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/linewriter/linewriter.go

@@ -0,0 +1,79 @@
+// Copyright 2018 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 linewriter provides an io.Writer which calls an emitter on each line.
+package linewriter
+
+import (
+	"bytes"
+
+	"github.com/sagernet/gvisor/pkg/sync"
+)
+
+// Writer is an io.Writer which buffers input, flushing
+// individual lines through an emitter function.
+type Writer struct {
+	// the mutex locks buf.
+	sync.Mutex
+
+	// buf holds the data we haven't emitted yet.
+	buf bytes.Buffer
+
+	// emit is used to flush individual lines.
+	emit func(p []byte)
+}
+
+// NewWriter creates a Writer which emits using emitter.
+// The emitter must not retain p. It may change after emitter returns.
+func NewWriter(emitter func(p []byte)) *Writer {
+	return &Writer{emit: emitter}
+}
+
+// Write implements io.Writer.Write.
+// It calls emit on each line of input, not including the newline.
+// Write may be called concurrently.
+func (w *Writer) Write(p []byte) (int, error) {
+	w.Lock()
+	defer w.Unlock()
+
+	total := 0
+	for len(p) > 0 {
+		emit := true
+		i := bytes.IndexByte(p, '\n')
+		if i < 0 {
+			// No newline, we will buffer everything.
+			i = len(p)
+			emit = false
+		}
+
+		n, err := w.buf.Write(p[:i])
+		if err != nil {
+			return total, err
+		}
+		total += n
+
+		p = p[i:]
+
+		if emit {
+			// Skip the newline, but still count it.
+			p = p[1:]
+			total++
+
+			w.emit(w.buf.Bytes())
+			w.buf.Reset()
+		}
+	}
+
+	return total, nil
+}