Initial QSfera import

Server/vendor/github.com/nats-io/nats.go/nats_iter.go

@@ -0,0 +1,72 @@
+// Copyright 2012-2024 The NATS 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 go1.23
+
+package nats
+
+import (
+	"errors"
+	"iter"
+	"time"
+)
+
+// Msgs returns an iter.Seq2[*Msg, error] that can be used to iterate over
+// messages. It can only be used with a subscription that has been created with
+// SubscribeSync or QueueSubscribeSync, otherwise it will return an error on the
+// first iteration.
+//
+// The iterator will block until a message is available. The
+// subscription will not be closed when the iterator is done.
+func (sub *Subscription) Msgs() iter.Seq2[*Msg, error] {
+	return func(yield func(*Msg, error) bool) {
+		for {
+			msg, err := sub.nextMsgNoTimeout()
+			if err != nil {
+				yield(nil, err)
+				return
+			}
+			if !yield(msg, nil) {
+				return
+			}
+
+		}
+	}
+}
+
+// MsgsTimeout returns an iter.Seq2[*Msg, error] that can be used to iterate
+// over messages. It can only be used with a subscription that has been created
+// with SubscribeSync or QueueSubscribeSync, otherwise it will return an error
+// on the first iteration.
+//
+// The iterator will block until a message is available or the timeout is
+// reached. If the timeout is reached, the iterator will return nats.ErrTimeout
+// but it will not be closed.
+func (sub *Subscription) MsgsTimeout(timeout time.Duration) iter.Seq2[*Msg, error] {
+	return func(yield func(*Msg, error) bool) {
+		for {
+			msg, err := sub.NextMsg(timeout)
+			if err != nil {
+				if !yield(nil, err) {
+					return
+				}
+				if !errors.Is(err, ErrTimeout) {
+					return
+				}
+			}
+			if !yield(msg, nil) {
+				return
+			}
+		}
+	}
+}