Initial QSfera import

Server/vendor/github.com/minio/minio-go/v7/retry-continous.go

@@ -0,0 +1,65 @@
+/*
+ * MinIO Go Library for Amazon S3 Compatible Cloud Storage
+ * Copyright 2015-2017 MinIO, Inc.
+ *
+ * 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 minio
+
+import (
+	"iter"
+	"math"
+	"time"
+)
+
+// newRetryTimerContinous creates a timer with exponentially increasing delays forever.
+func (c *Client) newRetryTimerContinous(baseSleep, maxSleep time.Duration, jitter float64) iter.Seq[int] {
+	// normalize jitter to the range [0, 1.0]
+	if jitter < NoJitter {
+		jitter = NoJitter
+	}
+	if jitter > MaxJitter {
+		jitter = MaxJitter
+	}
+
+	// computes the exponential backoff duration according to
+	// https://www.awsarchitectureblog.com/2015/03/backoff.html
+	exponentialBackoffWait := func(attempt int) time.Duration {
+		// 1<<uint(attempt) below could overflow, so limit the value of attempt
+		maxAttempt := 30
+		if attempt > maxAttempt {
+			attempt = maxAttempt
+		}
+		// sleep = random_between(0, min(maxSleep, base * 2 ** attempt))
+		sleep := baseSleep * time.Duration(1<<uint(attempt))
+		if sleep > maxSleep {
+			sleep = maxSleep
+		}
+		if math.Abs(jitter-NoJitter) > 1e-9 {
+			sleep -= time.Duration(c.random.Float64() * float64(sleep) * jitter)
+		}
+		return sleep
+	}
+
+	return func(yield func(int) bool) {
+		var nextBackoff int
+		for {
+			if !yield(nextBackoff) {
+				return
+			}
+			nextBackoff++
+			time.Sleep(exponentialBackoffWait(nextBackoff))
+		}
+	}
+}