клонируется в
каждой CI-джобе; наша дельта — одна вставка в одну функцию, история для
неё не нужна.

Module path github.com/sagernet/gvisor сохранён намеренно: на него
опирается replace-директива суперпроекта.

Патч поверх — отдельным коммитом, чтобы дельта читалась одним git show
и переносилась на новый пин копированием.

SPECS/TASKS/048-GVISOR_HANDSHAKE_NIL_CRASH

pkg/ringdeque/ringdeque.go

@@ -0,0 +1,154 @@
+// Copyright 2024 The gVisor Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package ringdeque provides the Deque type.
+package ringdeque
+
+// A Deque implements a double-ended queue of values of type T using a
+// resizable ring buffer.
+//
+// Deque is not safe to use concurrently from multiple goroutines.
+type Deque[T any] struct {
+	// Items [off, off+len) modulo len(buf) in buf are valid.
+	// Invariants:
+	// - len(buf) is 0 or a power of 2.
+	// - If len(buf) == 0, off == 0; otherwise off < len(buf).
+	off uint64
+	len uint64
+	buf []T
+}
+
+// Preconditions: d.len == len(d.buf).
+func (d *Deque[T]) expand() {
+	newLen := 2 // arbitrary minimum
+	if d.len != 0 {
+		newLen = len(d.buf) * 2
+	}
+	newBuf := make([]T, newLen)
+	// By precondition, we need to copy every element in d.buf.
+	n := copy(newBuf, d.buf[d.off:])
+	copy(newBuf[n:], d.buf[:d.off])
+	d.off = 0
+	d.buf = newBuf
+}
+
+func (d *Deque[T]) mask() uint64 {
+	return uint64(len(d.buf)) - 1
+}
+
+// Empty returns true if r contains no values.
+func (d *Deque[T]) Empty() bool {
+	return d.len == 0
+}
+
+// Len returns the number of values in d.
+func (d *Deque[T]) Len() int {
+	return int(d.len)
+}
+
+// Clear removes all values from d.
+func (d *Deque[T]) Clear() {
+	d.len = 0
+}
+
+// PushFront inserts x at the front of d.
+func (d *Deque[T]) PushFront(x T) {
+	if int(d.len) == len(d.buf) {
+		d.expand()
+	}
+	newOff := (d.off - 1) & d.mask()
+	d.buf[newOff] = x
+	d.off = newOff
+	d.len++
+}
+
+// PushBack inserts x at the back of d.
+func (d *Deque[T]) PushBack(x T) {
+	if int(d.len) == len(d.buf) {
+		d.expand()
+	}
+	i := (d.off + d.len) & d.mask()
+	d.buf[i] = x
+	d.len++
+}
+
+// PeekFront returns the value at the front of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PeekFront() T {
+	return *d.PeekFrontPtr()
+}
+
+// PeekFrontPtr returns a pointer to the value at the front of d. The pointer
+// is only valid until the next mutation of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PeekFrontPtr() *T {
+	if d.Empty() {
+		panic("peek of empty Deque")
+	}
+	return &d.buf[d.off]
+}
+
+// PeekBack returns the value at the back of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PeekBack() T {
+	return *d.PeekBackPtr()
+}
+
+// PeekBackPtr returns a pointer to the value at the back of d. The pointer is
+// only valid until the next mutation of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PeekBackPtr() *T {
+	if d.Empty() {
+		panic("peek of empty Deque")
+	}
+	i := (d.off + d.len - 1) & d.mask()
+	return &d.buf[i]
+}
+
+// RemoveFront removes the value at the front of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) RemoveFront() {
+	d.off = (d.off + 1) & d.mask()
+	d.len--
+}
+
+// RemoveBack removes the value at the back of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) RemoveBack() {
+	d.len--
+}
+
+// PopFront removes and returns the value at the front of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PopFront() (x T) {
+	x = d.PeekFront()
+	d.RemoveFront()
+	return
+}
+
+// PopBack removes and returns the value at the back of d.
+//
+// Preconditions: !d.Empty().
+func (d *Deque[T]) PopBack() (x T) {
+	x = d.PeekBack()
+	d.RemoveBack()
+	return
+}