fix: restore reviewable migration evidence

proxy/timeout.go

@@ -0,0 +1,101 @@
+package proxy
+
+import (
+	"io"
+	"net/http"
+	"sync"
+	"sync/atomic"
+	"time"
+)
+
+type trackingBody struct {
+	io.ReadCloser
+	failed *atomic.Bool
+}
+
+func (b *trackingBody) Read(p []byte) (int, error) {
+	n, err := b.ReadCloser.Read(p)
+	if err != nil && err != io.EOF {
+		b.failed.Store(true)
+	}
+	return n, err
+}
+
+func responseBodyTimeout(resp *http.Response, opts Options) time.Duration {
+	if resp.StatusCode == http.StatusSwitchingProtocols {
+		return 0
+	}
+	if isStreamResponse(resp.Header) {
+		return opts.SSEIdleTimeout
+	}
+	return opts.ResponseTimeout
+}
+
+type timeoutBody struct {
+	body      io.ReadCloser
+	idle      bool
+	timeout   time.Duration
+	timer     *time.Timer
+	mu        sync.Mutex
+	done      bool
+	sequence  uint64
+	closeOnce sync.Once
+	closeErr  error
+}
+
+func newTimeoutBody(body io.ReadCloser, timeout time.Duration, idle bool) *timeoutBody {
+	t := &timeoutBody{body: body, idle: idle, timeout: timeout}
+	t.resetLocked()
+	return t
+}
+
+func (b *timeoutBody) Read(p []byte) (int, error) {
+	n, err := b.body.Read(p)
+	b.mu.Lock()
+	if !b.done {
+		if err != nil {
+			b.done = true
+			b.timer.Stop()
+		} else if n > 0 && b.idle {
+			b.resetLocked()
+		}
+	}
+	b.mu.Unlock()
+	return n, err
+}
+
+func (b *timeoutBody) Close() error {
+	b.mu.Lock()
+	if !b.done {
+		b.done = true
+		b.sequence++
+		b.timer.Stop()
+	}
+	b.mu.Unlock()
+	return b.closeUnderlying()
+}
+
+func (b *timeoutBody) resetLocked() {
+	if b.timer != nil {
+		b.timer.Stop()
+	}
+	b.sequence++
+	sequence := b.sequence
+	b.timer = time.AfterFunc(b.timeout, func() { b.expire(sequence) })
+}
+
+func (b *timeoutBody) expire(sequence uint64) {
+	b.mu.Lock()
+	if b.done || sequence != b.sequence {
+		b.mu.Unlock()
+		return
+	}
+	b.done = true
+	b.mu.Unlock()
+	_ = b.closeUnderlying()
+}
+
+func (b *timeoutBody) closeUnderlying() error {
+	b.closeOnce.Do(func() { b.closeErr = b.body.Close() })
+	return b.closeErr
+}