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/gohacks/string_go113_unsafe.go

@@ -0,0 +1,51 @@
+// Copyright 2023 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.
+
+//go:build go1.13 && !go1.20
+// +build go1.13,!go1.20
+
+// TODO(go.dev/issue/8422): Remove this file once Go 1.19 is no longer
+// supported.
+
+package gohacks
+
+import (
+	"unsafe"
+)
+
+// stringHeader is equivalent to reflect.StringHeader, but represents the
+// pointer to the underlying array as unsafe.Pointer rather than uintptr,
+// allowing StringHeaders to be directly converted to strings.
+type stringHeader struct {
+	Data unsafe.Pointer
+	Len  int
+}
+
+// ImmutableBytesFromString is equivalent to []byte(s), except that it uses the
+// same memory backing s instead of making a heap-allocated copy. This is only
+// valid if the returned slice is never mutated.
+func ImmutableBytesFromString(s string) []byte {
+	shdr := (*stringHeader)(unsafe.Pointer(&s))
+	return Slice((*byte)(shdr.Data), shdr.Len)
+}
+
+// StringFromImmutableBytes is equivalent to string(bs), except that it uses
+// the same memory backing bs instead of making a heap-allocated copy. This is
+// only valid if bs is never mutated after StringFromImmutableBytes returns.
+func StringFromImmutableBytes(bs []byte) string {
+	// This is cheaper than messing with StringHeader and SliceHeader, which as
+	// of this writing produces many dead stores of zeroes. Compare
+	// strings.Builder.String().
+	return *(*string)(unsafe.Pointer(&bs))
+}