vendor: github.com/moby/buildkit db304eb93126 (v0.13.0-dev)

full diff: d6e142600e...db304eb931

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

vendor/google.golang.org/grpc/internal/backoff/backoff.go

@@ -23,6 +23,8 @@
 package backoff
 
 import (
+	"context"
+	"errors"
 	"time"
 
 	grpcbackoff "google.golang.org/grpc/backoff"
@@ -71,3 +73,37 @@ func (bc Exponential) Backoff(retries int) time.Duration {
 	}
 	return time.Duration(backoff)
 }
+
+// ErrResetBackoff is the error to be returned by the function executed by RunF,
+// to instruct the latter to reset its backoff state.
+var ErrResetBackoff = errors.New("reset backoff state")
+
+// RunF provides a convenient way to run a function f repeatedly until the
+// context expires or f returns a non-nil error that is not ErrResetBackoff.
+// When f returns ErrResetBackoff, RunF continues to run f, but resets its
+// backoff state before doing so. backoff accepts an integer representing the
+// number of retries, and returns the amount of time to backoff.
+func RunF(ctx context.Context, f func() error, backoff func(int) time.Duration) {
+	attempt := 0
+	timer := time.NewTimer(0)
+	for ctx.Err() == nil {
+		select {
+		case <-timer.C:
+		case <-ctx.Done():
+			timer.Stop()
+			return
+		}
+
+		err := f()
+		if errors.Is(err, ErrResetBackoff) {
+			timer.Reset(0)
+			attempt = 0
+			continue
+		}
+		if err != nil {
+			return
+		}
+		timer.Reset(backoff(attempt))
+		attempt++
+	}
+}